WO2021119899A1 - Process for producing a catalyst, catalyst and use thereof - Google Patents

Process for producing a catalyst, catalyst and use thereof Download PDF

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WO2021119899A1
WO2021119899A1 PCT/CN2019/125530 CN2019125530W WO2021119899A1 WO 2021119899 A1 WO2021119899 A1 WO 2021119899A1 CN 2019125530 W CN2019125530 W CN 2019125530W WO 2021119899 A1 WO2021119899 A1 WO 2021119899A1
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catalyst
nanoparticles
metal
octanol
process according
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PCT/CN2019/125530
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French (fr)
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Feng Niu
Vitaly ORDOMSKY
Zhen YAN
Bright KUSEMA
Andrei Khodakov
Stephane Streiff
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Rhodia Operations
Le Centre National De La Recherche Scientifique
Universite De Lille
Centrale Lille Institut
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Priority to PCT/CN2019/125530 priority Critical patent/WO2021119899A1/en
Publication of WO2021119899A1 publication Critical patent/WO2021119899A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/75—Cobalt
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74—Iron group metals
    • B01J23/755—Nickel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/391—Physical properties of the active metal ingredient
    • B01J35/393—Metal or metal oxide crystallite size
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B01J37/082—Decomposition and pyrolysis
    • B01J37/086—Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/16—Reducing
    • B01J37/18—Reducing with gases containing free hydrogen
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
    • C07C209/04—Preparation of compounds containing amino groups bound to a carbon skeleton by substitution of functional groups by amino groups
    • C07C209/14—Preparation of compounds containing amino groups bound to a carbon skeleton by substitution of functional groups by amino groups by substitution of hydroxy groups or of etherified or esterified hydroxy groups
    • C07C209/16—Preparation of compounds containing amino groups bound to a carbon skeleton by substitution of functional groups by amino groups by substitution of hydroxy groups or of etherified or esterified hydroxy groups with formation of amino groups bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/132—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group
    • C07C29/136—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH
    • C07C29/14—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of a —CHO group
    • C07C29/141—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of a —CHO group with hydrogen or hydrogen-containing gases
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/132—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group
    • C07C29/136—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH
    • C07C29/143—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of ketones
    • C07C29/145—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of an oxygen containing functional group of >C=O containing groups, e.g. —COOH of ketones with hydrogen or hydrogen-containing gases
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
    • C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
    • C07C45/37—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups
    • C07C45/38—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups being a primary hydroxyl group
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C45/00—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds
    • C07C45/27—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation
    • C07C45/32—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen
    • C07C45/37—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups
    • C07C45/39—Preparation of compounds having >C = O groups bound only to carbon or hydrogen atoms; Preparation of chelates of such compounds by oxidation with molecular oxygen of >C—O—functional groups to >C=O groups being a secondary hydroxyl group

Definitions

  • the present invention pertains to a process for producing a catalyst having a high dispersion of particles, as well as a catalyst having such a high dispersion and its use in chemical catalytic reactions.
  • the area of the invention is a catalyst comprising metal nanoparticles for heterogeneous catalysis.
  • the particle size of the active phase of a catalyst is one of the most important factors in determining the catalytic behavior of a heterogeneous catalyst in many systems, it has been widely investigated and metal nanoparticles (NP) have merged as a solution for increasing a reaction yield.
  • NP metal nanoparticles
  • dispersion of catalytic nanoparticles is a strategic parameter.
  • an increase of the activity for different reactions implementing highly dispersed catalytic nanoparticles is observed.
  • cobalt based catalysts are among the most popular and important materials for modern chemical industry, which have been widely used in the reactions of Fischer-Tropsch reaction, hydrogenation and dehydrogenation, oxidation and hydrogenolysis.
  • cobalt NP are prepared based on impregnation (or precipitation process) of Co salts precursors over silica, alumina or active carbon with subsequent calcination under air atmosphere followed by reduction in hydrogen to form active metallic cobalt.
  • the cobalt NP synthesized by this way often shows a broad size distribution (20- 200 nm) , which might have a negative effect on the long-term catalyst stability due to higher rate of carbon deposition on larger ones.
  • the present invention provides a solution for overcoming this drawback and relates to a process capable of increasing the dispersion of metal nanoparticles at least about 1.5, time, up to twice and even more, in comparison with the parent catalyst involved in this process.
  • the present invention provides a process for producing a catalyst comprising metal nanoparticles, said process comprising the following steps:
  • step (b) reducing the catalyst of step (a) ;
  • step (c) treating the reduced catalyst of step (b) with at least one alcohol
  • step (d) calcining the treated catalyst of step (c) to remove carbon species
  • This process is surprisingly able to produce a catalyst having a dispersion of the metal nanoparticles which is substantially higher than that of the metal nanoparticles of the catalyst of step (a) .
  • the dispersion of the metal particles comprised in the catalyst of the invented process reaches advantageously at least about 1.5 time, even about twice in some cases, that of the metal nanoparticles of the catalyst of step (a) .
  • the increase of the dispersion ranges from about 1.5 to about 2 times.
  • the above process is for producing a supported catalyst comprising nanoparticles, therefore the catalyst involved in step (a) is supported and the supported catalyst thus produced has a dispersion of the metal nanoparticles which is at least about 1.5 time that of the metal nanoparticles of said supported catalyst of step (a) .
  • the process of the invention enables preparation of a catalyst comprising nanoparticles having a size of 6 nm or less, preferably between 3-6 nm.
  • the invention provides a catalyst which may be obtainable in accordance the process of the invention, said catalyst having a dispersion of the metal nanoparticles which is at least about 1.5 time, even at least about 2 times, and preferably from about 1.5 to about 2 times that of the metal nanoparticles of catalyst of step (a) .
  • this catalyst is supported.
  • the catalyst of the invention comprises nanoparticles having a size of 6 nm or less, preferably between 3-6 nm.
  • this catalyst is supported and it comprises nanoparticles having a size of 6 nm or less, preferably between 3-6 nm.
  • the invention also concerns any use of this catalyst.
  • this catalyst may catalyze any reaction selected from amination, hydrogenation, dehydrogenation, hydrogenolysis and aerobic oxidation.
  • This catalyst may actually be involved in many reactions, and in particular in any reaction where the corresponding catalyst non-treated in accordance with the invention may be used.
  • the catalyst of the invention will evidence greater performances than the corresponding non-treated catalyst.
  • Nanoparticles are considered as particles having a diameter of no more than 100 nm, preferably no more than 50 nm, even no more than 20 nm. In accordance with the process of the invention, they may be as small as 10 nm in diameter, preferably 6 nm in diameter and may reach 3 nm in diameter, even less.
  • the diameter of nanoparticles may be measured by any technique well-known from the one skilled in the art. For example, it may be determined by using ex situ X-ray diffraction technique using oxide state of metal catalyst, or by using transmission electron microscopy (TEM) .
  • TEM transmission electron microscopy
  • a JEOL 2100 with Filament LaB6 having an acceleration voltage of 200 kV equipped with a camera Gatan 832 CCD may be used.
  • magnification factor may have a range of '10,000 ⁇ '600,000. For 50 nm: magnification factor was 40,000 ⁇ 50,000; for 20 nm: 60,000 ⁇ 120,000; for 10 nm : 250,000; for 5 nm : 400,000; for 2 nm: 500,000 ⁇ 600,000. Samples of 0.1 wt. %nanoparticles in methanol suspension are measured. The obtained results are analyzed using the DigitalMicrograph software. For each sample, two pictures are taken and a total of 100 nanoparticles are analyzed. From this size distribution, the average particle size of the nanoparticles is obtained. An appropriate software used to measure the size of the nanoparticles is ImageJ thereby approximating the particles to be spherical. After setting the scale, the maximum diameter of the particles is manually measured one by one to a total number of particles measured of 100.
  • Metal nanoparticles encompass nanoparticles comprising one metal or more, said metal (s) being in elemental form or a metal compound, or a mixture of a metal in elemental form and a metal compound.
  • metal NP essentially refers to NP comprising an active metal having a catalytic function; however, they may comprise one further metal or more that has no catalytic function but may promote it.
  • the dispersion of a catalyst is expressed by a ratio of NP S to NP T wherein NP S is the number of surface metal NP and NP T is the total number of NP. It may be measured by microscopy or chemisorption technique. These techniques are implemented in the examples.
  • STP Standard Temperature and Pressure
  • the metal of the nanoparticles is particularly selected from transition metals including group 12 metals of the periodic table, and lanthanides and actinides.
  • the transition metal is selected from the group consisting of nickel, cobalt, copper, chromium, platinum, palladium, rhodium, ruthenium, iridium, silver, gold, cerium, bismuth, rhenium and any mixture thereof; more preferably it is selected from the group consisting of nickel, cobalt, ruthenium and any mixture thereof, and most preferably it is cobalt, nickel and any mixture thereof.
  • the metal catalyst comprises one and only one transition metal in elemental form. In some embodiments, it comprises at least two transition metals in elemental form.
  • the metal catalyst may comprise one metal compound or more, particularly at least one transition metal compound. It is preferably selected from the group consisting of metal oxides, salts of metal and any combination thereof. Said salts could be chosen in the group consisting of halide, nitrate, nitrite, carbonate, bicarbonate, sulphate, sulphite, thiosulfate, phosphate, phosphite, hypophosphite, formate, acetate and propionate.
  • the metal catalyst comprises at least one transition metal in elemental form and its corresponding transition metal oxide.
  • the catalyst may be supported.
  • the supporting material may be those well-known to the person skilled in the art, which is usually selected from the group consisting of zeolites, Kieselguhr, silica, alumina, silica-alumina, clay, titania, zirconia, magnesia, calcia, lanthanum oxide, niobium oxide, carbon and any combination thereof. It is preferably selected from the group consisting of alumina, carbon and zeolites and more preferably, it is alumina or carbon and most preferably alumina, for example gamma-alumina.
  • the metal loading of the supported catalyst may be in a range of 1 to 30 wt. %, preferably 5 to 20 wt. %, mostly preferably 5 to 15 wt. %.
  • steps (a) to (d) of the process are outlined. It should be understood that they involve techniques that are well-known from the one skilled in the art. Thus, the present invention is not restricted to the use of the techniques described below, but it is considered that they are preferred, in particular to produce a catalyst on an industrial scale.
  • Step (a) regarding the preparation of a catalyst comprising metal nanoparticles a traditional impregnation or co-precipitation may be performed with subsequent calcination of the catalyst. Naturally, any other appropriate technique may be carried out in this step.
  • Step (b) is performed with a reducing gas which may be selected from hydrogen, carbon monoxide and mixtures thereof.
  • a reducing gas which may be selected from hydrogen, carbon monoxide and mixtures thereof. This reduction is carried out in the preferred following conditions: at a temperature of 200°C to 500°C, preferably 200°C to 450°C and/or for a period of 1 to 20 hours, preferably 3 to 15 hours. Appropriate conditions may result from any combination of these recommendations.
  • the supported metal catalyst nanoparticles are treated with at least one alcohol; this alcohol is advantageously selected from (C1-C16) -aliphatic monoalcohols and any mixture thereof.
  • the alcohol is selected from propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol and any mixture thereof, more preferably 1-butanol, 1-hexanol, 1-octanol and any mixture thereof.
  • the nanoparticles are treated with said alcohol being in liquid form or in gas form.
  • Step (c) is performed by contacting catalyst of step (b) with an alcohol in the preferred following conditions: at a temperature from 150 to 400°C, preferably 150 to 300°C, mostly preferably 200 to 300°C and/or for 0.1 to 8 hours, preferably 0.2 to 7 hours, most preferably 0.25 to 3 hours; appropriate conditions may result from any combination of these recommendations.
  • Step (d) consists in calcining treated catalyst of step (c) ; as previously mentioned, the implementation of this step unexpectedly results in dispersing catalytic nanoparticles.
  • This step may be conducted at a temperature from 200 to 500°C, preferably 300 to 500°C, mostly preferably 300 to 400°C and/or for 1 to 5 hours, preferably 2 to 4 hours, most preferably 2 to 3 hours; appropriate conditions that the one skilled in the art is able to determine, may result from any combination of these recommendations.
  • said supported catalyst is generally recovered. It may then be involved in any appropriate reaction.
  • a further reduction step is conducted before the supported catalyst is recovered, preferably after step (d) .
  • This step advantageously allows the activation of the prepared catalyst.
  • This reduction step may be carried out in the same conditions as step (b) .
  • this step may be performed with a reducing gas which may be selected from hydrogen, carbon monoxide and mixtures thereof.
  • This reduction is carried out in the preferred following conditions: at a temperature of 200°C to 500°C, preferably 200°C to 450°C and/or for a period of 1 to 20 hours, preferably 3 to 15 hours. Appropriate conditions may result from any combination of these recommendations.
  • the invention also provides a catalyst comprising metal nanoparticles having a high dispersion in comparison with the non-treated catalyst. As previously mentioned, it may supported. It comprises nanoparticles that have a size of 6 nm or less, such a size of 3-6 nm.
  • the metal nanoparticles may satisfy any feature previously mentioned in particular regarding the metal (s) , and the catalyst may be supported in any way as described above.
  • a catalyst is obtainable in accordance with a process as detailed above.
  • One preferred catalyst is a Co-catalyst or a Ni-catalyst, or any catalyst comprising a mixture of Co and Ni.
  • a catalyst in accordance with the invention is part of the invention. It may be used for catalyzing a reaction preferably selected from amination, hydrogenation, dehydrogenation, hydrogenolysis and aerobic oxidation.
  • Figure 1 represents the catalytic performance of a catalyst of the invention (3 vertical bars on the right) in comparison with a catalyst which is not encompasses within the invention (3 vertical bars on the left) , in three chemical reactions.
  • Figure 2 represents the catalytic stability of a catalyst of the invention in amination of 1-octanol, said stability being evaluated by measuring the conversion rate and selectivity.
  • Example 1 Preparation of a Co-catalyst involving a process in accordance with the present invention
  • the initial Co/Al 2 O 3 (10 wt%Co) catalyst was prepared by incipient wetness impregnation (IWI) of ⁇ -Al 2 O 3 using an aqueous solution of cobalt nitrate hexahydrate [Co (NO 3 ) 2 ⁇ 6H 2 O] .
  • the impregnated sample was placed for 10 h followed by drying under air at 80°C overnight and calcined under an air flow [ ⁇ 10 mL (STP) /min] with a heating ramp of 2°C/min from room temperature to 500°C for 4 h to get the oxidized catalyst.
  • the oxidized Co/Al 2 O 3 was reduced at 400°C for 2 h.
  • the reduced catalyst was transferred to 30 mL autoclave mixed with 1 g 1-octanol followed by charging 10 bar N 2 .
  • the catalyst was treated at 250°C for 2 h and then washed by ethanol and acetone for several times followed by drying at 80°C under vacuum for overnight.
  • the catalyst was denoted as “Co-Oct/Al 2 O 3 ” .
  • the catalyst “Co-Oct/Al 2 O 3 ” was calcined again at 400°C for 2 h.
  • step (d) The catalyst of step (d) is recovered and analyzed. It is labeled as Co-Oct-Cal/Al 2 O 3 .
  • the scans were recorded in the 2 ⁇ range between 10° and 80° using a step size of 0.02° and a step time of 5 s.
  • the catalysts for measurement were all in oxide state.
  • Thermogravimetric analysis was carried out under air flow [10 mL (STP) /min] in the temperature range of 40-800°C using a heating rate of 5°C/min on a Mettler Toledo SMP/PF7458/MET/600W instrument.
  • the HAADF-STEM analysis was performed using a Cs-corrected JEOL JEM-2100F microscope operated at 200 keV.
  • H 2 temperature-programmed reduction was performed by Micromeritics AutoChem II 2920 V30.2 apparatus equipped with a thermal conductivity detector (TCD) using 50 mg sample.
  • TCD thermal conductivity detector
  • the thermal profiles were measured from room temperature to 800°C with a temperature ramp of 5°C/min under a 5 v/v%H 2 /Ar flow [10 mL (STP) /min] .
  • CO chemisorption measurements were operated on the same instrument. 50 mg of the sample was first reduced under a 5 v/v%H 2 /Ar flow [10 mL (STP) /min] for 2 h. After cooling down to room temperature, the activated sample was treated by calibrated pulse of CO-He (5 vol. %CO) till full saturation. The dispersion of cobalt was calculated by division of integrated adsorbed atoms of CO by total amount of cobalt atoms.
  • XPS ex situ X-ray photoelectron spectrometry
  • the average particle size of Co 3 O 4 is calculated by Scherrer equation using X-ray line broadening method.
  • the calculated size for Co/Al 2 O 3 and Co-Oct-Cal/Al 2 O 3 are 4.1 nm and 19.6 nm, respectively.
  • the catalyst Co-Oct-Cal/Al 2 O 3 shows highly Co 3 O 4 dispersion of ⁇ 4 nm small NP; the size of individual cobalt NP is consistent with the one calculated from XRD results.
  • the Co metal dispersion and surface area were evaluated using CO adsorption in a pulse mode.
  • the metal dispersion of Co-Oct-Cal/Al 2 O 3 (2.1%) is nearly two times higher than that of the fresh Co/Al 2 O 3 catalyst (1.14%) .
  • the low dispersion (0.41%) of Co-Oct/Al 2 O 3 is caused by the surface carbon deposition after 1-octanol pretreatment, which is consistent with the H 2 -TPR results.
  • the reactor was charged with 0.84 g of 1-octanol and 25 mg catalyst followed by charging NH 3 (0.5 g) and H 2 (3 bar) into the reactor. Finally, the reactor was placed on a hot plate equipped with a magnetic stirrer at 180°C for 2_5 h.
  • tricosan-12-one For hydrogenation reaction of tricosan-12-one, the conditions were as follows: tricosan-12-one 0.1 g together with 5 ml ethanol and 10 mg catalyst under H 2 20 bar. The reaction was performed at 120°C for 10-45 min.
  • the reactor was cooled downed to room temperature, and the mixture was filtered and analyzed on an Agilent 7890 GC quipped with a HP-5 capillary column using biphenyl as the internal standard.
  • the stability of the pretreated catalyst was evaluated using amination of 1-octanol. For the typical cycle experiment, after each amination test, the catalyst was washed with ethanol and separated by centrifugation for several times and dried at 80°C for 10 h followed by activation in H 2 at 400°C for 2 h for further test.
  • Catalytic performance of Co/Al 2 O 3 and Co-Oct-Cal/Al 2 O 3 in amination of 1-octanol, hydrogenation of tricosan-12-one and aerobic oxidation of benzyl alcohol reactions are evaluated by activity normalized by amount of metal.
  • the results are shown in Figure 1 wherein for each catalyst the first vertical bar corresponds to the amination reaction, the second vertical bar corresponds to the hydrogenation reaction, the third vertical bar corresponds to the oxidation reaction.
  • the catalytic results show a significant increase of activity of the catalyst of the invention for amination, hydrogenation and oxidation reactions.
  • Example 4 Preparation of a Ni-catalyst involving a process in accordance with the present invention
  • the initial Ni/Al 2 O 3 (10 wt%Ni) catalyst was prepared by incipient wetness impregnation (IWI) of ⁇ -Al 2 O 3 using an aqueous solutions of nickel (II) nitrate hexahydrate [Ni (NO 3 ) 2 .6H 2 O] .
  • the impregnated sample was placed for 10 h followed by drying under vacuum at 80°C overnight and calcined under an air at 500°C for 4 h to get the oxidized catalyst.
  • step (a) The oxidized Ni/Al 2 O 3 of step (a) was reduced at 400°C for 2 h.
  • step (b) The reduced catalyst of step (b) is treated by 1-octanol at 250°C for 2 h and then washed by ethanol and acetone for several times.
  • washed catalyst was calcined again at 400°C for 2 h to remove the carbons.
  • the resulting catalyst was recovered and analyzed; it is labeled as Ni-Oct-Cal/Al 2 O 3 .
  • This catalyst was analyzed using the same techniques as those described in Example 2. They are reported in Table 2 below:
  • Ni is calculated by Scherrer equation using X-ray line broadening method

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Abstract

A process for producing a supported catalyst comprising metal nanoparticles, said process comprises the following steps: (a) preparing a supported catalyst comprising metal nanoparticles; (b) peducing the catalyst of step (a); (c) treating the reduced catalyst of step (b) with at least one alcohol, and (d) calcining the treated catalyst of step (c) to remove carbon species, to produce said supported catalyst. A catalyst obtainable from this process can be used in amination, hydrogenation, dehydrogenation, hydrogenolysis and aerobic oxidation reactions.

Description

PROCESS FOR PRODUCING A CATALYST, CATALYST AND USE THEREOF
The present invention pertains to a process for producing a catalyst having a high dispersion of particles, as well as a catalyst having such a high dispersion and its use in chemical catalytic reactions.
More particularly, the area of the invention is a catalyst comprising metal nanoparticles for heterogeneous catalysis. The particle size of the active phase of a catalyst is one of the most important factors in determining the catalytic behavior of a heterogeneous catalyst in many systems, it has been widely investigated and metal nanoparticles (NP) have merged as a solution for increasing a reaction yield. During this research, it has been further reported that dispersion of catalytic nanoparticles is a strategic parameter. Thus, an increase of the activity for different reactions implementing highly dispersed catalytic nanoparticles is observed.
Traditionally, there are several important ways for preparing highly dispersed metal NP: (i) creation of high amount of nucleation centers using high surface area supports, such as SBA-15, ZSM-5, and MCM-48 [Y. Wan et al., Chem. Rev. (2007) 107, 2821-2860] ; (ii) synthesis of small NP using microemulsion method [J. Lee et al., Chem. Mater. (2008) 20, 5839-5844] ; (iii) in case of supported metal NP, using capping agents such as polyvinylpyrrolidone (PVP) to facilitate the anchoring onto the support resulting in a high metal dispersion [L. Prati et al., Acc. Chem. Res. (2014) 47, 855-863] . However, the main drawbacks of these routes are applications of complicated organic ligands, procedures as well as expensive equipment, which are difficult for large-scale catalysts preparation.
The cobalt based catalysts are among the most popular and important materials for modern chemical industry, which have been widely used in the reactions of Fischer-Tropsch reaction, hydrogenation and dehydrogenation, oxidation and hydrogenolysis. Generally, cobalt NP are prepared based on impregnation (or precipitation process) of Co salts precursors over silica, alumina or active carbon with subsequent calcination under air atmosphere followed by reduction in hydrogen to form active metallic cobalt. Nevertheless, the cobalt NP synthesized by this way, often shows a broad size distribution (20- 200 nm) , which might have a negative effect on the long-term catalyst stability due to higher rate of carbon deposition on larger ones. The reasons for large cobalt particle size with low dispersion would be the poor diffusion rate during impregnation process and easy aggregation after calcination and high temperature reactions. It would be of great interest and a meaningful thing for the development of a simple way to synthesize highly dispersed and ultra-small cobalt NP for industrial applications.
The present invention provides a solution for overcoming this drawback and relates to a process capable of increasing the dispersion of metal nanoparticles at least about 1.5, time, up to twice and even more, in comparison with the parent catalyst involved in this process.
In accordance with F. Niu et al., ACS Catal. (2019) 9, 5986-5997, it is disclosed the positive carbon deposition on a catalyst surface with regards to the selectivity of alcohol amination to primary amines. The authors have developed a method for improving the selectivity of the conversion of aliphatic alcohols into primary amines with NH 3, said method involving a catalyst of gamma-Al 2O 3-supported-Co-NP that is subjected to a treatment with an alcohol after reduction, this treatment intentionally causing the formation of carbon species over the catalyst surface. The thus prepared catalyst is in the form of nanoparticles having a size of about 10 nm, and leads to a significant increase in the amination selectivity.
In a context of always looking for more effective catalyst, the authors have discovered that adding a processing step to a process for manufacturing a catalyst involving a pretreatment with an alcohol as described above, results in an unexpected high dispersion of said nanoparticles in the catalyst, while maintaining its selectivity performance.
The present invention provides a process for producing a catalyst comprising metal nanoparticles, said process comprising the following steps:
(a) preparing a catalyst comprising metal nanoparticles;
(b) reducing the catalyst of step (a) ;
(c) treating the reduced catalyst of step (b) with at least one alcohol, and
(d) calcining the treated catalyst of step (c) to remove carbon species,
to produce said supported catalyst.
This process is surprisingly able to produce a catalyst having a dispersion of the metal nanoparticles which is substantially higher than that of the metal nanoparticles of the catalyst of step (a) . The dispersion of the metal particles  comprised in the catalyst of the invented process reaches advantageously at least about 1.5 time, even about twice in some cases, that of the metal nanoparticles of the catalyst of step (a) . Often, the increase of the dispersion ranges from about 1.5 to about 2 times.
In a particular and advantageous embodiment, the above process is for producing a supported catalyst comprising nanoparticles, therefore the catalyst involved in step (a) is supported and the supported catalyst thus produced has a dispersion of the metal nanoparticles which is at least about 1.5 time that of the metal nanoparticles of said supported catalyst of step (a) .
In one embodiment, the process of the invention enables preparation of a catalyst comprising nanoparticles having a size of 6 nm or less, preferably between 3-6 nm.
It further provides a catalyst having metal nanoparticles which dispersion of the nanoparticles is advantageously at least about 1.5 time that of the corresponding catalyst having metal nanoparticles which is not subjected to a treatment in accordance with the invention. In an embodiment, the invention provides a catalyst which may be obtainable in accordance the process of the invention, said catalyst having a dispersion of the metal nanoparticles which is at least about 1.5 time, even at least about 2 times, and preferably from about 1.5 to about 2 times that of the metal nanoparticles of catalyst of step (a) . In a particular and advantageous embodiment, this catalyst is supported. Also, in an embodiment, the catalyst of the invention comprises nanoparticles having a size of 6 nm or less, preferably between 3-6 nm. Preferably, this catalyst is supported and it comprises nanoparticles having a size of 6 nm or less, preferably between 3-6 nm.
The invention also concerns any use of this catalyst. In particular, this catalyst may catalyze any reaction selected from amination, hydrogenation, dehydrogenation, hydrogenolysis and aerobic oxidation. This catalyst may actually be involved in many reactions, and in particular in any reaction where the corresponding catalyst non-treated in accordance with the invention may be used. The catalyst of the invention will evidence greater performances than the corresponding non-treated catalyst.
Before describing the invention in details, some definitions of the terms hereby use are given.
Nanoparticles are considered as particles having a diameter of no more than 100 nm, preferably no more than 50 nm, even no more than 20 nm. In  accordance with the process of the invention, they may be as small as 10 nm in diameter, preferably 6 nm in diameter and may reach 3 nm in diameter, even less. The diameter of nanoparticles may be measured by any technique well-known from the one skilled in the art. For example, it may be determined by using ex situ X-ray diffraction technique using oxide state of metal catalyst, or by using transmission electron microscopy (TEM) . For TEM analysis, a JEOL 2100 with Filament LaB6 having an acceleration voltage of 200 kV equipped with a camera Gatan 832 CCD may be used. As support, square 230 mesh TEM support grids (copper) may be used. The magnification factor may have a range of '10,000～'600,000. For 50 nm: magnification factor was 40,000～50,000; for 20 nm: 60,000～120,000; for 10 nm : 250,000; for 5 nm : 400,000; for 2 nm: 500,000～600,000. Samples of 0.1 wt. %nanoparticles in methanol suspension are measured. The obtained results are analyzed using the DigitalMicrograph software. For each sample, two pictures are taken and a total of 100 nanoparticles are analyzed. From this size distribution, the average particle size of the nanoparticles is obtained. An appropriate software used to measure the size of the nanoparticles is ImageJ thereby approximating the particles to be spherical. After setting the scale, the maximum diameter of the particles is manually measured one by one to a total number of particles measured of 100.
Metal nanoparticles encompass nanoparticles comprising one metal or more, said metal (s) being in elemental form or a metal compound, or a mixture of a metal in elemental form and a metal compound.
In the description, metal NP essentially refers to NP comprising an active metal having a catalytic function; however, they may comprise one further metal or more that has no catalytic function but may promote it.
The dispersion of a catalyst is expressed by a ratio of NP S to NP T wherein NP S is the number of surface metal NP and NP T is the total number of NP. It may be measured by microscopy or chemisorption technique. These techniques are implemented in the examples.
Some working conditions refer to STP which means Standard Temperature and Pressure.
The invention is below described in details. In this description, it should be considered that, unless otherwise specified, any particular and/or preferred feature may be combined with any one of other particular and/or preferred feature (s) .
The metal of the nanoparticles is particularly selected from transition metals including group 12 metals of the periodic table, and lanthanides and actinides. Preferably, the transition metal is selected from the group consisting of nickel, cobalt, copper, chromium, platinum, palladium, rhodium, ruthenium, iridium, silver, gold, cerium, bismuth, rhenium and any mixture thereof; more preferably it is selected from the group consisting of nickel, cobalt, ruthenium and any mixture thereof, and most preferably it is cobalt, nickel and any mixture thereof.
In some embodiments, the metal catalyst comprises one and only one transition metal in elemental form. In some embodiments, it comprises at least two transition metals in elemental form.
As mentioned above, the metal catalyst may comprise one metal compound or more, particularly at least one transition metal compound. It is preferably selected from the group consisting of metal oxides, salts of metal and any combination thereof. Said salts could be chosen in the group consisting of halide, nitrate, nitrite, carbonate, bicarbonate, sulphate, sulphite, thiosulfate, phosphate, phosphite, hypophosphite, formate, acetate and propionate.
In a particular embodiment, the metal catalyst comprises at least one transition metal in elemental form and its corresponding transition metal oxide.
In accordance with the invention, the catalyst may be supported. The supporting material may be those well-known to the person skilled in the art, which is usually selected from the group consisting of zeolites, Kieselguhr, silica, alumina, silica-alumina, clay, titania, zirconia, magnesia, calcia, lanthanum oxide, niobium oxide, carbon and any combination thereof. It is preferably selected from the group consisting of alumina, carbon and zeolites and more preferably, it is alumina or carbon and most preferably alumina, for example gamma-alumina.
When the catalyst is supported, the metal nanoparticles are dispersed on the support. The metal loading of the supported catalyst may be in a range of 1 to 30 wt. %, preferably 5 to 20 wt. %, mostly preferably 5 to 15 wt. %.
In the following section, steps (a) to (d) of the process are outlined. It should be understood that they involve techniques that are well-known from the one skilled in the art. Thus, the present invention is not restricted to the use of the techniques described below, but it is considered that they are preferred, in particular to produce a catalyst on an industrial scale.
Step (a) regarding the preparation of a catalyst comprising metal nanoparticles, a traditional impregnation or co-precipitation may be performed  with subsequent calcination of the catalyst. Naturally, any other appropriate technique may be carried out in this step.
Step (b) is performed with a reducing gas which may be selected from hydrogen, carbon monoxide and mixtures thereof. This reduction is carried out in the preferred following conditions: at a temperature of 200℃ to 500℃, preferably 200℃ to 450℃ and/or for a period of 1 to 20 hours, preferably 3 to 15 hours. Appropriate conditions may result from any combination of these recommendations.
In step (c) , the supported metal catalyst nanoparticles are treated with at least one alcohol; this alcohol is advantageously selected from (C1-C16) -aliphatic monoalcohols and any mixture thereof. Preferably, the alcohol is selected from propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol and any mixture thereof, more preferably 1-butanol, 1-hexanol, 1-octanol and any mixture thereof. The nanoparticles are treated with said alcohol being in liquid form or in gas form.
Step (c) is performed by contacting catalyst of step (b) with an alcohol in the preferred following conditions: at a temperature from 150 to 400℃, preferably 150 to 300℃, mostly preferably 200 to 300℃ and/or for 0.1 to 8 hours, preferably 0.2 to 7 hours, most preferably 0.25 to 3 hours; appropriate conditions may result from any combination of these recommendations.
Step (d) consists in calcining treated catalyst of step (c) ; as previously mentioned, the implementation of this step unexpectedly results in dispersing catalytic nanoparticles. This step may be conducted at a temperature from 200 to 500℃, preferably 300 to 500℃, mostly preferably 300 to 400℃ and/or for 1 to 5 hours, preferably 2 to 4 hours, most preferably 2 to 3 hours; appropriate conditions that the one skilled in the art is able to determine, may result from any combination of these recommendations.
After calcination step (d) , said supported catalyst is generally recovered. It may then be involved in any appropriate reaction.
Advantageously, a further reduction step is conducted before the supported catalyst is recovered, preferably after step (d) . This step advantageously allows the activation of the prepared catalyst. This reduction step may be carried out in the same conditions as step (b) . Thus, this step may be performed with a reducing gas which may be selected from hydrogen, carbon monoxide and mixtures thereof. This reduction is carried out in the preferred following conditions: at a temperature of 200℃ to 500℃, preferably 200℃ to 450℃  and/or for a period of 1 to 20 hours, preferably 3 to 15 hours. Appropriate conditions may result from any combination of these recommendations.
The invention also provides a catalyst comprising metal nanoparticles having a high dispersion in comparison with the non-treated catalyst. As previously mentioned, it may supported. It comprises nanoparticles that have a size of 6 nm or less, such a size of 3-6 nm. The metal nanoparticles may satisfy any feature previously mentioned in particular regarding the metal (s) , and the catalyst may be supported in any way as described above. Advantageously, such a catalyst is obtainable in accordance with a process as detailed above. One preferred catalyst is a Co-catalyst or a Ni-catalyst, or any catalyst comprising a mixture of Co and Ni.
Any use of a catalyst in accordance with the invention is part of the invention. It may be used for catalyzing a reaction preferably selected from amination, hydrogenation, dehydrogenation, hydrogenolysis and aerobic oxidation.
For illustrative purposes, it may be used in the following reactions:
amination of 1-octanol in 1-octylamine, amination of 2-octanol in 2-octylamine and amination of benzyl alcohol in benzylamine,
hydrogenation reaction of tricosan-12-one [CH 3 (CH 2)  10CO (CH 2)  10CH 3] in tricosan-12-OH [CH 3 (CH 2)  10CHOH (CH 2)  10CH 3] , hydrogenation reaction of octanal in 1-octanol and hydrogenation reaction of octanenitrile in octylamine,
aerobic oxidation reaction of 1-octanol in 1-octanal, aerobic oxidation reaction of 2-octanol in 2-octanone and aerobic oxidation reaction of benzyl alcohol in benzaldehyde.
In these reactions above, it has been illustrated in the following experimental section, where its superiority is demonstrated in comparison with known catalysts.
Advantages of the present invention will merge from the Examples below illustrating some of its embodiments, in support of Figures 1 and 2, wherein:
Figure 1 represents the catalytic performance of a catalyst of the invention (3 vertical bars on the right) in comparison with a catalyst which is not encompasses within the invention (3 vertical bars on the left) , in three chemical reactions.
Figure 2 represents the catalytic stability of a catalyst of the invention in amination of 1-octanol, said stability being evaluated by measuring the conversion rate and selectivity.
Example 1: Preparation of a Co-catalyst involving a process in accordance with the present invention
Step (a) :
The initial Co/Al 2O 3 (10 wt%Co) catalyst was prepared by incipient wetness impregnation (IWI) of γ-Al 2O 3 using an aqueous solution of cobalt nitrate hexahydrate [Co (NO 3)  2·6H 2O] . The impregnated sample was placed for 10 h followed by drying under air at 80℃ overnight and calcined under an air flow [±10 mL (STP) /min] with a heating ramp of 2℃/min from room temperature to 500℃ for 4 h to get the oxidized catalyst.
Step (b) :
The oxidized Co/Al 2O 3 was reduced at 400℃ for 2 h.
Step (c) :
The reduced catalyst was transferred to 30 mL autoclave mixed with 1 g 1-octanol followed by charging 10 bar N 2. The catalyst was treated at 250℃ for 2 h and then washed by ethanol and acetone for several times followed by drying at 80℃ under vacuum for overnight. The catalyst was denoted as “Co-Oct/Al 2O 3” .
Step (d) :
To remove the surface carbonaceous species after 1-octanol pretreatment, the catalyst “Co-Oct/Al 2O 3” was calcined again at 400℃ for 2 h.
The catalyst of step (d) is recovered and analyzed. It is labeled as Co-Oct-Cal/Al 2O 3.
Example 2: Analysis of a Co-catalyst of the invention
Characterization methods:
The ex situ XRD patterns were measured using an X-ray diffractometer (D5000, Siemens) using Cu Kα radiation (λ=0.15418nm) . The scans were recorded in the 2θ range between 10° and 80° using a step size of 0.02° and a step time of 5 s. The catalysts for measurement were all in oxide state. The average Co 3O 4 crystal size were calculated by Scherrer equation using X-ray line broadening method, which could be used for calculation of metallic cobalt size by the formula: d (Co°) =0.75 d (Co 3O 4) .
Thermogravimetric analysis (TGA) was carried out under air flow [10 mL (STP) /min] in the temperature range of 40-800℃ using a heating rate of 5℃/min on a Mettler Toledo SMP/PF7458/MET/600W instrument.
The HAADF-STEM analysis was performed using a Cs-corrected JEOL JEM-2100F microscope operated at 200 keV.
H 2 temperature-programmed reduction (H 2-TPR) was performed by Micromeritics AutoChem II 2920 V30.2 apparatus equipped with a thermal conductivity detector (TCD) using 50 mg sample. The thermal profiles were measured from room temperature to 800℃ with a temperature ramp of 5℃/min under a 5 v/v%H 2/Ar flow [10 mL (STP) /min] .
CO chemisorption measurements were operated on the same instrument. 50 mg of the sample was first reduced under a 5 v/v%H 2/Ar flow [10 mL (STP) /min] for 2 h. After cooling down to room temperature, the activated sample was treated by calibrated pulse of CO-He (5 vol. %CO) till full saturation. The dispersion of cobalt was calculated by division of integrated adsorbed atoms of CO by total amount of cobalt atoms.
The ex situ X-ray photoelectron spectrometry (XPS) was carried out using a PHI 5000 Versa Probe X-ray photoelectron spectrometer with Al Kα radiation, and C 1s (284.6 eV) was used to calibrate the peak position.
Analysis results:
The average particle size of Co 3O 4 is calculated by Scherrer equation using X-ray line broadening method. The calculated size for Co/Al 2O 3 and Co-Oct-Cal/Al 2O 3 are 4.1 nm and 19.6 nm, respectively. Determined from the molar volume correction of size using d (Co°) =0.75 d (Co 3O 4) , the cobalt metal particle size for Co/Al 2O 3 and Co-Oct-Cal/Al 2O 3 are 3.1 nm and 14.7 nm, respectively. This indicates that after 1-octanol pretreatment, the cobalt particle size largely decreases to ultra-small NP.
The particle size, dispersion and morphology were also studied by HAADF-STEM technique. On the TEM images before and after treatment in accordance with the invention (which are not shown) , it is observed the following:
- the fresh Co/Al 2O 3 demonstrates average Co 3O 4 NP of ±20 nm with aggregation in some degree; whereas
- after 1-octanol pretreatment and calcination, the catalyst Co-Oct-Cal/Al 2O 3 shows highly Co 3O 4 dispersion of ±4 nm small NP; the size of individual cobalt NP is consistent with the one calculated from XRD results.
The reducibility of cobalt catalysts before and after 1-octanol pretreatment and calcination was studied by H 2-TPR method. The total H 2 consumption of Co-Oct-Cal/Al 2O 3 (0.92 mmol/g) is slight higher than the fresh Co/Al 2O 3 catalyst (0.87 mmol/g) , which is mainly because the 1-octanol treated and calcined catalyst with smaller highly dispersed NP is much more easier to be  reduced due to higher amount of exposed surface atoms characterized by CO chemisorption.
The Co metal dispersion and surface area were evaluated using CO adsorption in a pulse mode. The metal dispersion of Co-Oct-Cal/Al 2O 3 (2.1%) is nearly two times higher than that of the fresh Co/Al 2O 3 catalyst (1.14%) . The low dispersion (0.41%) of Co-Oct/Al 2O 3 is caused by the surface carbon deposition after 1-octanol pretreatment, which is consistent with the H 2-TPR results.
The above physical properties of these catalysts are reported in Table 1 below:
Table 1
Figure PCTCN2019125530-appb-000001
a The average particle size of Co 3O 4 is calculated by Scherrer equation using X-ray line broadening method
b Determined from the molar volume correction of size using d (Co) =0.75 d (Co 3O 4)
c Determined from randomly selected particles in HAADF-STEM
d The total H 2 consumption from H 2-TPR analysis
e Obtained from CO chemisorption measurement (assuming CO/Co=1)
It is observed that 1-octanol treatment followed by calcination over fresh Co/Al 2O 3 catalyst in accordance with the invention leads to ultra-small cobalt NP with increase of dispersion, in comparison with Co/Al 2O 3 and Co-Oct/Al 2O 3.
Example 3: Uses of a Co-catalyst of the invention
Catalytic tests were conducted for Co-Oct-Cal/Al 2O 3 and for Co/Al 2O 3 as comparison, in the different reactions mentioned below:
√ Amination of 1-octanol in 1-octylamine,
√ Hydrogenation reaction of tricosan-12-one
[CH 3 (CH 2)  10CO (CH 2)  10CH 3] in tricosan-12-OH
[CH 3 (CH 2)  10CHOH (CH 2)  10CH 3] , and
√ Aerobic oxidation reaction of benzyl alcohol in benzaldehyde.
Conditions:
Before each catalytic test, the catalysts obtained and analyzed in Examples 1 and 2 were activated under a pure H 2 flow at 400℃ for 2 h to reduce the cobalt oxide species.
The tests were carried out in a 50 mL stainless steel autoclave as indicated below for each reaction.
For amination of 1-octanol, the reactor was charged with 0.84 g of 1-octanol and 25 mg catalyst followed by charging NH 3 (0.5 g) and H 2 (3 bar) into the reactor. Finally, the reactor was placed on a hot plate equipped with a magnetic stirrer at 180℃ for 2_5 h.
For hydrogenation reaction of tricosan-12-one, the conditions were as follows: tricosan-12-one 0.1 g together with 5 ml ethanol and 10 mg catalyst under H 2 20 bar. The reaction was performed at 120℃ for 10-45 min.
For aerobic oxidation reaction, 1 g benzyl alcohol, 2 g toluene mixed with 20 mg catalyst followed by charging 10 bar O 2 was performed at 130℃ for 1-6 h.
After each test for all the reactions, the reactor was cooled downed to room temperature, and the mixture was filtered and analyzed on an Agilent 7890 GC quipped with a HP-5 capillary column using biphenyl as the internal standard. The stability of the pretreated catalyst was evaluated using amination of 1-octanol. For the typical cycle experiment, after each amination test, the catalyst was washed with ethanol and separated by centrifugation for several times and dried at 80℃ for 10 h followed by activation in H 2 at 400℃ for 2 h for further test.
Results:
Catalytic performance of Co/Al 2O 3 and Co-Oct-Cal/Al 2O 3 in amination of 1-octanol, hydrogenation of tricosan-12-one and aerobic oxidation of benzyl alcohol reactions are evaluated by activity normalized by amount of metal. The results are shown in Figure 1 wherein for each catalyst the first vertical bar corresponds to the amination reaction, the second vertical bar corresponds to the hydrogenation reaction, the third vertical bar corresponds to the oxidation reaction.
The catalytic results show a significant increase of activity of the catalyst of the invention for amination, hydrogenation and oxidation reactions.
Catalytic stability of Co-Oct-Cal/Al 2O 3 in amination of 1-octanol was analyzed in the following reaction conditions: octanol 0.84 g, molar ratio NH 3/alcohol 4.5, pressure (H 2) 3 bar, catalyst 25 mg, reaction temperature 180℃ and time 2 h. The results are shown in Figure 2 wherein for each cycle, the first vertical bar corresponds to the rate of conversion and the second bar corresponds to the selectivity. They evidence that conversion only very slightly decreases with recycling while selectivity remains maximum.
Example 4: Preparation of a Ni-catalyst involving a process in accordance with the present invention
Step (a) :
The initial Ni/Al 2O 3 (10 wt%Ni) catalyst was prepared by incipient wetness impregnation (IWI) of γ-Al 2O 3 using an aqueous solutions of nickel (II) nitrate hexahydrate [Ni (NO 3)  2.6H 2O] . The impregnated sample was placed for 10 h followed by drying under vacuum at 80℃ overnight and calcined under an air at 500℃ for 4 h to get the oxidized catalyst.
Step (b) :
The oxidized Ni/Al 2O 3 of step (a) was reduced at 400℃ for 2 h.
Step (c) :
The reduced catalyst of step (b) is treated by 1-octanol at 250℃ for 2 h and then washed by ethanol and acetone for several times.
Step (d) :
Finally, the washed catalyst was calcined again at 400℃ for 2 h to remove the carbons.
The resulting catalyst was recovered and analyzed; it is labeled as Ni-Oct-Cal/Al 2O 3.
Example 5: Analysis of a Ni-catalyst of the invention
This catalyst was analyzed using the same techniques as those described in Example 2. They are reported in Table 2 below:
Table 2
Figure PCTCN2019125530-appb-000002
a The average particle size of Ni is calculated by Scherrer equation using X-ray line broadening method
b Determined from randomly selected particles in HAADF-STEM
c The total H 2 consumption from H 2-TPR analysis
d Obtained from CO chemisorption measurement
Example 6: Uses of a Ni-catalyst of the invention
Catalytic tests were conducted for Ni-Oct-Cal/Al 2O 3 and for Ni/Al 2O 3 as comparison, in the different reactions mentioned below:
√ Amination of different alcohols: amination of 1-octanol
in 1-octylamine [A1] , amination of 2-octanol in 2-octylamine [A2]
and amination of benzyl alcohol in benzylamine [A3] ,
√ Hydrogenation reaction of tricosan-12-one
[CH 3 (CH 2)  10CO (CH 2)  10CH 3] in tricosan-12-OH
[CH 3 (CH 2)  10CHOH (CH 2)  10CH 3] [H1] ,
hydrogenation reaction of octanal in 1-octanol [H2]
and hydrogenation reaction of octanenitrile in octylamine [H3] ,
√ Aerobic oxidation reaction of 1-octanol in 1-octanal [O1] , of 2-octanol
in 2-octanone [O2] and of benzyl alcohol in benzaldehyde [O3] .
Conditions:
Before each catalytic test, the catalysts obtained and analyzed in Examples 4 and 5 were activated under a pure H 2 flow at 400℃ for 2 h to reduce the nickel oxide species.
The tests were carried out in the same conditions as those described in Example 3.
Results:
The results are shown in tables 3-6 below.
Figure PCTCN2019125530-appb-000003
Figure PCTCN2019125530-appb-000004
Figure PCTCN2019125530-appb-000005
Figure PCTCN2019125530-appb-000006

Claims (20)

  1. A process for producing a supported catalyst comprising metal nanoparticles, said process comprising the following steps:
    (a) preparing a supported catalyst comprising metal nanoparticles,
    (b) reducing the catalyst of step (a) ,
    (c) treating the reduced catalyst of step (b) with at least one alcohol, and
    (d) calcining the treated catalyst of step (c) to remove carbon species,
    to produce said supported catalyst.
  2. The process of claim 1, wherein the nanoparticles of the supported catalyst of step (d) have a size of 6 nm or less, preferably between 3-6 nm.
  3. The process according to claim 1 or 2, wherein the metal of the nanoparticles is selected from the group consisting of nickel, cobalt, copper, chromium, platinum, palladium, rhodium, ruthenium, iridium, silver, gold, cerium, bismuth, rhenium and any mixture thereof.
  4. The process according to claim 3, wherein the metal of the nanoparticles is selected from the group consisting of nickel, cobalt and any mixture thereof.
  5. The process according to any one of the preceding claims, wherein the catalyst is supported, said support being selected from zeolites, Kieselguhr, silica, alumina, silica-alumina, clay, titania, zirconia, magnesia, calcia, lanthanum oxide, niobium oxide, carbon and any mixture thereof.
  6. The process according to claim 5, wherein the support is selected from alumina, carbon and any mixture thereof.
  7. The process according to any one of the preceding claim, wherein step (a) is carried out by impregnation or co-precipitation.
  8. The process according to any one of the preceding claims, wherein step (b) is performed with a reducing gas selected from hydrogen, carbon monoxide  and mixtures thereof, at a temperature of 200℃ to 500℃, preferably 200℃ to 450℃, for 1 to 20 hours, preferably 3 to 15 hours.
  9. The process of any one of the preceding claims, wherein in step (c) , the supported metal catalyst nanoparticles are treated with at least one alcohol selected from (C1-C10) -aliphatic monoalcohols and any mixture thereof.
  10. The process according to claim 9, wherein the alcohol is selected from propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol and any mixture thereof, preferably 1-butanol, 1-hexanol, 1-octanol and any mixture thereof.
  11. The process according to any one of the preceding claims, wherein in step (c) , the alcohol is in liquid form or in gas form.
  12. The process according to claim 11, wherein step (c) is performed by contacting catalyst of step (b) with an alcohol, at a temperature from 150 to 400℃, preferably 150 to 300℃, mostly preferably 200 to 300℃, for 0.1 to 8 hours, preferably 0.2 to 7 hours, most preferably 0.25 to 3 hours.
  13. The process according to any one of the preceding claims, wherein treated catalyst of step (c) is calcined at a temperature from 200 to 500℃, preferably 300 to 500℃, mostly preferably 300 to 400℃, for 1 to 5 hours, preferably 2 to 4 hours, most preferably 2 to 3 hours.
  14. The process according to any one of the preceding claims, wherein a further reduction step is conducted after step (d) before recovering the supported catalyst.
  15. The process according to any one of the preceding claims, wherein said produced supported catalyst has a dispersion of the metal nanoparticles which is at least 1.5 time that of the metal nanoparticles of catalyst of step (a) .
  16. A supported catalyst having metal nanoparticles, said catalyst being obtainable by the process in accordance with any one of claims 1-15.
  17. The catalyst according to claim 16, the nanoparticles of which have a size of 6 nm or less, preferably between 3-6nm.
  18. The catalyst according to claim 16 or 17, wherein the metal of nanoparticles is Co, Ni or any mixture thereof.
  19. A use of the supported catalyst according to any one of claims 16 to 18, for catalyzing a reaction selected from amination, hydrogenation, dehydrogenation, hydrogenolysis and aerobic oxidation.
  20. The use according to claim 19, for catalyzing a reaction chosen from:
    amination of 1-octanol in 1-octylamine, amination of 2-octanol in 2-octylamine, amination of benzyl alcohol in benzylamine,
    hydrogenation reaction of tricosan-12-one [CH 3 (CH 2)  10CO (CH 2)  10CH 3] in tricosan-12-OH [CH 3 (CH 2)  10CHOH (CH 2)  10CH 3] , hydrogenation reaction of octanal in 1-octanol, hydrogenation reaction of octanenitrile in octylamine,
    aerobic oxidation reaction of 1-octanol in 1-octanal, aerobic oxidation reaction of 2-octanol in 2-octanone, and aerobic oxidation reaction of benzyl alcohol in benzaldehyde.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114713236A (en) * 2022-03-30 2022-07-08 郑州大学 Ni-ReOx/TiO2Bimetallic catalyst, preparation method thereof and application thereof in biomass aldehyde selective hydrogenation
CN116328795A (en) * 2021-12-17 2023-06-27 南京林业大学 Preparation method of composite carrier supported bimetallic catalyst for catalyzing selective in-situ hydrogenation of carbon-oxygen double bonds

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007055663A1 (en) * 2005-11-14 2007-05-18 Agency For Science, Technology And Research Highly dispersed metal calatysts
CN104507575A (en) * 2012-08-01 2015-04-08 巴斯夫欧洲公司 Supported noble metal-comprising catalyst for oxidative dehydrogenation or epoxidation
CN109647436A (en) * 2018-12-11 2019-04-19 中科廊坊过程工程研究院 A kind of regeneration method of transition metal decaying catalyst
WO2019205101A1 (en) * 2018-04-27 2019-10-31 Rhodia Operations Process for preparing dispersed pd nanoparticles on a support
WO2019232711A1 (en) * 2018-06-06 2019-12-12 Rhodia Operations Method for amination of alcohol
WO2019232714A1 (en) * 2018-06-06 2019-12-12 Rhodia Operations Method for oxidation of alcohol

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007055663A1 (en) * 2005-11-14 2007-05-18 Agency For Science, Technology And Research Highly dispersed metal calatysts
CN104507575A (en) * 2012-08-01 2015-04-08 巴斯夫欧洲公司 Supported noble metal-comprising catalyst for oxidative dehydrogenation or epoxidation
WO2019205101A1 (en) * 2018-04-27 2019-10-31 Rhodia Operations Process for preparing dispersed pd nanoparticles on a support
WO2019232711A1 (en) * 2018-06-06 2019-12-12 Rhodia Operations Method for amination of alcohol
WO2019232714A1 (en) * 2018-06-06 2019-12-12 Rhodia Operations Method for oxidation of alcohol
CN109647436A (en) * 2018-12-11 2019-04-19 中科廊坊过程工程研究院 A kind of regeneration method of transition metal decaying catalyst

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
ANDREW YUK KEUNG LEUNG, KLAUS HELLGARDT, KING KUOK "MIMI" HII: "Catalysis in Flow: Nickel-Catalyzed Synthesis of Primary Amines from Alcohols and NH3", ACS SUSTAINABLE CHEMISTRY & ENGINEERING, vol. 6, 2 April 2018 (2018-04-02), pages 5479 - 5484, XP055709788, ISSN: 2168-0485, DOI: 10.1021/acssuschemeng.8b00338 *
NIU FENG, XIE SHAOHUA, BAHRI MOUNIB, ERSEN OVIDIU, YAN ZHEN, KUSEMA BRIGHT T., PERA-TITUS MARC, KHODAKOV ANDREI Y., ORDOMSKY VITAL: "Catalyst Deactivation for Enhancement of Selectivity in Alcohols Amination to Primary Amines", ACS CATALYSIS, vol. 9, no. 7, 22 May 2019 (2019-05-22), pages 5986 - 5997, XP055821355, ISSN: 2155-5435, DOI: 10.1021/acscatal.9b00864 *
ZHOU YAGE, BAAZIZ WALID, ERSEN OVIDIU, KOTS PAVEL A., VOVK EVGENY I., ZHOU XIAOHONG, YANG YONG, ORDOMSKY VITALY V.: "Decomposition of Supported Pd Hydride Nanoparticles for the Synthesis of Highly Dispersed Metallic Catalyst", CHEMISTRY OF MATERIALS, vol. 30, no. 22, 2 November 2018 (2018-11-02), pages 8116 - 8120, XP055821356, ISSN: 0897-4756, DOI: 10.1021/acs.chemmater.8b02192 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116328795A (en) * 2021-12-17 2023-06-27 南京林业大学 Preparation method of composite carrier supported bimetallic catalyst for catalyzing selective in-situ hydrogenation of carbon-oxygen double bonds
CN114713236A (en) * 2022-03-30 2022-07-08 郑州大学 Ni-ReOx/TiO2Bimetallic catalyst, preparation method thereof and application thereof in biomass aldehyde selective hydrogenation

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