A high-purity 2,5-furandicarboxylic acid and its preparation method

Abstract

The present invention discloses a high-purity 2,5-furandicarboxylic acid and a preparation method thereof, belonging to the technical field of chemical engineering. The method comprises the following steps: S1 Oxidation synthesis: Reacting raw materials, a catalyst and an oxidizing agent in an aqueous phase to obtain a furandicarboxylic acid reaction stock solution; wherein, the oxidizing agent is sodium hypochlorite; S2 Pretreatment: After removing the residual active chlorine-containing substances in the stock solution, a refined furandicarboxylic acid stock solution is obtained; S3 Acidification: The refined furandicarboxylic acid stock solution is adjusted in pH, and furandicarboxylic acid is precipitated by acidification. The high-purity furandicarboxylic acid product prepared by the method of the present invention has a purity of over 99.9%, and can be directly used for polymerization to prepare bio-based polyester PEF; the preparation method has the advantages of simple operation, low cost, low energy consumption and suitability for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical engineering, and particularly relates to a high-purity 2,5-furandicarboxylic acid and a preparation method thereof. Background Art

[0002] Furandicarboxylic acid (FDCA) is an important polymer monomer and can be used to synthesize a series of bio-based polyesters. Since FDCA has a similar structure to terephthalic acid (PTA), it can replace PTA and ethylene glycol to polymerize to prepare polyethylene furandicarboxylate (PEF), which is then applied to fields such as textiles, medical use, and food packaging. Currently, the common reaction processes for catalytic oxidation of 5-hydroxymethylfurfural (HMF) to prepare FDCA mainly include: noble metal + air or oxygen catalytic oxidation, CoMnBr + air or oxygen homogeneous catalysis, and nano-copper oxide + sodium hypochlorite catalytic oxidation. Among them, the nano-copper oxide + sodium hypochlorite catalytic oxidation process has the characteristics of mild reaction conditions, few by-products, and low raw material costs, and is expected to achieve low-cost and batch synthesis of FDCA. In the sodium hypochlorite reaction system, in order to ensure the full oxidation of HMF and its intermediate products, an excessive amount of sodium hypochlorite needs to be added, resulting in a small amount of active chlorine-containing substances (sodium hypochlorite, hypochlorous acid, sodium chlorate, etc.) remaining in the solution after the reaction. These active chlorine-containing substances will react with hydrochloric acid during the acidification process, generating a large number of by-products and being difficult to separate by conventional purification techniques, making the purity of FDCA fluctuate between 96% and 99%. In view of the high requirements of the polymerization process for the purity of FDCA, it is necessary to develop a method for synthesizing high-purity furandicarboxylic acid for the sodium hypochlorite oxidation process, which is of great significance for the large-scale application of FDCA. Summary of the Invention

[0003] The present invention provides a high-purity 2,5-furandicarboxylic acid and a preparation method thereof, and the main purpose is to solve the technical problem that the purity of 2,5-furandicarboxylic acid needs to be further improved.

[0004] On the one hand, the present invention provides a preparation method of high-purity 2,5-furandicarboxylic acid, and the method includes the following steps:

[0005] S1 Oxidation synthesis: Reactants, a catalyst, and an oxidant react in an aqueous phase to obtain a furandicarboxylic acid reaction stock solution; wherein, the oxidant is sodium hypochlorite;

[0006] S2 Pretreatment: After removing the residual active chlorine-containing substances in the furandicarboxylic acid reaction stock solution, a refined furandicarboxylic acid stock solution is obtained;

[0007] S3 Acidification: The refined furandicarboxylic acid stock solution is adjusted in pH, and furandicarboxylic acid is precipitated by acidification.

[0008] Optionally, the reaction raw materials include 5-hydroxymethylfurfural and / or 2,5-furandimethanol.

[0009] Optionally, the catalyst includes at least one of nano-copper oxide, nickel oxide, and cobalt oxide.

[0010] Optionally, the process of removing the residual active chlorine-containing substances in the stock solution in step S2 includes: heating the furandicarboxylic acid reaction stock solution or adding percarbonate or adding hydrogen peroxide to obtain the refined stock solution I.

[0011] Optionally, the temperature of the heating treatment is 40°C to 70°C, and the time of the heating treatment is 1 to 3 hours.

[0012] Optionally, the temperature of the heating treatment is 50°C, and the time of the heating treatment is 1 hour.

[0013] Optionally, the temperature of the heating treatment is selected from any value of 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C or the range value between any two of them.

[0014] Optionally, the time of the heating treatment is selected from any value of 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or the range value between any two of them.

[0015] Optionally, the percarbonate includes at least one of sodium percarbonate, potassium percarbonate, and calcium percarbonate.

[0016] Optionally, the ratio of the percarbonate to the furandicarboxylic acid reaction stock solution is 8 to 12 g: 1 L. That is, 8 to 12 g of percarbonate is added to each liter of the furandicarboxylic acid reaction stock solution.

[0017] Optionally, the ratio of the percarbonate to the furandicarboxylic acid reaction stock solution is 10 g: 1 L. That is, 10 g of percarbonate (10 g / L) is added to each liter of the furandicarboxylic acid reaction stock solution.

[0018] Optionally, the ratio of the percarbonate to the furandicarboxylic acid reaction stock solution is selected from any value of 8 g / L, 8.5 g / L, 9 g / L, 9.5 g / L, 10 g / L, 10.5 g / L, 11 g / L, 11.5 g / L, 12 g / L or the range value between any two of them.

[0019] Optionally, the hydrogen peroxide is a hydrogen peroxide solution, and the mass concentration of the hydrogen peroxide solution is 6% to 8%; the volume ratio of the hydrogen peroxide solution to the furandicarboxylic acid reaction stock solution is 4% to 6%.

[0020] The volume ratio of the hydrogen peroxide solution to the reaction stock solution of furandicarboxylic acid is selected from any value among 4%, 4.5%, 5%, 5.5%, 6% or the range value between any two of them.

[0021] Optionally, the mass concentration of the hydrogen peroxide solution is 7.5%.

[0022] Optionally, the volume ratio of the hydrogen peroxide solution to the reaction stock solution of furandicarboxylic acid is 5%.

[0023] Optionally, the crude purification stock solution I is adsorbed by an adsorbent material to obtain the crude purification stock solution II.

[0024] Optionally, the adsorbent material is a physical adsorbent material, and the physical adsorbent material includes activated carbon.

[0025] Optionally, the particle size of the activated carbon is less than 100 μm; the addition ratio of the activated carbon: 1 - 3 g of activated carbon is added to each liter of the crude purification stock solution I.

[0026] Optionally, the addition ratio of the activated carbon: 2 g of activated carbon is added to each liter of the crude purification stock solution I.

[0027] Optionally, concentrated hydrochloric acid is selected to adjust the pH value of the furandicarboxylic acid crude purification stock solution in the acidification of step S3; the pH value is 1.0 - 1.5.

[0028] Optionally, in step S1, the reaction raw materials, the catalyst and sodium hypochlorite react in an aqueous sodium hydroxide solution to obtain the reaction stock solution of furandicarboxylic acid;

[0029] The mass ratio of the reaction raw materials, the sodium hydroxide, the sodium hypochlorite, and the catalyst is (0.5 - 1.5):(0.5 - 1.5):(6 - 8):(0.5 - 1.5).

[0030] Optionally, the proportion of the reaction raw materials is selected from any value among 0.5, 0.8, 1.0, 1.2, 1.5 or the range value between any two of them.

[0031] The proportion of the sodium hydroxide is selected from any value among 0.5, 0.8, 1.0, 1.2, 1.5 or the range value between any two of them.

[0032] The proportion of the sodium hypochlorite is selected from any value among 6, 6.5, 7, 7.5, 8 or the range value between any two of them.

[0033] The proportion of the catalyst is selected from any value among 0.5, 0.8, 1.0, 1.2, 1.5 or the range value between any two of them.

[0034] Optionally, the mass ratio of the reaction raw material, sodium hydroxide, sodium hypochlorite, and the catalyst is 1:1:7:1.

[0035] Optionally, after the reaction of the reaction raw material, the catalyst, and the oxidant in the aqueous phase reaches a preset requirement in step S1, the catalyst is removed by filtration to obtain the crude furandicarboxylic acid reaction solution;

[0036] The refined stock solution II in step S2 is filtered to obtain the refined stock solution III.

[0037] In a second aspect, the present invention uses the above preparation method to prepare a high-purity 2,5-furandicarboxylic acid.

[0038] Optionally, the product purity of the high-purity 2,5-furandicarboxylic acid is above 99%.

[0039] Optionally, the product purity of the high-purity 2,5-furandicarboxylic acid is above 99.9%.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1) The preparation method of high-purity furandicarboxylic acid provided by this application has the characteristics of simple operation, low cost, low energy consumption, and being suitable for large-scale production.

[0042] 2) The preparation method of furandicarboxylic acid provided by this application can stably prepare a furandicarboxylic acid product with a purity as high as 99.9%, which can be directly used for polymerizing to prepare bio-based polyester PEF, and has a broad market prospect. Specific Embodiments

[0043] The following details this application with reference to embodiments, but this application is not limited to these embodiments.

[0044] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0045] In the embodiments, a 1260-type high-performance liquid chromatograph of Agilent was used to analyze the products in the oxidation synthesis of 5-hydroxymethylfurfural to furandicarboxylic acid, and the external standard method was used for quantification.

[0046] The calculation of the furandicarboxylic acid product purity is as follows:

[0047]

[0048] The embodiments of the present invention provide a specific method for synthesizing high-purity 2,5-furandicarboxylic acid, including:

[0049] S1 Synthesis stage:

[0050] 1) Weigh a certain amount of sodium hypochlorite solution (10% effective chlorine) and add it to a 100L reactor, and control the liquid temperature below 30°C using a cooling and heating integrated machine;

[0051] Among them, available chlorine means that 10g of available chlorine is contained in 100g of liquid, that is, the available chlorine content is 100g / L;

[0052] 2) Weigh a certain amount of nano copper oxide and add it into the reaction kettle, and start stirring;

[0053] 3) slowly adding a certain amount of sodium hydroxide aqueous solution and 5-hydroxymethylfurfural aqueous solution into the reactor to start the reaction;

[0054] 4) After a certain reaction time, the liquid temperature is raised to 35°C and the reaction is continued;

[0055] 5) After the selectivity of furandicarboxylic acid in the reaction solution reaches 99.9%, the reaction is stopped;

[0056] 6) After filtering and removing the catalyst, a furandicarboxylic acid reaction stock solution is obtained;

[0057] S2 preprocessing stage:

[0058] 1) Take a certain amount of reaction stock solution and add it to a beaker, then heat it to a certain temperature or add percarbonate or hydrogen peroxide, and stir for more than 2 hours;

[0059] The heating temperature used was 50°C and the heating time was 2h;

[0060] The percarbonate used is at least one of sodium percarbonate, potassium percarbonate and calcium percarbonate, and the added percarbonate mass is 10 g / L;

[0061] The hydrogen peroxide used is a hydrogen peroxide solution with a concentration of 7.5%, and the volume ratio of the hydrogen peroxide solution to the solution is 5% when added;

[0062] 2) Add a certain amount of activated carbon to the solution to adsorb impurities in the solution, and obtain a refined stock solution after filtration; the activated carbon particle size used is less than 100 μm, and the amount of activated carbon used is 2 g / L.

[0063] S3 acidification stage:

[0064] Concentrated hydrochloric acid is added to the refined stock solution to adjust the pH to 1.0-1.5, and the furandicarboxylic acid product is precipitated by acidification.

[0065] The sodium hypochlorite solution (10% effective chlorine) selected in the embodiment of the present invention means that 100g of liquid contains 10g of effective chlorine, that is, the effective chlorine content is 100g / L.

[0066] Example 1 Preparation of reaction stock solution

[0067] 80L of sodium hypochlorite solution was added to a 100L jacketed reactor, and the temperature of the solution was reduced to 10°C using a hot and cold all-in-one machine. Then, 2.5kg of sodium hydroxide was weighed and added to a beaker containing 3L of water. After dissolving and cooling, it was added to the jacketed reactor. Subsequently, 2.5kg of nano copper oxide catalyst was weighed, added to the jacketed reactor, and mechanical stirring (200rpm) was turned on. Finally, 2.5kg of 5-hydroxymethylfurfural was weighed, dissolved in 3L of water, and 5-hydroxymethylfurfural was slowly added to the jacketed reactor. After all the materials were added, the reaction was performed for 1h, and then the temperature of the solution was raised to 35°C using a hot and cold all-in-one machine to continue the reaction. When the selectivity of furandicarboxylic acid in the reaction solution reached 99.9%, the reaction was stopped and the reaction mixture was filtered to obtain the filtrate as the reaction stock solution.

[0068] Comparative Example 1 Sample 1# Preparation

[0069] 300 mL of the reaction stock solution prepared in Example 1 was added to a 500 mL three-necked flask, and 25 mL of concentrated hydrochloric acid was quickly added dropwise under stirring at a rate of about 10 mL / min. After the addition, stirring was continued for 1 h. Then, the mixed solution was filtered using 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 a furandicarboxylic acid product, named sample 1#.

[0070] Example 2 Sample 2 # preparation

[0071] 300 mL of the reaction stock solution prepared in Example 1 was added to a 500 mL three-necked flask, 1 g of sodium percarbonate was weighed and added to the flask, and stirred for 2 h. Then, 25 mL of concentrated hydrochloric acid was quickly added dropwise under stirring at a rate of about 10 mL / min, and stirring was continued for 1 h after the addition. 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 a furandicarboxylic acid product, named sample 2#.

[0072] Example 3 Sample 3 # preparation

[0073] 300 mL of the reaction stock solution prepared in Example 1 was added to a 500 mL three-necked flask, 1 g of potassium percarbonate was weighed and added to the flask, and stirred for 2 h. Then, 25 mL of concentrated hydrochloric acid was quickly added dropwise under stirring at a rate of about 10 mL / min, and stirring was continued for 1 h after the addition. 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 a furandicarboxylic acid product, named sample 3#.

[0074] Example 4 Sample 4 # preparation

[0075] Measure 300 mL of the reaction stock solution prepared in Example 1 and add it to a 500 mL three-necked flask. Weigh 1 g of calcium percarbonate and add it to the flask, then stir for 2 h. Then, quickly add 25 mL of concentrated hydrochloric acid dropwise with stirring at a dropping rate of about 10 mL / min. After dropping, continue stirring for 1 h. Subsequently, filter the mixed solution with a Buchner funnel and wash it three times with deionized water. The filter cake is dried in an oven at 55 °C for 5 h to obtain the furandicarboxylic acid product, named Sample 4#.

[0076] Example 5 Sample 5 # Preparation

[0077] Measure 300 mL of the reaction stock solution prepared in Example 1 and add it to a 500 mL three-necked flask. Place the flask in an oil bath and heat it, maintaining at 50 °C for 2 h. Then, quickly add 25 mL of concentrated hydrochloric acid dropwise with stirring at a dropping rate of about 10 mL / min. After dropping, continue stirring for 1 h. Subsequently, filter the mixed solution with a Buchner funnel and wash it three times with deionized water. The filter cake is dried in an oven at 55 °C for 5 h to obtain the furandicarboxylic acid product, named Sample 5#.

[0078] Example 6 Sample 6 # Preparation

[0079] Measure 300 mL of the reaction stock solution prepared in Example 1 and add it to a 500 mL three-necked flask. Measure 15 mL of hydrogen peroxide solution (mass concentration 7.5%) and add it to the flask, then continue stirring for 2 h. Then, quickly add 25 mL of concentrated hydrochloric acid dropwise with stirring at a dropping rate of about 10 mL / min. After dropping, continue stirring for 1 h. Subsequently, filter the mixed solution with a Buchner funnel and wash it three times with deionized water. The filter cake is dried in an oven at 55 °C for 5 h to obtain the furandicarboxylic acid product, named Sample 6#.

[0080] Example 7 Sample 7 # Preparation

[0081] Measure 300 mL of the reaction stock solution prepared in Example 1 and add it to a 500 mL three-necked flask. Weigh 1 g of sodium percarbonate and add it to the flask, then stir for 2 h. Then, weigh 0.6 g of activated carbon and add it to the flask, continue stirring for 1 h, and filter to obtain the refined stock solution. Subsequently, quickly add 25 mL of concentrated hydrochloric acid dropwise to the refined stock solution with stirring at a dropping rate of about 10 mL / min. After dropping, continue stirring for 1 h. Subsequently, filter the mixed solution with a Buchner funnel and wash it three times with deionized water. The filter cake is dried in an oven at 55 °C for 5 h to obtain the furandicarboxylic acid product, named Sample 7#.

[0082] Example 8 Sample 8 # Preparation

[0083] Measure 300 mL of the reaction stock solution prepared in Example 1 and add it to a 500 mL three-necked flask. Place the flask in an oil bath and heat it, maintaining it at 50 °C for 2 h. Then, weigh 0.6 g of activated carbon and add it to the flask. Continue stirring for 1 h and filter to obtain the refined stock solution. Subsequently, quickly add 25 mL of concentrated hydrochloric acid dropwise to the refined stock solution under stirring at a dropping rate of approximately 10 mL / min. After dropping, continue stirring for 1 h. Then, filter the mixture using a Buchner funnel and wash it three times with deionized water. Dry the filter cake in an oven at 55 °C for 5 h to obtain the furandicarboxylic acid product, named Sample 8#.

[0084] Sample 9 of Example 9 # Preparation

[0085] Measure 300 mL of the reaction stock solution prepared in Example 1 and add it to a 500 mL three-necked flask. Measure 15 mL of hydrogen peroxide solution and add it to the flask. Continue stirring for 2 h. Then, weigh 0.6 g of activated carbon and add it to the flask. Continue stirring for 1 h and filter to obtain the refined stock solution. Subsequently, quickly add 25 mL of concentrated hydrochloric acid dropwise to the refined stock solution under stirring at a dropping rate of approximately 10 mL / min. After dropping, continue stirring for 1 h. Then, filter the mixture using a Buchner funnel and wash it three times with deionized water. Dry the filter cake in an oven at 55 °C for 5 h to obtain the furandicarboxylic acid product, named Sample 9#.

[0086] Table 1. Yield and purity of FDCA prepared in Comparative Example and Examples 2-9

[0087]

[0088] HMF: 5-hydroxymethylfurfural; FDCA: furandicarboxylic acid

[0089] Table 1 shows the actual yields and purities of the furandicarboxylic acid products prepared by different methods.

[0090] In the preparation method of Comparative Example 1, the furandicarboxylic acid reaction stock solution was not pretreated, and the reaction stock solution was directly acidified; although the HMF in the stock solution had been completely converted and the selectivity of FDCA reached 99.9%, the purity of the obtained product was only 96.54%. This was because during the acidification process, the active chlorine-containing compounds would react with FDCA to form some by-products.

[0091] In the preparation methods of Examples 2-9, after pretreating the furandicarboxylic acid reaction stock solution and then acidifying it, the purity of the obtained product was increased to over 99%, and the actual FDCA yield did not decrease significantly, indicating that adding the pretreatment would not cause product loss.

[0092] In the preparation methods of Examples 7, 8, and 9, after the reaction stock solution is pretreated and combined with activated carbon adsorption, the purity of the acidified product can reach over 99.9%. Among them, when the percarbonate-activated carbon treatment method is used in Example 7, the purity of the FDCA product can reach 99.99%.

[0093] As can be seen from the above experiments, by first pretreating the reaction stock solution and then acidifying and precipitating it, the present invention can further improve the purity of the FDCA product, especially obtaining a high purity of 99.99%; the purity of 2,5-furandicarboxylic acid prepared by the method of the present invention is increased from 96.54% to 99%, 99.9% or even 99.99%, which is increased by at least three percentage points. The amplification of this technical effect in industrial production is very obvious in terms of quality improvement, and it can be directly used in the production of PEF, and the production cost is reduced.

[0094] The above are only several embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for preparing high-purity 2,5-furandicarboxylic acid, characterized in that, The method includes the following steps: S1 Oxidation synthesis: A reaction raw material, a catalyst, and an oxidant react in an aqueous sodium hydroxide solution to obtain a reaction stock solution of 2,5-furandicarboxylic acid; wherein, the oxidant is sodium hypochlorite, the reaction raw material is 5-hydroxymethylfurfural, and the catalyst is nano-copper oxide; S2 Pretreatment: After removing the residual active chlorine-containing substances in the stock solution, a refined stock solution of 2,5-furandicarboxylic acid is obtained; The process of removing the residual active chlorine-containing substances in the stock solution in step S2 includes: heating the reaction stock solution of 2,5-furandicarboxylic acid or adding percarbonate or adding hydrogen peroxide to obtain a refined stock solution of 2,5-furandicarboxylic acid; The temperature of the heating treatment is 40°C to 70°C, and the heating time is 1 to 3 hours; The percarbonate is selected from at least one of sodium percarbonate, potassium percarbonate, and calcium percarbonate; The hydrogen peroxide is a hydrogen peroxide solution, and the mass concentration of the hydrogen peroxide solution is 6% to 8%; S3 Acidification: The pH of the refined stock solution of 2,5-furandicarboxylic acid is adjusted, and 2,5-furandicarboxylic acid is precipitated by acidification.

2. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 1, characterized in that, The ratio of the percarbonate to the reaction stock solution of 2,5-furandicarboxylic acid is 8 to 12 g: 1 L.

3. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 1, characterized in that, The volume ratio of the hydrogen peroxide solution to the reaction stock solution of 2,5-furandicarboxylic acid is 4% to 6%.

4. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step S2, the refined stock solution of 2,5-furandicarboxylic acid is adsorbed by an adsorbent material to remove impurities, and a refined stock solution II is obtained; The adsorbent material is a physical adsorbent material, and the physical adsorbent material is selected from activated carbon.

5. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 4, characterized in that, The particle size of the activated carbon is less than 100 μm; the addition ratio of the activated carbon: 1 to 3 g of activated carbon is added to each liter of the refined stock solution of 2,5-furandicarboxylic acid.

6. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step S3 acidification, concentrated hydrochloric acid is selected to adjust the pH value of the refined stock solution of 2,5-furandicarboxylic acid; the pH value is 1.0 to 1.

5.

7. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 1, characterized in that, The mass ratio of the reaction raw material, the sodium hydroxide, the sodium hypochlorite, and the catalyst is (0.5 to 1.5): (0.5 to 1.5): (6 to 8): (0.5 to 1.5).

8. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 1, characterized in that, In step S1, after the reaction results of the reaction raw material, the catalyst, and the oxidant in the aqueous phase reach the preset requirements, the catalyst is filtered off to obtain the reaction stock solution of 2,5-furandicarboxylic acid.

9. The method for preparing high-purity 2,5-furandicarboxylic acid according to claim 4, characterized in that, The refined stock solution II is filtered to obtain a refined stock solution III.

Images