One-step purification method of 2,5-furandicarboxylic acid and particle preparation method

Abstract

The invention discloses a method for purifying 2,5-furandicarboxylic acid and preparing particles in one step, comprising: adding crude 2,5-furandicarboxylic acid, a certain amount of deionized water and a certain amount of activated carbon into a high-pressure reactor, stirring and reacting at high temperature for 1 hour, introducing the high-temperature solid-liquid mixture into a crystallizer through a jacket filter for cooling and crystallization (the whole mass transfer pipeline is a jacket insulation pipeline), and after the temperature in the crystallizer drops to room temperature, introducing the solid-liquid mixture into a centrifuge to obtain white crystals, and drying in an oven to obtain a high-purity product. The whole process of the invention requires a short reaction time, is extremely efficient, has a low cost, and a simple and easy-to-operate purification method, and is suitable for large-scale industrial production.

Description

Technical Field

[0001] The invention belongs to the technical field of organic chemical industry, and specifically relates to a method for purifying 2,5-furandicarboxylic acid in one step and preparing particles. Background Art

[0002] 2,5-Furandicarboxylic acid is an important chemical monomer. Its structure consists of a furan ring and two carboxyl groups. Compared with the petroleum-based monomer terephthalic acid (PTA), 2,5-Furandicarboxylic acid is mainly obtained by oxidation of various biomass platform compounds. It has a wide range of applications in food packaging, surfactants, pharmaceuticals and many other fields.

[0003] Since the chemical structure of 2,5-furandicarboxylic acid is very similar to that of PTA, 2,5-furandicarboxylic acid is currently used to replace PTA for the preparation of polyester materials and has been widely studied and applied. Since the upstream raw materials of 2,5-furandicarboxylic acid are all derived from biomass energy in nature, the development and application of 2,5-furandicarboxylic acid can help reduce global carbon emissions and alleviate environmental pollution. It is a new type of green and environmentally friendly material.

[0004] According to the survey, the annual demand for 2,5-furandicarboxylic acid in the world will exceed 1 million tons in the next ten years. Internationally, the research and industrialization of 2,5-furandicarboxylic acid started earlier in some developed countries such as Europe and the United States. In China, the research and reports on 2,5-furandicarboxylic acid have emerged in an endless stream in recent years, but the industrialization process is slow, the core technology is less mastered, and the quality of 2,5-furandicarboxylic acid is also relatively poor. Not only is the purity low, but the color is yellowish and the particle state is poor, which is far from meeting the needs of downstream polyester. The quality problems of the products need to be solved urgently. Among them, the most common are the yellowing color problem of 2,5-furandicarboxylic acid and the particle size problem of 2,5-furandicarboxylic acid monomer. The main reason is that in the process of synthesizing 2,5-furandicarboxylic acid, more monoacid impurities will be produced, such as furoic acid, 5-formylfuran-2-carboxylic acid, etc. In the synthesis process of polyester, these monoacid impurities will affect the polymerization effect, thus causing the polyester to turn yellow during the polymerization process; Regarding the particle problem of 2,5-furandicarboxylic acid in the synthesis process of polyester, the 2,5-furandicarboxylic acid monomer particles on the market are mostly powdery, and most of them float on the surface of the solvent system during the reaction, which prolongs the reaction time, and there is serious dust pollution and human harm when adding materials in large-scale production.

[0005] In the patent with publication number CN115028610A, crude 2,5-furandicarboxylic acid, a metal ion removal agent and a recrystallization solvent are mixed, and then heated under the protection of an inert gas to fully dissolve the 2,5-furandicarboxylic acid, and the filtrate is cooled, crystallized, filtered, washed and dried to obtain a preliminary refined product; under the protection of an inert gas, the preliminary refined product is dissolved in a hydrogenation solvent, and a hydrogenation reaction is carried out under the action of a solid hydrogenation catalyst and hydrogen, and then cooled, crystallized, filtered, washed and dried to obtain a pure 2,5-furandicarboxylic acid. However, this method uses a metal catalyst, and the loss of the active components of the catalyst during the hydrogenation reaction will cause the metal ion content in the 2,5-furandicarboxylic acid product to increase, affecting the purity of the product.

[0006] In the patent with publication number CN117720490A, the crude 2,5-furandicarboxylic acid is subjected to alkali dissolution, oxidation, acidification, stirring, beating, washing, and drying to obtain pure 2,5-furandicarboxylic acid. In the acidification reaction crystallization process and beating and washing process, by selecting appropriate acidification reaction temperature, oxygen content of oxidation treatment gas, beating and washing temperature, beating and washing time and other conditions, the purity of the obtained 2,5-furandicarboxylic acid can reach 99.99%, and no organic solvent is used, which can meet the requirements of polymerization-grade products. However, the numerous steps of alkali dissolution, oxidation, acidification, stirring, beating, washing, and drying in this method will increase the production cost and is not conducive to large-scale production.

[0007] In the patent with publication number CN 117820268 A, crude 2,5-furandicarboxylic acid and alkaline amine substances are subjected to acid-base neutralization reaction to obtain a mixed solution; the alkaline amine substances are selected from organic bases or ammonia water; after filtering the mixed solution and extracting and collecting the water phase, the water phase is added to the acid solution to precipitate furandicarboxylic acid under acidic conditions, and after washing and drying, pure 2,5-furandicarboxylic acid is obtained. However, the product obtained in this method has the problem of excessive ion content, which is not conducive to subsequent polymerization reactions. Summary of the invention

[0008] In view of the above problems, the purpose of the present invention is to provide a one-step purification method for 2,5-furandicarboxylic acid and particle preparation, so as to solve the problems of high impurity content, high production cost, dust safety problem and high color requirements of raw materials in downstream industries in the prior art of 2,5-furandicarboxylic acid production.

[0009] In order to solve the above problems, the present invention provides a one-step purification method of 2,5-furandicarboxylic acid and particle preparation method, comprising the following steps: S1. Place crude 2,5-furandicarboxylic acid and activated carbon in water and stir at a high temperature of 170-200°C; S2, subjecting the 2,5-furandicarboxylic acid and activated carbon slurry to high-temperature and high-pressure filter press treatment, and obtaining a 2,5-furandicarboxylic acid aqueous solution after the treatment is completed; S3, introducing the 2,5-furandicarboxylic acid aqueous solution obtained in step S2 into a crystallizer for cooling and crystallization treatment to generate a 2,5-furandicarboxylic acid slurry; S4, filtering the 2,5-furandicarboxylic acid slurry obtained in step S3 to obtain a pure wet product of 2,5-furandicarboxylic acid, and finally drying the wet product of 2,5-furandicarboxylic acid to obtain a granular pure product of 2,5-furandicarboxylic acid.

[0010] According to a further technical solution, in step S1, the mass of activated carbon added is 10-15% of the mass of crude 2,5-furandicarboxylic acid.

[0011] According to a further technical solution, in step S1, the stirring temperature is between 170°C and 200°C.

[0012] According to a further technical solution, in step S1, the crude 2,5-furandicarboxylic acid and activated carbon (10-15%) are placed in water at 170-200° C. to fully dissolve the 2,5-furandicarboxylic acid; According to a further technical solution, in step S2, the high temperature and high pressure filter press treatment specifically includes: The S1 mixed system is slurried at high temperature and then added to a high-pressure reactor. After stirring and reacting for 1-2 hours under closed pressure at 170-200°C, the high-temperature solid-liquid mixture is filtered through a jacket filter and the filtrate is introduced into a crystallizer under thermal protection.

[0013] According to a further technical solution, in step S3, the temperature is lowered to 10-25°C.

[0014] According to a further technical solution, in step S4, after the temperature in the crystallizer drops to room temperature, the solid-liquid mixture is introduced into a centrifuge to obtain white crystals, which are then dried in an oven to obtain a high-purity product.

[0015] According to a further technical solution, in step S4, the drying temperature of 2,5-furandicarboxylic acid is 70-80° C., and metal contact is avoided during drying.

[0016] In the above scheme, 2,5-furandicarboxylic acid is dissolved in water at high temperature, and the system is kept in an acidic state, which is more conducive to the adsorption of pigments and impurities by activated carbon. At the same time, after decolorization and impurity removal, granulation can be carried out purposefully by recrystallization. The overall process is simple to operate and is more suitable for large-scale production. The purity and color of the output 2,5-furandicarboxylic acid are more beneficial to the downstream polyester process.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] Compared with the existing market process, the present invention simplifies the operation, reduces the acid and alkali consumption cost, does not require special pH value control, and is more conducive to 10,000-ton scale production.

[0019] This process uses recrystallization to purposefully granulate 2,5-furandicarboxylic acid. Compared with the existing powder form, the granular form has great benefits for the production process and civil defense safety in the downstream polyester stage, and the granular 2,5-furandicarboxylic acid is more conducive to the production of downstream polyester.

[0020] Compared with the existing processes which mostly require three to four steps, this process only requires one step of purification, color removal and granulation between the high-temperature dissolving kettle and the crystallizer, which greatly saves the process and cost; In summary, the present invention avoids the residue of metal ions and other ions such as chloride ions through a one-step purification of 2,5-furandicarboxylic acid and a particle preparation method, improves product quality and color, and is more conducive to the downstream polymerization reaction. The purification method has lower cost than alkali dissolution and acid precipitation, and is suitable for large-scale chemical production.

[0021] The whole process of the present invention requires a short reaction time, is highly efficient, has a low cost, and a simple and easy-to-operate purification method, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described in conjunction with the accompanying drawings. Figure 1 This is a liquid phase chromatogram of high-purity 2,5-furandicarboxylic acid prepared in Example 3 of the present invention; Figure 2 This is the H NMR spectrum of high-purity 2,5-furandicarboxylic acid prepared in Example 3 of the present invention; Figure 3 This is a physical picture of high-purity 2,5-furandicarboxylic acid prepared in Example 3 of the present invention; Figure 4 This is a microscopic morphology of high-purity 2,5-furandicarboxylic acid particles prepared in Example 3 of the present invention; Figure 5 This is the particle size diagram of crude 2,5-furandicarboxylic acid; Figure 6 This is a particle size diagram of high-purity 2,5-furandicarboxylic acid particles prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0023] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0024] It should be noted that the activated carbon used in the embodiment is coal-based powder 240 mesh activated carbon, and the crude 2,5-furandicarboxylic acid used in the embodiment is synthesized by the inventor using HMF as raw material, sodium hypochlorite as oxidant, and non-precious metal oxide as catalyst through oxidation reaction. The specific synthesis process belongs to the prior art and will not be repeated here. The purity range of the crude 2,5-furandicarboxylic acid is: 90%~98.7%; the impurities are mainly: 5-chloro-2-furoic acid, furfural, etc.

[0025] Example 1 500 g of crude 2,5-furandicarboxylic acid (purity 98.42%, b value 2.31), 7.5 L of deionized water and 75 g of activated carbon were added to a 5 L high-pressure reactor. After stirring and reacting at 180°C for 1 hour, the high-temperature solid-liquid mixture was introduced into a crystallizer through a jacket filter for cooling and crystallization (the entire mass transfer pipeline is a jacketed insulation pipeline). After the temperature in the crystallizer dropped to 10°C, the solid-liquid mixture was introduced into a centrifuge to obtain white crystals. After drying in a 70°C oven, 479 g of solid was obtained, which was high-purity 2,5-furandicarboxylic acid crystals. The purity was 99.9% as determined by HPLC, and the b value was -0.58 as determined by a colorimeter.

[0026] Example 2

[0027] 1 kg of crude 2,5-furandicarboxylic acid (purity 98.74%, b value 2.02), 15 L of deionized water and 150 g of activated carbon were added to a 5 L high-pressure reactor. After stirring and reacting at 180°C for 1 hour, the high-temperature solid-liquid mixture was introduced into a crystallizer through a jacket filter for cooling and crystallization (the entire mass transfer pipeline is a jacketed insulation pipeline). After the temperature in the crystallizer dropped to 25°C, the solid-liquid mixture was introduced into a centrifuge to obtain white crystals. After drying in a 70°C oven, 978 g of solid was obtained, which was high-purity 2,5-furandicarboxylic acid crystals. The purity was 99.9% as determined by HPLC, and the b value was -0.47 as determined by a colorimeter.

[0028] Example 3 10 kg of crude 2,5-furandicarboxylic acid (purity 98.01%, b value 2.68), 150 L of deionized water and 1.5 kg of activated carbon were added to a 500 L high-pressure reactor. After stirring and reacting at 180°C for 1 hour, the high-temperature solid-liquid mixture was introduced into a crystallizer through a jacket filter for cooling and crystallization (the entire mass transfer pipeline is a jacketed insulation pipeline). After the temperature in the crystallizer dropped to 10°C, the solid-liquid mixture was introduced into a centrifuge to obtain white crystals. After drying in a 70°C oven, 9.75 g of solid was obtained, which was high-purity 2,5-furandicarboxylic acid crystals. The purity was 99.94% as determined by HPLC, and the b value was -0.32 as determined by a colorimeter.

[0029] Figure 1 This is a liquid phase chromatogram of high-purity 2,5-furandicarboxylic acid prepared in Example 3 of the present invention. Figure 1 It can be seen that the purity of crude 2,5-furandicarboxylic acid is increased to 99.94% through this invention; Figure 2 This is the nuclear magnetic hydrogen spectrum of high-purity 2,5-furandicarboxylic acid prepared in Example 3 of the present invention, Figure 2 It can be seen that impurities such as 5-chloro-2-furoic acid and furfural in the crude 2,5-furandicarboxylic acid of the present invention can be removed; Figure 3 This is a physical picture of high-purity 2,5-furandicarboxylic acid prepared in Example 3 of the present invention. Figure 3 It can be seen that the particle state of crude 2,5-furandicarboxylic acid is significantly improved by this invention; Figure 4 This is a microscopic morphology of high-purity 2,5-furandicarboxylic acid particles prepared in Example 3 of the present invention. Figure 4 It can be seen that the crystal form of crude 2,5-furandicarboxylic acid is significantly improved by this invention; Figure 5 The particle size diagram of crude 2,5-furandicarboxylic acid. Figure 6 The particle size diagram of high-purity 2,5-furandicarboxylic acid particles prepared in Example 3 of the present invention is shown in FIG. Figure 5 and Figure 6 By comparison, it can be seen that the particle size of the high-purity 2,5-furandicarboxylic acid particles prepared in Example 3 has changed significantly; The purification results of Examples 1-3 are shown in the following table

[0030] Through the purification process of the present invention, the purity of crude 2,5-furandicarboxylic acid is increased from 99.27% ​​before treatment to 99.9%, the b value is reduced from 2.68 before purification to -0.32, and the particle state of the crude 2,5-furandicarboxylic acid is also changed.

[0031] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A one-step purification method for 2,5-furandicarboxylic acid and particle preparation, characterized in that: The steps include: S1. Place crude 2,5-furandicarboxylic acid and activated carbon in water and stir at high temperature; S2, subjecting the 2,5-furandicarboxylic acid and activated carbon slurry to high-temperature and high-pressure filter press treatment, and obtaining a 2,5-furandicarboxylic acid aqueous solution after the treatment is completed; S3, introducing the 2,5-furandicarboxylic acid aqueous solution obtained in step S2 into a crystallizer for cooling and crystallization treatment to generate a 2,5-furandicarboxylic acid slurry; S4, filtering the 2,5-furandicarboxylic acid slurry obtained in step S3 to obtain a pure wet product of 2,5-furandicarboxylic acid, and finally drying the wet product of 2,5-furandicarboxylic acid to obtain a granular pure product of 2,5-furandicarboxylic acid.

2. The method for one-step purification of 2,5-furandicarboxylic acid and preparation of particles according to claim 1, characterized in that: In step S1, the mass of activated carbon added is 10-15% of the mass of crude 2,5-furandicarboxylic acid.

3. The method for one-step purification of 2,5-furandicarboxylic acid and preparation of particles according to claim 1, characterized in that: In step S1, the stirring temperature is between 170 and 200°C.

4. The method for one-step purification of 2,5-furandicarboxylic acid and preparation of particles according to claim 1, characterized in that: In step S2, the high temperature and high pressure filter press treatment specifically includes: The S1 mixed system is stirred at high temperature and then added into a high-pressure reactor. After stirring and reacting at 170-200°C for 1-2 hours, the high-temperature solid-liquid mixture is filtered through a jacket filter, and the filtrate is introduced into a crystallizer under thermal protection.

5. The method for one-step purification of 2,5-furandicarboxylic acid and preparation of particles according to claim 1, characterized in that: In step S3, the temperature is lowered to 10-25°C.

6. The method for one-step purification of 2,5-furandicarboxylic acid and preparation of particles according to claim 1, characterized in that: In step S4, after the temperature in the crystallizer drops to room temperature, the solid-liquid mixture is introduced into a centrifuge to obtain white crystals, which are then dried in an oven to obtain a high-purity product.

7. The method for one-step purification of 2,5-furandicarboxylic acid and preparation of particles according to claim 1, characterized in that: In step S4, the drying temperature of 2,5-furandicarboxylic acid is 70-80°C.

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