Effect of lithium alkoxide and hydroxide on polymerization initiated with alkyllithium

Publisher Website
Google Scholar
Abstract
The effects of lithium tert‐butoxide on rates of initiation, propagation, and polymerization of butyllithium‐initiated polymerization of butadiene and styrene were examined. Toluene and cyclohexane were used as solvent and the experiments covered BuLi/‐t‐BuOLi ratios from 1:0 to 1:6. Both polymerization and propagation rates declined in the presence of alkoxide. The initiation rate in cyclohexane increased to a maximum at BuLi/t‐BuOLi ratio of 1:0.5 and then decreased. A mechanism of rapid dissociation of butyllithium oligomer by alkoxide and multiple complexation of butyllithium with excess alkoxide is proposed. Lithium alkoxide also reduced the copolymerization rate but did not affect the copolymerization characteristies. Water reacted with organolithium compound rapidly to form hydroxide. It was found that the hydroxide reacted very slowly with more organolithium compound in hydrocarbon solution to form oxide. Their effects on polymerization were investigated.