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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
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
• • 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
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/82—Phosphates
  • B01J29/84—Aluminophosphates containing other elements, e.g. metals, boron
  • B01J29/85—Silicoaluminophosphates [SAPO compounds]
• • 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
• • 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
  • B01J35/70—Catalysts, in general, characterised by their form or physical properties characterised by their crystalline properties, e.g. semi-crystalline
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B37/00—Compounds having molecular sieve properties but not having base-exchange properties
  • C01B37/06—Aluminophosphates containing other elements, e.g. metals, boron
  • C01B37/08—Silicoaluminophosphates [SAPO compounds], e.g. CoSAPO
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
  • C01B39/54—Phosphates, e.g. APO or SAPO compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
  • C07D201/02—Preparation of lactams
  • C07D201/04—Preparation of lactams from or via oximes by Beckmann rearrangement
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
  • C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
  • C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
  • C07D223/08—Oxygen atoms
  • C07D223/10—Oxygen atoms attached in position 2
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D225/00—Heterocyclic compounds containing rings of more than seven members having one nitrogen atom as the only ring hetero atom
  • C07D225/02—Heterocyclic compounds containing rings of more than seven members having one nitrogen atom as the only ring hetero atom not condensed with other rings
• • 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
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
• • 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
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
  • B01J2235/05—Nuclear magnetic resonance [NMR]
• • 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
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
  • B01J2235/10—Infrared [IR]
• • 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
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
  • B01J2235/15—X-ray diffraction
• • 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
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
  • B01J2235/30—Scanning electron microscopy; Transmission electron microscopy
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• the present invention relates to methods of producing lactams, such as caprolactam, for example.
• the present invention relates to a method producing caprolactam utilizing silicoaluminophosphate (SAPO) catalysts.
• SAPO silicoaluminophosphate
• FIG. 1 Traditional approaches for producing lactams, used in the production of nylon, include an oxime undergoing a Beckmann rearrangement in the presence of an acid catalyst, such as fuming sulfuric acid. Exemplary reactions are shown in FIG. 1 . As illustrated in FIG. 1A, cyclohexanone oxime is reacted to form ⁇ - caprolactam. ⁇ -caprolactam in turn is polymerized to form Nylon-6. As illustrated in FIG. 1 B, cyclododecanone oxime is reacted to form ⁇ -laurolactam. ⁇ -laurolactam in turn is polymerized to form Nylon-12. Nylon-6 and nylon-12 are extensively used in industry and manufacturing.
• FIG. 1 C One potential reaction mechanism for the reaction of FIG. 1 A is illustrated in FIG. 1 C.
• the mechanism generally consists of protonating the hydroxyl group, performing an alkyl migration while expelling the hydroxyl to form a nitirilium ion, followed by hydrolysis, tautomerization, and deprotonation to form the lactam.
• Beckmann rearrangement reactions of oximes to form lactams are performed using acids such as fuming sulfuric acid. These reactions are characterized by complete or nearly complete conversion of the oxime and very high selectivity for the desired lactams. However, these reactions also produce byproducts including ammonium sulfate. Although ammonium sulfate is a useful product in itself, minimizing its production may be desirable.
• cyclohexanone oximes are known, which employ various natural and synthetic catalysts including solid-acid catalysts.
• the reported results provide low conversion of the oxime and low selectivity of the desired lactam products.
• the present disclosure provides methods for producing lactams from oximes by performing a Beckmann rearrangement using a silicoaluminophosphate catalyst. These catalysts are used in gas phase or liquid phase reactions to convert oximes into lactams. High conversion of oxime and high selectivity for the desired lactams are produced using the disclosed methods, including high conversion and selectivity for ⁇ -caprolactam produced from cyclohexanone oxime and high conversion and selectivity for ⁇ -laurolactam produced from cyclododecanone oxime.
• the present invention provides a method of performing a Beckmann rearrangement reaction.
• the method comprises reacting an oxime in a liquid phase in the presence of a catalyst to produce a lactam, said catalyst comprising a silicon-containing aluminophosphate with the IZA framework code FAU.
• the present invention provides another method of performing a Beckmann rearrangement reaction.
• the method comprises reacting an oxime in a gas phase in the presence of a catalyst to produce a lactam, said catalyst comprising a silicon-containing aluminophosphates with the IZA framework code FAU; wherein said reacting step further comprises the combination of conversion of oxime and selectivity of the lactam is selected from the group consisting of: the conversion of the oxime is at least 50% and the selectivity of the lactam is at least 90%; and the conversion of the oxime is at least 90% and the selectivity of the lactam is at least 80%.
• the present invention provides a catalyst.
• the catalyst comprises a silicon-containing aluminophosphate framework with the IZA framework code FAU; and a plurality of discrete Bronsted acid sites positioned in an interior of the framework, the acid sites comprising silicon
• the catalyst is a SAPO-37 type catalyst, and at least 10% of the total number of acid sites are characterized as weak acid sites.
• a method of performing a Beckmann rearrangement reaction comprises reacting an oxime in a liquid or gas phase in the presence of a catalyst to produce a lactam, said catalyst comprising a silicon-containing aluminophosphate with the IZA framework code FAU; wherein where the oxime is in a gas phase said reacting step further comprises the combination of conversion of oxime and selectivity of the lactam is selected from the group consisting of: the conversion of the oxime is at least 50% and the selectivity of the lactam is at least 90%; and the conversion of the oxime is at least 90% and the selectivity of the lactam is at least 80%.
• FIG. 1A illustrates the reaction from cyclohexanone oxime to ⁇ - caprolactam
• FIG. 1 B illustrates the reaction from cyclododecanone oxime to ⁇ - laurolactam
• FIG. 1 C illustrates the potential steps of a reaction corresponding to a Beckmann rearrangement reaction from cyclohexanone oxime to ⁇ -caprolactam
• FIGS. 2A-2G illustrate a structures of an exemplary SAPO-37 catalyst
• FIG. 3A is a ternary diagram showing the compositional parameters of one embodiment of the silicoaluminophosphates in terms of mole fractions of silicon, aluminum, and phosphorous;
• FIG. 3B is a ternary diagram showing the compositional parameters of further embodiments of the silicoaluminophosphates in terms of mole fractions of silicon, aluminum, and phosphorous;
• FIGS. 4A-4C correspond to Example 2, and illustrate results from "Si Solid state NMR characterization of SAPO-37 catalysts;
• FIG. 5 corresponds to Example 2, and illustrates results from NH 3 - Temperature Programmed Desorption characterization of SAPO-37 catalysts
• FIG. 6 corresponds to Example 2, and illustrates results from X-Ray Diffraction characterization of SAPO catalysts
• FIG. 7 corresponds to Example 2, and illustrates results from BET surface area characterization of SAPO-37 catalysts
• FIGS. 8A-8C correspond to Example 2, and are SEM pictures of SAPO-37 catalysts
• FIGS. 9-15 correspond to Example 3, and illustrate the conversion and selectivity results of gas phase Beckmann rearrangement reactions of
• FIGS. 16-20 correspond to Example 4, and illustrate the conversion and selectivity results of liquid phase Beckmann rearrangement reactions of cyclohexanone oxime to ⁇ -caprolactam using various catalysts;
• FIGS. 21 and 22 correspond to Example 5, and illustrate the conversion and selectivity results of liquid phase Beckmann rearrangement reactions of cyclododecanone oxime to ⁇ -laurolactam using various catalysts.
• the present disclosure is directed to a method to form lactams from cyclic oxime compounds. Exemplary reactions are shown in FIG. 1 . As illustrated in FIG. 1 A, cyclohexanone oxime is reacted to form ⁇ -caprolactam, which in turn can be polymerized to form Nylon-6. As illustrated in FIG. 1 B, cyclododecanone oxime is reacted to form ⁇ -laurolactam, which in turn can be polymerized to form Nylon-12. In other exemplary embodiments, additional lactams besides ⁇ -caprolactam and ⁇ - laurolactam are produced from corresponding oximes via this method. The present method is also useful to perform other Beckmann rearrangement reactions.
• the methods according to the present disclosure include an oxime reactant undergoing a Beckmann rearrangement reaction in the presence of a catalyst.
• exemplary catalysts include microporous and mesoporous natural and synthetic molecular sieves, zeolites, aluminophosphate (AIPO) materials, and silicoaluminophosphate (SAPO) materials.
• SAPO Silicoaluminophosphate
• SAPO synthetic molecular sieves known to be useful as catalysts.
• Exemplary methods of preparing certain SAPO catalysts are provided in U.S. Patent 4,440,871 to Lok, et al., and N. Jappar, Y. Tanaka, S. Nakata, and T. Tatsumi, "Synthesis and Characterization of a New Titanium Silicoaluminophospate: TAPSO-37," Microporous and Mesoporous
• FIGS. 2A-2G An exemplary structure of one SAPO catalyst, SAPO-37, is illustrated in FIGS. 2A-2G.
• Molecular sieves such as the SAPO-37 catalyst illustrated in FIG. 2A, are crystalline structures having a three-dimensional framework of geometries.
• the frameworks of molecular sieves include cages, cavities, channels, and pores, depending on the type of molecular sieve. Acid sites either on the surface or in the interior or both of the molecular sieve provide the ability for some molecular sieves to act as acid catalysts.
• the portion 10 of the catalyst includes a silicon-containing aluminophosphate geometry with a faujasite-type structure.
• the geometry includes a plurality of pores 12 connecting the interior cavities of the catalyst.
• FIGS. 2A-2G further illustrate an acid site include a silicon atoms 14 in the interior cavities of the catalyst.
• the acid sites further include a hydrogen atom, i.e. a proton 16, which is used in catalyzing the Beckmann rearrangement reaction.
• Silicon atom 14 and proton 16 are enlarged for identification in FIGS. 2A-2G.
• FIGS. 2A-2F illustrate a variety of perspective views of one interior cavity formed by the catalyst 10.
• Fig. 2G shows an enlarged view of an acid site including the silicon atom 14 and proton 16 in the interior of the cage formed by the catalyst 10.
• silicon atom 14 is illustratively attached to four oxygen atoms 18A, 18B, 18C, and 18D, indicating it has isomorphously been substituted for a phosphorous atom in the framework of the catalyst.
• Such an isomorphous substitution is referred to as a type-ll substitution.
• the catalyst contains a plurality of these isomorphously substituted silicon atoms forming acid sites, such that the acid sites are discrete and well- isolated from each other. This exemplary arrangement allows each acid site to function as a well isolated single-site Bronsted acid.
• Catalysts having a greater fraction of type II isomorphous substitution acid sites are typified by higher fractions of weak Bronsted acid sites.
• Higher silicon loaded catalysts are typified by a greater fraction of strong acid sites, which are attributable to type III substitution of two silicon atoms for adjacent aluminum and phosphorous atoms.
• Type III substitution leads to a reduction in available weak Bronsted acid sites.
• Proton 16 is illustratively attached to one of the oxygen atoms 18A.
• the proton 16 can be given up by the acid site to catalyze a reaction in the cavity, such as a Beckmann rearrangement.
• the catalyst is a silicon-containing aluminophosphate with a faujasite-type structure.
• the catalyst is a silicon- containing aluminophosphate or silicoaluminophosphate catalyst with the
• the catalyst is composed of sodalite cages linked together through 6,6 (double-6) secondary building units. Twelve of these sodalite cages are then used to create a super-cage structure of which the pore-aperture is 7.4 A and the internal diameter of the super-cage is in the region of 12-14 A.
• the catalyst further comprises a plurality of discrete Bronsted acid sites positioned in an interior of the framework, the acid sites comprising silicon isomorphously substituted for phosphorous in the framework;
• the catalyst is a silicoaluminophosphate having a microporous crystalline framework structure and whose essential empirical chemical composition in the as-synthesized form on an anhydrous basis is:
• R represents at least one organic templating agent present in the intracrystaline pore system
• m has a value of from 0.02 to 0.3;
• x, y, and z represent, respectively, the mole fraction of silicon, aluminum, and phosphorous present in the oxide moiety; [0041] in one embodiment, the value of x, y, and z being within the compositional area bounded by points A, B, C, D, and E of the ternary diagram which is FIG. 3A representing the values set forth below in Table 1 ;
• the value of x, y, and z being within the compositional area bounded by points a, b, c, d, and e of the ternary diagram which is FIG. 3B representing the values set forth below in Table 2;
• said silicoalumniophosphate having a characteristic X-ray powder diffraction pattern which contains at least the d-spacing set forth below in Table 3.
• SAPO-37 catalysts One exemplary procedure for preparation of SAPO-37 catalysts is as follows. First, an aluminum source, such as aluminum oxide, is slowly added to a phosphorous source, such as 85% phosphoric acid. A structural template solution is prepared by dissolving tetramethylammonium hydroxide pentahydrate (TMAOH) in tetrapropylammonium hydroxide (TPAOH), to which fumed silica is slowly added. The solution is then added dropwise with vigorous stirring to the
• the resulting gel is heated to synthesize the desired structure.
• the resulting product is isolated typically by centrifugation, filtering, and washing. The product is then dried, and calcined, prior to storage in an inert atmosphere.
• the relative loadings of silicon and aluminum can be adjusted to provide a suitable quantity and distribution of acid sites on the surface of and in the interior of the catalyst.
• Exemplary procedures for adjusting the quantity and distribution of acid sites include adjusting the ratio of silicon to phosphorous provided in forming the gel.
• the gel ratio of Si:P is from about 0.1 :1 to about 0.8:1 .
• the gel ratio of Si:P is from about 0.1 1 :1 to about 0.63:1 .
• the gel ratio of Si:P is as little as 0.1 :1 , 0.1 1 :1 , 0.16:1 , 0.17:1 , 0.21 :1 , 0.22:1 , or as great as 0.42:1 , 0.63:1 , 0.75:1 , 0.8:1 , or within any range defined between any pair of the foregoing values.
• the weight percentage of silicon in the formed catalyst can also be determined.
• An exemplary method for determining the weight percentage of silicon is by inductively coupled plasma.
• silicon comprises from about 1 wt % to about 10 wt % of the total weight of the catalyst.
• silicon comprises from about 2 wt % to about 9.1 wt % of the total weight of the catalyst.
• silicon comprises a weight percentage of the total weight of the catalyst up from as little as 1 wt %, 1 .5 wt %, 2 wt %, 2.1 wt %, 2.5wt % to as much as 6 wt %, 7 wt %, 8 wt %, 9 wt %, 9.1 wt%, 10 wt %, or within any range defined between any pair of the foregoing values.
• Oximes are converted to lactams, such as in the examples illustrated in FIGS. 1A and 1 B, through contact with the catalysts.
• the present disclosure is believed to be generally applicable to any oxime generated from a variety of aldehydes and ketones.
• Exemplary oximes include, but are not limited, to
• cyclohexanone oxime cyclododecanone oxime
• the reaction is performed in the presence of a solvent.
• a solvent Although working examples are provided for reactions performed in a solvent, the present disclosure is believed to also be applicable for Beckmann rearrangement reactions performed in the absence of a solvent.
• the product In reactions performed in the absence of a solvent, the product is used to absorb the exothermic heat produced by the reaction. In these embodiments, a large ratio of lactam to oxime is maintained in the reaction area to absorb the energy produced by the reaction.
• Exemplary solvents include organic nitriles of the formula:
• R 1 represents CrC 8 -alkyl, C C 8 -alkenyl, C C 8 -alkynyl, C 3 -C 8 - cycloalkyl; C3-C 8 -aralkyl including a C6 aromatic ring.
• exemplary nitriles include acetonitrile, benzonitrile and mixtures of any of the foregoing.
• exemplary solvents include aromatic compounds of the formula:
• Ar is an aromatic ring and R 2 represents H, F, CI, or Br.
• Exemplary aromatic solvents include benzene and chlorobenzene.
• Still other exemplary solvents include water and alcohols of the formula:
• R 3 represents a hydrogen, d-Ce-alkyl, CrC 8 -alkenyl, Ci-C 8 - alkynyl, C 3 -C 8 -cycloalkyl; C 3 -C 8 -arylalkyl.
• exemplary alcohols include alcohols of 8 or fewer carbon atoms such as methanol, ethanol, n-propanol, iso-propanol, n- butanol, sec-butanol, isobutanol, tert-butanol, n-amyl alcohol, n-hexanol, phenol, and mixtures of any of the foregoing.
• the solvent is rigorously dried prior to contact with the catalyst.
• rigorously dried is understood to mean dried to a level of 100 ppm water or less.
• Exemplary methods of drying include adsorption of water using molecular sieves, such as Activated 4A molecular sieves.
• a reaction performed in the absence of water means a reaction in which water comprises less than 0.01 wt% of the weight of the reactants.
• the reaction is performed as a liquid phase reaction or a gas phase reaction.
• a liquid phase reaction in a reaction in which substantially all of the oxime is in the liquid phase when reacted to form the lactam.
• a gas phase reaction in a reaction in which substantially all of the oxime is in the gas or vapor phase when reacted to form the lactam.
• the reaction When performed as a gas phase reaction, the reaction is typically performed at a temperature beneath 350°C. In a more particular embodiment, the reaction is performed at a temperature from about 130°C to about 300°C. In still other embodiments, the reaction may be performed at a temperature as low as about 90°C, 100°C, 1 10°C, 120°, 130°, or as high as about 140°C, 150°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C 250°C, 275°C, 300°C, 325°C, 350°C, or within any range defined between any pair of the foregoing values.
• the reaction When performed as a gas phase reaction, the reaction is typically perfored at a pressure from about 0.1 bar to about 1 bar. More particularly, in exemplary embodiments of the reaction performed as a gas phase reaction, the pressure may be as low as 0.01 bar, 0.02 bar, 0.05 bar, 0.1 bar, as high as 0.5 bar, 1 bar, or within a range defined between any pair of the foregoing values.
• the reaction When performed as a liquid phase reaction, the reaction is typically performed at a temperature beneath 250°C. In a more particular embodiment, the reaction is performed at a temperature from about 130°C to about 190°C. In still other embodiments, the reaction may be performed at a temperature as low as about 90°C, 100°C, 1 10°C, 120°, 130°, or as high as about 140°C, 150°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C 250°C, or within any range defined between any pair of the foregoing values.
• the reaction When performed as a liquid phase reaction, the reaction is typically performed at a pressure from about 1 bar to about 5 bar. More particularly, in some exemplary embodiments, the pressure may be as low as 0.5 bar, 1 bar, as high as 1 bar, 2 bar, 5 bar, 10 bar, 15 bar, 20 bar, 25 bar, 30 bar, 35 bar, or within any range defined between any pair of the foregoing values.
• the solvent is typically a gas at the reaction temperature, but is maintained in the liquid phase by performing the reaction at an elevated pressure.
• the reaction When performed as a liquid phase reaction, the reaction is typically performed at a temperature and pressure below the critical point of the solvent, where the pressure may be as low as 1 bar, as high as 2 bar, 5 bar, 10 bar, 15 bar, 20 bar, 25 bar, 30 bar, 35 bar, or within any range defined between any pair of the foregoing values.
• the efficiency of the reaction may be expressed in terms of conversion of oxime, selectivity of the desired product, or yield. Conversion is a measure of the amount of oxime reactant that is consumed by the reaction. Higher conversions are more desirable. The conversion is calculated as:
• Selectivity is a measure of the amount of the desired product that is produced relative to all reaction products. Higher selectivities are more desirable.
• Yield is a measurement that combines selectivity and conversion.
• Yield indicates how much of the incoming oxime is reacted to form the desired lactam. The yield is calculated as:
• the conversion is 50% or higher. In a more particular embodiment, the conversion is from about 50% to about 100%. For example, the conversion may be as low as about 50%, 60%, 70%, 75%, or as high as about 80%, 85%, 90%, 95%, 97.5%, 99%, 99.5%, approaching 100%, or 100%, or may be within any range defined between any pair of the foregoing values.
• the selectivity is 50% or higher. In a more particular embodiment, the conversion is as low as about 50%, 55%, 60%, 65%, or as high as about 70%, 75%, 80%, 85%, 90%, 95%, 97.5%, 99%, 99.5%,
• the conversion of cyclohexanone oxime to ⁇ - caprolactam is from about 90% to about 100% and the selectivity is from about 80% to about 100%. In more particular embodiments, the conversion is from about 95% to about 100% and the selectivity is from about 90% to about 98%. In still more particular embodiments, the conversion is from about 98% to approaching 100% and the selectivity is from about 95% to about 98%.
• the conversion of cyclododecanone oxime to ⁇ -laurolactam is from about 90% to about 100% and the selectivity is from about 80% to about 100%. In more particular embodiments, the conversion is from about 95% to about 100%, and the selectivity is from about 98% to about 99%.
• a pseudo-boehmite phase of aluminum oxide was slowly added to a diluted solution of phosphoric acid (85 wt%) and left to stir for 7 hours.
• a second solution of tetramethylammonium hydroxide pentahydrate (TMAOH) dissolved in tetrapropylammonium hydroxide (TPAOH) (40 wt%) was prepared to which fumed silica was slowly added. This was left to stir for 2 hours and was then added dropwise to a stirred aluminum/phosphorous gel.
• SAPO-37 catalysts were prepared with four different loadings of Si0 2 . The catalysts were labeled based on the ratio of Si0 2 to H 3 P0 4 used in the preparation. Gel loadings for the various samples can be found in Table 4 below.
• FIG. 4A shows the results of 2D MAS 29 Si NMR of SAPO-37(0.21 ).
• FIG. 4B shows the results of 2D MAS 29 Si NMR of SAPO-37(0.63).
• FIG. 4C shows the results of MAS 29 Si NMR of SAPO-37 systems of different gel-ratios.
• FIG. 4C shows the presence of isolated Si(OAI) 4 sites at -93 ppm and Si(OAI) 3 (OSi) sites at -98 ppm.
• FIGS. 4A-4C illustrate that silicon begins to cluster at higher loadings.
• FIGS. 4A shows low to no peaks at -103 ppm corresponding to a cluster of two sites, and at -108 ppm, corresponding to a cluster of three sites.
• FIGS. 4B and 4C at higher levels of silicon loading, the silicon begins to cluster, forming peaks at -103 ppm - Si(OAI) 2 (OSi) 2 and -108 ppm, Si(OAI)(OSi) 3 .
• Lower silicon loadings such as using SAPO-37 (0.21 ) as shown in FIGS. 3A and 3C, reduces the peak at - 98 ppm, indicating a higher prevalence of isolated single sites with weak Bronsted acidity over clusters of multiple sites.
• TPD temperature programmed desorption
• ammonia is adsorbed onto the surface of the catalyst, binding to the acid sites, giving a defined peak.
• the area of this peak corresponds to the quantity of ammonia in the system.
• the system is then heated and the ammonia desorbs with the temperature. The stronger the acid site, the higher the temperature required to desorb the ammonia.
• SAPO-37(0.21 ) ⁇ SAPO-37(0.42) > SAPO-37(0.63)
• both the NH 3 -TPD and FT-IR CO probe data suggest that SAPO-37(0.63) has the strongest acid sites and SAPO-37(0.21 ) has the weakest.
• the NH 3 -TPD suggested that SAPO-37(0.21 ) and SAPO-37(0.42) had more weak sites (desorption at 200-300°C and 300-400°C) than SAPO-37(0.63), but SAPO-37(0.63) had more strong acid sites (400-500°C) than either SAPO-37(0.21 ) or SAPO-37(0.42).
• collidene is adsorbed onto the surface of the catalyst, binding to the acid sites, giving a defined peak.
• the area of this peak corresponds to the quantity of collidene in the system.
• the system is then heated and the collidene desorbs with the temperature. The stronger the acid site, the higher the temperature required to desorb the collidene. Weak sites are
• medium sites are characterized as collidene desorbs between 300° and 450°C
• strong sites are characterized as still having collidene adsorbed at 450°C.
• Table 6 shows that the total acidity as measured by the total number of acid sites is:
• the weak and medium sites both showed higher numbers for the SAPO-37(0.21 ) than SAPO-37(0.63).
• the strength of the SAPO- 37(0.42) weak acid sites and the SAPO-37(0.63) for strong acid sites does not perfectly align with the other acid investigations, but the medium site data is nearly equivalent for SAPO-37(0.21 ) and SAPO-37(0.42).
• the SAPO-37 unit cell was optimized using CRYSTAL09 package to perform ab initio calculations of crystal system, R. Dovesi, R. Orlando, B. Civalleri, C. Roetti, V. R. Saunders, and C. M. Zicovich-Wilson, Z. Kristallogr. 220, 571 (2005).
• the SAPO-37 unit cell contained 577 atoms with the formula H-iSi-iAlgePgsC . This corresponds to a 1 mol% loading of silicon.
• a unit cell was modeled with NH 3 present such that it could interact with the acid site (H 4 NiSiiAlg6P95038 4 )- Using the following equation the binding energy of NH 3 with SAPO-37 was estimated to be 1 17 kJ mol "1 :
• E bind E(SAPO-37 + NH 3 ) - E(SAPO-37) - E(NH 3 )
• AFI X-ray diffraction pattern of the catalyst SAPO-5
• the three higher loading samples were found to be phase-pure, but SAPO-37(0.1 1 ) showed a significant AFI impurity phase.
• the SAPO-37(0.1 1 ) showed peaks corresponding to both FAU-type framework at 1 1 1 and 331 , as well as IZA AFI-type framework at 100 and 200.
• the results of powder X-ray diffraction can be found in FIG. 6.
• the ratio of silicon to phosphorous in the gel used to form the catalysts for SAPO-37(0.63) and SAPO-37(0.21 ) was 0.63:0.21 , or 3:1 .
• the silicon weight percentage of SAPO-37(0.63) was higher than the silicon weight percentage of SAPO-37(0.21 ).
• the ratio of silicon weight percentage between SAPO-37(0.63) and SAPO-37(0.21 ) was 9.1 :2, or 4.55:1 . This was higher than the gel loading ratio of 3:1 .
• FIG. 8A An SEM image of SAPO- 37(0.21 ) is provided as FIG. 8A, an SEM image of SAPO-37(0.42) is provided as FIG. 8B, and an SEM image of SAPO-37(0.63) is provided as FIG. 8C.
• SAPO-37 catalysts were made as in Example 1 .
• SAPO-5 was prepared by diluting 4.7 g of H 3 P0 4 (85% in H 2 0) in a Teflon beaker with 10 ml of H 2 0 and stirred until homogeneous (5 minutes). 4.3 g of AI(OH) 3 was slowly added to the acid, followed by a further 10ml of H 2 0. The mixture was stirred for 10 minutes. 0.76 g of fumed silica was slowly added, followed by 10 ml of H 2 0. The mixture was stirred for 30 minutes. Finally the templating agent (N- Methyl-dicyclohexyl-amine) was added dropwise and a further 10 ml of H 2 0 was added. The mixture was stirred for 1 hour.
• the white gel was then transferred to an autoclave and heated to 200 °C for 2 hours. On removal, the gel was filtered and washed with H 2 0 and left to dry at 70 °C overnight. The white solid produced was calcined at 550 °C for 10 hours before use.
• SAPO-TRY was prepared in the same manner as the SAPO-5 above, except that no templating agent was used.
• SAPO-34 catalyst was prepared according to the method provided by D. Dubois, et al., Fuel Process. Technol. 2003, 83, 203, the disclosures of which are hereby incorporated by reference.
• TS-1 a titanium silicalite zeolite-based catalyst was obtained from the National Chemical Laboratory, Pune India. The sample has a Ti loading of 2 wt %.
• the TS-1 catalyst is disclosed in U.S. Patent 4,859,785, the disclosure of which is hereby incorporated by reference.
• the conversion and selectivity of the system was analyzed using a Clarus 400 gas chromatogram with FID and using an Elite 5 column, the peak areas were calibrated using known response factors.
• the method was: start at 12CTC, hold for 2 minutes, then ramp at 15°C/min up to 220°C, and hold for 5 minutes at 220°C.
• the method was 13 minutes and 40 seconds long in total.
• the cyclohexanone oxime has a peak corresponding to a retention time of 4.0 minutes
• ⁇ -caprolactam peak has a peak corresponding to a retention time of 5.8 minutes
• the by-product has a peak corresponding to a retention time of 6.6 minutes.
• the injector port was set to 220°C and the detector was set to 250°C.
• the carrier pressure (Helium) was 14 psig. The method was given 1 minute to equilibrate before injection. A centrifuged sample of 5 ⁇ was injected.
• the samples were calibrated using a relative response factor of ⁇ - caprolactam relative to cyclohexanone oxime, which was found to be 1 .1 19.
• the samples were calibrated to an internal standard of chlorobenzene for the mass balance. Cyclohexnaone oxime was found to have a relative response factor of 1 .2972 relative to chlorobenzene, and ⁇ -caprolactam was found to have a response factor of 1 .4516 relative to chlorobenzene.
• the mass balance at 130°C was found to be 106% after 6 hours.
• the response factors were used to calculate the moles of cyclohexanone oxime, ⁇ -caprolactam, and by-products (response factor assumed to be 1 .00):
• a cylindrical glass tube (4 mm in diameter) with a glass frit was packed with a 5 mm layer of glass beads, a layer of pelletized catalyst (-0.25 g, 40 mm) and a further 60 mm layer of glass beads, was placed inside a flow reactor heated by a jacket to 673 K. The sample was then treated under a flow of Helium gas for 1 hour. The temperature was dropped to the test temperature as set forth below and a liquid feed of 10 wt% cyclohexanone oxime in ethanol was fed into the reactor, maintaining the experimental weight hour space velocity (WHSV) as set forth below.
• WHSV weight hour space velocity
• SAPO-37 (0.42) catalyst produced much higher conversion and selectivity results than any of the other SAPO catalysts tested.
• SAPO-37(0.22) results are shown in FIG. 10.
• SAPO-37(0.22) resulted in high conversions and selectivity. Conversion increased as temperature increased from 300° to 350°. Selectivity also increased, but was above 80% in at all three measured temperatures.
• the SAPO-41 provided high conversion, but much lower selectivity to the ⁇ -caplrolactam than the SAPO-37 catalysts.
• FIG. 13 The results for TS-1 are shown in FIG. 13. Conversion and selectivity were high for TS-1 at 300°C.
• FIGS. 14 and 15 compare the results from the various catalysts at the same temperatures.
• SAPO-37 catalysts were made as in Example 1 .
• SAPO-5 and SAPO-34 catalysts were made as in Example 3.
• SAPO-1 1 catalyst was made according to P. Meriaudeau, V. A. Tuan, V. T. Nghiem, S. Y. Lai, L. N. Hung and C. Naccache, Journal of catalysis, 1997, 169, 55-66, the disclosure of which is hereby incorporated by reference.
• SAPO-41 catalyst was made according to P. Meriaudeau, V. A. Tuan, V. T. Nghiem, S. Y. Lai, L. N. Hung and C. Naccache, Journal of catalysis, 1997, 169, 55-66, the disclosure of which is hereby incorporated by reference.
• Samples were injected into a Perkin Elmer a HP1 cross linked methylsiloxane (30 m x 0.32 mm x 1 ⁇ film thickness) column. The samples were mass balanced using chlorobenzene as an internal standard.
• Liquid phase runs were made for various catalysts under similar conditions. The conditions selected were 130°C, with a catalyst: cyclohexanone oxime: benxonitrile ratio of 1 :1 :200, and 0.1 g of cyclohexanone oxime. The samples were analyzed after 7 hours.
• SAPO-37 and SAPO-5 frameworks have similar pore diameters, the former 7.4 A, the latter 7.3 A, yet they showed very different levels of activity, therefore the environments were probed using 29 Si MAS NMR techniques.
• the SAPO-37 spectrum showed a dominant peak at -93 ppm, with a smaller secondary peak at -98 ppm, corresponding to Si(OAI) 4 and Si(OSi)(OAI) 3 environments respectively.
• the Si(OAI) 4 environment shows that the silicon has substituted a single phosphorus atom, therefore generating a Bronsted acid site (a type II substitution mechanism)
• the Si(OSi)(OAI) 3 environment shows that two silicons have substituted a phosphorus and aluminium pair, therefore not generating an acidity (type III substitution mechanism).
• the SAPO-5 spectrum showed a dominant peak at -1 10 ppm, corresponding to a Si(OSi) environment, suggesting the silicon was present mostly in siliceous zones. This showed that the isolated silicon sites are the active site for this reaction.
• the silicon content of the SAPO-37 species was varied (denoted SAPO-37(X) where X is the as-synthesised gel ratio), giving three different samples, which showed subtle differences in catalytic performance.
• FIG. 17 illustrates the high conversion and selectivity using the SAPO- 37 (0.16) catalyst in a liquid phase reaction using benzonitrile as solvent.
• the reaction was performed at 130°C, with a catalyst: cyclohexanone oxime: benzonitrile ratio of 1 :1 :200, with 0.1 g of cyclohexanone oxime used, and performed for 7 hours.
• FIG. 18 illustrates the same reaction using anhydrous benzonitrile as solvent.
• the reaction was performed at 130°C, with a catalyst: cyclohexanone oxime: anhydrous benzonitrile ratio of 1 :1 :200, with 0.125 g of cyclohexanone oxime used, and performed for 7 hours.
• the anhydrous benzonitrile shown in FIG. 18 resulted in greater selectivity but lower conversion than the (wet) benzonitrile shown in FIG. 17. Both FIGS. 17 and 18 show high conversion and selectivity in a liquid phase reaction.
• FIG. 19 illustrates a lower conversion and selectivity for a liquid phase reaction with SAPO-1 1 as the catalyst.
• the reaction was performed at 130°C, with a catalyst: cyclohexanone oxime: benzonitrile ratio of 1 :1 :200, with 0.1 g of
• FIG. 20 illustrates an even lower conversion and selectivity for a liquid phase reaction with SAPO-41 as the catalyst.
• the reaction was performed at 130°C, with a catalyst: cyclohexanone oxime: benzonitrile ratio of 1 :1 :200, with 0.1 g of cyclohexnone oxime used, and run for 7 hours.
• Table 12 presents the conversion, selectivity, and yield for SAPO-37 catalysts with various gel loadings at time intervals during the reaction.
• Table 13 presents the final conversion and selectivity values taken for each catalyst at the indicated temperature.
• SAPO-37(0.21 )AN designates the use of anhydrous benzonitrile as the solvent.
• SAPO-37(0.21 ) 150 75 97.2 92.5 89.9 SAPO-37(0.21 ) 150 90 98.7 93.7 92.4
• SAPO-37(0.21 ) 150 135 99.8 92.5 92.3
• SAPO-37(0.21 ) 150 150 99.9 92.7 92.6
• SAPO-37(0.42) 150 105 96.6 90.1 87.1
• SAPO-37(0.42) 150 99.0 89.5 88.7
• SAPO-37(0.42) 150 165 99.3 90.6 90.0
• SAPO-37(0.63) 150 165 98.6 85.0 83.8
• SAPO-37(0.63) 150 210 99.4 83.8 83.4
• SAPO-37(0.63) 150 225 99.6 83.7 83.3
• SAPO-37(0.21 ) 170 5 27.2 97.1 26.4 SAPO-37(0.21 ) 170 10 57.9 92.7 53.7
• SAPO-37(0.42) 170 20 75.0 94.9 71.2
• SAPO-37(0.21 ) 190 10 72.0 98.0 70.5
• SAPO-37(0.21 ) 190 45 99.7 92.4 92.1 SAPO-37(0.21 ) 190 50 99.8 89.6 89.4
• SAPO-37(0.42) 190 5 29.5 100.0 29.5
• SAPO-37(0.42) 190 10 66.4 100.0 66.4
• SAPO-37(0.42) 190 60 100.0 90.6 90.6
• Tables 12 and 13 indicate high levels of conversion and selectivity using SAPO-37 as the catalyst and benzonitrile as the solvent in a liquid phase reaction.
• the data in Tables 12 and 13 show conversion greater than 97.5% within the measured times, while selectivity for ⁇ -caprolactam ranged from about 80% for SAPO-37(0.63) at 190°C to about 98% for SAPO-37(0.21 ) at 130°C in anhydrous benzonitrile.
• the SAPO-37(0.21 ) provided higher selectivity than the SAPO-37(0.42), which in turn provided higher selectivity than the SAPO-37(0.63), although high selectivity and conversion were seen for all three catalysts.
• the Beckmann rearrangement is also known to be useful in producing ⁇ -laurolactam from cyclododecanone (see FIG. 1 B).
• FIG. 21 illustrates very high conversion and selectivity using SAPO-37 as the catalyst
• FIG. 22 illustrates much lower conversion and selectivity using SAPO-37 as the catalyst.
• the only notably by-product found using SAPO-37 was cyclododecanone.

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