Preparation method for synthesizing 2, 5-furandicarboxylic acid through oxidation of 2, 5-furandimethanol

Abstract

The invention discloses a preparation method for synthesizing 2, 5-furandicarboxylic acid through oxidation of 2, 5-furandimethanol. The preparation method comprises the following steps: carrying out oxidation reaction on a mixed solution containing an oxidizing agent, an alkaline reagent, a magnetic oxide catalyst and 2, 5-furandimethanol at normal temperature and normal pressure to obtain 2, 5-furandicarboxylic acid; wherein the magnetic oxide catalyst is a non-noble metal oxide catalyst with both magnetism and catalytic oxidation activity, and the contained non-noble metal is selected from at least any one of Fe, Ni, Co and Ce elements. The preparation method disclosed by the invention has the advantages of high conversion rate of 2, 5-furandimethanol, high yield of 2, 5-furandicarboxylic acid, excellent stability, simplicity, no waste liquid, low energy consumption, suitability for large-scale production and the like; and the magnetic oxide catalyst is not easy to inactivate and can be regenerated through simple water washing, and the performance is not obviously reduced when the magnetic oxide catalyst is recycled.

Description

Technical Field

[0001] The invention belongs to the field of chemical technology research and development, and specifically relates to a preparation method for synthesizing 2,5-furandicarboxylic acid by oxidizing 2,5-furan dimethanol. Background Art

[0002] In order to actively respond to the problems of fossil energy depletion and increasingly severe ecological environment, researchers at home and abroad are committed to the in-depth development of renewable biomass resources to replace traditional energy or petrochemical raw materials. Bio-based carbohydrates can be converted into bio-based platform compounds 5-hydroxymethylfurfural through efficient catalytic technology, and then a variety of high-value furan chemicals are derived. Among them, 2,5-furandicarboxylic acid (FDCA), as an important biomass polymer monomer, can replace petroleum-based terephthalic acid to prepare bio-based polyester polyethylene furandicarboxylate, and has broad market prospects. At present, the main method for preparing FDCA is to use 5-hydroxymethylfurfural as raw material and use a heterogeneous catalytic system (mainly precious metal catalyst) for catalytic oxidation. However, due to the low melting point of 5-hydroxymethylfurfural itself, it needs to be stored at low temperature, and it is easy to have side reactions in alkaline solutions, producing a large number of by-products. These factors not only increase the control difficulty and product quality of the 5-hydroxymethylfurfural (HMF) oxidation process, but also limit the practical application of the process to a certain extent. Therefore, it is very necessary to select a raw material with stable chemical properties and convenient storage to synthesize FDCA. 2,5-Furan dimethanol (BHMF) is a selective hydrogenation product of 5-hydroxymethylfurfural. It is easy to store and has high stability. In particular, its degradation rate in alkaline solution is significantly lower than that of 5-hydroxymethylfurfural. If BHMF can be used as a raw material to develop an efficient catalytic process for synthesizing FDCA at room temperature and pressure, it is expected to achieve large-scale production and application of high-quality FDCA. Summary of the invention

[0003] The main purpose of the present invention is to provide a preparation method for synthesizing 2,5-furandicarboxylic acid by oxidizing 2,5-furan dimethanol, so as to overcome the shortcomings of the prior art.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0005] One aspect of the present invention provides a method for preparing 2,5-furandicarboxylic acid by oxidizing 2,5-furan dimethanol, which comprises: subjecting a mixed solution containing an oxidant, an alkaline reagent, a magnetic oxide catalyst, and 2,5-furan dimethanol to an oxidation reaction at room temperature and pressure to obtain 2,5-furandicarboxylic acid;

[0006] The magnetic oxide catalyst is a non-precious metal oxide catalyst having both magnetic properties and catalytic oxidation activity, the magnetic oxide catalyst includes a single-phase or two-phase structure, the magnetic oxide catalyst has mesopores, and the non-precious metal contained is selected from at least any one of Fe, Ni, Co, and Ce elements, and the mass fraction of the non-precious metal contained in the magnetic oxide catalyst is 10% to 50%.

[0007] Furthermore, the temperature of the oxidation reaction is 20° C. to 30° C., and the time of the oxidation reaction is 0.5 to 5 hours.

[0008] Compared with the prior art, the present invention has at least the following beneficial effects:

[0009] (1) The preparation method of the present invention has high BHMF conversion activity, high FDCA yield and excellent stability; after the oxidation reaction, the magnetic oxide catalyst and the reaction liquid can be separated by magnetic adsorption, and a high-purity FDCA product can be obtained after the reaction liquid is acidified; and the magnetic oxide catalyst is not easy to deactivate and can be regenerated by simple water washing, and the performance does not decrease significantly when it is recycled.

[0010] (2) The preparation method of the present invention can react at room temperature and pressure, and has the characteristics of being simple, free of waste liquid, low in energy consumption, and suitable for large-scale production.

[0011] (3) The magnetic oxide catalyst of the present invention has a mesoporous pore size, which can promote the contact between 2,5-furan dimethanol and the active center of the catalyst, improve the utilization rate of the active center of the catalyst, and enhance the conversion rate of BHMF. DETAILED DESCRIPTION

[0012] In view of the problems existing in the above-mentioned prior art, the inventors of the present invention have conducted extensive and in-depth research and provided a method for preparing 2,5-furandicarboxylic acid by oxidizing 2,5-furan dimethanol. The method mainly comprises the following steps: 2,5-furan dimethanol is catalytically oxidized over a magnetic oxide catalyst at room temperature and pressure to obtain 2,5-furandicarboxylic acid.

[0013] The technical solution, its implementation process and principle will be further explained as follows.

[0014] As one aspect of the technical solution of the present invention, a preparation method for synthesizing 2,5-furandicarboxylic acid by oxidizing 2,5-furan dimethanol is provided, comprising: subjecting a mixed solution containing an oxidant, an alkaline reagent, a magnetic oxide catalyst, and 2,5-furan dimethanol to an oxidation reaction at room temperature and pressure to obtain 2,5-furandicarboxylic acid;

[0015] The magnetic oxide catalyst is a non-precious metal oxide catalyst having both magnetic properties and catalytic oxidation activity, the magnetic oxide catalyst includes a single-phase or two-phase structure, the magnetic oxide catalyst has mesopores, and the non-precious metal contained is selected from at least any one of Fe, Ni, Co, and Ce elements, and the mass fraction of the non-precious metal contained in the magnetic oxide catalyst is 10% to 50%.

[0016] In some embodiments, the oxidation reaction temperature is 20° C. to 30° C., and the oxidation reaction time is 0.5 to 5 hours.

[0017] In some embodiments, the mass ratio of the 2,5-furan dimethanol to the magnetic oxide catalyst is 1:1 to 10:1.

[0018] In some embodiments, the mass ratio of the 2,5-furan dimethanol to the oxidant is 1:10-100.

[0019] In some embodiments, the mass ratio of the 2,5-furan dimethanol to the alkaline reagent is 1:1-10.

[0020] In some embodiments, the oxidant includes at least any one of sodium hypochlorite and hydrogen peroxide.

[0021] In some embodiments, the alkaline agent comprises sodium hydroxide.

[0022] In some embodiments, the pH value of the mixed solution is 7-14.

[0023] In some embodiments, the preparation method of 2,5-furan dimethanol to synthesize 2,5-furan dicarboxylic acid by oxidation includes: subjecting a mixed solution of the oxidant, alkaline reagent, magnetic oxide catalyst, and 2,5-furan dimethanol to an oxidation reaction at 20°C to 30°C and normal pressure for 0.5 to 5 hours; then adding hydrochloric acid to precipitate, and obtaining 2,5-furan dicarboxylic acid after filtering and drying.

[0024] In some embodiments, the method for preparing 2,5-furandicarboxylic acid by oxidizing 2,5-furan dimethanol further comprises: separating the magnetic oxide catalyst in the mixed solution by magnetic adsorption.

[0025] In some embodiments, the conversion rate of 2,5-furandimethanol is above 98%.

[0026] In some embodiments, the yield of 2,5-furandicarboxylic acid is above 90%.

[0027] In some embodiments, the product purity of the 2,5-furandicarboxylic acid is above 99%.

[0028] In some embodiments, the preparation method of the magnetic oxide catalyst comprises: mixing a non-precious metal salt aqueous solution with a hydroxide aqueous solution to obtain a precipitate, and calcining the precipitate to obtain a magnetic oxide catalyst; wherein the magnetic oxide catalyst has a mesoporous structure.

[0029] Furthermore, the diameter of the mesopore is 1 nm to 150 nm.

[0030] In some embodiments, the method for preparing the magnetic oxide catalyst further comprises: grinding the magnetic oxide catalyst and screening out the magnetic oxide catalyst having a particle size less than 150 μm.

[0031] Furthermore, the mass concentration of the non-precious metal salt aqueous solution is 1 g / L to 50 g / L.

[0032] Furthermore, the mass concentration of the hydroxide aqueous solution is 10 g / L to 40 g / L.

[0033] Furthermore, the mass ratio of the non-precious metal salt aqueous solution to the hydroxide aqueous solution is 10 to 1:1.

[0034] Furthermore, the mixing temperature is 5°C to 25°C.

[0035] Furthermore, the calcination temperature is 200°C to 500°C.

[0036] In some more specific embodiments, the preparation method of 2,5-furan dimethanol to synthesize 2,5-furandicarboxylic acid by oxidation specifically comprises the following steps: adding an oxidant, an alkaline reagent, a magnetic oxide catalyst and 2,5-furan dimethanol to a beaker in sequence, stirring at 20°C to 30°C and normal pressure, and performing an oxidation reaction for 0.5 to 5 hours; separating the catalyst from the reaction solution by using a magnet, adding hydrochloric acid to the obtained reaction clear solution to precipitate, and filtering and drying the precipitate to obtain FDCA.

[0037] The reaction route for the oxidation of 2,5-furan dimethanol to 2,5-furandicarboxylic acid is as follows:

[0038]

[0039] Specifically, the reaction mechanism of oxidizing 2,5-furan dimethanol to synthesize 2,5-furandicarboxylic acid in the present invention is as follows:

[0040] The oxidation mechanism of 2,5-furan dimethanol to 2,5-furandicarboxylic acid. In the first step, 2,5-furan dimethanol and sodium hypochlorite react under alkaline conditions, and the active oxygen species and the hydroxide ions in the solution grab the H atom on α-C and the hydrogen atom on the hydroxyl group to form an aldehyde group, and the by-product hydroxide ions make up for the consumption of the aforementioned hydroxide ions. The DFF formed by the first step of oxidation is still adsorbed on the oxygen vacancy, and then the second step of oxidation occurs: the hydroxide ions in the solution attack the aldehyde carbon atom to form a geminal diol alkoxide intermediate, and then the active oxygen species take the H atom on α-C to form a carboxyl group. At this point, the hydroxymethyl group on one side of the furan ring is completely oxidized to a carboxyl group. After the intermediate product FFCA is desorbed from the catalyst surface, the hydroxymethyl group on the other side is again adsorbed to the oxygen vacancy and activated, and 2,5-furandicarboxylic acid is finally obtained after an oxidation process similar to the above. This method can effectively avoid the formation of unstable intermediates HMF and inactive intermediates HMFCA.

[0041] In addition, from the perspective of the reaction system: as the temperature increases during the reaction, the carbon balance of the reaction system continues to decrease, but the reaction proceeds slowly at too low a temperature; from the perspective of the product: furandicarboxylic acid and its salts are prone to decarboxylation under high temperature conditions, so controlling the appropriate reaction time is beneficial to improving the selectivity of the product. Another inducement for decarboxylation is high temperature, and lowering the reaction temperature can effectively reduce the possibility of decarboxylation of the product.

[0042] In some more specific embodiments, the method for preparing the magnetic oxide catalyst specifically includes:

[0043] (1) mixing a non-noble metal salt aqueous solution and a hydroxide aqueous solution at a temperature of 5° C. to 25° C., and stirring to obtain a precipitate;

[0044] (2) calcining the filtered and washed precipitate at 200° C. to 500° C. to obtain a magnetic oxide;

[0045] (3) Grinding the prepared magnetic oxide, and selecting solid particles with a particle size less than 150 μm as magnetic oxide catalysts.

[0046] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with embodiment. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Those skilled in the art can make modifications or equivalent substitutions based on the understanding of the technical scheme of the present invention without departing from the spirit and scope of the technical scheme of the present invention, and all should be included in the protection scope of the present invention.

[0047] If the specific experimental steps or conditions are not specified in the embodiments, the operations or conditions of the conventional experimental steps described in the literature in the art can be carried out. If the manufacturer of the reagents or instruments used is not specified, they can be obtained commercially. Exemplarily, the raw materials and reagents in the embodiments of the present invention are purchased from Titan Group Chemical Reagent Co., Ltd., and the detection of reaction substrates and product concentrations and product purity is analyzed using an Agilent 1260 high performance liquid chromatograph. The commercial selection of the remaining raw materials and instruments not mentioned are all conventional selections and do not involve the core technical means of the present invention.

[0048] The conversion rate of 2,5-furan dimethanol and the yield of 2,5-furan dicarboxylic acid are calculated based on the carbon mole number. The conversion rate of BHMF, the yield of FDCA, and the purity of FDCA product in the reaction of 2,5-furan dimethanol oxidation to prepare 2,5-furan dicarboxylic acid are calculated as follows:

[0049]

[0050]

[0051] Example 1

[0052] Preparation of magnetic oxide catalysts:

[0053] Take 37g of ferric chloride hexahydrate and dissolve it in 90ml of deionized water, and put it in a beaker for later use; add 250mL of water and 10.5g of sodium hydroxide to a 1L jacketed reactor, and stir to dissolve; the stirring speed is 300rpm, and cooling circulating water is passed. The temperature in the kettle is monitored to keep the temperature in the kettle below 20°C, and the ferric chloride solution is added dropwise to the reactor at a flow rate of 20ml / min using a peristaltic pump. After the addition is complete, stirring is continued for 15min to obtain a ferric hydroxide solution; the reaction solution is filtered, and an equal amount of deionized water is added to wash the filter cake; the filter cake is taken out and dried at 45°C; after drying, it is calcined at 220°C for 4h to obtain an iron oxide catalyst, which is sample 1#.

[0054] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol:

[0055] Stir and dissolve 3.65 grams of sodium hydroxide and 160 milliliters of deionized water to prepare a sodium hydroxide solution. Add sodium hydroxide solution, 5 grams of catalyst, and 10 milliliters of 2,5-furan dimethanol aqueous solution (mass content 50%) to a 1-liter glass jacket reactor in sequence. Turn on the stirring, the speed is 300rpm, and the cooling circulating water is passed. After the temperature in the jacket reactor stabilizes at 25°C, add 300 milliliters of sodium hypochlorite solution (effective chlorine content 10%) to the glass jacket reactor and start timing. Sampling and analysis are carried out every 30 minutes, and the reaction is terminated in 120 minutes. After the reaction is completed, the catalyst is separated from the reaction solution with a magnet, 60 ml of hydrochloric acid is added to the reaction solution to adjust the pH to 1, it is filtered, and the filter cake is rinsed 3 times with an equal amount of deionized water, and the FDCA product is obtained after drying in an oven at 55°C.

[0056] Example 2

[0057] Preparation of magnetic oxide catalysts:

[0058] Take 30g of cobalt chloride hexahydrate and dissolve it in 90ml of deionized water, and put it in a beaker for later use; add 250mL of water and 10.5g of sodium hydroxide to a 1L jacketed reactor, and stir to dissolve; stir at a speed of 300rpm, pass cooling circulating water, use a peristaltic pump to drop the cobalt chloride solution into the reactor at a flow rate of 20ml / min, and monitor the temperature in the reactor to keep the temperature below 20°C. After the addition is completed, continue stirring for 15min to obtain a cobalt hydroxide solution; filter the reaction solution with a Buchner funnel, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 60°C; after drying, roast it at 435°C for 4h to obtain a cobalt oxide catalyst, which is sample 2#.

[0059] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is cobalt oxide catalyst sample 2#.

[0060] Example 3

[0061] Preparation of magnetic oxide catalysts:

[0062] Take 30g of nickel chloride hexahydrate and dissolve it in 90ml of deionized water, and put it in a beaker for later use; add 250mL of water and 10.5g of sodium hydroxide to a 1L jacketed reactor, and stir to dissolve; stir at a speed of 300rpm, pass cooling circulating water, use a peristaltic pump to add the nickel chloride solution dropwise to the reactor at a flow rate of 20m1 / min, and continue stirring for 10min after the addition is complete to obtain a nickel hydroxide solution; filter the reaction solution with suction, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 60°C; after drying, calcine at 350°C for 2h to obtain a nickel oxide catalyst, which is sample 3#.

[0063] Preparation of 2,5-furandicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is nickel oxide catalyst sample 3#.

[0064] Example 4

[0065] Preparation of magnetic oxide catalysts:

[0066] Take 57g of cerium chloride heptahydrate and dissolve it in 90ml of deionized water, and put it in a beaker for later use; add 250mL of water and 10.5g of sodium hydroxide to a 1L jacketed reactor, and stir to dissolve; stir at 300rpm, pass cooling circulating water, and monitor the temperature in the kettle; after the temperature in the kettle drops to 25°C and maintains for 5min, use a peristaltic pump to add the cerium chloride solution dropwise to the reactor at a flow rate of 20ml / min, and continue stirring for 15min after the addition is complete to obtain a cerium hydroxide solution; filter the reaction solution, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 60°C; after drying, calcine at 450°C for 6h to obtain a cerium oxide catalyst, which is sample 4#.

[0067] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is cerium oxide catalyst sample 4#.

[0068] Example 5

[0069] Preparation of magnetic oxide catalysts:

[0070] Take 60g of cobalt nitrate hexahydrate and dissolve it in 180ml of deionized water, and put it in a beaker for later use; add 500mL of water and 21g of sodium hydroxide to a 1L jacketed reactor, stir and dissolve at a speed of 300RPM, pass cooling circulating water, and monitor the temperature in the kettle; after the temperature in the kettle drops to 30°C and maintains for 5min, use a peristaltic pump to drop the cobalt chloride solution into the reactor at a flow rate of 20ml / min, and continue stirring for 10min after the dropwise addition is completed to obtain a cobalt hydroxide solution; filter the reaction solution with a Buchner funnel, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 40°C; after drying, roast it at 435°C for 4h to obtain a cobalt oxide catalyst, which is sample 5#.

[0071] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is cobalt oxide catalyst sample 5#.

[0072] Example 6

[0073] Preparation of magnetic oxide catalysts:

[0074] Take 60g of nickel nitrate hexahydrate and dissolve it in 180ml of deionized water, and put it in a beaker for later use; add 500mL of water and 21g of sodium hydroxide to a 1L jacketed reactor, stir and dissolve at a speed of 300RPM, pass cooling circulating water, and monitor the temperature in the kettle; after the temperature in the kettle drops to 30°C and maintains for 5min, use a peristaltic pump to add the cobalt chloride solution dropwise to the reactor at a flow rate of 20ml / min, and continue stirring for 10min after the addition is complete to obtain a cobalt hydroxide solution; filter the reaction solution with a Buchner funnel, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 60°C; after drying, calcine at 350°C for 2h to obtain a nickel oxide catalyst, which is sample 6#.

[0075] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is nickel oxide catalyst sample 6#.

[0076] Example 7

[0077] Preparation of magnetic oxide catalysts:

[0078] Take 30g of cobalt chloride hexahydrate and 30g of nickel chloride hexahydrate, dissolve them in 180ml of deionized water, mix them evenly, and put them in a beaker for later use; add 500mL of water and 21g of sodium hydroxide to a 1L jacketed reactor, stir and dissolve at a speed of 300RPM, pass cooling circulating water, and monitor the temperature in the kettle; after the temperature in the kettle drops to 30°C and maintains for 5min, use a peristaltic pump to add the cobalt chloride solution dropwise to the reactor at a flow rate of 20ml / min, and continue stirring for 10min after the addition is complete to obtain a cobalt hydroxide solution; filter the reaction solution with a Buchner funnel, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 50°C; after drying, calcine at 450°C for 3h to obtain a Co-Ni alloy catalyst, which is sample 7#.

[0079] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is Co-Ni alloy catalyst sample 7#.

[0080] Example 8

[0081] Preparation of magnetic oxide catalysts:

[0082] Take 25g of cobalt chloride hexahydrate and 45g of nickel chloride hexahydrate, dissolve them in 180ml of deionized water, mix them evenly, and put them in a beaker for later use; add 500mL of water and 21g of sodium hydroxide to a 1L jacketed reactor, stir and dissolve at a speed of 300RPM, pass cooling circulating water, and monitor the temperature in the kettle; after the temperature in the kettle drops to 30°C and maintains for 5min, use a peristaltic pump to drop the cobalt chloride solution into the reactor at a flow rate of 20ml / min, and continue stirring for 10min after the addition is complete to obtain a cobalt hydroxide solution; filter the reaction solution with a Buchner funnel, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 55°C; after drying, calcine at 335°C for 5h to obtain a Co-Ni alloy catalyst, which is sample 8#.

[0083] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is Co-Ni alloy catalyst sample 8#.

[0084] Example 9

[0085] Preparation of magnetic oxide catalysts:

[0086] Take 45g of cobalt chloride hexahydrate and 15g of nickel chloride hexahydrate, dissolve them in 180ml of deionized water, mix them evenly, and put them in a beaker for later use; add 500mL of water and 21g of sodium hydroxide to a 1L jacketed reactor, stir and dissolve at a speed of 300RPM, pass cooling circulating water, and monitor the temperature in the kettle; after the temperature in the kettle drops to 30°C and maintains for 5min, use a peristaltic pump to add the cobalt chloride solution dropwise to the reactor at a flow rate of 20ml / min, and continue stirring for 10min after the addition is complete to obtain a cobalt hydroxide solution; filter the reaction solution with a Buchner funnel, and add an equal amount of deionized water to wash the filter cake; take out the filter cake and dry it at 45°C; after drying, calcine at 550°C for 4h to obtain a Co-Ni alloy catalyst, which is sample 9#.

[0087] Preparation of 2,5-furan-dicarboxylic acid from 2,5-furan dimethanol: The operation steps are the same as those in Example 1, except that the catalyst is cobalt oxide catalyst sample 9#.

[0088] Example 10

[0089] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0090] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Sampling and analysis were performed every 30 minutes, and the reaction was terminated in 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0091] Embodiment 11

[0092] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0093] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 50 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Sampling and analysis were performed every 30 minutes, and the reaction was terminated in 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0094] Example 12

[0095] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0096] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 100 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Sampling and analysis were performed every 30 minutes, and the reaction was terminated in 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0097] Example 13

[0098] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0099] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1 liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 30°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Sampling and analysis were performed every 30 minutes, and the reaction was terminated in 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0100] Embodiment 14

[0101] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0102] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1 liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 20°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Sampling and analysis were performed every 30 minutes, and the reaction was terminated in 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0103] Embodiment 15

[0104] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0105] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. The reaction was terminated in 30 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0106] Example 16

[0107] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0108] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1 liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Samples were taken every 30 minutes for testing, and the reaction was terminated in 5 hours. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0109] Embodiment 17

[0110] Co-Ni alloy catalyst sample 7# cyclic catalytic oxidation of 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0111] Stir and dissolve 3.65 grams of sodium hydroxide and 160 milliliters of deionized water to prepare a sodium hydroxide solution. Add sodium hydroxide solution, 5 grams of 7# catalyst, and 10 milliliters of 2,5-furan dimethanol aqueous solution (mass content 50%) to a 1-liter glass jacket reactor in sequence. Turn on the stirring, the speed is 300rpm, and the cooling circulating water is passed. After the temperature in the jacket reactor stabilizes at 25°C, add 300 milliliters of sodium hypochlorite solution (effective chlorine content 10%) to the glass jacket reactor and start timing. Take samples and analyze every 30 minutes, and end the reaction in 120 minutes. Use a magnet to separate the catalyst from the reaction solution, and add an equal amount of deionized water to wash the catalyst once before continuing to apply the catalyst.

[0112] The application performance of 7# catalyst is shown in Table 2 below. The catalyst was reused 10 times, and BHMF could be completely converted. The purity of FDCA product could reach 99.8% to 99.9%, indicating that the magnetic oxide catalyst has good stability and potential industrial application prospects.

[0113] Comparative Example 1

[0114] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0115] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 10°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Sampling and analysis were performed every 30 minutes, and the reaction was terminated in 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0116] Comparative Example 2

[0117] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0118] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1 liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 40°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Sampling and analysis were performed every 30 minutes, and the reaction was terminated in 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0119] Comparative Example 3

[0120] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0121] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. The reaction was terminated after 15 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 min. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 h to obtain the furandicarboxylic acid product.

[0122] Comparative Example 4

[0123] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0124] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1 liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Samples were taken every 30 minutes for testing, and the reaction was terminated in 6 hours. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0125] Comparative Example 5

[0126] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0127] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 5 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Samples were taken every 30 minutes for testing, and the reaction was terminated after 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0128] Comparative Example 6

[0129] Co-Ni alloy catalyst sample 7# catalytically oxidizes 2,5-furan dimethanol to produce 2,5-furan-dicarboxylic acid:

[0130] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of 7# catalyst, and 120 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Samples were taken every 30 minutes for testing, and the reaction was terminated after 120 minutes. The catalyst was separated from the reaction solution with a magnet, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0131] Comparative Example 7

[0132] Pd / C catalyst catalytic oxidation of 2,5-furan dimethanol to prepare 2,5-furan-dicarboxylic acid:

[0133] 3.65 g of sodium hydroxide and 160 ml of deionized water were stirred and dissolved to prepare a sodium hydroxide solution. Sodium hydroxide solution, 5 g of Pd / C catalyst, and 10 ml of 2,5-furan dimethanol aqueous solution (mass content 50%) were added to a 1-liter glass jacket reactor in sequence. Stirring was started at a speed of 300 rpm, and cooling circulating water was introduced. After the temperature in the jacket reactor stabilized at 25°C, 300 ml of sodium hypochlorite solution (effective chlorine content 10%) was added to the glass jacket reactor and the timing was started. Samples were taken every 30 minutes for testing, and the reaction was terminated after 120 minutes. The catalyst was separated from the reaction solution with a Buchner funnel, and 25 mL of concentrated hydrochloric acid was added to the reaction solution at a drop rate of about 10 mL / min. After the addition, stirring was continued for 30 minutes. Subsequently, the mixed solution was filtered with a Buchner funnel and washed three times with deionized water. The filter cake was dried in an oven at 55°C for 5 hours to obtain the furandicarboxylic acid product.

[0134] Table 1 Performance of different catalysts for catalytic oxidation of 2,5-furan dimethanol to 2,5-furandicarboxylic acid

[0135]

[0136]

[0137] Table 2 Sample 7# catalyst cyclic catalysis of 2,5-furan dimethanol oxidation to prepare 2,5-furan-dicarboxylic acid

[0138]

[0139] Table 3 Comparison of products with different mass ratios of 2,5-furan dimethanol and magnetic oxide catalyst

[0140]

[0141] Table 4 Comparison of synthesis of 2,5-furandicarboxylic acid at different temperatures

[0142]

[0143]

[0144] Table 5 Comparison of synthesis of 2,5-furandicarboxylic acid at different reaction times

[0145]

[0146] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0147] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0148] Although the present invention has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made without departing from the spirit and scope of the present invention and that the elements of the embodiments may be replaced by substantial equivalents. In addition, many modifications may be made without departing from the scope of the present invention to adapt specific circumstances or materials to the teachings of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for performing the present invention, but it is intended that the present invention will include all embodiments within the scope of the appended claims. In addition, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A method for preparing 2,5-furandicarboxylic acid by oxidizing 2,5-furan dimethanol, characterized in that: include: A mixed solution containing an oxidant, an alkaline agent, a magnetic oxide catalyst, and 2,5-furan dimethanol is subjected to an oxidation reaction at room temperature and pressure to obtain 2,5-furandicarboxylic acid; The magnetic oxide catalyst is a non-precious metal oxide catalyst having both magnetic properties and catalytic oxidation activity, the magnetic oxide catalyst includes a single-phase or two-phase structure, the magnetic oxide catalyst has mesopores, and the non-precious metal contained is selected from at least any one of Fe, Ni, Co, and Ce elements, and the mass fraction of the non-precious metal contained in the magnetic oxide catalyst is 10% to 50%.

2. The preparation method according to claim 1, characterized in that: The temperature of the oxidation reaction is 20° C. to 30° C., and the time of the oxidation reaction is 0.5N5h.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the 2,5-furan dimethanol to the magnetic oxide catalyst is 1:1 to 10:1; And / or, the mass ratio of the 2,5-furan dimethanol to the oxidant is 1:10 to 100; And / or, the mass ratio of the 2,5-furan dimethanol to the alkaline reagent is 1:1-10.

4. The preparation method according to claim 1, characterized in that: The oxidant includes at least one of sodium hypochlorite and hydrogen peroxide; and / or, the alkaline agent comprises sodium hydroxide; And / or, the pH value of the mixed solution is 7-14.

5. The preparation method according to claim 1, characterized in that: include: The mixed solution of the oxidant, alkaline reagent, magnetic oxide catalyst and 2,5-furan dimethanol is subjected to oxidation reaction at 20°C to 30°C and normal pressure for 0.5 to 5 hours; then hydrochloric acid is added to precipitate, and 2,5-furandicarboxylic acid is obtained after filtering and drying.

6. The preparation method according to claim 1, characterized in that: The preparation method further comprises: separating the magnetic oxide catalyst in the mixed solution by magnetic adsorption.

7. The preparation method according to claim 1, characterized in that: The conversion rate of 2,5-furan dimethanol is above 98%; And / or, the yield of 2,5-furandicarboxylic acid is above 90%; And / or, the product purity of the 2,5-furandicarboxylic acid is above 99%.

8. The preparation method according to claim 1, characterized in that: The preparation method of the magnetic oxide catalyst comprises: mixing a non-noble metal salt aqueous solution with a hydroxide aqueous solution to obtain a precipitate, and calcining the precipitate to obtain the magnetic oxide catalyst; Preferably, the diameter of the mesopores in the magnetic oxide catalyst is 1 nm to 150 nm.

9. The preparation method according to claim 8, characterized in that: The method for preparing the magnetic oxide catalyst further comprises: grinding the magnetic oxide catalyst and screening out the magnetic oxide catalyst with a particle size less than 150 μm.

10. The preparation method according to claim 8, characterized in that: The mass concentration of the non-precious metal salt aqueous solution is 1g / L to 50g / L; And / or, the mass concentration of the hydroxide aqueous solution is 10 g / L to 40 g / L; and / or, the hydroxide comprises sodium hydroxide; And / or, the mass ratio of the non-precious metal salt aqueous solution to the hydroxide aqueous solution is 10-1:1; And / or, the mixing temperature is 5°C to 25°C; And / or, the calcination temperature is 200°C to 500°C.

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