Methods for preparing C-4 sugars and keto sugars

Abstract

Various methods are described for preparing C4 aldoses and / or their ketones. Various methods are described for preparing C4 aldoses and / or their ketones from feed compositions comprising glycolaldehyde. Also described are various methods for preparing useful downstream products and intermediates, such as erythritol and erythronic acid, from C4 aldoses and / or their ketones.

Description

[Technical field]

[0001] The present invention relates to various processes for preparing C4 aldoses and / or their ketones. The present invention further relates to various processes for preparing useful downstream products and intermediates, such as erythritol and erythronic acid, from C4 aldoses and / or their ketones. [Background technology]

[0002] 2. Background of the Invention Pyrolysis of glucose (dextrose) and other carbohydrate feedstocks produces reaction products including various aldehyde compounds such as glyoxal, pyruvaldehyde, acetol, ethylene glycol, and glycolaldehyde. Of these compounds, glycolaldehyde is generally considered to be the most useful (see, e.g., WO 88 / 00935 A1). Glycolaldehyde can be used as is, such as in the manufacture of liquid smoke (as described, e.g., in U.S. Pat. No. 6,074,679), or as a precursor reagent in the synthesis of methionine (see, e.g., U.S. Pat. No. 10,189,778). However, there remains a need for additional reactions and effective methods that can utilize glycolaldehyde as a starting material to more fully capture the value of this compound. Summary of the Invention [Means for solving the problem]

[0003] Summary of the Invention Various aspects of the invention are directed to methods for preparing C4 aldoses and / or ketones thereof. In some embodiments, the methods include contacting a feed composition comprising glycolaldehyde with a catalyst comprising an imidazolate framework (e.g., a zeolitic imadazolate framework (ZIF) or a boron imidazolate framework (BIF)) in a reaction zone to condense at least a portion of the glycolaldehyde to obtain C4 aldoses and / or ketones thereof.

[0004] Another aspect is directed to a method for producing a feed composition having an improved yield of glycolaldehyde by catalytic pyrolysis of carbohydrates and then preparing C4 aldoses and / or ketones thereof from the feed composition thus produced. In some embodiments, the preparation of the C4 aldoses and / or ketones thereof comprises contacting the feed composition with a catalyst comprising an imidazolate framework (e.g., a zeolitic imadazolate framework (ZIF) or a boron imidazolate framework (BIF)) in a reaction zone to condense at least a portion of the glycolaldehyde in the feed composition, and an improved yield of glycolaldehyde to C4 aldoses and / or ketones thereof is shown.

[0005] Further aspects are directed to methods for preparing erythritol and / or threitol. In various embodiments, the methods include preparing erythrose and / or threose by the methods described herein; and hydrogenating at least a portion of the erythrose and / or threose to form erythritol and / or threitol.

[0006] Yet another aspect is directed to a method for preparing erythronic acid, threonic acid, and / or salts thereof. In some embodiments, the method includes preparing erythrose and / or threose by a method described herein; and oxidizing at least a portion of the erythrose and / or threose to form erythronic acid, threonic acid, and / or salts thereof.

[0007] Yet another aspect is directed to methods for preparing downstream products, comprising preparing a C4 aldose and / or ketone thereof by the methods described herein; and converting the C4 aldose and / or ketone thereof to a downstream product or a precursor thereof, the downstream product being a compound selected from the group consisting of glyceraldehyde; methyl vinyl glycolate; 2-hydroxy-4-methoxybutanoate; 2-hydroxy-4-methoxybutanoic acid; 1,4-butanediol; α-hydroxy-γ-butyrolactone, methionine, and analogs thereof.

[0008] Other objects and features will be in part apparent and in part pointed out hereinafter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Detailed Description of the Preferred Embodiments The present invention relates to various processes for the preparation of C4 aldoses and / or their ketones. The present invention further relates to various processes for the preparation of useful downstream products and intermediates, such as erythritol and erythronic acid, from C4 aldoses and / or their ketones (i.e., C4 sugars and keto sugars).

[0010] In certain embodiments of the method of the present invention, it has been found that C4 sugars and their corresponding ketones, such as threose, erythrose, and erythrulose, are selectively produced with high conversion from a feed composition containing glycolaldehyde. In particular, for these embodiments, it has been found that by using a catalyst containing an imidazolate framework (e.g., a zeolitic imidazolate framework (ZIF) or a boron imidazolate framework (BIF)), glycolaldehyde can be condensed into one or more C4 aldoses and / or ketones in high yield and / or selectivity. It has also been found that these catalysts can reduce the reaction time, thereby advantageously increasing the productivity of the catalyst and the economics of the process. Thus, various methods for preparing C4 aldoses and / or their ketones include contacting a feed composition containing glycolaldehyde with a catalyst containing an imidazolate framework in a reaction zone to condense at least a portion of the glycolaldehyde to obtain C4 aldoses and / or their ketones.

[0011] Condensation Catalyst As described, the condensation reaction in a preferred embodiment of the method described herein is carried out in the presence of a catalyst comprising an imidazolate framework. The imidazolate framework comprises one or more metals and / or metalloids bound by an imidazolate / imidazolate-type binding group. For example, the one or more metals and / or metalloids can include zinc, cobalt, copper, iron, lithium, boron, and combinations thereof. In various embodiments, the imidazolate framework comprises zinc. In some embodiments, the imidazolate framework comprises boron. The binding group can be, for example, imidazolate (IM), 2-methylimidazolate (MIM), 2-ethylimidazolate (EIM), and benzimidazolate (BIM).

[0012] In various embodiments, the catalyst comprises an imidazolate framework comprising a zeolitic imidazolate framework (ZIF) or a boron imidazolate framework (BIF). In various embodiments, the catalyst comprises a ZIF. In some embodiments, the catalyst comprises a BIF. In some embodiments, the catalyst comprises an imidazolate framework selected from the group consisting of ZIF-4, ZIF-8, ZIF-14, BIF-2Li, BIF-2Cu, BIF-5, and combinations thereof. In certain embodiments, the catalyst comprises an imidazolate framework comprising ZIF-4 (ZnIM2). In some embodiments, the catalyst consists essentially of ZIF-4 (e.g., 95% by weight or more, or 99% by weight or more of the total catalyst weight). In some embodiments, the catalyst consists of ZIF-4.

[0013] The imidazolate framework can be prepared from precursors that include imidazole and / or imidazole-type compounds (e.g., 2-methylimidazole, 2-ethylimidazole, and benzimidazole) in combination with one or more salts (e.g., metal nitrates). In various embodiments, the imidazolate framework is prepared from precursors that include imidazole and zinc nitrate hexahydrate.

[0014] In various embodiments, the imidazolate framework and / or catalyst is essentially free of tin, zirconia, and / or silica (e.g., containing 1 wt. % or less, preferably 0.1 wt. % or less, or even 0.01 wt. % or less of the total catalyst weight). In various embodiments, the imidazolate framework and / or catalyst is free of tin, zirconia, and / or silica. In some embodiments, the imidazolate framework and / or catalyst is free of or essentially free of tin. In further embodiments, the imidazolate framework and / or catalyst is free of or essentially free of zirconia. In some embodiments, the imidazolate framework and / or catalyst is free of or essentially free of silica.

[0015] Further, in some embodiments, the reaction zone is essentially free of (e.g., containing 1 wt. % or less, preferably 0.1 wt. % or less, or even 0.01 wt. % or less of the total catalyst weight) zeolite catalysts, including pentasil zeolites such as ZSM-5 and ZSM-11. In certain embodiments, the reaction zone is free of zeolite catalysts, including pentasil zeolites.

[0016] supply material As described, in all embodiments, the feed composition used to prepare the C4 aldoses and / or ketones thereof comprises glycolaldehyde. For example, the feed composition can comprise a glycolaldehyde concentration of 1 wt.% or more, 5 wt.% or more, 10 wt.% or more, 20 wt.% or more, 30 wt.% or more, 40 wt.% or more, 50 wt.% or more, 60 wt.% or more, or 70 wt.% or more. In some embodiments, the feed composition comprises a glycolaldehyde concentration of 1 wt.%-70 wt.%, 1 wt.%-50 wt.%, 1 wt.%-25 wt.%, or 1 wt.%-10 wt.%. In various embodiments, the feed composition further comprises water (e.g., the feed composition is an aqueous solution comprising glycolaldehyde).

[0017] The glycolaldehyde of the feed composition can be obtained by a pyrolysis process in which carbohydrates such as glucose are converted to shorter chain compounds. Various examples of such processes are known and can be used, see, for example, U.S. Pat. Nos. 5,252,188, 5,397,582, and 7,094,932; and Schandel et al., ChemSusChem 2020, 13, 688. A preferred process is described in commonly assigned U.S. Patent Application No. 63 / 023,763, “Processes for the Pyrolysis of Glycosyltransferases.” "Catalysts for the preparation of C4 aldoses and / or ketones thereof" is described in "Catalysts for the preparation of C4 aldoses and / or ketones thereof" which provide improved yields of glycolaldehyde from the pyrolysis of carbohydrates, from which C4 aldoses and / or ketones can be prepared, generally by condensation reactions, and specifically by condensation reactions using catalysts that include an imidazolate backbone, as specifically described and exemplified herein. Thus, in some embodiments, at least a portion of the glycolaldehyde used in the preparation of C4 aldoses and / or ketones is obtained by the pyrolysis of carbohydrates, such as glucose. In some embodiments, the feed composition includes additional components. For example, compounds such as pyruvaldehyde, formaldehyde, acetol, and glyoxal can be produced by the pyrolysis of carbohydrates. Thus, in various embodiments, the feed composition can further include at least one compound selected from the group consisting of pyruvaldehyde, formaldehyde, acetol, glyoxal, and combinations thereof.

[0018] Carbohydrates can be obtained from a variety of traditional biorenewable sources, such as maize, wheat, potato, cassava, and rice, as well as alternative sources, such as energy crops, plant biomass, agricultural waste, forestry residues, sugar processing residues, and plant-derived domestic waste. In various embodiments, carbohydrates are obtained from grain crops (e.g., corn, wheat, soybeans, rice, barley, rye, millet, sorghum, etc.). More generally, biorenewable sources that can be used include any renewable organic matter that contains a source of carbohydrates, such as, for example, switchgrass, miscanthus, trees (broadleaf and coniferous), vegetation, and crop residues (e.g., bagasse and corn stover). Other sources include, for example, waste materials (e.g., post-consumer paper, food waste, municipal waste, etc.). Carbohydrates can be isolated from biorenewable materials using known methods.

[0019] Carbohydrates obtained from these sources include a variety of monosaccharides, disaccharides, oligosaccharides, and polysaccharides (e.g., C4–C 24 In some embodiments, the carbohydrate comprises at least one sugar selected from the group consisting of monosaccharides, disaccharides, oligosaccharides, and combinations thereof. In various embodiments, the carbohydrate comprises a monosaccharide. The carbohydrate can also comprise cellulose.

[0020] In some embodiments, the carbohydrate comprises a sugar having at least four carbon atoms. For example, the sugar comprises various aldoses. The aldoses referred to herein include various compounds having an aldehyde group and a hydroxyl group, which can be represented by formula (I): HOCH2(HCOH) w CHO (I) where w can be, for example, an integer from 2 to 10, or in some embodiments, an integer from 2 to 5. In various embodiments, the carbohydrate comprises at least one C4-C7 aldose. In some embodiments, the carbohydrate comprises at least one sugar selected from the group consisting of tetrose, pentose, hexose, heptose, and mixtures thereof. Specific C4-C7 aldoses include, for example, threose, erythrose, xylose, ribose, arabinose, glucose, galactose, mannose, glucoheptose, L-glycero-D-manno-heptose, and mixtures thereof. In various embodiments, the carbohydrate comprises a hexose, such as glucose (dextrose). In some embodiments, the carbohydrate comprises a pentose, such as xylose, ribose, and / or arabinose. The term "aldose" and any specific aldose described herein and defined in formula (I) also includes the cyclic forms (hemiacetal forms) of these compounds.

[0021] In some embodiments, the carbohydrate comprises a ketose sugar having at least four carbon atoms. In various embodiments, the carbohydrate comprises at least one ketose sugar selected from the group consisting of ketotetrose, ketopentose, ketohexose, ketoheptose, and mixtures thereof. In some embodiments, the carbohydrate comprises fructose.

[0022] Characteristics of the method Condensation reactions to prepare C4 aldoses and / or their ketones from such feeds can be carried out at temperatures up to 100° C., up to 95° C., up to 90° C., particularly in conjunction with the use of catalysts containing an imidazolate backbone for such purposes. In various embodiments, the reactions are carried out at temperatures above 0° C., above 25° C., above 50° C., or above 80° C. In some embodiments, the reactions are carried out at temperatures between 25° C. and 100° C., between 25° C. and 90° C., between 50° C. and 100° C., between 50° C. and 90° C., between 80° C. and 100° C., or between 80° C. and 90° C.

[0023] Advantageously, the various methods of the present invention do not require caustic conditions in the reaction zone. Surprisingly, it has been found that catalysts containing the imidazolate backbone described herein can be effective under neutral and acidic conditions. Without being bound by theory, it is believed that caustic conditions promote intermolecular reactions such as polymerization and dimerization, as shown in the case of glycolaldehyde below: [ka] Similarly, formaldehyde (another possible component of the feed composition) can form trimer molecules and polymers as shown below. [ka] Surprisingly, it has been found that catalysts containing an imidazolate backbone can be effective under neutral or acidic conditions.

[0024] Under acidic conditions, these dimerized / trimerized / polymerized molecules are likely to exist in their monomolecular form. A process operable under neutral or acidic conditions can advantageously avoid the formation of these compounds and avoid the energy input required to convert these aldehydes back to their original form. Thus, in various embodiments, the reaction is carried out at a pH of 7 or less, 6 or less, or 5 or less. In some embodiments, the reaction is carried out at about neutral pH. In some embodiments, the reaction is carried out without or essentially without added base.

[0025] Furthermore, in various methods of the present invention, there is no need to add chemical additives such as organic solvents for the condensation reaction. Surprisingly, it has been found that catalysts containing imidazolate backbones can be effective without the use of organic solvents. Thus, in various embodiments, the feed composition and / or reaction zone for carrying out the condensation reaction is free or essentially free of organic solvents. In some embodiments, the feed composition and / or reaction zone is free of alcohol solvents. In some embodiments, the feed composition and / or reaction zone is free or essentially free of methanol and / or ethanol. Unless otherwise stated herein, "essentially free" means a concentration of 1% or less, preferably the concentration may be 0.1% or less by weight, or even 0.01% or less by weight, of the chemical components (e.g., feed composition) fed to the reaction zone excluding the catalyst.

[0026] Various methods can provide high conversion of glycolaldehyde during the condensation step. In some embodiments, the conversion of glycolaldehyde is 90% or more, 95% or more, or 99% or more. Various methods of the present invention can provide high conversion of glycolaldehyde in a short reaction time during the condensation to form the desired C4 aldoses and / or ketones. For example, in some embodiments, conversion of glycolaldehyde of 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more is achieved in a reaction time of 10 hours or less, 8 hours or less, 6 hours or less, or 4 hours or less.

[0027] Thus, the methods of the invention are useful for preparing C4 aldoses and / or ketones thereof. In various embodiments, the C4 aldoses and / or ketones thereof comprise at least one compound selected from the group consisting of erythrose, threose, erythrulose, and combinations thereof. In certain embodiments, the C4 aldoses and / or ketones thereof comprise erythrose. In some embodiments, the C4 aldoses and / or ketones thereof comprise threose. In certain embodiments, the C4 aldoses and / or ketones thereof comprise erythrulose.

[0028] Various methods of the invention can provide high selectivity for erythrose, threose, erythrulose, and / or combinations thereof. In some embodiments, the selectivity of the condensation reaction for erythrose, threose, erythrulose, and / or combinations thereof is 80% or more, 85% or more, 90% or more, 93% or more, 95% or more, 97% or more, or 99% or more. In some embodiments, the selectivity of the reaction for a combination of erythrose, threose, and erythrulose is 80% or more, 85% or more, 90% or more, 93% or more, 95% or more, 97% or more, or 99% or more.

[0029] In various embodiments, the selectivity of the condensation reaction towards erythrose is 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 50% or more (e.g., 10%-50%, 10%-40, or 15%-30%).

[0030] In some embodiments, the selectivity of the condensation reaction towards threose is 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 50% or more (e.g., 10% to 50%, 10% to 40, or 15% to 30%).

[0031] In some embodiments, the selectivity of the condensation reaction towards erythrulose is 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 50% or more (e.g., 10% to 50%, 10% to 40, or 15% to 30%).

[0032] Pyrolysis of carbohydrates As described, at least a portion of the glycolaldehyde in the feed composition can be obtained by a pyrolysis process of a carbohydrate. In some embodiments, the process further comprises pyrolyzing a carbohydrate to form glycolaldehyde. In various embodiments, the pyrolysis process comprises pyrolyzing a carbohydrate having at least four carbon atoms in a pyrolysis reaction zone in the presence of water and a pyrolysis catalyst to form a reaction product comprising glycolaldehyde, as contemplated in commonly assigned U.S. Patent Application No. 63 / 023,763, for example. In various embodiments, the pyrolysis catalyst comprises a metal oxide on a catalyst support.

[0033] In general, methods for pyrolysis of carbohydrates can be used to prepare compounds such as glycolaldehyde, methylglyoxal / pyruvaldehyde, acetol / hydroxyacetone, and formaldehyde. As used herein, "carbohydrate" and / or "carbohydrate feed" are understood to include any form of biomass feedstock that contains or forms carbohydrates, particularly carbohydrates having four or more carbon atoms, from which glycolaldehyde can be obtained under pyrolysis conditions.

[0034] It has been found that various pyrolysis methods can produce high yields of glycolaldehyde.Previous attempts to increase the yield of glycolaldehyde have mainly focused on adjusting the feed concentration and reactor conditions, without significantly changing the bed material and / or pyrolysis catalyst.However, it has been surprisingly discovered that certain pyrolysis catalysts (typically, but not necessarily, in the form of a fluidized supported catalyst combined with conventional bed material or material that provides heat transfer to the carbohydrate feed) can significantly affect the pyrolysis reaction and overcome the problems that arise in previous methods.

[0035] In particular, and with reference to the above-referenced commonly-owned, concurrently filed application, it has been found that certain metal oxides are particularly effective in improving the yield of desired products, such as glycolaldehyde, obtained by the pyrolysis of carbohydrates, particularly sugars such as glucose. The pyrolysis methods described herein incorporating these catalysts can advantageously provide improved process economics and reduce the amount of undesirable products that may require separation, special handling, and disposal from the product mixture. For example, pyrolysis methods using these catalysts can allow for more productive use of process inputs (e.g., by requiring less energy), can produce less undesirable by-products, and / or can produce less carbonization in the production of a particular amount of glycolaldehyde and other desired products than would be experienced in the absence of the catalyst. Additionally, the various pyrolysis methods described herein have the advantage of providing stable product yields over long periods of operation and / or at high reactor throughputs.

[0036] Thus, a preferred method for forming C4 aldoses and / or ketones employs an improved pyrolysis process to prepare glycolaldehyde. For example, some embodiments further include preparing glycolaldehyde comprising feeding a feed composition comprising a carbohydrate having at least four carbon atoms to a pyrolysis reaction zone and pyrolyzing the carbohydrate in the pyrolysis reaction zone in the presence of water and a catalyst to form a reaction product comprising glycolaldehyde, the catalyst comprising a metal oxide of a catalyst support.

[0037] Generally, the pyrolysis feed composition comprises carbohydrates having at least four carbon atoms. For example, in some embodiments, the pyrolysis feed composition comprises C4-C 24The carbohydrates may be obtained from a variety of conventional biorenewable sources, as described herein. Other sources include, for example, waste materials (e.g., post-consumer paper, vegetable waste, municipal waste, etc.). The carbohydrates may be isolated from the biorenewable materials using well-known methods. The carbohydrates may be provided in the form of a carbohydrate solution (e.g., an aqueous glucose solution) or as pulverized solids of such biomass.

[0038] Carbohydrates obtained from these sources can include various monosaccharides, disaccharides, oligosaccharides, and polysaccharides as described herein. Carbohydrates can also include cellulose. In some embodiments, carbohydrates include sugars having at least four carbon atoms. For example, sugars can include various aldoses as described herein.

[0039] In some embodiments, the carbohydrate comprises a keto sugar having at least four carbon atoms. In various embodiments, the carbohydrate comprises at least one keto sugar selected from the group consisting of ketotetrose, ketopentose, ketohexose, ketoheptose, and mixtures thereof. In some embodiments, the carbohydrate comprises fructose.

[0040] The pyrolysis feed composition can have a carbohydrate concentration that is 1 wt% or more, 5 wt% or more, 10 wt% or more, 15 wt% or more, or 20 wt% or more. For example, in various embodiments, the feed composition has a carbohydrate concentration that is 1 wt%-50 wt%, 1 wt%-30 wt%, 1 wt%-25 wt%, 5 wt%-50 wt%, 5 wt%-30 wt%, 5 wt%-25 wt%, 10 wt%-50 wt%, 10 wt%-30 wt%, 10 wt%-25 wt%, 15 wt%-50 wt%, 15 wt%-30 wt%, 15 wt%-25 wt%, 20 wt%-50 wt%, 20 wt%-30 wt%, or 20 wt%-25 wt%.

[0041] As described, the preferred pyrolysis method used to produce glycolaldehyde, which can be condensed to obtain C4 aldoses and / or ketones, would be a pyrolysis method carried out in the presence of a catalyst comprising a metal oxide on a catalyst support. In various embodiments, the metal oxide comprises a transition metal oxide. For example, the metal oxide comprises an oxide of a Group 4, 5, 6, 7, 8, 9, 10, or 11 metal, or a mixture thereof. In some embodiments, the metal oxide comprises an oxide of a Group 4, 5, or 6 metal, or a mixture thereof. In some embodiments, the metal oxide comprises an oxide of titanium, molybdenum, tungsten, vanadium, or a mixture thereof. In some embodiments, the metal oxide comprises an oxide of molybdenum, tungsten, vanadium, or a mixture thereof. In some embodiments, the metal oxide comprises an oxide of tungsten, molybdenum, or a mixture thereof. Preferred metal oxides typically include those that preferentially catalyze retro-aldol chemistry.

[0042] Molybdenum and tungsten oxides have been found to be particularly effective in pyrolysis catalysts. Thus, in various embodiments, the metal oxide comprises tungsten oxide. For example, the tungsten oxide can comprise tungsten(IV) oxide and / or tungsten(V) oxide. In some embodiments, the metal oxide comprises molybdenum oxide.

[0043] In some embodiments, tungsten oxide and / or molybdenum oxide constitute a significant portion of the metal oxide in the catalyst support, for example, in some embodiments, tungsten oxide and / or molybdenum oxide constitute at least 1 wt%, at least 2 wt%, at least 3 wt%, at least 4 wt%, at least 5 wt%, at least 10 wt%, at least 15 wt%, at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or at least 99 wt% of the metal oxide in the catalyst support. In various embodiments, the tungsten oxide and / or molybdenum oxide is present in an amount of 1% to 99% by weight, 2% to 99% by weight, 3% to 99% by weight, 4% to 99% by weight, 5% to 99% by weight, 10% to 99% by weight, 15% to 99% by weight, 20% to 99% by weight, 25% to 99% by weight, 30% to 99% by weight, 35% to 99% by weight, 40% to 99% by weight, 45% to 99% by weight, 50% to 99% by weight, 60% to 99% by weight, 70% to 99% by weight, 80% to 99% by weight, 90% to 99% by weight, 95% to 99% by weight, 1 weight Amount%~95wt%, 2wt%~95wt%, 3wt%~95wt%, 4wt%~95wt%, 5wt%~95wt%, 10wt%~95wt%, 15wt%~95wt%, 20wt%~95wt Amount%, 25% to 95% by weight, 30% to 95% by weight, 35% to 95% by weight, 40% to 95% by weight, 45% to 95% by weight, 50% to 95% by weight, 60% to 95% by weight %, 70% to 95% by weight, 80% to 95% by weight, 90% to 95% by weight, 1% to 90% by weight, 2% to 90% by weight, 3% to 90% by weight, 4% to 90% by weight, 5% by weight The metal oxide in the catalyst support constitutes 90% by weight, 10% by weight to 90% by weight, 15% by weight to 90% by weight, 20% by weight to 90% by weight, 25% by weight to 90% by weight, 30% by weight to 90% by weight, 35% by weight to 90% by weight, 40% by weight to 90% by weight, 45% by weight to 90% by weight, 50% by weight to 90% by weight, 60% by weight to 90% by weight, 70% by weight to 90% by weight, or 80% by weight to 90% by weight.In one embodiment, the metal oxide in the catalyst support of the pyrolysis catalyst comprises tungsten oxide and / or molybdenum oxide.

[0044] The pyrolysis catalyst can have a metal oxide loading of 0.1 wt% or more, 0.5 wt% or more, 1 wt% or more, 2 wt% or more, 5 wt% or more, 10 wt% or more, 20 wt% or more, 30 wt% or more, 40 wt% or more, 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, 90 wt% or more, 95 wt% or more, or 99 wt% or more. For example, in various embodiments, the pyrolysis catalyst has a metal oxide loading of 0.1 wt%-15 wt%, 0.5 wt%-15 wt%, 1 wt%-15 wt%, 2 wt%-15 wt%, 5 wt%-15 wt%, 0.1 wt%-10 wt%, 0.5 wt%-10 wt%, 1 wt%-10 wt%, 2 wt%-10 wt%, or 5 wt%-10 wt%.

[0045] In some cases, it has been found that low surface area pyrolysis catalysts and catalyst supports result in greater product yields (e.g., higher yields of glycolaldehyde). Thus, in some embodiments, the pyrolysis catalyst support has a relatively low surface area (e.g., less than 500 m 2 / g or less, 250m 2 / g or less, 100m 2 / g or less, 50m 2 / g or less, 25m 2 / g or less, 10m 2 / g or less, 5m 2 / g or less, or 1m 2 This includes materials having a BET specific surface area of ​​0.1 μm or less (BET specific surface area of ​​0.1 μm or less).

[0046] In various embodiments, the pyrolysis catalyst support comprises a material selected from the group consisting of a glass material, a ceramic material, a refractory material, and mixtures thereof. In some embodiments, the pyrolysis catalyst support comprises a glass material. In certain embodiments, the glass material comprises glass beads (e.g., glass spheres, or similar geometric or amorphous shapes). In some embodiments, the pyrolysis catalyst support comprises a ceramic material selected from the group consisting of silicon carbide, yttria stabilized zirconia, and combinations thereof. In certain embodiments, the pyrolysis catalyst support comprises a material that is substantially non-porous and has a relatively low surface area.

[0047] Long times on stream (TOS) can be achieved with the pyrolysis catalysts described herein and more fully described and exemplified by the commonly owned, co-filed applications we referenced above, in some embodiments the TOS of the catalyst is 1,500 hours or more, 2,000 hours or more, 4,000 hours or more, 6,000 hours or more, 8,000 hours or more, or 10,000 hours or more.

[0048] The pyrolysis catalyst can be prepared by the methods further described herein. In some embodiments, the pyrolysis catalyst comprises a glass material and a coating comprising a metal oxide, the coating being deposited on the coated glass material with a sol-gel comprising the metal oxide or a reaction product thereof. In these and other embodiments, the pyrolysis catalyst is an unfired pyrolysis catalyst.

[0049] Pyrolysis is an energy intensive process that requires high temperatures in the pyrolysis reaction zone, in various embodiments the pyrolysis reaction zone is heated to temperatures of 400° C. or greater, 450° C. or greater, 475° C. or greater, 500° C. or greater, 525° C. or greater, 550° C. or greater, 575° C. or greater, or 600° C. or greater. In some embodiments, the pyrolysis reaction zone is heated to a temperature of 400°C to 600°C, 400°C to 575°C, 400°C to 550°C, 400°C to 525°C, 450°C to 600°C, 450°C to 575°C, 450°C to 550°C, 450°C to 525°C, 500°C to 600°C, 500°C to 575°C, 500°C to 550°C, 500°C to 525°C, 525°C to 600°C, 525°C to 575°C, or 525°C to 550°C.

[0050] In addition to the pyrolysis catalyst comprising a metal oxide on a catalyst support, the pyrolysis reaction zone may further comprise a reaction zone media distinct from the catalyst. In various embodiments, the reaction zone media may comprise any inert material with which the pyrolysis catalyst may be combined and fluidized to provide a generally homogeneously distributed fluidized bed through which the carbohydrate feed composition and pyrolysis products may be carried as they are formed by an inert carrier gas, which may be used to deliver the thermal energy required to pyrolyze the carbohydrates in the carbohydrate feed and convert the carbohydrates into pyrolysis products comprising at least glycolaldehyde. Those skilled in the art will be well able to identify various materials that may be capable of performing these essential functions. In various embodiments, the reaction zone media comprises a material selected from the group consisting of a glass material, a ceramic material, a refractory material, and mixtures thereof. In some embodiments, the reaction zone media comprises a glass material. In some embodiments, the reaction zone media comprises a ceramic material selected from the group consisting of silicon carbide, yttria-stabilized zirconia, and combinations thereof. In some embodiments, the glass material includes glass beads (eg, glass spheres, or similar geometric or amorphous shapes) and / or sand.

[0051] As mentioned above, the reaction zone medium is different from the pyrolysis catalyst, which typically comprises a metal oxide on a support. Thus, in various embodiments, the reaction zone medium is uncoated. In some embodiments, the reaction zone medium is free or essentially free of a metal oxide coating (e.g., less than 1 wt. %, or even less than 0.1 wt. %). In some embodiments, the reaction zone medium comprises a metal oxide-free catalyst support (i.e., a bare pyrolysis catalyst support).

[0052] The pyrolysis catalyst and reaction zone media can comprise the total volume of media packed in the pyrolysis reaction zone, such that the catalyst is 1 vol.% to 50 vol.%, 2 vol.% to 25 vol.%, 3 vol.% to 15 vol.%, or 4 vol.% to 10 vol.% of the total volume of media packed in the pyrolysis reaction zone.

[0053] In various embodiments, the pyrolysis feed composition is fluidized in a fluidizing gas or carrier gas in the pyrolysis reaction zone. The fluidizing gas includes, for example, various inert gases or inert gas mixtures. In some embodiments, the fluidizing gas includes waste gases such as nitrogen, water vapor, carbon dioxide, and / or combustion off gas. In some embodiments, for example, when the carbohydrates are provided in the form of a carbohydrate solution, the pyrolysis method further includes atomizing the feed composition provided to the pyrolysis reaction zone. In some embodiments, the pyrolysis feed composition can be atomized using a fluidizing gas (e.g., nitrogen, steam, etc.).

[0054] The average residence time of the carbohydrate feed in the pyrolysis reaction zone may be relatively fast. For example, in some embodiments, the residence time is 10 seconds or less, 8 seconds or less, 6 seconds or less, 4 seconds or less, 2 seconds or less, 1 second or less, or 0.5 seconds or less. In some embodiments, the residence time is 0.5 seconds to 10, 0.5 seconds to 5 seconds, 0.5 seconds to 2 seconds, 0.5 seconds to 1 second, 1 second to 10, 1 second to 5 seconds, or 1 second to 2 seconds.

[0055] In general, the pyrolysis reaction zone can include one or more batch, semi-batch, or continuous reactor designs using fixed bed reactors, trickle bed reactors, slurry phase reactors, moving bed reactors, or any other design that allows catalytic reactions, particularly heterogeneous catalytic reactions. Examples of reactors can be found in Chemical Process Equipment-Selection and Design, Couper et al., Elsevier 1990, which is incorporated herein by reference. In various processes described herein, the pyrolysis reaction zone includes one or more fluidized bed reactors. It should be understood that the feed composition, any fluidizing gas, and catalyst can be introduced into the appropriate reactor separately or in various combinations.

[0056] It has been found that the improved pyrolysis methods summarized herein can enhance product yields. For example, as demonstrated herein using a 20 wt. % aqueous glucose solution as the carbohydrate feed, the various pyrolysis methods described herein provide glycolaldehyde yields of 70% or more, 75% or more, or 80% or more. In some embodiments, the glycolaldehyde yield is 70%-85%, 70%-80%, 75%-85%, or 75%-80%.

[0057] The pyrolysis reaction product may further comprise other minor components. In various embodiments, the pyrolysis reaction product comprises at least one other component selected from the group consisting of formaldehyde, glyoxal, pyruvaldehyde, acetol, and mixtures thereof. In some embodiments, the pyrolysis reaction product further comprises formaldehyde. In some embodiments, the pyrolysis reaction product further comprises formaldehyde, and the molar ratio of glycolaldehyde to formaldehyde is 5:1 or greater, 6:1 or greater, 8:1 or greater, 10:1 or greater, or 12:1 or greater.

[0058] In various embodiments, the pyrolysis reaction product further comprises glyoxal, hi some embodiments, the pyrolysis reaction product further comprises glyoxal, and the molar ratio of glycolaldehyde to glyoxal is 10:1 or greater, 15:1 or greater, 20:1 or greater, or 25:1 or greater.

[0059] In various embodiments, the pyrolysis reaction product further comprises pyruvaldehyde, hi some embodiments, the pyrolysis reaction product further comprises pyruvaldehyde, and the molar ratio of glycolaldehyde to pyruvaldehyde is 5:1 or greater, 6:1 or greater, 8:1 or greater, 10:1 or greater, or 12:1 or greater.

[0060] In various embodiments, the pyrolysis reaction product further comprises acetol, hi some embodiments, the pyrolysis reaction product further comprises acetol, and the molar ratio of glycolaldehyde to acetol is 15:1 or greater, 20:1 or greater, 25:1 or greater, or 30:1 or greater.

[0061] In various embodiments, the pyrolysis reaction product is free or essentially free of ethylene glycol, hi some embodiments, the molar ratio of glycolaldehyde to ethylene glycol in the pyrolysis reaction product is 100:1 or greater; 200:1 or greater; or 400:1 or greater.

[0062] Thus, the methods of the invention for forming C4 aldoses and / or ketones can include various combinations of the features described herein. For example, various methods include: providing a feed composition comprising a carbohydrate having at least four carbon atoms to a pyrolysis reaction zone; Pyrolyzing a carbohydrate in the presence of water and a catalyst in a pyrolysis reaction zone to form a reaction product comprising glycolaldehyde, the catalyst comprising a metal oxide on a catalyst support, and reacting the carbohydrate under the following conditions: (a) The pyrolysis reaction zone is heated to a temperature of 400°C or greater; (b) The catalyst support is 500m 2 / g or less, 250m 2 / g or less, 100m2 / g or less, 50m 2 / g or less, 25m 2 / g or less, 10m 2 / g or less, 5m 2 / g or less, or 1m 2 / g or less BET specific surface area; (c) the catalyst support comprises a glass material; (d) the pyrolysis reaction zone further comprises a reaction zone medium distinct from the catalyst; and / or (e) the yield of glycolaldehyde is 70% or more, 75% or more, or 80% or more; At least one of the following is satisfied: The method may further include preparing glycolaldehyde by a process comprising:

[0063] Pyrolysis catalysts can be prepared by a variety of techniques. Metal oxides can be deposited on catalyst supports using procedures such as, but not limited to, sol-gel, incipient wetness, ion-exchange, deposition-precipitation, and vacuum impregnation techniques.

[0064] One method for preparing pyrolysis catalysts that has proven particularly effective is: mixing a metal oxide, a solvent, and a strong acid to form a sol-gel; depositing the sol-gel onto a pyrolysis catalyst support to form a coated catalyst support; removing the solvent from the coated catalyst support to form a pyrolysis catalyst; Includes.

[0065] In some embodiments, the sol-gel is prepared by mixing a metal oxide, a peroxide source, and a solvent, hi further embodiments, the peroxide source comprises hydrogen peroxide and the solvent comprises water.

[0066] The metal oxide, metal oxide filler, and support can be any of those identified herein for the pyrolysis catalyst. For example, in some embodiments, the metal oxide can include tungsten oxide and / or molybdenum oxide, and the support can include a low surface area material such as glass (e.g., glass beads).

[0067] In various embodiments, the solvent is selected from the group consisting of C1-C 10 Contains alkanols, e.g., C1-C 10 The alkanol is selected from the group consisting of isopropanol, ethanol, and mixtures thereof. Additionally, the strong acid can be selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, and mixtures thereof.

[0068] The sol-gel may be formed in air or in an inert atmosphere. In some embodiments, the sol-gel is formed in an inert atmosphere. For example, the sol-gel may be formed in a nitrogen atmosphere. Additionally, the sol-gel may be formed in the substantial absence of oxygen. In various embodiments, the sol-gel may be prepared by mixing a metal oxide, a peroxide source, and a solvent. In some embodiments, the peroxide source may be hydrogen peroxide and the solvent may be water.

[0069] During solvent removal, the coated catalyst support can be heated to a temperature sufficient to evaporate any solvent in the coated catalyst. In various embodiments, the coated catalyst support is heated to a temperature of 80° C. or more, 90° C. or more, or 100° C. or more to remove the solvent. However, in various embodiments, the catalyst is not exposed to temperatures typical of calcination (e.g., 500° C. or more, 750° C. or more, or 1000° C. or more).

[0070] Downstream Process The methods of the present invention also include integrated processes that include an additional step of converting C4 aldoses and / or their ketones to downstream products. For example, various methods are directed to the preparation of erythritol and / or threitol. In some embodiments, these methods include preparing erythrose and / or threose by the condensation methods described herein (e.g., contacting a feed composition containing glycolaldehyde with a catalyst containing an imidazolate backbone in a reaction zone to condense at least a portion of the glycolaldehyde to obtain erythrose and threose); and hydrogenating at least a portion of the erythrose and / or threose to form erythritol and / or threitol. Suitable methods for hydrogenating erythrose and threose to form erythritol and threitol, respectively, are well known to those skilled in the art, see, for example, U.S. Pat. Nos. 4,487,980 and 6,300,494, all of which are incorporated herein by reference. One preferred method for forming these sugar alcohols is described in commonly assigned U.S. Pat. No. 10,196,333 to Werpy et al., entitled "Multiphase Low Mixing Processes," which is incorporated herein by reference.

[0071] Another method is directed to the preparation of erythronic acid, threonic acid, and / or salts thereof. In various embodiments, these methods include preparing erythrose and / or threose by the condensation methods described herein (e.g., contacting a feed composition comprising glycolaldehyde with a catalyst comprising an imidazolate backbone in a reaction zone to condense at least a portion of the glycolaldehyde to obtain erythrose and threose); and oxidizing at least a portion of the erythrose and / or threose to form erythronic acid, threonic acid, and / or salts thereof. Suitable methods for the oxidation of erythrose and / or threose are also known, see, for example, U.S. Patent Application Publication No. 2007 / 0027341.

[0072] Further integrated processes are directed to the preparation of downstream products such as glyceraldehyde; methyl vinyl glycolate; 2-hydroxy-4-methoxybutanoate; 2-hydroxy-4-methoxybutanoic acid; 1,4-butandiol; α-hydroxy-γ-butyrolactone, methionine, and analogs thereof. In some embodiments, these methods include preparing a C4 aldose and / or ketone thereof by the methods described herein (e.g., contacting a feed composition comprising glycolaldehyde with a catalyst comprising an imidazolate backbone in a reaction zone to condense at least a portion of the glycolaldehyde to obtain a C4 aldose and / or ketone thereof); and converting the C4 aldose and / or ketone thereof to a downstream product or a precursor thereof, the downstream product being a compound selected from the group consisting of glyceraldehyde; methyl vinyl glycolate; 2-hydroxy-4-methoxybutanoate; 2-hydroxy-4-methoxybutanoic acid; 1,4-butanediol; α-hydroxy-γ-butyrolactone, methionine, and analogs thereof. Methods for forming each of these downstream products or their precursors from C4 aldoses and / or their ketones are already known, see for example Holm et al., Green Chemistry (2012) 14, pp 702-706 (methyl vinyl glycolate; 2-hydroxy-4-methoxybutanoate; and 2-hydroxy-4-methoxybutanoic acid); Amada et al., (2012), ChemSusChem, 5: 1991-1999 (1,4-butanediol); Dusselier et al, ACS Catal., 2013, 3 (8), pp 1786-1800 (α-hydroxy-γ-butyrolactone); U.S. Pat. No. 10,189,778 (methionine), all of which are incorporated herein by reference.

[0073] Generally, the reaction zone may comprise one or more batch, semi-batch, or continuous reactor designs using fixed bed reactors, trickle bed reactors, slurry phase reactors, moving bed reactors, fluidized bed reactors, or any other design capable of catalytic reactions, particularly heterogeneously catalyzed reactions. Examples of such reactors can be found in Chemical Process Equipment - Selection and Design, Couper et al., Elsevier 1990, incorporated herein by reference.

[0074] Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention as defined in the appended claims. It is therefore intended that all matter contained in the above description or in the specific examples given below should be interpreted as illustrative and not in a limiting sense.

[0075] When introducing elements of the invention or preferred embodiments thereof, the articles "a," "an," "the," and "said" are intended to mean that there are one or more elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0076] More specifically, as used herein, the term "comprising" is to be understood to encompass the option that the product / method / use in relation to which the term "comprising" is used may "consist only of" the elements set forth below.

[0077] Also, as used herein, the term "comprising" should be understood to similarly encompass the options that the product / method / use in relation to which the term "comprising" is used may "consist essentially of" the elements set forth below.

[0078] Unless otherwise specified, it should be understood that all synthetic procedures and parameter measurements were conducted at room / ambient temperature, i.e., 21±1 degrees Celsius. EXAMPLES

[0079] The following examples are provided to further and more particularly illustrate the present invention.

[0080] Example 1: Preparation of metal oxide coated glass bead catalyst To prepare the metal oxide coated glass bead catalysts, the metal oxide sol-gel was first prepared in a nitrogen filled environment to prevent exposure to oxygen. 0.70 mL of tungsten(V) ethoxide, 1,2-dimethoxyethane adduct, 99% was added to 50 mL of isopropanol with stirring. 0.2 mL of 2 M hydrochloric acid was then added dropwise, resulting in a pale yellow sol with a white precipitate. The mixture was stirred at room temperature for approximately 1 hour and left overnight.

[0081] Glass beads were prepared by fumigating glass beads with isopropanol. 25 ml of the fumigated glass beads were then added to the sol. The mixture containing the glass beads was mixed periodically and left uncovered. The resulting coated glass beads were uniformly coated with the tungsten oxide solution.

[0082] The coated glass beads were then dried at ambient temperature and heated overnight at about 80° C. The coated glass beads were not subjected to calcination or other modification.

[0083] Each coated glass bead contained approximately 0.25% by weight tungsten in the form of a thin film coating.

[0084] Example 2: Preparation of metal oxide coated glass bead catalyst The experiment was carried out according to the procedure of Example 1, except that the coated glass beads were rinsed with acetone before being heated overnight at about 80° C. Rinsing the coated glass beads with acetone did not remove any significant amount of the tungsten oxide solution.

[0085] Example 3: Thermal decomposition of dextrose using glass bead catalyst The untreated glass bead catalyst was tested for the thermal decomposition of dextrose utilizing a fluidized bed reactor system. The glass bead catalyst comprised 6% of the total media volume of the reactor bed. Approximately 20% by weight of dextrose solution was introduced into the reactor system at a rate of 1.7 mL / min. A nitrogen gas stream was also introduced into the system at a rate of 4500-5000 mL / min. Tables 1-3 below report the product profiles at various times during the flow for various reaction temperatures. The residence time for each reaction shown below was 0.98 seconds.

[0086] [Table 1]

[0087] [Table 2]

[0088] [Table 3]

[0089] Example 4: Pyrolysis of dextrose using tungsten carbide Tungsten carbide grit material was mixed with glass beads and utilized in a fluidized bed reactor system for the pyrolysis or cracking of dextrose. The mixture was tested at various reactor temperatures and compared to experiments performed with uncoated glass beads.

[0090] A dextrose solution of about 20 wt. % was introduced into the reactor system at a rate of 1.7 mL / min. A stream of nitrogen gas was also introduced into the system at a rate of 4500-5000 mL / min. Tables 4 and 5 show the temperatures, flow rates, residence times, etc. at various locations in the reactor system. The "bottom temperature" reported below is the temperature at the feed nozzle of the fluidized bed reactor. Table 6 shows the product profile at specific times during the run.

[0091] [Table 4]

[0092] [Table 5]

[0093] [Table 6]

[0094] A second experiment utilizing tungsten carbide grit material mixed with glass beads was conducted under the same conditions. The cracking media contained approximately 3% tungsten carbide grit and 97% glass beads by volume. Tables 7 and 8 show the temperatures, flow rates, residence times, etc. at various locations in the reactor system. The product profile for this second experiment is shown in Table 9.

[0095] [Table 7]

[0096] [Table 8]

[0097] [Table 9]

[0098] Example 5: Thermal decomposition of dextrose using tungsten oxide coated glass beads catalyst Several experiments similar to those conducted in Example 4 were conducted. Tables 10 and 11 show the results of using a tungsten oxide coated glass bead catalyst at various temperatures in a reactor system, where the tungsten oxide coated catalyst comprised approximately 6% by weight of the total cracking media.

[0099] [Table 10]

[0100] [Table 11]

[0101] As demonstrated by the results above, the catalysts comprising metal oxide coated glass beads produced significantly higher yields of glycolaldehyde compared to the metal carbide catalysts.

[0102] Example 6: Thermal decomposition of dextrose using molybdenum oxide coated glass beads catalyst A similar experiment to Example 4 was carried out using a molybdenum oxide coated glass bead catalyst, which accounted for about 6% by weight of the total cracking media. The catalyst was tested at various reactor temperatures. The reaction conditions are shown in Table 12 and the results are shown in Table 13.

[0103] [Table 12]

[0104] [Table 13]

[0105] Example 7: Thermal decomposition of dextrose using vanadium oxide coated glass beads catalyst A similar experiment to Example 4 was carried out using a glass bead catalyst coated with 5 wt. % vanadium oxide. This catalyst was used in a reaction at a set temperature of 525° C. After 50 hours on stream, coking of the reactor was observed.

[0106] The reaction conditions are listed in Table 14 below. Table 15 shows the temperatures at various locations in the reactor during the reaction. The "bottom temperature" below is the temperature at the feed nozzle. Table 16 shows the production profile of the reaction products.

[0107] [Table 14]

[0108] [Table 15]

[0109] [Table 16]

[0110] Example 8: Pyrolysis of dextrose using molybdenum-coated quartz sand catalyst An experiment similar to Example 4 was conducted using a cracking media that was approximately 5 wt. % molybdenum coated quartz sand catalyst and 95 wt. % untreated quartz sand. The reaction was conducted at a set temperature of 525° C. The reaction conditions are listed below in Tables 17 and 18. The "bottom temperature" reported below is the temperature at the feed nozzle. Table 19 shows the results of the experiment.

[0111] After 3 hours on stream, the reaction was stopped and the reactor was inspected: coking was observed and solid lumps had formed in the reactor.

[0112] [Table 17]

[0113] [Table 18]

[0114] [Table 19]

[0115] Example 9: Pyrolysis of dextrose using titania-coated glass beads catalyst Titania oxide coated glass beads were prepared according to the procedure of Example 1, and the thermal decomposition of dextrose using this catalyst was tested according to the procedure of Example 4. The reaction product profile is shown in Table 20 below.

[0116] The entire reactor body and all gas handling lines were properly cleaned prior to running the reaction. The reactor was unable to operate for more than 30 hours before being completely sealed. Investigation revealed that a solid mass had formed within the reactor and the gas handling lines had become sealed with a mixture of char and pyrolysis oil. It was hypothesized that after injection, the feed reacted with the glass beads to form a solid mass, increasing the amount of char. This buildup eventually caused the reactor to shut down and pressure to increase.

[0117] [Table 20]

[0118] Example 10: Preparation of ZIF-4 catalyst 3.641 g of zinc nitrate hexahydrate and 2.40 g of imidazole were combined in a flask. 240 ml of N,N-dimethylformamide was added and a reflux condenser was attached to the flask outlet. The contents were heated at approximately 130° C. for 48 hours while stirring at low speed with a stir bar. Upon application of heat, the solids readily dissolved to form a clear solution. As the reaction proceeded, a white precipitate was observed. The precipitate was then washed with water and dried under reduced pressure to form the ZIF-4 catalyst.

[0119] Example 11: Testing of various catalysts for the conversion of glycolaldehyde Various catalysts were tested for their ability to condense at least a portion of glycolaldehyde to produce threose, erythrose, and / or erythrulose. In this experiment, calcium-type ion exchange resin (PCR560 Ca), commercially available zeolite Linde Type-A zeolite (Sigma Aldrich product number #96096), commercially available zeolite acid-treated with hydrochloric acid (Sigma Aldrich product number #96096), calcium hydroxide, and the ZIF-4 catalyst of Example 10 were tested.

[0120] Approximately 40 mg of each catalyst was added to 2 ml of diluted pyrolysate (containing approximately 5.8 wt. % glycolaldehyde). Evaluations were performed at 1 and 2 hours for each catalyst. Samples were analyzed using HPLC to determine the amount of glycolaldehyde consumed based on the mole percent of the starting pyrolysate material and to evaluate the spectrum of desired products. The results are shown in Table 21 below.

[0121] [Table 21]

[0122] Screening of these compounds showed that the ZIF-4 catalyst outperformed the other catalysts at both the 1 and 2 hour time points in terms of forming the desired product.

[0123] To verify the results, additional experiments were performed using ZIF-4 catalyst. The results for ZIF-4 catalyst are shown in Table 22 below. These results are normalized to threose and erythrulose alone.

[0124] [Table 22]

[0125] Example 12: Testing of ZIF-4 catalyst for conversion of glycolaldehyde The experiment of Example 11 was repeated with a second ZIF-4 catalyst and 5.4 wt% glycolaldehyde solution. Sampling and analysis of the reaction mixture was performed at 2 hours, 4 hours, and 6 hours. Similar yields of threose, erythrose, and erythrulose were obtained compared to those reported in Example 12 for the conversion of pyrolysis products. The results are shown in Table 23 below.

[0126] [Table 23]

[0127] In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

[0128] item: 1. A process for preparing C4 aldoses and / or ketones thereof, comprising: A process comprising contacting a feed composition comprising glycolaldehyde with a catalyst comprising an imidazolate backbone in a reaction zone to condense at least a portion of the glycolaldehyde to obtain a C4 aldose and / or ketone thereof.

[0129] 2. A method for preparing C4 aldoses and / or ketones thereof, comprising the steps of: providing a feed composition comprising a carbohydrate having at least four carbon atoms to a pyrolysis reaction zone; Pyrolyzing a carbohydrate in the presence of water and a catalyst in a pyrolysis reaction zone to form a reaction product comprising glycolaldehyde, the catalyst comprising a metal oxide on a catalyst support, and reacting the carbohydrate under the following conditions: (a) The pyrolysis reaction zone is heated to a temperature of 400°C or greater; (b) The catalyst support is 500m 2 / g or less, 250m 2 / g or less, 100m 2 / g or less, 50m 2 / g or less, 25m 2 / g or less, 10m 2 / g or less, 5m 2 / g or less, or 1m 2 / g or less BET specific surface area; (c) the catalyst support comprises a glass, a ceramic, or a refractory material; (d) the pyrolysis reaction zone further comprises a reaction zone medium distinct from the catalyst; and / or (e) the yield of glycolaldehyde is 70% or more, 75% or more, or 80% or more; At least one of the following is satisfied; condensing glycolaldehyde in or from the reaction product thus formed to obtain C4 aldoses and / or ketones thereof from glycolaldehyde; A method comprising:

[0130] 3. The method of item 2, wherein the condensation of glycolaldehyde in or from the reaction product comprises contacting the reaction product or a portion thereof containing glycolaldehyde with a catalyst containing an imidazolate backbone in a reaction zone to condense at least a portion of the glycolaldehyde to obtain a C4 aldose and / or a ketone thereof.

[0131] 4. The method of item 1, wherein the feed composition comprises glycolaldehyde in a concentration by weight of 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, or 70% or more.

[0132] 5. The method of claim 1, wherein the feed composition comprises a glycolaldehyde concentration of 1% to 70% by weight, 1% to 50% by weight, 1% to 25% by weight, or 1% to 10% by weight.

[0133] 6. The method of any one of items 1, 4, or 5, wherein the feed composition further comprises at least one compound selected from the group consisting of pyruvaldehyde, formaldehyde, acetol, glyoxal, and combinations thereof.

[0134] 7. The method of claim 5, wherein the feed composition further comprises water.

[0135] 8. The method of any one of items 1 to 7, wherein the C4 aldose and / or ketone thereof comprises at least one compound selected from the group consisting of erythrose, threose, erythrulose, and combinations thereof.

[0136] 9. The method of any one of items 1 to 8, wherein the C4 aldose and / or ketone thereof comprises erythrose.

[0137] 10. The process of any one of items 1 to 9, wherein the C4 aldose and / or ketone thereof comprises threose.

[0138] 11. The method of any one of items 1 to 10, wherein the C4 aldose and / or ketone thereof comprises erythrulose.

[0139] 12. The method of any one of items 1 or 3-11, wherein the imidazolate backbone comprises one or more metals and / or metalloids.

[0140] 13. The method of claim 12, wherein the imidazolate framework comprises one or more metals and / or metalloids selected from the group consisting of zinc, cobalt, copper, iron, lithium, boron, and combinations thereof.

[0141] 14. The method of claim 13, wherein the imidazolate skeleton contains zinc.

[0142] 15. The method of claim 13, wherein the catalyst comprises a zeolitic imidazolate framework (ZIF).

[0143] 16. The method of claim 13, wherein the catalyst comprises a boron imidazolate framework (BIF).

[0144] 17. The method of claim 13, wherein the imidazolate scaffold is selected from the group consisting of ZIF-4, ZIF-8, ZIF-14, BIF-2Li, BIF-2Cu, BIF-5, and combinations thereof.

[0145] 18. The method of claim 17, wherein the imidazolate scaffold comprises ZIF-4.

[0146] 19. The process of item 18, wherein the catalyst consists of, or consists essentially of, ZIF-4.

[0147] 20. The process of any one of items 12 to 19, wherein the imidazolate framework and / or catalyst is free or essentially free of tin, zirconia, and / or silica.

[0148] 21. The process of any one of items 1 to 20, wherein the condensation reaction is carried out at a temperature of 100°C or less, 95°C or less, or 90°C or less.

[0149] 22. The process according to any one of items 1 to 21, wherein the condensation reaction is carried out at a temperature of 0°C or higher, 25°C or higher, 50°C or higher, or 80°C or higher.

[0150] 23. The process according to any one of items 1 to 22, wherein the condensation reaction is carried out at a temperature of 25°C to 100°C, 25°C to 90°C, 50°C to 100°C, 50°C to 90°C, 80°C to 100°C, or 80°C to 90°C.

[0151] 24. The method according to any one of items 1 to 23, wherein the conversion rate of glycolaldehyde in the condensation reaction is 90% or more, 95% or more, or 99% or more.

[0152] 25. The process of any one of items 1 to 24, wherein a conversion rate of glycolaldehyde of 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more is achieved in a reaction time of 10 hours or less, 8 hours or less, 6 hours or less, or 4 hours or less.

[0153] 26. The process of any one of items 1 to 25, wherein the selectivity of the condensation reaction towards erythrose, threose, erythrulose, and / or combinations thereof is 80% or more, 85% or more, 90% or more, 93% or more, 95% or more, 97% or more, or 99% or more.

[0154] 27. The method according to any one of items 1 to 26, wherein the selectivity of the condensation reaction for a combination of erythrose, threose, and erythrulose is 80% or more, 85% or more, 90% or more, 93% or more, 95% or more, 97% or more, or 99% or more.

[0155] 28. The method according to any one of items 1 to 27, wherein the selectivity of the condensation reaction towards erythrose is 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 50% or more.

[0156] 29. The process according to any one of items 1 to 28, wherein the selectivity of the condensation reaction towards threose is 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 50% or more.

[0157] 30. The method according to any one of items 1 to 29, wherein the selectivity of the condensation reaction towards erythrulose is 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, 40% or more, or 50% or more.

[0158] 31. The method of any one of items 1 to 30, wherein the condensation reaction is carried out at a pH of 7 or less, 6 or less, or 5 or less.

[0159] 32. The method of any one of items 1 to 31, wherein the condensation reaction is carried out at about neutral pH.

[0160] 33. The process of any one of items 1 to 32, wherein the condensation reaction is carried out in the absence or essentially absence of added base.

[0161] 34. The process of any one of items 1 to 33, wherein the feed composition for the condensation reaction and / or the reaction zone is free or essentially free of alcohol solvents.

[0162] 35. The process of any one of items 1 to 34, wherein the feed composition for the condensation reaction and / or the reaction zone is free or essentially free of methanol and / or ethanol.

[0163] 36. The process of any one of items 1 to 35, wherein the feed composition for the condensation reaction and / or the reaction zone is free or essentially free of organic solvents.

[0164] 37. The method of any one of items 1 or 3 to 36, wherein the imidazolate scaffold is prepared from a precursor comprising an imidazole and / or an imidazole-type compound and a metal salt.

[0165] 38. The method of any one of items 1 or 3 to 37, wherein the imidazolate scaffold is prepared from a precursor comprising imidazole and zinc nitrate hexahydrate.

[0166] 39. The process of any one of items 1 or 3 to 38, wherein the reaction zone is free or essentially free of pentasil zeolite.

[0167] 40. A method for preparing erythritol and / or threitol, comprising the steps of: 40. A process comprising: preparing erythrose and / or threose by the process of any one of claims 1 to 39; and hydrogenating at least a portion of the erythrose and / or threose to form erythritol and / or threitol.

[0168] 41. A method for preparing erythronic acid, threonic acid, and / or salts thereof, comprising: Preparing erythrose and / or threose by the method of any one of claims 1 to 39; oxidizing at least a portion of erythrose and / or threose to form erythronic acid, threonic acid, and / or salts thereof; A method comprising:

[0169] 42. A method for preparing a downstream product, comprising: Preparing a C4 aldose and / or a ketone thereof by the method of any one of claims 1 to 39; and converting the C4 aldose and / or ketone thereof to a downstream product or a precursor thereof, wherein the downstream product is a compound selected from the group consisting of glyceraldehyde; methyl vinyl glycolate; 2-hydroxy-4-methoxybutanoate; 2-hydroxy-4-methoxybutanoic acid; 1,4-butandiol; α-hydroxy-γ-butyrolactone, methionine, and analogs thereof.

[0170] 43. The method of item 1, wherein at least a portion of the glycolaldehyde is obtained from pyrolysis of a carbohydrate.

[0171] 44. The method of claim 43, wherein at least a portion of the glycolaldehyde is obtained from the pyrolysis of a sugar.

[0172] 45. At least a portion of the glycolaldehyde is 45. The process of claim 44, comprising pyrolyzing a carbohydrate having at least four carbon atoms in a pyrolysis reaction zone in the presence of water and a pyrolysis catalyst to form a reaction product comprising glycolaldehyde, wherein the pyrolysis catalyst comprises a metal oxide on a catalyst support.

Claims

1. C ４ 1. A process for preparing aldoses and / or ketones thereof comprising the steps of: A feed composition comprising glycolaldehyde is contacted with a catalyst comprising an imidazolate backbone in a reaction zone to condense at least a portion of said glycolaldehyde to produce said C ４ obtaining aldoses and / or ketones thereof, The method of claim 1, wherein the imidazolate framework comprises one or more metals and / or metalloids selected from the group consisting of zinc, cobalt, copper, iron, lithium, boron, and combinations thereof.

2. C ４ 1. A process for preparing aldoses and / or ketones thereof comprising the steps of: providing a feed composition comprising a carbohydrate having at least four carbon atoms to a pyrolysis reaction zone; pyrolyzing the carbohydrate in the presence of water and a catalyst in the pyrolysis reaction zone to form a reaction product comprising glycolaldehyde, the catalyst comprising a metal oxide on a catalyst support and reacting under the following conditions: (a) the pyrolysis reaction zone is heated to a temperature of 400° C. or greater; (b) The catalyst carrier is 500 m ２ / g or less BET specific surface area; (c) the catalyst support comprises a glass, ceramic, or refractory material; (d) the pyrolysis reaction zone further comprises a reaction zone medium distinct from the catalyst; and / or (e) the yield of glycolaldehyde is 70% or more; and at least one of the following is satisfied; In the reaction product thus formed or from the reaction product, glycolaldehyde is condensed to give C ４ obtaining aldoses and / or ketones thereof; Including, said condensing said glycolaldehyde in or from said reaction product comprises contacting said reaction product or a portion thereof comprising glycolaldehyde with a catalyst comprising an imidazolate backbone in a reaction zone to condense at least a portion of said glycolaldehyde to obtain said C4 aldose and / or ketone thereof; The method of claim 1, wherein the imidazolate framework comprises one or more metals and / or metalloids selected from the group consisting of zinc, cobalt, copper, iron, lithium, boron, and combinations thereof.

3. 10. The method of claim 1, wherein the feed composition comprises glycolaldehyde at a concentration of 1% by weight or greater.

4. 3. The method of claim 1 or 2, wherein the feed composition further comprises at least one compound selected from the group consisting of pyruvaldehyde, formaldehyde, acetol, glyoxal, and combinations thereof.

5. The method of claim 4 , wherein the feed composition further comprises water.

6. Said C ４ 3. The method of claim 1 or 2, wherein the aldose and / or ketone thereof comprises at least one compound selected from the group consisting of erythrose, threose, erythrulose, and combinations thereof.

7. 3. The method of claim 1 or 2, wherein the imidazolate backbone is selected from the group consisting of ZIF-4, ZIF-8, ZIF-14, BIF-2Li, BIF-2Cu, BIF-5, and combinations thereof.

8. The method of claim 7, wherein the imidazolate backbone comprises ZIF-4.

9. 9. The method of any one of claims 1, 2, 7 and 8, wherein the imidazolate framework and / or the catalyst is free of or contains less than 1% of tin, zirconia and / or silica.

10. 3. The process according to claim 1 or 2, wherein the condensation reaction is carried out at a temperature below 100°C.

11. 3. The method of claim 1 or 2, wherein the condensation reaction is carried out at a temperature of 0° C. or higher.

12. 3. The method of claim 1 or 2, wherein the condensation reaction is carried out at a pH of 7 or less.

13. 13. The method of claim 12, wherein the condensation reaction is carried out without or with 1% or less of added base.

14. 3. The method of claim 1 or 2, wherein the feed composition for the condensation reaction and / or the reaction zone is free of alcohol solvent or contains 1% or less of alcohol solvent.

15. 3. The method of claim 1 or 2, wherein the feed composition for the condensation reaction and / or the reaction zone contains no or less than 1% organic solvent.

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