Polycarbonate synthesis process

Abstract

A polycarbonate synthesis process comprises steps as follows: S1, a raw material mixing stage: melt isosorbide and dialkyl carbonate are stirred and uniformly mixed in a raw material mixing tank; S2, an ester exchange reaction stage: a tower reactor located behind the raw material mixing tank is taken as an ester exchange reactor, and released hydroxyl and aryl reaction products can be removed continuously; S3, a pre-polymerization reaction stage: a kettle pre-polycondensation reactor is arranged behind the ester exchange reactor, a pre-polymerization product is generated in the pre-polycondensation reactor, and meanwhile, released hydroxyl and aryl reaction products are removed continuously; S4: a polycondensation reaction stage: a hydraulic driven horizontal disk polycondensation reactor located behind the pre-polymerization reactor performs microwave processing on a pre-polycondensation product, and the pre-polycondensation product is subjected to polycondensation to form polycarbonate melts. The released hydroxyl and aryl reaction products are removed continuously, so that reaction balance is pushed in the positive direction, the pre-polycondensation product is heated through microwaves in the polycondensation stage, and the reaction rate can be effectively increased.

Description

technical field [0001] The invention relates to the chemical field, in particular to a polycarbonate synthesis process. Background technique [0002] Polycarbonate (referred to as PC) is a high molecular polymer containing carbonate groups in the molecular chain. According to the structure of the ester group, it can be divided into aliphatic, aromatic, aliphatic-aromatic and other types. Among them, the low mechanical properties of aliphatic and aliphatic-aromatic polycarbonates limit their application in engineering plastics. At present, only aromatic polycarbonate has been produced industrially. Due to the special structure of polycarbonate, it has become the fastest-growing general-purpose engineering plastic among the five major engineering plastics. [0003] Because the traditional polycarbonate synthesis process is relatively mature, it is still widely used at present, such as the use of isosorbide and carbonic acid diester esterification reaction in the molten state...

AI Technical Summary

Problems solved by technology

[0003] Because the traditional polycarbonate synthesis process is relatively mature, it is still widely used at present, such as the use of isosorbide and carbonic acid diester esterification reaction in the molten state, and then the finished polycarbonate is obtained through prepolymerization reaction and polycondensation reaction. Although the yield of polycarbonate is high in this process, its synthesis reaction takes a long time and consumes a lot of energy.

At the same time, because the melt transesterification process is carried out at high temperature and high viscosity, there are many side reactions, which affect the color and quality of the product, and the side reactions generated make the selection of catalysts particularly important. The impact of stability requires adding a catalyst quenching step, which will increase the difficulty of the process and hinder the application of melt transesterification supply

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