Process for the preparation of polyvinyl alcohol

摘要

Preparation of polyvinyl alcohol by catalytic ester exchange of an alcoholic polyvinyl ester solution and separation of the polyvinyl alcohol (PVA) formed is new. Preparation of polyvinyl alcohol by catalytic ester exchange of an alcoholic polyvinyl ester solution and separation of the polyvinyl alcohol (PVA) formed involving: (a) before starting ester exchange of the polyvinyl ester solution, the acetic acid ester of the alcohol used as solvent is added in such amount that its content is 5-70 wt.% relative to the total amount of alcoholic solution and its acetic acid ester; and (b) the PVA formed on ester exchange is separated from the liquid phase, and the liquid phase is returned in such a portion for ester exchange that the acetic acid ester part in the alcohol/acetic acid ester mixture remains in this portion during ester exchange.