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Glycolide preparation method

A technology of glycolide and glycolic acid, which is applied in the direction of organic chemistry, can solve the problems of low purity and yield of glycolide, achieve uniform molecular weight distribution, reduce side reactions, and stabilize depolymerization

Inactive Publication Date: 2016-01-27
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] The technical problem to be solved by the present invention is that the glycolide prepared by the prior art has lower purity and yield. A kind of production method of glycolide is provided, which uses glycolic acid as raw material. Strengthen polycondensation to prepare polyglycolic acid oligomers, and then depolymerize the oligomers at high temperature to prepare glycolide

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] After adding 400g of glycolic acid crystals and 2g of stannous octoate catalyst into the reactor, the temperature was raised from room temperature to 90°C. After the solid was completely dissolved, the temperature was raised to 112°C to start prepolymerization. After 1 hour of prepolymerization, the temperature was raised to 140°C. After anhydrous distilled off, the system was kept at temperature and vacuum was started. The vacuum degree of this process is controlled at 3KPa. After the anhydrous was distilled off, the system was kept in this state and continued to react for 1 h to obtain 311 g of polyglycolic acid oligomer.

[0023] The obtained polyglycolic acid oligomer was reacted at a reaction temperature of 260° C. and a vacuum of 0.5 KPa to prepare glycolide. After 10 hours of reaction, the reaction was stopped to obtain 265 g of crude glycolide with a yield of 87%.

Embodiment 2

[0025] After adding 400g of glycolic acid crystals and 2g of stannous octoate catalyst into the reactor, the temperature was raised from room temperature to 90°C. After the solid was completely dissolved, the temperature was raised to 112°C to start prepolymerization. After 1 hour of prepolymerization, the temperature was raised to 160°C. After anhydrous distilled off, the system was kept at temperature and vacuum was started. The vacuum degree of this process is controlled at 3KPa. After the anhydrous was distilled off, the system was kept in this state and continued to react for 1 hour to obtain 308 g of polyglycolic acid oligomer.

[0026] The obtained polyglycolic acid oligomer was reacted at a reaction temperature of 260° C. and a vacuum of 0.5 KPa to prepare glycolide. After 10 hours of reaction, the reaction was stopped to obtain 268 g of crude glycolide with a yield of 88%.

Embodiment 3

[0028] After adding 400g of glycolic acid crystals and 2g of stannous octoate catalyst into the reactor, the temperature was raised from room temperature to 90°C. After the solid was completely dissolved, the temperature was raised to 112°C to start prepolymerization. After 1 hour of prepolymerization, the temperature was raised to 180°C. After anhydrous distilled off, the system was kept at temperature and vacuum was started. The vacuum degree of this process is controlled at 3KPa. After the anhydrous was distilled off, the system was kept in this state and continued to react for 1 h to obtain 300 g of polyglycolic acid oligomer.

[0029]The obtained polyglycolic acid oligomer was reacted at a reaction temperature of 260° C. and a vacuum of 0.5 KPa to prepare glycolide. After 10 hours of reaction, the reaction was stopped to obtain 265 g of crude glycolide with a yield of 87%.

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Abstract

The present invention relates to a glycolide preparation method. A purpose of the present invention is mainly to solve the problems of low purity and low yield of the prepared glycolide in the prior art. The technical scheme comprises: (1) melt condensation polymerization: a) normal pressure condensation polymerization, wherein a glycolic acid crystal is subjected to sectional reaction under a normal pressure in the presence of a condensation catalyst or a transesterification catalyst, the reaction is performed for 0.5-10 h by maintaining the reaction temperature between the glycolic acid melting point and the glycolic acid boiling point at the first stage normal pressure prepolymerization, and at the second stage normal pressure condensation polymerization, the condensation reaction or the transesterification reaction is performed at a reaction temperature of 112-220 DEG C until no water is distilled to obtain the molten glycolic acid oligomer, b) pressure reducing condensation polymerization, and c) strengthened condensation polymerization; and (2) high temperature depolymerization, wherein a depolymerization reaction is performed at a reaction temperature of 230-290 DEG C under a reaction pressure of 0.1-1 KPa so as to obtain the glycolide crude product. With the technical scheme of the present invention, the problems in the prior art are well solved, and the method can be used in the industrial glycolide production.

Description

technical field [0001] The invention relates to a production method of glycolide, which is polyglycolic acid oligomer prepared by glycolic acid polycondensation, and then depolymerized glycolic acid oligomer to prepare glycolide. Glycolide is the most important monomer for the preparation of high molecular weight polyglycolic acid. [0002] Depolymerization is an essential step in the preparation of glycolide. During depolymerization, glycolide can be obtained in high yield by controlling the depolymerization conditions. The method can quickly distill the produced glycolide, reduce side reactions, ensure a high conversion rate in the depolymerization process, and thus obtain glycolide with a high yield. Background technique [0003] Polyglycolic acid (PGA), also known as polyglycolic acid or polyglycolic acid, is the earliest commercialized synthetic surgical suture. Its synthesis mainly includes direct condensation polymerization of glycolic acid and ring-opening polymer...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12
Inventor 肖田鹏飞王睿周文乐朱煜
Owner CHINA PETROLEUM & CHEM CORP
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