BRPI0911514B1 - "Oxidation Catalyst and Process for Oxidation of a Substrate" - Google Patents

Description

(54) Title: OXIDATION CATALYST AND PROCESS FOR THE OXIDATION OF A SUBSTRATE (51) Int.CI .: B01J 23/56; C07F 9/38; B01J 35/00; B01J 35/10; B01J 23/62; B01J 23/89; B01J 21/18; B01J 37/02 (30) Unionist Priority: 05/01/2008 US 61 / 049,465 (73) Holder (s): MONSANTO TECHNOLOGY LLC (72) Inventor (s): KAM-TO WAN

Descriptive Report of the Invention Patent for OXIDATION CATALYST AND PROCESS FOR THE OXIDATION OF A SUBSTRATE.

Field of the Invention

The present invention relates, in general, to improvements in the use of metal in catalysts containing metals in the support. For example, the present invention relates to methods for directing and / or controlling the deposit of metal on surfaces of porous substrates. More particularly, some embodiments of the present invention relate to methods for treating porous substrates (for example, porous carbon substrates or porous metal substrates) to provide substrates treated with one or more desirable properties (for example, a reduced attributable surface area pores with a nominal diameter within a predefined range) that can be used as supports for catalysts containing metals.

The present invention also relates to methods for preparing catalysts in which a first metal is deposited on a support (for example, a porous carbon support) to provide one or more regions of a first metal on the surface of the support, and a second metal is deposited on the surface of one or more regions of the first metal. Generally, the electropositivity of the first metal (for example, copper or iron) is greater than the electropositivity of the second metal (for example, a noble metal such as platinum) and the second metal is deposited on the surface of one or more regions of the first metal by displacing the first metal.

The present invention also relates to treated substrates, catalyst precursor structures and catalysts prepared by the methods.

The invention further relates to the use of catalysts prepared as detailed here in catalytic oxidation reactions, such as the oxidation of a substrate selected from the group consisting of iminodiacetic N- (phosphonomethyl) acid or a salt thereof, formaldehyde and / or formic acid.

Background of the Invention

N- (phosphonomethyl) glycine (known in the agricultural chemical industry as glyphosate) is described, in United States Patent US 3,799,758, of

Petition 870180000369, of 01/03/2018, p. 5/14

Franz. Glyphosate and its salts are conveniently applied as a post-emergent herbicide in aqueous formulations. It is a commercially important and highly effective broad-spectrum herbicide, useful for killing or controlling the growth of a wide variety of plants, including germinating seeds, new seedlings, with mature herbaceous and woody vegetation, and aquatic plants.

Various methods for the production of glyphosate are known in the art, including several methods that use catalysts containing noble metals supported on carbon. See, for example, U.S. Patent No.

6,417,133 to Ebner et al. and International Publication in WO 2006/031938 by Wan et al. Generally, these methods include oxidative liquid-phase dividing of iminodiacetic acid N- (phosphonomethyl) (i.e. PMIDA) in the presence of a carbon-containing noble metal catalyst. Along with the glyphosate product, various by-products can form, such as formaldehyde, formic acid (which is formed by oxidation of the formaldehyde by-product), aminomethylphosphonic acid (AMPA) and methyl aminomethylphosphonic acid (MAMPA), which are formed by oxidation of N- (phosphonomethyl) glycine and iminodiacetic acid (IDA), which is formed by PMIDA These by-products can reduce glyphosate production (for example, AMPA and / or MAMPA) and can present toxicity problems (for example, formaldehyde). Thus, the significant formation of by-products is preferably avoided.

It is well known in the art, including, for example, as described in US 6,417,133 by Ebner et al. and in International Publication No. WO 2006/031938 by Wan et al., that carbon primarily catalyzes the oxidation of PMIDA to glyphosate and the noble metal primarily catalyzes the oxidation of by-product formaldehyde to carbon dioxide and water. The catalysts of Ebner et al. in US

6,417,133 and Wan et al. in WO 2006/031938 proved to be highly advantageous and effective catalysts for the oxidation of PMIDA to glyphosate and for the oxidation of by-products formaldehyde and formic acid to carbon dioxide and water, without excessive leaching of noble metals from the carbon support. These catalysts are equally effective in operating a continuous process for the production of glyphosate by oxidation of PMIDA.

Although these catalysts are efficient in oxidizing PMIDA and are generally resistant to leaching of noble metals, under PMIDA oxidation conditions, there are opportunities for improvement.

For example, the distribution and / or pore size of the porous substrates used in catalysts containing noble metals can affect the performance of the catalyst and the use of the metal. Methods for introducing compounds (i.e., compounds that block pores) into the pores of substrates to modify metal deposition are known in the art. See, for example, U.S. Patent No. 5,439,859 to Durante et al.

An object of the present invention is the development of effective catalysts for the oxidation of PMIDA, formaldehyde and / or formic acid, which more efficiently uses the expensive noble metal, and methods for its preparation. The more efficient use of metal can provide more active catalysts than conventional catalysts. Another object of the present invention is the development of methods for the preparation of effective catalysts that require a reduced ratio of the expensive noble metal compared to conventional catalysts, while still having adequate activity.

Summary of the Invention

This invention provides catalysts and methods for preparing catalysts that are useful in heterogeneous oxidation reactions, including the preparation of glyphosate by the oxidation of PMIDA.

In summary, therefore, the present invention is directed to oxidation catalysts that comprise a particulate carbon support, a first metal and a second metal, the support having on its surface particles that make up the first metal and the second metal.

In at least one embodiment, the distribution of the second metal within at least one of the particles, characterized by the in-line scanning analysis of X-ray dispersive energy (EDX), as described in Protocol B, produces a second metal signal that varies by no more than about 25% over a scanning region having a dimension that is at least about 70% of the largest dimension of at least one particle. In an additional embodiment, the distribution of the second metal within at least one of the particles as characterized by the EDX line scan analysis, as described in Protocol B produces a second metal signal that varies by no more than about 20% over a scanning region having a dimension that is at least about 60% of the largest dimension of at least one particle. In another embodiment, the distribution of the second metal within at least one of the particles as characterized by the EDX in-line scan analysis, as described in Protocol B produces a second metal signal that varies by no more than about 15% in a scanning region having a dimension that is at least about 50% of the largest dimension of the at least one particle.

The present invention is also directed to an oxidation catalyst comprising a support of particulate carbon, copper and platinum, the support having on its surface particles comprising copper and platinum. The distribution of platinum within at least 70% (base number) of particles as characterized by the EDX in-line scan analysis, as described in Protocol B produces a platinum signal that varies by no more than about 25% over a scanning region having a dimension that is at least about 70% of the largest dimension of said particles.

The present invention is also directed to an oxidation catalyst comprising a particulate carbon support, a first metal and a noble metal, the support having on its surface metal particles comprising the first metal and the noble metal. The catalyst is characterized as the chemisorption of at least 975 μmols of CO per gram of catalyst per gram of noble metal during Cycle 2 of the static carbon monoxide chemisorption analysis, as described in protocol A.

The present invention is also directed to an oxidation catalyst which comprises a particulate carbon support, a first metal and a noble metal, the support on its surface metal particles comprising the first metal and the noble metal, in which the particles of metal comprise a core comprising the first metal and a shell at least partially surrounding the core and comprising the noble metal, wherein at least about 70% of the noble metal is present within the particle shell.

In a further embodiment, the present invention is directed to an oxidation catalyst comprising a support of particulate carbon, platinum and copper, the support having on its surface metal particles comprising platinum and copper, in which the percentage of the platinum atom on the surface of the particles is at least about 10%.

In a still further embodiment, the present invention is directed to an oxidation catalyst comprising a particulate carbon support, a first metal and a noble metal, the support having on its surface metal particles comprising the first metal and the noble metal , in which the metal particles comprise a core comprising the first metal and a shell at least partially surrounding the core including the noble metal, and the catalyst is characterized as the chemisorption in at least 975 μmoles of CO per gram of noble metal catalyst per gram in cycle 2 of the static carbon monoxide chemisorption analysis, as described in protocol A.

In another embodiment, the present invention is directed to an oxidation catalyst comprising a support of particulate carbon, platinum and copper, the support having on its surface metal particles comprising platinum and copper, in which the percentage of the platinum atom in the particle surface is at least about 5%, and the catalyst is characterized as the chemisorption of at least 500 μmoles of CO per gram of catalyst per gram of the noble metal during Cycle 2 of the static carbon monoxide chemisorption analysis , as described in protocol A.

In a still further embodiment, the present invention is directed to an oxidation catalyst comprising a particulate carbon support, a first metal and a noble metal, the support having on its surface metal particles comprising the first metal and the noble metal , in which the metal particles comprise a core comprising the first metal and a shell at least partially surrounding the core including the noble metal, the noble metal constitutes less than 5% by weight of the catalyst, and the catalyst is characterized as chemisorption of at least about 800 μmoles of CO per gram of catalyst per gram of noble metal during Cycle 2 of the static carbon monoxide chemisorption analysis, as described in protocol A.

The present invention is also directed to an oxidation catalyst comprising a particulate carbon support with metal particles on a surface thereof comprising a first metal and a second metal, where the electropositivity of the first metal is greater than the electropositivity of the second metal and the second metal is deposited by displacing the first metal ions from one or more regions of the first metal in a catalyst precursor structure and the weight ratio of the second metal to the first metal is at least about 0.25: 1.

The present invention is also directed to processes for oxidizing a substrate selected from the group consisting of N- (phosphonomethyl) iminodiacetic acid or a salt thereof, formaldehyde and formic acid. Generally, the process comprises contacting the substrate with an oxidizing agent in the presence of an oxidation catalyst prepared by the methods detailed herein and / or as described herein. For example, in one embodiment, the catalyst comprises a first metal, a noble metal, and a porous carbon support, the catalyst comprising one or more regions of first metal on the surface of the carbon support and one or more regions of noble metal in the surface of one or more regions of the first metal, where the first metal has a greater electropositivity than the nobility of the noble metal.

The present invention is further directed to various methods of preparing a catalyst comprising a first metal, a second metal and a porous support with a surface comprising pores of a nominal diameter within a predefined range and pores of a nominal diameter outside the predefined range .

In one embodiment, the method comprises having a pore blocking agent within the pores of the porous support having a nominal diameter within the predefined range, the pore blocking agent having at least one dimension in relation to the opening of the pores with a nominal diameter inside the predefined range such that the pore blocking agent is preferably kept within the pores; contacting the support with a first metal deposition bath comprising an aqueous medium and ions of the first metal, thus depositing the first metal on the surface of the porous support within the pores having a nominal diameter outside the predefined range to form a precursor structure of catalyst having one or more regions of the first deposited metal and on the support surface between pores of a nominal diameter outside the predefined range, and contacting the catalyst precursor structure with a second metal deposition bath comprising ions of the second metal, thus depositing the second metal on the surface of the catalyst precursor structure.

In another embodiment, the method comprises contacting the support and the first metal deposition bath comprising an aqueous medium, the ions of the first metal, and a coordinating agent that forms a coordination compound with the first metal having at least one larger than the nominal pore diameter within the predefined range, thus depositing the first metal on the support surface within the pore having a nominal diameter outside the predefined range to form a catalyst precursor structure having one or more regions of the first metal deposited on the surface of the support, and contacting the catalyst precursor structure with a second metal deposition bath comprising ions of the second metal, thus depositing the second metal on the surface of the catalyst precursor structure.

The present invention is also directed to methods for preparing catalysts that comprise a first metal, a second metal and a porous carbon support.

In one embodiment, the method comprises contacting the porous carbon support with a first metal deposition bath comprising the ions of the first metal, thereby depositing the first metal on the surface of the porous carbon support to form a catalyst precursor structure, with one or more regions of the first metal deposited on the surface of the support, where the first metal has a greater electropositivity than the electropositivity of the second metal; contacting the catalyst precursor structure with a second metal deposition bath comprising ions of the second metal, thereby depositing the second metal on the surface of the catalyst precursor structure by displacing the first metal from one or more of the regions; and heating the catalyst precursor structure with the first and second metals deposited on the surface of the catalyst precursor structure to a temperature of at least about 500 ° C in a non-oxidizing environment.

In an additional embodiment, the method comprises contacting the porous carbon support with a first metal deposition bath comprising ions of the first metal, thus depositing the first metal on the surface of the porous carbon support to form a catalyst precursor structure having one or more regions of the first metal deposited on the surface of the support, where the carbon support has a Langmuir surface area of at least about 500 m ² / g, and the first metal has a greater electropositivity than the electropositivity of the second metal; and contacting the catalyst precursor structure with a second metal deposition bath comprising ions of the second metal, thereby depositing the second metal on the surface of the catalyst precursor structure by displacing the first metal from one or more regions.

The present invention is also directed to methods for preparing a catalyst comprising a first metal, a noble metal, and a porous support. In one embodiment, the method comprises contacting the support and a first metal deposition bath comprising an aqueous medium, ions of the first metal and a coordinating agent that forms a coordination compound with the first metal, thereby depositing the first metal on the surface of the support to form a catalyst precursor structure having one or more regions of the first metal deposited on the surface of the support, where the first metal has a greater electropositivity than the electropositivity of the noble metal; and contacting the catalyst precursor structure with a noble metal deposition bath comprising noble metal ions, thereby depositing the noble metal on the surface of the catalyst precursor structure by displacing the first metal from one or more regions.

In an additional embodiment, the method comprises contacting the support with a first metal deposition bath comprising an aqueous medium and ions of the first metal, and thus depositing the first metal on the surface of the support to form a catalyst precursor structure having a or more regions of the first metal deposited on the surface of the support, where the first metal has a greater electropositivity than the nobility of the noble metal; and contacting the catalyst precursor structure with a noble metal deposition bath comprising noble metal ions, thereby depositing the noble metal on the surface of the catalyst precursor structure by displacing the first metal from one or more of the regions, in that substantially all noble metals are deposited by displacement, or noble metal ions consist essentially of noble metal ions having an oxidation number of 2.

In another embodiment, the method comprises contacting the support with a first metal deposition bath which comprises an aqueous medium, ions of the first metal, and a pore blocking agent, thereby disposing the pore blocking agent within the pores of the substrate having a nominal diameter within a predefined range, wherein the pore blocking agent is at least one dimension in relation to the pore opening of the predefined range sufficient for the pore blocking agent to be preferably maintained within the pores, and to deposit the first metal on the support surface within the pores having a nominal diameter outside the predefined range, forming a catalyst precursor structure having one or more regions of the first metal deposited on the support surface, where the first metal has a greater electropositivity than the electropositivity of the noble metal, and contact the structure of the catalyst precursor with a dep bath noble metal placement comprising noble metal ions, thus depositing the noble metal on the surface of the catalyst precursor structure by displacing the first metal from one or more regions.

The present invention is also directed to methods for preparing a catalyst comprising a first metal, a noble metal, and a porous support having a surface comprising pores of a nominal diameter within a predefined range and pores of a nominal diameter outside the predefined range. . In one embodiment, the method comprises contacting the support and a first metal deposition bath comprising an aqueous medium, the ions of the first metal and a coordinating agent that forms a coordination compound with the first metal having at least a larger dimension than the nominal pore diameter within the predefined range, thus depositing the first metal on the support surface within the pore having a nominal diameter outside the predefined range to form a catalyst precursor structure having one or more regions of the first metal deposited on the surface of the support, and contacts the catalyst precursor structure with a noble metal deposition bath comprising noble metal ions, thereby depositing the noble metal on the surface of the catalyst precursor structure.

The present invention is also directed to methods for preparing catalysts that comprise platinum, copper, and a porous carbon support.

In one embodiment, the method comprises contacting the support with a copper deposition bath comprising copper ions and a coordinating agent, in the absence of an externally applied tension, thus depositing copper on the surface of the porous carbon support to form a catalyst precursor structure having one or more copper regions deposited on the support surface, and contacts the catalyst precursor structure and a platinum deposition bath comprising platinum ions, thereby depositing platinum on the surface of the catalyst precursor structure by displacing copper from one or more of the regions.

In another embodiment, the method comprises contacting the support and a copper deposition bath comprising copper ions in the absence of an externally applied tension, thus depositing copper on the surface of the carbon support to form a catalyst precursor structure with one or more copper regions deposited on the surface of the support, where the carbon support has a Langmuir surface of at least about 500 m ² / g before depositing copper on it, and contacting the catalyst precursor structure and a platinum deposition bath comprising platinum ions, thus depositing platinum on the surface of the catalyst precursor structure by displacing copper from one or more regions.

In an additional embodiment, the method comprises contacting the support and a copper deposition bath comprising copper ions in the absence of an externally applied voltage, thus depositing copper on the surface of the carbon support to form a catalyst precursor structure having one or more copper regions deposited on the surface of the support, contact the catalyst precursor structure and a platinum deposition bath comprising platinum ions, thus depositing platinum on the surface of the catalyst precursor structure by displacing copper from one or more regions, and heat the surface of the catalyst precursor having platinum with the surface of one or more copper regions to a temperature of at least about 500 ° C in a non-oxidizing environment.

The present invention is also directed to methods for preparing catalysts that comprise iron, platinum and a porous carbon support.

In one embodiment, the method comprises contacting the support with an iron deposition bath comprising iron ions and a coordinating agent, in the absence of an externally applied tension, thereby depositing iron on the surface of the porous carbon support to form a structure catalyst precursor having one or more iron deposition regions on the support surface, and contacting the catalyst precursor structure and a platinum deposition bath comprising platinum ions, thereby depositing platinum on the surface of the catalyst precursor structure by the displacement of iron from one or more of the regions.

In another embodiment, the method comprises contacting the support and an iron deposition bath comprising iron ions, in the absence of an externally applied tension, thus depositing iron on the surface of the carbon support to form a catalyst precursor structure with a or more regions of iron deposited on the surface of the support, where the carbon support has a Langmuir surface area of at least about 500 m ² / g before deposition of the iron in it, and contact the catalyst precursor structure and a platinum deposition bath comprising platinum ions, thus depositing platinum on the surface of the catalyst precursor structure by displacing iron from one or more regions.

In an additional embodiment, the method comprises contacting the support and an iron deposition bath comprising iron ions, in the absence of an externally applied tension, thus depositing iron on the surface of the carbon support to form a catalyst precursor structure having one or more regions of iron deposited on the surface of the support; contacting the catalyst precursor structure and a platinum deposition bath comprising of platinum ions, thereby depositing platinum on the surface of the catalyst precursor structure by displacing iron from one or more of the regions; and heating the surface of the catalyst precursor having platinum on the surface of one or more regions of iron in a non-oxidizing environment.

The present invention is also directed to methods for treating a porous substrate to prepare a modified porous substrate having a reduced surface area attributable to the pores having a nominal diameter within a predefined range.

In one embodiment, the method comprises arranging a pore blocking agent within the pores of the porous substrate having a nominal diameter within the predefined range, the pore blocking agent having at least one dimension relative to the opening of the pores with a nominal diameter in the within the predefined range sufficient that the pore blocking agent is preferably kept within the pores.

In another embodiment, the method comprises introducing a pore blocking compound into the pores of the porous substrate, the pore blocking compound being susceptible to a conformational change such that the pore blocking compound is maintained within the pores of the porous substrate having a diameter within the predefined range.

In an additional embodiment, the method comprises introducing pores with a nominal diameter within a predefined range of compounds capable of forming a pore blocking compound having at least one dimension such that the pore blocking compound is maintained within the pores having a nominal diameter within a predefined range.

The present invention is also directed to methods for the treatment of porous substrates with micropores and pores of larger diameter to prepare a modified porous substrate with a reduced surface area of micropores.

In one embodiment, the method comprises arranging a pore blocking agent within the pores of the porous substrate, the pore blocking agent having at least one dimension in relation to the opening of the micropores in such a way that the pore blocking agent is preferably kept in the pores.

In another embodiment, the method comprises introducing a pore blocking compound into the pores of the porous substrate, the pore blocking compound being susceptible to a conformational change such that the pore blocking compound is kept within the pores of the porous substrate.

In a further embodiment, the method comprises introducing substrate compounds into the micropores capable of forming a pore blocking compound having at least one dimension such that the pore blocking compound is maintained within the micropores.

Still in an additional embodiment, the method comprises introducing a pore blocking composition into the pores of the porous substrate, the pore blocking composition comprising a substituted cyclohexane derivative.

The present invention is also directed to methods for preparing a catalyst comprising a metal on the surface of a porous substrate in which the metal is preferably excluded from pores of the porous substrate with a nominal diameter within a predefined range. In one embodiment, the method comprises (i) introducing one or more precursors of a pore blocking compound into the pores of the porous substrate, where: where at least one of the precursors of the pore blocking compound is sensitive to a conformational change to form a pore blocking compound that is maintained within the pores of the porous substrate with a nominal diameter within the predefined range, or at least two precursors of pore blocking compounds are capable of forming a pore blocking compound having at least one dimension such that the compound is kept within the pores of the porous substrate with a nominal diameter within a predefined range; (ii) preferably removing the pore blocking compound from the pores of the porous substrate with a nominal diameter outside the predefined range to prepare a modified porous substrate with a reduced surface area attributable to the pores having a nominal diameter within the predefined range ; and (iii) contacting the surface of the modified porous substrate with a solution containing the metal.

In another embodiment, the present invention is directed to a porous substrate having a pore blocking compound within the pores of the porous substrate with a nominal diameter within a predefined range. The pore blocking compound is maintained within the pores having a nominal diameter within a predefined range, because the pore blocking compound is at least one dimension larger than the pore openings having a nominal diameter within a predefined range , or the pore blocking compound having a conformation that prevents the pore blocking compound from escaping through pore openings with a nominal diameter within the predefined range.

The present invention is directed to porous substrates treated having a pore blocking compound within the pores of the porous substrate. In one embodiment, the surface area of the micropores of the treated substrate is not greater than about 70% of the surface area of the micropores of the porous substrate before treatment. In another embodiment, the pore blocking compound is selected from the group consisting of a condensation product of a substituted cyclohexane derivative and a glycol, the condensation product of a substituted dicyclohexane derivatives and a glycol, and combinations thereof.

Other objects and characteristics will be partly apparent and partly shown below.

Brief Description of the Figures

Figures 1A-1C are graphical representations of pore blockers according to the present invention.

Figure 1D illustrates a conformational change of a pore blocker, according to the present invention.

Figure 2 describes the heat treatment of a support of a first and a second support impregnated with metal, according to the present invention.

Figures 3A / 5A and 3B / 5B show the results of transmission electron microscopy (MET) as described in the example

3.

Figures 4A and 4B provide pore volume and surface area for treated and untreated substrates as described in example 4.

Figure 5C provides porosity data for the catalysts analyzed as described in example 19.

Figure 5D provides pore volume results for the catalysts analyzed as described in example 20.

Figures 6-13 are micrographs generated by transmission electron microscopy (STEM) analysis for a carbon support and metal impregnated support as described in example 21.

Figure 14 provides the results of the scan line analysis for a metal impregnated support as described in example 21.

Figures 15 and 16 are micrographs of STEM for catalysts, as described in example 21.

Figures 17 and 18 are results of dispersive energy spectroscopy (EDS) analysis of catalysts, as described in example 21.

Figures 19-21 are micrographs of STEM for catalysts tested by reaction as described in example 21.

Figure 22 provides results of the scan line analysis for a reaction catalyst tested as described in example 21.

Figures 23 and 24 are micrographs of STEM for reaction tested catalysts as described in example 21.

Figure 25 presents the results of the scan line analysis for a reaction tested catalyst as described in example 21.

Figures 26 and 27 are EDS spectra for catalysts tested by reaction as described in example 21.

Figures 28 and 29 are TEM and STEM images for metal impregnated supports as described in example 22.

Figures 30-31, 32-33, 34-35 and 36-37 are the results of the corresponding inline scan analyzes and TEM images for substrates impregnated with metals, as described in example 22.

Figures 38 and 39 are TEM and STEM images for catalysts, as described in example 22.

Figure 40 indicates the portion of the catalyst analyzed by in-line scan analysis, as described in example 22.

Figure 41 provides the in-line scan analysis for the portion of the support identified in Figure 40.

Figure 42 indicates the portion of the catalyst analyzed by in-line scan analysis, as described in example 22.

Figure 43 provides the in-line scan analysis for the portion of the support identified in figure 40.

Figures 44 and 45 are the TEM images used in the particle size analysis, as described in example 23.

Figure 46 provides data for the particle size distribution of the analyzed catalyst as described in example 23.

Figures 47 and 48 are the TEM images used in the analysis of particle size, as described in example 23.

Figure 49 provides particle size distribution data for the analyzed catalyst as described in example 23.

Figures 50 and 51 are X-ray diffraction results for a catalyst analyzed as described in example 24.

Figures 52-55 are results of diffraction of metal nanoparticles analyzed as described in example 24.

Figures 56 and 57 provide reaction test data, as described in example 25.

Figure 58 provides reaction test data from example 26.

Figures 59-62 provide reaction test data from the example

27.

Figures 63-65 provide reaction test data from example 28.

Figures 66-68 provide reaction test data from the example

29.

Figures 69-71 provide reaction test data from the example

30.

Figures 72-78 provide reaction test data from the example

31.

Figures 79-84 provide reaction test data from the example

32.

] Figure 85 provides reaction test data from example 33. Figures 86-90 provide reaction test data from example

34.

Figures 91-95 provide reaction test data from the example

35.

Figures 96-98 provide reaction test data from the example

36.

Figure 99 provides reaction test data from example 37.

Figure 100 provides reaction test data from example 38. Figures 101 and 102 provide reaction test data from example 39.

Fig. 103 provides platinum site density data, as described in example 20.

Figure 104 provides reaction test data from example 41. Figures 105 and 106 provide reaction test data from example 42.

Figure 107 provides reaction test data from example 43.

Figure 108 provides reaction test data from example 44.

Fig. 109 provides X-Ray (XRD) results for the catalyst described in example 45.

Figures 110 and 111 XRD provide results for the catalyst described in example 46.

Fig. 111A provides platinum leach data for the catalysts described in examples 46 and 48.

Figures 112-115 provide XRD results for the catalysts described in example 50.

Fig. 116 is a micrograph of the transmission scanning electron microscopy (STEM) described in example 55.

Figures 117 and 118 are results of the energy line scan of X-ray dispersive spectroscopy (EDX) described in example 55.

Figures 119 and 120 are photomicrographs of STEM described in example 55.

Fig. 121 is a micrograph of STEM described in example 55.

Figure 122 provides in-line scanning results (EELS) of the electron energy loss spectroscopy described in example 55.

Fig. 123 is a micrograph of STEM described in example 55.

Figure 124 provides the results of inline scanning of EELS described in example 55.

Fig. 125 is a micrograph of STEM described in example 55.

Figure 126 provides the results of the EELS inline scan analysis described in example 55.

Figure 127 provides high resolution electron microscopy (HREM) photomicrographs described in example 57.

Figure 128 provides micrographs of STEM described in example 57.

Fig. 129 is a micrograph of STEM described in example 57.

Figure 130 provides the results of the EDX inline scan analysis described in example 57.

Fig. 131 is a micrograph of STEM described in example 57.

Figure 132 provides results of the in-line scan analysis

EDX described in example 57.

Fig. 133 is a photomicrograph of STEM described in example 57.

Figure 134 provides results of the scan line analysis.

EELS described in example 57.

Figures 135-137 are photomicrographs of HREM described in example 57.

Figure 138 provides XRD results described in example 57.

Fig. 139 is a micrograph of STEM described in the example

60.

Figure 140 provides results of the EELS inline scan analysis described in example 60.

Figure 141 is a micrograph of STEM described in the example

60.

Figure 142 provides the results of the EDX line scan analysis described in example 60.

Fig. 143 is a micrograph of STEM described in the example

60.

Figure 144 provides results of the EELS inline scan analysis described in example 60.

Figure 145 provides the results of the EDX line analysis described in example 60.

Fig. 146 is a micrograph of STEM described in the example

60.

Figure 147 provides the results of the EDX line analysis described in example 60.

Figure 148 provides the XRD results described in the example

60.

Figures 149 and 150 are micrographs of STEM described in example 60.

Figure 151 provides the results of the EDX line scan analysis described in example 60.

Figure 152 is a micrograph of STEM described in the example

60.

Figure 153 provides an EDX line scan analysis described in example 60.

Figures 154 and 155 provide XRD results described in example 61.

Figures 155A and 155B provide microscopy results for a finished catalyst as described in example 65.

Figures 155C - 155f provide microscopy results for a finished catalyst described in example 65.

Description of Preferred Modalities

This document describes methods of preparing the catalyst that provide improvements in the use of metal in supported metal-containing catalysts. Generally, various embodiments of the present invention include controlling and / or directing the deposition of metal on the surface of a porous substrate. The control or direction of metal deposition can be used to address one or more problems related to the preparation of catalysts containing conventional, supported metals.

For example, a potential disadvantage associated with conventional carbon and platinum catalysts is the susceptibility of relatively small particles containing platinum to leach during liquid phase catalytic oxidation reactions compared to the larger particles containing the metal. Excessive leaching of metal particles results in metal loss and represents inefficient metal use. In addition, in the case of PMIDA oxidation, it is believed that these relatively small crystallites containing platinum contribute to the formation of undesirable by-products (for example, IDA). The relatively small crystallites containing platinum are also considered more susceptible to deactivation than the larger particles (for example, by deactivating the active sites containing metal in the presence of the reaction medium and / or by coking the catalyst). It is believed that a significant portion of the relatively small particles of the metal are on the surface of the carbon support within relatively small pores and that small pores can act to capture and prevent these relatively small platinum crystallites from clumping within the particles. larger ones, which are generally more resistant to leaching and generally do not promote the formation of IDA. In addition, the metal deposited on the surface of a porous substrate within the relatively small pores is considered to be less accessible to the reactants than the metal deposited inside larger pores and thus contributes less to the activity of the catalyst.

Various methods described here for directing and / or controlling metal deposition generally involve treating porous substrates by placing or introducing one or more pore blocking compounds within the pores of a predefined size range. The methods described here can be used to selectively block pores within a given size domain without significantly affecting other pores of the substrate, in order to provide an advantageous catalytic surface area. As detailed in this document, including the context, various embodiments of the present invention provide a porous substrate including a pore blocking compound arranged and preferably kept relatively within the small pores (e.g., micropores or pores having a nominal diameter of less than about 20Δ). The presence of the pore blocking compound within the pores of the substrate can be indicated by a reduced ratio of surface area attributable to relatively small pores (for example, a reduced ratio of microporous surface area) and / or by a reduced contribution to porosity of the substrate through relatively small pores. It is believed that the presence of pore blocking compounds within the micropores of the treated substrate reduces and, preferably, substantially prevents the deposition of metal on the surface of the substrate within these pores, thus directing the deposition of metal to other surfaces of the substrate and inside larger pores.

The presence of the pore blocker, therefore, is currently considered to reduce the formation of small metal crystallites within the micropores that are resistant to agglomeration, easily leached and / or deactivated, and represent the inefficient use of the metal.

In addition to, or separated from, the effect of controlling or directing the site of metal deposition (for example, by the disposition inside or introduction of a pore blocking compound in the pores of the substrate), the form of metal deposition can promote the more efficient metal as well. For example, various catalysts described herein include and / or are prepared from a support having one or more regions of a first metal on the surface of the support, and a second metal on the surface of one or more regions of the first metal.

The first metal is selected to have a greater electropositivity than the second metal and the second metal is deposited on the surface of one or more regions of the first metal by displacing the first metal from one or more regions on the surface of the support. More particularly, the second metal can be deposited by atom-to-atom substitution close to the first metal by the second metal. It is currently believed that the deposition of metal in this way promotes the formation of a relatively thin layer comprising atoms of the second metal and may, in fact, form a monolayer close to atoms of the second metal deposited on the surface of the regions of the first metal (for example, a layer of atoms of the second metal on the surface of one or more regions of the first metal is no more than about 3 atoms thick). The heating of the carbon support having the first and second metals in the same metal forms metal particles comprising the first and the second metal. The formed metal particles contain the second metal in a form that represents the most efficient use of the second metal. For example, the composition of a significant fraction of the metal particles is generally rich in the content of the first metal, thus providing a relatively low ratio of unexposed second metal along the particles (for example, a bimetallic alloy rich in the first metal). Additionally or alternatively, the metal particles formed upon subsequent heating may have a relatively thin shell comprising the second metal (for example, a layer of no more than about 3 atoms in thickness), at least partially around a composite core predominantly of the first metal.

I. Treatment of Porous Substrates

The arrangement within and / or the introduction of a pore blocking agent or compound (also referred to herein as a pore blocker) into the pores of a porous substrate generally comprises contacting the substrate with the agent or compound, or a precursor (or precursors) ) the same. In one embodiment, the pore blocking compound is preferably kept within the pores of the substrate within a selected size domain (for example, micropores), by virtue of having at least one dimension larger than the pore openings, thus preventing that the agent leaves the selected pores. In various embodiments, the pore blocking agent can be formed from one or more precursors of pore blocking agents introduced into the pore substrate. Additionally or alternatively, and regardless of whether the pore blocking agent is introduced into the pores or formed in situ (i.e., formed from one or more precursors of agents introduced into the pores), the agent can be maintained inside the pores of the substrate within a selected size domain due to a conformational change induced in the pore blocking agent, such that the pore blocking agent is dimensionally prevented from leaving the selected pore. A conformational change in the pore blocking agent can be induced within the selected pores due to interactions between the pore blocking agent and the pore walls. According to one embodiment, a pore blocking agent is disposed within and preferably kept within the pores of the porous substrate to produce a treated substrate for metal deposition exhibiting a lower microporous surface area ratio.

It should be understood that reference to one or more precursors includes compositions that ultimately function as a pore blocking agent upon entry into the pores (for example, by virtue of at least one dimension of the compound and / or by virtue of a conformational change in the compound after entering the pores). In addition or alternatively, the reference to one or more precursors may refer to one or more compounds that combine or react to form the pore blocking agent, once disposed within and / or introduced into the pores of the substrate. Regardless of whether a compound that ultimately functions as a pore blocker is introduced or disposed within the pores of the substrate, or whether the components that combine to form the pore blocker are introduced or disposed within the pores, the mechanism by which the pore blocker is considered to function (that is, by virtue of having at least one dimension larger than the pore openings, initially or after a conformational change) is the same.

In various embodiments, the pore blocker comprises a compound having at least one dimension such that, upon entry into the pores, the pore blocker is preferably maintained within these pores falling within a selected size domain. Notably, it is necessary to understand that the pore blocker, likewise, usually has at least one dimension that allows entry into the pores, but currently it is believed that the pore blocker normally assumes an orientation and / or conformation inside the pores such that the dimension larger than the opening of the pores prevents the pore blocking compound from leaving the pore.

As noted above, according to one embodiment, the pore blocker is preferably kept within the substrate micropores. However, this does not exclude the pore blocker or precursor (s) from it, from also entering the pores of a size that is not within this predefined range through contact with the porous substrate. For example, the pore blocker may enter pores having a nominal diameter greater than about 20 Â (for example, pores having a nominal diameter of about 20 Â, about 3000 Â, commonly referred to as meso- and macropores), but the pore blocker tends to subsequently come out and is not preferably kept within those pores, although the pore blocking agent may remain in a smaller portion of the pores outside the micropore range.

A. Porous substrate

Generally, the porous substrate or support structure for the active phase containing catalytic metals can comprise any material suitable for the deposition of one or more metals therein. Preferably, the porous substrate is in the form of a carbon support. In general, the carbon supports used in the present invention are well known in the art, including, for example, those described in U.S. Patent No. 6,417,133 to Ebner et al. and by Wan et al. in WO 2006/031938 (the total contents of which are hereby incorporated by reference for all relevant purposes). Activated non-graphitized carbon supports are preferred for the noble metal in carbon catalysts used for oxidizing PMIDA and providing catalyst with robust mechanical integrity and high surface area for the active phase containing metal. However, activated non-graphitized carbon supports are not necessarily preferred in all cases and it should be understood that catalysts suitable for various other applications can be prepared using carbon supports that are not activated and / or non-graphitized. In a number of particularly preferred embodiments, the supports are in the form of particles (e.g., powders).

In several preferred embodiments (for example, catalysts used for the oxidation of PMIDA), the carbon support contains a relatively low ratio of functional groups containing oxygen (for example, carboxylic acids, ethers, alcohols, aldehydes, lactones, ketones, amines esters , oxides, and amides). These functional groups can increase the leaching of noble metals and potentially increase the agglomeration of noble metals and the growth of particles during liquid phase oxidation reactions and thus reduce the catalyst's ability to oxidize oxidizable substrates (eg PMIDA and / or formaldehyde). As used here, an oxygen-containing functional group is on the surface of the carbon support if it is attached to a carbon support atom and is able to interact chemically or physically with the compositions within the reaction mixture, or with the metal atoms deposited on the carbon support. As described in US Patent No. 6,417,133 and by Wan et al. in WO 2006/031938, many of the oxygen-containing functional groups, which reduce the resistance of noble metals to leaching and sintering and reduce the activity of the catalyst to desorb from the carbon support as carbon monoxide when the catalyst is heated to an elevated temperature (eg 900 ° C) in an inert atmosphere (eg helium or argon). Thus, measuring the amount of CO desorption from a fresh catalyst (ie a catalyst that has not previously been used in a liquid phase oxidation reaction) at high temperatures is a method that can be used to analyze the catalyst surface to prevent the retention of noble metals and the maintenance of catalytic activity. One way to measure CO desorption is by using inline mass spectroscopy thermogravimetric analysis (TGA-MS). Preferably, no more than about 1.2 mmol of carbon monoxide per gram of catalyst will desorb the catalyst of the present invention, when a dry, fresh sample of the catalyst, after having been heated to a temperature of about 500 ° C by about an hour in a hydrogen atmosphere and before being exposed to an oxidizer after heating in the hydrogen atmosphere, it is heated in a helium atmosphere that is subjected to a temperature that is increased from about 20 ° C to about 900 ° C at about 10 ° C per minute, and then kept constant at about 900 ° C for approximately 30 minutes. More preferably, no more than about 0.7 mmol of carbon monoxide per gram of fresh catalyst desorbs under these conditions, even more preferably no more than about 0.5 mmol of carbon monoxide per gram of fresh catalyst desorbs, and more preferably not more than about 0.3 mmol of carbon monoxide per gram of fresh catalyst desorbs. A catalyst is considered to be dry when the catalyst has a unit content of less than about 1% by weight. Typically, a catalyst can be dried by placing it in a N ₂ purged vacuum of about 25 inches Hg and a temperature of about 120 ° C for about 16 hours.

As further described in U.S. Patent No. 6,417,133 and by Wan et al. in WO 2006/031938, measuring the number of oxygen atoms on the surface of a fresh catalyst support is another method for analyzing the catalyst to prevent the retention of noble metals and the maintenance of catalytic activity. Using, for example, photoelectron x-ray spectroscopy, a surface layer of the support that is about 50 Δ thick is analyzed. Preferably, this analysis for a support suitable for use in connection with the oxidation catalysts described herein indicates a ratio of carbon atoms to oxygen atoms on the surface of the support of at least about 20: 1. More preferably, the ratio is at least about 30: 1, even more preferably at least about 40: 1, even more preferably at least about 50: 1, and most preferably at least about 60: 1 . In addition, the ratio of oxygen atoms to metal atoms on the surface is preferably less than about 8: 1. More preferably, the ratio is less than about 7: 1, more preferably less than about 6: 1, and even more preferably less than about 5: 1.

Typically, a support that is in the form of particulates can include a wide particle size distribution. For powders, preferably at least about 95% of the particles are about 2 to about 300 pm in their largest dimension, more preferably at least about 98% of the particles are about 2 to about 200 pm in their largest dimension, and more preferably about 99% of the particles are about 2 to about 150 pm in their largest dimension, with about 95% of the particles being about 3 to about 100 pm in their largest dimension. Particles larger than about 200 pm in their largest dimension tend to fracture into superfine particles (ie less than 2 pm in their largest dimension), which can be more difficult to recover.

In the following discussion, specific surface areas of carbon catalysts and supports are generally presented in terms of the well-known Langmuir method using N ₂ . It must be understood that these values generally correspond to those measured by the Brunauer-Emmett-Teller (BET) method also known, using _N2 .

The specific surface area of the carbon support before any treatment (for example, disposition or introduction of a pore blocking compound within the pores of a substrate), according to the present invention is, in general, at least about 500 m ² / g, at least about 750 m ² / g, at least about 1000 m ² / g, or at least about 1250 m ² / g. Typically, the specific surface area of the carbon support is from about 10 to about 3000 m ² / g, more generally from about 500 to about 2100 m ² / g, and even more typically from about 750 to about 1900 m ² / g or from about 1000 to 1900 m ² / g. In certain embodiments, the preferred specific area is about 1000 to about 1700 m ² / g, from 1000 to about 1500 m ² / g, from about 1100 to about 1500 m ² / g, from about 1250 at about 1500 m ² / g, from about 1200 to about 1400 m ² / g, or about 1400 m ² / g. In addition, according to the present invention, the porous carbon support generally has a pore volume of at least about 0.1 ml / g, at least about 0.2 ml / g, or at least about 0.4 ml / g. Typically, the porous carbon support has a pore volume of about 0.1 to about 2.5 ml / g, more typically from about 0.2 to about 2.0 ml / g, and even more typically , from about 0.4 to about 1.5 ml / g.

It should be noted that the present discussion focuses on pore blocking treatment to reduce the surface area of micropores of porous carbon substrates or supports for use in catalysts containing noble metal suitable for use in PMIDA oxidation. However, it must be understood that methods for treating a porous substrate by introducing a pore blocking compound, as described herein, are generally applicable to, preferably, blocking other pore size domains, other types of catalyst supports porous and / or porous carbon substrates used as supports for metals other than noble metals. For example, the methods of the present invention are suitable for the treatment of porous Raney metals or alloys often referred to as sponges, such as those described in US Patent No. 7,329,778 to Morgenstern et al. and used as supports for copper-containing catalysts used in the dehydrogenation of primary amino alcohols. As a further example, the methods of the present invention are also suitable for the treatment of porous supports other than carbon, for example, silicon dioxide (SiO ₂ ), aluminum oxide (AI2O3), zirconium oxide (ZrO ₃ ), titanium oxide (TiO ₂ ), and combinations thereof.

B. Pore Blocking

According to the present invention, the pore blocker used to selectively block micropores can be selected from a variety of compounds including, for example, various sugars (for example, sucrose), compounds containing 5- or 6-ring members (for example, 1,3- and 1,4-disubstituted cyclohexanes), and combinations thereof. Compounds suitable for use in connection with selective blocking of micropores include 1,4-cyclohexanedimethanol- (1,4-CHDM), 1,4-bis cyclohexanedione (ethylene ketal), 1,3- or 1,4- cyclohexanedicarboxylic, 1,4-cyclohexanedione monoethylene acetal, and combinations thereof.

In various embodiments, the pore blocker may comprise the product of a reaction (for example, a condensation reaction) between one or more precursors of pore blocking compounds. Once formed, the resulting pore blocking compound can preferably be kept within the selected pores of the substrate, by virtue of having at least one dimension that prevents the pore blocking compound from escaping through the pores.

For example, it has been observed that the coupling product of a cyclohexane derivative and a glycol can be used as a pore blocking agent of the micropores for the particulate carbon substrates used to support a noble metal or other metal catalyst. More particularly, the pore blocking agent may be the coupling product of a disubstituted, tri-substituted or tetra-substituted cyclohexane derivative. In particular, cyclohexane derivatives can be selected from the group consisting of 1,4-cyclohexanedione 1,3-cyclohexanedione 1,4-cyclohexanobis (methylamine), and combinations thereof. Glycol is generally selected from the group consisting of ethylene glycol, propylene glycol, and combinations thereof.

Generally, the substrate is contacted with a liquid comprising the pore blocking agent or one or more precursor (s) of the pore blocking agent. Normally, the substrate to be treated is contacted with a mixture or solution that comprises one or more pore blocking compounds or precursor (s) dispersed or dissolved in a medium that contacts the liquid (for example, deionized water). For example, the substrate can be contacted with a mixture or solution that includes a cyclohexane derivative and a glycol, or a medium that contacts the liquid consisting essentially of cyclohexane and glycol derivatives. The substrate can also be contacted sequentially with liquids or liquid medium comprising one or more of the precursors. The composition of the liquid including the pore blocking agent or a precursor (s) thereof contacted with the porous substrate is not strictly critical and can be easily selected and / or optimized by one skilled in the art.

As noted, regardless of whether a compound that ultimately functions as a pore blocker is introduced into the pores of the substrate or precursors that form the blocking compound are introduced into the substrate, the pore blockers can preferably be kept within the pores of the selected substrate i

(for example, micropores), due to the conformational arrangement assumed by the pore blocking agent, once disposed or formed inside the pores. For example, it is currently believed that several pore blocker molecules are transformed from a more linear chair shape to a more bulky boat shape, which leads to the trapping of compounds within the micropores. In particular, it is currently believed that several pore blocking agents including a hydrophilic end group will favor a boat conformation within the micropore (s) of a porous carbon support, due to the nature of the carbon support (or i.e., the conformation of the boat will be favored by a pore blocking compound having groups of hydrophilic ends, due to the relatively hydrophobic nature of the surface of the carbon support), examples of pore blocking compounds, including a hydrophilic end group include 1,415 acid cyclohexanedicarboxylic and 1,4-hexanedimethanol (CHDM).

A conformational change of a pore blocker can also be promoted or induced by manipulating the liquid medium comprising the pore blocking agent in contact with the substrate including, for example, adjusting the pH and / or adjusting the temperature of the liquid medium.

Figures 1A-1C provide graphical representations of preformed pore blockers and pore blocker molecules formed from precursors within the pore (ie coupling in situ) that have undergone a conformational change within the pores to selectively block or plug the smaller pores. The conformational change of a cyclohexane pore blocker is shown, in general, in Figure 1 D. These representations are for illustrative purposes and are not intended to limit the present invention.

As noted, contact of the substrate with precursors or blocking agents is believed to result in the pore blocking agent being introduced or disposed within the micropores of the substrate, and within larger pores outside this predefined range. To provide a treated substrate in which micropores within the predefined range are preferably blocked, the substrate is subsequently contacted with a washing liquid to remove the pore blocking agent outside the micropore domain (i.e., those pores in which the agent pore blocker will not preferably be maintained because the agent is at least larger than the opening of the pores). The exact composition of the washing liquid and the manner of its contact with the substrate are not strictly critical, but the substrate can be contacted properly with deionized water for this purpose.

C, Treated Substrates

As noted, the substrate treatment method of the present invention is suitable for introducing a pore blocking agent into the pores of the porous substrate (for example, a particulate carbon support) and, preferably, maintaining the pore blocking agent in the micropores . The preferential retention of the pore blocking agent inside the micropores can be represented by the proportion of micropores in which the agent is kept. Typically, the pore blocking compound maintains at least about 2%, at least about 5%, at least about 10% or at least about 20% of the micropores, based on the total number of micropores in the substrate.

The preferential retention of the pore blocking compound within the micropores can also be indicated by the treated surface area of the substrate provided by micropores and provided by the larger pores. It is believed that the presence of the pore blocking compound within the micropores will cause at least a portion of these blocked pores to appear as a non-porous portion of the treated substrate during surface area measurement methods (for example, the measurement of known Langmuir surface area), thereby reducing the proportion of surface area that could be attributable to micropores if they were not blocked. This preferential blocking of the target pores results in a reduction in the surface area provided by the micropores (ie, the surface area of the micropores). For example, in various embodiments, the surface area of the micropores of the treated substrate is generally no more than about 70%, no more than about 60%, or more than about 50% of the surface area of the micropores of the substrate before treatment by contact with the pore blocker. Preferably, the surface area of the micropores of the treated substrate is not more than about 40%, more preferably not more than about 30%, and even more preferably not more than about 20% of the surface area of the micropores of the substrate before the treatment.

D. Methods for the Preparation of Catalysts Using Substrates

Treaties

As detailed here, catalysts can be prepared by a process, in general, comprising depositing one or more noble metals and, optionally, one or more metals from the promoter on the surface of a treated substrate (i.e. blocked pores) such as a porous carbon support, and heating the carbon support with the noble metal and optional promoter (s) deposited therein in a non-oxidizing environment.

Noble metals are usually selected from the group consisting of platinum, palladium, ruthenium, rhodium, iridium, silver, osmium, gold, and combinations thereof. In various preferred embodiments, the noble metal comprises platinum and / or palladium. In even more preferred forms, the noble metal is platinum. One or more metals of the promoter is generally selected from the group consisting of tin, cadmium, magnesium, manganese, nickel, aluminum, cobalt, bismuth, lead, titanium, antimony, selenium, iron, rhenium, zinc, cerium, zirconium, tellurium, germanium and combinations thereof on a porous substrate surface and / or on a noble metal surface.

Noble metal can be deposited in accordance with conventional methods known in the art, including, for example, liquid phase deposition methods, such as reactive deposition techniques (for example, deposition by reducing noble metal compounds and deposition through the hydrolysis of noble metal compounds), ion exchange techniques, impregnation with excess solution, and impregnation of incipient dryness, vapor phase methods, such as physical deposition and chemical deposition; precipitation; electrochemical deposition, and autocatalytic deposition, as described in U.S. Patent No.

6,417,133 and by Wan et al. in international publication No. WO 2006/031938.

In various preferred embodiments, the noble metal is deposited via a reactive deposition technique comprising contacting the carbon support with a solution comprising a salt of the noble metal, and then hydrolysis of the salt. An example of a suitable relatively inexpensive platinum salt is hexachloroplatinic acid (H2PtCI ₆ ).

A promoter (s) can be deposited on the treated carbon support surface before, simultaneously with, or after the deposition of the noble metal on the surface. Methods for depositing a promoter metal are generally known in the art, and include the methods noted above in relation to the deposition of the noble metal.

After the carbon support has been impregnated with the noble metal (s) and the optional promoter (s), the catalyst surface is preferably heated to high temperatures, for example, in a heat treatment or calcination operation. For example, calcination can be carried out by placing the catalyst in an oven (for example, rotary kilns, tunnel kilns, and vertical calciners) through which a heat-treating atmosphere is passed.

Generally, the surface of the treated support impregnated with one or more metal is heated to a temperature of at least about 700 ° C, at least about 800 ° C, at least about 850 ° C, at least about 900 ° C , or at least about 950 ° C. Typically, the support is impregnated with metal heated to a temperature of about 800 ° C to about 1200 ° C, preferably from about 850 ° C to about

1200 ° C, more preferably from about 900 ° C to about 1200 ° C, even more preferably from about 900 ° C to about 1000 ° C, and especially from about 925 ° C to about 975 ° C .

The length of time that the impregnated support is subjected to high temperatures (including the time that the support is heated to the maximum temperature) is not strictly critical. Typically, in the commercial scale apparatus, the metal impregnated support is heated to a maximum heat treatment temperature for at least about 10 minutes (for example, at least about 30 minutes).

Preferably, the metal impregnated support is heated in a non-oxidizing environment. The non-oxidizing environment can comprise or consist essentially of inert gases such as N ₂ and noble gases (for example, argon, helium), or mixtures thereof. In certain embodiments, the non-oxidizing environment comprises a reducing environment and includes a reducing agent in a gas phase such as, for example, hydrogen, carbon monoxide, or combinations thereof. The non-oxidizing environment in which the catalyst is heated can include other components, such as ammonia, water vapor, and / or a compound comprising oxygen as described, for example, by Wan et al. in international publication No. WO 2006/031938. In one embodiment, the heat treatment after deposition of the metal preferably comprises reduction in the gas phase at high temperature to remove the functional groups containing oxygen from the surface of the catalyst, thus reaching a catalyst that exhibits the desorption of carbon monoxide and / or characteristics of the surface ratio of the oxygen atom to the carbon atom, as described in Ebner et al. US Patent No. 6,417,133.

In several preferred embodiments, the noble metal is bonded with at least one promoter to form alloy metal particles. For example, the noble metal particles on a carbon support surface can comprise noble metal atoms bonded with the atoms of the promoter metal. In several other preferred embodiments, the noble metal is bonded with two promoters (for example, iron and cobalt). Catalysts comprising a noble metal bound with one or more promoters often exhibit greater resistance to metal leaching and greater stability (for example, from cycle to cycle) with respect to formaldehyde and formic acid oxidation. It is to be understood that the term alloy, as used here generally encompasses any metal particle comprising a noble metal and at least one promoter (for example, intermetallic compounds, substitutional alloys, multiphase alloys, separate alloys and interstitial alloys, as described by Wan et al. In international publication No. WO 2006/031938).

Submitting the metal-impregnated support to a heat treatment generally provides agglomeration and / or sintering of the metal particles on the support surface. The use of substrates treated with blocked micropores results in impregnated substrates having a reduced percentage of particles containing relatively small metals on the support surface within the micropore domain, which are generally more susceptible to leaching and / or deactivation compared to particles containing metals larger size nobles. Additionally or alternatively, particles containing metals on the substrate surface outside the micropore domain are generally more accessible to the reagents. By virtue of one or both of these effects, the treated substrates of the present invention are considered to provide the most efficient use of the metal (e.g., an increase in the effective catalytic metal surface per unit weight) in the catalyst.

It should be noted that the persistence of the pore blockers in the treated substrate after heat treatment of post-metal deposition is not essential to provide the advantages noted above. In fact, it is currently believed that the pore blocker is more likely to decompose and / or removed from the substrate surface during calcination. But even today it is believed that one or more of the advantages noted above are achieved provided that the pore blocker is preferably maintained with the selected pores on the support surface during the deposition of the metal, in order to promote the dispersion of the desired metal.

E. Catalysts Prepared Using Treated Substrates

The substrates treated in accordance with the present method (i.e., blocked pore substrates) can be used as supports for catalysts containing metals including, for example, catalysts including one or more noble metals (for example, a noble metal such as platinum) deposited on a particulate carbon support. In addition, noble metal-containing catalysts prepared using the substrates treated by the present invention can include one or more promoter (s) and can be prepared to exhibit one or more of the characteristics described, for example, in US Patent No. 6,417. 133, International Publication No. WO 2006/031938 and US Patent No. 6,956,005, all of which are incorporated herein by reference for all relevant purposes.

Generally, the noble metal constitutes less than about 8% by weight of the catalyst, usually less than about 7% by weight of the catalyst, more typically less than about 6% by weight of the catalyst. In various embodiments, the noble metal normally constitutes from about 1% to about 8% by weight of the catalyst, more typically from about 2% to about 7% by weight of the catalyst and, even more typically, about 3 % to about 6% by weight of the catalyst.

As noted, the particulate carbon supports treated in accordance with the present invention to preferably block micropores provide the most efficient use of the metal. Thus, effective catalysts can be prepared so that they contain the noble metal in an amount below the limits noted above and / or at the lower limit or near the lower limit of one or more of the ranges noted above. For example, in various embodiments, the noble metal constitutes less than 5% by weight of the catalyst, less than about 4% by weight of the catalyst, or even less than about 3% by weight of the catalyst. For example, in various embodiments, the noble metal typically constitutes from about 1% to about 5% by weight of the catalyst, more typically from about 1.5% to about 4% by weight of the catalyst and, even more typically, from about 2% to about 3% by weight of the catalyst. However, it should be understood that the present invention does not require a treated substrate to be used for the preparation of a noble metal-containing catalyst, including a reduced proportion of noble metal compared to conventional catalysts. That is, the preparation of a catalyst including a treated porous substrate that provides the most efficient use of metals in conventional noble metal fillers in the same way represents an advance in the technique (for example, the treated substrates of the present invention are considered to provide a reduced proportion of the relatively small metal particles that are susceptible to leaching and represent inefficient use of metal, thus contributing to improvements in catalytic activity and reduced formation of unwanted by-products (eg IDA)).

Generally, according to some modalities, at least one promoter (for example, iron) constitutes less than about 2% by weight of the catalyst, less than about 1.5% by weight of the catalyst, less than about 1% in weight of the catalyst, less than about 0.5% by weight of the catalyst, or about 0.4% by weight of the catalyst. Typically, at least one promoter constitutes less than 1% by weight of the catalyst, preferably from about 0.25% to about 0.75% by weight of the catalyst, and preferably from about 0.25% to about 0.6% by weight of the catalyst. In several preferred embodiments, the catalyst includes iron as a promoter. Additionally or alternatively, the catalyst includes cobalt as a promoter.

In a number of particularly preferred embodiments, the catalyst comprises both iron and cobalt promoters. Use of iron and cobalt generally provides benefits associated with the use of iron (for example, the activity and stability towards oxidation of formaldehyde and formic acid). However, compared to the presence of iron individually as a promoter, the presence of cobalt tends to reduce the formation of certain by-products during the oxidation of a substrate of

PMIDA (for example, IDA). In addition, the formation of IDA is considered to be directly related to the total iron content of the catalyst. Thus, in various types of cast iron / cobalt copromotor, the iron content is essentially replaced by cobalt to reduce the formation of AID and other by-products, while, however, it provides sufficient activity aimed at the oxidation of formaldehyde and formic acid. For example, compared to a platinum carbon catalyst that contains 0.5% by weight of iron in the absence of cobalt, a similar catalyst containing 0.25% by weight of iron and 0.25% by weight of cobalt generally provides comparable activity for the oxidation of PMIDA, formaldehyde and formic acid, by minimizing the formation of by-products.

In iron / cobalt co-promoter modalities, the amount of each promoter on the surface of the carbon support (either associated with the carbon surface itself, noble metal, or a combination thereof) is typically at least about 0, 05% by weight, at least about 0.1% by weight or at least about 0.2% by weight. In addition, the amount of iron on the surface of the carbon support is usually about 0.1 to about 4% by weight of the catalyst, preferably from about 0.1 to about 2% by weight of the catalyst, more preferably from about 0.1 to about 1% by weight of the catalyst and even more preferably from about 0.1 to about 0.5% by weight of the catalyst. Likewise, the amount of cobalt on the surface of the carbon support is usually from about 0.1 to about 4% by weight of the catalyst, preferably from about 0.1 to about 2% by weight of the catalyst, preferably more than about 0.2 to about 1% by weight of the catalyst and, even more preferably, from about 0.2 to about 0.5% by weight of the catalyst. In such an embodiment, the weight ratio of iron to cobalt in the catalyst is generally about 0.1: 1 to about 1.5: 1 and preferably about 0.2: 1 to about 1: 1. For example, the catalyst can comprise about 0.1% by weight of iron and about 0.4% by weight of cobalt or about 0.2% by weight of iron and about 0.2% by weight of cobalt .

As understood by those skilled in the art, the metal content of catalysts can be freely controlled within the ranges described in this document (for example, by adjusting the concentration and relative proportion of the metal source (s) used in a reactive deposition bath in liquid phase).

II. Catalysts Containing First and Second Metals

Several preferred embodiments of the present invention are directed to catalysts that comprise and / or are prepared from a porous substrate or support having one or more regions of a first metal on its surface, and a second metal on the surface of one or more regions of the first metal. In such modalities, the first metal is selected to have a greater electropositivity than the electropositivity of the second metal (that is, the first metal is greater than the second metal in the electromotive series). The oxidation of the first metal provides electrons to reduce the second metal ions present in the deposition bath, thereby depositing atoms of the second metal on the surface of one or more regions of the first metal. The oxidation of the first metal and the reduction and deposition of the second metal occur substantially simultaneously and the atoms of the second metal are deposited on the surface of one or more regions of the first metal by displacing the ions of the first metal from one or more regions in the deposition bath. The deposition of metal in this way can be referred to as spontaneous or deposition of redox detachment. (See, for example, U.S. Patent No. 6,670,301 to Adzic et al. And U.S. Patent Nos. 6,376,708, 6,706,662 and 7,329,778 to Morgenstern et al.). Preferably, the first sacrifice metal is less expensive than the second metal.

As detailed in this document, the deposition of the second metal by detaching the deposition is preferably conducted and controlled in a manner that provides preferential deposition of the second metal on the surface of one or more regions of the first metal. That is, the second metal is preferably deposited on the surface of the region (s) of the first metal by the deposition of detachment on the deposition of the second metal on the surface of the support and / or deposition of the second metal on the surface of the second metal already deposited .

Without being linked to a particular theory, it is currently believed that the ion source of the second metal can promote the preferential deposition of the second metal in one or more regions of the first metal. More particularly, it is currently believed that sources of the second metal that supply the ions of the second metal in low numbers of oxidation (eg +2) provide slower, more controlled deposition of the metal compared to sources that supply ions of noble metals with higher oxidation numbers (eg +4). The ions of the second metal with these higher oxidation numbers are considered to be more easily reduced in the presence of electrons generated by the oxidation of the first metal, which provides a greater driving force for the deposition of the second metal. This greater driving force is believed to increase the deposition rate of the second metal which, in turn, promotes less discrimination deposition of the second metal. More particularly, it is believed that the greatest driving force for the deposition of the ions of the second metal promotes the deposition of atoms of the second metal on the support and / or on the surface of the atoms of the second metal already deposited. Thus, it is currently believed that, as the oxidation state of the ions of the second metal decreases, the preferential deposition (for example, selective) of the noble metal directed to one or more regions of the first metal by the displacement of atoms of the first metal metal on the deposition on the carbon support and / or atoms of the second metal already deposited generally increases.

In addition, it is currently believed that the deposition of atoms of the second metal using sources that supply ions with relatively low oxidation numbers proceeds in a manner that generally reduces the complexity of the displacement deposition process to promote the desired preferred deposition of the second metal directed in the regions of the first metal. For example, displacement deposition using sources that provide ions of the second metal at relatively low oxidation numbers proceeds quickly in the absence of precise control of the concentration of the source of the second metal and / or deposition time.

According to the present invention, it is currently believed that a significant, if not substantially all, fraction of the second metal deposited by the controlled displacement of a first metal provides domains or regions on the surface of one or more regions of the first metal characterized as comprising a relatively thin layer of atoms of the second metal (for example, no more than about 5 atoms in thickness, or no more than about 3 atoms in thickness), instead of agglomerating to form particles containing metal. In certain preferred embodiments, the preparation of the catalyst by the present method can provide a monolayer close to the second metal (for example, a layer of atoms of the second metal of no more than about 3 atoms in thickness, no more than about 2 atoms thick, and preferably about 1 to about 2 atoms thick).

Furthermore, according to the present invention, it is currently believed that the deposition of the second metal by displacing atoms of the first metal from one or more regions of the first metal provides a structure (for example, a catalyst precursor structure) that , after heat treatment at high temperatures, provides metal particles that include the second metal in a form that represents the most efficient use of the second metal. In various embodiments, metal particles are typically rich in the first metal (that is, they contain an excess of atoms of the first metal over the atoms of the second metal) and the particles are currently believed to include one or more bimetallic alloys. In contrast, conventional noble metal containing catalysts typically include particles comprising an atomic excess of noble metal atoms. In this way, it is believed that the particles rich in the first metal include the noble metal (that is, the second) in a way that represents a reduced proportion of the noble metal distributed throughout the particle and therefore represents unexposed reduction and, noble metal atoms not potentially used throughout the particle structure. But an excess of first metal is not necessary to provide an improvement in the use of the metal. However, as the proportion of the first metal to the second metal is greater, improvements in the use of the second metal can be achieved. Thus, several embodiments of the present invention contemplate the selection of combinations of the first and the second metal, which are favorable to the formation of alloys, which include at least an equivalent atomic ratio of the first metal (Mi) to the second metal (M ₂ ). More particularly, in various modalities, there is a preference for selecting combinations of first and second metals that provide bimetallic alloys of the first and second metals, Mi _x M ₂ y, where the atomic ratio of x: y is greater than or equal to 1. In addition, according to these and several other preferred embodiments, metal particles include bimetallic alloys where the atomic ratio of x: y is greater than about 2, or greater than about 3. For example, in the case of copper and platinum metals as first and second metals, respectively, the metal particles on the surface of the support may include CuPt and / or bimetallic Cu ₃ Pt alloys. As an additional example, in the case of tin and platinum as first and second metals, respectively, at least some of the metal particles can include Pt ₂ Sn ₃ , PtSn ₂ and / or bimetallic PtSn ₄ alloys. In the case of iron and platinum as first and second metals, respectively, the metal particles on the surface of the support may include, for example, Fe ₃ Pt, FePt, Feo, ₇₅ Pto, 25.

Additionally or alternatively, it is also currently believed that at least some of the supported metal particles produced by calcining a catalyst precursor structure prepared by displacement by deposition of a noble metal (ie second) as detailed here include a relatively thin layer. thin or shell comprising atoms of the second metal (e.g., a layer of atoms of the second metal of no more than about 3 atoms in thickness), at least partially around a core comprising the first metal. The core generally comprises a relatively high concentration of the first metal (for example, greater than about 50 percent atoms). The combination of a first metal-rich core and a shell containing the second metal provides a relatively low proportion of the second unexposed metal and therefore offers improvements in the surface area of the exposed metal per unit weight of the metal. It is currently believed that particles that exhibit a shell-core arrangement can in general provide a greater improvement in the use of the second metal over conventional noble metal supported catalysts compared to particles, in general, characterized as being rich in the first metal (ie , a greater increase in the surface area of the second exposed metal per unit weight of the second metal). Thus, as the fraction of core-shell particles on the support surface increases, the use of the metal in the catalyst also increases. Thus, in various preferred embodiments, the catalyst includes a predominant fraction of metal particles exhibiting a core-shell arrangement. However, it should be noted that improvements in the use of metals are still provided due to the presence of metal particles, in general, rich in the content of the first metal, regardless of the presence of particles characterized as exhibiting a core- bark.

It should be noted that the reference to a porous substrate such as a carbon support having the first and the second metal deposited on it (ie, a first and a second support containing metal) as a catalyst precursor structure does not exclude the catalytic activity of these impregnated substrates in the absence of subsequent heat treatment. In fact, experimental evidence indicates that the support impregnated with metal prepared in this way can function as effective catalysts. Thus, elsewhere here (including the claims) porous substrates with a first metal deposited on them (for example, a support impregnated with the first metal) are also referred to as catalyst precursor structures. But in several preferred embodiments, the support impregnated with the first and the second metal is heated to elevated temperatures to provide the catalyst (sometimes referred to here as a finished catalyst).

Experimental evidence indicates that catalysts (i.e., both catalyst precursor structures and finished catalysts), prepared as detailed here using a noble metal and a first sacrificial metal layer, are at least as active as conventional noble metal. on carbon catalysts on a metal weight basis per unit. Without being bound by a particular theory, it is currently believed that the active sites or domains of the second metal provided by the method of the present invention provide an increase in the surface area of the catalyst per unit weight of the metal compared to catalysts containing conventional metals, prepared by methods that do not include displacement deposition of the second metal in one or more regions of a first sacrifice metal.

Conventional noble metal carbon catalysts generally include particles containing noble metal on the support surface, formed by agglomerating and / or sintering noble metal atoms and / or particles containing noble metal. This agglomeration usually occurs during the post-deposition heat treatment of a support impregnated with noble metal at relatively high temperatures. The metal particles of conventional noble metal catalysts formed by the agglomeration of metal deposited on the surface of a support, generally include the noble metal distributed throughout the entire particle (for example, the particles have a relatively constant composition profile of noble metals in concentration). Particle stability (eg resistance to reaction conditions under deactivation and / or leaching) generally increases with increasing particle size, but the catalytic surface area of the exposed metal, per unit weight of metal, typically decreases in larger particles . Thus, despite the increased stability, an abundance of particles containing relatively large noble metals and the smaller surface area of catalytic metal served per unit weight of the metal represents less efficient use of metals. Advantageously, particles rich in the first metal and / or metal particles comprising a shell containing noble metal (i.e., second) and a core containing the first metal prepared according to the various embodiments of the present invention generally represent the most common use. efficient metal. For example, as noted, particles rich in the first metal are believed to include the second metal in a form (e.g., a bimetallic alloy including an atomic excess of the first metal) that provides a reduced proportion of the second non-exposed metal.

Additionally or alternatively, and as detailed elsewhere, larger, more stable metal particles in accordance with the present invention are not associated with an unacceptable decrease in the effective surface area of the second catalytic metal since an increase in particle size is usually associated with an increase in the size of the rich core in the first metal. For example, experimental evidence indicates the relatively constant thickness of the shell containing the second metal in a range of particle sizes. Thus, as the particle size increases, the fraction (atom and / or weight) of the particle supplied by the core rich in the first metal generally increases, while the fraction of particles supplied by the shell containing the second metal generally decreases. However, the surface area of the second exposed metal increases with increasing particle size. For example, compared to a particle including a core 1 nm in diameter, in the constant thickness of the second metal shell, a particle including a core 10 nm in diameter, can provide up to a 100-fold increase in the surface area of the shell containing the second exposed metal.

A mechanism for deactivating conventional noble metal in carbon catalysts prepared by the deposition of noble metal, in the absence of a sacrificial metal involves the superoxidation of platinum as a result of the accumulation of charge between the active sites comprising the particles of atoms of the noble metal clusters . It is currently believed that particles containing the metal in which a shell containing a second metal at least partially surrounds a core containing the first metal results in the reduction of superoxidation of the catalyst. In this way, the shape of the catalyst provides an improvement in activity. With respect to a catalyst precursor structure, it is currently believed that the preferred deposition of the second metal by displacing the first metal to form active domains or sites less susceptible to agglomeration to form particles containing metal rather than the metal deposited in the absence of a sacrificial metal provides greater dispersion of the charge between the active sites and therefore the deactivation of the catalyst is reduced by the superoxidation of the metal.

It should be noted that a certain degree of agglomeration of the second metal to form particles containing basically the second metal can occur in catalysts containing the first and the second metal prepared in accordance with the present invention. However, it is currently believed that any agglomeration occurs to a lesser extent than those observed in catalysts prepared without a first sacrifice metal and, in any case, it is believed that the agglomeration of the second metal does not occur to any significant degree that would prevent realization of the benefits observed above the improved use of the metal.

It is also currently believed that the methods described above, using a first layer of sacrificial metal can be used in conjunction with the methods for treating porous substrates detailed elsewhere in this document. For example, a first metal can be deposited on a first porous support treated according to the methods described in this document (for example, a substrate having a pore blocking compound disposed and / or preferably kept within its micropores), followed by deposition from a second metal to one or more regions of the first deposited metal. Thus, it is currently believed that the deposition of both one and more than one region of the first metal, and later deposition of the second metal on them, is preferably directed towards the outside of the relatively small pore domain (for example, micropore) of the substrate, thus providing advantageous dispersion of the first and second metals and contributing to one or more of the benefits noted above with respect to the use of the metal.

A. First Metal

In these embodiments of the present invention where the catalyst or precursor includes one or more regions of a first metal on the support surface, the first metal is generally selected from the group consisting of vanadium, tungsten, molybdenum, gold, osmium, iridium, tantalum, palladium , ruthenium, antimony, bismuth, arsenic, mercury, silver, copper, titanium, tin, lead, germanium, zirconium, cerium, nickel, cobalt, iron, chromium, zinc, manganese, aluminum, beryllium, magnesium, lithium, cesium, barium and combinations thereof. In various preferred embodiments, the first metal is selected from the group consisting of copper, iron, tin, nickel, cobalt and combinations thereof. In several other preferred embodiments, the first metal comprises copper, tin, nickel or a combination thereof. In several other preferred embodiments, the first metal is tin or the first metal is copper. Still in additional modalities, the first metal comprises cobalt, copper, iron and combinations thereof. In several preferred embodiments, the first metal is copper. In several other preferred embodiments, the first metal is iron. In even more preferred embodiments, the first metal is cobalt.

Generally, the support is contacted with a deposition bath comprising ions of the first metal and one or more other components for depositing the first metal on the surface of the support. At least two events occur during the deposition of the first metal on the surface of the support: (1) nucleation (that is, the deposition of atoms of the first metal on the surface of the support) and (2) particle growth (that is, the agglomeration of atoms of the first deposited metal). As used herein, the term region (s) of the first metal refers to a group of atoms of the first metal agglomerated on the surface of the support. It is currently believed that the sizes, or dimensions of these regions (that is, the proportion of surface support area on which a region of the first metal is deposited), can directly impact the effectiveness / suitability of the catalyst.

For example, the deposition ratio, or deposition exchange sites of the second metal, decreases along with the decrease in the size of the region of the first metal. In addition, resistance to leaching and / or deactivation under reaction conditions generally decreases as one or more dimensions of the size of the region of the first metal decrease. Thus, it is preferable that the dimensions of the regions of the first metal are sufficiently resistant to leaching of the metals and provide a sufficient proportion of sites for the deposition of the second metal. Thus, one or more conditions of deposition of the first metal are preferably controlled to provide an appropriate balance between nucleation and agglomeration (i.e., particle growth) and thereby supply the regions of the first metal before suitable dimensions that provide sufficient exchange sites for depositing the second metal, are stable on their own and, thus, promote the deposition of stable domains, or regions of the second metal. For example, as detailed elsewhere, supports containing the first and second metal preferably include an excess of the first metal, which contributes to providing the second metal in a way that promotes the most efficient use of metals.

In addition to achieving a desirable balance between nucleation and agglomeration, the site, or dispersion of one or more regions of the first metal on the support surface can impact the use of the metal. That is, the considerations noted above generally in relation to the deposition of metal between relatively small pores generally apply equally to the deposition of one or more regions of the first metal and it is currently considered that the dispersion of these regions, between the pores of the substrate porous, affects the performance of the catalyst. Thus, one or more deposition conditions of the first metal are generally controlled and / or selected to provide a desired dispersion of the regions of the first metal. Thus, in general, the conditions for depositing the first metal preferably promote the deposition of the first metal on the support surface to provide regions of the first metal on the support having one or more dimensions that provide an adequate ratio of exchange sites to the deposition of the second metal on the surface of the regions of the first metal. More particularly, it is currently believed that the dimensions of the regions of the first metal preferably provide an adequate excess of the first deposited metal with respect to the desired proportion of the second metal to be deposited. For example, as detailed elsewhere, supports having first and second metals deposited thereon, according to the present invention, can be characterized by a minimum atom ratio of the first metal to the second metal.

1. Coordination Agents / Pore Blockers

In various preferred embodiments, the preferred deposition of the first metal outside the relatively small pores (e.g., the micropore domain) of the substrate can be promoted by the presence of one or more components of the first metal deposition bath. More particularly, the dispersion of first metal in this way can be promoted by the presence of one or more components of the deposition bath referred to herein as coordinating agent (s).

It is currently believed that a component of the first metal deposition bath can function as a coordinating agent, by forming one or more coordination bonds with the first metal and that the coordination compound thus formed may be unable to enter certain relatively small pores of the substrate, thereby preventing the first coordinated metal from settling between portions of the substrate surface. It should be understood that the exact form of any coordination link (s) between the compound and the metal, or the exact form of coordination of any compound formed in this way is not strictly critical. However, it is currently believed that a coordinating compound generally includes an association or bond between the first metal ion and one or more binding sites of one or more ligands. The coordination number of a metal ion of a coordination compound generally corresponds to the number of other bonding atoms attached to it. The ligands can be attached to the central metal ion by one or more coordinated covalent bonds, where the electrons involved in the covalent bonds are supplied by the ligands (that is, the central metal ion can be considered as an electron receptor, and the ligand can be considered as an electron donor). Typical donor atoms for binders include, for example, oxygen, nitrogen, and sulfur. The linkers can provide one or more potential binding sites; the ligands that offer two, three, four, etc., potential binding sites are called bidentate, tridentate, tetradentate, etc., respectively. Just as a central atom can coordinate with more than one linker, a linker with multiple donor atoms can link with more than one central atom. Coordination compounds including a metal ion attached to two or more binding sites of a particular linker are commonly referred to as chelates.

Additionally or alternatively, a coordinating agent as described herein can promote the dispersion of the first metal, on the support surface due to the coordination links between the coordinating agent and the metal to be deposited, to delay or delay the reduction of metal ions and the deposition of metal on the surface of the support, while promoting the dispersion of the first metal on the surface of the support. The coordination resistance between the coordinating agent and the metal, in general, influences the effectiveness of the agent in promoting the dispersion of the first metal on the support surface. Unless the coordination resistance reaches a minimum threshold, the effect of the agent on the dispersion will not be noticeable to any significant degree and the degree of coordination that prevails in the deposition bath will be essentially mimetic water solvation. As the co-ordination resistance between the agent and the metal increases, a higher concentration of reducing agent can be used and / or a relatively strong reducing agent (eg metal hydride) can be included in the deposition bath for promote the reduction of the coordination complex and / or reduction of the first metal and deposition. The Coordinating Agent and / or binder (s) derived from it present in the deposition bath can effectively function as a pore blocking compound during and / or after the deposition of the first metal. For example, once the coordination link (s) between the first metal and the coordinating agent is broken, the agent or binder (s) can be disposed within the micropores of the support.

According to the foregoing, with respect to the components of the deposition bath which can function as coordinating agents, in these and several other preferred embodiments, such components of the first metal deposition bath can promote the desirable dispersion of one or more regions of the first metal due to a pore blocking function. That is, in addition to preventing the entry of the first coordinated metal into certain pores of the substrate, the components of the first metal deposition bath described as coordinating agents can themselves be deposited between certain relatively small pores of the porous substrate, thereby inhibiting and preferably, substantially preventing the deposition of the first metal within the relatively small pores. In general, it is believed that these compounds function as pore blocking compounds during the deposition of the first metal and that the preferential deposition of the first metal and the pore blocking can occur substantially simultaneously, to provide a first metal impregnated substrate.

However, it should be understood that the treatment of a porous substrate according to the methods detailed above to dispose of and / or introduce a pore blocking compound in the pores of the substrate, following the deposition of metal, also provides suitable substrates.

A variety of compounds that function as coordination agents and / or pore blocking compounds can be included in the first metal deposition bath to provide one or more of the effects mentioned above. In general, these compounds are selected from the group consisting of various sugars, compounds containing 5 - or 6 ring members (eg, disubstituted 1,3- and 1,4-cyclohexanes), polyols, rochelle salts , acids, amines, citrates and combinations thereof. For example, the compound can be selected from the group consisting of sucrose, sorbitol, mannitol, xylitol, rochelle salts (sodium and potassium tartrate), ethylene diaminetetraacetic acid (EDTA), nhydroxyethylethylenediaminetetraacetic acid (HEDTA), nitrilotriacetic acid (NTA ), N, Ν, Ν ', Ν'-tetrakis (2-hydroxypropyl) ethylenediamine, and combinations thereof.

It should be noted that the advantageous effects provided by the presence of these compounds referred to herein as coordination agents or pore blockers are based, in part, on experimental evidence. Although it is currently believed that one or more of these compounds provide either or both of the pore blocking and coordination functions, it should be understood that the present invention is not dependent on either or both theories and does not require one or more compounds that provide either or both of these functions.

In various preferred embodiments (for example, those in which the first metal is copper or iron), the deposition bath comprises sucrose which is believed to function as a coordinating agent and / or pore blocking compound. In addition to these effects, according to the previous discussion, your presence can offer other advantages. For example, as detailed here elsewhere, the first metal deposition can proceed more quickly at a higher pH. The sucrose coordination effect allows the deposition of the first metal at a higher pH, since the coordination effect reduces the risk of excessive precipitation of the first metal at a higher pH.

Generally, the coordinating agent / pore blocker, or a combination of agents / blockers, is present in the first metal deposition bath at a concentration of at least about 10 g / l, at least about 20 g / l, or at least about 30 g / L. Preferably, this component of the first metal deposition bath is present in a concentration of about 10 g / l to about 115 g / l, about 25 g / l to about 100 g / l, or about 40 g / about 85 g / l. In addition, according to these and several other preferred embodiments, the weight ratio of coordinating agent to the first metal in the deposition bath is generally at least about 3: 1, typically at least about 5: 1 and, more typically, at least about 8: 1. For example, generally the weight ratio of coordinating agent to the first metal in the deposition bath is generally about 3: 1 to about 20: 1, typically between about 5: 1 to about 15: 1 and, more typically, between about 8: 1 and about 12: 1.

2. Autocatalytic plating of the First Metal

Generally and in accordance with the foregoing, the deposition of the first metal on the surface of the support can be conducted according to conventional methods known in the art. Thus, typically, the deposition of the first metal is conducted by autocatalytic plating, in which the support is brought into contact with a deposition bath generally comprising a source of the first metal in the absence of an externally applied stress. The deposition bath generally comprises a reducing agent that reduces the ions of the first metal to form metal atoms that are deposited on the surface of the support.

Generally, the origin of the first metal is a first metal salt, including, for example, sulfates of the first metal, nitrates of the first metal, chlorides of the first metal, tartrates of the first metal, phosphates of the first metal and combinations thereof. The concentration of the first metal in the deposition bath is generally selected in view of the content of the first desired metal. Typically, the source of the first metal is present in the deposition bath at a concentration of at least about 0.25 g / L, at least about 1 g / L, at least about 2.5 g / L, or at least least about 4 g / L. For example, the source of the first metal may be present in the deposition bath at a concentration of about 1 to about 20 g / L, about 2.5 to about 12.5 g / L, or about 4 to about 10 g / L.

3. Copper deposition

The discussion that follows focuses on the deposition of copper as the first metal on a porous carbon support. However, as detailed elsewhere here, it is to be understood that the present invention also contemplates the deposition of first metals other than copper on carbon supports, and the deposition of copper and other first metals on different carbon supports.

(A) Copper Sources

Sources of copper ions suitable for use in the methods of the present invention include copper salts, such as nitrate, sulfate, chloride, acetate, oxalate and format and copper salts and combinations thereof. Salts containing copper in the bivalent state (i.e., Cu (II)) are generally preferred, including, for example, copper sulfate.

(B) Loading Copper in the Deposit Bath

The loading of the first metal into the deposition bath can affect the quality (e.g., resistance to leaching) and / or suitability (e.g., the dispersion of the first metal over a sufficient portion of the support surface) of the deposition of the first metal. More particularly, it is currently believed that the relative proportions of the first metal and the support impact the deposition of the first metal. The agglomeration, or particle growth, and the dimensions of the regions resulting from the first metal may increase with increasing copper load. As noted above, the dimensions of the regions of the first metal are preferably controlled to promote an appropriate balance between dispersion and stability of the first and the second metal. Thus, the copper concentration in the deposition bath meets the limits observed above and / or is within the values observed above.

For example, copper is generally present in the first metal deposition bath at a concentration of at least about 0.25 g / L, more generally, at least about 1 g / L, still more generally, at least about 2 g / L, and even more typically at least about 3 g / L (e.g., at least about 5 g / L). Preferably, copper is present in the first metal deposition bath at a concentration of about 0.25 to about 15 g / L, more preferably about 1 to 12 g / L and, most preferably, about 2 to about 10 g / L.

(C) Reducing Agents

Suitable reducing agents include those generally known in the art, including, for example, sodium hypophosphite (NaH ₂ PO ₂ ), formaldehyde (CH ₂ O) and other aldehydes, formic acid (HCOOH), formic acid salts, salts of borohydride (eg sodium borohydride (NaBH ₄ )), substituted borohydride salts (eg sodium triacetoxyborohydride (Na (CH ₃ CO ₂ ) ₃ BH)), sodium alkoxides, H ₂ NNH ₂ (hydrazine) and ethylene glycol. In several preferred embodiments, formaldehyde is the preferred reducing agent. For copper deposition in non-aqueous deposition baths, hydrogen gas is often the preferred reducing agent, as it is usually easily soluble in organic solvents.

The way of adding the reducing agent to the deposition bath is not strictly critical, but in several embodiments the reducing agent is added at a relatively slow rate (for example, over a period of about 5 minutes to 3 hours, or over a period of about 15 minutes to about 1 hour) for a slurry of the support and first metal in water or an alcohol and under an inert atmosphere (for example, N ₂ ). If the reducing agent is firstly added to the copper salt, preferably it can be added to a solution containing the copper salt and also a coordinating agent (for example, a chelator). The presence of the chelator inhibits the reduction of copper ions before the copper salt solution is combined with the support and which, as detailed in this document, can likewise promote the beneficial deposition of the first metal on the entire surface of the support.

Typically, in the case of formaldehyde as a reducing agent, the reducing agent is present in the first metal deposition bath at a concentration of at least about 1 g / L, more typically at least about 2 g / L and even more typically at least about 5 g / L. For example, in the case of formaldehyde as a reducing agent, formaldehyde is preferably present in the deposition bath at a concentration of about 1 to about 20 g / L, more preferably about 2 to about 15 g / L and, even more preferably, from about 5 to about 10 g / L.

In addition or alternatively, in the case of a formaldehyde reducing agent, formaldehyde and, in general, the first metal (eg copper) are present in the deposition bath in a weight ratio of formaldehyde to the first metal of at least about 0.5: 1 and typically at least about 1: 1. For example, in various embodiments, the weight ratio of formaldehyde to the first metal in the deposition bath is about 0.5: 1 to about 5: 1, from about 1: 1 to about 3: 1, or from about 1: 1 to about 2: 1.

(D) Temperature

The temperature of the deposition bath can affect the nucleation and agglomeration (for example, the growth of particles) that occur during the deposition of the first metal. For example, nucleation (that is, metal deposition) and agglomeration, in general, increase with increasing temperature of the deposition bath.

Thus, preferably the temperature of the deposition bath does not reach a level that promotes metal agglomeration and / or metal leaching under reaction conditions to an undesirable degree. Reducing the temperature of the plating bath generally suppresses nucleation to a greater degree of agglomeration. Thus, the temperature of the plating bath is preferably high enough that the nucleation is not delayed to an unacceptable degree. According to the present invention, it is currently believed that the first metal deposition baths with a temperature of about 5 ° C to about 60 ° C in general, answer these concerns and provide adequate deposition of the first metal. Preferably, the temperature of the first metal deposition bath is about 10 ° C to about 50 ° C, more preferably, the temperature of the first metal deposition bath is about 20 ° C to about 45 ° C . It should be noted that the reference to the temperature of the first metal deposition bath can refer to the temperature of the bath before and / or during contact of the deposition bath and the support.

(E) Agitation

Preferably, the first metal deposition bath is agitated to promote dispersion of the first metal on the surface of the support. Agitation can also promote the diffusion of the reducing agent throughout the support. Experimental evidence indicates that sufficient agitation can contribute to the improvement of catalytic activity. However, excessive agitation of the deposition bath can cause copper dispersion to a degree that provides regions of first metal that may be less resistant to leaching than less dispersed regions. For example, the undesirably high dispersion may result in the deposition of a portion of the first metal within relatively small pores of the support that is less prone to agglomeration to form regions of the first metal, which are generally resistant to leaching.

In addition, it is currently believed that the type of agitator can affect the deposition of the first metal. Experimental evidence indicates that the first metal (copper), can be deposited on the surface of the agitator resulting in reduced deposition of the first metal to the carbon support and, therefore, reduced sites for deposition of the second metal. For example, the first metal can settle on the surface of stirrers that include or are made of metal (for example, coated metal stirrers). Thus, in several preferred embodiments, the agitator consists of materials that generally prevent and, preferably, completely substantially prevent the deposition of the first metal on the surface of the agitator. For example, the stirrer may be constructed, preferably, of glass or of various other materials which, preferably, prevent the deposition of the first metal on the surface of the stirrer.

(F) Deposition pH

Copper deposition is generally more effective at a higher pH (for example, greater than about 8, greater than about 9 or greater than about 10). In fact, as the pH of the deposition bath increases, the deposition of copper through reduction and precipitation on the support can proceed at a rate that can make it difficult to sufficiently disperse the first metal on the support surface. In addition to the benefits mentioned above, it is currently believed that the presence of a coordinating agent such as sucrose slows down the precipitation of copper at a high pH and thus promotes sufficient dispersion of the metal on the surface of the support. Formation of a coordination complex between the first metal and a coordinating agent is usually enhanced at the pH levels noted above. However, at certain levels of the pH of the deposition bath it can negatively impact the process of solvation of the ions of the first metal and the deposition and reduction of the first metal. Thus, in various preferred embodiments in which a coordinating agent is present in the deposition bath, the pH of the deposition bath is about 8 to about 13, or about 9 to about 12.

4. Iron deposition

In several preferred embodiments, the first metal is iron. Generally, the deposition of iron on the surface of the support can be conducted according to conventional methods known in the art (for example, autocatalytic plating). Thus, the deposition of iron is normally conducted by a process that comprises contacting the support with a deposition bath comprising a source of the first metal, in the absence of an externally applied tension. For example, iron can be deposited through autocatalytic deposition, in general, using methods known in the art, including, for example, those described in U.S. Patent No. 6,417,133 and by Wan et al. in international publication No. WO 2006/031938. In several modalities, as detailed below, the deposition bath comprises a reducing agent, which reduces the ions of the first metal that are deposited on the surface of the support.

(A) Iron Sources

Appropriate sources of iron include iron salts, such as nitrate, sulfate, chloride, acetate, oxalate and format salts, and combinations thereof. In several preferred embodiments, the iron source comprises iron chloride (i.e., FeCb), iron sulfate (i.e., Fe ₂ (SO ₄ ) 3), or a combination thereof.

The concentration of the iron source in the deposition bath is not strictly critical and is generally selected in view of the desired metal content and / or the composition of the source. Often, the iron source is present in the deposition bath at a concentration of at least about 5 g / L and more typically from about 5 to about 20 g / L. In various embodiments, the total proportion of the iron source is introduced into the deposition bath before, during or after the addition of the carbon support to the deposition bath and / or to the vessel with the deposition bath. Additionally or alternatively, (including, as described in the working examples), the iron source can be measured, or pumped into the deposition bath and / or a vessel containing the carbon support. In this regard, it is necessary to understand that in addition the metered addition of iron source is controlled to provide the deposition of an adequate proportion of iron on the support surface, regardless of the concentration of iron source in the deposition bath at any point (s) during iron deposition.

(B) Loading Iron in the Deposit Bath

As with other first metals (e.g. copper, as described above), the iron load in the deposition bath can affect the quality and / or dispersion of iron deposition over a sufficient portion of the support surface. The concentration of iron in the deposition bath is generally controlled to address these concerns and others (for example, the agglomeration of the first metal). For example, iron is normally present in the first metal deposition bath at a concentration of at least about 2 g / L, more typically, at least about 3 g / L and, even more typically, at least about 4 g / L. Preferably, the iron is present in the deposition bath at a concentration of about 2 to about 8 g / L, more preferably about 3 and 6 g / L and, most preferably, about 4 to about 5 g / L.

(C) Reducing Agents

In order to provide a driving force for the deposition of a second metal on it, iron is preferably deposited in an at least partially reduced state, for example, as Fe ²⁺ and / or its totally reduced state as Fe °. Thus, in various embodiments, the first iron metal deposition bath comprises a reducing agent. Any reducing agent is generally used under the conditions set out above with respect to copper deposition (eg, reducing agent concentration, etc.). Suitable reducing agents include sodium hypophosphite (NaH ₂ PO ₂ ), formaldehyde (CH ₂ O), formic acid (HCOOH), formic acid salts, sodium borohydride (NaBH ₄ ), sodium triacetoxyborohydride (Na (CH ₃ CO ₂ ) 3BH)), sodium alkoxides, hydrazine (H ₂ NNH ₂ ) and ethylene glycol. In view of the greater electropositivity of iron compared to copper, stronger reducing agents for the first deposition of iron metal may be preferred over those preferred for the first deposition of copper metal. Thus, in several preferred embodiments, the reducing agent is sodium borohydride or ethylene glycol.

In these embodiments where the reducing agent is sodium borohydride and / or ethylene glycol, the molar ratio of the deposited iron reducing agent is generally at least 1, usually at least about 2, and more generally at least about 3. Usually , in accordance with these modalities, the molar ratio of sodium borohydride to the deposited iron is from about 1 to about 5 and, more generally, from 2 to about 4.

(D) Temperature

As with copper deposition, the temperature of the deposition bath affects iron nucleation and agglomeration. Generally, the temperature of the deposition bath is sufficient to provide adequate nucleation and agglomeration, but preferably not at a level that promotes the first metal agglomeration to an undesired level. Generally, iron deposition bath temperatures ranging from about 5 ° C to 60 ° C can be used to provide suitable catalysts. The temperature of the iron deposition bath is often above ambient conditions in order to provide sufficient nucleation and, more particularly, the proper dispersion of the first metal on the support surface. Thus, normally the temperature of the iron deposition bath is from about 25 ° C to about 60 ° C and, more generally, from about 25 ° C to about 45 ° C.

(E) Agitation

The first metal-to-iron deposition bath is usually agitated to promote dispersion of iron over the surface of the support. As in copper depositions, agitation can also promote the diffusion of the reducing agent throughout the support. Any agitation during the deposition of the first metal is generally carried out according to the above description in relation to copper deposition.

(F) Deposition pH

As with copper deposition, iron deposition generally proceeds more easily with increasing deposition pH. Thus, normally the pH of iron deposition is at least about 8, at least about 9, or at least about 10. Also as with iron deposition, it is currently believed that the presence of a coordinating agent (eg sucrose) slows down the precipitation of iron at a high pH and thus promotes sufficient dispersion of the metal on the surface of the support. As noted, the formation of a coordination complex between the first metal and a coordinating agent is generally enhanced at the above-mentioned pH levels. But at certain pH levels, the pH of the deposition bath can negatively impact solvation or iron ions and the reduction and deposition of the first metal. Thus, in several preferred embodiments, the pH of the iron deposition bath is about 8 to about 13, or about 9 to about 12.

5. First Metal Deposition Atmosphere

Regardless of the precise conditions for the deposition of the first metal and the dispersion of the first metal deposited on the surface of the support, oxidation of the first deposited metal can reduce the proportion of exchange sites for the first metal available for the second metal deposition. Thus, in various preferred embodiments, the first metal is deposited on the support, in the presence of a non-oxidizing environment (for example, a nitrogen atmosphere). Additionally or alternatively, water and / or other deposition bath components are degassed to remove dissolved oxygen using methods known to those skilled in the art.

B, Second Metal

Conventional noble metal catalysts are generally prepared by depositing a noble metal on the surface of a support, usually a porous carbon support. The agglomeration of particles in noble metals, thus reducing the exposed catalytic surface area of the metals, has been observed with these methods. In particular, an abundance of particles containing relatively large metals may represent the inefficient use of the metal because these particles provide a relatively low exposed catalytic surface area per unit of the metal.

According to various embodiments of the present invention, catalysts containing noble metals are prepared by a method in which the noble metal is deposited in a way that increases the catalytic surface area of the metal exposed per unit weight of the metal. More particularly, the noble metal is deposited on the surface of one or more regions of the first metal by displacing the first metal from the regions. It is currently believed that the deposition of the noble metal, using a first sacrifice metal, results in reduced noble metal agglomeration. For example, as noted elsewhere here, deposition of the noble metal in this way provides a catalyst precursor structure in which the noble metal deposited on the surface of one or more regions of a first metal is less prone to agglomeration than noble metals deposited directly on the surface of a porous support. It is currently believed that, after the heat treatment of supports having noble metal deposited in them in this way, the metal particles are formed in such a way as to provide improved use of the noble metal (second) (for example, a catalytic surface area of the metal exposed per unit weight of metal).

Generally, the second metal is deposited on a first metal-impregnated support by contacting the metal-impregnated support and a second metal deposition bath. More particularly, the second metal is generally deposited by autocatalytic deposition in which the first metal impregnated support and the second metal deposition bath are contacted in the absence of an externally applied tension.

As noted, in several modalities, the second metal is a noble metal. Typically, the noble metal is selected from the group consisting of platinum, palladium, ruthenium, rhodium, iridium, silver, osmium, gold, and combinations thereof. In various preferred embodiments, the noble metal comprises platinum. In still other preferred embodiments, the noble metal comprises more than one metal (for example, platinum and palladium or platinum and gold).

The discussion that follows focuses on the deposition of platinum as the second metal, but it must be understood that the present invention also contemplates the use of any or all of the noble metals mentioned above as the second metal. In addition, the suitability of a combination of metals for use in displacement deposition of a second metal in one or more regions of a first metal, in general, depends on their relative electropositivity. Thus, the present invention is not limited to the deposition of noble metals such as the second metal. For example, two metals designated as candidates for first metals elsewhere in this document may supply the first and second metals, as long as their relative electropositivity allows displacement deposition of the second metal in one or more regions of the first metal.

Suitable sources of platinum include those generally known in the art for use in liquid platinum deposition and include, for example, H ₂ PtCI ₄ , H ₂ PtCI ₆ , K ₂ PtCI ₄ , Na ₂ PtCI ₆ and combinations thereof. Thus, in various preferred embodiments, the second metal deposition bath comprises a source of platinum, including a platinum salt comprising platinum in an oxidation state of +2 and / or +4. As noted, in several preferred embodiments the source of platinum provides platinum ions exhibiting a +2 oxidation state. However, it must be understood that effective catalysts can be prepared using platinum sources that provide platinum ions with other oxidation states (eg +4), and platinum sources that provide platinum ions that comprise ions platinum exhibiting oxidation states other than +2. Likewise, noble metal sources other than platinum and second metal sources, in general, which provide metal ions in lower oxidation states are also preferred. For example, it is currently believed that the palladium supplied by Na ₂ PdCl4 and PdCI ₂ can be used to prepare an active catalyst comprising palladium as the second metal.

Generally, the platinum source is present in the second metal deposition bath in a proportion that provides a lower molar concentration of ions of the second metal than the ion concentration of the first metal in the first deposition metal bath. Typically, the molar ratio of copper ions in the first metal bath to noble metal ions in the second metal deposition bath is greater than 1, more typically and at least about 2, and even more typically, at least about 3 ( for example, at least about 5). In various preferred embodiments, the molar ratio of copper ions in the first metal deposition bath to that of noble metal ions in the second noble metal deposition bath is generally greater than 1 to about 20, more typically about 2 to about 15, even more typically about 3 to about 10, and more generally, from about 5 to about 7.5.

Generally, the first metal impregnated support is not subjected to high temperatures prior to contact with the second metal deposition bath. That is, the structure of the catalyst precursor is preferably not subjected to temperatures that promote the formation of particles containing metal (for example, by agglomerating particles of the first metal). For example, the support impregnated with the first and the second metal is generally subjected to temperatures not exceeding about 200 ° C, no more than about 150 ° C and, preferably, no more than about 120 ° C before the contact with the second metal deposition bath.

Usually, the metal impregnated support and the second metal deposition bath are contacted with a temperature of at least about 5 ° C, usually at least about 10 ° C and, more generally at least about 15 ° C. Preferably, the first metal impregnated support and the second metal deposition bath are contacted, at a temperature of about 10 ° C to about 60 ° C, from about 20 ° C to about 50 ° C, or from about 25 ° C to about 45 ° C.

Often, the second metal deposition bath has a pH lower than the pH of the first metal deposition bath and is about 1 to 12 or from about 1.5 to about 10. According to the In various embodiments, the pH of the deposition bath is about 2 to about 7 or about 3 to about 5. Such pH conditions have been found to be suitable for the deposition of a noble metal (second) in one or more regions of the first copper metal. In several preferred embodiments, the first metal is iron. In comparison with copper, iron can be more easily leached from the support surface as the pH of the deposition bath decreases. Thus, according to the modalities in which the first metal is iron, the pH of the noble metal deposition bath (second) is usually about 4 to about 9, and preferably about 5 to about 8 (for example, about 7).

As noted above, preferably the first metal is deposited in an environment that prevents oxidation of the first deposited metal which can reduce the proportion of exchange sites for the first metal available for deposition of the second metal. Likewise, in various preferred embodiments, the second metal is also deposited on the substrate impregnated with the first metal in a non-oxidizing environment (for example, a nitrogen atmosphere) to prevent oxidation of the first and second deposited metals.

C. Support Impregnated with the First and Second Metal

As noted, preferably, the first metal deposited on the support surface offers suitable exchange sites for the deposition of the second metal on the surface of one or more regions of the first metal and, more particularly, an excess of exchange sites for the deposition of the second metal. Thus, normally the ratio of atoms of the first metal to the second support metal impregnated with the first and the second metal (i.e., the structure of the catalyst precursor) is at least about 1.5, more generally at least about 2, and even more generally at least about 3 (for example, at least about 4 or at least about 5). Preferably, the ratio of atoms of the first metal to the second support metal impregnated with the first and the second metal is from about 1.5 to about 15, more preferably from about 2 to about 15, even more preferably from about 3 to about 10, and even more preferably about 4 to about 8.

As noted, the heat treatment of the impregnated support provides particles of the containing the first metal and the noble metal (second) on the surface of the support, including the noble metal (second) in a form that allows the advantageous use of the metal. An excess of atoms of the first metal to atoms of the second metal on the impregnated support is believed to result in the formation of such particles. For example, the excess of atoms from the first metal to the second metal in the impregnated support provides rich particles of first metal that include a relatively low proportion of unexposed noble metal (second) throughout the particles (for example, a bimetallic alloy having a excess of atoms of the first metal).

Additionally or alternatively, and as generally shown in Figure 2, the heat treatment of the support impregnated with the first and the second metal can form metal particles comprising a core and a shell, at least partially surrounding the core. It is currently believed that the composition of the core and shell indicates improvements in the use of metals and, more particularly, improvements in the use of the second metal (for example, noble metal). For example, the core of these particles is generally rich in the first metal, thus providing a relatively low proportion of the second unexposed metal throughout the particles.

As the ratio of atoms of the first metal to the second metal increases from catalyst precursor, as the first metal-rich core, the extent to which the core rich in the first metal is surrounded by the shell containing the second metal may decrease. For example, a relatively high excess of exchange sites for the first metal for deposition of the second metal can result in a portion of exchange sites that do not participate in the deposition by displacement of the noble metal (second). Such particles can be prepared from catalyst precursors where the atom ratio is close to or above the upper limit observed above the atom ratios of the first metal to the second metal (for example, about 10 or higher). Although less preferred, it should be understood that a decrease in the degree to which the core is surrounded by a shell containing the second metal does not necessarily indicate a lack of use of the improved second metal. These particles can still provide use of the improved metal based, for example, on a core rich in the first metal that provides a relatively low proportion of potentially unused, unexposed, noble metal (second). However, it is currently believed that the particle structure can move towards an increased coverage of the core rich in the first metal by the shell containing the second metal. More particularly, this deviation in the form of particles may comprise the leaching of the first metal from metal particles on the support surface during the use of the catalyst in liquid phase reactions. The second metal can likewise be removed or leached from the particles, but it is currently believed that the first metal is removed from the particles to a greater degree than the second metal. Thus, the most preferred approaches to the ratio of atoms of the first metal to the second metal vary and it is currently believed that, as a result of this removal, the particle structure deviates towards a more preferred (ie more extensive) coverage of the nucleus rich in the first metal by the shell containing the second metals. After a period of use, leaching of the first metal from metal particles on the surface of the support generally decreases. After that period of use, it is currently believed that catalysts comprising particles having a more preferred ratio of atoms of the first metal to atoms of the second metal with satisfactory deviation in structure, then exhibit performance characteristics comparable to catalysts prepared using the ratios more preferred from atoms of the first metal to atoms of the second metal. This self-correction of behavior was observed, for example, in connection with catalysts in which the first metal is copper and the second metal is platinum.

D. Heat treatment of substrates impregnated with Primer and Primer

Second metal

As noted, it should be understood that the metal impregnated support of the present invention is a suitable catalyst as described in the working examples detailed here. However, typically, according to various preferred embodiments, the metal impregnated support is treated at elevated temperatures, generally, as detailed here elsewhere (for example, in the presence of a non-oxidizing environment at temperatures above about 800 ° C) to form a finished catalyst. Typically, the metal impregnated support is heated to temperatures from about 400 ° C to about 1000 ° C, more typically from about 500 ° C to about 950 ° C, even more typically from about 600 ° C to about 950 ° C and, even more typically, between about 700 ° C to about 900 ° C. Submitting metal-impregnated supports to such temperatures provides finished catalysts that exhibit reduced metal leaching and better utilization of the metal, as detailed here elsewhere (for example, catalysts that comprise particles rich in the first metal and / or particles including a core rich in the first metal at least partially surrounded by a shell rich in the second metal).

It is currently believed that particles of stable metals (that is, resistant to leaching) are easily formed in the case of substrates impregnated with the first and the second metal, where the first metal is iron and the second metal is platinum. Supports impregnated with iron and platinum (ie precursors of iron-platinum catalyst) were observed to exhibit adequate stability during the reaction test. Preferably, however, the ferro-platinum catalyst precursor is subjected to elevated temperatures to prepare a finished catalyst. It is currently believed that heating the substrate impregnated with iron-platinum improves activity. However, in view of the good stability of supports impregnated with iron and platinum, suitable catalysts can be prepared therefrom by heating the catalyst precursor to temperatures within, but at or near the lower limits of the intervals noted above. Thus, according to certain modalities, supports impregnated with iron and platinum are subjected to a maximum temperature of about 400 ° C to about 750 ° C, or from about 500 ° C to about 650 ° C for prepare a finished catalyst.

As noted, the degree of alloy of the first and the second metal generally increases with increasing temperature to which the metal impregnated support is subjected. Thus, it is currently believed that by submitting the iron / platinum impregnated support to a relatively low maximum temperature, a relatively low degree of iron alloy and platinum is provided. Although the catalysts of the present invention include the first and second metals in a form that represents efficient metal use (e.g., a metal-rich first alloy), the formation of an inevitably alloy results in unexposed noble metal (second). Thus, the preparation of catalysts containing platinum and iron, subjecting the support impregnated with metal at relatively low temperature can contribute to an improved use of metal. However, in this regard it should be noted that the preparation of platinum and iron catalysts, subjecting the supports to higher temperatures, for example, at observed intervals such as 700 ° C or higher, is also currently believed to provide catalysts that represent the more efficient use of metal.

E. Iron and Platinum Deposition Protocols

Suitable platinum and iron catalysts can generally be prepared according to the above discussion considering the deposition of iron (first metal) and platinum (second metal), both according to the above discussions regarding the first and the second metal in general and, specifically, iron and platinum. However, according to the present invention, it has been found that advantageous catalysts are provided by combinations of particular characteristics of iron (first metal) and platinum (second metal) deposition.

For example, in various preferred embodiments, the iron (first metal) deposition bath comprises ethylene glycol as a reducing agent, but does not comprise a separate coordinating agent (for example, sucrose). However, it should be understood that the ethylene glycol reducing agent can, in fact, function as a coordinating agent to some degree.

In still other preferred embodiments, the iron deposition bath comprises both a reducing agent and a coordinating agent. In various modalities of this type, ethylene glycol is the reducing agent and sucrose is the coordinating agent. In such additional embodiments, ethylene glycol and sodium borohydride are used as reducing agents for iron deposition, and the iron deposition bath also comprises sucrose as a coordinating agent.

In several other preferred embodiments, the iron deposition bath (metal first) comprises sodium borohydride as a reducing agent, generally, according to the above discussion. The iron deposition bath does not comprise a separate coordinating agent (for example, sucrose).

F. Catalysts Containing First and Second Metal

As noted, supports impregnated with the first and second (noble) metals typically contain an excess of atoms of the first metal over atoms of the second metal. According to these and several other embodiments, in general, the first metal constitutes at least about 1% by weight, at least about 1.5% by weight, or at least about 2% by weight of the catalyst . Typically, the first metal constitutes at least about 3% by weight, at least about 4% by weight, or at least about 5% by weight of the catalyst. For example, preferably, the first metal constitutes from about 3% to about 25% by weight of the catalyst, more preferably from about 4% to about 20% by weight of the catalyst and, even more preferably, from about 5% to about 15% by weight of the catalyst. In several other embodiments (for example, those in which iron is the first metal), the first metal constitutes from about 1% to about 10% by weight, more preferably from about 1.5% to about 8% by weight and, even more preferably, from about 2% to about 5% (e.g., about 4%) by weight of the catalyst.

According to the foregoing, catalysts of various embodiments of the present invention generally contain at least about 1% by weight of noble metal (second), at least about 2% by weight of a noble metal, or at least about 3% by weight of a noble metal. Typically, catalysts contain less than about 8% by weight of a noble metal, more typically less than about 7% by weight of a noble metal and, even more typically, less than about 6% by weight of a noble metal . According to various preferred embodiments, catalysts contain less than about 5% or less than about 4% by weight of a noble metal (for example, from about 1% to about 3% by weight of a noble metal) . Catalysts prepared as detailed herein use noble metal (second) more efficiently, compared to conventional catalysts, thereby providing catalysts at least as active or even more active than conventional noble metal containing catalysts. For example, catalysts can be prepared so that they include metal fillers similar to conventional noble metal containing catalysts, but are generally more active and, in various preferred embodiments, much more active than conventional noble metal containing catalysts. In this way, the catalytic activity can be increased without an increase in the noble metal charge, which may be undesirable due to processing limitations. In various embodiments, active catalysts can be prepared so that they contain from about 3% to about 6% by weight of a noble metal, or from about 4% to about 5% by weight of a noble metal.

As a further example, the use of more efficient metal by catalysts of the present invention allows the preparation of catalysts that include a reduced proportion of second metal, when compared to conventional catalysts containing noble metals, but which are at least as active and, in several preferred embodiments, more active than conventional catalysts containing noble metals. In this way, the catalysts of the present invention can provide activities equivalent to those provided through catalysts containing conventional noble metals in lower noble metal fillers, or larger catalytic activities in equivalent noble metal fillers. For example, in various embodiments, active catalysts can be prepared that contain from about 1% to about 5% by weight, from about 1.5% to about 4% by weight, or between about 2% to about 3% by weight of a noble metal.

In various embodiments, the ratio of atoms of the first metal to atoms of the second metal in metal particles on the surface of the catalyst support generally increases with increasing particle size. It is currently believed that as the particle size increases, the portion of the particles that make up the core rich in the first metal increases, while the portion (that is, the fraction by weight) of the particles that make up the shell containing the second metal decreases. As previously noted, particles containing larger metals are generally more resistant to leaching from the surface of the catalyst support. However, a significant fraction of larger particles is generally undesirable in catalysts containing conventional noble metals, as the particle size increases the proportion of noble metal distributed within the particles that do not contribute to the efficient catalytic surface area increases. Thus, a relatively high proportion of large particles, comprising a shell rich in the second metal according to the present invention provides improved stability without sacrificing the catalytic surface area of the exposed (second) metal associated with the relatively large particles in the catalysts. conventional metals containing noble metals.

For example, in various embodiments, the catalyst includes metal-containing particles characterized by a particle size, as determined using electron microscopy, so that a significant fraction (for example, at least about 80%, at least about 90%, or at least about 95%, numerical basis) of the particles is about 5 to about 60 nm, or about 5 to about 40 nm in its largest dimension. In addition, the thickness of the shells containing the second particle metal within these nm size distributions is typically less than about 3 nm, more typically less than about 2 nm, and preferably less than about 1 nm (for example, less than about 0.8 nm or less than about 0.6 nm).

Improvements in the use of metal can be characterized by an increase in the proportion of exposed noble metal (second) of the catalyst. More particularly, improvements in the use of metal can be indicated by an increase in the surface area of the exposed noble metal per unit weight of catalyst per unit weight of noble metal. The total exposed noble metal surface area of the catalysts of the present invention can be determined using static carbon monoxide chemisorption analysis, including a protocol described in example 67. The carbon monoxide chemisorption analysis described in example 67 includes first and second cycles. Catalysts of the present invention subjected to this analysis are generally characterized as chemovents of at least about 500 pmols of carbon monoxide per gram of catalyst per gram of noble metal and, more generally, at least about 600 pmols of carbon monoxide per gram. of catalyst per gram of noble metal. Typically, the catalysts of the present invention are characterized as chemovents of at least about 700, at least about 800, at least about 900, at least about 975, at least about 1000, or at least about 1100 pmols of carbon monoxide per gram of catalyst per gram of noble metal.

An additional or alternative indicator of efficient metal use is the proportion of noble metal (second) of the catalyst that can be found inside a shell, at least partially surrounding a core rich in the first metal. Generally, at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% noble metal is present inside the shell of the metal particles . Typically, at least about 60% and, more typically, at least about 70% (for example, at least about 80% or at least about 90%) of noble metal is present within the shell of the particles of metal.

Additionally or alternatively, the efficient use of metal can be indicated by the proportion of noble metal (second) on the surface of metal particles. That is, the efficient use of metal can be indicated by the proportion of noble metal on the surface of the particles rich in the first metal, for example, the second metal present in an alloy and / or inside a shell rich in the second metal, at least partially surrounding a rich core in the first metal. Generally, the percentage of noble metal atoms on the surface of the particles containing the first metal and the noble metal (second) is at least about 2%, or at least about 5%. Typically, the percentage of noble metal atoms on the surface of the particles containing the first metal and the noble metal, is at least about 10%, more typically at least about 20%, even more typically at least about 30% and, preferably at least about 40% (for example, at least about 50%).

The results of in-line scanning analysis by X-ray energy dispersive spectroscopy (EDX) for the catalysts of the present invention (for example, as described in protocol B in example 68) also indicate the efficient use of metal. More particularly, the results of in-line scan analysis for the metal particles of catalysts of the present invention indicate a noble metal distribution (second) in which a significant fraction of noble metal (second) is present within a shell, at least partially surrounding a rich core in the first metal. Additionally or alternatively, the results of the in-line scan analysis for metal particles of catalysts of the present invention indicate a noble metal distribution, in which a significant fraction of noble metal is disposed on or near the surface of a metal particle (s) .

The efficient use of metal in catalyst particles of the present invention is indicated by the distribution of a second metal that produces an EDX in-line scan signal that does not vary significantly over a scan region. As used herein, the term scanning region refers to the portion of the largest dimension of the analyzed particle over which a relatively low degree of variation in the second metal signal indicates improved metal utilization. A relatively constant in-line scan signal of the second metal over a scan region that corresponds to a significant part of the larger particle size indicates that a significant fraction of the second metal is distributed close to the particle's surface rather than along the entire metal particle. In contrast, the latter type of distribution would cause the second metal signal to increase (decrease) significantly in the portion of the scanning region, where the probe is directed to a thickness (thinner) dimension of the particle. For example, in several embodiments, the second metal signal generated during the EDX in-line scan analysis of a particle on the surface of a catalyst according to the present invention varies by no more than about 25%, no more than that about 20%, no more than about 15%, no more than about 10%, or no more than about 5% of over a scanning region that is at least about 70% of greater dimension of at least one particle, in additional modalities, the second metal sign varies by no more than about 20%, no more than about 15%, no more than about 10%, or no more than that about 5% of over the scan region through a region that is at least about 60% of the largest dimension of at least one particle. In yet other modalities, the signal of the second metal varies by no more than about 15%, no more than about 10%, or no more than about 5% over a scanning region that is at least about 50% of the largest dimension of at least one particle.

Particles having metal distributions characterized by EDX in-line scan analysis as detailed above are typically rich in the first metal and, more particularly, typically include the second metal and the first metal in an atomic ratio of the second metal to the first metal in a particle (s) analyzed of less than 1: 1. Typically, the atomic ratio of the second metal and the first metal of the particle (s) is less than about 0.8: 1 and, more typically, less than about 0.6: 1 (for example, less than about 0.5: 1).

In general, the particle (s) of the first and second metal of the catalysts of the present invention having a second metal distribution characterized by in-line scanning analysis of EDX indicating efficient use of metal have a larger dimension of at least less about 6 nm, typically at least about 8 nm, more typically at least about 10 nm, and even more typically at least about 12 nm.

The relative magnitudes of the first and second metal signals along the scan region can also indicate distributions of the first and second metal in a way that indicates efficient use of the metal. More particularly, in general, according to various modalities, the ratio of the maximum signal of the first metal to the maximum signal of the second metal over the scanning region is at least about 1.5: 1, at least about 2: 1, or at least about 2.5: 1. Typically, the ratio of the maximum signal of the first metal to the maximum signal of the second metal over the scan region is at least about 3: 1, at least about 4: 1, or at least about 5: 1.

It is to be understood that the efficient use of metal can be indicated by identifying at least one particle on the surface of the catalyst support having a noble metal distribution (second) characterized as described above. That is, the population of metal particles on the surface of the catalyst support can include both particles that satisfy one or more noble metal distributions characteristic of and those that do not. However, the use of metal is increased as the proportion of particles showing these preferred noble metal characteristic distributions increases and, typically, a plurality of metal particles will have these characteristics. More typically, the distribution of the second metal of each of a portion of particles (numerical base) on the surface of the support, indicates an efficient use of metal. Generally, at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, or at least about 25% of the metal particles meet the requirements distribution characteristics of the second metal. Typically, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60% , or at least about 65% of the metal particles meet the distribution characteristics of the second metal. The proportion of metal particles that satisfies one or more of the noble metal distribution characteristics is, in a way, dependent on the particular combination of the first metal and the second metal. For example, catalysts prepared with copper and platinum as the first and second metals, respectively, have been observed to produce catalysts in which a large portion of metal particles on their surface have these preferred noble metal distribution characteristics. Therefore, in these and other preferred embodiments, at least about 70%, at least about 75%, at least about 85%, or at least about 90% of the metal particles on the surface of the support satisfy one or more distribution characteristics of the second metal, determined by in-line scanning analysis of EDX.

As noted earlier, in various embodiments of the present invention (for example, where copper is the first metal and platinum is the second metal) the shell rich in the second metal can provide relatively low coverage of the core rich in the first metal, and during the subsequent use of the catalyst, the particle structure may deviate in order to increase the coverage of the core rich in the first metal by the shell containing the second metal. This deviation generally comprises leaching the first metal from metal particles on the support surface. The second metal can be removed or leached from the particles, but to a lesser extent than the first metal is removed from the particles. It has been observed that this behavior provides a shift towards the preferred atomic ratios of the first metal to the second metal.

The platinum-iron catalysts of the present invention have been observed to behave as described. That is, during use, iron and platinum can be leached from metal particles on the surface of the catalyst and, more particularly, iron is leached from the particles to a greater degree than platinum. Leaching in this way can proceed according to the self-correction mechanism described above with respect to copper-platinum catalysts. However, leaching can also proceed to form platinum-iron particles of advantageous structures. Instead of compensating for a relatively low excess of the first metal to the second metal, in order to provide a structure in which the atomic ratio of the first metal to the second metal is in a suitable excess, the leaching of the first metal predominates over any leaching of the second metal to such a degree that one or more particles are supplied so as to exhibit minimal excess, if any, from the first metal to the second metal. In fact, in various embodiments, a catalyst structure that exhibits an excess of second metal for the first metal is achieved. Although these particles cannot include an alloy rich in the first metal or a core rich in the first metal, at least partially surrounded by a shell rich in the second metal, they do not, however, provide a better use of metal.

In several of these embodiments, the metal particles on the surface of the catalyst are in the form of a structure comprising a discontinuous shell comprising a layer of atoms of the first metal and a layer of atoms of the second metal (for example, monolayer) in the surface of the atoms of the first metal. Reference to a shell in relation to these modalities does not indicate the presence of a continuous or discontinuous shell that surrounds a relatively continuous core. Instead, the shell refers to the overall structure of the resulting particle. The shell structure may surround an interior region, including the first metal, but the inner areas of the shell structure are not in the form of a core rich in the first relatively continuous metal, surrounded by outer regions of the shell structure. The discontinuous porous shell generally comprises pores and, more particularly, nanopores (ie pores with a size, in their maximum dimension of about 1 to about 6 nanometers (nm), or from about 2 to about 5 nm). In this way, the shell structure can be referred to as a discontinuous nanoporous shell. According to such modalities, the atomic ratio of iron (first metal) to platinum (second metal) is generally less than 1: 1, typically from about 0.25: 1 to about 0.9: 1, most typically from about 0.4: 1 to about 0.75: 1 and, more typically, from about 0.4: 1 to about 0.6: 1 (e.g., about 0.5: 1). In addition, according to these modalities, the layer or regions of the first metal generally have a thickness of no more than about 5 atoms of the first metal, typically no more than about 3 atoms of the first metal, and yet more typical, no more than about 2 atoms of the first metal. Additionally or alternatively, the layer or regions of atoms of the second metal generally have a thickness of no more than about 5 atoms of the second metal, typically no more than about 4 atoms of the second metal, more typically no more than than about 3 atoms of the second metal and, more typically, no more than about 2 atoms of the second metal.

Extensive leaching of metal from catalyst particles to form platinum-iron shell particles has been observed to occur during use under certain conditions (for example, acidic conditions that prevail during oxidation of PMIDA). Experimental evidence indicates that catalysts including platinum-iron shell particles are effective for use, for example, in liquid phase oxidation of PMIDA. Thus, instead of simply relying on the formation of the shell structure during use, catalysts including platinum-iron shell particles can be prepared by a process generally as described above for the preparation of platinum-iron catalysts including treatment for the leaching of metals from one or more particles of the catalyst before or during the use of the catalyst. Generally, the treatment for metal leaching to form platinum-iron shell particles comprises contacting a platinum-iron catalyst with a suitable liquid medium. Typically, the liquid medium is acidic and the catalyst is contacted with the liquid medium at a temperature of at least about 5 ° C, or at least about 15 ° C.

III. Use of Oxidation Catalysts

The oxidation catalysts of the present invention can be used for liquid phase oxidation reactions, examples of such reactions include the oxidation of alcohols and polyols to form aldehydes, ketones and acids (for example, the oxidation of 2-propanol to form acetone, and oxidation of glycerol to form glyceraldehyde, dihydroxyacetone, or glycolic acid); the oxidation of aldehydes to form acids (e.g., the oxidation of formaldehyde to form formic acid, and the oxidation of furfural to form 2-furan carboxylic acid); the oxidation of tertiary amines to form secondary amines (for example, the oxidation of nitrilotriacetic acid (NTA) to form iminodiacetic acid (IDA)); the oxidation of secondary amines to form primary amines (for example, the oxidation of IDA to form glycine); and the oxidation of various acids (for example, formic acid or acetic acid) to form carbon dioxide and water.

The catalysts described above are especially useful in liquid phase oxidation reactions at pH levels below 7, and in particular, at pH levels below 3. Such a reaction is the oxidation of PMIDA or a salt thereof, for form a product of N - (phosphonomethyl) glycine in an environment with pH levels in the range of about 1 to about 2. This reaction is often carried out in the presence of solvents that solubilize noble metals and, in addition, reagents, intermediates or products often solubilize noble metals.

The oxidation catalyst disclosed herein is particularly suitable for catalyzing the liquid phase oxidation of a tertiary amine to a secondary amine, for example, in the preparation of glyphosate and related compounds and derivatives. For example, the tertiary amine substrate can correspond to a compound of formula I having the structure:

R ³ O.

r ⁴ o '

(Formula I) where R ¹ is selected from the group consisting of R ⁵ OC (O) CH2- and R ⁵ OCH2CH ₂ -, R ₂ is selected from the group consisting of R ₅ OC (O) CH ₂ -, R ⁵ OCH2CH2-, hydrocarbyl, substituted hydrocarbyl, acyl, -CHR6PO3R ⁷ R ⁸ , and CHR ⁹ SO3R ¹⁰ , R ⁶ , R ⁹ and R ¹¹ are selected from the group consisting of hydrogen, alkyl, halogen and -NO2, and R ³ , R ⁴ , R ⁵ , R ⁷ , R ⁸ and are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl and a metal ion. Preferably, R ¹ comprises R ⁵ OC (O) CH2-, R ¹¹ is hydrogen, R ⁵ is selected from hydrogen and an acceptable cation in agronomy and R ² is selected from the group consisting of R ⁵ OC ( O) CH ₂ -, acyl, hydrocarbyl and substituted hydrocarbyl.

As noted above, the oxidation catalyst of the present invention is particularly suitable for catalyzing the oxidative cleavage of a PMIDA substrate to form N- (phosphonomethyl) glycine product. In one embodiment, the catalyst is effective for oxidizing the formaldehyde by-product to formic acid, carbon dioxide and / or water. More particularly, it is currently believed that the catalysts of the present invention can provide improvements in the activity for the oxidation of PM IDA, formaldehyde, and / or formic acid when compared to conventional catalysts containing noble metal, either generally or on a weight basis of metal per unit.

As is recognized in the art, liquid-phase oxidation of iminodiacetic N- (phosphonomethyl) substrates can be carried out in a batch, semi-batch or continuous reactor system containing one or more oxidation reaction zones. The oxidation reaction zone (s) can be suitably supplied by various reactor configurations, including those that have back-mixing characteristics, in the liquid phase and, optionally, in the gas phase as well, and those that have characteristics of piston flow. Suitable reactor configurations having back-mixing characteristics include, for example, stirring tank reactors, loop reactors with ejector nozzles (also known as loop reactors with Venturi type ejectors) and fluidized bed reactors. Suitable reactor configurations having piston flow characteristics include those that have a packaged or fixed bed catalyst (e.g., drip bed reactors and packaged bubble column reactors) and bubbling slurry column reactors. Fluidized bed reactors can also be operated in a manner that has piston flow characteristics. The configuration of the oxidation reactor system, including the number of oxidation reaction zones and oxidation reaction conditions is not of critical importance to the practice of the present invention. Oxidation reactor systems and oxidation reaction conditions suitable for liquid phase catalytic oxidation of an iminodiacetic N- (phosphonomethyl) substrate are well known in the art and described, for example, by ebner et al., US Patent no. °

6,417,133, by leiber et al., U.S. Patent No. 6,586,621, and by Haupfear et al.,

U.S. Patent No. 7,015,351, the entire descriptions of which are incorporated herein by reference.

The description below discloses, in particular, the use of catalysts described above, which act as the catalyst to effect the oxidative dividing of a PMIDA substrate to form an N (phosphonomethyl) glycine product. It must be recognized, however, that the principles disclosed below are generally applicable to other liquid phase oxidation reactions, especially those at pH levels below 7 and those involving solvents, reagents, intermediates or products that solubilize noble metals.

To start the PMIDA oxidation reaction, it is preferable to load the reactor with PMIDA substrate, catalyst, and a solvent, in the presence of oxygen. The solvent is most preferably water, although other solvents (for example, glacial acetic acid) are also suitable.

The reaction can be carried out in a wide variety of 15 batch, semi-batch and continuous reactor systems. The reactor configuration is not critical. Suitable conventional reactor configurations include, for example, agitation tank reactors, fixed bed reactors, drip bed reactors, fluidized bed reactors, bubble flow reactors, piston flow reactors and parallel flow reactors.

When conducted in a continuous reactor system, the residence time in the reaction zone can vary widely depending on the specific catalyst and the conditions employed. Typically, the residence time can range from about 3 to about 120 minutes. Preferably, the residence time is about 5 to about 90 minutes, and more preferably about 5 to about 60 minutes. When conducted in a batch reactor, the reaction time typically varies over the range of about 15 to about 120 minutes. Preferably, the reaction time is about 20 to about 90 minutes, and more preferably about 30 to about 60 minutes.

In a broad sense, the oxidation reaction can be practiced according to the present invention over a wide range of temperatures, and at pressures ranging from a pressure above atmospheric pressure to a pressure below atmospheric pressure. The use of mild conditions (for example, room temperature and atmospheric pressure) has obvious commercial advantages in that cheaper equipment can be used. However, operating at higher temperatures and pressures higher than atmospheric pressure, by increasing the capital requirements, there is a tendency to improve the phase transfer between the liquid and the gaseous phase and to increase the oxidation reaction rate of PM IDA.

Preferably, the PM IDA oxidation reaction is conducted at a temperature of about 20 to about 180 ° C, more preferably from about 50 to about 140 ° C, and more preferably from about 80 to about 110 ° Ç. At temperatures above 180 ° C the raw materials tend to start to decompose slowly.

The pressure used during PMIDA oxidation generally depends on the temperature used. Preferably, the pressure is sufficient to prevent the reaction mixture from bubbling. If an oxygen-containing gas is used as the oxygen source, the pressure is also preferably suitable to cause the oxygen to dissolve in the reaction mixture at a sufficient rate so that PMIDA oxidation is not limited due to an insufficient supply of oxygen. The pressure is preferably at least equal to atmospheric pressure. More preferably, the pressure is from about 30 to about 500 psig, and more preferably from about 30 to about 130 psig.

The concentration of the catalyst prepared according to the present invention in the reaction mixture is preferably from about 0.1 to about 10% by weight ([mass of catalyst / total reaction mass] x 100%). More preferably, the concentration of the catalyst is preferably between about 0.1 to about 5% by weight, even more preferably from about 0.2 to about 5% by weight and, more preferably, about 0.3 to about 1.5% by weight. Concentrations greater than about 10% by weight are difficult to filter.

On the other hand, concentrations below about 0.1% by weight tend to produce unacceptably low reaction rates.

As noted, catalysts prepared according to the methods of the present invention provide efficient use of metal. Thus, the catalysts of the present invention can provide sufficient activity at lower catalyst loads as compared to the charges associated with conventional catalysts containing noble metals. Consequently, the catalyst loads according to the present invention can suitably be at the lower limit, or close to the lower limit, of the ranges noted above. However, it should be understood that the use of a smaller catalyst load is not a critical aspect of the present invention. In fact, a further aspect of the present invention involves the use of catalysts of the present invention in fillers similar to those associated with conventional catalysts containing a noble metal in providing improved catalytic activity based on improvements in the use of metal.

The concentration of PMIDA substrate in the feed stream is not critical. The use of a saturated solution of PMIDA substrate in water is preferred, although for reasons of ease of operation, the process is also operable with higher or lower concentrations of PMIDA substrate in the feed stream. If the catalyst is present in the reaction mixture in a finely divided form, it is preferable to use a concentration of reagents such that all reagents and the N- (phosphonomethyl) glycine product remain in solution so that the catalyst can be recovered for reuse, for example. example, by filtration. On the other hand, higher concentrations tend to increase the total productivity of the reactor. Alternatively, if the catalyst is present as a stationary phase through which the reaction medium and oxygen source are passed, it may be possible to use higher concentrations of reagents in such a way that a product portion of N- (phosphonomethyl) glycine precipitates.

Typically, a concentration of PMIDA substrate up to about 50% by weight ([PMIDA substrate mass / total reaction mass] x 100%) can be used (especially at a reaction temperature between about 20 to about 180 ° C). Preferably, a PMIDA substrate concentration of up to about 25% by weight is used (particularly at a reaction temperature of about 60 to about 150 ° C). More preferably, a PMIDA substrate concentration of about 12 to about 18% by weight is used (particularly at a reaction temperature of about 100 to about 130 ° C). PMIDA substrate concentrations below 12% by weight can be used, but are less economical because a relatively low product load of N- (phospho10 nomethyl) glycine is produced in each reactor cycle and more water has to be removed and more energy used per product unit of N- (phosphonomethyl) glycine produced. Relatively low reaction temperatures (ie, temperatures below 100 ° C) often tend to be less advantageous because the solubility of the PMIDA substrate and that of the product of

N- (phosphonomethyl) glycine are both relatively low at such temperatures.

The oxygen source for the PMIDA oxidation reaction can be any gas that contains oxygen, or a liquid that comprises dissolved oxygen. Preferably, the oxygen source is an oxygen-containing gas. As used herein, an oxygen-containing gas is any gas mixture containing molecular oxygen which may optionally comprise one or more diluents that are not reactive with oxygen or the reagent or product under the reaction conditions.

examples of such gases are air, pure molecular oxygen, or molecular oxygen, diluted with helium, argon, nitrogen or other non-oxidizing gases. For economic reasons, the most preferred oxygen source is air, oxygen-enriched air, or pure molecular oxygen.

Oxygen can be introduced by any conventional means to the reaction medium in a way that maintains the oxygen concentration in the reaction mixture at a desired level. If an oxygen-containing gas is used, it is preferably introduced into the reaction medium in a way that maximizes the contact of the gas with the reaction solution. Such contact can be obtained, for example, by dispersing the gas through a diffuser, such as a porous frit or by stirring, stirring, or by other methods known to those skilled in the art.

The oxygen feed rate is preferably such that the oxidation reaction rate of PMIDA is not limited by the oxygen supply. If the dissolved oxygen concentration is too high, however, the catalyst surface tends to become disadvantageously oxidized, which in turn tends to lead to more leaching of noble metal present in the catalyst and decreased formaldehyde activity (which , in turn, leads to more NMG being produced). Generally, it is preferred to use an oxygen feed rate, such that at least about 40% of the oxygen is used. Most preferably, the oxygen feed rate is such that at least about 60% of the oxygen is used. Even more preferably, the oxygen feed rate is such that at least about 80% of the oxygen is used. Most preferably, the rate is such that at least about 90% of the oxygen is used. As used here, the percentage of oxygen used is equal to: (total oxygen consumption rate / oxygen supply rate) x 100%. The term total oxygen consumption rate means the sum of: (I) the oxygen consumption rate (Ri) of the oxidation reaction of the PMIDA substrate to form a product of N- (phosphonomethyl) glycine and formaldehyde, (ii) a oxygen consumption rate (Rii) of the formaldehyde oxidation reaction to form formic acid, and (iii) the oxygen consumption rate (Riii) of the formic acid oxidation reaction to form carbon dioxide and water.

In various embodiments of this invention, oxygen is fed into the reactor as described above, until the substrate volume of PMIDA has been oxidized, and then a reduced oxygen feed rate is used. This reduced feed rate is used, preferably, after about 75% of the PMIDA substrate has been consumed. Most preferably, the reduced feed rate is used after about 80% of the PMIDA substrate has been consumed. When oxygen is supplied as pure oxygen or oxygen-enriched air, a reduced feed rate can be achieved by purging the reactor with (not enriched) air, preferably at a volumetric feed rate that is not greater than the rate volume to which the molecular oxygen or air enriched with pure oxygen was fed before the air purge. The reduced rate of oxygen supply is preferably maintained for about 2 to about 40 minutes, more preferably for about 5 to about 20 minutes, and most preferably for about 5 to about 15 minutes. While oxygen is being fed at a reduced rate, the temperature is preferably kept at the same temperature or below the temperature at which the reaction was conducted before the air purge. Likewise, the pressure is maintained at the same or at a lower pressure than the pressure at which the reaction was conducted before purging the air. The use of a reduced rate of oxygen supply near the end of the PMIDA reaction allows the amount of residual formaldehyde present in the reaction solution to be reduced without producing harmful amounts of AMPA through the oxidation of the N- (phosphonomethyl) product ) glycine.

Reduced noble metal losses can be observed with this invention if a sacrificial reducing agent is maintained or introduced into the reaction solution. Suitable reducing agents include formaldehyde, formic acid, and acetaldehyde. More preferably, formic acid, formaldehyde, or mixtures thereof are used. Experiments conducted in accordance with the present invention indicate that if small amounts of formic acid, formaldehyde, or a combination of them are added to the reaction solution, the catalyst will preferably oxidize formic acid or formaldehyde before oxidizing the substrate of PMIDA and, subsequently, will be more active in effecting the oxidation of formic acid and formaldehyde during the oxidation of PMIDA. Preferably, between about 0.01 to about 5% by weight ([mass of formic acid, formaldehyde or a combination thereof / total reaction mass] x 100%) of sacrificial reducing agent is added, more preferably, from about 0.01 to about 3% by weight of the sacrificial reducing agent is added, and more preferably from about 0.01 to about 1% by weight of the sacrificial reducing agent is added.

In certain embodiments, unreacted formic acid and formaldehyde are recycled back to the reaction mixture for use in subsequent cycles. In this example, an aqueous recycling stream comprising a solution of formaldehyde and / or formic acid can also be used to solubilize the PMIDA substrate in subsequent cycles. This recycling stream can be generated by the evaporation of water, formaldehyde and formic acid from the oxidation reaction mixture in order to concentrate and / or crystallize the N (phosphonomethyl) glycine product. The top condensate containing formaldehyde and formic acid may be suitable for recycling.

Typically, the concentration of N- (phosphonomethyl) glycine in the product mixture can be as high as 40% by weight, or higher. Preferably, the concentration of N- (phosphonomethyl) glycine is about 5 to about 40%, more preferably about 8 to about 30%, and even more preferably about 9 to about 15%. The concentrations of formaldehyde in the product mixture are typically less than about 0.5% by weight, more preferably less than about 0.3%, and even more preferably less than about 0.15%.

After oxidation, the catalyst is preferably subsequently separated by filtration. The N- (phosphonomethyl) glycine product can then be isolated by precipitation, for example, by evaporating a portion of the water and cooling.

In certain embodiments, it must be recognized that the catalyst of the present invention has the ability to be reused over several cycles, depending on how oxidized its surface becomes with use. Even after the catalyst has become very oxidized, it can be reused when reactivated. To reactivate a catalyst with a strongly oxidized surface, the surface is preferably washed first to remove organic products from the surface. Then, preferably, it is reduced in the same way that a catalyst is reduced after the noble metal is deposited on the surface of the support, as described above.

Noble metal-containing catalysts including a porous treated substrate prepared by the present method can also be used in combination with a supplemental promoter, as described, for example, in US Patent No. 6,586,621, US Patent No. 6,963,009, the complete contents of which are here incorporated by reference, for all relevant purposes.

The N- (phosphonomethyl) glycine product prepared according to the present invention can be further processed according to many methods well known in the art, to produce the agronomically acceptable salts of N- (phosphonomethyl) glycine, commonly used in compositions glyphosate herbicides. As used herein, an agronomically acceptable salt is defined as a salt that contains a cation (s) that allows the agriculturally and economically useful herbicidal activity of an N- (phosphonomethyl) glycine anion. This cation can be, for example, an alkali metal cation (for example, a sodium or potassium ion), an ammonium ion, an isopropyl ammonium ion, a tetraalkylammonium ion, a trialkyl sulfonium ion, a protonated primary amine, protonated secondary amine, or protonated tertiary amine.

IV, Additional Modalities

A. The pore blockage

With regard to the disposition or deposition of a pore blocking compound within the pores of the substrate as detailed here elsewhere, it should be noted that the present invention is not limited to the disposition or deposition of a pore blocking compound within the pores smaller substrates (for example, micropores). That is, several embodiments of the present invention are directed to the disposition or deposition of a pore blocker within the pores of a larger or intermediate size range. In this way, various embodiments of the present invention provide additional opportunities to control the pore sizes that are blocked (i.e., other opportunities to control, or adjust the pore blockage). For example, in addition to micropores, the porous carbon supports that can be treated by the present method have larger pores (for example, pores larger than about 20Â to about 3000Â).

The disposition or deposition of a pore blocking agent within the pores of a size above the micropore size range generally proceeds according to the method described above. For example, the substrate can be contacted with the pore blocking compound and / or one or more precursors. Additionally, still according to the method described above, the pore blocker can be kept within the target pores by virtue of exhibiting at least one dimension larger than the openings of the target pores. And regardless of whether the pore blocking agent is introduced into the target pores or is formed in situ, the pore blocker can be kept within the target pores by virtue of a conformational arrangement of the pore blocker.

As noted above, when relatively small pores are targeted by the pore blocker, the pore blocker can enter the non-target pores and subsequently leave them (for example, due to contact with a liquid washing medium). It should be noted that a pore blocker that targets a large and / or intermediate size cannot enter the pores smaller than the target pores. However, this has no impact on the goal of blocking large and / or intermediate pores.

It is currently believed that a variety of compounds are suitable as pore blocking compounds for the purpose of blocking pores above the micropore size range. For example, the pore blocker can be selected from the group consisting of various hydrophilic polymers (for example, polyethylene glycols of various), and combinations thereof.

In various embodiments, the large and / or intermediate pore blocker may comprise the product of a reaction between one or more precursors of pore blocking compounds. For example, it has been observed that the coupling product of a ketone and a dihydric alcohol can be used as a pore blocker.

As with the micropores as noted above, it is believed that the presence of the pore blocking compound within the target pores outside the micropore domain will cause at least a portion of the blocked pores to appear as a non-porous portion of the substrate during area measurements. surface, thereby reducing the proportion of surface area that could otherwise be provided by target pores if they were not blocked. It is currently believed that this blocking of target pores provides a reduction in the surface area of the treated substrate provided by the target pores. For example, in various embodiments, the surface area of the treated substrate provided by the pores outside (ie, above) the micropore size range is generally no more than about 80% or no more than about 70% of the surface area of the substrate supplied by these pores before treatment. Typically, the surface area of the treated substrate provided by target pores is not more than about 60% and more typically not more than about 50% of the substrate surface area provided by these pores prior to treatment.

B. Porous Blocking of the Porous Catalyst

As noted, the persistence of the pore blocker on treated substrates of the present invention is not critical to providing the advantages described above (for example, a reduced proportion of metal crystallites on the surface of a porous carbon support between relatively small pores of the surface of the substrate). And it is currently believed that the pore blocker is most likely to decompose and / or otherwise removed from the substrate surface prior to calcination. In various alternative embodiments, methods for treating porous substrates can be applied to the treatment of finished catalysts. For example, catalysts containing a noble metal deposited on a carbon support can be treated by depositing a pore blocker on the surface of the catalyst inside their relatively small pores. It is currently believed that the presence of the pore blocker within the relatively small pores may promote the preferential contact of reagents with the deposited metal between the pore regions with large and intermediate size within which the deposited metal is more accessible to the reagents. In this way, the conversion of reagents into products can be promoted by reducing the proportion of reagents that contact the deposited metal between the relatively small porous regions in which the deposited metal may be relatively inaccessible to the reagents. As an additional example, it is currently believed that the treatment of carbon supported catalysts suitable for the preparation of DSIDA from DEA, according to the detailed methods, provides catalysts including a reduced proportion of exposed noble metal and, as a result, , reduced by-product (eg glycine and / or oxalate). However, it should be understood that the treatment of the finished catalyst (i.e., carbon or a metal containing coal with one or more metals deposited in it) is not a critical aspect of the invention and that catalysts prepared using substrates treated by the present methods have proven be effective catalysts.

C. Different carbon supports

In addition to the treatment of porous carbon supports, as detailed above, the method of the present invention for blocking certain pores of a substrate can be used to treat non-carbonaceous supports. More particularly, the methods described herein can be used for the treatment of porous metal alloys, often referred to as metal sponges. Metal sponge-type alloys that can be treated by the present method are described, for example, in US Patent No. 5,627,125, US Patent No. 5,916,840, US Patent No. 6,376,708, and in US Patent No. 6,706,662, the complete contents of which being incorporated herein by reference, for all relevant purposes. It is currently believed that treated substrates containing metal may exhibit one or more of the properties mentioned above with respect to treated porous carbon substrates.

D. Preparation of Carboxylic Acids

In addition to the oxidation of PM IDA as detailed here elsewhere, it is currently believed that catalysts including treated substrates prepared by the present method may be suitable for use in other reactions. For example, catalysts including treated substrates prepared by the present method can be used in the preparation of carboxylic acids including, for example, the preparation of iminodiacetic disodium acid (DSIDA) by the dehydrogenation of diethanolamine (DEA). More particularly, catalysts including treated substrates of the present invention can address one or more situations that can be observed with conventional catalysts used in the preparation of carboxylic acids such as DSIDA. For example, suitable catalysts often include copper deposited on the surface of a carbon support having a noble metal (for example, platinum or palladium) on its surface. It is currently believed that at least a portion and possibly a significant fraction of the noble metal may remain exposed after copper deposition. Excessive exposed noble metal is undesirable since it is believed to promote the formation of several unwanted by-products (eg, glycine and oxalate). It is believed that a substantial portion, if not practically all of the exposed noble metals, are on the surface of the support within relatively small pores that are inaccessible to copper during its deposition. Other suitable catalysts for the preparation of carboxylic acids include copper deposited on the surface of metal-containing sponges (for example, containing nickel). As with the noble metals exposed on the surface of carbon supported catalysts, it is assumed that the metal support surface that is not coated by copper within the relatively small pores of the metal sponge support contributes to the formation of unwanted by-products. It is currently believed that the selective blocking of relatively small pores of substrates, according to the methods described here, can be used to prepare catalysts supported on carbon and effective metals that can address one or more of the situations mentioned above.

The preparation of DSIDA from DEA using a catalyst comprising a substrate treated as detailed herein generally proceeds in accordance with methods known in the art including, for example, US Patent No. 5,627,125, US Patent No. 5,916,840, US Patent No. 6,376,708, and US Patent No. 6,706,662, the complete contents of which are hereby incorporated by reference, for all relevant purposes.

The present invention is illustrated by the following examples, which are for the purpose of illustration only and should not be considered as limiting the scope of the invention or the way in which it can be practiced.

Examples

The following non-limiting examples are provided to better illustrate the present invention.

I. The clogging of pores

Example 1

Three carbon supports were treated to determine the effectiveness of candidate pore blocking compounds. Support A had a total surface area of Langmuir of approximately 1500 m ² / g (including total surface area of micropores of approximately 1279 m ² / g and a total surface area of approximately 231 m ² / g). Support B had a total surface area of Langmuir of approximately 2700 m ² / g (including total surface area of micropores of approximately 1987 m ² / g and a total surface area of approximately 723 m ² / g). Support C had a total surface area of Langmuir of approximately 1100 m ² / g (including total surface area of micropores of approximately 876 m ² / g and a total surface area of macropores of approximately 332 m ² / g).

The candidate pore blocking compounds were 1,4cyclohexanedione, ethylene glycol, and the diketal product of a coupling reaction between 1,4-cyclohexanedione and ethylene glycol (i.e., 1,4-cyclohexanedion bis (ethylene ketal)).

Support samples (30 g) were contacted with a solution of 1,4-cyclohexanedione in ethylene glycol (6g / 40g) at approximately 25 ° C for approximately 60 minutes. The pH of the slurry was adjusted to approximately 1 by the addition of concentrated hydrochloric acid and stirred by stirring for approximately 60 minutes. The slurry pH was then adjusted to approximately 8.5 by adding 50% by weight of sodium hydroxide solution. The slurry was then filtered to isolate the treated support, which was washed using deionized water at a temperature of approximately 90 ° C. (mechanism one).

Support samples (2 g) were also contacted with a solution of 1,4-cyclohexanedione bis (ethylene ketal) in water (0.6 g / 40 g) at approximately 25 ° C for approximately 60 minutes, (mechanism 2).

As controls, samples of carbon A were also treated, separately, by contact with (1) ethylene glycol and (2) 1,4-cyclohexanedione.

The treated substrates were analyzed by the well-known Langmuir method to determine their surface area (AS) profiles (for example, total surface area, surface area attributed to the micropore, and a surface area attributed to the macropores). The results are shown in table 1.

Table 1

Support Mechanism Microporous% SA original Macropore% AS original Carbon A a 24.2 74.9 Carbon A Two 34.4 70.9 Carbon A Control one 93.7 98.7 Carbon A Control two 68.9 94.4 Carbon B a 55.6 78.7 Carbon B Two 65.4 81.5 Carbon C a 17.9 76.8 Carbon C Two 22 72.3

As shown, both mechanism one and mechanism two provided a reduction in the surface areas of the micropores and macropores and for each of the AC supports, and more particularly a greater reduction in the surface area of the micropores compared to the reduction in the surface area of the macropores ( for example, a three times greater reduction in the surface area of the micropores). It is believed that the percentage of reduction in surface area for carbon B is less than that observed for the other two carbons because of its larger surface area. However, it should be noted that the percentage of reduction in the surface area of the micropores to carbon B, despite this, corresponds to an absolute reduction of approximately 900 m ² / g.

The carbon A control test with ethylene glycol provided a minimal reduction in the surface areas of the micropores and macropores and, while the control tests with 1,4-cyclohexanedione provided a greater reduction in the surface areas of the micropores and macropores, but in degree much smaller than that associated with both mechanism one and mechanism two. Thus, it is believed that the components combine to form the pore blocking compound that provides a greater reduction in surface area than any component individually or the cumulative reduction provided by each.

Example 2

Carbons A, B, and C (30 g) described in example 1 were each treated by contact with solutions of 1,4-cyclohexanedione in ethylene glycol (6 g / 40 g) at approximately 25 ° C for approximately 60 minutes. Each carbon was also treated by contact with solutions of 1,3cyclohexanedione in ethylene glycol (1g / 50 g) at approximately 25 ° C for approximately 120 minutes. Carbon C was also treated by contact with a solution of 1,4-cyclohexanedione in 1,2-propanediol (1g / 50 g) at approximately 25 ° C for approximately 60 minutes. The results of the analysis of the surface area are shown in Table 2. As shown, each combination of dione and diol provided a reduction in the surface areas of the micropores and macropores and, more particularly, a preferential reduction in

100 surface area of micropores. Table 2

Sample Diona Diol % Of the original micropore % Of the original macropore Carbon A 1,4-disubstituted Ethylene glycol 22.6 75.8 Carbon A 1,3-disubstituted Ethylene glycol 58.4 84 Carbon B 1,4-disubstituted Ethylene glycol 55.6 78.7 Carbon B 1,3-disubstituted Ethylene glycol 32.2 39.8 Carbon C 1,4-disubstituted Ethylene glycol 17.9 76.8 Carbon C 1,3-disubstituted Ethylene glycol 45 75.6 Carbon C 1,4-disubstituted 1,2-Propanediol 14.4 67.5 Carbon C 1,3-disubstituted 1,2-Propanediol 56.1 80.7

Example 3

This example provides transmission electron microscopy (TEM) results for a platinum carbon catalyst prepared using Carbon B treated as described in example 1 (a mechanism). The catalyst contained approximately 5% by weight of platinum and was prepared, in general, as detailed here (for example, by deposition in liquid phase of platinum support on carbon support), followed by treatment at elevated temperatures in a non-oxidizing environment . For comparison, a catalyst including 5 wt% platinum on Carbon B that was not treated was also analyzed. TEM analysis was generally conducted as described by Wan et al., In International Publication in WO 2006/031198.

The results for the catalyst, including the treated and untreated carbons are shown in figures 3A / 5A and 3B / 5B, respectively. These results suggest a reduction in relatively small platinum-containing particles (for example, having a particle size of less than 4 nm) for the catalyst prepared using the treated support.

101

The TEM results correspond, in general, to the high density regions of the substrates including mainly micropores and these results indicate the highest platinum density among these regions for the catalyst, including the untreated support.

Example 4

This example provides results of the analysis of the surface area for a carbon support of the type described in US patents nos. 4,624,937 and 4,696,771 by chou et al. (designated MC-10) treated in accordance with the present invention. Support samples were treated according to mechanism one and mechanism two described above in example 1. The support has an initial Langmuir surface area of approximately 1987 m ² / g and an initial Langmuir surface area of approximately 723 m ² / g. The results of retaining the surface area of the micropores and macropores for the treated substrates are shown in table 3.

Table 3

Support Mechanism of Obstruction % Of the original micropore Macropore% AS original MC-10 a 55.6 78.7 MC-10 Two 65.4 81.5

Figures 4A and 4B provide pore volume data for untreated and treated MC-10 supports.

Example 5

This example provides results of the carbon monoxide (CO) chemisorption analysis for the platinum catalysts of example 4. CO chemisorption is an appropriate method of analysis to estimate the proportion of exposed metal, and the analysis was conducted, in general , in accordance with protocol A described in example 67 here and Example 23 of WO 2006/031938, incorporated herein by reference.

The results are shown in table 4. The lower CO chemisorption for the catalyst including a treated carbon support (38.6 and 43.3 pmol CO / gram versus 54.7 pmol CO / gram catalyst)

102 indicate a reduced proportion of noble metal exposed to the platinum containing catalyst prepared using the treated carbon support.

Table 4

Catalyst Cycle 2 μιτιοΙ of CO / g of catalyst Pt in MC-10 regular 54.7 Pt in modified MC-10 38.6 / 43.3

Example 6

Catalysts containing approximately 5 wt% Pt and approximately 0.5 wt% Fe were prepared, in general, as detailed here using untreated MC-10 carbon supports, and MC-10 carbon supports treated according to mechanism one and mechanism two described in example 1. These catalysts were tested for oxidation of PMIDA generally under the conditions indicated in example 7; the results are shown in table 5. The catalyst (1) included an untreated support. The catalysts (2) and (3) each included supports treated according to mechanism two detailed above in example 1. The catalyst (2) was prepared by a method that included filtration of the copper impregnated support before deposition platinum. The catalyst (3) was prepared by a method that did not include filtration of the copper impregnated support prior to platinum deposition (i.e., a one-pot method, as described in example 16).

Table 5

Catalyst (1) Race Number 1 2 3 4 5 6 Run Time, min 43.0 46.2 47.8 50.6 50.8 52.0 GLI% p 5.413 5,600 5.620 5,678 5.556 5,748 PMIDA% p 0.034 0.034 0.094 0.134 0.075 0.149 CH ₂ O% p 0.150 0.182 0.199 0.211 0.190 0.209 FORMIC% p 0.384 0.455 0.521 0.516 0.550 0.512 % P IDA 0.074 0.046 0.031 0.030 0.030 0.027 Pt in sunshine. (ppm) 0.03 0.07 0.07 0.09 0.08 0.12

103

Catalyst (1) Fe in sol. (Ppm) 5.4 1.9 2.3 2.3 2.0 1.6 Catalyst (2) Race Number 1 2 3 4 5 6 Run Time, min 43.0 45.1 48.8 47.2 47.6 48.3 GLI% p 5.363 5.543 5.541 5.592 5.557 5.604 PMIDA% p 0.036 0.097 0.022 0.129 0.154 0.177 CH ₂ O% p 0.125 0.143 0.105 0.139 0.144 0.169 FORMIC% p 0.389 0.456 0.435 0.479 0.484 0.508 % P IDA 0.086 0.052 0.041 0.033 0.031 0.028 Pt in sol. (Ppm) 0.05 0.14 Fe in sol. (Ppm) 6.3 1.9 Catalyst (3) Race Number 1 2 3 4 5 6 Run Time, min 43.0 46.3 46.7 48.5 48.5 49.8 GLI% p 5.475 5.596 5.543 5.649 5,790 5.980 PMIDA% p 0.058 0.141 0.167 0.136 CH ₂ O% p 0.175 0.171 0.192 0.191 0.208 0.222 FORMIC% p 0.466 0.550 0.547 0.565 % P IDA 0.073 0.044 0.030 0.026 0.025 0.022 Pt in sol. (Ppm) Fe in sol. (Ppm)

GLY = Glyphosate IDA = Iminodiacetic Acid

FORMIC = Formic Acid ppm = parts per Million

II. Catalyst precursors; Catalysts containing the first and the second metal; Catalyst Precursor Structures

The following examples describe the preparation of catalysts as detailed here, their testing by various characterization methods, and their testing for PMIDA oxidation. The following examples

104 also provide comparisons of catalysts prepared as detailed herein, and several other catalysts supported on metal-containing carbon. For example, the following examples provide comparisons for catalysts supported on carbon including Pt at 5% by weight, Fe at 0.1% by weight, and Co at 0.4% by weight, and the catalysts supported on carbon including Pt at 5% by weight and Fe at 0.5% by weight. These catalysts were prepared, in general, as described by WAN et al., In the international publication in WO 2006/031938.

Example 7

Catalysts prepared as described herein and comparison samples were tested under PMIDA oxidation conditions also generally described by Wan et al., In International Publication in WO 2006/031938. For example, PMIDA oxidation cycles were conducted in a glass reactor (200 ml commercially available from ACE Glass Inc.) containing a reaction mass (approximately 140 g), which included water (approximately 128 g), approximately 8.2% by weight of PMIDA (approximately 11.48 g), and a catalyst load of approximately 0.18% w (0.25 g). Oxidations were generally conducted at a temperature of approximately 100 ° C, under a pressure of about 60 psig, and an oxygen flow rate of approximately 100 cc / min. Unless otherwise noted, the reaction cycles were conducted to an end point determined by the production of approximately 1600 cm of carbon dioxide.

As described in the following examples and in the attached figures, several data were collected, including cycle time, metal leaching, residual formaldehyde content (HCHO), residual formic acid content (HCOOH), iminodiacetic acid formation (IDA) , formation of N-methyl-n (phosphonomethyl) glycine (nmg), total generation (CO2) of carbon dioxide, etc. Example 8

This example describes the preparation of a catalyst containing a nominal Pt content of approximately 2.5% by weight and a

105 nominal Cu content of approximately 5 wt% Cu on an activated carbon support with a Langmuir surface area of approximately 1500 m ² / g.

Activated carbon (approximately 10g), CuSO ₄ solution. 5H ₂ O (approximately 2.07 g), sucrose (approximately 5.67 g), degassed deionized water (approximately 30 g), and degassed 1M NaOH (70 g) were mixed in a partitioned beaker. The mixture was stirred at ambient conditions (approximately 25 ° C) for approximately 20 minutes. Formaldehyde (approximately 2.25 g of 37% by weight of the solution) was added to the mixture and the resulting mixture was heated to approximately 30 ° C and stirred for approximately 60 minutes.

The resulting slurry was filtered, washed with deionized water, degassed, resuspended in deionized water, and 1M HCl was added to provide a pH of approximately 1.5.

A solution of K ₂ PtCI ₄ (approximately 0.557 g) in degassed water (15 g) was added to the slurry, followed by continued stirring for 60 minutes under ambient conditions. The slurry was filtered, and the recovered metal impregnated support was washed with water, and dried under vacuum at approximately 110 ° C. A total of 12.12 g of support impregnated with dry metal was recovered. The elemental analysis indicated a composition of approximately 2.04% by weight of Pt and approximately 1.93% by weight of Cu on carbon.

The catalyst precursor was then heated at elevated temperatures to approximately 815 ° C in the presence of a stream of hydrogen / argon (2% / 98%; v / v) for approximately 60 minutes. The elementary analysis indicated final metal contents of approximately 2.34% wt of Pt and approximately 2.22% by weight of Cu.

As detailed below, the catalysts prepared by heating the metal-impregnated support at various temperatures were also tested. In addition, several supports impregnated with metal have also been tested for their catalytic activity.

106

Example 9. (Copper Plating at Room Temperature)

The preparation of 2% Pt ₃ Cu, 45% nominal on activated carbon catalyst: the following were added to a beaker with partition including approximately 10g of activated carbon: CuSO ₄ . 5H ₂ O solution (1.410 g), 3.866 g of sucrose, 90 g of degassed deionized water, and 5.974 g of NaOH 50% by weight. The mixture was stirred at approximately 22 ° C for approximately 10 minutes using a mechanical stirrer. After stirring, approximately 1.468g of 37% by weight formaldehyde solution was added and the resulting slurry was stirred at approximately 22 ° C for 60 minutes. The slurry was then filtered and washed twice on the filter, and then resuspended in water at a pH of approximately 2.0 by adding degassed 1.5M HCl. To this suspension was added a solution of K ₂ PtCI ₄ (0.444 g) in 15 g of degassed water, followed by stirring for approximately 60 minutes under ambient conditions. The slurry was then heated to approximately 65 ° C, followed by stirring for an additional 30 minutes. The resulting slurry was then filtered and washed with water and dried under vacuum at approximately 110 ° C. A total of 11.389g of dry material was recovered.

Example 10

Preparation of 2.5% Pt5Cu% nominal activated carbon: the following was added to approximately 10g of activated carbon in a beaker with partition: 2.072g of CuSO ₄ . 5H ₂ The solution, 5.694 g of sucrose, 30 g of degassed deionized water, and 70 g of degassed 1M NaOH was added. The mixture was heated to approximately 35 ° C using a mechanical stirrer. To this mixture was added 2.249 g of 37% w of formaldehyde solution, and the resulting slurry was heated to approximately 33-35 ° C, followed by continued stirring for 60 minutes. The slurry was filtered and washed with deionized water, degassed on a filter, and then resuspended in water at a pH of approximately 1.5 by the addition of 0.5M HCl. A solution of 0.557g of K ₂ PtCI ₄ in 15g of degassed water was then added to the slurry, followed by stirring

107 continued for 60 minutes under ambient conditions. Then, the slurry was heated to approximately 60 ° C and stirred for an additional 30 minutes. The resulting slurry was filtered and washed with water, and dried under vacuum at approximately 110 ° C. A total of 11.701 g of dry material was recovered. After heat treatment at a maximum temperature of approximately 950 ° C in the presence of an argon / hydrogen atmosphere (2% / 98%) (v / v) for 120 minutes, a final catalyst composition indicating a weight loss of approximately 12 , 1% by weight during heating was recovered.

Example 11 (No Washing after Copper Deposition)

The preparation of 2% Pt4% Cu nominal on activated carbon: the following was added to a beaker with partition including approximately 10g of activated carbon: 1,643g of CuSO ₄ solution. 5H ₂ O, 4.509 g of sucrose, 90 g of deionized water, degassed and 4.625 g of NaOH 50% w. The mixture was heated to approximately 30 ° C for approximately 10 minutes with a mechanical stirrer. To this slurry was added

I, 706g of 37% by weight of formaldehyde solution, and the resulting slurry was heated to approximately 30-35 ° C, followed by continued stirring for approximately 90 minutes. Then, the slurry was filtered and then, without washing, it was resuspended in water at pH 2.02 by the addition of degassed 1M HCl. A solution of 0.454g of K ₂ PtCI ₄ in 10g of degassed water was then added to the slurry, followed by continued stirring for 60 minutes under ambient conditions. The resulting slurry was then heated to approximately 60 ° C and stirred for an additional 30 minutes. This slurry was then filtered and washed with water, and dried under vacuum at approximately 110 ° C. A total of

II, 720 g of dry material was recovered. During heat treatment at a maximum temperature of approximately 950 ° C in the presence of an argon / hydrogen atmosphere (2% / 98%) (v / v) for approximately 120 minutes, the sample lost approximately 13.5% by weight.

Example 12

The preparation of 2% Pt 3.75% nominal Cu on activated carbon: the

The next 108 was added to a partitioned beaker including approximately 10 g of activated carbon 1.533 g of CuSO ₄ solution. 5H ₂ O, 4,210 g of sucrose, 90 g of deionized, degassed water and 4,300 g of NaOH 50% by weight was added. This mixture was heated to approximately 30 ° C and stirred for approximately 10 minutes using a mechanical stirrer. To this mixture was added 1.507 g of 37% by weight formaldehyde and the slurry was heated to approximately 30-35 ° C, followed by continued stirring for 60 minutes. The slurry was filtered and the recovered solids were washed once on the filter, and then re-fluidized in water to a pH of 1.97 by the addition of degassed 1M HCl. A solution of 0.452 g of K ₂ PtCl ₄ in 10 g of degassed water was then added to the slurry, followed by continued stirring for 60 minutes under ambient conditions. Then, the slurry was heated to approximately 60 ° C and stirred for an additional 30 minutes. The slurry was filtered and washed with water, dried in vacuo at approximately 110 ° C. A total of 11.413g of dry material was recovered. After heat treatment at a maximum temperature of approximately 950 ° C in the presence of 2% / 98% (v / v) H ₂ / atmospheric air for 120 minutes, the sample lost approximately 12.5% by weight. Example 13. (Deposition of Platinum at a Higher Temperature)

The preparation of 2% CuPt4% nominal activated carbon: the following were added to a beaker with partition including 10g of activated carbon: 1.645g of CuSO ₄ solution. 5H ₂ O, 4.502 g of sucrose, 90 g of degassed deionized water, and 4.636 g of 50% w / w NaOH. The mixture was stirred under ambient conditions for approximately 20 minutes with a mechanical stirrer. Then 1.721g of 37% formaldehyde was added and the slurry was heated to approximately 30-35 ° C, followed by continued stirring for 70 minutes. Then, the slurry was filtered and washed once with the filter, and then resuspended in water at pH 2.95 by the addition of degassed 1M HCl. A solution of 0.455g of K ₂ PtCI ₄ in 10g of degassed water was then added to the suspension, followed by continued stirring for 45 minutes at 40-45 ° C,

109 then, the slurry was heated to 60 ° C and stirred for an additional 30 minutes. The suspension was filtered and the recovered solids were washed with water, and dried in vacuo at approximately 110 ° C. A total of 12.008g of dry material was recovered. After heat treatment at a maximum temperature of approximately 950 ° C in the presence of (2% / 98%) (v / v) H2 / atmospheric air for approximately 120 minutes, the sample lost approximately 12.6% by weight.

Example 14

The preparation of 3% Pt6Cu% nominal on activated carbon: the following were added to a beaker with partition including 10g of activated carbon: 2.50g of CuSO ₄ solution. 5H ₂ O, 6,878 g of sucrose, 90 g of deionized, degassed water and 6,974 g of 50% NaOH. The mixture was heated to 30 ° C and stirred for approximately 10 minutes with a mechanical stirrer. Then, 2.444g of 37% formaldehyde was added and the slurry was heated to approximately 35-37 ° C, followed by continued stirring for 45 minutes. Then, the slurry was filtered and washed twice on the filter, and then resuspended in water at pH 1.97 by the addition of degassed 1M HCl. A solution of 0.700g of K ₂ PtCI ₄ in 20g of degassed water was then added to the suspension, followed by continued stirring for 60 minutes under ambient conditions. Then, the slurry was heated to 60 ° C and stirred for an additional 30 minutes. The slurry was then filtered and washed with water, and dried under vacuum at approximately 110 ° C. A total of 11.868g of dry material was recovered. After heat treatment at a maximum temperature of approximately 950 ° C in the presence of (2% / 98%) (v / v) H ₂ / atmospheric air for 120 minutes, the sample lost approximately 12.5% by weight.

Example 15 (Higher Platinum Content and Platinum Deposition Temperature)

Preparation of 4% Pt8Cu% nominal on activated carbon: the following were added to a beaker with partition including approximately 10g of activated carbon: 3,420g of CuSO ₄ solution. 5 H ₂ O, 9.375 g of sucrose, 100g deionized, degassed water and 9.675g of

110

50% NaOH. The mixture was heated to 30 ° C and stirred for 10 minutes with a mechanical stirrer. Then 3.331 g of 37% formaldehyde was added and the resulting slurry was heated to approximately 30-35 ° C, followed by continued stirring for 90 minutes. Then, the slurry was filtered and washed once with the filter, and then resuspended in water at pH 1.97 by the addition of degassed 1M HCl. A solution of 0.964g of K ₂ PtCl4 in 20g of degassed water was then added to the suspension, followed by continued stirring for 45 minutes at 45 ° C., Then, the slurry was heated to 60 ° C and stirred for a while. additional 45 minutes. The slurry was then filtered and washed with water, and dried under vacuum at approximately 110 ° C. A total of 12.283g of dry material was recovered. After heat treatment at a maximum temperature of approximately 950 ° C in the presence of 2% / 98% (v / v) H ₂ / atmospheric air for 120 minutes, the sample lost approximately 12.6% by weight. Example 16 (Recipe in a Vase)

The preparation of 2% Pt4% Cu nominal on activated carbon: the following were added to the beaker with partition including 10g of activated carbon: 1.644g of CuSO ₄ solution. 5H ₂ O, 4.509 g of sucrose, 90g deionized, degassed water and 4.715g of NaOH at 50% by weight. The mixture was heated to 30 ° C and stirred for 10 minutes with a mechanical stirrer. Then 1.736g of 37% formaldehyde was added and the slurry was heated to approximately 30-35 ° C, followed by continued stirring for 90 minutes. Then, the slurry was acidified to pH 2.98 by adding degassed 1M HCl. A solution of 0.454g of K ₂ PtCl4 in 10g of degassed water was then added to the slurry, followed by continued stirring for 60 minutes under ambient conditions. Then, the slurry was heated to 60 ° C and stirred for an additional 30 minutes. The slurry was then filtered and washed with water and dried under vacuum at approximately 110 ° C. A total of 11.864g of dry material was recovered. After heat treatment at approximately 950 ° C in the presence of an H ₂ / air (2% / 98%) (v / v) for 120 minutes, the sample lost approximately 12.2% weight.

111

Example 17

The preparation of 2% Pt4% Cu nominal on activated carbon: the following were added to a beaker with partition including 10g of activated carbon: 1.645g of CuSO ₄ solution. 5H ₂ O, 4.509 g of sucrose, 90g deionized, degassed water and 4.630g of 50% NaOH. The mixture was heated to 30 ° C and stirred for 10 minutes with a mechanical stirrer. Then 1.710g of 37% formaldehyde was added and the slurry was heated to approximately 30-35 ° C, followed by continued stirring for 90 minutes. Then, the slurry was filtered and washed once with the filter, and then resuspended in water at pH 2.01 by adding degassed 1M HCl. A solution of 0.570g of H ₂ PtCI ₆ in 15g of degassed water was then added to the suspension, followed by continued stirring for 60 minutes under ambient conditions. Then, the slurry was heated to 60 ° C and stirred for an additional 30 minutes. The slurry was then filtered and washed with water and dried under vacuum at approximately 110 ° C.

Example 18

The preparation of 2% Pt / 4% Cu nominal on activated carbon: the following were added to a beaker with partition including approximately 10g of activated carbon: 1.644g of CuSO ₄ solution. 5H2O. 4.517 g of sucrose, 70 g of deionized, degassed water and 4.701 g of 50% NaOH. The mixture was heated to 30 ° C and stirred for approximately 10 minutes with a mechanical stirrer. Then 1.705g of 37% formaldehyde diluted to 17.10g with degassed water was added, and the slurry was heated to approximately 30-35 ° C, followed by continued stirring for 60 minutes. Then, the slurry was filtered and washed once with the filter, and then resuspended in water at pH 1.99 by adding degassed 1M HCl. A solution of 0.460g of K ₂ PtCI ₄ in 10g of degassed water was then added to the suspension, followed by continued stirring for 60 minutes under ambient conditions. Then, the slurry was heated to 60 ° C and stirred for an additional 30 minutes. It was then filtered and washed with water,

112 and dried under vacuum at approximately 110 ° C. A total of 11.203g of dry material was recovered.

Example 19

This example details surface area (AS) and the analysis of CO chemisorption for catalysts with varying levels of platinum and copper prepared generally according to the conditions detailed here in example 7, and tested with PMIDA oxidation for 10 cycles generally under the conditions set out in example 7.

113

Table 6

10 cycles spent O CN O O lO lO CD treated 2% PtZ 3.75% Cu / C 1254 I 1034 19.7 216,215 134,627 55,397 16,678 7.468 1,680 0.315 0.050 216,215 OO B- 20.6 (0 O Q_ w s? <0 O) O CN (0 CN O B- B- B- O co X " fN X ^- co O O O sf CO co T " CO co CO O st O O O IO lO CO 4— · co 24C B- O 9.8 CD co CO 6.5 8’9 co St 66 CD CN O O CD CN sf CN CD CD M— » N- X " x- CN LO B- X " Ο O CN x— v- ω O O O CN s? CD co CD Ό O CN co CO CN CN Í3 O * 3 236 019 CO CD CN CN B- CN χ- * X— σί O O O lO CL 9.7 sf x ~ 33, CO sf 6.5 b- X ^- B- CO_ , 33 co O sf χ— 3.9 1O ~ CD X ^- CD CN O X- X- CN LO X " B- χ— Ο O CN x- partners 3-60 LO B·' CD O CD Ό O O LO O CO O Q_ CO CD CN O st χ— CO O co O O LO XT * the < LO O 70 76 O ‘68 CD ~ X " 9’8 3.8 95 , 25 , 22 00 ' '68 9.3 O CO CN CD r— CN X ^- mr LO χ— Ο O X- co ω O O IO O CN st B- CN B- Ό O co O B- CD CO χ— B- 53 _ 002 st LO O CO CO ιο CO O St O O io L0 ÉL O co CN 6’6 CO CN CD CO mr r- 6.9 X " LO 89 ' CO 00 ' 23, 4.6 O CD CN cb χ— CN LO X " B-" Χ “ ο O CN CN ω O O O CN CD O CD Ό O CO CN χ— co CO CN was going O * 3 208 CO B- mr B- CD Ο B- CN co O O io lO CL \ θ St 00 O θ O CN b- ~ CO 9’9 6.8 , 46 CO <Ο_ CD CN O O O CN lO n CD_ sf CD CO O X ^- cn CN CN T " LO r— τ- O O CN CN σ> O O go> m θ ' Q. AND O 3 O CD φ O CL AND lO Ν ' CO CO CO O Ό O O LO X " CO st LO 065 co O CO CO co C0 LO x— co O CN ÉL 301 6’6 io “ co B" st X " O co 96 ' CO Γ— x ~ CO O O io co CN b- ~ <D_ x-— v ~ CN x ~ CN CO X " B- Τ “ O O CN CN O d) st CO st Ό co co t— X ” LO CO (0 499 CO CD X " χ— co CO co O σ> CO X— X> • Φ 9'S co CD io ~ B- CD B- Γ- ιο CN ΙΟ χ— CD CO st O co CD < <c 2 X " x ~ CN B- CN X ^- CN O O CN z z < CD ω CM cn AND O ω O CM 04 ,AND - < AND O Q. O U_ O Ή O r (m - ♦ - · the Q. prayers O 1_ O CD CD AND 1 Ή O O 3 1 * - » Q. AND cn ΓΊ t O ICO Langm micro : ro dos 1 O CO Φ O Ο Ο 000 O O O Φ AND φ TO moi C ( and Pt [μ O- ’L_ O Φ i ί àmet Φ T3 O O Ο CN σ> Π. ~ a O Q. O st 1 O CO LO 1 st 1 O 0-1 1 O O 1 O O ω ü) CM O ω UJ CO CO O O O LO ο O O O £ 4— » O Q < < Q < CN st CO st x ~ CN H CL H

114

Table 7

10 cycles expenses 955 ° C- 120 treaty 2% Pt / 3.75% Cu / C 0.0476 0.0856 0.0569 0.0474 0.0458 0.025 0.022 0.0517 0.0191 0.0212 0.0176 0.4399 ω ο ο of g ο ο ω ZJ 75 ΙΟ ΙΟ · + - » (0 ο CD v ~ Hi HI cdJ X- O- 00 CO N CD CD • sp u- IO CO r- to co O CD O) t- LO θ '· co CO to st N * co 04 X ~ HI χ— CO to N- O O O O O O O O O O O st ο - ♦ - » CL O O O O O O O O O O O' O ω Ο ο Π5 ΟΙ ν- Ο) Τ “ CN ω ο ο 75 ΟΙ O 00 LO HI co 04 ^ t CO CO CD st CD Ό ο O- co r · * - O- CO to CN co LO st CO Ϊ3 O st r- to ”T st HI 04 IO X ~ 04 X " CO ο 0_ O O O O O O O O O O O St ο ΙΟ ΙΟ ζ O O O O O O O O O O O O V ” CD ΟΙ • <t w ο ο ο , 5% X® ο * · 04 CD CD CD CO St CD CO ΟΙ LO O IO B- to 04 CO CO HI HI V " IO ο LO <d St co co HI v— st χ— HI χ- st ο Ο 53 Z5 O O O O O O O O O O CO 00 CO 0. O O O O O O O O O O O O CD (Ο ο ο O ο Ο ΟΙ St CD l · - co CD St X " co st 't O r- to CD r ~ to to CN V " CD CO v st O- IO st st HI HI to X ~ HI HI CO ο 53 O O O O O O O O O_ O O St ο ΙΟ ΙΟ 0. IO O' O O O θ ' O' O O O O' CD O ο νο st CD 04 co “ ω ο ο ο ΟΙ O IO 00 co CO st X ~ HI 00 00 to ο ο O- IO H- CO IO • 't St co CO St oo co 53 O St O- LO St HI χ- to T— HI T— HI ο α. O O O O O O O O O O O St ο ΙΟ ΙΟ O O O O O" O O O O O O O σ> C0 CO ο CL ο L0 Ε ΙΟ φ 53 CD -— ' Ο. O to co co 00 CD St st r- x ~ CD <η Np l · - to CD co CD IO HI co st t— CD 0J O st 00 IO ω co CN CN to x- 04 CN st O O O O O O O O O O O st ο Ό ο ο 04 ο ο. ε .2 , 45% O O O O O' O O O O O O O Τ “ χ— CO ia C Φ X— HI IO co to CD co st st HI st co co co st co 00 V " to LO CT O to O co co st co HI LO HI HI 04 HI • Φ O t— O O O O O O O O O LO 2 co O O O O O O O O O O O O CT O O ·· - * ω O v_ O Q. O to O O u_ O AND Q. Φ to Ό O CT 7th • 4— » O • 4— » Φ co_ HI σ X " O O st co ’ 16.5 21.4 O r- 04 ume to t O st i LO CD 1 N- 1 CD 1 CD l x— 1 LO 1 co LO «TO st O_ O- CO T " HI v- CO co ^H χ- ~ O Q V St st LO CD ts- co ’ CD X ~ t— HI >

115

Figure 5C provides porosity data for each of the tested catalysts

Example 20

This example provides data from the analysis of the surface area (AS) and pore volume (VP) for a carbon support treated by contact with sucrose generally according to the method described below. The results are also provided for a nominal 2% PT / 3.45% Cu / C catalyst prepared using a carbon support treated by contact with sucrose, in general, as described below, together with the deposition of copper and platinum, in general, as described in example 12. The metal impregnated support was not subjected to high temperatures.

Carbon support (10 g) was added to a mixture including degassed H ₂ O (approximately 100 g), sucrose (approximately 3.8 g), 1M NaOH (approximately 6.15 g). To prepare the sucrose mixture, sucrose was first added to the water, followed by the addition of NaOH, which was followed by the addition of approximately 1.9 g of 37% by weight formaldehyde solution. After approximately 60 minutes at approximately 25 ° C, the mixture was acidified to a pH of approximately 4.8 by the addition of 2M HCI. The mixture was then stirred for about 45 minutes at approximately 25 ° C, then filtered to isolate the support and the support was dried for approximately 10 hours in a vacuum oven at a temperature of approximately 110 ° C in the presence of nitrogen. Approximately 11.5 g of treated support was recovered.

Both the catalyst and the treated support were analyzed by surface area and pore volume analysis generally as described by Wan et al., In the International Publication in WO 2006/031938. The results of the analysis of the surface area and pore volume are shown in tables 8 and 9, respectively. Figure 5D also provides pore volume results.

116

Table 8

description Average of carbon Precursor, 2% Pt / 3.45% Cu / C Adsorbed sucrose carbon Langmuir AS (m ² / g) 1499 957 954 AS by micro t-plot (m ² / g) 1193 727 726 AS of meso- macro-pores (m ² / g) 293,184 222,314 219,061 20-40 175,666 136,964 133,600 40-80 77,937 58.165 58.144 80-150 25,781 17.608 17,651 150-400 11.205 7,676 7,743 400-1000 2,159 1.625 1,672 1000-2000 0.396 0.276 0.251 2000-3000 0.04 0.000 0.000 AS total meso-macro-pores (m ² / g) 293,184 222,314 219,061

Table 9

Pore diameter (Â) Average carbon (3 lots) Precursor, 2% Pt / 3.45% Cu / C Adsorbed sucrose carbon <4.0 0.0541 0.0191 0.0193 4.0-4.6 0.1072 0.0478 0.0483 4.7-5.2 0.063 0.0381 0.0385 5.3-6.0 0.063 0.0475 0.0385 6.1-7.1 0.0465 0.0366 0.0464 7.2-8.0 0.0346 0.0243 0.0171 8.1-9.0 0.0235 0.0197 0.0222 9.1-13.4 0.0589 0.0443 0.0465 13.5-16.5 0.0216 0.0182 0.0149 16.6-21.4 0.0274 0.0207 0.0238 21.5-27.0 0.0254 0.018 0.0177 Total micro PV (cc / g) 0.5252 0.3333 0.3332

117

As shown in these results, the reductions in total surface area, surface area of micropores and surface of meso / macropores were approximately equivalent for the catalyst in which sucrose was present in the copper deposition bath, and for the treated carbon support by contact with sucrose individually. Based on these results, it is believed that a significant portion, if not almost all, of the reduction in surface area for the finished catalyst compared to the initial support is based on the presence of sucrose in the copper deposition bath.

Example 21

This example details the microscopy results for the following samples:

(1) Carbon support having a total Langmuir surface of approximately 1500 m ² / g (including micropores with a surface area of approximately 1200 m ² / g and meso- / macropore surface area of approximately 300 m ² / g);

(2) Carbon support of (1) containing a nominal copper content of approximately 3.45% by weight. Generally deposited according to Example 12;

(3) A nominal 2% Pt / 3.45% Cu / C catalyst, including the support (1) and is generally prepared as described in example 12, but before heating at elevated temperatures;

(4) the nominal 2% Pt / 3.45% Cu / C catalyst (3) after heating to temperatures of approximately 950 ° C.

Microscopy analysis was generally conducted as described in example 46.

Carbon Support

Figure 6 is a STEM micrograph of the surface of the carbon support.

Copper Impregnated Support

Figures 7 and 8 are STEM micrographs of the Cu impregnated support surface. These results indicate Cu regions with

118 irregular morphology and size deposited on the surface of the carbon support.

Support Impregnated with Pt / Cu (before Heat Treatment)

Figures 9-12 are micrographs of the support surface impregnated with Pt / Cu before treatment at elevated temperatures. These results indicate the regions of Cu deposited on the surface of the carbon support having Pt deposited in it, which generally maintained the morphology and irregular size of the regions deposited with Cu.

Figure 13 provides a micrograph of STEM for a portion of the impregnated support. The marked Spectral Image of the portion was subjected to in-line scan analysis, the results of which are shown in Figure 14. As shown, the in-line scan analysis indicates the presence of copper and platinum along the portion of the spectral image.

Pt / cu / c catalyst (after heating)

Figure 15 is a photomicrograph of STEM and figure 16 is a high resolution TEM photomicrograph (HRTEM) of a portion of the Pt / Cu / C catalyst after heating to elevated temperatures. These Figs indicate a change in the morphology of the Pt / Cu regions. These results indicate the formation of spherical particles of sizes ranging from approximately 1 nm to approximately 15 nm.

Figures 17 and 18 are Eds spectra for particles of varying sizes. As the particle size increases, the ratio of copper atoms to platinum increases, indicating a relatively constant amount of platinum between the particles. It is currently believed that the thickness of the platinum layer is relatively constant over a particle size range.

Pt / Cu / C Catalyst Used in 3 PMIDA Reaction Cycles

Figures 19-21 are photomicrographs of STEM for a portion of a catalyst used in 3 PMIDA reaction cycles under the conditions noted above. These results indicate the presence of stable particles, of variable sizes, including those in the

119 approximately 1-1.5 nm.

Figure 22 provides in-line scan data for the portion of the Spectral Image marked on the catalyst surface in Figure 21. Based on the detection of Cu throughout the entire spectral image, with the highest copper content in the center of the particle, while the platinum signal remained relatively flat, these results suggest the presence of an outer shell containing relatively thin platinum (that is, no more than 3 atoms in thickness). That is, since the in-line scan analysis used an X-ray beam of approximately 1 nm (10 Â) in size, this suggests the presence of a shell containing platinum having a thickness of no more than 3 platinum atoms (the atomic size of the platinum is 3A).

Pt / Cu / C Catalyst Used in 30 PMIDA Reaction Cycles

These results are for the catalysts tested for 30 reaction cycles. STEM photomicrographs of figures 23 and 24 indicate the presence of stable particles, of variable dimensions, including approximately 1-1.5 nm. Figure 25 provides in-line scanning data for the spectral image of the portion marked in Figure 24. These results also indicate a relatively thin layer of platinum as both copper and platinum signals began to be detected at the same point by X-ray beams having a size of approximately 1 nm, again indicating the presence of a platinum-containing shell less than 1 nm thick (ie less than 3 platinum atoms).

Figures 26 and 71 provide EDS spectra for particles approximately 2 nm and 9 nm in size. As shown, the percentage of copper atoms increased significantly with particle size, including the presence of a copper-rich nucleus.

Example 22

This example describes the results of microscopy analyzes generally conducted as described in example 46 for: (1) a nominal 2% Pt / 3.45% Cu / C catalyst precursor prepared as

120 described in example 9, and (2) a nominal 2% Pt / 3.45% Cu / C catalyst prepared from the precursor (1) (for example, by heating the precursor to a maximum temperature of approximately 950 ° C ).

Figures 28 and 29 are TEM and STEM images for the precursor (1). Figures 30-37 provide TEM images and the corresponding in-line scan data for portions of the precursor surface. As shown by in-line scans, platinum and copper were detected throughout the particle.

Figures 38 and 39 are TEM and STEM images for the catalyst (2). Figures 40 and 42 indicate the portion of the catalyst surface analyzed by in-line scans, the results of which are shown in figures 41 and 43, respectively. The results of in-line scanning indicate the presence of platinum in all particles.

Example 23

This example provides the particle size distribution for the nominal 2% Pt / 3.45% Cu / C catalyst prepared as described in example 9. Fifteen images of the type shown in figures 44 and 45 were used to determine the size of a total of 1177 particles. The measured particle size distribution is shown in figure 46. This example also provides analysis of particle size distribution for the catalyst after use in PMIDA oxidation for 4 reaction cycles, under the conditions described in example 7. Fourteen images of the type shown in figures 47 and 48 were used to determine the size of 1319 particles. The size distribution of the measured particles is shown in figure 49.

Example 24

This example provides X-ray diffraction results for a nominal 2% Pt / Cu / C 3.45% catalyst prepared as described in example 12.

Figures 50 and 51 provide diffraction results for a surface area of the catalyst having a diameter of approximately 1 pm, measured using electron diffraction in the selected area (SAED).

121

Based on the production of FCC (cubic centered faces) indices (that is, the results denoted 113, 022, 002, and 111) and primitive cubic indices (that is, the results denoted 300, 221, 310, and 210), SAED results indicate the presence of a CuPt alloy phase (probably Cu ₃ Pt). The results may also indicate the presence of a metallic copper phase.

Figures 52 and 53 provide nanodifraction results from a single particle on the support surface. The nanodifraction results are obtained by focusing an X-ray beam that has a diameter of approximately 50 nm in diameter, over a portion of the catalyst surface. Based on the generation of primitive cubic indices (ie 010, 100, and 01-1), these results also indicate the presence of a CuPt alloy phase (probably Cu ₃ Pt). The indices denoted 200 and 11-1 are believed to be evidence of the presence of a Cu phase, Pt phase, or additional evidence of a CuPt alloy phase. Figures 54 and 55 highlight the results of nanodifraction (the circulated portions) indicating the presence of a metallic copper phase.

The following examples 25-42 provide reaction test data for various catalysts prepared, in general, as described in examples 8-18. Various parameters (for example, metal charge, metal deposition temperature and heat treatment temperature) have been modified to determine the effect, if any, on the catalyst's performance. Unless specifically noted otherwise, the metal impregnated support was heated to a maximum temperature of approximately 955 ° C in the presence of a hydrogen (2%) / argon atmosphere. The catalysts were generally tested for oxidation of PMIDA under the conditions indicated in example 7. Example 25

Catalysts: (1) Pt 2.5% / Cu 10%; (2) Pt 2.5% / Cu 20%; (3) Pt 2.5% / Cu 7.5%; and (4) Pt 5% / Fe 0.1% / Co 0.4%. (nominal composition).

Figure 56 provides cycle time data for each of (1) - (4) for nine reaction cycles.

122

Figure 57 provides platinum leach data for (1) and (2) for each of the nine reaction cycles.

Example 26

Catalysts: (1) Pt 2.5% / Cu 7.5%; (2) Pt 2.5% / Cu 5%; (3) Pt 5 5% / Fe 0.1% / Co 0.4%; and (4) 720 ° C / Pt 2.5% / Cu 10%. (nominal composition).

Figure 58 provides cycle time data for each of (1) - (4) for nine reaction cycles.

Example 27

Catalysts: (1) Pt 2.5% / Cu 10% and (2) 720 ° C / Pt 2.5% / Cu 10%. 10 (nominal composition).

Each catalyst was tested for 10 reaction cycles.

Figure 59 provides cycle time data.

Figure 60 provides IDA generation data.

Figures 61 and 62 provide residual formaldehyde and formic acid concentration 15, respectively.

Table 10 provides a comparison of platinum leaching for the two catalysts. As shown, less platinum was leached from the prepared catalyst including heat treatment at 720 ° C.

Table 10_

Pt / Parts per Million (ppm) Cycle 2.5% Pt10% Cu 720 ° C-2.5% Pt10% Cu 1 0.103 <0.02 2 3 0.0715 <0.02 4 5 0.0539 <0.02 6 7 0.0514 <0.02 8 9 0.0507 0.0202 10

123

Example 28

Catalysts: (1) Pt 2.5% / Cu 7.5%; (2)

815 ° C / Pt 2.5% / Cu 7.5%; and (3) Pt 5% / Fe 0.1% / Co 0.4%. (nominal composition). Each catalyst was tested for the nine reaction cycles.

Figure 63 provides cycle time data for each of (1)

- (3).

Figures 64 and 65 provide the concentrations of formic acid and residual formaldehyde, respectively for each of (1) - (3).

Example 29

Catalysts: (1) 815 ° C / Pt 2.5% / Cu 7.5%; (2) 815 ° C / Pt2.5% / Cu 7.5%; and (3) Pt 5% / Fe 0.1% / Co 0.4%. (nominal composition). Each catalyst was tested for the nine reaction cycles.

Figure (66) provides cycle time data for each of (1) - (3).

Figures 67 and 68 provide concentration of formic acid and residual formaldehyde, respectively, for each of (1) - (3).

Example 30

Catalysts: (1) 815 ° C / Pt 2.5% / Cu 7.5%; (2)

815 ° C / 2.5% Pt / 5% Cu; (3) Pt 5% / Fe 0.1% / Co 0.4%; (4) 815 ° C / Pt2.5% / Cu 3%. (nominal composition). Each catalyst was tested for the ten reaction cycles.

Figure 69 provides the IDA generation results for each of (1) - (4).

Figures 70 and 71 provide the concentrations of formic acid and residual formaldehyde, respectively, for each of (1) - (4).

Example 31

Catalysts: (1) 815 ° C / Pt 2.5% / Cu 5%; (2) 715 ° C / Pt2.5% / 5% Cu; (3) 615 ° C / Pt 2.5% / Cu 5%; and (4) Pt 5% / Fe 0.1% / Co 0.4%. (nominal composition). Each catalyst was tested for the ten reaction cycles and several parameters were compiled for nine or each of the ten reaction cycles.

Figure 72 provides the cycle time results.

124

Figures 73 and 74 provide the concentrations of formic acid and residual formaldehyde, respectively.

Figure 75 provides the results of the platinum leaching.

Figure 76 provides the results of IDA generation.

Figure 77 provides the results of NMG generation.

Figure 78 provides the results of total CO ₂ generation.

Example 32

Catalysts: (1) 915 ° C / Pt 2% / Cu 4% (heated in an atmosphere containing hydrogen, ie reduced): (2) 910 ° C / Pt 2% / Cu 4% (heated in an inert atmosphere , that is, calcined); and (3) Pt 5% / Fe 0.1% / Co 0.4%. (nominal composition). Each catalyst was tested for the nine reaction cycles.

As shown in figure 79, the cycle time was similar for each of (1) - (3), but the cycle time for catalyst (3) was slightly higher for cycles 3 through 8.

Figure 80 provides the results of formaldehyde production.

Figure 81 provides the results of formic acid generation.

As shown in figure 82, the generation of IDA was substantially equivalent for each catalyst during cycles from 3 to

9.

The results shown in figure 83 indicate reduced NMG generation for each of the 2% Pt catalysts, compared to the 5% Pt catalysts.

Figure 84 provides the results of total CO ₂ generation.

Example 33

This example provides platinum leaching results for the following catalysts: (1) 815 ° C / 2.5% Pt / 5% Cu; (2) 815 ° C / Pt 2.5% / Cu 3%; (3) 910 ° C / PT 2% / Cu 4%; (4) 908 ° C / PT 2% / Cu 3.6%; and (5) 975 ° C / Pt2% / Cu3.6%. (nominal composition). The results are shown in figure 85.

Example 34

This example provides test results for

125 catalysts in which the copper deposition temperature varied by approximately 10 ° C (approximately 25 ° C and approximately 35 ° C) while the temperature of the heat treatment after platinum deposition was substantially similar.

Catalysts: (1) 970 ° C / Pt2% / Cu 3.45% / 35 ° C and (2) 965 ° C / PT 2% / Cu 3.45% / 25 ° C. (nominal composition).

As shown in figures 86 and 87, the generation of formaldehyde and formic acid was slightly lower for the catalyst prepared with the highest copper plating temperature.

The results shown in figure 88 indicate a higher initial IDA generation for the catalyst prepared with the highest copper plating temperature, but similar results for each catalyst starting with the third cycle.

As shown in figure 89, platinum leaching was lower for the catalyst prepared at the lowest copper plating temperature. Fig. 90 indicates reduced initial copper leaching for the catalyst prepared at the lowest copper plating temperature.

Example 35

This example provides results for the PMIDA oxidation test extended over 30 reaction cycles.

The catalysts tested included:

(1) Pt2% / Cu / C 3.45% nominal prepared as described in example 12;

(2) Pt 5% / Fe 0.1% / Co 0.4%;

(3) Pt 2% / Cu / C nominal 3.45% prepared as described in Eexample 16;

(4) PT 5% / 0.5% Fe catalyst.

As shown in figures 91-94, the cycle time, total CO ₂ generation, formaldehyde generation and formic acid generation were substantially similar for each of (1) - (4). The catalyst load was constant for each catalyst; thus, catalysts (1) and (3) provided similar results at reduced platinum loads compared to catalysts (2) and (4).

126

Fig. 95 provides Cu and Fe leach data for catalysts (1), (3), and (4).

Example 36

This example provides the results of the 5 PMIDA oxidation tests for catalysts prepared at different calcination temperatures and having different copper levels. Catalysts: (1) 908 ° C / Pt 2% / Cu 3.6%; (2) 975 ° C / Pt 2% / Cu 3.6%; (3) 910 ° C / Pt 2% / Cu 4%; and (4)

970 ° C / Pt 2% / 3.45 Cu%. (nominal composition)

Figure 96 shows the results of IDA generation.

Figures 97 and 98 indicate substantially similar results for the generation of formaldehyde and formic acid.

Example 37

This example provides reactor test data for 2% Pt / 4% Cu / C catalysts prepared, in general, as described in example 11. Each catalyst was tested for the 9 PMIDA reaction cycles.

A catalyst was prepared by heating the metal impregnated support to a maximum temperature of approximately 950 ° C in the presence of an inert argon atmosphere. A second catalyst was prepared by contacting the metal impregnated support at a maximum temperature of approximately 950 ° C in the presence of an atmosphere of hydrogen / argon (2% / 98%) (v / v).

Cycle time and CO ₂ generation data are provided for the two catalysts in table 11. Figure 99 shows the cycle time for each catalyst.

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Table 11

Cycle Calcined Calcined H ₂ -Reduced H ₂ -Reduced 1 2220 38.75 1867 50.92 2 2226 37.67 2077 42.33 3 2181 37.58 2109 39.42 4 2181 38 2155 37.08 5 2179 37.25 2095 40.42 6 2094 39.25 2136 37.42 7 2078 39.75 2089 39 8 2075 39 2067 38.5 9 2034 40.33 2060 37.42

Example 38

This example provides reactor test data for a 2% Pt / 4% Cu / C catalyst or a Pt metal impregnated support

2% / Cu / C 4% (precursor) prepared, in general, as described in the example

11.0 catalyst and metal impregnated support were tested in 4 PMIDA reaction cycles. The catalyst was prepared by contacting a support impregnated with metal at a maximum temperature of approximately 950 ° C in the presence of an atmosphere of hydrogen / argon (2% / 98%) (v / v).

The cycle time and CO ₂ generation data are provided for the catalyst and the metal impregnated support in table 12. Figure 100 shows the cycle time for each catalyst.

Table 12

Cycle Precursor Precursor Catalyst Catalyst 1 2003.4 36.92 1866.6 50.92 2 1912.5 39.17 2076.8 42.33 3 1841 41.58 2109.2 39.42

Example 39

This example provides a comparison of Pt catalysts

128

2% / Cu / C 4% prepared using different sources of platinum. Each catalyst was prepared, in general, as described in example 11, including heating a metal impregnated support to a maximum temperature of approximately 950 ° C. Platinum was deposited by displacement deposition on a copper impregnated support using platinum sources of: (1) K ₂ PtCI ₄ (ie Pt ⁺² ions) and (2) H ₂ PtCI ₆ . H ₂ O (ie Pt ⁺⁴ ions).

Table 13 provides the cycle time, CO ₂ generation data, and difference in activity (based on cycle time) for each catalyst in 9 reaction cycles. Figures 101 and 102 provide cycle time data and activity differences.

Table 13

Cycle K ₂ PtCI ₄ K ₂ PtCI ₄ H ₂ PtCI ₆ H ₂ PtCI ₆ delta t % Activity 1 1866.6 50.92 1640.8 58.5 7.58 0.87 2 2076.8 42.33 1879.8 50.58 8.25 0.84 3 2109.2 39.42 1989.6 46.42 7 0.85 4 2155.1 37.08 1980.4 45.33 8.25 0.82 5 2095.1 40.42 1982 44.08 3.66 0.92 6 2135.9 37.42 1994.7 44.25 6.83 0.85 7 2089 39 1954.2 45.75 6.75 0.85 8 2066.8 38.5 1973.4 44.75 6.25 0.86 9 2059.6 37.42 1962.1 45.08 7.66 0.83 Time CO ₂ Average of 0.846 Total CO ₂ Cycle Total Cycle Time excluding the 5th Cycle

Example 40

This example provides CO chemisorption data (i.e., platinum site density) for catalysts of varying levels of platinum prepared, in general, as described in examples 8, 11, 14, and 15. Table 14 provides the CO chemisorption (determined generally according to the method described in example 67) and Figure 103 provides a plot of platinum loading versus platinum site density. The

129 catalysts were tested on the oxidation of PMIDA for 10 reaction cycles before the CO chemisorption analysis.

Table 14_

Pt Charge Chimisection Cycle 2 Pt site density (pmol CO / g catalyst) 2 20.24 2.5 30.1 3 34.9 4 58

These results show a linear relationship between the site density and the platinum charge. Based on these results, it is currently believed that a significant portion of the platinum incorporated in the catalyst is present in the form of a relatively thin shell. In contrast, a non-linear relationship between charge and platinum site density was observed for conventional platinum-containing catalysts.

It is currently believed that this is due to the fact that a larger portion of the platinum is distributed through the metal particles. Thus, in addition to a certain level of platinum, the density load of the platinum site does not increase, since the platinum portion distributed throughout the particles does not contribute to the exposed platinum surface area.

Example 41

Catalysts containing nominal metal content of approximately Pt 2% and Cu 4% were prepared, in general, as described in examples 11 and 12. The metal deposition bath was maintained under a nitrogen atmosphere during copper deposition.

The results of the reaction tests comparing Pt / Cu catalysts to 5% Pt / 0.5% Fe catalysts are shown in figure 104. As shown, all catalysts provided comparable activity.

130

Example 42

These examples detail the reaction test of nominal 3% Pt / 6% Cu catalysts prepared as described in example 14 with various catalyst loads. One catalyst was tested with a catalyst load of approximately 0.25 g and another was tested at a load of approximately 0.17 g. The performance of each catalyst was compared with a 5% Pt / 0.5% Fe catalyst prepared generally as described in US patent no. 6,417,133 with a load of 0.25 g. The total platinum and catalyst loads are summarized in table 15. The total CO ₂ generation results and cycle time results are shown in figures 105 and 106, respectively. In comparison with Pt 5% / Fe 0.5% catalysts, these results indicate improved activity for Pt 3% catalyst with equivalent catalyst load and at least comparable activity with low catalyst load.

Consequently, the Pt 3% catalysts of the present invention, or other similar catalysts, can be used to provide an improvement in the activity of the catalyst, or a reduction in the capital of the working metal. Table 15

Load of Cat. Reduction Pt Charge Reduction in Load of PT Condition One 0.25 g 0% 0.0075 g 40% Condition Two 0.167 g 33% 0.005 g 60% Control 0.25 g 0% 0.0125 g 0%

III. Additional Modalities

Preparation of iminodiacetic disodium acid (DSIDA)

Example 43

This example describes the analysis and testing of: (1) a copper and carbon-supported palladium (CuPdC) catalyst of the type described in U.S. Patent No. 5,916,840, 5,689,000 and / or 5,627,125; and (2) a catalyst for

CuPdC prepared as described in US Patent No. 5,916,840, 5,689,000 and / or 5,627,125 which was treated by contact with a mixture containing 1,4-cyclohexane-dione and ethylene glycol as described in example 1 (mechanism 2 ).

131

The treated and untreated catalysts were analyzed to determine their Langmuir surface areas and to provide comparisons of the microporous and macropore surface areas before and after treatment.

Table 16

Sample Diona Diol % Of the micropores original % Of the macropore original Carbon A 1,4-disubstituted Ethylene glycol 22.6 75.8 Carbon A 1,3-disubstituted Ethylene glycol 58.4 84 Carbon B 1,4-disubstituted Ethylene glycol 55.6 78.7 Carbon B 1,3-disubstituted Ethylene glycol 32.2 39.8 Carbon C 1,4-disubstituted Ethylene glycol 17.9 76.8 Carbon C 1,3-disubstituted Ethylene glycol 45 75.6 Carbon C 1,4-disubstituted 1,2-Propanediol 14.4 67.5 Carbon C 1,3-disubstituted 1,2-Propanediol 56.1 80.7

As shown in table 16, the catalyst treatment provided a 75% reduction in the catalyst micropore surface area, by providing a reduction in the macropore surface area by less than 20% (ie, a preferential reduction in the surface area micropores approximately 4 times greater than the reduction in the surface area of the macropores).

Treated and untreated catalysts were also tested for the conversion of diethanolamine to iminodiacetic disodium acid. Mixtures including water, the catalyst (original or modified) (2% w), diethanolamine (1.8% w), sodium hydroxide (2.4% w), and iminodiacetic disodium acid (DSIDA) (12.5% p) were heated to temperatures ranging from 150-160 ° C over the course of 5 hours and under a pressure of approximately 930 kPa (135 psig). These conditions

132 were selected to determine the performance of modified and unmodified catalysts, with respect to oxalate and glycine formation. The results are shown in figure 107. The modified catalyst provided an approximately 8-10 fold reduction in oxalate formation and an approximately 4 fold reduction in glycine generation. These results suggest that the modified catalyst provided reduced exposed noble metal, which is considered to contribute to the formation of glycine and oxalate.

Example 44

This example details the testing of copper-supported catalysts containing copper and palladium (CuPdC) in the preparation of DSIDA by DEA dehydrogenation. The catalysts were prepared as described in US Patents ^Nos 5,916,840, 5,689,000 and / or 5,627,125 and generally tested under the conditions described herein. Two CuPdC catalysts were generally prepared according to the method described in one or more of these patents. Each catalyst was prepared to include Cu 24% w. A catalyst was prepared using an untreated carbon support; this resulted in a catalyst including Pd 3% w (ie Cu 24% / Pd / C 3%). The second catalyst was prepared using a carbon support treated by the present method, as described in example 1 by contact with 1,4-CHDM; this resulted in a catalyst including approximately 2.4% w / w Pd (ie 24% Cu / 2.4% w / c). Thus, it is believed that the use of the modified support resulted in a reduction in the deposition of palladium.

Each catalyst was tested on the conversion of DEA to DSIDA generally in accordance with the conditions set forth in U.S. Patent No. 5,916,840, 5,689,000, and / or 5,627,125. The results are shown in figure 108 and Table 17.

As shown in figure 108, starting with the second cycle, the cycle time was reduced for the catalyst including 2.4% Pd on treated carbon support. That is, the catalyst prepared using the carbon support treated providing an increase in the activity of

133 approximately 15-20% at a low noble metal content. Table 17

Cycle Cu 24% in Pd 2.4% / Modified MC-10 Cu 24% in Pd 3% / MC-10 mol% Glycine Acid Oxalic Hydroxyethyl Glycine Glycine Acid Oxalic Hydroxyethyl Glycine 1 1.08 0.49 0.46 1.69 0.73 0.56 2 0.9 0.38 0.46 1.28 0.45 0.42 3 0.88 0.35 0.49 1.22 0.44 0.43 4 0.9 0.34 0.58 1.3 0.43 0.4 5 0.9 0.34 1.01 1.25 0.42 0.42 6 0.94 0.34 0.87 1.31 0.44 0.41 7 0.96 0.34 0.89 1.3 0.43 0.39 8 0.97 0.34 0.76 1.35 0.43 0.36 9 1.01 0.34 0.71 1.35 0.43 0.38 10 1.01 0.35 0.61 1.38 0.43 0.36

As shown in table 17, use of the 2.4% Pd catalyst on the modified carbon support provided generation of oxalic acid and 5 reduced glycine compared to the 3% Pd catalyst on the unmodified carbon support (for example, example, an improvement in oxalic acid and glycine, selectivities of approximately 15% and 25%, respectively).

IV. Platinum-Iron

Example 45

This example details the preparation of a catalyst having a nominal platinum content of 2% by weight and a nominal iron content of 4% on an activated carbon support having a Langmuir surface area of approximately 1500 m ² / g. The following preparation was carried out under nitrogen protection.

Activated carbon (approximately 10,458 g) and degassed water (approximately 90 g) were mixed in a partitioned beaker under an atmosphere of nitrogen. FeCb. H ₂ O (2.007 g) was

134 dissolved in degassed water (40 g) and this solution was pumped into the split beaker over a period of one hour. The pH of the slurry in the partitioned beaker was maintained at 4 by the introduction of 2.5 N degassed NaOH, as needed. After addition of FeCI ₃ solution was completed, the pH of the slurry was raised to approximately 4.5 and the slurry was allowed to mix at room temperature for approximately 15 minutes. The slurry was then heated to a temperature of approximately 60 ° C over a period of approximately 48 minutes, during which time the pH of the slurry was maintained at approximately 4.5 by the addition of 2.5N NaOH.

The pH of the slurry was then increased to approximately 10.5 over a period of approximately 30 minutes at a temperature of approximately 60 ° C, and at a rate of 0.5 pH units for 5 minutes. After adjusting the pH, the slurry was allowed to mix for approximately 10 minutes.

Sodium borohydride (NaBH ₄ ) (approximately 0.686 g) was dissolved in degassed water (approximately 20 g); seven drops of 2.5N degassed NaOH were added to stabilize the NaBH ₄ solution, and the resulting NaBH ₄ solution was introduced into the dividing beaker at approximately 60 ° C over a period of 20 minutes. The slurry was then allowed to mix for an additional ten minutes at approximately 60 ° C. The slurry was then filtered and the moistened filtration mass was then resuspended in the divider beaker in a degassed mixture of deionized water (approximately 90 g). The pH of the resulting slurry was then lowered to approximately 5 by the introduction of degassed 2M HCl.

K ₂ PtCI ₄ (approximately 0.456 g) was dissolved in degassed water (approximately 20 g) and the resulting Pt solution was then added to the dividered beaker over a period of three minutes. The resulting slurry was then allowed to mix under ambient conditions (approximately 22 ° C) for approximately 60 minutes, and then heated to a final temperature of 65 ° C over

135 a period of 30 minutes and then allowed to mix at 60 ° C. The resulting slurry was then filtered and washed twice in contact with degassed water (approximately 100 g) at a temperature of approximately 65 ° C. The washed sample was then dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a small stream of nitrogen, to form a Pt / Fe catalyst precursor.

The catalyst precursor was then heated at elevated temperatures to approximately 900 ° C in the presence of a stream of hydrogen / argon (2% / 98%; v / v) for approximately 120 minutes.

The finished Pt 2% / 4% Fe catalyst was tested for PMIDA oxidation under the conditions set out in example 7. The Inductively Coupled Plasma (ICP) analysis was used to determine the catalyst's leached platinum and iron and resided in the mixture reacional. The ICP analysis was conducted using an Inductively Coupled VG EXCEIL PQ Mass Spectrometer (Icp-MS) (commercially available from Thermo Jarrell Ash Corp., Thermo Elemental, Franklin, ma). The results are set out in table 18. The results are shown in table 18.

Fig. 109 provides results of the XRD analysis (conducted as set out in example 69) for the finished catalyst (i.e., before the reactor test).

136

Table 18

ο 1600.6 40.00 36.5 0.034 5.563 0.039 2309 6635 <0.01 <0.1 σ> 1932.0 [39.83 36.5 O δ θ ' 5.392 0.040 1737 5716 ο θ ' V ο V oo 1947.9 40.00 36.7 1940.7 39.25 37.0 ο δ θ ' 5.393 0.045 1660 6220 <0.01 <0.1 co 1957.5 38.83 37.4 m 1935.5 40.25 I 36.7 0.010 5,400 ' 0.051 1838 6143 ο ο ~ V Τ “ θ ' V Μ ^- 1946.8 39.92 36.9 co 1966.5 00 O hello co I 38.8 0.010 5.378 0.065 nineteen ninety 6555 δ ο ” V 0.494 CM 1871.4 39.75 37.9 V " 1766.6 45.00 I 35.7 00 ο ο θ ' 5.293 0.099 2421 9699 <0.01 I 1,484 Cycle 'O CM O O ro + - » O H Final Point (min) Maximum CO ₂ concentration (%) PMIDA (% ρ) Glyphosate (% ρ) IDA (% ρ) ε ο. Q. Ο CM X ο HCOOH (ppm) ε ^- ο. α. Μ- »Ω_ Fe (ppm)

137

Example 46

This example details the preparation of a catalyst that has a nominal platinum content of 2% by weight and a nominal iron content of 4% by weight, on an activated carbon support with a Langmuir surface area of approximately 1500 m ² / g. The following preparation was carried out under nitrogen protection.

The activated carbon (approximately 10,455 g) and degassed water (approximately 90 g) were mixed in a beaker with partition under an atmosphere of nitrogen. Fe ₂ (SO ₄ ) ₃ .H ₂ O (2.990 g) was dissolved in degassed water (40 g) and this solution was pumped into the split beaker over a period of one hour. The pH of the slurry in the partitioned beaker was maintained at 4 by the introduction of 2.5N degassed NaOH, as needed.

The mixing of the slurry components in the divider beaker took place for a total of approximately 20 minutes at a pH of approximately 4. The pH of the slurry was then increased to 4.5 by the addition of NaOH. The slurry was then heated to a temperature of approximately 60 ° C over a period of 30 minutes. During heating, the pH was maintained at 4.5 by the introduction of 2.5N degassed NaOH (as needed). At this elevated temperature, the pH of the slurry was raised to approximately 6.5 over a period of 20 minutes, through pH increases at a rate of approximately 0.5 pH units for 5 minutes.

Sodium borohydride (NaBH ₄ ) (approximately 0.681 g) was dissolved in degassed water (approximately 20 g) and then pumped into the divider beaker at approximately 60 ° C over a period of 20 minutes. The slurry was then allowed to mix for an additional ten minutes at 60 ° C. The slurry was then left to cool to 45 ° C, and then filtered. The moistened mass was then resuspended in the beaker with divider in a degassed mixture of deionized water (90 g). The pH of the resulting slurry was then lowered to approximately 5 by the introduction of degassed 2M HCl.

138

Ο Κ ₂ ΡίΟΙ ₄ (approximately 0.460g) was dissolved in degassed water (approximately 20g) and the resulting Pt solution was then added to the split beaker over a period of five minutes. The resulting slurry was then allowed to mix under ambient conditions (approximately 22 ° C) for approximately 60 minutes and then heated to a final temperature of 65 ° C over a period of 30 minutes and then , allowed to mix at 65 ° C for an additional 10 minutes. The resulting slurry was then filtered and washed twice by contact with degassed water (approximately 100g) at a temperature of approximately 65 ° C. The washed sample was then dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a small stream of nitrogen, to form a Pt / Fe catalyst precursor.

The catalyst precursor was then heated to elevated temperatures of up to approximately 900 ° C in the presence of a hydrogen / argon stream (2% / 98%; v / v) for approximately 120 minutes.

Table 19 presents the results of the PMIDA reaction tests, platinum leaching data, iron leaching data for the finished Pt 2% / Fe 4% catalysts.

139

Table 19

Ο x— 1602.2 40.17 37.2 0.009 5,497 0.032 2983 5958 0.032 <0.05 CD 1864.9 40.83 36.7 0.007 5.393 0.032 2300 5623 -1 0.027 <0.05 CO 1891.4 39.50 37.8 H- 1956.3 37.67 | 39.0 0.007 5.349 0.038 2149 5843 0.025 0.077 CO 1943.9 37.50 39.6 IO 1944.0 37.75 I 38.8 0.006 5.382 0.040 2203 6021 | 0.027 0.222 1978.7 35.67 41.3 QC 1951.2 36.75 39.9 0.006 5.249 0.055 2212 5525 0.024 0.629 CM 1933.8 37.33 39.6 - 1912.0 38.17 40.5 ND 5.184 0.139 2586 5387 I 0.019 16,420 Cycle 'ç? O CM O O "5 O H Final Point (min) Maximum CO ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) AND Q. Cl O CM X O HCOOH (ppm) AND CL CL CL 'and CL Q. there ll

140

Example 47

This example presents the results of the X-ray diffraction analysis (XRD) for the catalyst prepared as described in example 46. The XRD analysis was conducted as described in example 69.

The results are shown in Figures 110 and 111. These results indicate the presence of Fe3Pt bimetallic alloy.

Example 48

This example details the preparation of a catalyst with a nominal Pt content of 2% by weight and a nominal iron content of 4% by weight on an activated carbon support having a Langmuir surface area of approximately 1500 m ² / g . The following preparation was carried out under nitrogen protection.

The activated carbon (approximately 10,455 g) and degassed water (approximately 90 g) were mixed in a dividered beaker under an atmosphere of nitrogen.

FeCb-6H ₂ O (approximately 2.009g) was dissolved in degassed water (40 g) and this solution was pumped into the dividered beaker over a period of one hour. The pH of the slurry in the partitioned beaker was maintained at 4 by the introduction of 2.5N degassed NaOH, as needed. After adding FeCI ₃ solution. 6H ₂ O for the beaker was completed, the pH of the slurry was raised to approximately 4.5 by the addition of NaOH and the suspension was allowed to mix under ambient conditions (approximately 22 ° C) for approximately 20 minutes.

The slurry was then heated to a temperature of approximately 60 ° C over a period of approximately 50 minutes. During heating, the pH was maintained at 4.5 with the addition of degassed 2.5N NaOH. At this elevated temperature, the pH of the slurry was raised to approximately 10.5 over a period of 30 minutes, through pH increases at a rate of approximately 0.5 pH units for 5 minutes.

Sodium borohydride (NaBH ₄ ) (approximately 0.69 g) was dissolved in degassed water (approximately 20 g); 7 drops of NaOH

141

2.5N was added to stabilize the NaBFU solution. The sodium borohydride solution was then pumped into the partitioned beaker at approximately 60 ° C over a period of 20 minutes. The slurry was then filtered and the wet filtration mass was then resuspended in the beaker with divider in a degassed mixture of deionized water (90 g). The pH of the resulting slurry was then lowered to approximately 5 by the introduction of degassed 2M HCl.

The IQPtCU (approximately 0.460 g) was dissolved in degassed water (approximately 20 g) and the resulting Pt solution was then added to the split beaker over a period of three minutes. The resulting slurry was then allowed to mix under ambient conditions (approximately 22 ° C) for approximately 60 minutes, and then heated to a final temperature of approximately 65 ° C.

The resulting slurry was then filtered and washed twice by contact with degassed water (approximately 100 g) at a temperature of approximately 65 ° C. The washed sample was then dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a small stream of nitrogen, to form a Pt / Fe catalyst precursor.

The catalyst precursor was then heated to elevated temperatures of up to approximately 900 ° C in the presence of a stream of hydrogen / argon (2% / 98%; v / v) for approximately 120 minutes.

Table 20 sets out the results of the PMIDA reaction tests, platinum leaching data, iron leaching data for the finished Pt 2% / Fe 4% catalyst.

142

Table 20

ο 1602.2 42.58 35.0 0.060 5.245 0.041 1831 6941 0.019 0.062 05 1875.6 42.00 i 35.4 0.009 5.298 0.042 1682 -1 6487 0.015 0.053 00 1862.4 42.25 35.3 l · - 1878.0 41.50 35.9 0.009 5.389 0.045 1706 6648 0.015 0.124 CD 1872.0 41.58 35.6 in 1866.1 41.50 35.7 0.009 i 5,441 0.046 1669 ι 6919 0.015 0.178 M 1857.1 41.67 35.7 00 1846.2 42.08 35.6 0.010 5.371 0.054 1857 7161 0.013 0.543 CM 1826.0 42.50 35.3 V 1738.2 46.75 34.4 0.007 5.339 0.083 2158 7454 O θ ' 3,114 Cycle 'O O, CM O O «5 + -> O H End point (min) Maximum C0 ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) Q. 'D. O CM ZL O HCOOH (ppm) Pt (ppm) Fe (ppm)

143

V ~ CM 1830.5 45.25 33.9 0.010 5.424 0.037 1853 6175 0.023 <0.05 20 1845.7 44.25 34.4 0 0 θ ' 5,477 0.036 2107 6582 0.024 <0.05 σ> 1854.1 44.25 34.1 0.010 5.371 0.037 2173 5805 0.024 <0.05 OO T " 1837.5 44.33 34.1 l · - 1872.9 43.83 34.4 0.010 5,382! 0.039 CM 6302 0.023 <0.05 co 1890.5 42.08 35.5 IO 1855.9 43.58 34.6 0.009 5.406 0.038 2067 6199 0.024 0.054 1868.5 42.67 35.0 CO 1878.2 42.25 35.5 0.010 5.405 0.041 2086 6287 0.024 <0.05 04 1868.2 42.33 35.9 - 1875.8 41.33 35.7 0.009 5.315 0.043 1898 6159 0.023 <0.05 Cycle O CM O O here * O H End point (min) Concentration maximum CO2 (%) PMIDA (% p) Glyphosate (% p) IDA (% p) Q. Q. O CM X 0 HCOOH (ppm) Pt (ppm) Fe (ppm)

144

Figure 111Α includes platinum leaching data for the catalysts of examples 46 and 48, compared to a Pt catalyst

5% / 0.5% Fe (reference) prepared as described by Wan et al., In Publication

International in WO 2006/031938.

Example 49

The following preparation was carried out under nitrogen protection.

The activated carbon (approximately 10,456 g) and degassed water (approximately 90 g) were placed in a dividered beaker and left to mix for 20 minutes. FeCI ₃ . 6H ₂ O (2.009 g) was dissolved in degassed water (approximately 40 g) and this solution was pumped into the beaker with partition over a period of 30 minutes while the pH of the slurry was maintained at 4 by the addition of NaOH 2.5N. After adding FeCI ₃ solution. 6H ₂ O, the pH was raised to 4.5 and the solution was allowed to mix for 10 minutes. The slurry was then heated to approximately 50 ° C over a period of 30 minutes, while the pH was maintained at pH 4.5. The slurry pH was then raised to 8 over a period of 15 minutes, and the solution was allowed to mix for approximately 10 minutes. Ethylene glycol (approximately 1.386 g) was then added to the slurry, and the solution was allowed to mix at approximately 60 ° C for approximately 20 minutes. After the mixing was complete, the slurry was allowed to cool to 30 ° C.

The pH of the solution was then lowered to 5 by the addition of degassed 0.5M HCl. K ₂ PtCI ₄ (0.460 g) was dissolved in degassed water (20 g). The Pt solution was then added to the split beaker over a period of three minutes. The slurry was then allowed to mix under ambient conditions (approximately 22 ° C) at room temperature for 30 minutes, and then heated to a temperature of 60 ° C over a period of 10 minutes.

The slurry was then filtered, and the wet filter cake was hot washed twice at 60 ° C with approximately 100 ml of degassed water. The resulting sample was then dried in a vacuum oven at 110 ° C for 12 hours with a small stream of nitrogen.

145

Example 50

The following preparation was carried out under nitrogen protection.

The activated carbon (10,456 g) and degassed water (approximately 90 g) were placed in a dividered beaker and allowed to mix for 20 minutes. FeCI ₃ . 6H ₂ (2.011 g) was dissolved in degassed water (approximately 40 g) and this solution was pumped into the beaker with partition over a period of 34 minutes while the pH of the slurry was maintained at 4 by the addition of NaOH 2 , 5N.

After the complete addition of FeCI3. 6H ₂ The solution, the pH was raised to 4.5, and allowed to mix for 10 minutes. The slurry was then heated to about 60 ° C over a period of 34 minutes, while the pH was maintained at 4.5. The slurry pH was then raised to 11 over a period of 30 minutes and then the solution was left to mix for 10 minutes. Ethylene glycol (1.385 g) was then added to the slurry, and allowed to mix at 60 ° C for approximately 10 minutes.

The pH of the solution was then lowered to 5 by the addition of degassed 1M HCl. OK ₂ PtCI ₄ (0.459 g) was dissolved in degassed water (20 g). The Pt solution was then added to the split beaker over a period of three minutes. The slurry was then allowed to mix under ambient conditions (approximately 22 ° C) for 30 minutes and then heated to a temperature of approximately 60 ° C over a period of 10 minutes.

The slurry was then filtered, and the wet filter cake was hot washed twice at 60 ° C with approximately 100 ml of degassed water. The resulting sample was then dried in a vacuum oven at 110 ° C for 12 hours with a small stream of nitrogen.

Four Pt 2% / 4% Fe catalysts were prepared from a precursor prepared as described, which was heated to elevated temperatures in the presence of a stream of hydrogen / argon (4% / 96%; v / v) for approximately 120 minutes. The maximum heating temperatures were:

(1) 900 ° C;

(2) 750 ° C;

146 (3) 650 ° C;

(4) 550 ° C.

Fig. 112 provides results of XRD analysis of the catalyst (1); these results indicate the presence of a Fe ₃ Pt phase.

Fig. 113 provides XRD analysis results for the catalyst (2);

these results indicate the presence of a Fe ₃ Pt phase.

Fig. 114 provides results of XRD analysis of the catalyst (3); these results indicate the presence of a Fe ₃ Pt phase.

Fig. 115 provides XRD analysis results for the catalyst (4); 10 these results indicate the presence of a Fe ₃ Pt phase.

The reaction test data, platinum leaching data, and iron leaching data for the 900 ° C / Pt 2% / 4% Fe catalyst are shown in table 21.

147

Table 21

03 1602.3 | - 42.90 34.4 0.104 5.539 0.032 2596 6488 0.017 0.409 Ι '' - I 1926.7 00 ο Μ ^- 36.1 0.006 5.376 0.034 2156 6358 0.013 CM CD M- O <Ω 1946.4 41.25 35.2 ΙΩ 1931.1 41.00 35.7 0.006 5,486 0.035 2072 6554 0.014 0.494 1930.6 40.75 35.5 00 1863.9 41.67 35.3 0.006 5.398 0.040 2513 6615 I 0.014 3.309 CM 1793.3 43.00 35.2 - 1751.9 44.08 36.2 0.003 5.243 0.079 3032 6300 I 0.011 24,050 Cycle 'θ' (Ν Ο Ο ro 4— » Ο Η End point (min) Maximum concentration of C0 ₂ (%) PMIDA (% p) Glyphosate (% p) IDA (% p) AND Ω. Ω. O CN X O HCOOH (ppm) AND Ω. Q. CL Fe (ppm)

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Table 22

σ> 1601.9 42.55 35.2 0.064 5.528 0.030 2550 6553 0.019 0.356 00 1913.3 (42.00 35.0 ο- 1921.1 41.50 35.6 O O O r- it 0.035 2010 6640 0.016 CO O- ’Φ O' <ο 1906.0 41.83 34.9 LO 1864.6 42.58 34.5 0.006 5,464 0.033 2105 6634 0.016 0.686 ’Φ 1901.3 I t 40.25 36.3 00 1854.8 41.42 35.7 0.009 5.357 0.037 2398 6628 0.015 3,516 04 1786.8 42.58 35.8 - 1812.9 39.92 39.2 ND 5.275 0.098 2901 6151 0.013 24,870 Cycle 'α CM Ο ο φ σ ro 4— » Ο Η Final point (min) Maximum concentration of C0 ₂ (%) PMIDA (% p) Glyphosate (% p) IDA (% p) eT CL Q. O CM ι O HCOOH (ppm) Pt (ppm) Fe (ppm)

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149

Table 23

O 1602.7 42.23 35.3 0.067 5.490 0.036 2754 6512 0.019 0.332 CD 1913.4 41.08 36.1 0.005 5.394 0.036 2395 I 6372 0.015 0.422 00 1901.6 41.50 35.5 r ^ · 1878.0 42.25 I 34.9 0.005 co T " ΙΩ 0.037 2358 6521 0.015 0.395 co 1947.6 O O 00 ~ co 39.7 IO 1957.4 39.08 i 37.7 0.006 5.394 0.040 2357 6461 0.015 0.493 1897.5 39.75 36.8 co 1908.8 39.33 37.2 0.005 5.373 0.045 2485 I 6634 0.016 2,754 CN 1849.5 40.67 36.7 T " 1782.0 41.42 38.7 ND 5.229 0.099 3042 ’ 6185 0.014 25,230 Cycle O The, CM O O Φ X co • 4— » O t- End point (min) Maximum concentration of C0 ₂ (%) PMIDA (% p) Glyphosate (% p) IDA (% p) And ~ X X O CM ΞΕ O HCOOH (ppm) X X CL Fe (ppm)

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150

Table 24

<35 1839.5 42.08 35.8 0.009 5.341 0.037 2425 7033 0.016 0.406 CO 1842.3 I 42.00 35.8 l · - 1887.9 140.17 37.3 0.007 5.339 0.041 2236 7100 0.016 0.315 CO 1891.8 ί 39.67 37.5 LO 1876.2 [40.25 36.7 900Ό 5.379 0.044 2018 7141 0.015 0.594 1881.2 39.08 I 38.0 CO 1885.9 38.58 38.6 0.007 5.376 0.049 2306 7076 0.015 2.972 CM 1842.8 39.58 38.1 - 1834.2 38.17 41.0 0.003 5.197 0.095 2670 6221 0.015 27,940 Cycle Total C0 ₂ (cc) Final Point (min) Maximum CO ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) HEY Q. The O CM X O HCOOH (ppm) Pt (ppm) Fe (ppm)

151

Example 51

The following preparation was carried out under nitrogen protection.

The activated carbon (approximately 10,456 g) and degassed water (approximately 90 g) were placed in a dividered beaker and mixed for approximately 20 minutes.

FeCh · 6H ₂ O (2.009 g) was dissolved in degassed water (approximately 40 g) and this solution was pumped into the beaker with a partition for a period of 30 minutes, while the pH of the slurry was kept at 4 by the addition of NaOH 2.5N. After the complete addition of the FeCl ₃ 6H ₂ O solution, the pH was increased to 4.5 and the slurry was mixed for 10 minutes. The slurry was then heated to 60 ° C over a period of 30 minutes, while the pH was maintained at pH 4.5, The pH of the slurry was then increased to 6.5 over a period of 10 minutes, and mixed for 10 minutes. Ethylene glycol (approximately 1.384 g) was then added to the slurry, and was mixed at approximately 60 ° C for approximately 10 minutes. The slurry was filtered, and the moist mass was then resuspended in degassed deionized water (90 g) and introduced into the beaker with a partition.

The pH of the solution was then reduced to 5 by the addition of degassed 1M HCl (0.841 g). K ₂ PtCI ₄ (0.459 g) was dissolved in degassed water (20 ml). The resulting Pt solution was then added to the partitioned beaker for a period of 3 minutes. The slurry was then mixed at room temperature (about 22 ° C) for 30 minutes and then heated to a temperature of 60 ° C for a period of 10 minutes.

The slurry was filtered, and the wet mass was hot washed twice at 60 ° C, with approximately 100 ml of degassed water. The resulting sample was dried in a vacuum oven at 110 ° C for 12 hours, with a small stream of nitrogen.

The catalyst precursor was then heated to elevated temperatures of up to approximately 755 ° C in the presence of a stream of hydrogen / argon (4% / 96%, v / v) for approximately 120 minutes.

Example 52

The next preparation was done under nitrogen protection.

152

Activated carbon (approximately 10,456 g) and degassed water (approximately 90 g) were placed in a dividered beaker and mixed for 20 minutes. FeCI ₃ -6H ₂ O (2.411 g) was dissolved in degassed water (approximately 41 g) and this solution was then pumped into the dividing beaker for a period of 30 minutes, while the pH of the slurry was maintained at 4 by adding 2.5N NaOH. After the complete addition of the FeCI ₃ -6H ₂ O solution, the pH was raised to 4.5, and the solution was mixed for 10 minutes. The slurry was then heated to 60 ° C for a period of 25 minutes, while the pH was maintained at pH 4.5, The pH of the slurry was then increased to 11 over a period of 30 minutes, and then mixed for 10 minutes.

Ethylene glycol (1.382 g) was then added to the slurry, and mixed at approximately 60 ° C for approximately 10 minutes. The slurry was filtered, and the wet mass was then resuspended in degassed deionized water (90 g) and introduced into the beaker with a partition.

The pH of the solution was then reduced to 5 by the addition of degassed 1M HCl (3.7 g). K ₂ PtCI ₄ (0.552 g) was dissolved in degassed water (20 g) and the Pt solution was then introduced into the beaker with a partition for a period of 3 minutes. The slurry was then mixed under ambient conditions (about 22 ° C) for 30 minutes and then heated to a temperature of 60 ° C for a period of 10 minutes.

The slurry was filtered, and the wet mass was hot washed twice at 60 ° C, with approximately 100 ml of degassed water. The sample was dried in a vacuum oven at 110 ° C for 12 hours, with a small stream of nitrogen.

The catalyst precursor was then heated to elevated temperatures of up to about 650 ° C in the presence of a stream of hydrogen / argon (4% / 96%; v / v) for approximately 120 minutes.

153

Table 24a

O T " 1600.2 37.67 37.8 0.106 5.538 0.039 2602 6283 0.022 0.541 σ> 2037.7 , 35.83 40.6 0.007 5,433 0.041 1659 5817 0.018 0.331 CO 2065.8 35.25 41.0 r- 2054.7 35.42 40.2 0.007 5.378 0.042 1897 5800 oo δ θ ' 0.372 CO 2058.7 35.58 40.0 IO 2055.9 35.50 39.5 0.005 5.410 00 M- O O" 1897 5858 I 0.018 0.577 Ν ' 2044.4 35.58 39.8 CO 2048.3 34.08 oo T j 0.005 5.341 0.057 2077 5891 0.018 2,713 CM 1977.4 34.92 41.3 - 1944.2 33.58 I 44.5 ND 5,121 I 0.155 2625 5320 0.019 30,170 Cycle ç? Õ3 O • 4— ¹ CN O o End point (min) Maximum CO ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) and Q. CL O CN X O HCOOH (ppm) CL Q. «* - · Dl Fe (ppm)

154

Example 53

The next preparation was done under nitrogen protection.

The activated carbon (10,456 g) and degassed water (approximately 90 g) were placed in a beaker with partition and were mixed for 20 minutes. FeCb · 6H ₂ O (2.009 g) was dissolved in degassed water (approximately 41 g) and the resulting solution was pumped into the dividered beaker for a period of 30 minutes, while the pH of the slurry was maintained at 4 by addition of 2.5N NaOH. After adding the FeCI ₃ -6H ₂ O solution, the pH was raised to 4.5, and it was mixed for 10 minutes. The slurry was then heated to approximately 50 ° C over a period of 32 minutes, while the pH was maintained at pH 4.5, The pH of the slurry was then increased to 8 over a period of 15 minutes, and then mixed for 10 minutes. Ethylene glycol (1.386 g) was then added to the slurry, and mixed at 60 ° C for ten minutes. The slurry was filtered, and the wet mass was then resuspended in degassed deionized water (90 g) and introduced into the beaker with a partition.

The pH of the solution was then reduced to 5 by the addition of degassed 0.5M HCI (2.17 g). K ₂ PtCI ₄ (0.460 g) was dissolved in degassed water (20 g) and the Pt solution was then introduced into the beaker with a partition for a period of 3 minutes. The slurry was then mixed at room temperature for 30 minutes and then heated to a temperature of 60 ° C for a period of 10 minutes. The slurry was filtered, and the wet mass washed hot twice at 60 ° C, with approximately 100ml of degassed water. The sample was dried in a vacuum oven at 110 ° C for 12 hours, with a small stream of nitrogen.

The catalyst precursor was then heated to elevated temperatures of up to approximately 550 ° C in the presence of a stream of hydrogen / argon (4% / 96%; v / v) for approximately 120 minutes.

Example 54

This example details the preparation of a catalyst with a nominal content of 2% wt platinum and a nominal content of 4% wt iron on an activated carbon support with a Langmuir surface area of approximately 1500

155 m ² / g. The next preparation was done under nitrogen protection.

The activated carbon (approximately 10,458 g) and degassed water (approximately 90 g) were mixed in a beaker with partition under a nitrogen atmosphere.

FeCI ₃ -6H ₂ O (approximately 2.028 g) was dissolved in degassed water (20 g) and this solution was pumped into the partitioned beaker for a period of approximately 25 minutes. The pH of the slurry inside the partitioned beaker was maintained at 4 by introducing degassed 2.5N NaOH, as needed. After adding the FeCI ₃ -6H ₂ O solution to the beaker, the pH of the slurry was raised to about 4.5 by adding NaOH and the slurry was mixed at room temperature (about 22 ° C ) for approximately 10 minutes.

The slurry was then heated to a temperature of approximately 60 ° C over a period of approximately 40 minutes. During heating, the pH was maintained at 4.5 with the addition of degassed 2.5N NaOH.

The pH of the slurry was then increased to approximately 7.5 over a period of approximately 15 minutes at a temperature of about 60 ° C, through increases in pH, at a rate of approximately 0.5 pH units per 5 minutes. The slurry was then mixed at a pH of approximately 7.5 for approximately 10 minutes, and then cooled to ambient conditions (about 22 ° C).

OK ₂ PtCI ₄ (approximately 0.460 g) was dissolved in degassed water (approximately 20 g) and the resulting Pt solution was then added to the beaker with a partition, for a period of approximately 20 minutes. The resulting slurry was mixed for about 30 minutes. The then mixed slurry was then cooled to about 60 ° C over a period of 45 minutes, and then mixed at 60 ° C for 15 minutes.

The resulting slurry was filtered and then dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a stream of nitrogen to form a Pt / Fe catalyst precursor.

The catalyst precursor was then heated to temperatures

156 elevated to about 950 ° C in the presence of a stream of hydrogen / argon (2% / 98%; v / v) for approximately 120 minutes.

Table 25 sets out the test results for the PMIDA reaction, the platinum leaching data, and the iron leaching data for the catalyst

Pt2% / Fe4% finished.

Table 25

Cycle 1 2 3 4 5 Total CO ₂ (cc) 2169.6 2196.5 2147.3 2122.5 2062.5 End point (min) 36.42 36.08 37.83 38.42 40.00 Maximum CO ₂ concentration (%) 40.5 39.7 37.8 37.5 36.4 PMIDA (% p) ND 0.008 0.008 Glyphosate (% p) 5.363 5.520 5,461 IDA (% p) 0.087 0.030 0.021 0.017 CH ₂ O (ppm) 1408 1143 1247 HCOOH (ppm) 5283 5733 5993 Pt (ppm) 0.122 0.153 0.155 Fe (ppm) 33,310 0.941 0.491

Example 55

This example provides microscopy results (performed in accordance with protocol B described in example 68) for the catalyst precursor prepared as described in example 54,

Figure 116 is a transmission and scanning electron microscopy (STEM) micrograph of a portion of the precursor surface, including points 1 and 2. Figures 117 and 118 are results of X-ray dispersive energy spectroscopy (EDX) analysis. ) for points 1 and 2, respectively. As shown, these portions of the precursor surface included iron well dispersed throughout, but not all iron had platinum deposited in it.

Figures 119 and 120 are STEM photomicrographs of a portion of the precursor surface indicating spatial distribution of the metal across the

157 carbon particle.

Figures 121 and 122 are a micrograph of STEM and a line scan of EELS for a portion of the precursor surface, 1, identified in the micrograph. Figures 123 and 124, and 125 and 126 are also pairs of analyzes of STEM micrographs and EELS line scan. These STEM and EELS results indicate the presence of iron in the entire carbon particle.

Example 56

This example details the preparation of a catalyst with a nominal content of 2 wt% platinum and a nominal content of 4 wt% iron on an activated carbon support with a Langmuir surface area of approximately 1500 m2 / g. The next preparation was done under nitrogen protection.

The activated carbon support (about 10,457 g) was introduced into a partitioned beaker under an atmosphere of nitrogen. FeCI ₃ -6H ₂ O (approximately 2.013 g) and sucrose (approximately 4.550 g) were dissolved in degassed water (approximately 85 g). 50% by weight of NaOH (approximately 5.225 g) was added and mixed with the sucrose solution - FeCI ₃ -6H ₂ O. The sucrose solution - FeCI ₃ -6H ₂ O was then poured into the partitioned beaker, and was mixed. The resulting slurry was heated to approximately 60 ° C for a period of approximately 10 minutes.

Ethylene glycol (approximately 1.263 g) was added to the partitioned beaker and mixed with the slurry for approximately ten minutes at approximately 60 ° C. The slurry was filtered, and the moist mass was resuspended in the beaker with a partition in degassed deionized water (approximately 90g). The pH of the resulting slurry was then reduced to approximately 7 by the addition of degassed 2M HCl.

OK ₂ PtCI ₄ (0.462 g) was dissolved in degassed water (approximately 20 g) to form a platinum solution that was pumped into the dividered beaker for a period of approximately 20 minutes. The resulting slurry was mixed at room temperature (about 22 ° C) for approximately 30 minutes and then heated to a temperature of approximately 60 ° C for a period of approximately

I

158 minutes. The final slurry was then filtered and the wet mass was dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a stream of nitrogen to form a Pt / Fe catalyst precursor.

The catalyst precursor was then heated to elevated temperatures of up to about 900 ° C in the presence of a stream of hydrogen / argon (2% / 98%; v / v) for approximately 120 minutes.

Table 26 establishes the test results of the PMIDA reaction, the platinum leaching data, and the iron leaching data for the Pt2% / Fe4% catalyst.

--μπ ·

159

Table 26

ο 1603.1 43.92 33.9 0.074 5.568 0.027 2915 6223 0.018 0.454 σ> 1871.1 43.67 34.3 0.011 5.423 0.028 2620 6018 0.015 0.457 00 1878.2 43.83 133.8 1891.9 43.08 34.6 0.009 5.488 0.028 2559 6123 0.014 0.751 co 1877.7 43.67 33.9 m 1926.6 41.58 35.6 0.010 5.348 I 0.032 2311 6124 0.016 0.694 Μ 1908.2 42.25 34.8 00 1881.3 41.92 35.4 0.009 5.397 0.038 2588 6290 0.014 3,238 <Ν 1812.5 43.50 34.7 - 1765.8 44.08 36.3 0.005 5.326 0.081 3191 6079 O O" V 55,230 Cycle Total C0 ₂ (cc) End point (min) Maximum CO ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) And ~ CL CL O CM I O HCOOH (ppm) AND CL Q. «+ - · CL Fe (ppm)

160

Example 57

This example details the results of the microscopy analyzes (carried out in accordance with protocol B described in example 68) for the final catalyst prepared as described in example 56,

Figures 127-132 include the results of microscopy for the catalyst after use in PMIDA oxidation tests, as described in example 56,

Figure 127 includes four high-resolution electronic photomicrographs (HREM) for various portions of the spent catalyst surface. These indicate the formation of graphite and iron oxide in the outer regions of the metal particles. Figure 128 includes three STEM micrographs, which indicate the presence of platinum regions with nanopores.

Fig. 129 is a micrograph of STEM showing several portions of the spent catalyst surface that were analyzed by EDX analysis. The results of the EDX analysis are shown in figure 130, which indicates the presence of a platinum-rich composition.

Figure 131 is also a micrograph of STEM and Figure 132 shows the results of the EDX analysis for the surface portions of the spent catalyst. These results indicate the presence of different metal compositions.

Figures 133-137 include the microscopy results for the finished catalyst prepared as described in example 56, but before testing the reaction.

Fig. 133 is a photomicrograph of STEM identifying a particle to be analyzed by in-line scanning analyzes of EELS, the results of which are shown in Fig. 134. As shown in Fig. 34, a partial iron oxide shell was detected.

Figure 135 is a HREM photomicrograph highlighting reticular Pt regions. As shown in Figure 35, the identified particles included no more than 4 platinum reticular zones. It is currently believed that each reticular zone corresponds to a layer of platinum atoms. That is, the identified particle included a platinum layer no more than about 4 platinum atoms in thickness.

161

Figures 136 and 137 are HREM photomicrographs identifying two layers of platinum atoms.

Figure 138 provides results of X-ray diffraction (XRD) analyzes, which indicate the formation of a Feo phase, 75Pto, 25,

Example 58

This example details the preparation of a catalyst precursor with a nominal Pt content of 2% p with a nominal iron content of 4% pm on an activated carbon support with a Langmuir surface area of approximately 1500 m ² / g. The next preparation was done under nitrogen protection.

Activated carbon support (about 10,456 g) was introduced into a partitioned beaker under an atmosphere of nitrogen. FeCI ₃ -6H ₂ O (approximately 2.011 g) and sucrose (approximately 4.511 g) were dissolved in degassed water (approximately 91.1 g). 50 wt% NaOH (approximately 5.214 g) was added and mixed with the FeCI ₃ -6H ₂ O - sucrose solution. The FeCI ₃ -6H ₂ O - sucrose solution was then poured into the partitioned beaker, and mixed with the activated carbon support. The resulting slurry was then heated to approximately 40 ° C for a period of approximately 10 minutes.

Ethylene glycol (approximately 1.309 g) was added to the partitioned beaker and mixed with the slurry for approximately 10 minutes at approximately 40 ° C. The slurry was filtered, and the moistened mass was resuspended in the beaker with a partition in degassed deionized water (90 g). The pH of the resulting slurry was adjusted / reduced to about 7 by the addition of degassed 2M HCl (1.52 g).

OK ₂ PtCI ₄ (approximately 0.461 g) was dissolved in degassed water (20 g) to form a platinum solution which was introduced into the dividered beaker for a period of 3 minutes. The resulting slurry was mixed at about 25 ° C for approximately 30 minutes and then heated to a temperature of approximately 60 ° C over a period of approximately 40 minutes.

The final slurry was filtered and the wet mass was washed twice by contact with degassed water (approximately 100 g) at a

162 temperature of about 60 ° C. The wet mass was dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a small stream of nitrogen to form a Pt / Fe catalyst precursor.

Example 59

This example details the preparation of a catalyst with a nominal platinum content of 2% for a nominal iron content of 4% on an activated carbon support with a Langmuir surface area of approximately 1500 m ² / g. The next preparation was done under nitrogen protection.

Activated carbon support (about 10,456 g) was introduced into a partitioned beaker under an atmosphere of nitrogen. FeCI ₃ -6H ₂ O (approximately 2.011 g) and sucrose (approximately 4.513 g) were dissolved in degassed water (approximately 91 g). 50 wt% NaOH (approximately 5.25 g) was added and mixed with the FeCI ₃ -6H ₂ O - sucrose solution. The FeCI ₃ -6H ₂ O - sucrose solution was then poured into the partitioned beaker, and mixed with the activated carbon support.

Ethylene glycol (about 1.31 g) was added to the partitioned beaker and the resulting slurry was heated to a temperature of approximately 30 ° C over a period of approximately 15 minutes. The slurry was filtered, and the wet mass was then resuspended in the beaker with a partition in deionized and degassed cold water (90 g) at a temperature of about 12 ° C. The pH of the resulting solution was reduced to approximately 7 by the addition of degassed 2M HCl (approximately 0.645 g) and 1M HCl (approximately 0.461 g).

OK ₂ PtCL (about 0.461 g) was dissolved in degassed cold water (about 20 g) at a temperature of about 12 ° C. The platinum solution was pumped into the split beaker for a period of approximately 20 minutes.

The final slurry was then filtered and the wet mass was dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a small stream of nitrogen to form a Pt / Fe catalyst precursor.

The catalyst precursor was then heated to temperatures

163 elevations of up to approximately 755 ° C in the presence of a hydrogen / argon stream (4% / 96%, v / v) for approximately 120 minutes.

Table 71 sets out the test results for the PMIDA reaction, the platinum leaching data, and the iron leaching data for the catalyst.

Pt2% / Fe4% finished.

164

Table 27

Ο V " 1600.2 48.50 I 31.7 0.057 5.516 0.029 2756 5842 0.022 0.375 σ> 1827.8 47.00 r- CN CO 900’0 5,508 0.029 2422 5850 0.017 0.423 oo 1825.1 47.42 32.0 l · - 1853.1 46.25 32.6 0.004 5,450 0.029 2434 5882 0.017 0.456 CO 1868.2 45.75 32.8 IO 1846.8 46.25 32.5 0.005 5.489 CO O O 2366 5987 0.019 0.552 1898.8 44.00 33.7 CO 1877.3 43.67 33.7 0.003 5,463 0.036 2914 6036 oo O θ ' 2,818 CN 1830.6 44.92 33.5 0.016 11,570 V " 1776.6 44.75 35.6 ND 5.278 0.079 3702 5549 0.016 36,130 Cycle Total CO ₂ (cc) End point (min) Maximum CO ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) and CL CL O Csl Έ O HCOOH (ppm) AND Q_ _Q. 0_ AND CL CL there LU

165

Example 60

Figures 139-148 include the results of microscopy (performed in accordance with protocol B described in example 68) for the finished catalyst prepared as described in example 59,

Fig. 139 is a micrograph of STEM identifying the particles analyzed by EELS line scan analysis, the results of which are shown in Fig. 140. As shown in Fig. 139, the Fe: Pt atomic ratio of the analyzed particle was 85.99 / 14.01, The results of the in-line scan of in figure 140 indicate the formation of an outer layer of iron oxide.

Fig. 141 is a micrograph of STEM indicating the particle that was analyzed by EDX in-line scan analysis, the results of which are shown in Fig. 142. In-line scan results indicate a relatively constant platinum signal, suggesting a very thin platinum shell. , that is, varying no more than about 25% during scanning across the particle (for example, from about 17.5 nm to about 46 nm along the scan line. As also shown in figure 142 , the variation in the magnitude of the iron signal during scanning across the particle is proportionally greater than the variation in the platinum signal during scanning across the particle (that is, on the order of at least about 1.5: 1) .

Figure 143 is a micrograph of STEM and Figures 144 and 145 correspond to EELS in-line scan analyzes and EDX in-line scan analyzes, respectively. The results of inline scanning of EELS indicate the presence of an iron oxide layer. The results of scanning in the EDX line indicate the presence of a thin platinum shell.

Figure 146 is a micrograph of STEM and figure 147 the corresponding EDX line scan analyzes. The results of in-line scanning indicate a relatively constant platinum signal, that is, varying by no more than about 25% during scanning across the entire particle from about 9 nm to about 35 nm along the scan line and a greater variation in the magnitude of the iron signal compared to the variation of the platinum signal (ie, on the order of about 1.5: 1).

Figure 148 provides the XRD results of the analyzes performed

166 as described in example 69, These results indicate the formation of a Feo, 75Feo, 25,

Figures 149-153 are microscopy results for the spent catalyst (ie, after being tested on PMIDA oxidation).

Fig. 149 is a micrograph of STEM showing several porous metal particles on the surface of the spent catalyst.

Figure 150 is a micrograph of STEM and Figure 151 shows the corresponding results of the EDX line scan analyzes. Figure 152 is a micrograph of STEM and Figure 153 the corresponding results of the EDX line scan analyzes. These results indicate a platinum-rich composition in all analyzed particles due to the leaching of iron from the core, that is, regions inside the particles to form particles rich in porous platinum.

Example 61

This example details the preparation of a catalyst precursor with a nominal Pt content of 2% p with a nominal iron content of 3.5% pm on an activated carbon support with a Langmuir surface area of approximately 1500 m ² / g. The next preparation was done under nitrogen protection.

The activated carbon support (about 10,457 g) was introduced into a partitioned beaker under an atmosphere of nitrogen. FeCI ₃ * 6H ₂ O (approximately 1.753 g) and sucrose (approximately 4.455 g) were dissolved in degassed water (approximately 90 g). 50 wt% NaOH (approximately 4.613 g) was added and mixed with the FeCl ₃ * 6H ₂ O - sucrose solution. The FeCI ₃ .6H ₂ O - sucrose solution was then poured into the partitioned beaker, and mixed with the activated carbon support. The slurry was then heated to a temperature of about 60 ° C for a period of 10 minutes.

Ethylene glycol (approximately 1,200 g) was added to the partitioned beaker and mixed with the slurry for approximately 10 minutes at approximately 60 ° C. The slurry was filtered, and the wet mass was then resuspended in degassed deionized water (90 g) and introduced into the beaker.

167 with partition. The pH of the resulting slurry was reduced to about 6 by the addition of degassed 1M HCI (3.6 g).

OK ₂ PtCl4 (approximately 0.452 g) was dissolved in degassed water (approximately 20 g) to form a platinum solution which was introduced into the dividered beaker for a period of approximately 3 minutes. The resulting slurry was mixed under ambient conditions (about 22 ° C) for approximately 15 minutes and then heated to a temperature of approximately 40 ° C for a period of approximately 12 minutes.

The final slurry was filtered and the wet mass was hot washed twice by contact with degassed water (approximately 100g) at a temperature of about 60 ° C. The resulting sample was dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a small stream of nitrogen.

The catalyst precursor was then heated to elevated temperatures of up to approximately 755 ° C in the presence of a stream of hydrogen / argon (4% / 96%, v / v) for approximately 120 minutes.

Figure 154 provides XRD analysis results for the finalized Pt2% / Fe3.5% catalyst, which indicates the formation of an Fe ₃ Pt phase.

Table 28 sets out the test results for the PMIDA reaction, the platinum leaching data, and the iron leaching data for the finished catalyst. Figure 155 provides the results of the XRD analysis for the catalysts after the reaction test (ie, the spent catalyst). These results indicate the formation of a Pt phase.

168

Table 28

ο 1602.0 42.75 34.7 0.143 5.430 0.036 2612 6465 0.022 0.362 σ> 1967.6 41.67 35.4 'Φ O O the ~ 5,446 0.036 2068 6313 -, 0.016 0.363 CO 1947.8 41.83 x— ΙΌ CO r- 1956.0 00 in θ ' 'Φ 36.2 0.004 5.343 0.038 2272 * 6391 | 0.016 0.477 CD 1956.8 40.75 35.7 1970.6 40.42 36.2 0.004 5.405 0.039 2341 6489 I 0.014 0.584 · <Φ 1928.1 40.17 36.9 CO 1913.6 39.83 36.9 0.003 IO O Φ ΙΌ 0.045 2624 6539 0.013 2.502 CM 1841.8 41.67 36.0 - 1785.7 43.83 35.4 ND 5.169 0.085 3172 I 6258 0.011 24,680 O O O Total CO ₂ (cc) End point (min) Maximum CO ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) Ω. ^ CL O CM X O HCOOH (ppm) and CL CL AND CL CL there LL

169

Example 61A

This example details the preparation of a catalyst with a nominal Pt content of 2% p with a nominal iron content of 4% pm on an activated carbon support with a Langmuir surface area of approximately 1500 m ² / g.

The next preparation was done under nitrogen protection.

Activated carbon (approximately 10,456 g) and degassed water (approximately 90 g) were mixed in a dividered beaker for 20 minutes.

FeCI ₃ * 6H ₂ O (approximately 2.009 g) was dissolved in degassed water (40 g) and this solution was pumped into the beaker with a partition for a period of 30 minutes, maintaining the slurry pH at 4 with NaOH 2, 5N, if necessary. After the addition of the FeCI ₃ «6H ₂ O solution to the beaker was completed, the pH of the slurry was raised to 4.5 and mixed for 10 minutes.

The slurry was then heated to approximately 60 ° C for a period of approximately 30 minutes. During heating, the pH was maintained at 4.5. The pH of the slurry was then increased to 11 over a period of 30 minutes, and then mixed for 10 minutes. Ethylene glycol (1,388

g) was then added to the slurry, and mixed at approximately 60 ° C for approximately 10 minutes. The slurry was filtered, and the moist mass was resuspended in the beaker with a partition in degassed deionized water (approximately 90 g).

The pH of the solution was then reduced to 7 by the addition of degassed 0.5M HCl. K ₂ PtCI ₄ (0.460 g) was dissolved in 20 ml of degassed water. The Pt solution was pumped into the beaker with a partition for a period of 30 minutes. The resulting slurry was mixed under ambient conditions (approx. 20 ° C) for approximately 30 minutes and then heated to a temperature of approximately 60 ° C for a period of 10 minutes.

The resulting slurry was filtered and washed twice by contact with degassed water (approximately 100 g) at a temperature of about 60 ° C. The sample was dried in a vacuum oven at approximately 110 ° C for 12 hours with a small stream of nitrogen to form a precursor of

170 Pt / Fe catalyst.

The catalyst precursor was then heated to elevated temperatures up to about 650 ° C in the presence of an atom of a hydrogen / argon stream (4% / 96%, v / v) for approximately 120 minutes.

V. platinum-cobalt

Example 62

This example details the preparation of a catalyst with a nominal platinum content of 2% for a nominal cobalt content of approximately 4% on an activated carbon support with a Langmuir surface area of approximately 1500 m ² / g. The next preparation was done under nitrogen protection.

CoCI ₂ (1.686 g) and sucrose (4.499 g) were dissolved in degassed water (89.4 ml) in a screw-topped container whose interior was passed nitrogen. To this mixture was added 50% w of sodium hydroxide (5.209 g), nitrogen was passed into the container, and the solution was then mixed for one minute.

Activated carbon support (10,458 g) was added to a 400 mL beaker and the CoCI ₂ solution was then poured into the partitioned beaker, nitrogen was passed into the beaker, and the components were mixed at room temperature for approximately 5 minutes. . The resulting solution was heated to approximately 60 ° C over a period of approximately 40 minutes. Ethylene glycol (approximately 1.272 g) was then added, and the resulting solution was mixed at approximately 60 ° C for approximately 20 minutes.

The solution was then filtered through a porous glass filter, the resulting wet mass was returned to the beaker with a partition. The pH of the solution was reduced to approximately 4.7 by adding HCl (2M).

OK ₂ PtCI ₄ (about 0.460g) was dissolved in degassed water (20 ml) and the platinum solution was added to the beaker with a dropwise partition over a period of approximately three minutes. The resulting solution was mixed at approximately 25 ° C for approximately 60 minutes. The solution was then heated to approximately 60 ° C for a period of

171 approximately 20 minutes. The resulting solution was filtered, and the filtrate was hot-washed twice with degassed water (120 ml) at approximately 60 ° C. The sample was dried in a vacuum oven at 110 ° C for 12 hours with a stream of nitrogen.

The catalyst precursor was then heated to elevated temperatures up to about 900 ° C in the presence of a hydrogen / argon stream (4% / 96%, v / v) for approximately 120 minutes.

Example 63

This example details the preparation of a catalyst precursor with a nominal platinum content of 2% w and a nominal cobalt content of approximately 4% w on an activated carbon support with a Langmuir surface area of approximately 1500 m2 / g. The next preparation was done under nitrogen protection.

The activated carbon (10,458 g) was placed in a divider beaker. CoCI ₂ -6H ₂ O (1.685 g) and sucrose (4.566 g) were mixed and dissolved with degassed water (89.2 ml). 5.154 g of 50% w / w sodium hydroxide was added to the cobalt solution and mixed. The resulting CoCI ₂ -6H ₂ solution was then poured into the carbon partitioned beaker, and mixed.

The resulting slurry was heated to approximately 60 ° C for a period of 20 minutes. Sodium borohydride (approximately 0.558 g) was dissolved in degassed water (20 ml), to which 2.5N degassed NaOH (0.329 g) was added. The sodium borohydride solution was added to the split beaker at approximately 60 ° C over a period of approximately 20 minutes, and then mixed for an additional 10 minutes. The slurry was filtered, and the wet mass was washed twice at approximately 60 ° C. The resulting wet mass was then resuspended in degassed deionized water (90 g).

The pH of the solution was reduced to approximately 5 by the addition of degassed 2M HCl. The K2PtCI4 (0.459 g) was dissolved in degassed water (20 ml). The Pt solution was then added to the partitioned beaker for a period of approximately 3 minutes. The slurry was mixed at about 25 ° C for approximately 40 minutes and then

172 heated to a temperature of approximately 40 ° C.

The resulting slurry was filtered, and the wet mass was washed twice with hot water (approximately 100 ml) in approximately

60 ° C. The resulting sample was dried in a vacuum oven in approximately

110 ° C for 12 hours, with a small stream of nitrogen.

SAW. Platinum - Tin

Example 64

The next preparation was done under nitrogen protection. Activated carbon (10,457 g) was placed in a beaker with partition and mixed with degassed water (100 ml).

SnCI ₄ -5H ₂ O (2.545 g) and K ₂ PtCI ₄ (0.463 g) were dissolved in degassed water (20 ml). The Sn / Pt solution was then pumped into the partitioned beaker over a period of approximately 23 minutes. The temperature and pH of the Sn / Pt solution was increased simultaneously to approximately 60 ° C and approximately 7, respectively, over a period of approximately 45 minutes. The solution was mixed for about 30 minutes.

NaBH ₄ (1.310 g) was dissolved in degassed water (10 ml) and this solution was added to the split beaker over a period of 20 minutes. The resulting slurry was mixed for about 20 minutes, filtered, and the wet mass was hot-washed twice with approximately 100 ml of degassed water at approximately 60 ° C. The resulting sample was dried in a vacuum oven at 110 ° C for 12 hours, with a small stream of nitrogen.

The catalyst precursor was then heated at elevated temperatures to about 545 ° C in the presence of a hydrogen / argon stream.

VII. Platinum - Copper

Example 65 _ (2% / 98%, v / v) for approximately 120 minutes.

The next preparation was done under nitrogen protection.

Preparation of PT 2% Cu 4% nominal activated carbon: The following has been added to a beaker with partition including approximately

173

10 g of activated carbon: 1.64 g of CuSO ₄ -5H ₂ O solution, 4.51 g of sucrose, 90 g of degassed deionized water, and 4.63 g of NaOH 50% w. The mixture was heated to approximately 40 ° C and stirred for approximately 10 minutes with a mechanical stirrer. To this slurry was added 1.71 g of 37% formaldehyde diluted to 17.1 g with degassed deionized water. The resulting slurry was heated to approximately 40 ° C with continuous stirring for approximately 30 minutes (or until the solution became colorless). Then, the slurry was filtered, washed once in the filter, and then resuspended in water at pH 2.02, by the addition of degassed 1M HCl. A solution of 0.454g of K ₂ PtCI ₄ in 10g of degassed water was then added to the slurry, along with continuous stirring for approximately 30 minutes at ambient conditions. Then, the slurry was heated to approximately 60 ° C and stirred for approximately another 30 minutes. This slurry was then filtered and washed with water and dried under vacuum at approximately 110 ° C under a small stream of nitrogen. A total of 11.720 g of dry material was recovered. During heat treatment at a maximum temperature of approximately 950 ° C in the presence of an argon / hydrogen atmosphere (2% / 98%) (v / v) for approximately 120 minutes, the sample lost 13.5% by weight.

Figures 155A and 155B include the microscopy results for the finished catalyst. Figures 155C - 155f include the results of microscopy for the catalyst after the PMIDA oxidation test.

Example 66

This example details the preparation of a catalyst with a nominal platinum content of 2% w and a nominal copper content of 3.75% w on an activated carbon support with a Langmuir surface area of approximately 1500 m2 / g. The next preparation was done under nitrogen protection.

The activated carbon support (about 10,457 g) was introduced into a partitioned beaker under an atmosphere of nitrogen. CuSO ₄ .5H ₂ O (approximately 1.540 g) and sucrose (approximately 4.225 g) were dissolved in degassed water (approximately 91 g). 50% NaOH p (approximately 4.370 g) was added and mixed with the solution of

174

CuSO4-5H2O - sucrose, and the resulting solution was poured into the beaker with a partition, and mixed with the activated carbon support at a temperature of approximately 29 ° C for approximately 20 minutes.

Formaldehyde (37%) (about 1.604 g) was added to the partitioned beaker and mixed with the slurry for approximately 84 minutes at approximately 29 ° C. The slurry was filtered, and the moistened mass was then resuspended in degassed deionized water (90 g) and introduced into the beaker. The pH of the resulting slurry was reduced to about 4 by the addition of degassed 1M HCI.

The IQPtCU (approximately 0.427 g) was dissolved in degassed water (approximately 20 g) to form a platinum solution that was introduced into the dividered beaker for a period of approximately 3 minutes. The resulting slurry was mixed under ambient conditions (about 22 ° C) for approximately 30 minutes and then heated to a temperature of approximately 60 ° C, and then mixed for approximately another 30 minutes.

The final slurry was filtered and the wet mass was washed twice at 60 ° C by contact with degassed water (approximately 100g). The resulting sample was dried in a vacuum oven at approximately 110 ° C for approximately 12 hours with a small stream of nitrogen.

The catalyst precursor was then heated at elevated temperatures to about 950 ° C in the presence of a stream of hydrogen / argon (2% / 98%, v / v) for approximately 120 minutes.

Table 29 sets out the results of the PMIDA reaction tests, the platinum leaching data, and the iron leaching data for the finished catalyst.

175

Table 29

ο 1601.5 45.07 33.9 0.217 5,443 00 O_ CO 2517 5802 0.068 0.247 CD 1920.4 [44.92 33.8 0.005 5,474 0.019 1876 5780 0.046 0.284 co 1918.9 44.42 ι 33.9 l · - 1995.9 41.58 36.9 0.005 5.511 0.019 2105 5567 0.039 0.387 co 1996.5 42.33 34.9 m 2010.9 42.33 34.6 0.006 5,492 0.018 1905 I 5234 Ί 0.033 0.553 M · 2037.5 42.17 33.9 co 2048.7 42.00 33.7 0.004 5.553 0.021 2057 4945 0.031 0.953 CM 2049.0 43.50 32.6 - 1916.9 49.00 29.8 0.007 co r » LO 0.051 2208 4743 0.023 16,930 Cycle Total CO ₂ (cc) End point (min) Maximum CO ₂ concentration (%) PMIDA (% p) Glyphosate (% p) IDA (% p) Q. α O CM ΞΕ O HCOOH (ppm) eT CL O. £ Fe (ppm)

176

VIII. Test protocols

Example 67: Protocol A

The following example details the CO chemisorption analysis used to determine the exposed metal surface areas of catalysts prepared as described here. The method described in this example is referred to in this specification and in the appended claims as Protocol A.

This protocol exposes a single sample of two sequential CO chemisorption cycles.

Cycle 1 measures initial noble metal exposed in a state of zero valence. The sample is vacuum degassed and treated with oxygen. Then, the residual non-adsorbed oxygen is removed and then the catalyst is exposed to CO. The volume of CO irreversibly absorbed is used to calculate the density of the starting noble metal site (for example, Pt °).

Cycle 2 measures the total exposed noble metal. Without disturbing the sample after cycle 1, it is again degassed under vacuum and then treated with a flow of hydrogen and again degassed. The sample is then treated with oxygen. Finally, residual non-adsorbed oxygen is removed and then the catalyst is exposed to CO again. The volume of CO irreversibly absorbed is used to calculate the density of the total starting noble metal site (for example, Pt °). See, for example, Webb et al. Analytical Methods in Fine Particle Technology, Micromerítics Instrument Corp., 1997, for a description of the chemisorption analysis. Sample preparation, including degassing, is described, for example, on pages 129-130,

Equipment:

Micromeritics ASAP ~ Static chemisorption instrument 2010 (Norcross, GA); Required gases: UHP hydrogen; carbon monoxide, helium UHP; oxygen (99.998%); quartz flow through the sample tube with the filling rod, two caps, two quartz wool plugs, analytical balance.

177

Preparation:

Insert the quartz wool plug freely into the bottom of the sample tube. Obtain the sample tube tare with the first wool plug. Preweight approximately 0.25 grams of sample, then add this on top of the first quartz wool plug. Accurately measure the weight of the initial sample. Insert a second plug of quartz wool over the sample and gently press down to maintain contact with the sample mass, then add the filling rod and insert two caps. Total weight measurement (before degassing): Transfer sample tube to degas instrument port, then vacuum at <10 pg Hg during heating under vacuum at 150 ° C for about 8-12 hours. Release the vacuum. Cool to room temperature and weigh again. Calculate weight loss and degassed final weight (use this weight in the calculations).

Cycle 1:

Hold the sample tube at the port of the static chemisorption instrument. Flow helium (approximately 85 cm ³ / minute) at room temperature and atmospheric pressure through the sample tube, then heat to 150 ° C to 5 ° C / minute. Keep at 150 ° C for 30 minutes. Cool to 30 ° C.

Empty sample tube to <10 gg Hg at 30 ° C. Keep at 30 ° C for 15 minutes. Close the sample tube for the vacuum pump and perform the leak test. Empty the test tube while heating to 70 ° C to 5 ° C / min. Keep for 20 minutes at 70 ° C.

Oxygen (approximately 75 cm3 / minute) flows through the sample tube at 70 ° C and atmospheric pressure for 50 minutes.

Empty sample tube at 70 ° C for 5 minutes.

Flow helium (approximately 85 cm3 / minute) through the sample tube at atmospheric pressure and increase to 80 ° C to 5 ° C / minute. Keep at 80 ° C for 15 minutes.

Empty sample tube at 80 ° C for 60 minutes and keep under vacuum at 80 ° C for 60 minutes. Cool sample tube to 30 ° C and

178 continue emptying at 30 ° C for 30 minutes. Close the sample tube for the vacuum pump and perform the leak test.

Empty sample tube at 30 ° C for 30 minutes and keep under vacuum at 30 ° C for 30 minutes.

For a first CO analysis, CO absorptions are measured under static chemisorption conditions at 30 ° C and initial collector pressures of 50, 100, 150, 200, 250, 300, 350 and 400 mm Hg (gauge) to determine the total amount of CO adsorbed (that is, both chemisorpt and physisorbent).

Pressurize the collector to the starting pressure (for example, 50 mm

Hg). Open the valve between the collector and the sample collection tube allowing the CO to contact the sample in the sample tube. Allow the pressure in the test tube to equilibrate. The reduction in pressure from the initial collector pressure to the equilibrium pressure in the sample tube indicates the volume of

CO absorbed by the sample.

Close the valve between the collector and the sample tube and pressurize the collector to the next initial pressure (for example, 100 mm Hg). Open the valve between the collector and the sample tube and allow the CO to contact the sample in the sample tube. Allow the pressure in the test tube to equilibrate to determine the volume of CO uptake by the sample. Perform for each initial collector pressure.

Empty sample tube at 30 ° C for 30 minutes.

For a second CO analysis, CO absorptions are measured under static chemisorption conditions of 30 ° C and initial collector pressures of 50, 100, 150, 200, 250, 300, 350 and 400 mm Hg (gauge), as described above for the first CO analysis to determine the total amount of CO

Cycle 2:

After the second CO analysis of cycle 1, helium (approximately 85 cm ³ / minute) flow at 30 ° C and atmospheric pressure through the sample tube, then heat to 150 ° C at 5 ° C / minute. Keep at 150 ° C for 30 minutes.

179

Cool to 30 ° C. Empty sample tube to <10 pg Hg a

30 ° C for 15 minutes. Keep at 30 ° C for 15 minutes.

Close the sample tube for the vacuum pump and perform the leak test.

Empty sample tube at 30 ° C for 20 minutes.

Hydrogen (about 150 cm ³ / minute) flows through the sample tube at atmospheric pressure during heating to 150 ° C to 10 ° C / min. Keep at 150 ° C for 15 minutes.

Empty sample tube at 150 ° C for 60 minutes. Cool sample tube to 70 ° C. Keep at 70 ° C for 15 minutes.

Oxygen (approximately 75 cm ³ / minute) flows through the sample tube at atmospheric pressure and 70 ° C for 50 minutes.

Empty sample tube at 70 ° C for 5 minutes.

Flow helium (approximately 85 cm ³ / minute) through the sample tube at atmospheric pressure and increase the temperature to 80 ° C to 5 ° C / minute. Keep at 80 ° C for 15 minutes. Empty sample tube at 80 ° C for 60 minutes. Keep under vacuum, at 80 ° C for 60 minutes.

Cool sample tube to 30 ° C and continue emptying to 30 ° C for 30 minutes. Close the sample tube for the vacuum pump and perform the leak test.

Empty the sample tube at 30 ° C for 30 minutes and keep for minutes.

For a first CO analysis, CO absorptions are measured under static chemisorption conditions at 30 ° C and initial collector pressures of 50, 100, 150, 200, 250, 300, 350 and 400 mm Hg (gauge) to determine the total amount of CO adsorbed (that is, both chemisorpt and physisorbent).

Pressurize the collector at the initial pressure (for example, 50 mm Hg). Open the valve between the collector and the sample tube and allowing the CO to contact the sample in the sample tube. Allow the pressure in the test tube to equilibrate. The reduction in pressure from the initial collector pressure to the equilibrium pressure in the sample tube indicates the volume of

180 absorption of CO by the sample.

Close the valve between the collector and the sample tube and pressurize the collector to the next initial pressure (for example, 100 mm Hg). Open the valve between the collector and the sample tube allowing the CO to come into contact with the sample in the sample tube. Allow the pressure in the test tube to equilibrate to determine the volume of CO uptake by the sample. Perform for each initial collector pressure.

Empty sample tube at 30 ° C for 30 minutes.

For a second CO analysis, CO absorptions are measured under static chemisorption conditions at 30 ° C and initial collector pressures of 50, 100, 150, 200, 250, 300, 350 and 400 mm Hg (gauge), as described above for the first co analysis to determine the total amount of CO

Calculations:

Plot the first and the second line of analysis in each cycle: volume of CO-phytorid and chemo-livid (first analysis) and volume of CO-phytorid (second analysis) (cm ³ / g in STP) versus target CO pressure (mm Hg). Plot the difference between the first and second lines of analysis at each target CO pressure. Extrapolate the difference line to its intersection with the Y-axis. In cycle 1, Pt ₀ total exposed (pmol CO / g) = Y-intersection of difference line / 22,414 X 1000, In cycle 2, Pt total exposed (pmol CO / g) = Y-intersection of difference line / 22,414 X 1000, Example 68 (Microscopy): Protocol B

This Example details microscopy analyzes of catalyst samples of the present invention.

High Resolution Electron Micrograph (HREM):

HREM for different catalyst samples were generated using a transmission electron microscope (TEM) with field emission gun (FEG) Jeol 2100 operated at an acceleration voltage of 200 keV. The samples were placed in the container as they were, without carbon interference (that is, the samples were not microtome and incorporated in a material with organic product, such as

181 an epoxide), and under ring conditions of identified reticular zones.

Atomic Layer Measurements:

Lattice spacing of catalyst particles identified by TEM was measured. These measurements were calibrated based on known spacing (3.84 A) of monocrystalline silicon (110), which was also analyzed using TEM-FEG (Jeol 2100) with the same magnification and acceleration voltage (200 KeV). The measurements were recorded and analyzed using the Digital Micrograph software. The number of platinum atomic layers for the analyzed particles was determined based on the number of repeated reticular zone rings, observed in the HREM micrograph.

Inline Scan Analysis:

In-line scanning analysis with dispersive energy X-ray spectroscopy (EDX), was conducted using TEM-FEG (Jeol 2100) operated in scanning transmission electron microscopy (STEM) mode. The probe size was 1 nm.

In-line scanning analysis with electron energy loss spectroscopy (EELS) was conducted using TEM-FEG (Jeol 2100) operated in (STEM) mode with a probe size of 0.5 nm. Example 69 (X-ray diffraction)

This example details the method used for X-Ray Diffraction (XRD) analysis of the results reported here. Powder samples (less than approximately 0.2 g) were compacted using a pellet press to form sample pellets for analysis. The sample pellet was placed in a plastic sample container for analysis on a Bruker D8 Discover Diffractometer.

CukGX radiation (DCunÇ ^ 1.5418 Á) was produced in a closed copper tube at 40 kV and 40 mA. Before the experiment, a corundum sample was used to adjust for any peak distortion.

The sample container was placed in the XYZ stage and analyzed in the locked coupled scan mode; the cannon and the detector angles were kept at the same value (ie, Θ-ι = Θ ₂ ). Diffraction data

182 X-rays (XRD) were collected using a position sensitive detector

LynxEye® (PSD), which is 10 ³ times more sensitive than regular XRD. For each sample, an XRD spectrum was collected within the 2Θ domain of 090 ° with a step size of 0.02 ° and a total collection time of approximately 3 hours.

Example 70 (Surface Area and Pore Volume Analysis)

Several metal impregnated supports and catalysts have generally been analyzed to determine surface area and pore volume data as reported here using a Micromeritics 2010 Micropore analyzer with a Torr transducer and a Micromeritics 2020 Accelerated Surface and Porosimetry System also with a transducer of a Torr. These analysis methods are described, for example, in Analytical Methods in fine Particle Technology, First Edition, 1997, Micromeritics Instrument Corp, Atlanta, Georgia (USA), and in Principies and Practice of Heterogeneous Catalysis, 1997, VCH Editors, Inc, from New York, NY (USA).

The present invention is not limited to the above modalities and can be modified differently. The description of the preferred embodiments above, including the examples, is intended only to inform others skilled in the art of the invention, its principles and practical applications, so that others skilled in the art can adapt and apply the invention in its numerous forms, as well as can be better adapted to the needs of a particular use.

With reference to the use of the word (s) comprise or understand or comprise in this entire specification (including the claims below), unless the context otherwise requires, these words are used, on the basis and clear understanding that they they are even interpreted, not exclusively, and applicants intend that each of these words be interpreted in order to explain this entire specification.

When introducing the elements of the present invention or of the preferred embodiment (s) thereof, articles one (s), one (s), the (s),

183 the aforementioned (s) are intended to say that there is one or more of the elements. The terms comprising, including and having are intended to be inclusive and mean that there may be additional elements in addition to the elements listed.

In view of the above, it is seen that the various objects of the invention are achieved and other favorable results are obtained.

Claims (20)

1. Oxidation catalyst, characterized by the fact that it comprises a support of carbon particles, a first metal selected from the group consisting of cobalt, copper, iron, and combinations of the same, and platinum, with the support on its surface, particles that include the first metal and platinum, where: the distribution of platinum within at least one of the cited particles, as typified by the EDX in-line scan analysis, produces a platinum signal that varies by no more than 25% in a region Scanning 10 which has a dimension of at least 70% of the largest dimension of at least one particle and wherein the particles containing the first metal and platinum on the surface of the carbon support comprise a core comprising a first metal and a shell at least partially around the core and comprising platinum, the casing having a 15 thickness not exceeding three platinum atoms. 2. Oxidation catalyst according to claim 1, characterized by the fact that the platinum signal varies by no more than 20% over the entire scanning region. Oxidation catalyst according to claim 1 or 20 2, characterized by the fact that the sign of the platinum varies in no more than 20% through a scanning region having a dimension that is at least 60% of the largest dimension of the at least one particle. 4. Oxidation catalyst according to any one of claims 1 to 3, characterized in that the platinum signal varies 25 in no more than 15% across a scanning region having a dimension that is at least 50% of the largest dimension of the at least one particle. Oxidation catalyst according to any one of claims 1 to 4, characterized in that the atomic ratio of the planin to the first metal of the at least one particle is less than 1: 1. 6. Oxidation catalyst according to any one of claims 1 to 5, characterized by the fact that at least one part Petition 870180000369, of 01/03/2018, p. 6/14 cell has a dimension greater than at least 6 nm. Oxidation catalyst according to any one of claims 1 to 6, characterized in that the at least one particle constitutes at least 1% of the metal particles on the surface of the carbon carrier. Oxidation catalyst according to any one of claims 1 to 7, characterized in that the distribution of the first metal from at least one metal particle, as typified by the EDX in-line scan analysis, produces a first metal signal , the reason for 10 maximum first metal signal for maximum platinum signal across the entire scan region being at least 1.5: 1. 9. Oxidation catalyst according to any one of claims 1 to 8, characterized by the fact that the EDX in-line scan analysis is performed using a transmission electron microscope15 are operated in the scanning transmission electron microscopy (STEM) mode. Oxidation catalyst according to any one of claims 1 to 9, characterized in that the particulate carbon support is a porous carbon support, the catalyst comprising 20 one or more regions of first metal on the surface of the carbon support and one or more regions of platinum on the surface of one or more regions of first metal, where the first metal has a greater electropositivity than the electropositivity of platinum, where the oxidation catalyst is prepared by a process that comprises contacting the carbon support 25 having one or more regions of first metal on its surface with a platinum deposition bath comprising platinum ions, thereby depositing the platinum by displacing the first metal from one or more of said regions, and the weight ratio of platinum for the first metal is at least 0.25: 1. 30 11. Oxidation catalyst, characterized by the fact that it comprises a particulate carbon support, a first metal selected from the group consisting of cobalt, copper, iron, and combinations of Petition 870180000369, of 01/03/2018, p. 7/14 same, and platinum, the support having on its surface metal particles comprising the first metal and platinum, in which: the metal particles comprise a core comprising the first metal and a shell, at least partially around the 5, and which comprises platinum, in which at least 70% of the platinum is present within the particle shell, the shell having a thickness not exceeding three platinum atoms. Oxidation catalyst according to any one of claims 1 to 11, characterized in that the first metal is ferrous. Oxidation catalyst according to any one of claims 1 to 12, characterized in that the first metal constitutes at least 1% by weight of the catalyst, or from 1% to 10% by weight of the catalyst. 14. Oxidation catalyst, characterized by the fact that it comprises a particulate carbon support, a first metal, and platinum, in which the first metal is copper, the support having on its metal surface particles comprising platinum and copper, in which the percentage of platinum atom on the surface of the particles is at least 40% and in 20 that the metal particles comprising platinum and copper on the surface of the carbon support comprise a core comprising copper and a shell at least partially surrounding the core and comprising platinum, the shell having a thickness of not more than three platinum atoms. 15. Oxidation catalyst according to any one of claims 1 to 14, characterized in that q platinum constitutes at least 1% by weight of the catalyst. 16. Oxidation catalyst according to any one of claims 1 to 14, characterized by the fact that the platinum constitutes 30 3% to 6% by weight of the catalyst. 17. Oxidation catalyst according to any one of claims 1 to 9 or 14, characterized by the fact that at least 10% Petition 870180000369, of 01/03/2018, p. 8/14 of the platinum is present within the metal particle casing. 18. Oxidation catalyst according to any of claims 1 to 9 or 11, characterized in that the percentage of platinum atom on the surface of the particles containing the first metal and the platinum on the surface of the carbon support is at least 2%. 19. Process for the oxidation of a substrate selected from the group consisting of iminodiacetic N- (phosphonomethyl) acid or a salt thereof, formaldehyde, and formic acid, characterized by the fact that it comprises: contacting the substrate with an oxidizing agent in the presence of the oxidation catalyst as defined in any one of claims 1 to 18. 20. Process according to claim 19, characterized by the fact that the substrate is iminodiacetic N- (phosphonomethyl) acid or a salt thereof. 21. Process according to claim 20, characterized in that said oxidation catalyst is effective for the oxidation of by-product of formaldehyde and / or formic acid produced in the oxidation of iminodiacetic N- (phosphonomethyl) acid or a salt thereof . Petition 870180000369, of 01/03/2018, p. 9/14 1/93