Preparation of monomeric organosilicon esters

Abstract

A process is disclosed which involves the preparation of monomeric organosilicon esters in a much shorter time and at a much higher purification than previously known in the art. More specifically, the process comprises reacting a cyclosilalkoxane having the general formula: ##STR1## wherein R is a monovalent hydrocarbon radical free of aliphatic unsaturation, R' is selected from the group consisting of H and CH.sub.3 and n is an integral of from 1 to 2 inclusive with a free radical polymerizable monocarboxylic acid. The cyclosilalkoxane is contacted with the free radical polymerizable monocarboxylic acid in the presence of a solvent. The solvent forms an azeotropic mixture with the water formed by the reaction. During the reaction, the azeotropic mixture is continuously removed from the reaction. Also present in the reaction solution is a protonating acid catalyst and a free radical polymerization preventing inhibitor. The process further comprises heating the solution to a temperature which forces the reaction to completion at an accelerated rate. During the reaction sufficient oxygen is supplied to the reaction mixture in order to convert the inhibitor present in the reaction mixture from an inactive to an active form. This process forms a substantially pure free radical polymerizable monomeric unsaturated organosilicone ester in about 3 to about 6 hours.