A method for preparing 2,5-furan dicarboxylic acid based on waste and old textiles

Abstract

The application discloses a method for preparing 2,5-furan dicarboxylic acid based on waste textiles, and relates to the field of organic polymer compounds, and comprises the following steps: S1, pretreating waste textiles to obtain cellulose powder; S2, adding the cellulose powder into a buffer system, then adding a cellulase composition, and obtaining a glucose solution after reaction; S3, mixing the glucose solution with a mixed solvent, and obtaining HMF crude product through a solid-phase catalyst in a fixed bed; and S4, mixing the HMF crude product, an oxidation catalyst composition and an acid solvent, and reacting under an oxidation gas atmosphere, and obtaining 2,5-furan dicarboxylic acid through crystallization and separation after reaction. The application uses waste textiles as raw materials, has low raw material cost and is widely available, realizes high-value utilization of waste, and meets the green and sustainable development concept. The yield and purity of 2,5-furan dicarboxylic acid are significantly higher than those of a traditional hydrobromic acid process, and the corrosion of hydrobromic acid to equipment is avoided.

Description

Technical Field

[0001] This invention relates to the field of organic polymers, specifically to a method for preparing 2,5-furandicarboxylic acid based on waste textiles and its application. Background Technology

[0002] With the depletion of fossil resources and increasingly severe environmental problems, the use of bio-based polymers to replace traditional fossil-based materials is an important direction for materials development. Currently, inorganic acids or solid sulfonic acid catalysts are commonly used to catalyze the dehydration of monosaccharides, producing 5-hydroxymethylfurfural (HMF), which is then further oxidized. However, inorganic acid catalysts are difficult to regenerate, and solid sulfonic acid catalysts are prone to reduced activity due to the formation of humin polymers on their surface. Furthermore, HMF has poor thermal stability, and traditional distillation purification processes easily form tar-like degradation products, leading to equipment downtime and reduced efficiency. In addition, traditional 2,5-furandicarboxylic acid (FDCA) oxidation processes often use hydrobromic acid, which easily causes equipment corrosion and has stringent requirements for substrate concentration, limiting production efficiency. Therefore, developing a method for preparing 2,5-furandicarboxylic acid that balances product yield, purity, and process economy in subsequent conversion steps is crucial.

[0003] Chinese invention patent application CN118164928A discloses a continuous organic-inorganic two-phase method for preparing HMF from cellulose. The method involves mixing cellulose, inorganic salts, an acidic catalyst, an organic solvent, and water, catalytically converting the mixture in a continuous reactor, and then purifying the HMF through extraction and vacuum distillation. While the raw materials in this patent are high-purity cellulose derivatives such as cellulose ethers, methylcellulose, and carboxymethylcellulose, and the composition is relatively simple and controllable, it does not demonstrate broad adaptability to raw materials or the ability to utilize waste resources. Summary of the Invention

[0004] Waste textiles, as a widely available and inexpensive natural cellulose material, are ideal bio-based raw materials. However, natural cotton fibers have high crystallinity and a dense structure, resulting in low direct conversion efficiency. Furthermore, impurities such as sizing agents and auxiliaries contained in the fibers can affect the selectivity of subsequent reactions. Current technologies lack a systematic process for the efficient conversion of waste textiles into FDCA. How to break down the dense structure of cellulose and improve reactivity through pretreatment, while simultaneously optimizing subsequent conversion steps to balance product yield, purity, and process economy, has become an urgent technical problem to be solved.

[0005] In order to break down the dense structure of cellulose and improve reactivity through pretreatment, and to develop a method for preparing 2,5-furandicarboxylic acid in which subsequent conversion steps can balance product yield, purity, and process economy, the first aspect of the present invention provides a method for preparing 2,5-furandicarboxylic acid based on waste textiles, comprising the following steps:

[0006] S1 pre-treats waste textiles to obtain cellulose powder;

[0007] S2 involves adding cellulose powder to a buffer system, then adding a cellulase composition, and after reaction and post-treatment, obtaining a glucose solution.

[0008] S3 mixes glucose solution with mixed solvent and reacts in a fixed bed with solid catalyst under pressure of 0.1-5 MPa for 1-6 h to obtain a reaction solution containing HMF. After concentration and extraction, crude HMF is obtained.

[0009] S4 involves mixing crude HMF, an oxidation catalyst, and an acid solvent, and reacting them under an oxidizing gas atmosphere at a temperature of 120-200℃ for 1-12 hours and a pressure of 0.1-5 MPa. After the reaction, 2,5-furandicarboxylic acid is obtained by crystallization.

[0010] Currently, the preparation of 2,5-furandicarboxylic acid mainly uses fructose and other monosaccharides as raw materials, which are dehydrated to produce 5-hydroxymethylfurfural and then further oxidized. Inorganic acids or solid sulfonic acid catalysts are commonly used to catalyze the dehydration of monosaccharides; however, inorganic acid catalysts are difficult to regenerate, and solid sulfonic acid catalysts are prone to reduced activity due to the formation of humin polymers on their surface. Furthermore, 5-hydroxymethylfurfural has poor thermal stability. This application uses waste textiles as raw materials. Through pretreatment, the dense structure of cellulose is broken down, impurities are removed, and crystallinity is reduced. Then, a cellulase composition is introduced to achieve enzymatic hydrolysis, forming a glucose aqueous solution, which is then catalytically converted to produce HMF and FDCA. This simplifies the process, reduces the risk of equipment corrosion, and improves production efficiency and product quality.

[0011] As one implementation method, the pretreatment of the waste textiles includes the following steps:

[0012] Waste textiles are added to water and subjected to microwave pyrolysis under an inert atmosphere to obtain pyrolysis products;

[0013] The pyrolysis products are separated by filtration, the solid phase products are eluted, and the liquid phase products are removed.

[0014] The eluted solid product was dried at 70-90℃ for 1-5 hours and then pulverized to obtain cellulose powder.

[0015] In one embodiment, the mass ratio of the waste textiles to water is 1:(0.1-3).

[0016] In one embodiment, the microwave pyrolysis treatment is carried out at a temperature of 160-250°C for 1-24 hours.

[0017] In one embodiment, the elution system is an aqueous ethanol solution, wherein the volume ratio of ethanol to water in the aqueous ethanol solution is 1:1.

[0018] In the pretreatment process, microwave treatment selectively breaks down cellulose molecular chains, removing sizing agents, auxiliaries, and low-molecular-weight impurities from waste textiles. Some amorphous regions preferentially cleave to reduce the overall crystallinity of the cellulose. Moisture acts as a microwave energy coupling medium and reaction pathway regulator, promoting the selective formation of loose, porous carbonized-semi-carbonized fiber pyrolysis products. The pyrolysis products undergo solid-liquid separation. Water or a water-alcohol system is used to elute the solid phase, removing soluble low-molecular-weight products generated during pyrolysis while retaining the structurally disrupted cellulose skeleton. The retained solid phase is then dried and mechanically pulverized to obtain a highly enzymatically hydrolyzable cellulose powder with increased specific surface area and reduced crystallinity.

[0019] In one embodiment, the buffer system is a citric acid-sodium citrate buffer system, and the pH of the buffer system is 3-6.

[0020] In one embodiment, the cellulose powder is immobilized in the buffer system at a loading of 5-20 wt%.

[0021] In one embodiment, the cellulase composition includes at least one of endoglucanase, exoglucanase, β-glucosidase, or polysaccharide-lysing monooxygenase.

[0022] In one embodiment, the amount of the cellulase composition added is 1%-5% of the mass of the cellulose powder.

[0023] In one embodiment, the cellulase composition is a combination of endoglucanase, exoglucanase, and β-glucosidase in a mass ratio of 1:(1-2):(0.1-1).

[0024] In one embodiment, the reaction temperature in step S2 is 40-60°C, and the reaction time is 5-10 hours.

[0025] In one implementation, the post-processing of step S2 is filtration, activated carbon adsorption, and secondary filtration to obtain a glucose solution.

[0026] In one embodiment, the solid-phase catalyst is a Sn-supported carboxylic acid catalyst, wherein the Sn loading is 5-20 wt%.

[0027] In one embodiment, the molar ratio of Sn in the solid catalyst to glucose in the glucose solution is (0.05-0.2):1.

[0028] In one embodiment, the temperature of the fixed bed is 150-180℃, the bed volume of the fixed bed is 100mL, and the flow rate of the mixed solvent in the fixed bed is 1-50mL / min.

[0029] In step S3, the glucose solution is mixed with a mixed solvent and reacted in a fixed-bed reactor filled with a solid catalyst. Under the action of the catalyst, the glucose is dehydrated to generate 5-hydroxymethylfurfural, resulting in a reaction solution containing HMF.

[0030] As one implementation method, the reaction solution containing HMF is concentrated and extracted to obtain crude HMF.

[0031] In one embodiment, the HMF content in the crude HMF product is 80-95 wt%.

[0032] In one embodiment, the mixed solvent is a mixture of an organic solvent and water, wherein the volume ratio of the organic solvent to water is (3-10):1.

[0033] In one embodiment, the organic solvent includes at least one of tetrahydrofuran, methyl isobutyl ketone, acetone, γ-valerolactone, and γ-butyrolactone.

[0034] In one embodiment, the molar ratio of the oxidation catalyst combination to the HMF in the crude HMF is (0.1-0.3):1.

[0035] In one embodiment, the oxidation catalyst combination includes cobalt acetate, manganese acetate, sodium bromide, and a co-catalyst, wherein the co-catalyst includes at least one of ferric nitrate, copper nitrate, or nickel nitrate.

[0036] In one embodiment, the molar ratio of cobalt acetate, manganese acetate, sodium bromide and co-catalyst is (0.1-1):(0.1-1):(0.1-1):(0.1-1).

[0037] In one embodiment, the oxygen content in the oxidizing gas atmosphere is 20-100 vol.

[0038] In one embodiment, the acid solvent includes at least one of acetic acid, propionic acid, or butyric acid.

[0039] In one embodiment, the molar ratio of the acid solvent to the HMF in the crude HMF is (4-6):1.

[0040] In one embodiment, the waste textiles include at least one of rayon, viscose filament, lyocell, cupro rayon, rayon nylon, cotton blotting, and polyester-cotton blotting.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) The method for preparing 2,5-furandicarboxylic acid based on waste textiles described in this invention uses waste textiles as raw materials. The raw materials are low in cost and widely available, realizing the high-value utilization of waste and conforming to the concept of green and sustainable development.

[0043] (2) The method for preparing 2,5-furandicarboxylic acid based on waste textiles described in this invention uses microwaves in the pretreatment to selectively break the cellulose molecular chains. Water acts as a microwave energy coupling medium and a reaction path regulator, which promotes the selective generation of loose and porous carbonized-semi-carbonized fiber structure pyrolysis products from the raw materials, thereby improving the hydrolysis efficiency of cellulose.

[0044] (3) The method for preparing 2,5-furandicarboxylic acid based on waste textiles described in this invention involves the preparation of HMF by glucose catalytic conversion, followed by concentration and extraction to obtain crude HMF with an HMF content of 80-95wt%. It can be used for subsequent oxidation reactions without complicated purification, which simplifies the production process and improves production efficiency.

[0045] (4) The method for preparing 2,5-furandicarboxylic acid based on waste textiles described in this invention further improves the efficiency of the oxidation reaction and increases the yield of 2,5-furandicarboxylic acid by introducing ferric nitrate as a co-catalyst.

[0046] (5) The method for preparing 2,5-furandicarboxylic acid based on waste textiles described in this invention is based on an oxidation catalyst combination of cobalt acetate, manganese acetate, sodium bromide and ferric nitrate, which makes the yield and purity of 2,5-furandicarboxylic acid significantly higher than that of the traditional hydrobromic acid process, and avoids the corrosion of equipment by hydrobromic acid. Detailed Implementation

[0047] Example 1

[0048] A method for preparing 2,5-furandicarboxylic acid from waste textiles includes the following steps:

[0049] S1 pre-treats waste textiles to obtain cellulose powder;

[0050] S2 involves adding cellulose powder to a buffer system, then adding a cellulase composition, and after reaction and post-treatment, obtaining a glucose solution.

[0051] S3 mixes glucose solution with mixed solvent and reacts in a fixed bed with solid catalyst at 2 MPa pressure for 3 h to obtain HMF-containing reaction solution. After concentration and extraction, crude HMF is obtained.

[0052] S4 mixes crude HMF, an oxidation catalyst, and an acid solvent, and reacts them under an oxidizing gas atmosphere at a temperature of 150°C for 6 hours and a pressure of 2 MPa. After the reaction, 2,5-furandicarboxylic acid is obtained by crystallization.

[0053] The pretreatment of the waste textiles includes the following steps:

[0054] 100g of waste textiles were added to water and subjected to microwave pyrolysis under an inert atmosphere to obtain the pyrolysis products.

[0055] The pyrolysis products are separated by filtration, the solid phase products are eluted, and the liquid phase products are removed.

[0056] The eluted solid product was dried at 80°C for 4 hours and then pulverized to obtain cellulose powder.

[0057] The waste textiles are waste clothing (100% pure cotton fabric).

[0058] The mass ratio of the waste textiles to water is 1:1.5.

[0059] The microwave pyrolysis treatment was performed at a temperature of 200°C for 12 hours.

[0060] The yield of the pyrolysis products was 65%.

[0061] The elution system is an aqueous ethanol solution, wherein the volume ratio of ethanol to water in the aqueous ethanol solution is 1:1.

[0062] The buffer system is a citric acid-sodium citrate buffer system with a pH of 5.

[0063] The cellulose powder is immobilized in the buffer system at a loading of 10 wt%.

[0064] The cellulase composition is a combination of endoglucanase, exoglucanase, and β-glucosidase in a mass ratio of 1:1:0.5.

[0065] The reaction temperature in step S2 is 50°C, and the reaction time is 8 hours.

[0066] The glucose yield was 85%, and the concentration of the glucose solution was 85 g / L.

[0067] The post-processing in step S2 involves filtration, activated carbon adsorption, and secondary filtration to obtain a glucose solution.

[0068] The solid-phase catalyst is a Sn-supported carbonized humic acid catalyst, wherein the Sn loading is 10 wt%. The Sn-supported carbonized humic acid catalyst is self-made and prepared using the method described in the

[0009] section of the published patent CN117466844A.

[0069] The molar ratio of glucose in the Sn glucose solution in the solid catalyst is 0.1:1.

[0070] The temperature of the fixed bed is 180°C, and the flow rate of the mixed solvent in the fixed bed is 25 mL / min.

[0071] The mixed solvent is an aqueous solution of tetrahydrofuran, and the volume ratio of tetrahydrofuran to water is 5:1.

[0072] The crude HMF product contains 90 wt% HMF.

[0073] The molar ratio of the oxidation catalyst combination to the HMF in the crude HMF is 0.2:1.

[0074] The oxidation catalyst composition comprises cobalt acetate, manganese acetate, sodium bromide, and a co-catalyst in a molar ratio of 0.5:0.5:0.5:0.5. The co-catalyst is ferric nitrate.

[0075] The oxygen content in the oxidizing gas atmosphere is 100 vol.

[0076] The acid solvent is acetic acid, and the molar ratio of the acid solvent to HMF in the crude HMF is 5:1.

[0077] Example 2

[0078] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the oxidizing gas atmosphere is air.

[0079] Example 3

[0080] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, except that the oxygen content in the oxidizing gas atmosphere is 40 vol.

[0081] Example 4

[0082] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the molar ratio of Sn in the solid catalyst to glucose in the glucose solution is 0.05:1.

[0083] Example 5

[0084] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the molar ratio of Sn in the solid catalyst to glucose in the glucose solution is 0.08:1.

[0085] Example 6

[0086] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the molar ratio of Sn in the solid catalyst to glucose in the glucose solution is 0.15:1.

[0087] Example 7

[0088] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the molar ratio of Sn in the solid catalyst to glucose in the glucose solution is 0.2:1.

[0089] Example 8

[0090] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the co-catalyst is copper nitrate.

[0091] Example 9

[0092] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the co-catalyst is nickel nitrate.

[0093] Example 10

[0094] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the oxidation catalyst combination includes cobalt acetate, manganese acetate and sodium bromide, with a molar ratio of 0.5:0.5:0.5.

[0095] Example 11

[0096] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the temperature of the fixed bed is 150°C.

[0097] Example 12

[0098] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, except that the temperature of the fixed bed is 160°C.

[0099] Example 13

[0100] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the temperature of the fixed bed is 170°C.

[0101] Example 14

[0102] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the acid solvent is propionic acid.

[0103] Example 15

[0104] A method for preparing 2,5-furandicarboxylic acid based on waste textiles, the specific implementation method is the same as in Example 1, the difference being that the acid solvent is butyric acid.

[0105] Comparative Example 1

[0106] A method for preparing 2,5-furandicarboxylic acid based on waste textiles is described. The specific implementation method is the same as in Example 1, except that in step S4, crude HMF is mixed with 20g of 48wt% hydrobromic acid and reacted under an oxidizing gas atmosphere at a temperature of 160℃ for 30min and a pressure of 2MPa. After the reaction, 2,5-furandicarboxylic acid is obtained by crystallization and separation.

[0107] Comparative Example 2

[0108] A method for preparing 2,5-furandicarboxylic acid based on waste textiles is described. The specific implementation method is the same as in Example 1, except that in step S4, crude HMF is mixed with 50g of 48wt% hydrobromic acid and reacted under an oxidizing gas atmosphere at a temperature of 160℃ for 30min and a pressure of 2MPa. After the reaction, 2,5-furandicarboxylic acid is obtained by crystallization and separation.

[0109] Comparative Example 3

[0110] A method for preparing 2,5-furandicarboxylic acid based on waste textiles is described. The specific implementation method is the same as in Example 1, except that in step S4, crude HMF is mixed with 80g of 48wt% hydrobromic acid and reacted under an oxidizing gas atmosphere at a temperature of 150℃ for 40min and a pressure of 2MPa. After the reaction, 2,5-furandicarboxylic acid is obtained by crystallization and separation.

[0111] Comparative Example 4

[0112] A method for preparing 2,5-furandicarboxylic acid based on waste textiles is described. The specific implementation method is the same as in Example 1, except that in step S4, crude HMF is mixed with 100g of 48wt% hydrobromic acid and reacted under an oxidizing gas atmosphere at a temperature of 150℃ for 40min and a pressure of 2MPa. After the reaction, 2,5-furandicarboxylic acid is obtained by crystallization and separation.

[0113] Performance testing

[0114] 1. FDCA purity: obtained by high performance liquid chromatography.

[0115] 2. FDCA molar yield: FDCA yield = (actual molar amount of FDCA / molar amount of HMF) × 100%

[0116] HMF molar amount = mass of crude HMF × content / 126

[0117] 3. HMF content in crude HMF: determined by high performance liquid chromatography.

[0118] The test results are shown in Table 1.

[0119] Table 1

[0120]

[0121] When using pure oxygen as the oxidant, the yield and purity of FDCA are highest in this invention. This is because pure oxygen provides a higher oxygen concentration, promoting a more complete oxidation reaction. When the molar ratio of Sn to glucose is 0.1:1, the content of crude HMF, the yield of FDCA, and its purity all reach optimal levels; ratios that are too high or too low will affect the catalytic effect. Adding a co-catalyst can significantly improve the yield and purity of FDCA, with ferric nitrate showing the best effect, followed by copper nitrate and nickel nitrate. When the fixed-bed temperature is 170℃, the content of crude HMF, the yield of FDCA, and its purity reach optimal levels; excessively high temperatures will lead to an increase in side reactions. Different acid solvents have a relatively small impact on the yield and purity of FDCA, with acetic acid showing the best effect, followed by propionic acid and butyric acid.

[0122] As can be seen from the comparison of the comparative examples and the embodiments, when using the oxidation system of the present invention, the yield and purity of FDCA are significantly higher than those of the traditional hydrobromic acid process, and the corrosion of equipment by hydrobromic acid is avoided, which fully demonstrates the superiority of the process of the present invention.

Claims

1. A method for preparing 2,5-furandicarboxylic acid based on waste textiles, characterized in that, Includes the following steps: S1 pre-treats waste textiles to obtain cellulose powder; S2 involves adding cellulose powder to a buffer system, then adding a cellulase composition, and finally processing the reaction to obtain a glucose solution. S3 mixes glucose solution with mixed solvent and reacts in a fixed bed with solid catalyst under pressure of 0.1-5 MPa for 1-6 h to obtain a reaction solution containing HMF. After concentration and extraction, crude HMF is obtained. S4 involves mixing crude HMF, an oxidation catalyst, and an acid solvent, and reacting them under an oxidizing gas atmosphere at a temperature of 120-200℃ for 1-12 hours and a pressure of 0.1-5 MPa. After the reaction, 2,5-furandicarboxylic acid is obtained by crystallization. The pretreatment of the waste textiles includes the following steps: Waste textiles are added to water and subjected to microwave pyrolysis under an inert atmosphere to obtain pyrolysis products; The pyrolysis products are separated by filtration, the solid phase products are eluted, and the liquid phase products are removed. The eluted solid product was dried at 70-90℃ for 1-5 hours and then pulverized to obtain cellulose powder. The oxidation catalyst combination comprises cobalt acetate, manganese acetate, sodium bromide, and a co-catalyst, wherein the co-catalyst is selected from at least one of ferric nitrate, copper nitrate, or nickel nitrate. The molar ratio of cobalt acetate, manganese acetate, sodium bromide and co-catalyst is (0.1-1):(0.1-1):(0.1-1):(0.1-1). The solid-phase catalyst is a Sn-supported carboxylic acid catalyst, and the Sn loading is 5-20 wt%.

2. The method for preparing 2,5-furandicarboxylic acid based on waste textiles according to claim 1, characterized in that, The molar ratio of Sn in the solid catalyst to glucose in the glucose solution is (0.05-0.2):1; the mixed solvent is a mixture of organic solvent and water, and the volume ratio of organic solvent to water is (3-10):1; the organic solvent is selected from at least one of tetrahydrofuran, methyl isobutyl ketone, acetone, γ-valerolactone, and γ-butyrolactone.

3. The method for preparing 2,5-furandicarboxylic acid based on waste textiles according to claim 1, characterized in that, The temperature of the fixed bed is 150-180℃, the bed volume of the fixed bed is 100mL, and the flow rate of the mixed solvent in the fixed bed is 1-50mL / min.

4. The method for preparing 2,5-furandicarboxylic acid based on waste textiles according to claim 1, characterized in that, The molar ratio of the oxidation catalyst combination to the HMF in the crude HMF is (0.1-0.3):

1.

5. The method for preparing 2,5-furandicarboxylic acid based on waste textiles according to claim 1, characterized in that, The oxygen content in the oxidizing gas atmosphere is 20-100 vol.

6. The method for preparing 2,5-furandicarboxylic acid based on waste textiles according to claim 1, characterized in that, The acid solvent includes at least one of acetic acid, propionic acid, or butyric acid.

7. The method for preparing 2,5-furandicarboxylic acid based on waste textiles according to claim 1, characterized in that, The waste textiles include at least one of rayon, viscose filament, lyocell, cupro rayon blend, rayon-nylon blend, cotton elastic, and polyester-cotton elastic.

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