Study On The Technology Of Synthesis Of Dimethyl Carbonate By Transesterification

A set of 100kt·a^-1 non-carbonyl chloride method polycarbonate installation will be imported during eleventh five-year plan by Jilin Petro-Chemical Company,Ltd.Petrochina,by the time it needs 80kt·a^-1 diphenyl carbonate,40kt·a^-1 dimethyl carbonate and 40kt·a^-1 ethylene carbonate as material assure.It holds 60kt·a^-1 epoxyethane installation with Jilin Petro-Chemical Company,Ltd.Petrochina to provide enough raw material for synthesis of ethylene carbonate,in other words,it will provide enough raw material for synthesis of dimethyl carbonate.So this research work will be very important for development of Jilin Petro-Chemical Company,Ltd.Petrochina.In this paper,possible side reaction was confirmed through test in reaction system firstly and then thermodynamics calculation was carried out for main reaction and two side reaction.The result of calculation showed that the impetus of reaction thermodynamics of side reaction was mighty small without advantage in reaction competition.Main reaction is heat absorbing reaction and high temperature is favourable for positive direction;side reaction is exothermal reaction and low temperature is favourable for positive direction.For guide of real manipulation:it need to remove reaction product rapidly to the best of our abilities at the same time of reaction to avoid side reaction.Namely using non-homogeneous catalyst,utilizing reactive distillation technics,removing product at the same time of reaction,making selectivity of dimethyl carbonate greater than 83 percent and conversion ratio of ethylene carbonate greater than 99 percent.Plate-to-plate calculation was done with reactive rectifier on the basis of thermodynamics calculation.The result showed that rectifying section needs ninteen ideal plates,reaction section needs six ideal plates and stripping section need eighteen ideal plates,it basically tallys with results of test.Technical economy analysis was done for pilot test installation of 5kt/a dimethyl carbonate with transesterification on the basis of study of small-scale test,thermodynamics calculation and reactive rectifier calculation.The result showed that synthesis of dimethyl carbonate with transesterification has good economy.