Process for the preparation of polyethylene-2,5-furandicarboxylate

Abstract

The present application relates to the technical field of bio-based polyester synthesis, and particularly to a preparation method of poly(ethylene 2,5-furandicarboxylate). The method comprises the following steps: purification of 2,5-furandicarboxylic acid: sequentially using activated carbon, de-aldehyde resin and modified adsorbent to purify 2,5-furandicarboxylic acid, which can effectively reduce the content of acylfuranic acid, furfuryl acid and aldehyde impurities, reduce the occurrence of side reactions and reduce the colority of the finished product. In a reaction container, the purified 2,5-furandicarboxylic acid, ethylene glycol, a composite catalyst and a composite stabilizer are added, and after esterification and polycondensation, poly(ethylene 2,5-furandicarboxylate) is prepared; using a mixture of aluminum acetylacetonate, triphenyl antimony diacetate and zinc acetate as the catalyst of poly(ethylene 2,5-furandicarboxylate) can effectively improve the color of PEF.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bio-based polyester synthesis, in particular to a preparation method of polyethylene 2,5-furandicarboxylate. BACKGROUND

[0002] Polyethylene 2,5-furandicarboxylate (PEF) is a new type of bio-based polyester material, which has excellent gas barrier property, biocompatibility and mechanical property, and is considered as an ideal substitute for petroleum-based polyester. However, in the actual synthesis process, the PEF product prepared by using 2,5-furandicarboxylic acid (FDCA) and ethylene glycol (EG) as raw materials is often dark in color, which greatly limits its application range.

[0003] The reason is that the purity of FDCA is not enough. In the preparation process of FDCA, various impurities such as formyl furfuryl acid (FFCA), furfuryl acid (FCA) and other aldehyde impurities may be introduced. The presence of these impurities not only affects the purity of FDCA, but also triggers a series of side reactions in the subsequent esterification and polycondensation reactions, resulting in dark color of PEF product. Especially aldehyde impurities, which can easily trigger oxidation and polymerization reactions to generate colored by-products, thereby seriously affecting the color of PEF.

[0004] In addition, the selection and use of catalysts are also important reasons for the dark color of PEF. In the synthesis process of PEF, commonly used catalysts include titanium, tin and antimony, etc. However, these catalysts may trigger some side reactions such as decarboxylation and etherification during the reaction, which will generate colored by-products, resulting in deepening of PEF color. At the same time, some catalysts such as manganese and cobalt catalysts may also cause abnormal color of PEF. In addition, the toxicity problem of catalysts cannot be ignored. Some commonly used catalysts such as tin catalysts may cause harm to human body and environment, which to some extent limits the wide application of PEF.

[0005] In summary, the insufficient purity of FDCA and the improper selection and use of catalysts are the main reasons for the dark color of PEF. In order to prepare PEF products with light color and excellent performance, it is necessary to further optimize the purification process of FDCA to reduce the content of impurities; at the same time, it is also necessary to screen out catalysts with high selectivity and low toxicity, and optimize the reaction conditions to inhibit the occurrence of side reactions, improve the color and stability of PEF products. SUMMARY

[0006] In view of the shortcomings of the prior art, the purpose of the present application is to provide a preparation method of polyethylene 2,5-furandicarboxylate, which improves the problem of dark color of polyethylene 2,5-furandicarboxylate.

[0007] The preparation method of the polyethylene-2,5-furandicarboxylate comprises the following steps:

[0008] (1) Purification of 2,5-furandicarboxylic acid:

[0009] (1-1) First, add activated carbon in water and ultrasonic, then dissolve 2,5-furandicarboxylic acid, alkali and water, and then add them into the activated carbon and water after ultrasonic stirring and adsorption, and then filter to obtain a 2,5-furandicarboxylate aqueous solution;

[0010] (1-2) Heat to 60-80℃, and then sequentially pass the 2,5-furandicarboxylate aqueous solution through a chromatographic column filled with LXC-20 de-aldehyde resin and a chromatographic column filled with modified adsorbent for adsorption, so as to purify 2,5-furandicarboxylate solution, adjust the pH to 2-4 by adding acid, so that 2,5-furandicarboxylic acid is precipitated, filter and dry, and then 2,5-furandicarboxylic acid after purification is obtained.

[0011] The preparation method of the modified adsorbent is as follows: in a reaction container, 100 parts of non-polar macroporous adsorbent resin particles, 1-5 parts of methyl o-aminobenzoate, 2-8 parts of 2,3,4,5,6-pentahydroxyhexanal, 500-1000 parts of water, 2-5 parts of polyvinyl alcohol and 1-1.5 parts of benzoyl peroxide are added, and then the mixture is reacted at 85-95℃, filtered and dried to obtain the modified adsorbent.

[0012] (2) Add the purified 2,5-furandicarboxylic acid, ethylene glycol, composite catalyst and composite stabilizer in a reaction container, and then pass them through esterification reaction and polycondensation reaction to obtain polyethylene-2,5-furandicarboxylate.

[0013] The molar ratio of 2,5-furandicarboxylic acid to ethylene glycol is 1: (1.1-2.8).

[0014] The composite catalyst is a mixture of acetylacetone aluminum, triphenyl antimony diacetate and zinc acetate with a molar ratio of 1: (0.1-0.2): (0.4-0.6).

[0015] The amount of the composite catalyst is 0.05-0.1% of the mass of 2,5-furandicarboxylic acid.

[0016] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 with a mass ratio of 1: (0.2-0.4).

[0017] The amount of the composite stabilizer is 0.1-0.5% of the mass of 2,5-furandicarboxylic acid.

[0018] The reaction temperature of the esterification reaction is 160-190℃, and the reaction time is 0.5-1h.

[0019] The reaction temperature of the polycondensation reaction is 200-230 DEG C, the reaction time is 1.5-2.5 h, and the pressure is 0.05-0.098 KPa.

[0020] The molar ratio of the base to 2,5-furan dicarboxylic acid in step (1-1) is (2-3) : 1, and the mass ratio of the activated carbon to 2,5-furan dicarboxylic acid is (0.1-0.5) : 1.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] (1) The present application sequentially uses activated carbon, de-aldehyde resin and modified adsorbent to purify 2,5-furan dicarboxylic acid, which can effectively reduce the content of acylfuranic acid (FFCA), furfuryl acid (FCA) and aldehyde impurities, reduce the occurrence of side reactions and reduce the colority of the finished product.

[0023] (2) The present application modifies non-polar macroporous adsorption resin by using methyl anthranilate and 2,3,4,5,6-pentahydroxyhexanal, which greatly enhances the adsorption capacity of the non-polar macroporous adsorption resin for aldehyde impurities and improves the purity of 2,5-furan dicarboxylic acid.

[0024] (3) The present application uses a mixture of aluminum acetylacetone, triphenyl antimony diacetate and zinc acetate as a catalyst for polyethylene glycol 2,5-furan dicarboxylate, aluminum acetylacetone and zinc acetate are non-toxic catalysts, and a small amount of triphenyl antimony diacetate catalyst is added to the mixture, which can efficiently catalyze the reaction, reduce the occurrence of etherification and decarboxylation reactions and effectively improve the color of PEF.

[0025] (4) The present application uses two stabilizers with different molecular weights in combination, phosphoric acid trimethyl ester stabilizer is easy to migrate to the surface, and antioxidant 1425 can provide long-lasting protection inside, the two stabilizers synergistically inhibit the oxidation reaction in the reaction process and improve the problem of poor PEF colority. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with examples.

[0027] All raw materials used in the examples are commercially available, except for special instructions.

[0028] The LXC-20 de-aldehyde resin is purchased from Xi'an Blue Sky Science and Technology New Material Co., Ltd.

[0029] The D3520 non-polar macroporous adsorption resin is purchased from Tianjin Xijin Environmental Protection Material Technology Co., Ltd.

[0030] Example 1

[0031] The preparation method of polyethylene glycol 2,5-furan dicarboxylate comprises the following steps:

[0032] (1) Purification of 2,5-furan dicarboxylic acid:

[0033] (1-1) First, 7.8 parts by mass of activated carbon was added to 300 parts by mass of water and ultrasonicated for 0.5 h, then 78 parts by mass of 2,5-furan dicarboxylic acid, 10 parts by mass of sodium hydroxide and 300 parts by mass of water were mixed and dissolved, and then added to the activated carbon and water after ultrasonic treatment and stirred and adsorbed, and then filtered to obtain a 2,5-furan dicarboxylic acid sodium salt aqueous solution;

[0034] (1-2) The temperature was raised to 60°C, and the 2,5-furan dicarboxylic acid sodium salt aqueous solution was sequentially passed through a chromatographic column packed with LXC-20 de-aldehyde resin and a chromatographic column packed with a modified adsorbent, respectively, and the flow rate was controlled at 2 BV / h, and a 2,5-furan dicarboxylic acid sodium salt solution was obtained by purification, and hydrochloric acid was added to adjust the pH to 2, and 2,5-furan dicarboxylic acid was precipitated, filtered, and dried to obtain purified 2,5-furan dicarboxylic acid;

[0035] The preparation method of the modified adsorbent is as follows: 100 parts by mass of D3520 non-polar macroporous adsorbent resin particles, 1 part by mass of methyl o-aminobenzoate, 8 parts by mass of 2,3,4,5,6-pentahydroxyhexanal, 500 parts by mass of water, 2 parts by mass of polyvinyl alcohol, and 1 part by mass of benzoyl peroxide were added to a reaction container, and reacted at 90±5°C for 10 h, then filtered and dried to obtain the modified adsorbent;

[0036] (2) Purified 2,5-furan dicarboxylic acid, ethylene glycol, a composite catalyst, and a composite stabilizer were added to a reaction container, the temperature was raised to 160°C, and the esterification reaction was completed after 1 h of reaction, the temperature was raised to 200°C, the pressure was 0.05 KPa, and the polycondensation reaction was completed after 2.5 h of reaction to obtain 2,5-furan dicarboxylic acid ethylene glycol ester;

[0037] The molar ratio of 2,5-furan dicarboxylic acid to ethylene glycol is 1:1.1.

[0038] The composite catalyst is a mixture of acetylacetone aluminum, triphenyl antimony diacetate, and zinc acetate in a molar ratio of 1:0.1:0.4.

[0039] The amount of the composite catalyst used is 0.05% of the mass of 2,5-furan dicarboxylic acid.

[0040] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:0.2.

[0041] The amount of the composite stabilizer used is 0.1% of the mass of 2,5-furan dicarboxylic acid.

[0042] Example 2

[0043] The preparation method of the polyethylene-2,5-furandicarboxylate comprises the following steps:

[0044] (1) Purification of 2,5-furandicarboxylic acid:

[0045] (1-1) First, 26 parts by mass of activated carbon is added to 300 parts by mass of water, and ultrasonic treatment is performed for 0.5 h. Then, 52 parts by mass of 2,5-furandicarboxylic acid, 10 parts by mass of sodium hydroxide and 300 parts by mass of water are mixed and dissolved, and then added to the activated carbon and water after ultrasonic treatment for stirring and adsorption. After filtration, a 2,5-furandicarboxylic acid sodium salt aqueous solution is obtained;

[0046] (1-2) The temperature is raised to 80℃, and the 2,5-furandicarboxylic acid sodium salt aqueous solution is sequentially passed through a chromatographic column filled with LXC-20 de-aldehyde resin and a chromatographic column filled with a modified adsorbent for adsorption, with a flow rate of 2 BV / h. A 2,5-furandicarboxylic acid sodium salt solution is obtained by purification. Hydrochloric acid is added to adjust the pH to 3, and 2,5-furandicarboxylic acid is precipitated. After filtration and drying, the purified 2,5-furandicarboxylic acid is obtained.

[0047] The preparation method of the modified adsorbent is as follows: 100 parts by mass of D3520 non-polar macroporous adsorbent resin particles, 5 parts by mass of methyl anthranilate, 2 parts by mass of 2,3,4,5,6-pentahydroxyhexanal, 1000 parts by mass of water, 5 parts by mass of polyvinyl alcohol and 1.5 parts by mass of benzoyl peroxide are added to a reaction container, and reacted at 90±5℃ for 10 h. After filtration and drying, the modified adsorbent is obtained.

[0048] (2) The purified 2,5-furandicarboxylic acid, ethylene glycol, a composite catalyst and a composite stabilizer are added to a reaction container, and the temperature is raised to 190℃. The esterification reaction is completed after 0.5 h of reaction. The temperature is raised to 230℃, and the pressure is 0.098 KPa. The polycondensation reaction is completed after 1.5 h of reaction, and the polyethylene-2,5-furandicarboxylate is prepared.

[0049] The molar ratio of the 2,5-furandicarboxylic acid to the ethylene glycol is 1:2.8.

[0050] The composite catalyst is a mixture of acetylacetone aluminum, triphenyl antimony diacetate and zinc acetate in a molar ratio of 1:0.2:0.6.

[0051] The amount of the composite catalyst is 0.1% of the mass of the 2,5-furandicarboxylic acid.

[0052] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:0.4.

[0053] The amount of the composite stabilizer is 0.5% of the mass of the 2,5-furandicarboxylic acid.

[0054] Example 3

[0055] The preparation method of the polyethylene-2,5-furandicarboxylate comprises the following steps:

[0056] (1) Purification of 2,5-furandicarboxylic acid:

[0057] (1-1) First, 18 parts by mass of activated carbon is added to 300 parts by mass of water, and ultrasonic treatment is performed for 0.5 h. Then, 62 parts by mass of 2,5-furandicarboxylic acid, 10 parts by mass of sodium hydroxide and 300 parts by mass of water are mixed and dissolved, and then added to the activated carbon and water after ultrasonic treatment and stirred and adsorbed. After filtration, a 2,5-furandicarboxylic acid sodium salt aqueous solution is obtained;

[0058] (1-2) The temperature is raised to 70℃, and the 2,5-furandicarboxylic acid sodium salt aqueous solution is sequentially adsorbed through a chromatographic column filled with LXC-20 de-aldehyde resin and a chromatographic column filled with a modified adsorbent, with a flow rate of 2 BV / h. A 2,5-furandicarboxylic acid sodium salt solution is obtained by purification. Hydrochloric acid is added to adjust the pH to 4, and 2,5-furandicarboxylic acid is precipitated. After filtration and drying, the purified 2,5-furandicarboxylic acid is obtained.

[0059] The preparation method of the modified adsorbent is as follows: 100 parts by mass of D3520 non-polar macroporous adsorbent resin particles, 3 parts by mass of methyl anthranilate, 5 parts by mass of 2,3,4,5,6-pentahydroxyhexanal, 800 parts by mass of water, 3 parts by mass of polyvinyl alcohol and 1.5 parts by mass of benzoyl peroxide are added to a reaction container, and reacted at 90±5℃ for 10 h. After filtration and drying, the modified adsorbent is obtained.

[0060] (2) The purified 2,5-furandicarboxylic acid, ethylene glycol, a composite catalyst and a composite stabilizer are added to a reaction container, and the temperature is raised to 180℃. The esterification reaction is completed after 0.5 h of reaction. The temperature is raised to 210℃, and the pressure is 0.08 KPa. The polycondensation reaction is completed after 2 h of reaction, and the polyethylene-2,5-furandicarboxylate is prepared.

[0061] The molar ratio of 2,5-furandicarboxylic acid to ethylene glycol is 1:2.

[0062] The composite catalyst is a mixture of acetylacetone aluminum, triphenyl antimony diacetate and zinc acetate in a molar ratio of 1:0.15:0.5.

[0063] The amount of the composite catalyst is 0.07% of the mass of 2,5-furandicarboxylic acid.

[0064] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:0.3.

[0065] The amount of the composite stabilizer is 0.3% of the mass of 2,5-furandicarboxylic acid.

[0066] Comparative Example 1

[0067] The preparation method of the polyethylene 2,5-furan dicarboxylate comprises the following steps:

[0068] (1) Purification of 2,5-furan dicarboxylic acid: first, 18 parts by mass of activated carbon is added to 300 parts by mass of water, and then ultrasonic is performed for 0.5 h. Then, 62 parts by mass of 2,5-furan dicarboxylic acid and 10 parts by mass of sodium hydroxide are dissolved in 300 parts by mass of water, and then the mixture is added to the activated carbon and water after ultrasonic stirring and adsorption. After filtration, a 2,5-furan dicarboxylic acid sodium salt aqueous solution is obtained. Hydrochloric acid is added to adjust the pH to 4, so that 2,5-furan dicarboxylic acid is precipitated. After filtration and drying, the purified 2,5-furan dicarboxylic acid is obtained.

[0069] (2) The purified 2,5-furan dicarboxylic acid, ethylene glycol, composite catalyst and composite stabilizer are added to a reaction container, and the temperature is raised to 180°C. The esterification reaction is completed after 0.5 h of reaction. The temperature is raised to 210°C, and the pressure is 0.08 KPa. The polycondensation reaction is completed after 2 h of reaction, and the polyethylene 2,5-furan dicarboxylate is prepared.

[0070] The molar ratio of 2,5-furan dicarboxylic acid to ethylene glycol is 1:2.

[0071] The composite catalyst is a mixture of acetylacetone aluminum, triphenyl antimony diacetate and zinc acetate in a molar ratio of 1:0.15:0.5.

[0072] The amount of the composite catalyst is 0.07% of the mass of 2,5-furan dicarboxylic acid.

[0073] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:0.3.

[0074] The amount of the composite stabilizer is 0.3% of the mass of 2,5-furan dicarboxylic acid.

[0075] Comparative Example 2

[0076] The preparation method of the polyethylene 2,5-furan dicarboxylate comprises the following steps:

[0077] (1) Purification of 2,5-furan dicarboxylic acid:

[0078] (1-1) First, 18 parts by mass of activated carbon is added to 300 parts by mass of water, and then ultrasonic is performed for 0.5 h. Then, 62 parts by mass of 2,5-furan dicarboxylic acid and 10 parts by mass of sodium hydroxide are dissolved in 300 parts by mass of water, and then the mixture is added to the activated carbon and water after ultrasonic stirring and adsorption. After filtration, a 2,5-furan dicarboxylic acid sodium salt aqueous solution is obtained.

[0079] (1-2) The temperature is raised to 70℃, and the aqueous solution of sodium 2,5-furandicarboxylate is adsorbed through a chromatography column packed with LXC-20 dealdehyde resin. The flow rate is controlled at 2BV / h to purify the sodium 2,5-furandicarboxylate solution. Hydrochloric acid is added to adjust the pH to 4, so that 2,5-furandicarboxylic acid precipitates out. The solution is filtered and dried to obtain purified 2,5-furandicarboxylic acid.

[0080] (2) Add purified 2,5-furandicarboxylic acid, ethylene glycol, composite catalyst and composite stabilizer to the reaction vessel, raise the temperature to 180℃, react for 0.5h to complete the esterification reaction, raise the temperature to 210℃, pressure 0.08KPa, react for 2h to complete the polycondensation reaction, and obtain ethylene glycol 2,5-furandicarboxylic acid.

[0081] The molar ratio of 2,5-furandicarboxylic acid to ethylene glycol is 1:2.

[0082] The composite catalyst is a mixture of aluminum acetylacetonate, antimony triphenyl diacetate, and zinc acetate in a molar ratio of 1:0.15:0.5.

[0083] The amount of the composite catalyst is 0.07% of the mass of 2,5-furandicarboxylic acid.

[0084] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:0.3.

[0085] The amount of the composite stabilizer is 0.3% of the mass of 2,5-furandicarboxylic acid.

[0086] Comparative Example 3

[0087] The preparation method of the aforementioned polyethylene 2,5-furandicarboxylate includes the following steps:

[0088] (1) Purification of 2,5-furandicarboxylic acid:

[0089] (1-1) First, add 18 parts by mass of activated carbon to 300 parts by mass of water and sonicate for 0.5 h. Then, mix and dissolve 62 parts by mass of 2,5-furandicarboxylic acid and 10 parts by mass of sodium hydroxide with 300 parts by mass of water, add the mixture to the sonicated activated carbon and water, stir and adsorb, and filter to obtain an aqueous solution of sodium 2,5-furandicarboxylic acid.

[0090] (1-2) The temperature is raised to 70℃, and the aqueous solution of sodium 2,5-furandicarboxylate is adsorbed through a chromatography column packed with modified adsorbent. The flow rate is controlled at 2 BV / h to purify the sodium 2,5-furandicarboxylate solution. Hydrochloric acid is added to adjust the pH to 4, so that 2,5-furandicarboxylic acid precipitates out. The solution is filtered and dried to obtain purified 2,5-furandicarboxylic acid.

[0091] The preparation method of the modified adsorbent is as follows: 100 parts of D3520 non-polar macroporous adsorbent resin particles, 3 parts of methyl anthranilate, 5 parts of 2,3,4,5,6-pentahydroxyhexanal, 800 parts of water, 3 parts of polyvinyl alcohol, and 1.5 parts of benzoyl peroxide are added into a reaction container, and then the mixture is reacted at 90±5℃ for 10 hours; after filtration and drying, the modified adsorbent is obtained.

[0092] (2) The purified 2,5-furan dicarboxylic acid, ethylene glycol, a composite catalyst, and a composite stabilizer are added into a reaction container, and then the temperature is raised to 180℃, and the esterification reaction is completed after 0.5 hours; the temperature is raised to 210℃, and the polycondensation reaction is completed after 2 hours under a pressure of 0.08 KPa, and thus the 2,5-furan dicarboxylic acid ethylene glycol ester is prepared.

[0093] The molar ratio of the 2,5-furan dicarboxylic acid to the ethylene glycol is 1:2.

[0094] The composite catalyst is a mixture of acetylacetone aluminum, triphenyl antimony diacetate, and zinc acetate in a molar ratio of 1:0.15:0.5.

[0095] The amount of the composite catalyst is 0.07% of the mass of the 2,5-furan dicarboxylic acid.

[0096] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:0.3.

[0097] The amount of the composite stabilizer is 0.3% of the mass of the 2,5-furan dicarboxylic acid.

[0098] Comparative Example 4

[0099] The preparation method of the poly-2,5-furan dicarboxylic acid ethylene glycol ester comprises the following steps:

[0100] (1) Purification of 2,5-furan dicarboxylic acid:

[0101] (1-1) First, 18 parts of activated carbon is added into 300 parts of water, and then ultrasonic treatment is performed for 0.5 hours; then, 62 parts of 2,5-furan dicarboxylic acid and 10 parts of sodium hydroxide are dissolved in 300 parts of water, and then the mixture is added into the activated carbon and water after ultrasonic treatment, and then stirring and adsorption are performed; after filtration, the aqueous solution of 2,5-furan dicarboxylic acid sodium salt is obtained;

[0102] (1-2) The temperature is raised to 70℃, and then the aqueous solution of 2,5-furan dicarboxylic acid sodium salt is sequentially adsorbed through a chromatographic column filled with LXC-20 de-aldehyde resin and a chromatographic column filled with the modified adsorbent, and the flow rate is controlled to be 2 BV / h; the purified 2,5-furan dicarboxylic acid sodium salt solution is obtained; hydrochloric acid is added to adjust the pH to 4, so that the 2,5-furan dicarboxylic acid is precipitated; after filtration and drying, the purified 2,5-furan dicarboxylic acid is obtained.

[0103] The preparation method of the modified adsorbent is: adding 100 parts of D3520 non-polar macroporous adsorbent resin particles, 3 parts of methyl anthranilate, 5 parts of 2, 3, 4, 5, 6-pentahydroxyhexanal, 800 parts of water, 3 parts of polyvinyl alcohol, and 1.5 parts of benzoyl peroxide in a reaction container, reacting at 90±5℃ for 10h, filtering, and drying to obtain the modified adsorbent;

[0104] (2) adding purified 2,5-furan dicarboxylic acid, ethylene glycol, catalyst and composite stabilizer in the reaction container, heating to 180℃, completing esterification reaction for 0.5h, heating to 210℃, and completing polycondensation reaction for 2h under 0.08KPa pressure to prepare 2,5-furan dicarboxylic acid ethylene glycol ester;

[0105] The molar ratio of the 2,5-furan dicarboxylic acid and the ethylene glycol is 1:2.

[0106] The catalyst is triphenyl antimony diacetate.

[0107] The amount of the catalyst is 0.07% of the mass of the 2,5-furan dicarboxylic acid.

[0108] The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:0.3.

[0109] The amount of the composite stabilizer is 0.3% of the mass of the 2,5-furan dicarboxylic acid.

[0110] Comparative Example 5

[0111] The preparation method of the poly 2,5-furan dicarboxylic acid ethylene glycol ester comprises the following steps:

[0112] (1) purification of 2,5-furan dicarboxylic acid:

[0113] (1-1) first adding 18 parts of activated carbon in 300 parts of water and ultrasonic for 0.5h, then dissolving 62 parts of 2,5-furan dicarboxylic acid and 10 parts of sodium hydroxide in 300 parts of water, and then adding them into the activated carbon and water after ultrasonic and stirring and adsorbing, and then filtering to obtain a 2,5-furan dicarboxylic acid sodium salt aqueous solution;

[0114] (1-2) heating to 70℃, and then sequentially passing the 2,5-furan dicarboxylic acid sodium salt aqueous solution through a chromatography column filled with LXC-20 de-aldehyde resin and a chromatography column filled with modified adsorbent for adsorption, controlling the flow rate to be 2BV / h, and then purifying to obtain a 2,5-furan dicarboxylic acid sodium salt solution, and then adding hydrochloric acid to adjust the pH to 4, and then making 2,5-furan dicarboxylic acid precipitate, and then filtering and drying to obtain purified 2,5-furan dicarboxylic acid;

[0115] The preparation method of the modified adsorbent is: adding 100 parts of D3520 non-polar macroporous adsorbent resin particles, 3 parts of methyl anthranilate, 5 parts of 2,3,4,5,6-pentahydroxyhexanal, 800 parts of water, 3 parts of polyvinyl alcohol, and 1.5 parts of benzoyl peroxide into a reaction container, reacting at 90±5℃ for 10h, filtering, and drying to obtain the modified adsorbent;

[0116] (2) adding the purified 2,5-furan dicarboxylic acid, ethylene glycol, a composite catalyst and a stabilizer into a reaction container, heating to 180℃, and reacting for 0.5h to complete the esterification reaction, heating to 210℃, and reacting for 2h under a pressure of 0.08KPa to complete the polycondensation reaction, thereby preparing 2,5-furan dicarboxylic acid ethylene glycol ester;

[0117] The molar ratio of the 2,5-furan dicarboxylic acid and the ethylene glycol is 1:2.

[0118] The composite catalyst is a mixture of acetylacetone aluminum, triphenyl antimony diacetate and zinc acetate in a molar ratio of 1:0.15:0.5.

[0119] The amount of the composite catalyst is 0.07% of the mass of the 2,5-furan dicarboxylic acid.

[0120] The stabilizer is trimethyl phosphate.

[0121] The amount of the stabilizer is 0.3% of the mass of the 2,5-furan dicarboxylic acid.

[0122] The mass percentage content of the purified 2,5-furan dicarboxylic acid in Examples 1-3 and Comparative Examples 1-5 is detected by gas chromatography;

[0123] The 2,5-furan dicarboxylic acid ethylene glycol ester prepared in Examples 1-3 and Comparative Examples 1-5:

[0124] The intrinsic viscosity is tested by the method of GB / T14190-2017; the color is the Lab value, which is measured by a Hunter LabColorFlex EZ colorimeter according to the method of GB / T14190-2017, L: the brightness of the color, color: a, b, wherein a represents the red-green axis and b represents the yellow-blue axis.

[0125] The test results are shown in Table 1:

[0126] Table 1 Test results table

[0127]

[0128] In summary, the embodiments sequentially use activated carbon, de-aldehyde resin and modified adsorbent to purify 2,5-furan dicarboxylic acid, which can effectively reduce the content of acylfuranic acid (FFCA), furfuryl acid (FCA) and aldehyde impurities, reduce the occurrence of side reactions and reduce the colority of the finished product. Methyl anthranilate and 2,3,4,5,6-pentahydroxyhexanal are used to modify non-polar macroporous adsorbent resin, which further improves the purity of 2,5-furan dicarboxylic acid. The mixture of aluminum acetylacetonate, triphenyl antimony diacetate and zinc acetate is used as the catalyst of polyethylene glycol 2,5-furan dicarboxylate, which is more conducive to effectively improving the color of PEF. The use of two stabilizers in combination is more conducive to improving the problem of PEF color difference.

Claims

1. A method for preparing polyethylene 2,5-furandicarboxylate, characterized in that, Includes the following steps: (1) Purification of 2,5-furandicarboxylic acid: (1-1) First, add activated carbon to water and sonicate. Then, mix and dissolve 2,5-furandicarboxylic acid, alkali and water, add it to the sonicated activated carbon and water, stir and adsorb, and filter to obtain an aqueous solution of 2,5-furandicarboxylic acid. (1-2) The temperature is increased, and the aqueous solution of 2,5-furandicarboxylate is sequentially passed through a chromatography column packed with formaldehyde-removing resin LXC-20 and a chromatography column packed with modified adsorbent for adsorption. The 2,5-furandicarboxylate solution is purified. The pH is adjusted by adding acid to precipitate 2,5-furandicarboxylate. The solution is filtered and dried to obtain purified 2,5-furandicarboxylate. (2) Purified 2,5-furandicarboxylic acid, ethylene glycol, composite catalyst and composite stabilizer are added to the reaction vessel, and esterification and polycondensation are carried out to obtain ethylene glycol 2,5-furandicarboxylic acid. The modified adsorbent was prepared by modifying a nonpolar macroporous adsorption resin with methyl anthranilate and 2,3,4,5,6-pentahydroxyhexanal. The composite catalyst is a mixture of aluminum acetylacetonate, antimony triphenyl diacetate, and zinc acetate; The composite stabilizer is a mixture of trimethyl phosphate and antioxidant 1425 in a mass ratio of 1:(0.2-0.4); The molar ratio of 2,5-furandicarboxylic acid to ethylene glycol is 1:(1.1-2.8). The modified adsorbent is prepared by adding non-polar macroporous adsorption resin particles, methyl anthranilate, 2,3,4,5,6-pentahydroxyhexanal, water, polyvinyl alcohol, and benzoyl peroxide to a reaction vessel, heating the reaction vessel, filtering the mixture, and drying it to obtain the modified adsorbent. The composite catalyst is a mixture of aluminum acetylacetonate, antimony triphenyl diacetate, and zinc acetate in a molar ratio of 1:(0.1-0.2):(0.4-0.6).

2. The method for preparing polyethylene 2,5-furandicarboxylate according to claim 1, characterized in that, The amount of the composite catalyst used is 0.05-0.1% of the mass of 2,5-furandicarboxylic acid.

3. The method for preparing polyethylene 2,5-furandicarboxylate according to claim 1, characterized in that, The amount of the composite stabilizer is 0.1-0.5% of the mass of 2,5-furandicarboxylic acid.

4. The method for preparing polyethylene 2,5-furandicarboxylate according to claim 1, characterized in that, The esterification reaction is carried out at a temperature of 160-190℃ for a time of 0.5-1h.

5. The method for preparing polyethylene 2,5-furandicarboxylate according to claim 1, characterized in that, The polycondensation reaction is carried out at a temperature of 200-230℃, a reaction time of 1.5-2.5h, and a pressure of 0.05-0.098KPa.

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