Reaction system and method for preparing lactide from oligomer

Abstract

The invention provides a reaction system and method for preparing lactide from an oligomer. The reaction system comprises a lactide synthesis kettle and a reactive distillation tower which are connected in sequence; the reactive distillation tower comprises a distillation section and a lactide deep synthesis section; the rectifying section comprises a light component separation section for separating water, lactic acid and a small amount of oligomer, a product separation section for separating a lactide product, and a heavy component separation section for separating oligomer. According to the reaction system provided by the invention, rectification separation and deep synthesis reaction of lactide are uniformly integrated, so that the reaction route is optimized, the reaction separation efficiency is improved, the product quality and yield are further improved, in addition, the effects of saving the equipment cost and saving the occupied area of the equipment are also achieved, and double benefits are achieved.

Description

technical field [0001] The invention relates to the field of lactide preparation, in particular to a reaction system and method for preparing lactide from oligomers. Background technique [0002] The production, development and utilization of lactide have been paid more and more attention in recent years, mainly because the ring-opening polymerization of lactide is an effective method for preparing high molecular weight polylactic acid. Polylactic acid is a promising biodegradable material. Because the final products of its decomposition in the natural environment are carbon dioxide and water, it is non-toxic and harmless to the environment, and has good biocompatibility and biodegradability. It is an excellent medical polymer material due to its excellent mechanical properties and easy processing and molding. The ring-opening polymerization of lactide is an effective method to prepare high-molecular-weight polylactic acid, and the molecular weight of the polymerization pro...

AI Technical Summary

Problems solved by technology

[0009] Among them, the efficiency of the separation system of the lactide synthesis reaction in the second step is low. Due to the high viscosity of the system and the small separation interface, the generated lactide cannot be taken out in time to make the esterification reaction reach an equilibrium state, causing oligomers to polymerize. direction, reducing the lactide product yield

Long residence time in the reaction process leads to more by-products and indirectly affects the quality of the product

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