Cationic Polymerization of t-Butyl Propenyl Ether and Reaction of Its Polymer

Abstract

t-Butyl propenyl ether (tBPE) (cis-isomer) was polymerized by BF₃·O (C₂H₅) ₂ to compare with the polymerizability of t-butyl vinyl ether (tBVE). Although a homopolymer could be produced from tBPE, both its rate of polymerization and molecular weight were low. Also in the copolymerization of tBPE with tBVE, tBVE was less reactive than tBVE. In vinyl ethers having such a bulky alkoxy group as t-butoxy group, the introduction of methyl group into β-position decreased the reactivity of vinyl ethers due to the steric hindrance. This behavior is just reverse of n-alkyl propenyl ethers.
Crystalline poly-tBPE could be obtained in the polymerization in toluene at low temperature, but in methylene chloride only amorphous polymer was obtained. These polymers were converted to poly- (β-methyl vinyl acetate) by acetylating agent (acetic anhydride and ZnCl₂). However, pure poly- (β-methyl vinyl alcohol) could not be obtained by saponification of poly- (β-methyl vinyl acetate).