Preparation of di:carboxylic acid di:ester(s)

摘要

A process for the preparation of dicarboxylic acid diesters of lower alcohols by heating a mixture of dicarboxylic acid and lower alcohol in the presence of a catalyst whilst removing water generated during the reaction, comprises: (1) the dicarboxylic acid, lower alcohol and catalyst are supplied continuously to a first esterification step in which the acid is partially esterified ; (2) the partially esterified reaction mixture is supplied continuously to a second esterification stage from which a gaseous mixture of lower alcohol and water generated during the reaction is removed ; (3) the liquid esterified mixture is supplied continuously into the side of a distillation column ; (4) the diester is removed from the top of the column and the monoester-rich product is removed from the base of the column continuously; and (5) the monoester-rich product is returned to step (1) and/or (2).