INDUSTRIAL PROCESS FOR PRODUCTION OF HIGH-PURITY DIPHENYL CARBONATE

摘要

It is an object of the present invention to provide a specific process that enables a high-purity diphenyl carbonate that can be used as a raw material of a high-quality and high-performance polycarbonate to be produced stably for a prolonged period of time on an industrial scale of not less than 1 ton / hr from a reaction mixture containing a catalyst and reaction by-products that has been obtained through transesterification reaction and the like using a dialkyl carbonate and a phenol as a starting material. Although there have been various proposals regarding processes for the production of reaction mixtures containing aromatic carbonates by means of a reactive distillation method, these have all been on a small scale and short operating time laboratory level, and there have been no disclosures on a specific process or apparatus enabling mass production on an industrial scale from such a reaction mixture to a high-purity diphenyl carbonate that can be used as a raw material of a high-quality and high-performance polycarbonate. According to the present invention, there are provided a high boiling point material separating column A and a diphenyl carbonate purifying column B each comprising a continuous multi-stage distillation column having specified structures, and there is provided a specific process that enables a high-purity diphenyl carbonate which is important as a raw material of a high-quality and high-performance polycarbonate to be produced stably for a prolonged period of time on an industrial scale of not less than 1 ton / hr from a reaction mixture containing the diphenyl carbonate using an apparatus in which these two continuous multi-stage distillation columns are connected together.