A method for purifying 2,5-furandicarboxylic acid

Abstract

The application provides a purification method of 2,5-furan dicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities. The method of the application converts 5-formyl-furan-2-carboxylic acid with lower water solubility into 5-hydroxymethyl-furan-2-carboxylic acid with higher water solubility through high-selective hydrogenation, and then removes 5-hydroxymethyl-furan-2-carboxylic acid through water washing to achieve the purpose of purifying 2,5-furan dicarboxylic acid product. In the high-selective hydrogenation reaction of 5-formyl-furan-2-carboxylic acid, the method of the application uses a supported metal catalyst with low loading, has high catalytic activity and selectivity, and can realize selective hydrogenation of a small amount of 5-formyl-furan-2-carboxylic acid impurities in 2,5-furan dicarboxylic acid crude product.

Description

Technical Field

[0001] This invention belongs to the field of fine chemicals, specifically relating to a method for purifying 2,5-furandicarboxylic acid. Background Technology

[0002] Developing green and renewable biomass resources to replace traditional petroleum resources is a key focus of current social development and research. Among these, 2,5-furandicarboxylic acid (FDCA), synthesized from biomass resources, has a structure similar to terephthalic acid and is readily degradable in nature. It is mainly used to synthesize high-performance biodegradable polymers such as polyesters, nylons, and epoxy resins. In particular, polyethylene 2,5-furandicarboxylate (PEF), obtained by polymerizing 2,5-furandicarboxylic acid with ethylene glycol, exhibits superior mechanical and thermal properties and better gas barrier properties compared to polyethylene terephthalate (PET).

[0003] Currently, the main byproducts in the production of 2,5-furandicarboxylic acid include 2,5-dicarboxyfuran (DFF), 5-hydroxymethyl-furan-2-carboxylic acid (HFCA), and 5-formyl-furan-2-carboxylic acid (FFCA). Among these, 5-formyl-furan-2-carboxylic acid is a difficult impurity to remove from crude 2,5-furandicarboxylic acid because its solubility in various solvents is very close to that of 2,5-furandicarboxylic acid. This results in low purity of 2,5-furandicarboxylic acid and adversely affects its polymerization reaction.

[0004] Patent CN113121480A provides a method for purifying and refining 2,5-furandicarboxylic acid using a melt crystallization method. This method requires heating the material to above 290°C, resulting in high energy consumption and demanding equipment requirements. Patent CN110713474B provides a method for refining furandicarboxylic acid using a dissolution crystallization method, which involves the use and removal of large amounts of high-boiling-point solvents, similarly increasing energy consumption and method complexity. Therefore, improving the purity of 2,5-furandicarboxylic acid remains a challenge that requires further investigation by those skilled in the art. Summary of the Invention

[0005] A primary objective of this invention is to overcome at least one deficiency of the prior art and provide a method for purifying 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid. This method involves selectively hydrogenating the water-insoluble 5-formyl-furan-2-carboxylic acid to convert it into the water-insoluble 5-hydroxymethyl-furan-2-carboxylic acid, and then removing the 5-hydroxymethyl-furan-2-carboxylic acid by washing with water to achieve the purpose of purifying the 2,5-furandicarboxylic acid product.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for purifying 2,5-furandicarboxylic acid, comprising:

[0008] (1) In a mixed solvent containing organic solvent and water, 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurity is reacted with hydrogen in the presence of a hydrogenation catalyst, wherein the 5-formyl-furan-2-carboxylic acid is converted into 5-hydroxymethyl-furan-2-carboxylic acid.

[0009] (2) Filter the reaction solution obtained in step (1), separate the catalyst, remove the solvent, and obtain solid 2,5-furandicarboxylic acid containing 5-hydroxymethyl-furan-2-carboxylic acid impurity;

[0010] (3) Wash the 2,5-furandicarboxylic acid solid containing 5-hydroxymethyl-furan-2-carboxylic acid impurity obtained in step (2), dissolve the 5-hydroxymethyl-furan-2-carboxylic acid impurity in water, and the remaining solid is the purified 2,5-furandicarboxylic acid product.

[0011] The 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity can be derived from primary products or other processes during the production of 2,5-furandicarboxylic acid via the 5-hydroxymethylfurfural oxidation method.

[0012] In the 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity, the content of 5-formyl-furan-2-carboxylic acid is 0.1% to 30%, preferably 0.2% to 20%, and more preferably 0.5% to 10%.

[0013] In step (1), the hydrogenation catalyst is a supported metal catalyst, which includes a support and a metal supported on the support. The metal is one or more of Pd, Pt, Ru or Ir, preferably Pd or Pt.

[0014] In step (1), the metal loading in the supported metal catalyst is 0.05% to 2% based on the total mass of the support, preferably 0.1% to 1%, and more preferably 0.2% to 0.5%.

[0015] In step (1), the carrier is one or more of activated carbon, silicon dioxide, zirconium oxide or titanium dioxide.

[0016] In step (1), the mass ratio of the catalyst to the 5-formyl-furan-2-carboxylic acid impurity is 1:0.1-20, preferably 1:0.2-10, and more preferably 1:0.5-5.

[0017] In step (1), the organic solvent is selected from one or two of tetrahydrofuran, 1,4-dioxane, or dimethyl sulfoxide, preferably tetrahydrofuran and 1,4-dioxane. In the mixed solvent composed of the organic solvent and water, the mass ratio of the organic solvent to water is 5:1 to 0.5:1, preferably 3:1 to 1:1.

[0018] In the solution formed by the 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity and the mixed solvent composed of the organic solvent and water, the mass percentage of the 2,5-furandicarboxylic acid is 0.1% to 30%, preferably 0.5% to 20%, and more preferably 1% to 10%.

[0019] In step (1), the reaction temperature is 15℃~150℃, preferably 40℃~140℃, and more preferably 60℃~120℃. The reaction time is related to the amount of substrate, the amount of catalyst, and the reaction conditions, and is usually 1~20 hours, preferably 1~10 hours.

[0020] In step (1), the pressure of the hydrogen gas is 0.1 MPa to 4 MPa, preferably 0.5 MPa to 2 MPa.

[0021] In step (2), the filtration temperature is 20℃~150℃, preferably 50℃~120℃.

[0022] In step (3), the 2,5-furandicarboxylic acid solid containing 5-hydroxymethyl-furan-2-carboxylic acid impurities obtained in step (2) is washed multiple times with deionized water to fully dissolve the 5-hydroxymethyl-furan-2-carboxylic acid.

[0023] In step (3), the 2,5-furandicarboxylic acid product after purification has a recovery rate of more than 90% based on the mass of 2,5-furandicarboxylic acid in the raw material; and the 2,5-furandicarboxylic acid content in the purified 2,5-furandicarboxylic acid product is greater than 99%.

[0024] The inventors of this application unexpectedly discovered that 5-hydroxymethyl-furan-2-carboxylic acid has a significantly higher solubility in water than 2,5-furandicarboxylic acid and 5-formyl-furan-2-carboxylic acid. By selectively hydrogenating 5-formyl-furan-2-carboxylic acid to 5-hydroxymethyl-furan-2-carboxylic acid, this impurity can be removed by washing with water. Therefore, efficiently achieving the selective hydrogenation of small amounts of 5-formyl-furan-2-carboxylic acid impurities in crude 2,5-furandicarboxylic acid is of great significance.

[0025] In the hydrogenation reaction of 5-formyl-furan-2-carboxylic acid, this invention unexpectedly discovered that using a supported metal catalyst with a lower loading, while ensuring the catalyst has a certain ability to hydrogenate formyl groups to hydroxymethyl groups, limits the hydrogenation reduction of carboxyl groups in the substrate and the hydrogenation saturation process of unsaturated C=C double bonds on the furan ring. That is, it is possible to hydrogenate a small amount of 5-formyl-furan-2-carboxylic acid to 5-hydroxymethyl-furan-2-carboxylic acid while limiting the hydrogenation conversion of 2,5-furandicarboxylic acid, thus providing a basis for the subsequent removal of impurities and the purification of 2,5-furandicarboxylic acid products.

[0026] As can be seen from the above technical solution, the advantages and positive effects of the purification method for 2,5-furandicarboxylic acid proposed in this invention are as follows: under relatively mild conditions, 5-formyl-furan-2-carboxylic acid impurities that are difficult to remove by other methods can be efficiently converted into easily removable 5-hydroxymethyl-furan-2-carboxylic acid, thereby removing impurities through simple water washing and significantly improving the purity of 2,5-furandicarboxylic acid products. Detailed Implementation

[0027] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0028] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0029] Preparation Example 1

[0030] Preparation of 0.2% Pd / C supported noble metal catalyst:

[0031] 0.2 mL of a 0.1 mol / L PdCl2 solution and 3.0 mL of deionized water were mixed and stirred until homogeneous. Then, 1.00 g of activated carbon support was added to the mixture. After stirring and impregnation at room temperature for 10 hours, the water was evaporated, and then the mixture was dried in an oven at 110 °C for 12 hours to obtain the catalyst precursor. The Pd loading was 0.2% (mass percentage). The precursor prepared in the above steps was placed in a quartz tube and reduced at 500 °C for 3 hours in 20% H2 + N2 to obtain a supported 0.2% Pd / C catalyst.

[0032] Preparation Example 2

[0033] Preparation of 0.5% Pd / TiO2 supported noble metal catalyst:

[0034] 0.5 mL of a 0.1 mol / L PdCl2 solution and 3.0 mL of deionized water were mixed and stirred until homogeneous. Then, 1.00 g of TiO2 support was added to the mixture. After stirring and impregnation at room temperature for 10 hours, the water was evaporated, and then the mixture was dried in an oven at 110 °C for 12 hours to obtain the catalyst precursor. The Pd loading was 0.5% (mass percentage). The precursor prepared in the above steps was placed in a quartz tube and reduced at 500 °C for 3 hours in 20% H2 + N2 to obtain a supported 0.5% Pd / TiO2 catalyst.

[0035] Preparation Example 3

[0036] Preparation of 0.4% Pt / SiO2 supported noble metal catalyst:

[0037] 0.2 mL of a 0.1 mol / L H₂PtCl₆ solution and 3.0 mL of deionized water were mixed and stirred until homogeneous. Then, 1.00 g of SiO₂ support was added to the mixture. After stirring and impregnation at room temperature for 10 hours, the water was evaporated, and then the mixture was dried in an oven at 110 °C for 12 hours to obtain the catalyst precursor. The Pt loading was 0.4% (mass percentage). The precursor prepared in the above steps was placed in a quartz tube and reduced at 500 °C for 3 hours in 20% H₂ + N₂ to obtain a supported 0.4% Pt / SiO₂ catalyst.

[0038] Preparation Example 4

[0039] Preparation of supported noble metal catalysts with 1% Pd / C:

[0040] 1.0 mL of 0.1 mol / L PdCl2 solution and 3.0 mL of deionized water were mixed and stirred until homogeneous. Then, 1.00 g of activated carbon support was added to the mixture. After stirring and impregnation at room temperature for 10 hours, the water was evaporated, and then the mixture was dried in an oven at 110 °C for 12 hours to obtain the catalyst precursor. The Pd loading was 1% (mass percentage). The precursor prepared in the above steps was placed in a quartz tube and reduced at 500 °C for 3 hours in 20% H2 + N2 to obtain a supported 1% Pd / C catalyst.

[0041] Preparation Example 5

[0042] Preparation of supported noble metal catalysts with 3% Pd / C:

[0043] 3.0 mL of 0.1 mol / L PdCl2 solution and 3.0 mL of deionized water were mixed and stirred until homogeneous. Then, 1.00 g of activated carbon support was added to the mixture. After stirring and impregnation at room temperature for 10 hours, the water was evaporated, and then the mixture was dried in an oven at 110 °C for 12 hours to obtain the catalyst precursor. The Pd loading was 3% (mass percentage). The precursor prepared in the above steps was placed in a quartz tube and reduced at 500 °C for 3 hours in 20% H2 + N2 to obtain a supported 3% Pd / C catalyst.

[0044] Preparation Example 6

[0045] To better quantitatively investigate the reaction between 5-formyl-furan-2-carboxylic acid and 2,5-furandicarboxylic acid in this method, commercially available 2,5-furandicarboxylic acid and 5-formyl-furan-2-carboxylic acid reagents were mechanically mixed to prepare a 2,5-furandicarboxylic acid raw material containing 5-formyl-furan-2-carboxylic acid impurities.

[0046] Taking 2,5-furandicarboxylic acid with an impurity content of 10% as an example, 900 mg of 2,5-furandicarboxylic acid solid powder and 100 mg of 5-formyl-furan-2-carboxylic acid solid powder were weighed separately and then ground and mixed in a mortar to obtain 2,5-furandicarboxylic acid raw material with an impurity content of 10% of 5-formyl-furan-2-carboxylic acid.

[0047] Using this method, 2,5-furandicarboxylic acid raw materials with an impurity content of 1% and 5% of 5-formyl-furan-2-carboxylic acid can be prepared.

[0048] Example 1

[0049] This example illustrates the purification of 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities using the supported 0.2% Pd / C catalyst of Preparation Example 1 as the catalyst in step (1).

[0050] (1) 50 mg of the supported 0.2% Pd / C catalyst obtained in Preparation Example 1, 500 mg of 2,5-furandicarboxylic acid with an impurity content of 10% (i.e., containing 450 mg of 2,5-furandicarboxylic acid and 50 mg of 5-formyl-furan-2-carboxylic acid), 10 mL of dioxane, and 10 mL of water were added to the reactor. After H2 was introduced to replace the reactor four times, the reactor was stirred and heated under low pressure until the predetermined reaction temperature of 60°C was reached. H2 was introduced again to make the pressure inside the reactor 10 MPa. After the reaction was continued for 8 hours, the heating was stopped, and the reactor was opened at 60°C by depressurization.

[0051] (2) The reaction solution obtained in step (1) was filtered at 60°C. After separating the catalyst, the solvent was removed from the reaction solution by rotary evaporator to obtain solid 2,5-furandicarboxylic acid containing 5-hydroxymethyl-furan-2-carboxylic acid impurities.

[0052] (3) Wash the solid obtained in step (2) five times in a beaker with deionized water. After each washing, separate the aqueous phase from the solid by centrifugation. After drying and weighing the remaining solid, add a small amount of Na2CO3 aqueous solution to dissolve it and make up to 500 mL. Perform quantitative analysis using high performance liquid chromatography.

[0053] The remaining solid mass was determined to be 429 mg, of which 2,5-furandicarboxylic acid content was 99.9% and 5-formyl-furan-2-carboxylic acid content was 0.1%. That is, after treatment by this method, the recovery rate of 2,5-furandicarboxylic acid was (429 mg / 450 mg × 100%) 95.3%, and the purity was 99.9%.

[0054] Example 2

[0055] This example illustrates the purification of 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities using the supported 0.5% Pd / TiO2 catalyst of Preparation Example 2 as the catalyst in step (1).

[0056] (1) 50 mg of the supported 0.5% Pd / TiO2 catalyst obtained in Preparation Example 2, 1000 mg of 2,5-furandicarboxylic acid with an impurity content of 5% (i.e. containing 950 mg of 2,5-furandicarboxylic acid and 50 mg of 5-formyl-furan-2-carboxylic acid), 10 mL of dioxane, and 10 mL of water were added to the reactor. After H2 was introduced to replace the reactor four times, the reactor was stirred and heated under low pressure until the predetermined reaction temperature of 60°C was reached. H2 was introduced again to make the pressure inside the reactor 0.5 MPa. After the reaction was continued for 4 hours, the heating was stopped, the pressure was released, and the reactor was opened.

[0057] (2) Filter the reaction solution obtained in step (1) at 60°C. After separating the catalyst, remove the solvent from the reaction solution by rotary evaporator to obtain solid 2,5-furandicarboxylic acid containing 5-hydroxymethyl-furan-2-carboxylic acid impurity.

[0058] (3) Wash the solid obtained in step (2) five times in a beaker with deionized water. After each washing, separate the aqueous phase from the solid by centrifugation. After drying and weighing the remaining solid, add a small amount of Na2CO3 aqueous solution to dissolve it and make up to 500 mL. Perform quantitative analysis using high performance liquid chromatography.

[0059] The remaining solid mass was determined to be 929 mg, of which 2,5-furandicarboxylic acid content was 99.7% and 5-formyl-furan-2-carboxylic acid content was 0.3%. That is, after treatment by this method, the recovery rate of 2,5-furandicarboxylic acid was (929 mg / 950 mg × 100%) 97.8%, and the purity was 99.7%.

[0060] Example 3

[0061] This example illustrates the purification of 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities using the supported 0.4% Pt / SiO2 catalyst of Preparation Example 3 as the catalyst in step (1).

[0062] (1) 10 mg of the supported 0.4% Pt / SiO2 catalyst obtained in Preparation Example 3, 2000 mg of 2,5-furandicarboxylic acid with an impurity content of 1% (i.e. containing 1980 mg of 2,5-furandicarboxylic acid and 20 mg of 5-formyl-furan-2-carboxylic acid), 10 mL of dioxane, and 10 mL of water were added to the reactor. After H2 was introduced to replace the reactor four times, the reactor was stirred and heated under low pressure until the predetermined reaction temperature of 100°C was reached. H2 was introduced again to make the pressure inside the reactor 1.0 MPa. After the reaction was continued for 4 hours, the heating was stopped and the reactor was opened when the temperature dropped to 80°C.

[0063] (2) The reaction solution obtained in step (1) was filtered at 80°C. After separating the catalyst, the reaction solution was removed by a rotary evaporator to obtain solid 2,5-furandicarboxylic acid containing 5-hydroxymethyl-furan-2-carboxylic acid impurities.

[0064] (3) Wash the solid obtained in step (2) five times in a beaker with deionized water. After each washing, separate the aqueous phase from the solid by centrifugation. After drying and weighing the remaining solid, add a small amount of Na2CO3 aqueous solution to dissolve it and make up to 500 mL. Perform quantitative analysis using high performance liquid chromatography.

[0065] The remaining solid mass was determined to be 1942 mg, of which 2,5-furandicarboxylic acid content was 99.5% and 5-formyl-furan-2-carboxylic acid content was less than 0.5%. That is, after treatment by this method, the recovery rate of 2,5-furandicarboxylic acid was (1942 mg / 1980 mg × 100%) 98.1%, and the purity was 99.5%.

[0066] Example 4

[0067] This example illustrates the purification of 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities using the supported 0.2% Pd / C catalyst of Preparation Example 1 as the catalyst in step (1).

[0068] (1) 50 mg of the supported 0.2% Pd / C catalyst obtained in Preparation Example 1, 500 mg of 2,5-furandicarboxylic acid with an impurity content of 10% (i.e., containing 450 mg of 2,5-furandicarboxylic acid and 50 mg of 5-formyl-furan-2-carboxylic acid), 7 mL of tetrahydrofuran, and 3 mL of water were added to the reactor. After H2 was introduced to replace the reactor four times, the reactor was stirred and heated under low pressure until the predetermined reaction temperature of 100°C was reached. H2 was introduced again to make the pressure inside the reactor 2.0 MPa. After the reaction was continued for 4 hours, the heating was stopped and the reactor was opened when the temperature dropped to 50°C.

[0069] (2) Filter the reaction solution obtained in step (1) at 50°C. After separating the catalyst, remove the solvent from the reaction solution by rotary evaporator to obtain solid 2,5-furandicarboxylic acid containing 5-hydroxymethyl-furan-2-carboxylic acid impurity.

[0070] (3) Wash the solid obtained in step (2) five times in a beaker with deionized water. After each washing, separate the aqueous phase from the solid by centrifugation. After drying and weighing the remaining solid, add a small amount of Na2CO3 aqueous solution to dissolve it and make up to 500 mL. Perform quantitative analysis using high performance liquid chromatography.

[0071] The remaining solid mass was determined to be 416 mg, of which 2,5-furandicarboxylic acid content was 99.1% and 5-formyl-furan-2-carboxylic acid content was 0.9%. That is, after treatment by this method, the recovery rate of 2,5-furandicarboxylic acid was (416 mg / 450 mg × 100%) 92.4%, and the purity was 99.1%.

[0072] Example 5

[0073] The reaction was carried out according to the method of Example 1, except that the reaction temperature in step (1) was 100°C, the reaction pressure of H2 was 2.0 MPa, and the reaction time was 1 hour.

[0074] The remaining solid mass was determined to be 410 mg, of which 2,5-furandicarboxylic acid content was 99.3% and 5-formyl-furan-2-carboxylic acid content was 0.7%. That is, after treatment by this method, the recovery rate of 2,5-furandicarboxylic acid was (410 mg / 450 mg × 100%) 91.1%, and the purity was 99.3%.

[0075] Example 6

[0076] The reaction was carried out according to the method of Example 1, except that the catalyst used in step (1) was 50 mg of the supported 1% Pd / C catalyst obtained in Preparation Example 4, and the reaction time was 2 hours.

[0077] The remaining solid mass was determined to be 407 mg, of which 2,5-furandicarboxylic acid content was 99.8% and 5-formyl-furan-2-carboxylic acid content was 0.2%. That is, after treatment by this method, the recovery rate of 2,5-furandicarboxylic acid was (407 mg / 450 mg × 100%) 90.4%, and the purity was 99.8%.

[0078] Comparative Example 1

[0079] The reaction was carried out according to the method of Example 1, except that the catalyst used in step (1) was 50 mg of the supported 3% Pd / C catalyst obtained in Preparation Example 5, and the reaction time was 1 hour.

[0080] The remaining solid mass was determined to be 191 mg, of which 2,5-furandicarboxylic acid content was 99.9% and 5-formyl-furan-2-carboxylic acid content was 0.1%. That is, after treatment by this method, the recovery rate of 2,5-furandicarboxylic acid was (191 mg / 450 mg × 100%) 42.4%, and the purity was 99.9%.

[0081] It is evident that the purification method of this invention can successfully purify 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities, achieving a recovery rate of over 90% and a purity of over 99%. However, using the method of Comparative Example 1, when the metal loading in the catalyst exceeds the range defined in this invention, the catalyst's catalytic activity for the hydrogenation reduction of carboxyl groups and the hydrogenation saturation of the C=C double bond on the furan ring is significantly enhanced. This leads to a large conversion of 2,5-furandicarboxylic acid into other compounds with higher solubility, such as 2,5-tetrahydrofurandicarboxylic acid and 2,5-dihydroxymethyltetrahydrofuran, resulting in a substantial decrease in the recovery rate of 2,5-furandicarboxylic acid. This demonstrates that the catalyst loading has a significant effect on improving the recovery rate of 2,5-furandicarboxylic acid.

[0082] Those skilled in the art should note that the embodiments described in this invention are merely exemplary, and various other substitutions, changes, and improvements can be made within the scope of this invention. Therefore, this invention is not limited to the above embodiments, but is defined only by the claims.

Claims

1. A method for purifying 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities, characterized in that, include: (1) In a mixed solvent containing an organic solvent and water, 2,5-furandicarboxylic acid containing 5-formyl-furan-2-carboxylic acid impurities is reacted with hydrogen in the presence of a hydrogenation catalyst, wherein the 5-formyl-furan-2-carboxylic acid is converted into 5-hydroxymethyl-furan-2-carboxylic acid, wherein the hydrogenation catalyst is a supported metal catalyst, comprising a support and a metal supported on the support, wherein the metal is one or more of Pd and Pt, and the loading of the metal is 0.1% to 1% based on the total mass of the support; (2) Filter the reaction solution obtained in step (1), separate the catalyst, remove the solvent, and obtain solid 2,5-furandicarboxylic acid containing 5-hydroxymethyl-furan-2-carboxylic acid impurity; (3) Wash the 2,5-furandicarboxylic acid solid containing 5-hydroxymethyl-furan-2-carboxylic acid impurity obtained in step (2), dissolve the 5-hydroxymethyl-furan-2-carboxylic acid impurity in water, and the remaining solid is the purified 2,5-furandicarboxylic acid product.

2. The method according to claim 1, wherein, The 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity is derived from the primary product of the production of 2,5-furandicarboxylic acid by the oxidation of 5-hydroxymethylfurfural.

3. The method according to claim 1, wherein, The 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity contains 0.1% to 30% 5-formyl-furan-2-carboxylic acid.

4. The method according to claim 1, wherein, The 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity has a content of 0.2% to 20% of 5-formyl-furan-2-carboxylic acid.

5. The method according to claim 1, wherein, The 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity contains 0.5% to 10% 5-formyl-furan-2-carboxylic acid.

6. The method according to claim 1, wherein, In the supported metal catalyst described in step (1), the loading of the metal is 0.2% to 0.5% based on the total mass of the support.

7. The method according to claim 1, wherein, In the supported metal catalyst described in step (1), the support is one or more of activated carbon, silicon dioxide, zirconium oxide, or titanium dioxide.

8. The method according to claim 1, wherein, The mass ratio of the catalyst to the 5-formyl-furan-2-carboxylic acid impurity in step (1) is 1:0.1 to 20.

9. The method according to claim 1, wherein, The mass ratio of the catalyst to the 5-formyl-furan-2-carboxylic acid impurity in step (1) is 1:0.2 to 10.

10. The method according to claim 1, wherein, The mass ratio of the catalyst to the 5-formyl-furan-2-carboxylic acid impurity in step (1) is 1:0.5 to 5.

11. The method according to claim 1, wherein, The organic solvent mentioned in step (1) is selected from one or two of tetrahydrofuran, 1,4-dioxane or dimethyl sulfoxide.

12. The method according to claim 1, wherein, In the mixed solvent composed of organic solvent and water, the mass ratio of organic solvent to water is 5:1 to 0.5:

1.

13. The method according to claim 1, wherein, In the mixed solvent composed of organic solvent and water, the mass ratio of organic solvent to water is 3:1 to 1:

1.

14. The method according to claim 1, wherein, In the solution formed by the 2,5-furandicarboxylic acid containing the 5-formyl-furan-2-carboxylic acid impurity and the mixed solvent composed of the organic solvent and water, the mass percentage of the 2,5-furandicarboxylic acid is 0.1% to 30%.

15. The method according to claim 14, wherein, The mass percentage of the 2,5-furandicarboxylic acid is 0.5% to 20%.

16. The method of claim 14, wherein, The mass percentage of the 2,5-furandicarboxylic acid is 1-10%.

17. The method according to claim 1, wherein, The reaction temperature in step (1) is 15℃~150℃.

18. The method according to claim 1, wherein, The reaction temperature in step (1) is 40℃~140℃.

19. The method according to claim 1, wherein, The reaction temperature in step (1) is 60℃~120℃.

20. The method according to claim 1, wherein, The pressure of the hydrogen gas in step (1) is 0.1 MPa to 4 MPa.

21. The method according to claim 1, wherein, The pressure of the hydrogen gas in step (1) is 0.5 MPa to 2 MPa.

22. The method according to claim 1, wherein, The filtration temperature in step (2) is 20℃~150℃.

23. The method according to claim 1, wherein, The filtration temperature in step (2) is 50℃~120℃.