Vinyl polymerization by lithium organocuprates

Abstract

Abstract Vinyl polymerizations initiated by lithium organocuprates under several conditions were investigated. It was observed that this catalyst was effective in the polymerization of specific monomers such as α,β‐unsaturated nitrile and carbonyl analogues. The rate of polymerization was rapid but retarded by the addition of pyridine, nitrobenzene, or hydroquinone. Polymerization of methyl methacrylate (MMA) with lithium di‐ n ‐butylcuprate as initiator produces predominantly isotactic poly(methyl methacrylate) (PMMA) in toluene. The overall activation energy was estimated as 3.5 kcal/mol deg. Lithium di‐ n ‐butylcuprate exerts a higher stereoregulating effect on the addition of monomers than other organolithium initiators. It is proposed that polymerization proceeds via a coordinated anionic mechanism.