2,5-furandicarboxylic acid and a method for its synthesis

Abstract

The application discloses 2,5-furan dicarboxylic acid and a synthesis method thereof, and belongs to the technical field of organic synthesis. The 2,5-furan dicarboxylic acid and the synthesis method thereof comprise the following steps: a mixture containing 2,5-furan dicarboxaldehyde and a solvent is reacted in an atmosphere containing an oxidant in the presence of a catalyst to obtain a reaction product containing 2,5-furan dicarboxylic acid; the catalyst comprises a carrier and an active component; the mass percentage content of the carrier and the active component in the catalyst is respectively as follows: the carrier is 85-95%, and the active component is 5-15%; the active component is at least one of cobalt, copper, ruthenium and iron; 2,5-furan dicarboxaldehyde is used as a raw material in the synthesis process, atomic economy is high, the production process is environment-friendly, meanwhile, the catalyst used in the reaction has high catalytic efficiency and good stability, the isomerization of the raw material HMF into other by-products can be avoided, and the total yield of the product is high.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a 2,5-furandicarboxylic acid and its synthesis method. Background Technology

[0002] 2,5-Furandicarboxylic acid is soluble in water under alkaline conditions and is a white powder under acidic conditions. It is a white crystalline solid or powder and is a renewable dicarboxylic acid monomer with an aromatic structure. It is used to prepare various alkyl-substituted or ester-based furan derivatives and to synthesize chiral catalysts, molecular recognition acceptors and polymer materials.

[0003] Currently, the most common production method for 2,5-furandicarboxylic acid (FDCA) is the oxidation of 2-methoxyfurfural (HMF). Cellulose is hydrolyzed to obtain glucose, which is isomerized to obtain fructose. Fructose is dehydrated to obtain HMF, and HMF is oxidized to obtain FDCA. This is the main research direction at present.

[0004] Chinese patent CN106795130 B discloses a method for converting hydroxymethylfurfural into a furan product including 2,5-furandicarboxylic acid. The method includes combining a certain amount of hydroxymethylfurfural with water to provide an aqueous solution containing at least about five weight percent of hydroxymethylfurfural, and combining the aqueous solution with an oxygen source in the presence of a heterogeneous ruthenium-based catalyst and under conditions effective for oxidizing hydroxymethylfurfural to a furan oxidation product including 2,5-furandicarboxylic acid, but in the absence of any solvent other than water for hydroxymethylfurfural or 2,5-furandicarboxylic acid.

[0005] Currently, the process of oxidizing HMF to prepare FDCA has disadvantages such as the easy isomerization of the raw material HMF into other byproducts and the complexity of the separation process, which limits its scale-up in engineering. Summary of the Invention

[0006] In view of the above situation, the present invention provides 2,5-furandicarboxylic acid and its synthesis method. The method utilizes a supported metal catalyst to catalytically oxidize 2,5-furandicarboxaldehyde to synthesize 2,5-furandicarboxylic acid. The synthesis route is characterized by high economy and abundant raw materials, which can avoid the isomerization of the raw material HMF into other by-products, and the separation process is simple.

[0007] To solve the above-mentioned technical problems, the first aspect of the present invention provides a method for synthesizing 2,5-furandicarboxylic acid, comprising the following steps:

[0008] In the presence of a catalyst, a mixture of 2,5-furandicarboxaldehyde and a solvent reacts in an oxidizing atmosphere to give a reaction product containing 2,5-furandicarboxylic acid.

[0009] The catalyst comprises a support and an active component; the mass percentages of the support and the active component in the catalyst are 90%–95% for the support and 5%–10% for the active component.

[0010] According to some embodiments of the present invention, the support is at least one of activated carbon, alumina, and 4A molecular sieve, and the active component is at least one of cobalt, copper, ruthenium, and iron. The active component in the catalyst of the present invention mainly exists in the form of oxides.

[0011] According to some embodiments of the present invention, the solvent is selected from at least one of water, methanol and a mixture of water; preferably, the volume ratio of methanol to water in the mixture of methanol and water is (1:5) to (1:10), for example 1:8.

[0012] According to some embodiments of the present invention, the oxidizing atmosphere is air or oxygen.

[0013] According to some embodiments of the present invention, the mass ratio of 2,5-furandicarboxaldehyde to the catalyst is (1-6):(0.1-0.3), for example 1:0.1, 6:0.17, 3:0.18, 3:0.13, 3:0.14, 3:0.15.

[0014] According to some embodiments of the present invention, the ratio of 2,5-furandicarboxaldehyde to solvent is (1-6) mol:1L, for example 1 mol:1L, 3 mol:1L, 6 mol:1L.

[0015] According to some embodiments of the present invention, the reaction conditions include: a reaction temperature of 60°C to 90°C, for example 60°C, 75°C, or 90°C; a reaction time of 3h to 6h, for example 3h or 6h; and a stirring rate of 500r / min to 600r / min, for example 500r / min or 600r / min.

[0016] According to some embodiments of the present invention, the synthesis method further includes a step of filtering the reaction product; specifically, the product solution is filtered using a filtration device, the solid product is collected, and the solid product is washed with deionized water.

[0017] According to some embodiments of the present invention, the preparation method of the catalyst includes the step of loading the active component onto a support; preferably, when loading the active component onto a support, the metal salt solution of the active component is mixed with the support, dried, and then calcined under an inactive atmosphere to obtain the catalyst.

[0018] According to some embodiments of the present invention, the catalyst has a specific surface area of ​​300 m². 3 / g~500m 3 / g, with a particle size of 40μm~90μm.

[0019] According to some embodiments of the present invention, the mass ratio of the metal salt of the active component to the carrier in the metal salt solution of the active component is (3-20):(20-25), for example 3.2:20, 4.1:20, 4.8:22, 15.3:25, 16.8:20, 19.7:20, 16.1:20, 15.3:20, 17.8:20; preferably, the mass concentration of the metal salt solution of the active component is 10%-20%, more preferably 15%; more preferably, the metal salt solution of the active component is at least one selected from copper nitrate solution, ferric nitrate solution, ruthenium nitrate solution, and cobalt nitrate solution.

[0020] According to some embodiments of the present invention, the mixing conditions include: a stirring rate of 500 r / min to 700 r / min, for example 600 r / min, a mixing time of 1 h to 3 h, for example 2 h, and a mixing temperature of 20 °C to 30 °C, for example 20 °C.

[0021] According to some embodiments of the present invention, the mixing process further includes a settling step; preferably, the settling time is 2 hours.

[0022] According to some embodiments of the present invention, the drying conditions include: a temperature of 110°C to 150°C, for example 120°C, and a time of 2h to 3h, for example 2h.

[0023] According to some embodiments of the present invention, the inactive atmosphere is at least one of nitrogen and argon.

[0024] According to some embodiments of the present invention, the calcination conditions include: a temperature of 250°C to 400°C, for example 300°C, and a time of 4h to 5h, for example 4h.

[0025] In this invention, the synthetic route for synthesizing 2,5-furandicarboxylic acid is as follows:

[0026]

[0027] This approach utilizes a highly efficient and stable supported metal catalyst in an air or oxygen atmosphere. The preferred active metal component in this supported metal catalyst is at least one of cobalt, copper, ruthenium, and iron, which have shown superior performance compared to other metals during the experimental screening process.

[0028] A second aspect of the present invention provides 2,5-furandicarboxylic acid obtained by the above-described synthesis method.

[0029] Beneficial effects:

[0030] This invention opens up a synthetic route for 2,5-furandicarboxylic acid. The synthesis process uses 2,5-furandicarboxaldehyde as a raw material, which has high atom economy and ensures that the production process is environmentally friendly. At the same time, the catalyst used in this reaction has high catalytic efficiency and good stability, which can avoid the isomerization of the raw material HMF into other by-products, resulting in a high overall product yield.

[0031] The catalyst preparation method described in this invention is simple, convenient for large-scale preparation, and can be used in industrial production devices such as fixed fluidized beds and reaction vessels;

[0032] The synthesis process of 2,5-furandicarboxylic acid described in this invention is an oxidation reaction, which uses air or oxygen to oxidize the aldehyde group to the carboxyl group. The process does not require the participation of other complex oxidizing additives. Moreover, the reaction conditions are simple, the operation is convenient, the reaction raw materials are readily available, and the product is easy to extract, which has potential industrial application prospects. Attached Figure Description

[0033] Figure 1 This is a SEM image of the cobalt / activated carbon catalyst prepared in Example 1 of the present invention.

[0034] Figure 2 This is a SEM image of the cobalt / activated carbon catalyst prepared in Example 2 of the present invention.

[0035] Figure 3 This is a SEM image of the cobalt / activated carbon catalyst prepared in Example 3 of the present invention.

[0036] Figure 4 This is the 1H-NMR characterization of 2,5-furandicarboxylic acid prepared in Example 1 of this invention.

[0037] Figure 5 The 13C-NMR characterization of 2,5-furandicarboxylic acid prepared in Example 1 of this invention. Detailed Implementation

[0038] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to these embodiments.

[0039] The reactor used in this invention is a common type of reactor on the market, with an operating temperature range of 10℃ to 350℃, such as a reaction vessel with a stirrer.

[0040] The drying oven used in this invention was purchased from Tianjin Zhonghuan Experimental Electric Furnace Co., Ltd., model ZK-38C.

[0041] The muffle furnace used in this invention was purchased from Tianjin Zhonghuan Experimental Electric Furnace Co., Ltd., model SX-G36123.

[0042] The SEM images of the catalyst described in this invention were taken using a scanning electron microscope (SEM) of the Quattro type, manufactured by FER.

[0043] In this invention, the carbon / hydrogen spectrum characterization of 2,5-furandicarboxylic acid was obtained by nuclear magnetic resonance (NMR) analysis using an Agilent ProPulse NMR spectrometer.

[0044] The activated carbon used in this invention was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with a purity of 98%.

[0045] The 4A molecular sieve used in this invention was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a pore size of 0.55nm to 0.7nm.

[0046] The alumina used in this invention was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of 99.9%.

[0047] In this invention, 2,5-furandicarboxaldehyde was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with a purity of 99%.

[0048] In this invention, the purity of 2,5-furandicarboxylic acid was determined using a high-performance liquid chromatography (HPLC) system with acetonitrile and water as the mobile phase at a flow rate of 3 ml / min and a UV detector.

[0049] The yield of 2,5-furandicarboxylic acid in this invention is calculated as the molar mass of the product (2,5-furandicarboxylic acid) / the molar mass of the raw material (2,5-furandicarboxaldehyde).

[0050] Example 1

[0051] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0052]

[0053] (1) Catalyst preparation

[0054] 3.2 g of cobalt nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a cobalt / activated carbon catalyst. The cobalt mass fraction of the cobalt / activated carbon catalyst was 8%. SEM images of the cobalt / activated carbon catalyst are shown below. Figure 1 The catalyst has a specific surface area of ​​320 m². 3 / g, the average particle size of the catalyst is 60μm.

[0055] (2) Synthesis of 2,5-furandicarboxylic acid

[0056] A 1 mol / L solution of 2,5-furandicarboxaldehyde was prepared by adding 124 g (1 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 12.5 g of the cobalt / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 60 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, and a total of 149.7 g of white 2,5-furandicarboxylic acid was obtained. The purity of the 2,5-furandicarboxylic acid product was 98.1%, and the yield was 96.0%.

[0057] The carbon / hydrogen spectral characterization of 2,5-furandicarboxylic acid is shown above. Figure 4 and Figure 5 , Figure 4 The carbon spectral characterization of 2,5-furandicarboxylic acid is as follows: 1 H-NMR (500MHz, CDCl3) δ12.56(s,2H), 7.48(s,2H), 2.90(s,1H), Figure 5 The 1H NMR spectrum of 2,5-furandicarboxylic acid was characterized as follows: 13 C-NMR (101MHz, CDCl3) δ171.3, 139.2, 130.3, 27.7.

[0058] Example 2

[0059] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0060]

[0061] (1) Catalyst preparation

[0062] 4.1 g of copper nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a copper / activated carbon catalyst. The copper mass fraction in the copper / activated carbon catalyst was 10%. SEM images of the copper / activated carbon catalyst are shown below. Figure 2 The catalyst has a specific surface area of ​​350 m². 3 / g, the average particle size of the catalyst is 70μm.

[0063] (2) Synthesis of 2,5-furandicarboxylic acid

[0064] A 6 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 744.3 g (6 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 21.3 g of the aforementioned copper / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 90 °C. The reaction was stopped after 3 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 879.8 g of white 2,5-furandicarboxylic acid with a purity of 98.0% and a yield of 94.0%.

[0065] Example 3

[0066] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0067]

[0068] (1) Catalyst preparation

[0069] 4.8 g of ferric nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 22 g of 4A molecular sieve (pore size 0.55 nm–0.7 nm) was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20 °C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120 °C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300 °C for 4 hours under a nitrogen atmosphere to obtain an iron / activated carbon catalyst. The iron content in the iron / activated carbon catalyst was 8% (w / w). SEM images of the iron / activated carbon catalyst are shown below. Figure 3 The catalyst has a specific surface area of ​​400 m². 3 / g, the average particle size of the catalyst is 80μm.

[0070] (2) Synthesis of 2,5-furandicarboxylic acid

[0071] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 22.5 g of the aforementioned iron / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 457.3 g of white 2,5-furandicarboxylic acid with a purity of 98.0% and a yield of 97.7%.

[0072] Example 4

[0073] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0074]

[0075] (1) Preparation of catalyst

[0076] 15.3 g of ruthenium nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 25 g of alumina was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. The dried solid was then calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a ruthenium / activated carbon catalyst. The ruthenium mass fraction in the ruthenium / alumina catalyst was 5%, and the specific surface area of ​​the catalyst was 380 m². 3 / g, the average particle size of the catalyst is 45μm.

[0077] (2) Synthesis of 2,5-furandicarboxylic acid

[0078] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 15.6 g of the above-mentioned ruthenium / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set at 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, and a total of 461.7 g of white 2,5-furandicarboxylic acid was obtained. The purity of 2,5-furandicarboxylic acid was 98%, and the yield was 98.7%.

[0079] Example 5

[0080] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0081]

[0082] (1) Preparation of catalyst

[0083] A 15% (w / w) solution was prepared by dissolving 8.3g of ruthenium nitrate hexahydrate and 8.5g of ferric nitrate hexahydrate in water. Then, 20g of activated carbon was added to the solution, and the mixture was stirred at 600 rpm for 2 hours at 20°C until homogeneous. After settling for 2 hours, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a ruthenium-iron / activated carbon catalyst. The catalyst contained 10% ruthenium and 5% iron by mass, and had a specific surface area of ​​450 m². 3 / g, the average particle size of the catalyst is 62μm.

[0084] (2) Synthesis of 2,5-furandicarboxylic acid

[0085] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 16.8 g of the aforementioned ruthenium-iron / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 600 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 453.8 g of white 2,5-furandicarboxylic acid with a purity of 98% and a yield of 97.0%.

[0086] Example 6

[0087] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0088]

[0089] (1) Preparation of catalyst

[0090] 10.2 g of ruthenium nitrate hexahydrate and 9.5 g of copper nitrate hexahydrate were dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution, and the mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a ruthenium-copper / activated carbon catalyst. The ruthenium mass fraction of the catalyst was 8%, and the copper mass fraction was 7%. The specific surface area of ​​the catalyst was 400 m². 3 / g, the average particle size of the catalyst is 53μm.

[0091] (2) Synthesis of 2,5-furandicarboxylic acid

[0092] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 15.6 g of the aforementioned ruthenium-copper activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 600 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 448.8 g of white 2,5-furandicarboxylic acid with a purity of 98% and a yield of 95.9%.

[0093] Example 7

[0094] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0095]

[0096] (1) Preparation of catalyst

[0097] A 15% (w / w) solution was prepared by dissolving 8.3 g of ruthenium nitrate hexahydrate and 7.8 g of cobalt nitrate hexahydrate in water. Then, 20 g of activated carbon was added to the solution, and the mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After settling for 2 hours, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a ruthenium-cobalt / activated carbon catalyst. The ruthenium mass fraction of the catalyst was 7.9%, and the cobalt mass fraction was 6.5%. The specific surface area of ​​the catalyst was 460 m². 3 / g, the average particle size of the catalyst is 86μm.

[0098] (2) Synthesis of 2,5-furandicarboxylic acid

[0099] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 15.6 g of the aforementioned ruthenium-cobalt / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 445.1 g of white 2,5-furandicarboxylic acid with a purity of 98% and a yield of 95.1%.

[0100] Example 8

[0101] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0102]

[0103] (1) Preparation of catalyst

[0104] 7.8 g of ferric nitrate hexahydrate and 7.5 g of copper nitrate hexahydrate were dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. The dried solid was then calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain an iron-copper / activated carbon catalyst. The iron-copper / activated carbon catalyst contained 6.5% (w / w) iron and 7.2% (w / w) copper by mass, and had a specific surface area of ​​390 m². 3 / g, the average particle size of the catalyst is 49μm.

[0105] (2) Synthesis of 2,5-furandicarboxylic acid

[0106] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 18.6 g of the aforementioned iron-copper / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 600 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 451.1 g of white 2,5-furandicarboxylic acid with a purity of 98% and a yield of 96.4%.

[0107] Example 9

[0108] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0109]

[0110] (1) Preparation of catalyst

[0111] A 15% (w / w) solution was prepared by dissolving 9.3 g of cobalt nitrate hexahydrate and 8.5 g of copper nitrate hexahydrate in water. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After settling for 2 hours, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a cobalt-copper / activated carbon catalyst. The cobalt mass fraction of the catalyst was 6.3%, and the copper mass fraction was 7.4%. The specific surface area of ​​the catalyst was 430 m². 3 / g, the average particle size of the catalyst is 56μm.

[0112] (2) Synthesis of 2,5-furandicarboxylic acid

[0113] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 16.2 g of the cobalt-copper / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, and a total of 453.0 g of white 2,5-furandicarboxylic acid was obtained. The purity of 2,5-furandicarboxylic acid was 98%, and the yield was 96.8%.

[0114] Example 10

[0115] This embodiment provides a method for synthesizing 2,5-furandicarboxylic acid.

[0116]

[0117] (1) Preparation of catalyst

[0118] 8.3 g of ferric nitrate hexahydrate and 7.8 g of cobalt nitrate hexahydrate were dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain an iron-cobalt / activated carbon catalyst. The iron-cobalt / activated carbon catalyst contained 7.3% (w / w) iron and 6.8% (w / w) cobalt, and had a specific surface area of ​​460 m². 3 / g, the average particle size of the catalyst is 77μm.

[0119] (2) Synthesis of 2,5-furandicarboxylic acid

[0120] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 15.6 g of the aforementioned iron-cobalt / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 600 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 75 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 444.1 g of white 2,5-furandicarboxylic acid with a purity of 98% and a yield of 94.9%.

[0121] Comparative Example 1

[0122] This comparative example provides a method for synthesizing 2,5-furandicarboxylic acid.

[0123]

[0124] (1) Preparation of catalyst

[0125] 1.6 g of cobalt nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a cobalt / activated carbon catalyst. The cobalt mass fraction of the catalyst was 4%, and the specific surface area of ​​the catalyst was 320 m². 3 / g, the average particle size of the catalyst is 60μm.

[0126] (2) Synthesis of 2,5-furandicarboxylic acid

[0127] A 1 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 124 g (1 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 12.5 g of the cobalt / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 60 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, and a total of 123.7 g of white 2,5-furandicarboxylic acid was obtained. The purity of the 2,5-furandicarboxylic acid product was 82.1%, and the yield was 79.3%.

[0128] Comparative Example 2

[0129] This comparative example provides a method for synthesizing 2,5-furandicarboxylic acid.

[0130]

[0131] (1) Preparation of catalyst

[0132] 9.6 g of cobalt nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a cobalt / activated carbon catalyst. The cobalt mass fraction of the catalyst was 24%, and the specific surface area of ​​the catalyst was 300 m². 3 / g, the average particle size of the catalyst is 44μm.

[0133] (2) Synthesis of 2,5-furandicarboxylic acid

[0134] A 3 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 375.6 g (3 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 12.5 g of the cobalt / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 60 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 409.9 g of white 2,5-furandicarboxylic acid with a purity of 89.4% and a yield of approximately 87.6%.

[0135] Comparative Example 3

[0136] This comparative example provides a method for synthesizing 2,5-furandicarboxylic acid.

[0137]

[0138] (1) Preparation of catalyst

[0139] 3.2 g of cobalt nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a cobalt / activated carbon catalyst. The cobalt mass fraction of the catalyst was 8%, and the specific surface area of ​​the catalyst was 320 m². 3 / g, the average particle size of the catalyst is 60μm.

[0140] (2) Synthesis of 2,5-furandicarboxylic acid

[0141] A 1 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 124 g (1 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 12.5 g of the cobalt / activated carbon catalyst was added. The reactor power was turned on, and the material was stirred at a rate of 400 r / min. The reactor was connected to the outside air, and the reaction temperature was set at 60 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, yielding a total of 146.9 g of white 2,5-furandicarboxylic acid. The purity of the 2,5-furandicarboxylic acid product was 95.1%, and the yield was 94.2%. It can be seen that the reduced stirring rate during the reaction reduced the contact interface between the reactants and the catalyst, thus affecting the yield.

[0142] Comparative Example 4

[0143] This comparative example provides a method for synthesizing 2,5-furandicarboxylic acid.

[0144]

[0145] (1) Preparation of catalyst

[0146] 3.2 g of cobalt nitrate hexahydrate was dissolved in water to prepare a 15% (w / w) solution. Then, 20 g of activated carbon was added to the solution. The mixture was stirred at 600 r / min for 2 hours at 20°C until homogeneous. After standing for 2 hours to precipitate, the turbid liquid was placed in a drying oven and dried at 120°C for 2 hours. Finally, the dried solid was calcined in a muffle furnace at 300°C for 4 hours under a nitrogen atmosphere to obtain a cobalt / activated carbon catalyst. The cobalt mass fraction of the catalyst was 8%, and the specific surface area of ​​the catalyst was 320 m². 3 / g, the average particle size of the catalyst is 60μm.

[0147] (2) Synthesis of 2,5-furandicarboxylic acid

[0148] A 1 mol / L 2,5-furandicarboxaldehyde solution was prepared by adding 124 g (1 mol) of 2,5-furandicarboxaldehyde to a 1 L aqueous solution. Then, 12.5 g of the cobalt / activated carbon catalyst was added, the reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set at 20 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, and a total of 101.5 g of white 2,5-furandicarboxylic acid was obtained. The purity of the 2,5-furandicarboxylic acid product was 64.3%, and the yield was 65.1%. It can be seen that if the reaction temperature is too low, the yield and purity will be affected.

[0149] Comparative Example 5

[0150] This comparative example provides a method for synthesizing 2,5-furandicarboxylic acid.

[0151] 124 g (1 mol) of 2,5-furandicarboxaldehyde was added to 1 L of aqueous solution to prepare a 1 mol / L 2,5-furandicarboxaldehyde solution. The reactor power was turned on, and the material was stirred at a rate of 500 r / min. The reactor was connected to the outside air, and the reaction temperature was set to 60 °C. The reaction was stopped after 6 h. After cooling the reaction product to 25 °C, the reaction solution was filtered, and a total of 33.3 g of white 2,5-furandicarboxylic acid was obtained. The purity of the 2,5-furandicarboxylic acid product was 31.6%, and the yield was 21.3%.

[0152] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for synthesizing 2,5-furandicarboxylic acid, characterized in that, Includes the following steps: In the presence of a catalyst, a mixture containing 2,5-furandicarboxaldehyde and a solvent is reacted in an oxidizing atmosphere to give a reaction product containing 2,5-furandicarboxylic acid. The catalyst comprises a support and an active component; the mass percentages of the support and the active component in the catalyst are respectively: 85%–95% for the support and 5%–15% for the active component. The carrier is at least one of activated carbon, alumina, and 4A molecular sieve; The active component is at least one of cobalt, copper, ruthenium, and iron; The reaction conditions include: a reaction temperature of 60℃~90℃ and a stirring rate of 500r / min~600r / min.

2. The synthesis method according to claim 1, characterized in that, The solvent is at least one of water, methanol, and a mixture of water.

3. The synthesis method according to claim 2, characterized in that, The volume ratio of methanol to water in the methanol-water mixture is (1:5) to (1:10).

4. The synthesis method according to any one of claims 1-3, characterized in that, The oxidizing atmosphere is air or oxygen; And / or, the mass ratio of the 2,5-furandicarboxaldehyde to the catalyst is (1-6):(0.1-0.3); And / or, the ratio of 2,5-furandicarboxaldehyde to solvent is (1-6) mol: 1L.

5. The synthesis method according to any one of claims 1-3, characterized in that, The reaction conditions include a reaction time of 3 to 6 hours.

6. The synthesis method according to any one of claims 1-3, characterized in that, The synthesis method further includes a step of filtering the reaction product.

7. The synthesis method according to any one of claims 1-3, characterized in that, The method for preparing the catalyst includes the step of loading the active component onto a support.

8. The synthesis method according to claim 7, characterized in that, When the active component is supported on a support, the metal salt solution of the active component is mixed with the support, dried, and then calcined under an inactive atmosphere to obtain the catalyst. And / or, the catalyst has a specific surface area of ​​300 m². 3 / g~500m 3 / g, with a particle size of 40μm~90μm.

9. The synthesis method according to claim 8, characterized in that, The mass ratio of the metal salt of the active component to the carrier in the metal salt solution of the active component is (3-20):(20-25). And / or, the mass concentration of the metal salt solution of the active component is 10% to 20%.

10. The synthesis method according to claim 9, characterized in that, The metal salt solution of the active component is at least one of copper nitrate solution, ferric nitrate solution, ruthenium nitrate solution, and cobalt nitrate solution.

11. The synthesis method according to claim 8, characterized in that, The mixing conditions include: a stirring rate of 500 r / min to 700 r / min, a mixing time of 1 h to 3 h, and a mixing temperature of 20 °C to 30 °C. And / or, the drying conditions include: a temperature of 110°C to 150°C and a time of 2 to 3 hours; And / or, the inactive atmosphere is at least one of nitrogen and argon; And / or, the calcination conditions include: a temperature of 250℃~400℃ and a time of 4h~5h; And / or, the mixing process may further include a step of allowing the mixture to settle.

12. The synthesis method according to claim 11, characterized in that, The settling time is 1-3 hours.

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