Process method for preparing glycolide from glycolate

A technology of glycolic acid ester and process method, which is applied in the direction of organic chemistry, can solve the problems of difficult separation and purification of glycolide, thermal deterioration of depolymerization solvent, and coking in the reactor, so as to shorten the reaction time and avoid solvent pollution , the effect of improving production efficiency

Pending Publication Date: 2020-08-18
SHENZHEN ESUN IND +1
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Problems solved by technology

However, these patents report the addition of high-boiling point polar solvents and solubilizers, heating to form a liquid phase of glycolic acid oligomers, resulting in many depolymerization solvents prone to thermal deterioration, difficult separation and purification of glycolide, and complicated procedures
[0007] Chinese invention patent application (application publication number: CN105622567A, application publication date: 2016-6-1) discloses a high-yield preparation method of glycolide, which mainly solves the low yield of glycolide existing in the prior art The problem, by adopting the following steps: heating under normal pressure to melt glycolic acid, and then raising the temperature of the system to 180-200°C within 1-3 hours to carry out normal-pressure reaction, and distilling off the formed water, and then under t

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  • Process method for preparing glycolide from glycolate

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Effect test

Embodiment 1

[0034] Add 600kg of methyl glycolate and 2.5kg of tin dichloride into the prepolymerization kettle 1, and control the reaction temperature at 140°C. During this process, methanol will be distilled out. After 1.5 hours of reaction, the reaction materials in the prepolymerization kettle 1 will be transferred to Continue the reaction in the final polymerization kettle 2, the vacuum state in the final polymerization kettle 2, the pressure 10KPa, the reaction temperature in the final polymerization kettle 2 is 140°C, the liquid evaporated from the prepolymerization kettle 1 and the final polymerization kettle 2 is collected by the distillation kettle 9, and the distillation kettle Separation and purification are carried out in 9, the low boiling matter methanol is condensed and collected by the recovery tank 6, and the high boiling matter is refluxed into the prepolymerization kettle 1 for continued use. The oligomers formed after the reaction of the materials in the final polymeriz...

Embodiment 2

[0036] Add 600kg of methyl glycolate and 3kg of stannous octoate into the prepolymerization tank 1, and control the reaction temperature at 140°C. During this process, methanol will be evaporated. After 1.5 hours of reaction, the reaction materials in the prepolymerization tank 1 will be transferred to the final polymerization tank. The reaction continues in kettle 2, the vacuum state in the final polymerization kettle 2, the pressure is 8KPa, the reaction temperature in the final polymerization kettle 2 is 140°C, the liquid evaporated from the prepolymerization kettle 1 and the final polymerization kettle 2 is collected by the distillation kettle 9, and in the distillation kettle 9 Separation and purification are carried out, and the low boilers are collected by the recovery tank 6 after the methanol is condensed, and the high boilers are refluxed into the prepolymerization kettle 1 for further use. The oligomers formed after the reaction of the materials in the final polymeri...

Embodiment 3

[0038] Add 600kg of methyl glycolate and 3.6kg of antimony trioxide into the prepolymerization kettle 1, and control the reaction temperature at 130°C. During this process, methanol will be distilled out. After 1 hour of reaction, the reaction materials in the prepolymerization kettle 1 will be transferred to the final The reaction continues in the polymerization kettle 2, the vacuum state in the final polymerization kettle 2, the pressure is 5KPa, the reaction temperature in the final polymerization kettle 2 is 150°C, the liquid evaporated from the prepolymerization kettle 1 and the final polymerization kettle 2 is collected by the distillation kettle 9, and the distillation kettle 9 Separation and purification are carried out in the middle, the low boiling matter methanol is condensed and collected by the recovery tank 6, and the high boiling matter is refluxed into the prepolymerization kettle 1 for further use. The oligomers formed after the reaction of the materials in the...

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Abstract

The invention discloses a process method for preparing glycolide from glycolate, and belongs to the technical field of chemical products. The method comprises the following steps: carrying out primaryreaction on reaction raw materials glycollate and a catalyst in a pre-polymerization kettle; transferring the obtained mixture into a final polymerization kettle connected with a pre-polymerization kettle; oligomers formed by the reaction in the final polymerization kettle flow into a depolymerization kettle to be subjected to a depolymerization reaction; enabling a part of the crude product glycolide obtained in the depolymerization kettle directly to directly flow into a crude product storage tank; and feeding the rest of depolymerized materials into the wiped film evaporator by a circulating pump; separating out a crude product glycolide and other materials in the wiped film evaporator, collecting the crude product glycolide in a crude product storage tank, enabling the other materialsto flow into the depolymerization kettle again for further depolymerization reaction; and purifying the crude product glycolide collected in the crude product storage tank through a melting crystallizer to obtain a pure product glycolide. The polymerization process designed by the invention is divided into two steps, so that the production energy consumption is effectively reduced; meanwhile,, bymeans of the thin-film evaporator, side reactions such as further polymerization and coking caused by the fact that the oligomer stays in the depolymerization kettle for a long time are avoided.

Description

technical field [0001] The invention relates to the technical production of glycolide, which belongs to the technical field of chemical products, in particular to a process for preparing glycolide from glycolate. Background technique [0002] Polyglycolide is a synthetic polymer material with good biodegradability and biocompatibility. Its application is mainly in two aspects of biomedicine and ecology. Glycolide is a ring dimer of glycolic acid. The ring-opening polymerization of glycolide is a relatively mature method for preparing polyglycolic acid. This method can obtain polyglycolic acid products with higher relative molecular weight. Glycolide’s Purity is directly related to the performance of polyglycolic acid. [0003] At present, there are two main synthetic routes of glycolide: the first is to prepare glycolide with chloroacetic acid as raw material; the second is to prepare glycolide with glycolic acid (ester) as raw material. The disadvantage of the first metho...

Claims

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Application Information

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IPC IPC(8): C07D319/12
CPCC07D319/12
Inventor 杨义浒湛露陈锐袁浩周行贵
Owner SHENZHEN ESUN IND
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