Process for the preparation of esters or alcoholates by water separation

摘要

A process for removing water from reaction mixtures of alcohols with acids or acid anhydrides or with aqueous metal hydroxide solutions, by vapour permeation/pervaporation at the b.pt. of the mixture. The process comprises: (a) placing the reactant with the lowest b.pt. (I) in the reactor, together with the other reactant (II), with or without catalyst in the case of esterification reactions and using less than the stoichiometric amount of (I) (with respect to II), (b) heating to boiling and feeding the resulting vapour mixture (optionally with any condensed phase which is formed) to a membrane on which the water is separated, (c) returning the water-depleted vapour to the reaction mixture and (d) adding more (I) during the reaction.