PURIFICATION OF CARBONIC ACID DIESTER AND PURIFICATION APPARATUS THEREFOR

摘要

PROBLEM TO BE SOLVED: To efficiently use a heat energy in a method for purifying a carbonic acid diester. SOLUTION: In an extractive distillation process, a mixture containing a carbonic acid diester and a lower alcohol is subjected to extractive distillation with water and separated into an alcohol-containing extract and a distillate carbonic acid diester. The extract is distilled under pressure by a pressure distillation process, separated into water and a distillate component and the distillate component is used as a heating source for the extractive distillation process or the distillation process for preceding or following the extractive distillation process. The distillate carbonic acid diester may be further purified and the distillate component can be used as a heating source for both the extractive distillation process and the purification distillation process. The carbonic acid diester is dimethyl carbonate and the lower alcohol is methanol.