Preparation method of glycolide

Abstract

The invention discloses a preparation method of glycolide. According to the preparation method, high purified glycolic acid crystal is taken as a raw material, and high-purity high-yield glycolide crystal can be synthetized through a series of steps such as dehydration polycondensation, melt phase polycondensation, depolymerization reaction and recrystallization purification. Glycolic acid oligomer is generated through glycolic acid polycondensation, and almost all the glycolic acid oligomers are depolymerized for preparing the glycolide under the action of a high efficient catalyst, the usage amount of the catalyst is low, the preparation technology is simple, the yield is high and the preparation method has industrial production potential.

Description

technical field [0001] The invention relates to a preparation method of glycolide, which belongs to the technical field of preparation of cyclic compounds. Background technique [0002] Due to their good biocompatibility and biodegradability, polyglycolic acid and glycolic acid copolymers are widely used in the field of controlled drug release, plastic surgery, dentistry, tissue engineering, etc. These complex applications require polymers to be Degradation or absorption within a certain period of time, and the control of the degradation time needs to be controlled through primary structural characteristics such as polymer skeleton and functional characteristics, or through thermal properties such as morphology, tensile strength or modulus, glass transition temperature or melting point, or degradation temperature. The physical and chemical properties of these polymers depend on structural characteristics such as skeleton and crystal packing mode. [0003] Contains—C...

AI Technical Summary

Problems solved by technology

CN101054371A prepares glycolide monomer by melting and depolymerizing oligomeric glycolic acid, but the purity requirement of glycolic acid crystals is high, the amount of catalyst is relatively large, and the yield is relatively low

And CN101054371A has adopted double catalyst depolymerization low-molecular-weight polyglycolic acid to prepare glycolide, condensation catalysts or transesterification catalysts such as metals or metal compounds of IV, V, VII main group and IIB subgroup and tin halide or organic acid Compounds, or rare earth metal complexes, or zinc halides or organic zinc compounds, or iron halides or organic iron compounds, can produce glycolide in high yields, but this method requires high purity of raw materials, and melt polycondensation The temperature is high and the catalytic system is complicated, which does not meet the requirements of simple and energy-saving industrial preparation

[0008] At present, no matter in the process of preparing glycolide by solution depolymerization or melt depolymerization of oligoglycolic acid, the preparation process is relatively complicated, and the yield is generally not high, which greatly limits the industrial application of these preparation methods. Although the above patents The optimization of the preparation process of glycolide is disclosed, but the research on the preparation process of glycolide that is environmentally friendly, mild in conditions, and efficient in the preparation process is still worth studying