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Method for preparing high-purity glycolide

A glycolide, high-purity technology, applied in the field of preparing high-purity glycolide, can solve the problems of high cost of glycolide synthesis, inconvenience for industrialization, and high energy consumption

Active Publication Date: 2021-09-03
SHANGHAI DONGGENG CHEM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a method for preparing high-purity glycolide, which is used to solve the problem of high synthetic cost, low production efficiency, and high energy consumption of glycolide in the prior art. , large amount of three wastes, not convenient for industrialization, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] The method steps of preparing high-purity glycolide in the present embodiment are as follows:

[0058] Add 305g of glycolic acid crystals to the four-neck flask, raise the temperature to 90°C under nitrogen protection and normal pressure, add 0.03g of stannous chloride after the solid is completely melted, then start vacuuming to reduce the system pressure to 3KPa, and gradually increase the temperature to 200°C , to obtain glycolic acid oligomers after being completely anhydrous. The pressure of the system was adjusted to 800 Pa, and the cracking reaction was carried out at a temperature of 200-260°C. A light yellow liquid was continuously evaporated and turned into a light yellow solid after cooling to obtain crude glycolide with a yield of 92%.

[0059] Heat and dissolve crude glycolide (214g) and 150g ethyl acetate, keep warm for 30min after complete dissolution, then cool down and crystallize, carry out suction filtration at 10°C, dry the solid in vacuum to obtain ...

Embodiment 2

[0061] The method steps of preparing high-purity glycolide in the present embodiment are as follows:

[0062] Add 305g of glycolic acid crystals to the four-neck flask, raise the temperature to 90°C under nitrogen protection and normal pressure, add 0.03g of stannous chloride after the solid is completely melted, then start vacuuming to reduce the system pressure to 1KPa, and gradually raise the temperature to 200°C , to obtain glycolic acid oligomers after being completely anhydrous. The system pressure was adjusted to 500 Pa, and the cracking reaction was carried out at a temperature of 200-260 ° C. A light yellow liquid was continuously evaporated, and after cooling, it became a light yellow solid, that is, crude glycolide was obtained with a yield of 94%.

[0063] Heat and dissolve crude glycolide (219g) and 153g ethyl acetate, keep warm for 30min after complete dissolution, then cool down and crystallize, carry out suction filtration at 5°C, dry the solid in vacuum to obt...

Embodiment 3

[0065] The method steps of preparing high-purity glycolide in the present embodiment are as follows:

[0066] Add 305g of glycolic acid crystals to the four-necked flask, heat up to 90°C under nitrogen protection and normal pressure, add 0.03g of stannous chloride after the solid is completely melted, then start vacuuming and reduce it to 2KPa, and gradually increase the temperature to 200°C. Glycolic acid oligomers were obtained after distilling off completely anhydrous. The system pressure was adjusted to 600 Pa, and the cracking reaction was carried out at a temperature of 200-260°C. A light yellow liquid was continuously evaporated, and after cooling, it became a light yellow solid, that is, crude glycolide was obtained with a yield of 94%.

[0067] Heat and dissolve crude glycolide (219g) and 131g ethyl acetate, keep warm for 30min after complete dissolution, then cool down and crystallize, filter with suction at 6°C, dry the solid in vacuum to obtain a white product, rem...

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Abstract

The invention belongs to the technical field of organic synthesis, and particularly discloses a method for preparing high-purity glycolide. The method comprises the following steps: heating glycollic acid or glycolate under the action of a catalyst to dehydrate or dealcoholize to obtain a glycollic acid oligomer, and then performing heating and decompressing cracking in a depolymerization kettle to obtain crude glycolide; and recrystallizing the crude glycolide with a solvent under the protection of protective gas, carrying out vacuum drying on a crystal substance, and carrying out melt crystallization separation to obtain the polymer-grade glycolide with the purity of more than or equal to 99.9%. The crude glycolide is purified by using a recrystallization and melt crystallization coupling method, so that the cyclic utilization of materials can be realized, no waste is generated, and meanwhile, a high-purity (greater than or equal to 99.9%) glycolide product is prepared at a high yield. The method is a high-efficiency, environment-friendly and high-purity glycolide synthesis method, and is suitable for industrial production.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for preparing high-purity glycolide. Background technique [0002] The problem of environmental pollution (white pollution) caused by the uncontrolled production and use of disposable / disposable petroleum-based plastics (such as: packaging materials, agricultural films, edible plastic wrap, disposable lunch boxes, etc.) has caused worldwide serious concern. Biodegradable polymers based on renewable resources, such as polylactic acid (PLA), polyglycolic acid (PGA), and polylactic-glycolic acid (PLGA), have been recognized by scholars at home and abroad as the most promising candidates for petroleum-based plastics. substitution. Polyglycolic acid (PGA), as a medical absorbable polymer material, has important applications in clinical and medical fields due to its good biodegradability and biocompatibility. As early as the 1930s, Corothers had synthesized polyglycolic aci...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D319/12
CPCC07D319/12
Inventor 康小玲丁永良张飞钟显威郑伯川
Owner SHANGHAI DONGGENG CHEM TECH CO LTD
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