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Synthesis method of high-purity glycolide

A synthesis method and technology of glycolide, which is applied in the field of synthesis of high-purity glycolide, can solve the problems of low production efficiency, large amount of three wastes, inconvenient industrialization, etc.

Active Publication Date: 2021-08-20
SHANGHAI DONGGENG CHEM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0013] In view of the above-mentioned shortcoming of prior art, the object of the present invention is to provide a kind of synthetic method of high-purity glycolide, for solving the synthesis cost of glycolide in prior art is higher, production efficiency is low, energy consumption is high , large amount of three wastes, not convenient for industrialization, etc.

Method used

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preparation example Construction

[0033] The invention provides a method for synthesizing high-purity glycolide, comprising the following steps: heating glycolic acid or glycolic acid ester under the action of a catalyst to dehydrate or dealcoholize to obtain glycolic acid oligomers; The crude glycolide obtained by pressure cracking is rectified under high vacuum, and the rectified product is separated by melt crystallization to obtain polymer grade glycolide with a purity ≥ 99.9%.

[0034] Further, the glycolate is at least one selected from methyl glycolate, ethyl glycolate, propyl glycolate, and butyl glycolate.

[0035] Further, the catalyst is selected from at least one of tin compounds, antimony oxide, and zinc compounds; specifically, the tin compounds are selected from stannous chloride, stannous octoate, stannous chloride dihydrate, At least one of tin lactate and stannous benzoate, the zinc compound is selected from at least one of zinc chloride, diethyl zinc, zinc acetate dihydrate, and zinc lactate...

Embodiment 1

[0049] The synthetic method of high-purity glycolide in the present embodiment comprises the steps:

[0050] 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 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%.

[0051] Add the crude glycolide (219g) into the rectification device under the protection of nitrogen, then vacuumize and reduce the pressure of the system to 500Pa; begin to heat up to 150°C, during which the former f...

Embodiment 2

[0053] The preparation of thick glycolide is with embodiment 1.

[0054] Add crude glycolide (219g) in the rectification device under the protection of nitrogen, then evacuate and reduce the pressure of the system to 500Pa; begin to heat up to 160 ° C, during which the previous fraction and product collection are carried out; the former fraction and still residue Apply to the next batch of reactions. Purify the rectified product through a melting crystallizer. The main operations include film formation, cooling crystallization, heating up to sweat, collecting product and discharging mother liquor, etc. The specific process is: heating glycolide to 88°C for melting, followed by 0.4°C / Min to carry out cooling and crystallization, control the temperature difference at 20°C; then heat up and sweat at 0.4°C / min, control the temperature difference at 10°C, and eliminate the sweating liquid; finally heat up and melt to collect the glycolide product, and apply the mother liquor to th...

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Abstract

The invention belongs to the technical field of organic synthesis, and particularly discloses a synthesis method of high-purity glycolide. The synthesis method comprises the following steps: heating glycollic acid or glycolate under the action of a catalyst to realize dehydration or dealcoholization so as to obtain a glycollic acid oligomer, and then carrying out heating, decompressing and cracking in a depolymerization kettle to obtain crude glycolide; and rectifying the crude glycolide under high vacuum, and subjecting a rectification product to melt crystallization separation to obtain the polymer-grade glycolide with a purity of greater than or equal to 99.9%. According to the synthesis method disclosed by the invention, the crude glycolide is purified by using a rectification-melt crystallization coupled method, no reagent is added, materials can be recycled, and a high-quality glycolide product can be obtained at a high yield. The method is an efficient, 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 synthesizing 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 ...

Claims

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Application Information

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