Preparation and application of biodegradable polyester based on syringic acid methyl ester derivative

Abstract

The invention discloses preparation and application of biodegradable polyester based on syringic acid methyl ester derivatives, and belongs to the technical field of high polymer materials. Methyl syringate is used as an initial raw material to react with triphosgene to obtain a novel monomer M, and then the M, spirodiol and thiadiazole are subjected to melt polymerization to obtain the biodegradable polyester. According to the preparation method provided by the invention, large-scale production of the biodegradable polyester based on methyl syringate, spirodiol and thiadiazole can be realized, the cost is relatively low, and the prepared biodegradable polyester is high in molecular weight and good in color and luster, has good mechanical properties and biodegradability, and is suitable for industrial production. The degradable plastic can be used as degradable plastic or a degradable plastic modifier to be widely applied to the fields of medical supplies, films, sustained-release materials, packaging, tableware, cosmetic bottles, fibers and textiles.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and relates to the preparation and application of a novel biodegradable polyester. Specifically, it relates to using methyl syringate as a raw material and modifying it to obtain a monomer M, and then using the monomer M, spirodiol and thiadiol as three components to prepare a biodegradable polyester by a melt polycondensation method, and the prepared biodegradable polyester is used as a degradable plastic modifier. Background Art

[0002] With the rapid growth of the global economy, polymer materials are more widely used in people's lives, and the demand for resources is also increasing. [1] ([1] Zhang Q, Song M, Xu Y, et al. Bio-based polyesters: Recent progress and future prospects [J]. Progress in Polymer Science, 2021, 120: 101430.). According to statistics, if the current fossil resource consumption rate continues, then by the end of the 21st century, the economically exploitable oil resources on the earth will be exhausted. Therefore, on the one hand, the depletion of fossil resources will have an immeasurable and serious impact on our future food, clothing, housing, transportation and other aspects; on the other hand, the large-scale consumption of fossil resources will also cause disorderly emissions of greenhouse gas CO2 and global climate and environmental problems such as greenhouse effect and white pollution caused by the extremely difficult natural degradation of petrochemical products. In view of this, the development and utilization of new resources, especially renewable biomass resources, can not only solve the current problem of resource shortage, but also reduce the impact of polymer materials on the environment, which has attracted the attention of governments around the world. [2] ([2] Tang S, Li J, Wang Z, et al. Design and Synthesis of Novel Bio-Based Polyester Elastomer with Tunable Oil Resistance[J]. Macromolecular Rapid Communications, 2023: 2300166.).

[0003] Biodegradable polymer materials are an important direction of current research on new polymer materials, and are also one of the important materials for fundamentally solving major environmental problems such as white pollution. Aliphatic polyesters have become the most important type of biodegradable polymer materials due to their highest cost-effectiveness. Currently, the aliphatic polyesters that are widely studied and can be prepared on a large scale are limited to polybutylene succinate, polylactic acid, polycaprolactone and polyhydroxy acid. However, compared with traditional plastics, these biodegradable polyesters still have key problems such as poor toughness, insufficient film tear strength or high cost, which makes it difficult to meet the material performance requirements in practical applications. It is particularly important to research and develop new low-cost degradable polyesters. Summary of the invention

[0005] In view of these problems, the technical problem to be solved by the present invention is to provide the preparation and use of biodegradable polyester based on methyl syringate derivatives. Specifically, it relates to a biodegradable polyester prepared by a melt polycondensation method using methyl syringate as a raw material and the three components of monomer M, spirodiol and thiadiacid obtained by modifying methyl syringate. The prepared biodegradable polyester is used as a degradable plastic modifier.

[0006] In order to better realize the technical solution of the present invention, the present invention discloses the preparation and use of biodegradable polyester based on methyl syringate derivatives.

[0007] The biodegradable polyester based on methyl syringate derivatives is characterized by a structure as shown in Formula 1:

[0008] In the structure of Formula 1, n is 80~100.

[0009] The method for preparing the biodegradable polyester based on methyl syringate derivatives is characterized by comprising the following four steps.

[0010] 1) Synthesis of methyl syringate derivative M: methyl syringate and triphosgene in a molar ratio of 2:1 and 0.10-0.20 times the molar amount of triethylamine of methyl syringate are added into a reaction vessel, dichloromethane is used as a reaction solvent, and the reaction is stirred at 0°C for 2 hours. After two hours, 5 drops of 1 mol / L hydrochloric acid are added to the reaction system to quench the reaction. The reaction system is washed with distilled water until neutral, and the liquids are separated. The organic phase and the inorganic phase are stored separately. The inorganic phase is extracted with dichloromethane three times to obtain the organic phase. The organic phases are combined and dried with anhydrous sodium sulfate, and then rotary evaporated to obtain the methyl syringate derivative M, whose structural formula is shown in Formula 2 .

[0011] 2) Synthesis of crude biodegradable polyester: Methyl syringate derivative M, spirodiol (CAS: 1455-42-1) and thiadiol (CAS: 30097-06-4) were added into the reactor at a molar ratio of 1.0: (2.0-2.5): 1.1, and an inert gas was introduced for protection. Under the action of a catalyst, the reaction was stirred at 185°C for 6 hours, and then vacuum was introduced and the temperature was raised to 240°C at a rate of 2°C / min. The reaction was continued for 2.5 hours, and the reaction was stopped to obtain a crude copolyester.

[0012] 3) Purification of crude biodegradable polyester: After the crude copolyester obtained under the protection of inert gas is cooled, an appropriate amount of chloroform is added, and it is soaked for 5 hours and then centrifuged. The supernatant is filtered and added dropwise to methanol to precipitate a solid, which is filtered to obtain a white solid. The white solid is washed with methanol 3 times and then vacuum dried at 60°C~70°C for 2~3 hours to obtain a purified biodegradable polyester P based on methyl syringate derivative.

[0013] As a further preference: the catalyst in step 2) is one of tetra-n-butylgermanium, dicarboxyethylgermanium trioxide, monobutyltin oxide, and di-n-butyltin dilaurate, and the amount used is 0.10% to 0.45% of the total mass of methyl syringate derivative M, spirodiol, and thiadiacid.

[0014] As further preferred, the inert gas in steps 1), 2) and 3) is one of nitrogen, helium, neon and argon.

[0015] The present invention also provides the use of monomer M, spirodiol and thiadiol degradable plastic modifier obtained by modifying methyl syringate as a raw material as described in the above technical solution. The preparation method provided by the present invention can realize the large-scale production of biodegradable polyesters of monomer M, spirodiol and thiadiol obtained by modifying methyl syringate as a raw material, with low cost, and the prepared biodegradable polyester has high molecular weight, good color, good mechanical properties and biodegradability, and can be widely used in the fields of medical supplies, films, sustained-release materials, packaging, tableware, cosmetic bottles, fibers and textiles as degradable plastics or degradable plastic modifiers.

[0016] Specific implementation plan

[0017] In order to further illustrate the present invention, the present invention is further described below in conjunction with some specific examples, but the present invention is not limited by the examples. The raw materials required for the present invention are all drugs commonly sold on the market.

[0018] Example 1.

[0019] Synthesis of monomer M of methyl syringate derivative: 4.23g (0.02mol) methyl syringate, 2.98g (0.01mol) triphosgene and 0.35g triethylamine were put into a reaction container, dichloromethane was used as the reaction solvent, and the reaction was stirred at 0°C for 2h. Two hours later, 5 drops of 1mol / L hydrochloric acid were added to the reaction system to quench the reaction. The reaction system was washed with distilled water until neutral, and the liquids were separated. The organic phase and the inorganic phase were stored separately. The inorganic phase was extracted with dichloromethane three times to obtain the organic phase. The organic phase was combined and dried with anhydrous sodium sulfate, and the methyl syringate derivative M was obtained by rotary evaporation, namely: 3.61g, yield: 80.22%.

[0020] Example 2.

[0021] Into the dried single-necked flask, 4.401 g (0.01 mol) of methyl syringate derivative M, 6.085 g (0.02 mol) of spiroglycol, 1.77 g (0.01 mol) of thiadipic acid and 0.013 g of di-n-butyltin dilaurate were added in sequence, and under nitrogen environment, good stirring was maintained. After reacting at 185°C for 6 hours, vacuum was introduced and the temperature was increased to 240°C at a heating rate of 2.0°C / min, and the reaction was continued for 2.5 hours before stopping the reaction to obtain a crude copolyester. After the crude copolyester was cooled under nitrogen protection, 50 ml of chloroform was added, and the mixture was soaked for 5 hours and then centrifuged. After centrifugation, the supernatant was added dropwise into a sufficient amount of methanol to precipitate a solid, which was filtered to obtain a white solid. The white solid was washed with methanol three times and then vacuum dried at 60°C for 2 hours to obtain 9.895 g of a pure copolyester P1 based on methyl syringate, with a number average molecular weight of 42550 g / mol and a yield of 80.73%.

[0022] Example 3.

[0023] Into the dried single-necked flask, 4.401 g (0.01 mol) of methyl syringate derivative M, 6.688 g (0.022 mol) of spiroglycol, 1.95 g (0.011 mol) of thiadipic acid and 0.015 g of tetra-n-butylgermanium were added in sequence, and under nitrogen environment, good stirring was maintained. After reacting at 190°C for 6 hours, vacuum was introduced and the temperature was increased to 250°C at a heating rate of 2.0°C / min, and the reaction was continued for 2.5 hours before stopping the reaction to obtain a crude copolyester. After the crude copolyester was cooled under nitrogen protection, 50 ml of chloroform was added, and the mixture was soaked for 5 hours and then centrifuged. After centrifugation, the supernatant was added dropwise into a sufficient amount of methanol to precipitate a solid, which was filtered to obtain a white solid. The white solid was washed with methanol three times and then vacuum dried at 60°C for 2 hours to obtain 9.703 g of a pure copolyester P2 based on methyl syringate, with a number average molecular weight of 43250 g / mol and a yield of 80.83%.

[0024] Example 4.

[0025] Into the dried single-necked flask, 4.401 g (0.01 mol) of methyl syringate derivative M, 6.992 g (0.023 mol) of spirodiol, 1.95 g (0.011 mol) of thiadipic acid and 0.016 g of dicarboxyethyl germanium trioxide were added in sequence, and under nitrogen environment, good stirring was maintained. After reacting at 185°C for 6 hours, vacuum was introduced and the temperature was increased to 245°C at a heating rate of 2.0°C / min, and the reaction was continued for 2 hours before stopping the reaction to obtain a crude copolyester. After the crude copolyester was cooled under nitrogen protection, 50 ml of chloroform was added, and the mixture was soaked for 5 hours and then centrifuged. After centrifugation, the supernatant was added dropwise into a sufficient amount of methanol to precipitate a solid, which was filtered to obtain a white solid. The white solid was washed with methanol three times and then vacuum dried at 60°C for 2 hours to obtain 9.786 g of a pure copolyester P3 based on methyl syringate, with a number average molecular weight of 43850 g / mol and a yield of 81.25%.

[0026] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. Biodegradable polyester based on methyl syringate derivatives, characterized in that The structural formula is shown in Formula 1: In the structure of Formula 1, n is 50~85.

2. The method for preparing a biodegradable polyester based on methyl syringate derivatives according to claim 1, characterized in that It includes the following four steps: 1) Synthesis of methyl syringate derivative M: methyl syringate and triphosgene in a molar ratio of 2:1 and 0.10-0.20 times the molar amount of triethylamine of methyl syringate are added into a reaction vessel, dichloromethane is used as a reaction solvent, and the reaction is stirred at 0°C for 2 hours. After two hours, 5 drops of 1 mol / L hydrochloric acid are added to the reaction system to quench the reaction. The reaction system is washed with distilled water until neutral, and the liquids are separated. The organic phase and the inorganic phase are stored separately. The inorganic phase is extracted with dichloromethane three times to obtain the organic phase. The organic phases are combined and dried with anhydrous sodium sulfate, and the methyl syringate derivative M is obtained by rotary evaporation. Its structural formula is shown in Formula 2: 2) Synthesis of crude biodegradable polyester: methyl syringate derivative M, spirodiol (CAS: 1455-42-1) and thiadiol (CAS: 30097-06-4) were added into a reactor at a molar ratio of 1.0: (2.0-2.5): 1.1, and inert gas was introduced for protection. Under the action of a catalyst, the reaction was stirred at 185°C for 6 hours, and then vacuum was introduced and the temperature was raised to 240°C at a rate of 2°C / min. The reaction was continued for 2.5 hours, and the reaction was stopped to obtain a crude copolyester. 3) Purification of crude biodegradable polyester: After the crude copolyester obtained under inert gas protection was cooled, an appropriate amount of chloroform was added, and the mixture was soaked for 5 hours and then centrifuged. The supernatant was filtered and added dropwise into methanol to precipitate a solid. A white solid was obtained by filtration. The white solid was washed with methanol for 3 times and then the obtained solid was vacuum dried at 60°C-70°C for 2-3 hours to obtain a purified biodegradable polyester P based on methyl syringate derivative.

3. The method for preparing a biodegradable polyester based on methyl syringate derivatives according to claim 2, characterized in that The catalyst in step 2) is one of tetra-n-butylgermanium, dicarboxyethyl germanium trioxide, monobutyltin oxide, and di-n-butyltin dilaurate, and the amount used is 0.10% to 0.45% of the total mass of methyl syringate derivative M, spirodiol, and thiadiacid.

4. The method for preparing a biodegradable polyester based on methyl syringate derivatives according to claim 2, characterized in that The inert gas in steps 1), 2) and 3) is one of nitrogen, helium, neon and argon.

5. Use of the biodegradable polyester based on methyl syringate derivatives as claimed in claim 2 as a degradable plastic modifier.

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