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Preparation method for glycolide

A technology of glycolide and glycolic acid, applied in directions such as organic chemistry, to achieve the effect of improving yield

Inactive Publication Date: 2007-10-17
FUDAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But at present, most of the researches on the purification of lactide by recrystallization are the selection of solvents, such as patents US4727163, CN1583740, CN1757643A, etc. using ethyl acetate, JP10279577 using low-level esters, US6313319, CN1757644A and other applications of alcohols, JP6279435 using low-level alcohols, Ketones, esters or mixtures thereof, etc., although these patents disclose the recrystallization process of lactide in different solvents, but for glycolide, because it has different chemical properties and solvency from lactide, and it is more It is easy to hydrolyze or alcoholyze, and the research on its recrystallization process conditions is still worth exploring

Method used

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  • Preparation method for glycolide
  • Preparation method for glycolide
  • Preparation method for glycolide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Add 553.1 g of 99.5% glycolic acid crystals and 1.66 g of catalyst Sb to a 500 ml single-necked flask 2 o 3, put it in an oil bath, the temperature rises from room temperature to 90 ℃, after the dissolution is complete, start to slowly vacuumize, and the liquid is continuously evaporated, and the reaction is solidified at a heating rate of 5-10 ℃ / h until it turns milky white, until no liquid evaporates. The temperature was raised to 210-220°C and the reaction was continued for 4 hours. The vacuum degree was controlled at 1-3KPa during this process, and a total of 119ml of light yellow liquid was collected in the single-neck receiving flask. Then use an air condenser and a three-necked flask to receive the product, the reaction temperature gradually rises from 220 ° C to 260 ° C, and the vacuum degree is also increased to between 10-300 Pa, and the crude product of light yellow glycolide is steamed out continuously until no glycolide is present. The reaction was stop...

Embodiment 2

[0053] 470.7g of 99.5% glycolic acid crystals and 2.829g of catalyst Sb were added to a 500ml one-neck flask 2 O 3 , the experimental device and conditions after that are the same as in Example 1, and the reaction time is extended for 10h in the high-temperature melt polycondensation stage at 210-220 ° C. The subsequent experimental device and conditions are also the same as in Example 1, and the crude product of glycolide is 300.2 g, 84% yield. Put the crude glycolide product into a single-necked flask, pour 270 ml of ethyl acetate, raise the temperature and stir to dissolve, and continuously add 90 ml of acetone dropwise at the same time. When the temperature reaches 65 °C, the crystals of glycolide are completely dissolved, and it is colorless, clear and transparent. solution. Then cool down to 50-55°C to form a supersaturated solution of glycolide, drop a few drops of 0.1-1ml ether, a small amount of crystals will be precipitated on the liquid surface or in the solution,...

Embodiment 3

[0055] 333.1 g of 99.5% glycolic acid crystals and 2.0 g of catalyst Sb were added to a 500 ml one-neck flask 2 O 3 , put it in an oil bath, the temperature rises from room temperature to 90 ℃, after the dissolution is complete, start to slowly vacuumize, and the liquid is continuously evaporated, and the reaction is solidified at a heating rate of 5-10 ℃ / h until it turns milky white, until no liquid evaporates. 3.331g of stannous octoate catalyst was added to the reaction system, and then the temperature was raised to 210-220° C. to continue the reaction for 3 hours, and the vacuum degree in this process was controlled at 1-3KPa. Then use an air condenser and a three-necked flask to receive the product, the reaction temperature gradually rises from 220 ° C to 260 ° C, and the vacuum degree is also increased to between 10-300 Pa, and the crude product of light yellow glycolide is steamed out continuously until no glycolide is present. The reaction was stopped when the este...

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Abstract

The present invention belongs to the technology field for preparing cyclocompound, specific as preparation method of glycolide. The method synthesizes high purity and high productivity glycolide crystal with high-purity glycolic acid crystal as raw material through a series of steps including dewatering polycondensation, melting polycondensation, depolymerization reaction and recrystallization purifying etc. The present invention prepares glycolide through depolymerizing polyglycolic acid oligomer which is prepared by polycondensating glycolic acid in presence of coexistent two catalysts, and purify primary product of glycolide through controlling recrystallization of glycolide by dropping low boiling point solvent at appropriate temperature.The method guarantee the high conversion rate of polyglycolic acid oligomer in depolymerization procedure and stability of crystal formation of glycolide in procedure of recrystallization, and can increase productivity of glycolide.

Description

technical field [0001] The invention belongs to the technical field of preparation of cyclic compounds, and in particular relates to a preparation method of glycolide. Background technique [0002] Polyglycolic acid is an aliphatic polyester with excellent biodegradability and biocompatibility. It is widely used in internal fixation of human or animal fractures, repair of bone defects, tendon repair, and human or animal blood vessels, muscles and Suture of other tissues, etc. At present, the methods for synthesizing polyglycolic acid mainly include direct condensation polymerization and glycolide ring-opening polymerization. The reaction formula of the direct condensation polymerization method is as follows: [0003] [0004] By using glycolic acid for direct dehydration polycondensation, generally only oligomers with a relative molecular weight of tens to thousands can be obtained, which is difficult to meet the performance of the material. The ring-opening polymeriza...

Claims

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Application Information

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IPC IPC(8): C07D319/12
Inventor 杨建胡艳飞韦嘉李速明
Owner FUDAN UNIV
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