Process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a c1 c4 alkyl vinyl ether

Abstract From the Canadian patent

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 …