Composite catalyst for preparing aromatic polycarbonate and application of composite catalyst

Abstract

The invention relates to a composite catalyst for preparing aromatic polycarbonate and application of the composite catalyst. The composite catalyst contains the following raw material components: an organic alkali catalyst and an alkali ionic liquid. The composite catalyst is used in the preparation process of the aromatic polycarbonate, namely, by taking a dihydroxyl compound and dialkyl carbonate as raw materials, synthesizing polycarbonate by using a non-phosgene ester interchange method, wherein the mole ratio of the dihydroxyl compound to the dialkyl carbonate is 1:(1.015-1.1); and the amount of the composite catalyst accounts for 0.5-5% of the mass of the dihydroxyl compound. By adopting the composite catalyst provided by the invention, not only is ester exchange reaction in the polycarbonate synthesis process implemented at a relatively high speed at relatively low temperature, but also the residual amount of the catalyst in a polymerization product is reduced to the minimum extent; and in addition, special properties of a polymeric product are achieved, and meanwhile, adverse influence of application properties of the product, namely the polycarbonate, is avoided to the maximum extent.

Description

technical field [0001] The invention relates to the technical field of polycarbonate synthesis, in particular to a composite catalyst for preparing aromatic polycarbonate and its application. Background technique [0002] As a biodegradable eco-friendly polymer, polycarbonate is characterized by high strength, high toughness, high heat resistance, shock resistance, good processing performance, excellent transparency, dimensional stability, non-toxicity, weather resistance, Known for its electrical insulation, radiation sterilization resistance and mechanical properties, it is a thermoplastic engineering plastic with excellent comprehensive properties. [0003] The trend of polycarbonate industrial production method is to adopt the non-phosgene melt transesterification process, even if the aromatic dihydroxy compound and the carbonic acid diester are directly subjected to the melt transesterification reaction under the action of a catalyst, and finally the aromatic polycarbon...

AI Technical Summary

Problems solved by technology

[0003] The trend of polycarbonate industrial production method is to adopt the non-phosgene melt transesterification process, even if the aromatic dihydroxy compound and the carbonic acid diester are directly subjected to the melt transesterification reaction under the action of a catalyst, and finally the aromatic polycarbonate is prepared; However, the biggest defect of this method is that it has relatively strict requirements on the purity of raw materials, production equipment, and process technology.

In addition, in the process of preparing polycarbonate by melt transesterification, in order to prepare high-molecular-weight polycarbonate, it generally needs to be carried out under high temperature and high vacuum conditions, and the raw material monomers and products remain in a molten state, but as the reaction progresses , especially as the molecular chain of the product increases, the viscosity of the system increases, the mass transfer and heat transfer conditions deteriorate, local overheating is difficult to control, and side reactions such as branching, rearrangement, and crosslinking are prone to occur, resulting in polycarbonate coloring. thereby affecting product quality

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