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Method used for preparing polyglycolic acid oligomer

A technology of polyglycolic acid and oligomers, which is applied in the preparation of carboxylic acid esters, chemical instruments and methods, and the preparation of organic compounds, etc., can solve the problems of low conversion rate of glycolic acid and easy evaporation, etc., to reduce evaporation, The effect of improving the conversion rate and improving the separation efficiency

Active Publication Date: 2016-02-10
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] The technical problem to be solved by the present invention is that the conversion rate of glycolic acid is relatively low when preparing polyglycolic acid oligomers in the prior art, and the problem that it is easy to evaporate in the reaction process provides a kind of low polyglycolic acid for producing glycolide The production method of the polymer is to prepare glycolic acid oligomers by melting and polycondensing glycolic acid. By controlling the heating rate and decompression rate and the structure of the distillation column, the evaporation of glycolic acid raw materials can be greatly reduced, and the glycolic acid can be improved. conversion rate of

Method used

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  • Method used for preparing polyglycolic acid oligomer
  • Method used for preparing polyglycolic acid oligomer
  • Method used for preparing polyglycolic acid oligomer

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0031] Add 400g of glycolic acid crystals and 2g of stannous octoate catalyst into the reactor, and the number of theoretical plates of the distillation column is 5. The temperature of the reaction system is raised from room temperature to 90°C. After the solid is completely dissolved, the temperature is raised to 112°C at a rate of 20°C / min to start prepolymerization. After 2 hours of prepolymerization, the temperature is raised to 200°C at a rate of 20°C / min. until no water evaporates. Then increase the vacuum to 3KPa at a decompression rate of 4KPa / min until there is no distillate, and the content of glycolic acid in the liquid collected in the receiving bottle is 14.5%.

Embodiment 2

[0033]Add 400g of glycolic acid crystals and 2g of stannous octoate catalyst into the reactor, and the number of theoretical plates of the distillation column is 5. The temperature of the reaction system is raised from room temperature to 90°C. After the solid is completely dissolved, the temperature is raised to 112°C at a rate of 15°C / min to start prepolymerization. After 2 hours of prepolymerization, the temperature is raised to 200°C at a rate of 15°C / min. until no water evaporates. Then increase the vacuum to 3KPa at a decompression rate of 2KPa / min until there is no distillate, and the content of glycolic acid in the liquid collected in the receiving bottle is 10.7%.

Embodiment 3

[0035] Add 400g of glycolic acid crystals and 2g of stannous octoate catalyst into the reactor, and the number of theoretical plates of the distillation column is 5. The temperature of the reaction system is raised from room temperature to 90°C. After the solid is completely dissolved, the temperature is raised to 112°C at a rate of 10°C / min to start prepolymerization. After 2 hours of prepolymerization, the temperature is raised to 200°C at a rate of 10°C / min. until no water evaporates. Then increase the vacuum to 3KPa at a decompression rate of 2KPa / min until there is no distillate, and the content of glycolic acid in the liquid collected in the receiving bottle is 8.9%.

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Abstract

The invention relates to a method used for preparing a polyglycolic acid oligomer. The method is used for solving problems of the prior art that glycollic acid conversion rate is low in preparation of the polyglycolic acid oligomer, and evaporating is easily caused in reaction process. The method comprises following steps: glycollic acid crystals are subjected to normal pressure condensation polymerization under normal pressure until no water is distilled anymore; decompression condensation polymerization is carried out to realize continuous condensation reaction or transesterification until no water is distilled anymore, wherein the temperature of a distillation column used in the method ranges from 80 to 110 DEG C, and theoretical plate number ranges from 5 to 30. The method is capable of solving the problems above preferably, and can be applied to industrialized production of glycolide.

Description

technical field [0001] The invention relates to a production method of glycolic acid oligomer, which is prepared by polycondensing glycolic acid. Glycolic acid oligomers are important raw materials for the preparation of glycolide, and glycolide is the most commonly used monomer for the preparation of high molecular weight polyglycolic acid. [0002] When preparing polyglycolic acid oligomers, the reaction conditions greatly affect the conversion rate of glycolic acid. By controlling the heating rate, decompression rate and the structure of the distillation column, the evaporation of glycolic acid raw materials can be greatly reduced and the glycolic acid can be improved. conversion rate. Background technique [0003] Glycolide is an important compound that can be used to prepare polyglycolic acid and its copolymers. In recent years, due to the biodegradability of polyglycolic acid and its copolymers, polyglycolic acid and polylactic acid-glycolic acid copolymers are more ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C67/08C07C69/67
Inventor 肖田鹏飞王睿周文乐朱煜
Owner CHINA PETROLEUM & CHEM CORP