JP5788905B2 - Sugar isomerization - Google Patents

Description

[Cross-reference of related applications]
This application is filed on Jan. 15, 2010 under 35 USC 119 (e), pending US provisional application 61 / 295,637, “Catalysts for the Isomerization of Sugars”, 2010. Pending US Provisional Application No. 61 / 305,480, “Catalysts for the Isomerization of Sugars”, filed February 17, 2010, pending US Provisional Application No. 61 No. 359,782, “New Catalysts for the Isomerization of Sugars” and pending US Provisional Application No. 61 / 421,840, filed Dec. 10, 2010, “New Catalysts for the Isomerization of Sugars” Claim priority based on. These applications are incorporated herein in their entirety.

  Under 35 USC 202 (c), the US Government has certain rights to the invention described herein. This invention was partially completed with funding from the US Department of Energy Science Department Basic Energy Science, Award number DE-SC0001004.

  The present invention belongs to the field of sugar isomerization.

  In view of the desirability of using renewable raw materials such as biomass, the importance of carbohydrate-based chemical processes has increased. Sugar isomerization is an important class of reactions used in various industrial carbohydrate-based processes. Of particular importance among such reactions is the conversion of glucose to fructose. This reaction has been used to produce high fructose corn syrup (HFCS) and valuable chemical intermediates such as 5-hydroxymethylfurfural (HMF) and levulinic acid.

  The isomerization of glucose to fructose can be carried out under mild conditions using biological or chemical catalysts. The reaction is slightly endothermic (H = 3 kJ / mol) and reversible (Keq at 298K is ˜1). This means that the maximum rate of conversion of glucose to fructose is governed by the thermodynamic equilibrium between both sugars at the reaction temperature.

  Industrial glucose isomerization is usually carried out using immobilized enzymes, and thus has the advantage of high conversion and selectivity, but also has a number of disadvantages. Enzymatic catalysts do not sustain high activity over multiple cycles, cannot be easily regenerated, and do not function through a wide variety of temperatures, pH, salt concentrations, and other processing conditions. Furthermore, enzyme isomerization catalysts are not easily incorporated into upstream processes that produce glucose from biomass, or are easily incorporated into downstream processes that convert fructose into other chemical intermediates.

For example, one suitable industrial isomerization method produces an equilibrium mixture of fructose 42% (wt / wt), glucose 50% (wt / wt), and other sugars 8% (wt / wt) at 333K. This method uses an immobilized enzyme (xylose isomerase). Such enzymatic processes have high fructose yields but have various disadvantages including: (i) various pre-reaction purification steps to remove impurities that strongly inhibit enzyme activity from the raw material. (Ii) to maintain an optimum pH of 7.0-8.0, which is necessary (e.g., calcium ions from the previous starch liquefaction / saccharification step need to be removed to a level of less than 1 ppm) Buffer solution (Na ₂ CO ₃ ), enzyme-activating buffer solution (MgSO ₄ ) requires ion exchange after reaction, (iii) Maximizes both product yield and enzyme lifetime Since the optimum working temperature is 333 K, it is difficult to further increase the reaction rate at a higher temperature. (Iv) The catalytic activity is periodically changed because the enzyme activity gradually deteriorates irreversibly. In, it is relatively high operating costs.

  Accordingly, it is desirable to provide a method for sugar isomerization that has high conversion efficiency and selectivity and does not have the disadvantages associated with enzyme catalysis.

  In order to overcome the above-mentioned problems, the method disclosed herein comprises contacting a monosaccharide with a high silica zeolite containing tin or titanium incorporated in a zeolite framework in an aqueous solvent, the zeolite Is a monosaccharide isomerization method characterized by having pores through which the monosaccharide can pass. Further, the method disclosed herein comprises contacting a monosaccharide with an ordered mesoporous silica material comprising tin or titanium incorporated into the material backbone in an aqueous solvent. It is a conversion method.

  A further method disclosed herein is a method for converting glucose to 5-hydroxymethylfurfural, wherein glucose is contacted with a high silica zeolite containing tin or titanium incorporated in the zeolite framework in an aqueous solvent. Generating fructose, wherein the zeolite has pores through which the glucose can pass, and the step of dehydrating the fructose, Is the method. Further, in the present specification, there is further provided a method for converting starch into 5-hydroxymethylfurfural, wherein the starch is hydrolyzed in an acidic aqueous solvent to produce glucose, and in the aqueous solvent, glucose and zeolite framework Contacting with a high silica zeolite containing tin or titanium incorporated in the sucrose to produce fructose, wherein the zeolite has pores through which the glucose can pass; and And dehydrating fructose.

  The general description herein and the following detailed description are for purposes of illustration and description, and are not intended to limit the scope of the invention as defined in the appended claims. Other aspects of the invention will be apparent to those skilled in the art in view of the detailed description of the invention described herein.

The summary of the invention and the following detailed description of the invention can be better understood with reference to the following drawings. To illustrate the present invention, exemplary embodiments of the present invention are illustrated. However, the present invention is not limited to the specific methods, compositions and devices disclosed herein. Also, the drawings are not always to scale.

FIG. 3 shows the structure and pore size of various different materials synthesized and tested in relation to sugar isomerization activity. The structure and pore size of various different materials synthesized and tested in relation to glycoisomerization activity FIG. The structure and pore size of various different materials synthesized and tested in relation to glycoisomerization activity FIG. It is a figure which shows the structure of the zeolite which contains titanium in frame | skeleton. It is a figure which shows the structure of the zeolite which contains titanium in frame | skeleton. It is a scanning electron microscope image of tin zeolite beta. It is a scanning electron microscope image of tin zeolite beta. It is a scanning electron microscope image of titanium zeolite beta. It is a scanning electron microscope image of titanium zeolite beta. It is a scanning electron microscope image of tin zeolite beta. It is a scanning electron microscope image of tin zeolite beta. It is a figure which shows the ultraviolet / visible diffuse reflection spectrum of Sn-beta and Ti-beta. The It is a figure which shows the powder X-ray-diffraction pattern of Ti-beta and Sn-beta. Significant changes in the structure of Sn-beta after conversion of glucose to HMF in a two-phase system It is a scanning electron microscopic image explaining that the conversion does not occur. FIG. 14 is a Sn-beta image before the reaction. Significant changes in the structure of Sn-beta after conversion of glucose to HMF in a two-phase system It is a scanning electron microscopic image explaining that the conversion does not occur. FIG. 15 is an Sn-beta image after exposing Sn-beta to glucose with a molar ratio of 200, a volume ratio of water: THF of 1: 3, pH in HCl of 1, 100 g of NaCl in 100 g of water. Overview of glucose isomerization pathways catalyzed by biological or chemical catalysts It is a schematic diagram. Schematic of glucose isomerization mechanism via (A) base catalyst or (B) metal catalyst pathway It is. Glucose isomerization via (A) proton rearrangement or (B) intramolecular hydride shift It is the schematic of a mechanism. It is a figure which shows a mail wine-pound ruf-burley (MPV) reaction path | route (R = Alkyl or aryl, R1 and R3 = alkyl or hydrogen, Me = metal). From biomass, downstream products via glucose, HMF, and fructose It is a figure which shows the schematic of the path | route which leads to. Schematic diagram of the pathway from starch to glucose, fructose, and HMF FIG. To produce fructose from glucose and HMF from fructose It is a figure which shows the schematic of the example of use of a two-phase system in reaction for this. Diagram showing screening results of metallic silicate for glucose isomerization reaction It is. The reaction conditions were a 10 wt% aqueous glucose solution, 140 ° C., 90 minutes, and a metal: glucose molar ratio = 1: 50. FIG. 6 shows the results of glucose isomerization reactions catalyzed by various metal-containing solids. (The glucose conversion bar is shaded and the fructose selectivity bar is shown in white). The reaction conditions were a 10 wt% aqueous glucose solution, 413 K, 90 minutes, and a metal: glucose molar ratio = 1: 50. The profile of the glucose isomerization reaction is shown with time on the horizontal axis. The temperature is 3 63K and Sn-beta was used as the catalyst. The reaction conditions were a 10 wt% glucose aqueous solution and a Sn: glucose molar ratio = 1: 50. The error bar is not shown because it is smaller than the data point. The product distribution of the glucose isomerization reaction is shown with time as the horizontal axis (glucose (Hatched from lower left to upper right), fructose (white), and mannose (hatched from upper left to lower right)). The reaction conditions are the same as in FIG. The profile of the glucose isomerization reaction is shown with time on the horizontal axis. The temperature is 3 83K and Sn-beta was used as the catalyst. The reaction conditions were a 10 wt% glucose aqueous solution and a Sn: glucose molar ratio = 1: 50. The error bar is not shown because it is smaller than the data point. The product distribution of the glucose isomerization reaction is shown with time as the horizontal axis (glucose (Hatched from lower left to upper right), fructose (white), and mannose (hatched from upper left to lower right)). The reaction conditions are the same as in FIG. The profile of the glucose isomerization reaction is shown with time on the horizontal axis. The temperature is 4 13K and Sn-beta was used as the catalyst. The reaction conditions were a 10 wt% glucose aqueous solution and a Sn: glucose molar ratio = 1: 50. The error bar is not shown because it is smaller than the data point. The product distribution of the glucose isomerization reaction is shown with time as the horizontal axis (glucose (Hatched from lower left to upper right), fructose (white), and mannose (hatched from upper left to lower right)). The reaction conditions are the same as in FIG. a) unlabeled glucose, b) labeled glucose-D2, c) Sn-beta and glucose Glucose fraction collected after reacting with course-D2, d) glucose fraction collected after reacting labeled glucose-D2 with NaOH, e) unlabeled fructose, f) Sn-beta and glucose-D2 A fructose fraction collected after reacting with, g) a fructose fraction collected after reacting labeled glucose-D2 with NaOH, ¹³ It is a figure which shows a CNMR spectrum. a) unlabeled glucose, b) labeled glucose-D2, c) Sn-beta and glucose Glucose fraction collected after reacting with course-D2, d) glucose fraction collected after reacting labeled glucose-D2 with NaOH, e) unlabeled fructose, f) Sn-beta and glucose-D2 A fructose fraction collected after reacting with, g) a fructose fraction collected after reacting labeled glucose-D2 with NaOH, ¹ It is a figure which shows a HNMR spectrum. (A) Sn-beta or SnO ₂ -React with beta at 383K45 minutes FIG. 2 is a diagram showing glucose isomerization reaction and product distribution (glucose (hatched from the lower left to the upper right), fructose (white), and mannose (hatched from the upper left to the lower right)). The reaction was carried out using a substantial amount of catalyst to maintain a 10 wt% glucose solution, metal: glucose molar ratio = 1: 100. (B) Sn-beta and SnO ₂ -Is a diagram showing the ultraviolet / visible diffuse reflectance spectrum of beta. Conversion rate of glucose isomerization at 383K using Sn-beta as a catalyst It is a figure which shows a profile. The reaction conditions were a 10 wt% glucose aqueous solution (unlabeled and labeled), Sn: glucose molar ratio = 1: 50. A-Pyranose structure glucose content of 35% in unlabeled glucose solution It is a figure which shows the molecular structure (B) of b-pyranose structure glucose contained in a child structure (A) and 65%. It is the same ratio also about a labeled glucose (glucose-D2) solution, 35% is a-pyranose structure (C), and 65% is b-pyranose structure (D). Add to unlabeled glucose, glucose-D2 before heating, and 383K without catalyst Of glucose-D2 after heating ¹³ It is a figure which shows a CNMR spectrum. Add to unlabeled glucose, glucose-D2 before heating, and 383K without catalyst Of glucose-D2 after heating ¹³ It is a figure which shows a CNMR spectrum. It is a figure which shows the reaction experiment result which converts glucose into HMF using a two-phase system. . The reaction conditions were: water: 1-butanol volume ratio = 1: 2, pH = 1 in HCl, 35 g NaCl in 100 g water. It is a figure which shows the reaction experiment result which converts glucose into HMF using a two-phase system. . The reaction conditions were water: organic phase deposition ratio = 1: 3, pH = 1 in HCl, T = 180 ° C., 35 g NaCl in 100 g water. It is a figure which shows the reaction experiment result which converts glucose into HMF using a two-phase system. . The reaction conditions were Sn-beta: glucose molar ratio 200, water: 1-butanol volume ratio = 1: 3, HCl pH = 1, T = 160 ° C., 100 g 35 g salt in water. It is a figure which shows the reaction experiment result which converts glucose into HMF using a two-phase system. . The reaction conditions were Sn-beta: glucose molar ratio 200, water: 1-butanol volume ratio = 1: 3, acid pH = 1, T = 160 ° C., 100 g NaCl 35 g in water. It is a figure which shows the reaction experiment result which converts glucose into HMF using a two-phase system. . The reaction conditions were Sn-beta: glucose molar ratio 200, water: organic phase volume ratio = 1: 3, HCl pH = 1, 100 g NaCl 35 g in water. Results of reaction experiments (reactivity) for converting glucose to HMF using a two-phase system are shown. It is a figure. The reaction conditions were a temperature of 160 ° C., a Sn / beta zeolite: glucose molar ratio of 1: 200, HCl pH = 1, water: 1-butanol volume ratio = 1: 2. Results of reaction experiments (reactivity) for converting glucose to HMF using a two-phase system are shown. It is a figure. The reaction conditions were a temperature of 160 ° C., a Sn / beta zeolite: glucose molar ratio of 1: 200, HCl pH = 1, water: 1-butanol volume ratio = 1: 2. Results of a reaction experiment in which glucose is converted to HMF using a two-phase system (pH = 1 H It is a figure which shows the X-ray-diffraction (XRD) data before and behind exposure to Cl). The reaction conditions were a temperature of 160 ° C., a Sn / beta zeolite: glucose molar ratio of 1: 200, HCl pH = 1, water: 1-butanol volume ratio = 1: 2. It is a figure which shows the thermodynamic data of the difference which isomerizes also fructose from glucose (Based on Tewari, Y., Applied Biochemistry and Biotechnology 1990, 23, 187). Synthesis as described in Andy and Davis, Ind. Eng. Chem. Res. 2004, 43, 2922 It is a figure which shows the X-ray-diffraction pattern of made Zn-CIT-6. It is the scanning electron micrograph of the synthesized Zn-CIT-6, and the crystal size is 0.5. It is a figure which shows that it is -0.6 micron. CIT-6 (SnCH ₃ Cl ₃ ) Glucose carried out at 110 ° C with catalyst This is a product distribution of the isomerization reaction, and shows the case where the prepared catalyst is used (left) and the case where the calcined catalyst is used (right), respectively.

  The present invention may be understood more readily by reference to the following detailed description, taken in conjunction with the accompanying drawings and examples, which form a part of this disclosure. The present invention is not limited to the particular devices, methods, applications, conditions, or parameters described and / or shown herein, and further, the terminology used herein may refer to particular embodiments. It is intended for purposes of illustration and is not intended to limit the invention as claimed. Also, as used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural values unless the content clearly dictates otherwise. . As used herein, the term “plurality” means one or more. When ranges of values are described, other embodiments include ranges up to one particular value and / or another particular value. Similarly, when expressing a value as an approximation with “about”, the particular value forms another embodiment. All ranges can be included and combined.

  For clarity, certain features of the invention that are mentioned in the context of separate embodiments herein can be combined in a single embodiment. Also, for the sake of brevity, the various features of the invention described in a single embodiment of the invention can be used separately or in any sub-combination. Further, references to values within a range include every value within such range.

  As used herein, in characterizing the chemical reactivity of reactant x to form product y, conversion is calculated by dividing the molar amount of reacted x by the initial molar amount of x. Ask for. Selectivity is determined by dividing the molar amount of y produced by the molar amount of x reacted. The yield is determined by dividing the molar amount of y produced by the initial molar amount of x. These values can be described in fractions or percentages. For example, to describe the conversion as a percentage, multiply the reacted x moles by the initial x moles multiplied by 100. Unless otherwise stated, when these values are between 1 and 100, they are percentages, not fractions.

  In some methods disclosed herein, sugars are isomerized using chemical catalysis. Compared to biological catalysis, chemical catalysis, which uses inexpensive inorganic materials to isomerize sugars, can work in a wider temperature range, has a long lasting, fast reaction rate (reactor It is possible to provide attractive effects such as short residual time) and high resistance to impurities.

  For example, glucose isomerizes in the presence of a base catalyst in the temperature range of 298 to 423K, but unfortunately monosaccharides are unstable in alkaline solvents, and at temperatures above 313K, a large number of by-products are immediately produced. It will be disassembled. Thus, the fructose yield of the substrate catalyst will generally be <10% (high fructose selectivity [> 90%] can only be obtained when glucose conversion is low [<10%]). It is difficult to be a candidate for use in large-scale glucose processing.

  Some methods disclosed herein utilize a tin (Sn) or titanium (Ti) metal center that can act as a solid acid in an aqueous solvent when incorporated into the framework of a silica material. For example, large pore zeolites containing this type of acidic center are active in the isomerization of aldoses (eg glucose) and prevent the sugar degradation reactions that normally occur in base catalysis processes.

  By using metal acid centers, strong interactions between these types of metal centers and the hydroxyl / carbonyl moiety present in the aldose can be exploited. Indeed, in a recent report, Sn-Beta zeolite is very active in the Merwine-Pondruf-Burley reduction (MPV) of carbonyl compounds, resulting in a hydride rearrangement from the hydroxyl group of the alcohol to the carbonyl group of the ketone. (Corma A. et al. (2002), “Al-free Sn-Beta zeolite as a selective reduction catalyst for carbonyl compounds (Merwein-Pondruf-Burley reaction). reduction of carbonyl compounds (Meerwein-Ponndorf-Verley reaction)) ", J. Am. Chem. Soc. 124 (13): 3194-95). Similarly, other reports show that Sn-containing materials can be converted from trioses (eg glyceraldehyde and dihydroxyacetone) to alkyl lactate via a Lewis acid mediated isomerization / esterification reaction sequence in the presence of alcohols. It has been shown to have a catalytic action to convert (Hayashi Y. and Sasaki Y. (2005), “Tin-catalyzed conversion of trioses in Alcohol solution by Tin catalysis. to alkyl lactates in alcohol solution), Chem. Commun. 21: 2716-18; Taarning E et al. (2009), “Zeolite-catalyzed isomerization of triose sugars”, ChemSusChem 2 ( 7): 625-27)

  In some methods disclosed herein, the monosaccharide is isomerized, particularly by contacting the monosaccharide with a catalyst in an aqueous solvent. The catalyst may be, for example, an inorganic material containing a metal center.

  In further methods disclosed herein, the inorganic material may be a material comprising silica. The inorganic material may be a porous material, or in particular a molecular sieve, or in particular a microporous structure material (eg zeolite). For example, the inorganic material may be a high silica zeolite.

  Although many zeolites are aluminosilicates, zeolites incorporating other components such as zinc are known in the prior art and their synthesis methods are also known. Some zeolites referred to as high silica have a high ratio of silicon to aluminum in the framework, such as at least about 10: 1, or about 100: 1, or higher. The high silica zeolite may be completely aluminum free. The higher the silicon to aluminum ratio, the more neutral and hydrophobic the skeleton of the zeolite.

  In embodiments where the inorganic material is a porous material, the pores of the material can be designed to be large enough to direct monosaccharides, other reactants, or products into the porous material. For example, when the inorganic material is zeolite, a specific zeolite having a desired pore size can be selected. Pore size is one way to classify zeolites, and zeolites of various pore sizes are known in the prior art. The pore size of the zeolite can be selected to remove unwanted molecules and interfering molecules.

  In embodiments where the inorganic material is a porous material, the material can be designed to exhibit catalytic reactivity within the material. In this case, the reactant enters the material through the pores and reacts to produce a product, and the product exits the material through the pores. In further embodiments, it may have surface reactivity, but such reactivity may be insignificant, negligible, or completely absent. In some embodiments, inorganic materials may be involved in catalytic activity, while in other embodiments, the metal center provides catalytic activity.

  In a further method disclosed herein, the metal center is incorporated into the framework of the inorganic material. For example, the zeolite may contain a metal in the framework of the zeolite. Examples of such zeolites are known in the prior art (eg, Corma A. et al. (2001), “Sn-Zeolite Beta (Sn—) as a chemically selective heterogeneous catalyst for use in Bayer-Billiger oxidation. zeolite beta as a heterogeneous chemoselective catalyst for Baeyer-Villiger oxidations, Nature 412 (6845): 423-25) "). Despite this being known, it is generally necessary to indicate by the characteristics of the zeolite whether or not the metal has been successfully incorporated into the framework of the zeolite.

  In a further method disclosed herein, the metal center acts as a Lewis acid. In such a method, the metal can impart Lewis acid activity to the inorganic material. Generally, in the prior art, many metals that act as Lewis acids (eg, aluminum, boron, chromium, cobalt, iron, titanium, tin, depending on whether they exist as cations, complexes, or covalently bonded compounds. And others) are known. In some methods disclosed herein, for example, the metal center is tin or titanium. Other metals known in the art that are known to have Lewis acid activity are also contemplated for incorporation into the catalyst.

  In a further method disclosed herein, the catalyst may be a zeolite comprising tin or titanium incorporated into the zeolite framework. For example, the catalyst may be a high silica zeolite containing tin or titanium incorporated in the zeolite framework.

  In some methods disclosed herein, the catalyst comprises zeolite beta. Typically, zeolite beta is a zeolite defined by the structure * BEA. Its features are described, for example, in Atlas of Zeolite Framework Types 6th edition (Baerlocher et al., 2007). Consider other zeolites known in the art. Depending on the reaction to be catalyzed, the reactants, and the product, the appropriate framework size, shape, and components are determined and the zeolite is selected accordingly. For example, if the reaction to be catalyzed is isomerization of glucose to fructose, a zeolite having a pore size that allows glucose and fructose to pass through is desirable. Such a zeolite is zeolite beta. Larger reactants and products proportionally require materials with larger pores.

  In other methods disclosed herein, the catalyst comprises a zeolite such as TS-1. TS-1 is a titanosilicate material having an MFI structure. Other various large and extra large zeolites are also considered. They are, for example, CIT-1, ZSM-12, SSZ-33, SSZ-26, CIT-5, or high silica FAU.

  In a further method disclosed herein, the porous material is an ordered mesoporous silica material. For example, monosaccharides are isomerized in aqueous solvents, in particular by contacting monosaccharides with tin or titanium in the skeleton in an ordered mesoporous silica material. The mesoporous silica material may be, for example, MCM-41, SBA-15, TUD-1, HMM-33, or FSM-16.

  In yet another method disclosed herein, the catalyst is contacted with a monosaccharide in an aqueous solution. Here, the aqueous solution means that the solvent is water. For example, the catalyst disclosed herein contacts the monosaccharide in other solvents such as, for example, alcohols. As disclosed elsewhere herein, the choice of solvent significantly affects the results of the chemical reaction.

  In a further method disclosed herein, the catalyst is contacted with a carbohydrate. For example, the catalyst can be contacted with a monosaccharide, disaccharide, trisaccharide, oligosaccharide or polysaccharide. Furthermore, if desired, any combination of carbohydrates can be contacted with the catalyst. In addition, any chiral carbohydrate can be contacted with the catalyst.

  If the carbohydrate is a monosaccharide, the monosaccharide may be, for example, an aldose such as aldtriose, aldetetulose, aldpentose, or aldhexose. In particular, aldoses can include glyceraldehyde, erythrose, threose, ribose, arabinose, xylose, lyxose, allose, altrose, glucose, mannose, gulose, idose, galactose or talose.

  Also, when the carbohydrate is a monosaccharide, the monosaccharide may be, for example, a ketose such as ketotriose, ketotetrose, ketopentose, or ketohexose. In particular, the ketose can include dihydroxyacetone, erythrulose, ribulose, xylulose, psicose, fructose, sorbose, or tagatose.

  Other monosaccharides and their derivatives, including pyranose, furanose, amino sugars, etc. can also be contacted with the catalysts disclosed herein.

  When the carbohydrate is a disaccharide, the disaccharide may be, for example, sucrose, lactulose, lactose, maltose, trehalose, cellobiose, codibiose, nigerose, isomaltose, sophorose, laminaribiose, gentiobiose, tulanose, maltulose, palatinose, gentiobiu It may be any combination of monosaccharides such as gentiobiulose, mannobiose, melibiose, melibulose, rutinose, rutinulose or xylobiose.

  Mixtures of carbohydrates, including mixtures of by-products of the hydrolysis reaction of biomass materials such as starch and cellulose (eg, maltose and cellobiose) can be contacted with the catalysts disclosed herein. Furthermore, as with starch, cellulose and chitin, oligosaccharides and polysaccharides such as, for example, fructooligosaccharides and galactooligosaccharides can be contacted with the catalysts disclosed herein.

  In further methods disclosed herein, the aqueous solvent comprises monosaccharides between about 0.001 weight percent and the maximum amount of solvent dissolved at the selected temperature. For example, the aqueous solvent can comprise between about 0.001 weight percent to about 50 weight percent monosaccharides, or between about 10 weight percent to about 50 weight percent monosaccharides. The aqueous solvent can also include from about 25 weight percent to about 50 weight percent monosaccharides. In particular, it is industrially desirable that the concentration is higher because the convenience of the processing apparatus is improved. The specific monosaccharide concentration is selected depending in part on the solubility of the selected monosaccharide.

In a further method disclosed herein, the isomerization reaction reaches near thermodynamic equilibrium. For example, FIG. 46 shows the equilibrium conversion rate in the conversion from glucose to fructose. In a further method disclosed herein, the isomerization reaction is carried out with a chemical catalyst that provides similar conversion and selectivity as the enzyme systems in the prior art.

  In other methods disclosed herein, the pH of the aqueous solvent is acidic (less than 7.0). For example, as disclosed herein, monosaccharides can be isomerized under non-acidic conditions, but isomerization under acidic conditions is significantly useful. In fact, the ability to isomerize sugars in acidic solutions is important in eliminating some of the major bottlenecks encountered during base catalysis. These bottlenecks include neutralization of the active site by acidic by-products and low sugar stability in an alkaline environment. Furthermore, acting at low pH values can provide an opportunity to combine upstream and downstream acid catalyzed reactions (eg, hydrolysis or dehydration) with glucose isomerization reactions without the need to use additional unit operations. . For example, in the production of high fructose corn syrup (HFCS), the starch hydrolysis step required prior to the isomerization step (generally performed in a separate reactor using an acid catalyst or a combination of enzymes). Could be combined with the glucose isomerization step. Similarly, in the production of HMF, the base catalyzed isomerization step required for the conversion of glucose to fructose, prior to performing the acid-catalyzed dehydration step, can be incorporated into a single reactor to yield product. The rate could be made highly efficient.

  In some methods disclosed herein, the pH of the aqueous solvent is between about 0 and about 4. In further methods disclosed herein, the pH of the aqueous solvent is between about 0 and about 2. A pH value between about 0 and about 2 (including 2) is particularly advantageous for combining isomerization with starch hydrolysis and / or dehydration of fructose to produce HMF.

  In yet other methods disclosed herein, the aqueous solvent comprises a salt. Although salt can exist for many reasons, such as being carried over from previous steps, salt tolerance is advantageous in terms of economy and efficiency. As another example, salt may be intentionally added to facilitate partitioning between multiple liquid phases. In some methods disclosed herein, the salt can include a cation that can be any metal (eg, sodium, potassium, magnesium, calcium, lithium, etc.). Similarly, a salt can be an anion (eg, acetate, alkyl phosphate, alkyl sulfate, carbonate, chromate, citrate, cyanide, formate, glycolate, halide, hexafluorophosphate. Acid salt, nitrate, nitrite, oxide, phosphate, sulfate, tetrafluoroborate, tosylate, triflate or bistrifluorosulfonimide). For example, the salt may be sodium chloride, potassium chloride, magnesium chloride or potassium bromide.

  Furthermore, in another method disclosed in the present specification, isomerization is performed in a temperature range of about 50 ° C. to about 250 ° C. The choice of temperature range affects the reaction rate as well as conversion and selectivity. Depending on the composition of the aqueous solution, the maximum temperature of the reaction depends on the presence or absence of pressurization in the reactor and, if pressurized, the pressure. For example, isomerization can be carried out in the temperature range of about 90 ° C to about 180 ° C. Further, for example, isomerization can be carried out in a temperature range of about 90 ° C to about 140 ° C. If feasible, a relatively low temperature is desirable from the viewpoint of energy saving.

  In further methods disclosed herein, isomerization can be carried out for less than about 90 minutes. In general, the reaction needs to last for a time sufficient to reach the desired conversion. From an industrial point of view, it is desirable that the reaction time is relatively short in terms of efficiency. For example, isomerization can be performed for less than about 60 minutes, or for less than about 30 minutes. The reaction time may be relatively short due to the possibility of accumulation of undesirable degradation products.

  Also, in a further method disclosed herein, the zeolite catalyst can be used in a batch (batch) manner in at least three reaction cycles without significantly degrading performance and without the need for calcination. Select the conditions for the monosaccharide isomerization reaction. Stable catalysts offer several industrially important advantages, including efficiency gains, cost savings, and reliability. In some methods disclosed herein, Sn-beta catalyst is stable and maintains its activity after reuse and after calcination. For example, conversion and selectivity were maintained when a continuous cycle of glucose isomerization was performed without intermediate treatment of the catalyst. In other embodiments disclosed herein, performance can be restored by performing the step of calcining the catalyst in air between cycles even if the performance of the catalyst is degraded. The presence or absence of catalyst performance degradation depends to some extent on the choice of catalyst and reaction conditions. For example, if the reaction time and reaction temperature are maintained at appropriate levels (383 K, 30 minutes), an intermediate step for calcination is not necessary.

  In a further method disclosed herein, the product from monosaccharide isomerization is dehydrated. For example, dehydration produces a furan derivative useful as a chemical intermediate. As a further example, in particular glucose is contacted with a high silica zeolite in which tin or titanium is incorporated in the skeleton in an aqueous solvent to produce fructose and dehydrate the fructose, thereby removing glucose from 5-hydroxymethylfurfural ( HMF). High silica zeolite has pores that allow glucose to pass through.

  In other embodiments of the combination of isomerization and dehydration disclosed herein, the catalyst comprises a zeolite such as beta. Other various large and extra large zeolites are also considered. They are, for example, CIT-1, ZSM-12, SSZ-33, SSZ-26, CIT-5, or high silica FAU. In a further method of combining isomerization and dehydration disclosed herein, the porous material is an ordered mesoporous silica material. For example, monosaccharides are isomerized in aqueous solvents, in particular by contacting the monosaccharides with an ordered mesoporous silica material containing tin or titanium in the backbone. The mesoporous silica material may be, for example, MCM-41, SBA-15, TUD-1, HMM-33, or FSM-16.

  In a further embodiment disclosed herein, the monosaccharide isomerization product dehydration process is carried out in an aqueous solvent. For example, the fructose dehydration treatment is carried out in an aqueous solvent. Such a procedure makes it possible to carry out both the isomerization treatment and the dehydration treatment in the same aqueous solvent without the need for a separation step. The methods disclosed herein are particularly suitable for such procedures because the specific isomerization catalysts disclosed herein are stable under the conditions required for dehydration.

  In general, the dehydration of sugars to produce furan derivatives has been well studied, and in particular, it is known in the prior art to dehydrate fructose to produce HMF. In the specific method disclosed herein, the isomerization reaction product is dehydrated in the presence of an acid catalyst. For example, the catalyst may be an inorganic acid dissolved in an aqueous solvent such as HCl. For example, the catalyst may be a solid acid catalyst such as, for example, a protonated high silica zeolite having a * BEA structure. Other acid sources include cation exchange resins, Lewis acids, silica-alumina materials, titania-alumina materials, mineral acids, heteropoly acids, nitric acid, sulfuric acid, phosphoric acid, boric acid, oxalic acid, levulinic acid, citric acid Niobium oxide, vanadium phosphate or niobium phosphate are also useful.

  The isomerization and dehydration reactions may be performed sequentially or simultaneously, or some combination thereof. For example, both reactions may be performed together by contacting the monosaccharide with an isomerization catalyst and a dehydration catalyst in an aqueous solution. In a particular example, when glucose is contacted with an isomerization catalyst in an aqueous acidic solution, the glucose first produces fructose and then reacts first to produce HMF. The particular reaction conditions may be any of the conditions disclosed in particular in connection with isomerization.

  In some methods of combining isomerization and dehydration disclosed herein, the pH of the aqueous solvent is between about 0 and about 4. In further methods disclosed herein, the pH of the aqueous solvent is between about 0 and about 2. In other methods of combining isomerization and dehydration as disclosed herein, the aqueous solvent includes a salt, and the salt includes a cation that can be any metal (eg, sodium, potassium, magnesium, calcium, lithium, etc.). be able to. Similarly, a salt can be an anion (eg, acetate, alkyl phosphate, alkyl sulfate, carbonate, chromate, citrate, cyanide, formate, glycolate, halide, hexafluorophosphate. Acid salt, nitrate, nitrite, oxide, phosphate, sulfate, tetrafluoroborate, tosylate, triflate or bistrifluorosulfonimide). For example, the salt may be sodium chloride, potassium chloride, magnesium chloride or potassium bromide.

  In other methods disclosed herein, isomerization is performed in a temperature range of about 50 ° C to about 250 ° C. The choice of temperature range affects the reaction rate as well as conversion and selectivity. Depending on the composition of the aqueous solution, the maximum temperature of the reaction depends on the presence or absence of pressurization in the reactor and, if pressurized, the pressure. For example, isomerization can be carried out in the temperature range of about 90 ° C to about 180 ° C. Further, for example, isomerization can be carried out in a temperature range of about 90 ° C to about 140 ° C. If feasible, a relatively low temperature is desirable from the viewpoint of energy saving.

  In further methods disclosed herein, isomerization can be carried out for less than about 90 minutes. In general, the reaction needs to last for a time sufficient to reach the desired conversion. From an industrial point of view, it is desirable that the reaction time is relatively short in terms of efficiency. For example, isomerization can be performed for less than about 60 minutes or less than about 30 minutes. The reaction time may be relatively short due to the possibility of accumulation of undesirable degradation products.

  In yet another method disclosed herein, the combination of isomerization and dehydration reactions can be performed in a two-phase system, as described in US Pat. No. 7,572,925. A two-phase system contains two substantially immiscible liquid phases (one aqueous phase and one organic phase). Two-phase systems are in principle advantageous with regard to conversion, selectivity and production efficiency. In the use of the present invention, saccharides are isomerized in an aqueous phase, and a dehydration reaction of an isomerized product is performed. For example, isomerization of glucose to fructose and dehydration of fructose to HMF are performed in the aqueous phase. In addition, a catalyst for each of these reactions is provided in the aqueous phase. Then, for example, a dehydrated product such as HMF is extracted into the organic phase. Thus, for example, the aqueous solvent can be contacted with an organic medium capable of extracting HMF from the aqueous solvent. In this case, the organic solvent is not substantially mixed with the aqueous solvent. Thereby, the efficiency of the dehydration reaction can be improved without the presence of HMF in the aqueous layer, and the purification can be simplified with the HMF product in the organic layer being in a relatively pure state. Thus, for example, in some methods disclosed herein, HMF is purified in an aqueous solvent and extracted as is from an aqueous solvent to an organic solvent.

  For example, any water immiscible, linear, branched, cyclic alcohol, ether or ketone, or unsubstituted aliphatic or aromatic hydrocarbon, or halo substituted aliphatic or aromatic hydrocarbon, or mixtures thereof Such various solvents can be used as the organic solvent. For example, in some embodiments disclosed herein, the organic solvent comprises 1-butanol or THF. Some components of the organic layer may include compounds that are miscible to some extent with water. Other organic solvent components disclosed in the present specification include, for example, DMSO, DMF, N-methylpyrrolidinone, acetonitrile, acetone, butanone, pentanone, hexanone, heptanone and the like.

  In yet another method disclosed herein, several reactions are combined to convert starch to HMF. As is known in the art, starch can be hydrolyzed with acid to produce glucose. As disclosed herein, isomerization of glucose using the catalysts disclosed herein proceeds well under acidic conditions. Thus, the method disclosed herein specifically includes a high silica zeolite in which starch is hydrolyzed to produce glucose in an acidic aqueous solvent, and in which the glucose is incorporated in the framework with tin or titanium in the framework. The starch is converted to 5-hydroxymethylfurfural by contacting to produce fructose and dehydrate the fructose. High silica zeolite has pores that allow glucose to pass through. In the methods disclosed herein, these three reactions can be combined, for example, holding glucose in an acidic aqueous solvent and contacting with high silica zeolite to produce fructose. Similarly, in the methods disclosed herein, fructose is retained in an acidic aqueous solvent and dehydrated to produce 5-hydroxymethylfurfural. Furthermore, in the methods disclosed herein, for example, all three reactions can be carried out in an aqueous solution in one container. In this case, the first reactant is starch and the final product is HMF.

  In other methods disclosed herein, starch to HMF conversion can be performed, for example, in a two-phase system according to US Pat. No. 7,572,925. The methods disclosed herein and variations thereof applicable to isomerization reactions and combinations of isomerization and dehydration reactions are all applicable to starch to HMF reaction systems, either in aqueous solution or in two-phase systems. can do. Thus, for example, an acidic aqueous solvent is contacted with an organic solvent capable of extracting 5-hydroxymethylfurfural from the acidic aqueous solvent. In this case, the organic solvent is not substantially mixed with the aqueous solvent. And in a further embodiment, 5-hydroxymethylfurfural is produced in an acidic aqueous solvent and extracted as is from an aqueous solvent to an organic solvent.

  Ti-beta zeolite was prepared as follows. 7.503 g of tetraethylammonium hydroxide solution (Sigma Aldrich, 35% by weight, dissolved in water) was diluted with 15 g of water. Then 7.016 g of tetraethyl orthosilicate (Sigma Aldrich, 98 wt%) and 0.201 g of titanium (IV) isopropoxide (Sigma Aldrich, 97 wt%) were added to the solution. The mixture was stirred until tetraethyl orthosilicate and titanium (IV) isopropoxide were completely hydrolyzed, and ethanol, isopropanol and the required amount of water were evaporated to the desired water ratio. Finally, 0.670 g of HF solution (Mallinckrodt, 52% by weight, dissolved in water) was added to form a highly viscous gel.

Gel composition _was SiO ₂ /0.021TiO ₂ /0.54TEAOH/0.53HF/6.6H ₂ O. The gel was transferred to a Teflon-coated stainless steel autoclave and heated at 140 ° C. for 14 days. The solid was collected by filtration, washed thoroughly with water, dried at 100 ° C. overnight. The solid material exhibited a beta zeolite structure (see Ti-beta XRD pattern in FIG. 13 ). The solid was calcined at 580 ° C. for 6 hours to remove organic components in the crystalline material. In the UV-visible diffuse reflectance spectrum of the calcined sample, a characteristic band exists at ˜200-250 nm, which corresponds to the Ti four-coordinate structure in the zeolite framework (Ti— in FIG. 12 ). See Beta).

  Sn-beta zeolite was prepared as follows. 7.57 g of tetraethylammonium hydroxide solution (Sigma Aldrich, 35% by weight, dissolved in water) was diluted with 15 g of water. Tetraethyl orthosilicate (Sigma Aldrich, 98% by weight) 7.011 g and tin (IV) chloride pentahydrate (Sigma Aldrich, 98 parts by weight) were added to the solution. The mixture was stirred until the tetraethyl orthosilicate was completely hydrolyzed and all ethanol and some water were evaporated to the desired water ratio. Finally, 0.690 g of HF solution (Mallinckrodt, 52% by weight, dissolved in water) was added to form a highly viscous gel.

The gel composition was SiO ₂ /0.01SnCl ₄ /0.55 TEAOH / 0.54 HF / 7.52H ₂ O. The gel was transferred to a Teflon-coated stainless steel autoclave and heated at 140 ° C. for 50 days. The solid was collected by filtration, washed thoroughly with water, dried at 100 ° C. overnight. The solid was calcined at 580 ° C. for 6 hours to remove organic components in the crystalline material. X-ray diffraction confirmed that the solid material had a beta zeolite structure (see Sn-beta XRD pattern in FIG. 13 ). In the UV-visible diffuse reflectance spectrum of the calcined sample, a characteristic band exists at ˜200-250 nm, which corresponds to the Sn four-coordinate structure in the zeolite framework (Sn— in FIG. 12). See Beta). By scanning electron microscopy (SEM), the Sn-beta crystal is several microns in size, as shown in FIGS. 6-7 , and the energy dispersive X-ray spectrum (EDS) measurement results for the Sn-beta sample show that Si: Sn It became clear that the atomic ratio was 96: 1.

TS-1 was synthesized according to the method described in the patent literature (US Pat. No. 4,410,501). TS-1 is prepared by mixing titanium butoxide (TNBT, Sigma-Aldrich), tetraethyl orthosilicate (TEOS, Sigma-Aldrich), tetrapropylammonium hydroxide (TPAOH, 1M, Sigma-Aldrich), and distilled water. Crystallized from the clear solution. The mixture was stirred to completely hydrolyze tetraethyl orthosilicate and titanium butoxide. Then, total ethanol and butanol and some water were evaporated to a desired water ratio. The gel composition was SiO ₂ /0.03 TiO ₂ /0.44 TPAOH / 30H ₂ O. The TS-1 reaction mixture was transferred to a Teflon-coated autoclave and crystallized at 175 ° C. for 5 days. The autoclave was rotated at 50 rpm. After cooling, the filtered solid was collected, washed thoroughly with water, dried at 100 ° C. overnight. The material was baked at 580 ° C. for 6 hours to remove organic components in the crystalline material.

A Ti-MCM-41 sample was synthesized as follows. A solution of hexadecyltrimethylammonium bromide (C16TABr) was prepared (1.93 g of C16TABr against 15.1 g of water). Then, 6.42 g of tetramethylammonium hydroxide solution (25%, Aldrich) was added. After homogenization, 7.015 g of tetraethyl orthosilicate (Sigma Aldrich, 98 wt%) and 0.19 g of titanium (IV) isopropoxide (Sigma Aldrich, 97 wt%) were added to the solution. The mixture was stirred to completely hydrolyze tetraethyl orthosilicate and titanium (IV) isopropoxide. The total ethanol and total isopropanol and some water were then evaporated to the desired water ratio. The final compound was as follows: 1.0 SiO ₂ /0.02 TiO ₂ /0.16 C16 TABr / 0.26 TMAOH / 24.8H ₂ O. The uniform gel was encapsulated in a Teflon coated stainless steel autoclave and heated at 135 ° C. for 48 hours under static conditions. The solid was collected by filtration, washed thoroughly with water, dried at 100 ° C. overnight. The solid was calcined at 580 ° C. for 6 hours to remove organic components in the crystalline material.

A Sn-MCM-41 sample was synthesized as follows. A solution of hexadecyltrimethylammonium bromide (C16TABr) was prepared (1.46 g of C16TABr against 4.3 g of water). Then, 6.34 g of tetramethylammonium hydroxide solution (25%, Aldrich) was added. After _{homogenization, SnCl 4 · 5H 2 O (} 98%, Aldrich) 0.088 g and colloidal silica solution (Ludox AS-40, Sigma-Aldrich) and 3.76 g, was added continuously with stirring. The final compound was as follows: 1.0SiO ₂ /0.01SnCl ₄ /0.16 C16TABr / 0.35 TMAOH / 25H ₂ O. The uniform gel was encapsulated in a Teflon coated stainless steel autoclave and heated at 135 ° C. for 48 hours under static conditions. The solid was collected by filtration, washed thoroughly with water, dried at 100 ° C. overnight. The solid was calcined at 580 ° C. for 6 hours to remove organic components in the ordered array material.

  Various materials were synthesized by known methods. The following table shows the synthesized materials and their Si / metal ratio. The Si / metal ratio was measured by energy dispersive X-ray spectrum (EDS).

  The synthesis of these materials was according to the following literature as described in Examples 1-5. ([1] Corma, A. et al., J. Phys. Chem. C, 2009, 113 (26), pp. 11306.11315; [2] CB Khouw, HX Li and ME Davis, Micropor. Mater. 2. (1994) , p. 425; [3] Blasco et al., J. Catal., 1995, 156, p. 65; [4] Ti-MCM-41 samples were treated with hexamethyldisilazane to capped silanols on the surface; [5] Corma, A. et al., ARKIVOC, 2005, ix, p. 124)

  Powder X-ray diffraction (XRF) patterns were measured with a Scintag XDS 2000 diffractometer using Cu, Ka radiation. The measured value at EHT (electron high tension) = 10 kV was recorded on a LEO 1550VP FE SEM by scanning electron microscopy (SEM) with energy dispersive X-ray spectrum (EDS). UV-visible measurements were recorded using a Cary 3G spectrophotometer equipped with a diffuse reflectance cell.

  Glucose isomerization experiments were performed in a 10 mL thick wall glass reactor (VWR) heated in a temperature controlled oil bath placed on a digital stirred hot plate (Fisher Scientific). In a typical experiment, 1.5 g of an aqueous solution containing a substantial amount of catalyst (usually ˜70 mg) with a 10 wt% glucose and metal: glucose molar ratio of 1:50 was added to the reactor and sealed. The reactor was placed in an oil bath and removed at specific times. The reactor was cooled in an ice bath to stop the reaction and a small aliquot was taken and analyzed. Sample analysis was performed using high performance liquid chromatography (HPLC) using an Agilent 1200 system (Agilent Technologies) equipped with PDA UV (320 nm) and evaporative light scattering detection (ELS) detectors. Glucose and fructose concentrations were monitored by a Phenomenex RHM column (Phenomenex) using ultra high purity water (pH = 7) with a flow rate of 0.55 mL / min and a column temperature of 353 K as the mobile phase.

  The following table summarizes the results of glucose isomerization experiments.

A series of materials containing Lewis acidic centers with different activities in the glucose isomerization reaction were tested. The test was incorporated into a framework of tantalum (Ta), tin (Sn) and titanium (Ti) metal centers, zeolite with moderate pores (TS-1) incorporated into a beta zeolite framework with large pores. Ti, as well as Sn and Ti incorporated into an ordered mesoporous silica support (SBA-15). As shown in FIG. 23 , under these conditions, Sn-beta and Ti-beta exhibited the highest isomerization activity and exhibited a glucose conversion of greater than 50% at 140 ° C. for 90 minutes. In contrast, under the same reaction conditions, Sn-SBA and Ti-SBA exhibited moderate isomerization activity, and TS-1 and Ta-beta materials revealed little isomerization activity. It was. The difference in reactivity between TS-1 and Ti-beta suggests that the TS-1 pore diameter is too small to pass glucose molecules into the zeolite.

  A closer examination of the kinetics of the two most active materials revealed that Sn-beta catalyst isomerizes glucose with better performance than Ti-beta. Specifically, the fructose selectivity exceeded 90% at 110 ° C. for 45 minutes and 140 ° C. for 15 minutes at the reaction equilibrium (ie, glucose conversion 50%). The value of fructose selectivity decreased when the reaction was allowed to proceed for a relatively long time due to the initiation of the fructose degradation reaction (see entries 5d and 10e). Although the Ti-beta catalyst was active, it was not as effective as the Sn-beta catalyst under the conditions described above, with a glucose conversion of 18% and fructose selectivity of 80% after reaction at 110 ° C. for 45 minutes. After the reaction at 140 ° C. for 45 minutes, the glucose conversion was 44% and the fructose selectivity was 68%.

  The inventors observed an interesting solvent effect related to the activity of Sn-beta in the isomerization reaction. Unlike basic catalysts, Sn-beta catalysts were able to carry out isomerization reactions in an acidic environment. Here, the main drawback of the basic catalyst used in the reactions described herein is that the active site is neutralized by the carboxylic acid formed during the saccharide decomposition reaction. It will be deactivated. However, when Sn-beta was used in an acidic glucose solution (pH = 2, HCl), there was no difference in activity or fructose selectivity compared to when performed in a non-acidic solution (entry 5c). And 6c). In contrast, Sn-beta had no activity for the isomerization reaction when an aprotic solvent (dimethyl sulfoxide [DMSO]) was used instead of water (see entries 11c and 12c).

  The table below summarizes glucose isomerization experiments performed using various catalysts in water. The reaction was carried out using 10% by weight glucose and a substantial amount of catalyst with a metal: glucose molar ratio of 1:50. For entry 10 (shown with *), the reaction was carried out such that the molar ratio of glucose: Sn was 225: 1 with respect to the 45 wt% glucose solution. ** indicates that unidentified sugars other than mannose were obtained by Ti-beta. The stated yield of 5% by weight was calculated using response counts for hexose.

A series of silica materials containing Sn or Ti metal centers were screened based on their activity in the glucose isomerization reaction. Specifically, Sn and Ti metal centers are incorporated into the framework of large pore zeolite (beta), Ti is incorporated into zeolite (TS-1) with medium pores, and Sn and Ti are ordered Incorporated into aligned mesoporous silica (MCM-41). Under these conditions, Sn-beta and Ti-beta showed the highest glucose isomerization activity, and the glucose conversion after the reaction of 413K 90 minutes was more than 50% (see FIG. 24 ). In contrast, under the same reaction conditions, Sn-MCM41 and Ti-MCM41 showed moderate activity and TS-1 was substantially inactive (see FIG. 24 ). The difference in reactivity between TS-1 and Ti-beta is that glucose molecules can diffuse in beta zeolite pores (pore diameter: approximately 0.8 nm), while TS-1 pores (pore diameter: 0). 0.5-0.6 nm) suggests that it cannot diffuse.

In further reaction experiments using the two most active materials, it was found that the Sn-beta catalyst isomerizes glucose with superior performance compared to Ti-beta. Specifically, the yield after reacting 30 wt% and 12 min at 383K and 413K for a 10 wt% glucose solution containing a catalytic amount of Sn-beta (Sn: glucose molar ratio = 1: 50), respectively. Was about 46% (w / w) glucose, about 31% (w / w) fructose, and about 9% (w / w) mannose. Even when the reaction was allowed to proceed for a longer time at 383 K, the Ti-beta catalyst had very low glucose conversion (see entries 4 and 7). When reaction time became long, the yield of all the saccharides fell by autocatalytic decomposition reaction (refer FIGS. 25-30 ). Changing the reaction temperature had no effect on the total amount of sugar lost at a given glucose conversion value, so the pathway of the degradation reaction has a clear activation barrier, similar to the pathway of the isomerization reaction. Was suggested. In particular, Sn-beta catalysts can be used for higher concentration glucose solutions, similar to those used in large scale conversions. For example, a product consisting of glucose 46% (w / w), fructose 29% (w / w), and mannose 8% (w / w) would be able to catalyze Sn-beta at 383 K for 60 minutes ( (Sn: glucose molar ratio = 1: 225) obtained by reacting a 45 wt% glucose solution (see entries 4 and 10). Such a result is close to that obtained by an industrial enzyme treatment method, and is a high fructose yield obtained from a highly concentrated glucose solution using an inorganic catalyst.

This data suggests that the active site of the Sn-beta isomerization reaction is the Sn atom incorporated into the zeolite framework. Neither SnCl ₄ · 5H ₂ O nor SnO ₂ showed isomerization activity (see entries 8 and 9), and the UV data for Sn-beta did not exhibit an absorption band corresponding to the further framework Sn (FIG. 12 ). reference).

  The table below summarizes the experimental results of catalyst stability. The reaction was carried out at 383 K using a 10 wt% glucose solution with a Sn: glucose molar ratio of 1:50 (except entry 5b). For experiment 1 (entries 1 to 4), after each cycle, the catalyst was washed with water and a new glucose solution was added to start a new cycle. In cycle 4, the catalyst recovered from cycle 3 was calcined in air at 813 K for 3 hours at a temperature ramp rate of 2 K / min. For experiment 2 (entries 5a-5b), the reaction with Sn-beta was continued for 12 minutes (entry 5a). Thereafter, the solution was filtered while hot to recover the catalyst, and the filtered solution was further reacted for 30 minutes (entry 5b).

  To test the stability of the Sn-beta catalyst, two experiments were performed. In the first experiment, catalyst reusability was evaluated by performing four consecutive isomerization cycles, each for 30 minutes at 383 K. After each cycle, the catalyst was recovered by filtration and washed with water before adding fresh glucose solution. As is apparent from the data, after three reaction cycles, the catalyst maintained its initial activity and product distribution. After the third cycle, the catalyst was calcined in air at 813 K before performing the last cycle. The results of cycle 4 revealed that the catalyst again maintained its initial activity and product distribution. Therefore, it was confirmed that the catalyst according to the present invention can withstand the Tein-type zeolite regeneration process. The second test was designed to confirm the presence of homogeneous catalysis due to metal species leaching into the solution. Specifically, the isomerization cycle was initialized with Sn-beta catalyst at 383 K for 15 minutes. And while the solution was still hot, the catalyst was removed by filtration.

  The filtered solution was reacted at 383 K for 30 minutes to avoid the possibility that the metal species leached during cooling would be adsorbed again. The reaction results showed that glucose isomerization proceeded as expected in the presence of catalyst (product yields were 57% glucose (w / w), 27% fructose (w / w), and Mannose was 6% (w / w)). However, once the catalyst is removed, the reaction does not persist, suggesting that homogeneous catalysis is not caused by the leached metal ions (entries 5a and 5b). These two test results suggest that Sn-beta has heterogeneous catalysis for the isomerization reaction and can be used for multiple reaction cycles.

  The table below summarizes the results of the Sn-catalyzed glucose reaction in water under 413K acidic conditions.

  Surprisingly, Sn-beta can perform isomerization reactions in highly acidic environments. When reacted with Sn-beta in an acidic 10 wt% glucose solution (pH = 2, HCl) compared to reacting without HCl (see Example 9, entries 4 and 6) There was no difference in activity and product distribution. In experiments using Sn-beta in an acidic environment, the results of hydrolysis / isomerization and isomerization / dehydration reaction sequences were good. Specifically, when a 10% by weight starch solution is hydrolyzed with HCl (pH = 1) at 413 K for 90 minutes, a solution of glucose 87% (w / w) and starch 13% (w / w) is obtained. The product distribution is obtained by adding a catalytic amount of Sn-beta (Sn: glucose molar ratio = 1: 50) to the resulting acidic solution and isomerization by heating at 413 K for an additional 12 minutes. Starch 13% (w / w), glucose 39% (w / w), fructose 23% (w / w), and mannose 7% (w / w) (Table 3, entries 1a and 1b). Further, when a 10 wt% glucose solution was reacted at 413 K for 120 minutes under the condition where both HCl (pH = 1) and Sn-beta were present, the yield of HMF was 11% (w / w), In addition, fructose was 18% (w / w) and mannose was 2% (w / w) (entry 4). These data show that dehydration results when reacting fructose in aqueous HCl (HMF yield 24% (w / w), conversion 85%; entry 3) and glucose under similar aqueous HCl reaction conditions. It can be compared with the result of dehydration (HMF yield less than 1% (w / w), conversion rate 9%; entry 2). Thus, Sn-beta is attractive as a candidate for a one-pot reaction sequence that requires a combination of isomerization and other acidic catalytic reactions.

The isomerization reaction was analyzed by NMR using C-2 position deuterated glucose (glucose D2, FIG. 35 ). As shown in FIG. 18 , the proton at the C-2 position plays a fundamental role regardless of which route the reaction mechanism follows. In fact, isotopic substitution at the C-2 position resulted in a reduction in the initial reaction rate by half (k _H / k _D = 1.98, FIG. 34 ). From this, it is clear that the isotope significantly affected the reaction rate. Significantly, the ¹³ C NMR spectrum of glucose D2 in water at the reaction temperature (383 K) in the absence of catalyst revealed that no isotope scrambling occurred (Figures 36-37 ). Such a result suggests that the CD bond is inactivated in water under the reaction conditions, and that no isotopic rearrangement occurs in the molecule during the reaction due to the catalytic action alone. It is important to suggest.

The isomerization of glucose D2 using Sn-beta as a catalyst was analyzed by ¹³ C NMR and ¹ HNMR spectroscopy. Comparing the ¹³ C NMR spectra of unlabeled glucose and glucose D2 raw material solution, the resonance observed at δ = 74.1, 71.3 ppm in the unlabeled glucose solution is a low intensity 1: 1: 1 in the glucose D2 solution. may appear as a triplet revealed (Figure 31 a, b). This effect is related to the decay of nuclear overhauser enhancement (NOE) by deuterated atoms at the C-2 position in the two structures of glucose D2 in solution (b-pyranose and a-pyranose, abundance 64:36). To do. During NOE, when C and H couplings are suppressed using ¹ H broadband coupling, the ¹³ C resonance intensity is emphasized up to 200% due to the direct binding of ¹³ C ¹ H pairs. Is not seen for the ¹³ C- ¹ H pair, and thus the resonance associated with C-2 of glucose D2 is substantially attenuated. After reacting a 10 wt% glucose D2 solution in water in the presence of Sn-beta at 383K for 15 minutes, the glucose and fructose fractions were separated by high performance liquid chromatography (HPLC). Analysis of the ¹³ C NMR spectrum for each fraction revealed that glucose D2 was unchanged after the reaction (FIG. 31 b, c), while the fructose product was compared to the unlabeled fructose standard (FIG. 31 e, f). It was revealed that there was a significant difference. In particular, the resonance at δ = 63.8, 62.6 ppm corresponding to the C-1 position of the b-pyranose and b-furanose structures in the unlabeled fructose standard appears as a low intensity triplet of the fructose product recovered after the reaction. It was. These results were confirmed by ¹ H NMR spectra for both sugars. The ¹ H NMR spectrum of glucose D2 before and after the reaction remained constant (FIGS. 32 b and c), but the fructose spectrum was δ = 3.45 ppm resonance due to the disappearance of the deuterium atom at the C-1 position. There showed that disappeared (Fig. 32 f). By integrating the regions of these spectra, it can be confirmed that there are 6 CH pairs for the glucose and fructose fractions described above and 7 CH pairs for unlabeled glucose or fructose. It was. Such results demonstrate that the deuterium atom at the C-2 position of glucose D2 has moved to the C-1 position of fructose, and therefore the glucose isomerization reaction with the solid Lewis acid catalyst in pure water is It has been reliably proved to proceed by intramolecular hydride shift.

Similar spectroscopic analysis was performed using sodium hydroxide (NaOH) as the basic catalyst. A 10 wt% aqueous solution of glucose D2 was reacted at 383 K for 2 minutes in the presence of NaOH (0.1 M). And when the ¹³ CNMR and ¹ H NMR spectra of the glucose and fructose fractions were obtained, a significant difference was shown in comparison with the results when Sn-beta was used. First, there was no difference in the ¹³ C NMR and ¹ H NMR spectra for unlabeled fructose and the fructose fraction separated after the reaction. This indicates that no contains deuterium atoms into fructose fraction (FIG. 31 e, g and Figure 32 e, g). Second, in ¹³ CNMR spectrum of glucose fragments, [delta] = the presence of a small resonance at 74.1Ppm, it was mixed a small amount of standard glucose to glucose D2 was suggested (see enlarged view in FIG. 31 d ). The presence of unlabeled ^glucose, 1 in HNMR spectrum, also supported by the appearance of resonances at [delta] = 3.1 ppm corresponding to the proton of the C-2 position (FIG. 32 d). These results show that the basic catalyst removes deuterium from the a-carbonyl carbon of glucose D2 to produce the corresponding enolate, re-incorporates protons from solution into the glucose molecule, and accompanies unlabeled fructose. It was shown to activate a proton transfer mechanism that produces some unlabeled glucose (FIG. 18A ).

This experiment showed that Sn-beta can act as a Lewis acid that can catalyze the isomerization of glucose in pure aqueous solvents. During the isomerization reaction, further experiments were conducted to understand the nature of the interaction between the active site of Sn-beta and sugars and solvents. In a report by Corma et al. (Using ¹¹⁹ Sn-NMR), the framework tin center in the separated zeolite was shown to play a role in accelerating the kinetics of certain reactions (A. Corma, Nature 2001, 412). , 423). For glucose isomerization in water, the inventors have found that a skeletal tin center is essential for Sn-beta to catalyze the reaction. Sn-beta synthesized by a procedure that is supposed to completely incorporate tin into the skeleton (using SnCl as the tin source) was highly active for the isomerization reaction, but was synthesized using SnO as the tin source Sn-beta was completely inactive (FIG. 33A ). In the UV-visible diffuse reflectance spectrum of the active substance, a single band centered at 220 nm (corresponding to a metal four-coordinate structure) was observed, but the spectrum of the non-active material was a band centered at 300 nm (skeleton It corresponds to Hachihai position structure of the metal outer position) exhibited (Figure 33 B).

  The results of further glucose isomerization experiments are summarized in the table below.

  The results of the glucose to HMF conversion experiment are summarized in the table below.

Zeolite Sn-CIT-6 was synthesized and subjected to glucose isomerization reaction. Zinc silicate CIT-6 was synthesized according to the procedure described in the literature (Andy and Davis, Ind. Eng. Chem. Res. 2004, 43, 2922). The X-ray diffraction pattern of the synthesized material is shown in Figure 47. An electron micrograph of the synthesized material is shown in Figure 48. In order to remove Zn from the framework, 1.0 g of zeolite was added to 60 mL of glacial acetic acid and 100 mL of water, and the mixture was maintained at 80 degrees for 3 days. CIT-6 was recovered by filtration, washed with water, dried at 100 ° C. overnight. The sample was heated to 130 ° C. and heated in vacuum for 2 hours to remove the adsorbed water. At room temperature, in anhydrous chloroform, considerable amount of grafting agent (Si / Sn: 100~125) in the solution was grafted CIT-6 of Sn (SnCl ₃ CH _3). After 1 hour, triethylamine was added to the mixture to trap the hydrochloric acid produced in the grafting process. The suspension was stirred and maintained for 2 days. The sample was washed with chloroform and dried at 100 ° C. overnight. The final Si / Sn ratio of CIT-6 (SnCl ₃ CH ₃ ) was 110 (calculated by EDS). A part of the sample was baked at 580 ° C. for 6 hours.

The reaction conditions for the glucose isomerization were as follows: the temperature was 110 ° C. and the reaction time was 90 minutes for a 10 wt% glucose aqueous solution having a sugar: Sn ratio of 100. As shown in FIG. 49 , CIT-6 (SnCH ₃ Cl ₃ ) becomes active for the glucose isomerization reaction when calcined. This suggests that for efficient grafting, the alkyl group must be removed by oxidation by calcination. This trend is also described in Corma et al., J. Catal, 2003, 219, 242. FIG. 49 shows glucose isomerization at 110 ° C. using as-prepared CIT-6 (SnCH ₃ Cl ₃ ) catalyst (left) and calcined CIT-6 (SnCH ₃ Cl ₃ ) catalyst (right). The product distribution from the reaction is shown.

Claims (28)

In an aqueous solvent, characterized in including that contacting a beta zeolite containing tin incorporated into monosaccharides glucose and beta zeolite framework (Sn) or titanium (Ti), to the monosaccharide glucose fructose Isomerization method. The method according to claim 1, wherein the beta zeolite is Sn-beta zeolite . The method according to claim 1, wherein the beta zeolite is Ti-beta zeolite . The aqueous solvent is characterized in that it comprises 1 0 wt% to 5 0% by weight of monosaccharides, method according to any one of claims 1-3. The process according to any one of claims 1 to 3 , characterized in that the isomerization reaches a substantially thermodynamic equilibrium. The method according to claim 1, wherein the pH of the aqueous solvent is acidic. The method according to any one of claims 1 to 3, wherein the pH of the aqueous solvent is 0-2 . The method according to any one of claims 1 to 3, wherein the aqueous solvent contains a salt. The salts include acetate, alkyl phosphate, alkyl sulfate, carbonate, chromate, citrate, cyanide, formate, glycolate, halide salt, hexafluorophosphate, nitrate, 9. A process according to claim 8 , characterized in that it comprises nitrates, oxides, phosphates, sulfates, tetrafluoroborate, tosylate, triflate or bistrifluorosulfonimide. 9. The method according to claim 8 , wherein the salt is sodium chloride, potassium chloride, magnesium chloride or potassium bromide. The method according to any one of claims 1 to 3, wherein the isomerization is performed at a temperature of 90 ° C to 180 ° C. The process according to any one of claims 1 to 3 , characterized in that the isomerization is carried out for less than 90 minutes. Without significantly reducing the performance, without the need for baking, as may be used batchwise in at least three reaction cycles zeolite catalysts, the reaction conditions are selected, characterized in that in claim 2 The method described. The method according to any one of claims 1 to 3 , further comprising converting the monosaccharide glucose to fructose and dehydrating the fructose to 5-hydroxymethylfurfural . 15. The method of claim 14 , further comprising maintaining the fructose in the aqueous solvent during the fructose dehydration. The method according to claim 14 , wherein the dehydration step is performed in the presence of an acid catalyst. The method according to claim 16 , wherein the catalyst is an inorganic acid dissolved in the aqueous catalyst. The method according to claim 16 , wherein the catalyst is a solid acid catalyst. The method according to claim 14 , wherein the pH of the aqueous solvent is 0-2 . The method of claim 14 , wherein the aqueous solvent comprises a salt. The salts include acetate, alkyl phosphate, alkyl sulfate, carbonate, chromate, citrate, cyanide, formate, glycolate, halide salt, hexafluorophosphate, nitrate, 21. Process according to claim 20 , characterized in that it comprises nitrates, oxides, phosphates, sulfates, tetrafluoroborate, tosylate, triflate or bistrifluorosulfonimide. 21. The method of claim 20 , wherein the salt is sodium chloride, potassium chloride, magnesium chloride or potassium bromide. 15. The method of claim 14 , wherein the aqueous solvent comprises 10 weight percent to 50 weight percent glucose. Contacting said aqueous solvent with an organic solvent capable of extracting 5-hydroxymethylfurfural from said aqueous solvent, and wherein said organic solvent is substantially immiscible with said aqueous solvent, Item 16. The method according to Item 15 . 25. The method of claim 24 , wherein the 5-hydroxymethylfurfural is produced in the aqueous solvent and is extracted as is from the aqueous solvent into the organic solvent. 25. The method of claim 24 , wherein the organic solvent comprises a solvent that is water immiscible, linear, branched, cyclic alcohol, ether or ketone. 25. The method of claim 24 , wherein the organic solvent comprises a solvent that is an unsubstituted aliphatic or aromatic hydrocarbon, or a halo-substituted aliphatic or aromatic hydrocarbon. The method of claim 24 , wherein the organic solvent comprises 1-butanol or THF.