PROCESS FOR MAKING ETHANOL SOLUTIONS OF ALKYL HALF-ESTERS OF COPOLYMERS OF MALEIC ANHYDRIDE AND A C1 C4 ALKYL VINYL ETHER

摘要

2083950 9204405 PCTABS00011 What is described herein is a process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a C1-C4 alkyl vinyl ether which are benzene and acetone-free. The invention is characterized by (a) precharging a reactor with excess C1-C4 alkyl vinyl ether as both monomer reactant and solvent, and a free radical polymerization intiator, at a reaction temperature; (b) feeding the alkyl half-ester of maleic anhydride formed by reaction of substantially one mole of maleic anhydride and substantially one mole of alkanol into the precharged reactor to form the desired alkyl half-ester of the alternating copolymer of maleic anhydride and the C1-C4 alkyl vinyl ether in excess alkyl vinyl ether as solvent; (c) cooling the reactor to room temperature; and (d) introducing ethanol solvent into the reactor and removing excess alkyl vinyl ether to form the desired half-ester copolymer in ethanol solution.