CN112076790B - Zinc catalyst for controllable depolymerization by using polyester material and catalysis method thereof - Google Patents
Zinc catalyst for controllable depolymerization by using polyester material and catalysis method thereof Download PDFInfo
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- CN112076790B CN112076790B CN202010877970.5A CN202010877970A CN112076790B CN 112076790 B CN112076790 B CN 112076790B CN 202010877970 A CN202010877970 A CN 202010877970A CN 112076790 B CN112076790 B CN 112076790B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/16—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes
- B01J31/18—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes containing nitrogen, phosphorus, arsenic or antimony as complexing atoms, e.g. in pyridine ligands, or in resonance therewith, e.g. in isocyanide ligands C=N-R or as complexed central atoms
- B01J31/1805—Catalysts comprising hydrides, coordination complexes or organic compounds containing coordination complexes containing nitrogen, phosphorus, arsenic or antimony as complexing atoms, e.g. in pyridine ligands, or in resonance therewith, e.g. in isocyanide ligands C=N-R or as complexed central atoms the ligands containing nitrogen
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/03—Preparation of carboxylic acid esters by reacting an ester group with a hydroxy group
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2531/00—Additional information regarding catalytic systems classified in B01J31/00
- B01J2531/20—Complexes comprising metals of Group II (IIA or IIB) as the central metal
- B01J2531/26—Zinc
Abstract
The invention discloses a zinc catalyst for controllable depolymerization by using a polyester material and a catalytic method thereof, belonging to the technical field of polyester depolymerization. The invention solves the problems that the zinc catalyst used for alcoholysis of the existing waste polyester material needs to synthesize complex ligands and the synthesis steps are increased. The catalyst adopted by the invention is a bis (hexa-alkyl disilylazalane) zinc catalyst with a simple structure, and the polyester material can be depolymerized into small organic molecules under mild conditions through ester exchange reaction catalyzed by the catalyst in the presence of alcohol compounds, so that the waste polyester can be reused. According to the invention, the polyester is depolymerized by adopting a zinc catalyst, and the metal zinc is nontoxic, colorless, cheap and easily available, is used as one of trace elements of a human body, has good biocompatibility, and is more green and environment-friendly in production process; and the catalyst has simple structure and few synthesis steps, and the production cost is more economic. The catalyst has good universality and good depolymerization effect on polyester materials with different structures.
Description
Technical Field
The invention relates to a zinc catalyst for controllable depolymerization by using a polyester material and a catalytic method thereof, belonging to the technical field of polyester depolymerization.
Background
The polyester material has the advantages of excellent biocompatibility, biodegradability and the like, can be used as a substitute of the traditional petroleum-based polymer, is widely applied in the fields of biological medicine, packaging materials, agricultural production and the like, and gets more and more attention. However, the mass production of polyester materials also raises concerns about the post-treatment of waste polyester. Although polyester, as a degradable polymer, is capable of degrading to carbon dioxide and water, this usually requires certain harsh environmental conditions and is time consuming. The method for efficiently and conveniently realizing the post-treatment of the polyester material is an environmental problem which needs to be solved at present.
The recycling of the polymer is realized by a chemical recycling method, and an effective solution way for post-treatment of the waste polyester is provided. The chemical circulation method developed at present mainly comprises high-temperature pyrolysis, hydrolysis, enzymolysis and the like. However, pyrolysis and hydrolysis generally require the participation of high temperatures, thus increasing operating costs; the enzymolysis method has specificity, can only depolymerize certain specific polyester materials, and has certain limitation. Another chemical recycling method is to alcoholyze the polyester into small organic molecules by transesterification with alcohol. The method can realize depolymerization of the polymer and complete post-treatment of the waste polymer, and simultaneously, the generated alcoholysis product is effectively utilized as a useful chemical so as to change the waste polymer into valuables, and the method conforms to the principle of sustainable development, thereby having important research significance.
There are currently only few reports on transesterification alcoholysis of polyesters. Enthaler et al reported a method of depolymerisation of polylactide using stannous octoate catalysis (Polymer. chem., 2020, 11, 2625-2629) by microwave heating to 160 ℃ in the presence of methanol to depolymerise the polylactide to methyl lactate. However, metallic tin has some toxicity, and the high temperature condition causes the production cost to be increased. The metal zinc is nontoxic and harmless, is one of trace elements of human bodies, is biological and environment-friendly, Jones reports that a zinc complex can realize the depolymerization of polylactide, but the catalyst needs to synthesize complex ligands, the synthesis steps are increased, and the production cost is further increased (ACS Catal, 2019, 9, 409-plus 416).
Therefore, for the post-treatment of the waste polyester material, the cyclic utilization of the polymer through alcoholysis has a plurality of advantages, but a simple, efficient, green and environment-friendly catalytic system is urgently needed, so that the depolymerization of the polyester material can be rapidly realized under mild conditions. This is of great significance for environmental protection and sustainable development.
Disclosure of Invention
The invention provides a zinc catalyst for controllable depolymerization by using a polyester material and a catalytic method thereof, aiming at the problems that a complex ligand needs to be synthesized by using a zinc catalyst for alcoholysis utilization of the existing waste polyester material and the synthesis steps are increased.
Controllable depolymerization applied to polyester materialThe catalyst is bis (hexaalkyldisilazane) zinc, and the molecular formula is Zn [ N (SiR)3)2]2The structural formula is as follows:
wherein R represents an alkyl group.
Further, R is methyl.
The method for catalyzing the controllable depolymerization of the polyester material by the zinc catalyst comprises the following steps:
under the protection of inert gas at normal pressure, under the catalysis of a zinc bis (hexaalkyldisilylazalane) catalyst, polyester is dissolved in an organic solvent or other solvents are not added at a certain temperature, and depolymerization of a polyester material is carried out under the initiation of an alcohol compound to obtain organic micromolecules, so that the recycling of the polyester material is realized.
Further, the polymerization unit structure of the polyester material is as follows:
wherein R is1、R2Represents hydrogen or an alkyl or alkoxy group or an aryl or halogen atom, n is an integer of not less than 1;
the number average molecular weight of the polyester material is 102～107g/mol。
Further, the alcohol compound is an alcohol having 1 to 50 carbon atoms.
Furthermore, the alcohol compound is one or more of methanol, ethanol, isopropanol, butanol, tert-butanol, benzyl alcohol and phenylpropanol which are mixed according to any proportion.
Further, the alcohol compound is methanol.
Furthermore, the addition amount of the catalyst accounts for 0.1-10 wt% of the polyester.
Further, the reaction temperature is 20 ℃ to 200 ℃.
Further, the organic solvent is one or more of benzene, toluene, xylene, dichloromethane and tetrahydrofuran which are mixed according to any proportion.
The invention has the following beneficial effects: the catalyst adopted by the invention is a bis (hexa-alkyl disilyl nitrogen alkane) zinc catalyst with simple and green structure, and the polyester material can be depolymerized into small organic molecules under mild conditions through ester exchange reaction catalyzed by the catalyst in the presence of alcohol compounds, so that the waste polyester can be reused. The invention also has the following effects:
(1) the invention depolymerizes the polyester material into small organic molecules through the ester exchange reaction participated by the alcohol compound, thereby realizing the secondary utilization of the waste polymer and conforming to the sustainable development principle.
(2) The invention adopts the zinc catalyst with simple structure to catalyze the depolymerization of the polyester, the metal zinc is nontoxic, colorless, cheap and easily available, and is used as one of trace elements of a human body, the biocompatibility is good, and the production process is more green and environment-friendly; and the catalyst has a simple structure and few synthesis steps, so that the production cost is more economic.
(3) The invention can realize the depolymerization of the polyester under mild conditions without harsh reaction conditions such as high temperature and the like.
(4) The catalytic system adopted by the invention has good universality and good depolymerization effect on various polyester materials with different structures.
Drawings
FIG. 1 is a nuclear magnetic spectrum of the depolymerization product of polylactide in example 2.
FIG. 2 is a nuclear magnetic spectrum of the depolymerization product of poly-delta-valerolactone of example 7.
Detailed Description
The experimental procedures used in the following examples are conventional unless otherwise specified. The materials, reagents, methods and apparatus used, unless otherwise specified, are conventional in the art and are commercially available to those skilled in the art.
Example 1: depolymerization of poly beta-butyrolactone. The reaction process is as follows:
a5 mL Schlenk flask was charged with 86mg of poly β -butyrolactone (Mn 5400g/mol, PDI 1.16) in a glove box after evacuating and replacing argon, and then 3.9mg of Zn [ N (SiMe)3)2]2Catalyst, add 1mL methanol outside the glove box, stir reaction at room temperature. After 24 hours of reaction, nuclear magnetic detection is carried out on the reaction system, the conversion rate of the polymer is 93%, and the obtained alcoholysis product is 3-hydroxy methyl butyrate.
Example 2: depolymerization of polylactide. The reaction process is as follows:
a5 mL Schlenk flask was charged with 144mg of polylactide (Mn 11300g/mol, PDI 1.17) and then 7.7mg of Zn [ N (SiMe) in a glove box after evacuating and replacing the flask with argon gas3)2]2Catalyst, add 1mL methanol outside the glove box, stir reaction at room temperature. After reacting for 2h, nuclear magnetic detection is carried out on the reaction system, the conversion rate of the polymer is 99%, and the obtained alcoholysis product is methyl lactate.
Example 3: depolymerization of polylactide. The reaction process is as follows:
a5 mL Schlenk flask was charged with argon (after vacuum-baking) and charged with 11.0g of polylactide (Mn. about.49900 g/mol, PDI. about.1.13) and 550mg of Zn [ N (SiMe)3)2]2And adding 30mL of methanol outside the glove box, and stirring at normal temperature for reaction. After reacting for 40 minutes, nuclear magnetic detection is carried out on the reaction system, the conversion rate of the polymer is 99%, and the obtained alcoholysis product is methyl lactate. The remaining methanol was removed by distillation to obtain 14.2g of methyl lactate in 92% yield.
Example 4: depolymerization of polylactide. The reaction process is as follows:
after a 5mL Schlenk bottle was taken out and baked and argon gas was replaced, 144mg of polylactide (Mn 11300g/mol, PDI 1.17) was added in a glove box, dissolved in 1mL of methylene chloride solvent, and then 7.7mg of Zn [ N (SiMe) was added3)2]2Catalyst, add 1mL methanol outside the glove box, stir reaction at room temperature. After reacting for 2h, nuclear magnetic detection is carried out on the reaction system, the conversion rate of the polymer is 99%, and the obtained alcoholysis product is methyl lactate.
Example 5: depolymerization of the polyethylglycolide. The reaction process is as follows:
a5 mL Schlenk flask was charged with 86mg of polyethylglycolide (Mn 10337g/mol, PDI 1.26) and 3.9mg of Zn [ N (SiMe) in a glove box after evacuating and replacing argon gas3)2]2Catalyst, add 1mL methanol outside the glove box, stir reaction at room temperature. After reacting for 2h, nuclear magnetic detection is carried out on the reaction system, the conversion rate of the polymer is 99%, and the obtained alcoholysis product is 2-hydroxy methyl butyrate.
Example 6: depolymerization of the polybenzylglycolide. The reaction process is as follows:
a5 mL Schlenk flask was charged with 148mg of polybenzyl glycolide (Mn 9200g/mol, PDI 1.22) and 3.9mg of Zn [ N (SiMe) in a glove box after evacuating and replacing argon gas3)2]2Catalyst, add 1mL methanol outside the glove box, stir reaction at room temperature. After reacting for 2h, detecting the reaction by nuclear magnetismIn the system, the conversion rate of the polymer is 99 percent, and the obtained alcoholysis product is methyl phenyl lactate.
Example 7: depolymerization of poly delta valerolactone. The reaction process is as follows:
after a 5mL Schlenk bottle was taken out and baked and argon gas was replaced, 200mg of poly- δ -valerolactone (Mn 7400g/mol, PDI 1.22) was added to the flask, and then 7.7mg of Zn [ N (SiMe) was added thereto3)2]2Catalyst, add 1mL methanol outside the glove box, stir reaction at room temperature. After 72 hours of reaction, nuclear magnetic detection is carried out on the reaction system, the conversion rate of the polymer is 92%, and the obtained alcoholysis product is 5-hydroxy methyl valerate.
Example 8: depolymerization of poly-epsilon-caprolactone. The reaction process is as follows:
a5 mL Schlenk flask was charged with oxygen and purged with argon, and then 228mg of poly (benzylglycolide) (Mn 8300g/mol, PDI 1.16) was added to the flask, followed by 7.7mg of Zn [ N (SiMe)3)2]2The catalyst was added to the outside of the glove box in an amount of 1mL of methanol and reacted at 50 ℃ with stirring. After 72 hours of reaction, nuclear magnetic detection is carried out on the reaction system, the conversion rate of the polymer is 89%, and the obtained alcoholysis product is 6-hydroxy methyl caproate.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (8)
1. The method for catalyzing the controllable depolymerization of the polyester material by using the zinc catalyst is characterized by comprising the following steps:
under the protection of normal pressure and inert gas, polyester is dissolved in an organic solvent or is not added with other solvents under the catalysis of a zinc bis (hexaalkyldisilylazalane) catalyst at a certain temperature, and depolymerization of a polyester material is carried out under the initiation of an alcohol compound to obtain organic micromolecules, so that the recycling of the polyester material is realized;
the catalyst is bis (hexaalkyl disilylazine) zinc, and the molecular formula is Zn [ N (SiR)3)2]2The structural formula is as follows:
r is methyl.
2. The method for catalyzing the controlled depolymerization of the polyester material with the zinc catalyst according to claim 1, wherein the polymerization unit of the polyester material has a structural formula:
wherein R is1、R2Represents hydrogen or an alkyl or alkoxy group or an aryl or halogen atom, n is an integer of not less than 1;
the number average molecular weight of the polyester material is 102～107g/mol。
3. The method for catalyzing the controlled depolymerization of the polyester material with the zinc catalyst according to claim 1, wherein the alcohol compound is an alcohol containing 1-50 carbon atoms.
4. The method for catalyzing the controlled depolymerization of the polyester material with the zinc catalyst according to claim 3, wherein the alcohol compound is one or more of methanol, ethanol, isopropanol, butanol, tert-butanol, benzyl alcohol and phenylpropanol, and is formed by mixing the above components in any proportion.
5. The method of claim 4, wherein the alcohol compound is methanol.
6. The method for catalyzing the controlled depolymerization of polyester material with zinc catalyst according to claim 1, wherein the amount of said catalyst added is 0.1-10% of the polyesterwt%。
7. The method for catalyzing the controlled depolymerization of polyester material with zinc catalyst according to claim 1, wherein said reaction temperature is 20 ℃ to 200 ℃.
8. The method for catalyzing the controlled depolymerization of the polyester material with the zinc catalyst according to claim 1, wherein the organic solvent is one or more of benzene, toluene, xylene, dichloromethane and tetrahydrofuran, and the mixture is prepared by mixing the organic solvent with the toluene, the xylene, the dichloromethane and the tetrahydrofuran in any proportion.
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| PCT/CN2020/114663 WO2022041326A1 (en) | 2020-08-27 | 2020-09-11 | Zinc catalyst for catalyzing ring-opening polymerization of cyclic esters and controlled depolymerization of polyester materials and catalytic method therefor |
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| CN113150375B (en) * | 2021-03-29 | 2022-12-27 | 中国科学院青岛生物能源与过程研究所 | Method for recycling polylactic acid material under catalysis of zinc catalyst |
| CN113173856A (en) * | 2021-03-29 | 2021-07-27 | 中国科学院青岛生物能源与过程研究所 | Method for catalytic degradation of waste polyester material by using zinc catalyst |
| CN113754535A (en) * | 2021-09-08 | 2021-12-07 | 中国科学院青岛生物能源与过程研究所 | Method for catalyzing and depolymerizing polylactic acid and analogue thereof by magnesium catalysis system |
| CN113912476B (en) * | 2021-09-27 | 2023-09-26 | 中国科学院青岛生物能源与过程研究所 | Method for depolymerizing polycarbonate material by utilizing amine alcohol system |
| CN113912477B (en) * | 2021-09-27 | 2023-05-09 | 中国科学院青岛生物能源与过程研究所 | Method for catalyzing alcoholysis of polycarbonate by zinc catalyst |
| CN113912559B (en) * | 2021-09-27 | 2023-09-15 | 中国科学院青岛生物能源与过程研究所 | Method for catalyzing alcoholysis of polycarbonate amine by zinc catalyst under mild condition |
| CN113861117B (en) * | 2021-09-27 | 2023-09-12 | 中国科学院青岛生物能源与过程研究所 | Method for catalyzing ammonolysis of aromatic polycarbonate by zinc catalyst |
| CN114031600B (en) * | 2021-11-10 | 2022-12-27 | 中国科学院青岛生物能源与过程研究所 | Method for recycling caprolactone from poly epsilon-caprolactone waste |
| CN114773197A (en) * | 2022-03-11 | 2022-07-22 | 中国科学院青岛生物能源与过程研究所 | Method for recycling PET (polyethylene terephthalate) mixed plastic |
| CN114920715B (en) * | 2022-05-05 | 2023-12-19 | 中国科学院长春应用化学研究所 | Controllable depolymerization method of polycarbonate material |
| CN114797971B (en) * | 2022-05-26 | 2023-08-18 | 中国科学院青岛生物能源与过程研究所 | Organic base catalyst and method for catalyzing polycaprolactone alcoholysis by using same |
| CN116396248A (en) * | 2023-04-12 | 2023-07-07 | 大连理工大学 | Method for depolymerizing polyester into cyclic lactone |
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| DE4227299C1 (en) * | 1992-08-18 | 1994-01-27 | Hoechst Ag | Process for the preparation of monomeric terephthalic acid diesters and diols from polyesters |
| WO2001025309A1 (en) * | 1999-10-07 | 2001-04-12 | Kansai Paint Co., Ltd. | Process for producing alkyd resin |
| EP1227075B1 (en) * | 1999-10-22 | 2009-07-29 | Teijin Limited | Method for separating and recovering dimethyl terephthalate and ethylene glycol from polyester waste |
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