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Mixed crystal form glycolide as well as preparation method and application thereof

A technology of glycolide and mixed crystals, which is applied in the direction of organic chemistry, can solve the problems of prone to crystal transformation, cumbersome operation, and difficult control, and achieves simple and easy preparation methods, good polymerization and safety, and low solvent consumption. little effect

Pending Publication Date: 2022-03-08
WUHUAN ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN1056689A separates crude glycolide as a vapor component in the air stream from other impurities, and reclaims the cyclic ester solvent in the air stream. This method has complicated separation process and low yield
US4650851 dissolves crude glycolide in dichloromethane, then mixes it with neutral alumina and then filters it. This method is cumbersome to operate and difficult to industrialize, and the reduction of acid impurities has a lot to do with the time of mixing and stirring, so it is not easy to control
CN104619690A introduces crude glycolide and other distillates with volatile components into the rectifier, conducts rectification through gas-liquid countercurrent contact, cools and recovers glycolide, but this method needs to use high-boiling point organic solvents and solubilizers After depolymerization, the glycolide separated by the rectification device still contains a small amount of impurities and organic solvents, which needs further refining treatment
The recrystallization method is a common method for refining crude glycolide. CN100999516, CN101054371, etc. have reported the use of organic solvents such as ethyl acetate to carry out multiple recrystallization methods for crude glycolide, but the focus is basically on the recrystallization process of glycolide. The influence of ester yield, while ignoring its influence on the crystal form of glycolide
In fact, glycolide is a molecular crystal and is prone to crystal transformation

Method used

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  • Mixed crystal form glycolide as well as preparation method and application thereof
  • Mixed crystal form glycolide as well as preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] (1) Coarsely ethant is dissolved in acetate solvent at a ratio of 2 g / ml under conditions of 70 ° C, and then filtrates the impurities after the solution is filtered and the filtrate is obtained, and after the filtrate is naturally cooled to room temperature, it is directly placed directly Recrystallization in the ice water bath, which is filtered after filtration;

[0053] (2) At room temperature and 200 rpm, the pale yellow crystals obtained by step (1) were added to the isopropyl alcohol detergent at a ratio of 2 g / ml, and the solution containing white particles was added after stirring for 45min, and then Filtration, dry, to obtain white particles.

Embodiment 2

[0055] (1) The coarsely ethant is dissolved in acetone solvent at 60 ° C, and the solution is removed from the acetone solvent under the conditions of 60 ° C. Recrystallization in the water bath, which is filtered, and a light yellow crystal is filtered.

[0056] (2) At 50 ° C, 50 rpm, the pale yellow crystals prepared by step (1) were added to the n-butanol detergent at a ratio of 2.5 g / ml, and the mixture was stirred for 1 h to give a solution containing white particles. After filtration, dry, to obtain white particles.

Embodiment 3

[0058] (1) The coarsely ethant was dissolved in a n-butyl acetate solvent at 90 ° C, and the solution removal of impurities were removed after the solution was obtained, and the filtrate was obtained, and the filtrate was naturally cooled to room temperature, and then directly Recrystallization was performed in an ice water bath and a light yellow crystal was filtered.

[0059] (2) At 70 ° C, 50 rpm, the pale yellow crystals obtained by step (1) were added to the isopentyl alcohol detergent at a ratio of 2 g / ml, and the mixture was stirred for 30min to obtain a solution containing white particles, and then After filtration, dry, to obtain white particles.

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Abstract

The invention discloses mixed crystal form glycolide and a preparation method thereof, which solve the problem that the stability, polymerizability and safety of the existing glycolide need to be further improved, and the preparation method comprises the following steps: (1) dissolving crude glycolide in a solvent at 60-90 DEG C according to a proportion of 1-3 g / ml, preparing a solution, filtering to remove impurities and obtain a filtrate, after the filtrate is naturally cooled to room temperature, directly placing the filtrate in an ice-water bath for recrystallization, and filtering to obtain faint yellow lamellar crystals; and (2) under a stirring condition, adding the faint yellow lamellar crystal obtained in the step (1) into a detergent according to a ratio of 1-3 g / ml to obtain a solution containing white particles, and filtering and drying to obtain the mixed crystal form glycolide. The glycolide has a mixed crystal form and is good in stability, polymerizability and safety, the preparation method is simple, convenient and easy to implement, the cost is low, the solvent dosage is small, the purification process is short, and the solvent can be recycled.

Description

[0001] Technical solutions [0002] The present invention belongs to the field of production technology, and more particularly to a mixed crystalline type hydrazine and its preparation method and application thereof. Background technique [0003] A high molecular weight polyvyl glycolic acid is prepared. Typically, the synthesis of the glycolide is two steps: the low molecular weight polyori acid is first synthesized by esterification of glycolic acid; secondary molecular weight polyoric acid is concentrated by a high temperature solution / solvent to obtain a coarse bold alternate. However, a variety of impurities such as water, glycolic acid, low molecular weight polyoriic acid, is not conducive to the preparation of high molecular weight polyori acid. Therefore, coarsely given the need to be purified to meet the needs of polymerization. [0004] The purified method of coarse alternation has a solvent extraction method, a distillation method, and a recrystallization method, and t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12C08G63/06
CPCC07D319/12C08G63/06
Inventor 谢鸿洲王淑敏商宽祥卢文新张宗飞
Owner WUHUAN ENG