Method for directly preparing 2, 5-furandicarboxylate from carbohydrate

Abstract

The invention discloses a preparation method for directly preparing 2, 5-furandicarboxylate from a carbohydrate compound, and the preparation method comprises the following steps: reacting a mixture I containing the carbohydrate compound, a catalyst, an alcohol compound, an organic solvent and a water phase in an oxygen-containing atmosphere to obtain 2, 5-furandicarboxylate, the catalyst comprises a component I and a component II; the component I is selected from at least one of aluminum chloride, indium chloride and chromium chloride; and the component II is an organic hydrophobic modified cobalt-manganese composite catalyst. According to the method, a 5-hydroxymethylfurfural intermediate product generated by reaction is directly oxidized and esterified without separation to prepare 2, 5-furandicarboxylate, so that side reactions such as polymerization and the like are reduced; the carbohydrates are dissolved in the water phase and cannot be catalyzed and oxidized by the hydrophobic oxidation catalyst dispersed in the organic phase to generate byproducts, and the method has the advantages of low cost, mild reaction conditions, high product yield and the like.

Description

Technical Field

[0001] The present application relates to a method for directly preparing 2,5-furandicarboxylic acid ester from a carbohydrate compound, and belongs to the technical field of organic chemical industry. Background Art

[0002] 2,5-Furandicarboxylic acid and its esters are important furan platform compounds, one of the new energy chemicals that have attracted much attention, and are important monomers for the preparation of bio-based polyesters, unsaturated resins, etc. 2,5-Furandicarboxylic acid esters are mainly produced by selective oxidative esterification of 5-hydroxymethylfurfural. However, 5-hydroxymethylfurfural is very expensive, which seriously hinders the application of 2,5-furandicarboxylic acid esters. 5-Hydroxymethylfurfural can be produced by catalytic dehydration conversion of glucose, fructose, etc., but 5-Hydroxymethylfurfural is unstable and side reactions such as polymerization are prone to occur during the separation process, resulting in a very high production cost of 5-Hydroxymethylfurfural.

[0003] CN107739354A reported a method for preparing 2,5-furandicarboxylic acid from a carbohydrate compound. The method uses fructose as a raw material, and the yield of 2,5-furandicarboxylic acid is less than 50%. CN110256381A reported a method for preparing 2,5-furandicarboxylic acid from fructose, sucrose, glucose, etc., using fructose as a raw material, and the yield of 2,5-furandicarboxylic acid is about 50%; using sucrose, glucose, etc. as raw materials, the yield of 2,5-furandicarboxylic acid is less than 40%, the reaction pressure is 6-8MPa, and the reaction temperature is 185-195°C. Summary of the invention

[0004] In order to solve the current problems of high cost of preparing 5-hydroxymethylfurfural, harsh reaction conditions for preparing 2,5-furandicarboxylic acid and its esters from sugar compounds such as glucose and sucrose, and low product yield, the present application provides a method for directly preparing 2,5-furandicarboxylic acid esters from sugar compounds, and the 5-hydroxymethylfurfural intermediate product generated by the reaction is directly oxidized and esterified to prepare 2,5-furandicarboxylic acid esters without separation, thereby reducing side reactions such as polymerization, and has the advantages of low cost, mild reaction conditions, and high product yield.

[0005] According to one aspect of the present application, a method for directly preparing 2,5-furandicarboxylic acid ester from a carbohydrate compound is provided, the preparation method comprising:

[0006] Under an oxygen-containing atmosphere, a mixture I containing a sugar compound, a catalyst, an alcohol compound, an organic solvent, and an aqueous phase is reacted to obtain 2,5-furandicarboxylic acid ester;

[0007] The catalyst comprises component I and component II;

[0008] The component I is selected from at least one of aluminum chloride, indium chloride and chromium chloride;

[0009] The component II is an organic hydrophobically modified cobalt-manganese composite catalyst.

[0010] Optionally, the organic hydrophobically modified cobalt-manganese composite catalyst is a cobalt-manganese composite catalyst complexed with a long-chain fatty diamine.

[0011] Optionally, the long-chain fatty diamine in the long-chain fatty diamine-complexed cobalt-manganese composite catalyst is selected from at least one of C6 to C12 fatty diamines.

[0012] Optionally, the preparation method of the long-chain fatty diamine complexed cobalt-manganese composite catalyst comprises:

[0013] A mixture II containing an ethanol-water solution of Co(OAc)2, an ethanol-water solution of Mn(OAc)2, and an ethanol solution of a long-chain fatty diamine is reacted to obtain a cobalt-manganese composite catalyst complexed with a long-chain fatty diamine;

[0014] The long-chain fatty diamine in the ethanol solution of the long-chain fatty diamine is selected from at least one of C6 to C12 fatty diamines.

[0015] Optionally, the preparation method of the long-chain fatty diamine complexed cobalt-manganese composite catalyst is: adding a mixed ethanol-water solution of Co(OAc)2 and Mn(OAc)2 dropwise to an ethanol solution of a long-chain fatty diamine, and performing reaction II to obtain a long-chain fatty diamine complexed cobalt-manganese composite catalyst.

[0016] Optionally, the C6-C12 fatty diamine is independently selected from at least one of hexamethylenediamine, heptamethylenediamine, octanediamine, nonamethylenediamine, decanediamine, undecanediamine and dodecanediamine.

[0017] Optionally, the concentration of the Co(OAc)2 ethanol-water solution is 0.1-0.3 mol / L.

[0018] Optionally, the concentration of the Co(OAc)2 ethanol-water solution is independently selected from any value among 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L or a range between any two of the above.

[0019] Optionally, the concentration of the Mn(OAc)2 ethanol-water solution is 0.1-0.3 mol / L.

[0020] Optionally, the concentration of the Mn(OAc)2 ethanol-water solution is independently selected from any value among 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L or a range between any two of the above.

[0021] Optionally, the molar ratio of Co(OAc)2 in the ethanol-water solution of Co(OAc)2 to Mn(OAc)2 in the ethanol-water solution of Mn(OAc)2 is 1:1 to 2:1.

[0022] Optionally, the molar ratio of Co(OAc)2 in the ethanol-water solution of Co(OAc)2 to Mn(OAc)2 in the ethanol-water solution of Mn(OAc)2 is independently selected from any value of 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1 or a range between any two of the above.

[0023] Optionally, the molar ratio of the total amount of Co(OAc)2 and Mn(OAc)2 to the long-chain fatty diamine is 1:1 to 1:2.

[0024] Optionally, the molar ratio of the sum of the moles of Co(OAc)2 and Mn(OAc)2 to the molar ratio of the long-chain fatty diamine is independently selected from any value of 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2 or any range between two values.

[0025] Optionally, in the ethanol-water solution, the volume ratio of ethanol to water is 3:1 to 7:1.

[0026] Optionally, in the ethanol-water solution, the volume ratio of ethanol to water is independently selected from any value of 3:1, 4:1, 5:1, 6:1, 7:1 or a range between any two of the above values.

[0027] Optionally, the temperature of reaction II is 25-50° C., and the time of reaction II is 6-24 h.

[0028] Optionally, the temperature of the reaction II is independently selected from any value of 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, or a range between any two of the above values;

[0029] Optionally, the time of the reaction II is independently selected from any value of 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or a range between any two of the above.

[0030] Optionally, the carbohydrate compound is selected from at least one of fructose, glucose and sucrose.

[0031] Optionally, the alcohol compound is selected from at least one of methanol, ethanol, propanol and butanol.

[0032] Optionally, the 2,5-furandicarboxylic acid ester is selected from at least one of dimethyl 2,5-furandicarboxylate, diethyl 2,5-furandicarboxylate, dipropyl 2,5-furandicarboxylate and dibutyl 2,5-furandicarboxylate.

[0033] Optionally, the organic solvent and the aqueous phase form a two-phase system.

[0034] Optionally, the organic solvent is selected from at least one of tetrahydrofuran, dioxane, cyclohexane, methyl isobutyl ketone and butanol.

[0035] Optionally, the aqueous phase is an aqueous solution of alkali metal halide.

[0036] Optionally, the alkali metal halide in the aqueous solution of alkali metal halide is selected from at least one of sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide and potassium iodide.

[0037] Optionally, the mass of the component I is 1-10% of the mass of the carbohydrate compound.

[0038] Optionally, the mass of component I is independently selected from any value of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% of the mass of the carbohydrate compound or a range between any two of the above values.

[0039] Optionally, the mass of the component II is 1-10% of the mass of the carbohydrate compound.

[0040] Optionally, the mass of component II is independently selected from any value of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% of the mass of the carbohydrate compound, or a range between any two of the above values.

[0041] Optionally, when other organic solvents are used, the mass ratio of the alcohol compound to the sugar compound is 1:1 to 3:1.

[0042] Optionally, when other organic solvents are used, the mass ratio of the alcohol compound to the sugar compound is independently selected from any value of 1:1, 1.5:1, 2:1, 2.5:1, 3:1 or a range between any two of the above.

[0043] Optionally, the mass percentage concentration of the carbohydrate compound in the mixture I is 10-25%.

[0044] Optionally, the mass percentage concentration of the carbohydrate compound in the mixture I is independently selected from any value of 10%, 15%, 20%, 25% or any range between the two.

[0045] Optionally, the mass percentage concentration of the sugar compound in the reaction system is 10-25%, wherein the reaction system comprises a two-phase system consisting of the sugar compound, a catalyst, an alcohol compound, an organic solvent and an aqueous phase.

[0046] Optionally, the mass ratio of the organic solvent to the aqueous phase is 1:2 to 2:1.

[0047] Optionally, the oxygen-containing atmosphere is selected from air atmosphere and / or oxygen atmosphere.

[0048] Optionally, the reaction temperature of the reaction I is 60-100° C., and the reaction time of the reaction I is 2-8 h.

[0049] Optionally, the temperature of the reaction I is independently selected from any value of 60°C, 70°C, 80°C, 90°C, 100°C or a range between any two of the above values.

[0050] Optionally, the reaction time I is independently selected from any value among 2h, 3h, 4h, 5h, 6h, 7h, 8h or a range between any two of the above.

[0051] Optionally, the pressure of the reaction I is 0.2-0.6 MPa.

[0052] Optionally, the pressure of the reaction I is independently selected from any value among 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, or any range between two values.

[0053] According to the present application, the catalyst is extremely important. When there is no catalyst or the catalyst activity is low, the conversion rate of the sugar compound is very low. Only when the catalyst activity and selectivity are high can a high conversion rate of the sugar compound and a high selectivity of 2,5-furandicarboxylic acid ester be obtained.

[0054] According to the present application, component I in the catalyst has multiple functions of catalyzing the hydrolysis of sucrose into glucose and fructose, the isomerization of glucose into fructose, and the dehydration of fructose into 5-hydroxymethylfurfural.

[0055] According to the present application, the role of the two-phase system consisting of an organic solvent and an aqueous phase is that: component I in the catalyst is dissolved in the aqueous phase, catalyzing the conversion of sugar compounds into 5-hydroxymethylfurfural, and the generated 5-hydroxymethylfurfural will not accumulate to cause side reactions such as polymerization, but will be immediately extracted into the organic phase and catalyzed by the organic hydrophobic catalyst (component II in the catalyst) dispersed in the organic phase to oxidatively esterify and convert into 2,5-furandicarboxylic acid ester; on the other hand, the sugar compound is dissolved in the aqueous phase and will not be catalyzed by the organic hydrophobic catalyst (component II in the catalyst) dispersed in the organic phase to oxidatively convert and produce by-products, thereby improving the selectivity of 2,5-furandicarboxylic acid ester.

[0056] The beneficial effects of this application include:

[0057] The present application provides a method for directly preparing 2,5-furandicarboxylic acid ester from a carbohydrate compound. The 5-hydroxymethylfurfural intermediate product generated by the reaction is directly oxidized and esterified to obtain 2,5-furandicarboxylic acid ester without separation, thereby reducing side reactions such as polymerization. The carbohydrate compound is dissolved in an aqueous phase and will not be catalyzed and oxidized by a hydrophobic oxidation catalyst dispersed in an organic phase to produce by-products. The method has the advantages of low cost, mild reaction conditions, and high product yield. DETAILED DESCRIPTION

[0058] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0059] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0060] Unless otherwise specified, conventional methods were used for testing.

[0061] The conversion rate and yield in the examples of this application are calculated as follows:

[0062]

[0063]

[0064] The present application adopts Waters 2695 liquid chromatography analysis to determine the conversion rate of sugar compounds and the yield of 2,5-furandicarboxylic acid ester.

[0065] Example 1

[0066] 100mL of ethanol-water solution (ethanol / water volume ratio of 5 / 1) containing 0.2mol / L Co(OAc)2 and 0.2mol / L Mn(OAc)2 was added dropwise to 200mL of 0.2mol / L hexamethylenediamine ethanol solution, stirred at 25°C for 6h, filtered, and the obtained solid was washed with distilled water and dried at 80°C for 12h to obtain 6.8g of hexamethylenediamine-complexed cobalt-manganese composite catalyst I.

[0067] Example 2

[0068] 100mL of 0.3mol / L Co(OAc)2 and 0.15mol / L Mn(OAc)2 ethanol-water solution (ethanol / water volume ratio is 3 / 1) was added dropwise to 300mL of 0.3mol / L octanediamine ethanol solution, stirred at 50°C for 24h, filtered, and the obtained solid was washed with distilled water and dried at 100°C for 6h to obtain 12.6g of octanediamine complexed cobalt-manganese composite catalyst II.

[0069] Example 3

[0070] 100mL of 0.1mol / L Co(OAc)2 and 0.1mol / L Mn(OAc)2 ethanol-water solution (ethanol / water volume ratio is 7 / 1) was added dropwise to 400mL of 0.1mol / L heptanediamine ethanol solution, stirred at 40°C for 12h, filtered, and the obtained solid was washed with distilled water and dried at 60°C for 24h to obtain 5.5g of heptanediamine complexed cobalt-manganese composite catalyst III.

[0071] Example 4

[0072] 100mL of ethanol-water solution (ethanol / water volume ratio of 5 / 1) containing 0.3mol / L Co(OAc)2 and 0.3mol / L Mn(OAc)2 was added dropwise to 300mL of 0.3mol / L ethanol solution of decanediamine, stirred at 25°C for 6h, filtered, and the obtained solid was washed with distilled water and dried at 80°C for 12h to obtain 13.5g of cobalt-manganese composite catalyst IV complexed with decanediamine.

[0073] Example 5

[0074] 100mL of ethanol-water solution (ethanol / water volume ratio of 5 / 1) containing 0.3mol / L Co(OAc)2 and 0.15mol / L Mn(OAc)2 was added dropwise to 300mL of 0.15mol / L dodecanediamine ethanol solution, stirred at 25°C for 6h, filtered, and the obtained solid was washed with distilled water and dried at 80°C for 12h to obtain 7.3g of dodecanediamine-complexed cobalt-manganese composite catalyst V.

[0075] Example 6

[0076] 10g of glucose, 1g of chromium chloride, 1g of hexamethylenediamine complexed cobalt-manganese composite catalyst I, 10g of ethanol, 10g of cyclohexane, and 10g of 20% sodium bromide aqueous solution were mixed, stirred, heated to 80°C, charged with oxygen to a pressure of 0.4MPa, and reacted for 4h. Liquid chromatography analysis showed that the glucose conversion rate was 100% and the yield of diethyl 2,5-furandicarboxylate was 68%.

[0077] Example 7

[0078] 10g of fructose, 0.1g of aluminum chloride, 0.1g of octanediamine complexed cobalt-manganese composite catalyst II, 10g of methanol, 20g of tetrahydrofuran, and 20g of 25% sodium chloride aqueous solution were mixed, stirred, heated to 60°C, charged with oxygen to a pressure of 0.2MPa, and reacted for 8h. Liquid chromatography analysis showed that the fructose conversion rate was 100% and the yield of dimethyl 2,5-furandicarboxylate was 81%.

[0079] Example 8

[0080] 10g sucrose, 0.2g indium chloride, 0.2g heptanediamine complexed cobalt-manganese composite catalyst III, 45g butanol as both a reaction substrate and an organic solvent, and 45g 15% sodium iodide aqueous solution were mixed, stirred, heated to 100°C, charged with oxygen to a pressure of 0.6MPa, and reacted for 2h. Liquid chromatography analysis showed that the sucrose conversion rate was 100% and the yield of dibutyl 2,5-furandicarboxylate was 75%.

[0081] Example 9

[0082] 10g of glucose, 0.3g of chromium chloride, 0.5g of cobalt-manganese composite catalyst IV complexed with decanediamine, 20g of propanol, 20g of dioxane, and 20g of 25% potassium bromide aqueous solution were mixed, stirred, heated to 90°C, charged with oxygen to a pressure of 0.4MPa, and reacted for 6h. Liquid chromatography analysis showed that the glucose conversion rate was 100% and the yield of dipropyl 2,5-furandicarboxylate was 62%.

[0083] Example 10

[0084] 10g of glucose, 0.5g of aluminum chloride, 0.3g of dodecanediamine complexed cobalt-manganese composite catalyst V, 20g of methanol, 25g of methyl isobutyl ketone, and 25g of 25% potassium iodide aqueous solution were mixed, stirred, heated to 70°C, charged with oxygen to a pressure of 0.3MPa, and reacted for 3h. Liquid chromatography analysis showed that the glucose conversion rate was 100% and the yield of dimethyl 2,5-furandicarboxylate was 66%.

[0085] Comparative Example 1

[0086] The difference between Comparative Example 1 and Example 6 is that no chromium chloride catalyst is used, and other reaction conditions are the same as those of Example 6. Liquid chromatography analysis shows that the glucose conversion rate is 17% and the yield of diethyl 2,5-furandicarboxylate is 10%.

[0087] Comparative Example 2

[0088] The difference between Comparative Example 2 and Example 6 is that the hexamethylenediamine-complexed cobalt-manganese composite catalyst I is not used, and other reaction conditions are the same as those in Example 6. Liquid chromatography analysis shows that the glucose conversion rate is 100% and the yield of diethyl 2,5-furandicarboxylate is 1%.

[0089] Comparative Example 3

[0090] The difference between Comparative Example 3 and Example 6 is that 24 g of cyclohexane is used as solvent, sodium bromide aqueous solution is not used, and other reaction conditions are the same as those of Example 6. Liquid chromatography analysis shows that the glucose conversion rate is 100% and the yield of diethyl 2,5-furandicarboxylate is 21%.

[0091] Comparative Example 4

[0092] The difference between Comparative Example 4 and Example 6 is that 24 g of 20% sodium bromide aqueous solution is used as solvent, cyclohexane is not used, and other reaction conditions are the same as those of Example 6. Liquid chromatography analysis shows that the glucose conversion rate is 100% and the yield of diethyl 2,5-furandicarboxylate is 19%.

[0093] Comparative Example 5

[0094] The difference between Comparative Example 5 and Example 1 is that 100 mL of ethanol-water solution (ethanol / water volume ratio of 5 / 1) containing 0.2 mol / L Co(OAc)2 and 0.2 mol / L Mn(OAc)2 is replaced by 100 mL of ethanol-water solution (ethanol / water volume ratio of 5 / 1) containing 0.2 mol / L Co(OAc)2, and other conditions are the same as in Example 1, to obtain 5.6 g of hexamethylenediamine-complexed cobalt catalyst VI.

[0095] Comparative Example 6

[0096] The difference between Comparative Example 6 and Example 1 is that 100 mL of ethanol-water solution (ethanol / water volume ratio of 5 / 1) containing 0.2 mol / L Co(OAc)2 and 0.2 mol / L Mn(OAc)2 is used instead of 100 mL of ethanol-water solution (ethanol / water volume ratio of 5 / 1) containing 0.2 mol / L Mn(OAc)2, and other conditions are the same as in Example 1, to obtain 5.5 g of hexamethylenediamine-complexed manganese catalyst VII.

[0097] Comparative Example 7

[0098] The difference between Comparative Example 7 and Example 6 is that 1g of hexamethylenediamine complexed cobalt catalyst VI is used instead of 1g of hexamethylenediamine complexed cobalt manganese composite catalyst I, and other conditions are the same as those in Example 6. Liquid chromatography analysis shows that the glucose conversion rate is 100% and the yield of diethyl 2,5-furandicarboxylate is 28%.

[0099] Comparative Example 8

[0100] The difference between Comparative Example 8 and Example 6 is that 1g of hexamethylenediamine complexed manganese catalyst VII is used instead of 1g of hexamethylenediamine complexed cobalt-manganese composite catalyst I, and other conditions are the same as those in Example 6. Liquid chromatography analysis shows that the glucose conversion rate is 100% and the yield of diethyl 2,5-furandicarboxylate is 2%.

[0101] The results of Examples 1-10 show that, under an oxygen-containing atmosphere, a mixture of a two-phase system consisting of a sugar compound, a catalyst, an alcohol, an organic solvent and an aqueous phase is reacted to obtain 2,5-furandicarboxylic acid ester; wherein the oxygen-containing atmosphere is an air atmosphere and / or an oxygen atmosphere; the catalyst comprises component I and component II; wherein component I is selected from at least one of aluminum chloride, indium chloride and chromium chloride, and component II is an organic hydrophobically modified cobalt-manganese composite catalyst, the conversion rate of the sugar compound can reach 100%, and the yield of 2,5-furandicarboxylic acid diester can reach up to more than 80%.

[0102] The results of Comparative Example 1 show that when the chromium chloride catalyst is not used, the conversion rate of glucose is very low. This is because chromium chloride plays an important role in the isomerization of glucose into fructose.

[0103] The results of Comparative Example 2 show that glucose can be completely converted using only chromium chloride catalyst without using the hexamethylenediamine-complexed cobalt-manganese composite catalyst I, but the yield of diethyl 2,5-furandicarboxylate is very low. This is because the hexamethylenediamine-complexed cobalt-manganese composite catalyst I plays an important role in the oxidative esterification of 5-hydroxymethylfurfural into diethyl 2,5-furandicarboxylate.

[0104] The results of Comparative Examples 3 and 4 show that when only cyclohexane or sodium bromide aqueous solution is used instead of the two-phase system consisting of cyclohexane and sodium bromide aqueous solution, the yield of diethyl 2,5-furandicarboxylate is very low, indicating that the two-phase system consisting of organic solvent and aqueous phase plays an important role in the reaction process.

[0105] The results of Comparative Examples 7 and 8 show that compared with the use of the hexamethylenediamine complexed cobalt-manganese composite catalyst, the yield of diethyl 2,5-furandicarboxylate is much lower when the hexamethylenediamine complexed cobalt catalyst or the hexamethylenediamine complexed manganese catalyst is used under the same conditions. It is speculated that the hexamethylenediamine complexed cobalt-manganese composite catalyst has a synergistic catalytic effect.

[0106] In summary, the present application reacts a mixture of a two-phase system consisting of a saccharide compound, a catalyst, an alcohol, an organic solvent and an aqueous phase under an oxygen-containing atmosphere to obtain 2,5-furandicarboxylic acid ester; wherein the oxygen-containing atmosphere is an air atmosphere and / or an oxygen atmosphere; the catalyst comprises component I and component II; wherein component I is selected from at least one of aluminum chloride, indium chloride and chromium chloride, and component II is an organic hydrophobically modified cobalt-manganese composite catalyst. The 5-hydroxymethylfurfural intermediate product generated by the reaction of the method is directly oxidized and esterified to obtain 2,5-furandicarboxylic acid ester without separation, thereby reducing side reactions such as polymerization; the saccharide compound is dissolved in the aqueous phase and will not be catalytically oxidized by the hydrophobic oxidation catalyst dispersed in the organic phase to produce by-products, which has the advantages of low cost, mild reaction conditions and high product yield.

[0107] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for directly preparing 2,5-furandicarboxylic acid ester from a carbohydrate compound, characterized in that: The preparation method comprises: Under an oxygen-containing atmosphere, a mixture I containing a sugar compound, a catalyst, an alcohol compound, an organic solvent, and an aqueous phase is reacted to obtain 2,5-furandicarboxylic acid ester; The catalyst comprises component I and component II; The component I is selected from at least one of aluminum chloride, indium chloride and chromium chloride; The component II is an organic hydrophobically modified cobalt-manganese composite catalyst.

2. The preparation method according to claim 1, characterized in that: The organic hydrophobically modified cobalt-manganese composite catalyst is a cobalt-manganese composite catalyst complexed with a long-chain fatty diamine; Preferably, the long-chain fatty diamine in the long-chain fatty diamine-complexed cobalt-manganese composite catalyst is selected from at least one of C6 to C12 fatty diamines.

3. The preparation method according to claim 1, characterized in that: The preparation method of the long-chain fatty diamine complexed cobalt-manganese composite catalyst comprises: A mixture II containing an ethanol-water solution of Co(OAc)2, an ethanol-water solution of Mn(OAc)2, and an ethanol solution of a long-chain fatty diamine is reacted to obtain a cobalt-manganese composite catalyst complexed with a long-chain fatty diamine; The long-chain fatty diamine in the ethanol solution of the long-chain fatty diamine is selected from at least one of C6 to C12 fatty diamines.

4. The preparation method according to claim 3, characterized in that: The C6-C12 fatty diamine is independently selected from at least one of hexamethylenediamine, heptamethylenediamine, octanediamine, nonamethylenediamine, decanediamine, undecanediamine, and dodecanediamine; Preferably, the concentration of the Co(OAc)2 ethanol-water solution is 0.1 to 0.3 mol / L; Preferably, the concentration of the ethanol-water solution of Mn(OAc)2 is 0.1 to 0.3 mol / L; Preferably, the molar ratio of Co(OAc)2 in the ethanol-water solution of Co(OAc)2 to Mn(OAc)2 in the ethanol-water solution of Mn(OAc)2 is 1:1 to 2:1; Preferably, the total amount of Co(OAc)2 and Mn(OAc)2 to the amount of long-chain fatty diamine is 1:1 to 1:2; Preferably, in the ethanol-water solution, the volume ratio of ethanol to water is 3:1 to 7:

1.

5. The preparation method according to claim 3, characterized in that: The temperature of the reaction II is 25 to 50° C., and the time of the reaction II is 6 to 24 hours.

6. The preparation method according to claim 1, characterized in that: The sugar compound is selected from at least one of fructose, glucose and sucrose; Preferably, the alcohol compound is selected from at least one of methanol, ethanol, propanol and butanol; Preferably, the 2,5-furandicarboxylic acid ester is at least one selected from dimethyl 2,5-furandicarboxylate, diethyl 2,5-furandicarboxylate, dipropyl 2,5-furandicarboxylate, and dibutyl 2,5-furandicarboxylate.

7. The preparation method according to claim 1, characterized in that: The organic solvent and the aqueous phase form a two-phase system; Preferably, the organic solvent is selected from at least one of tetrahydrofuran, dioxane, cyclohexane, methyl isobutyl ketone and butanol; Preferably, the aqueous phase is an aqueous solution of an alkali metal halide; Preferably, the alkali metal halide in the aqueous solution of alkali metal halide is selected from at least one of sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide and potassium iodide.

8. The preparation method according to claim 1, characterized in that: The mass of component I is 1 to 10% of the mass of the carbohydrate compound; Preferably, the mass of component II is 1 to 10% of the mass of the carbohydrate compound; Preferably, when other organic solvents are used, the mass ratio of the alcohol compound to the sugar compound is 1:1 to 3:1; Preferably, the mass percentage concentration of the carbohydrate compound in the mixture I is 10 to 25%; Preferably, the mass ratio of the organic solvent to the aqueous phase is 1:2 to 2:

1.

9. The preparation method according to claim 1, characterized in that: The oxygen-containing atmosphere is selected from an air atmosphere and / or an oxygen atmosphere.

10. The preparation method according to claim 1, characterized in that: The reaction temperature of the reaction I is 60-100° C., and the reaction time of the reaction I is 2-8 hours; Preferably, the pressure of the reaction I is 0.2-0.6 MPa.

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