Title

Investigation of the Mechanism of Chain Termination and Transfer by 1, 2-butadiene in the Butyllithium-initiated Polymerization of 1, 3-butadiene in Non-polar Solvents

Document Type

Article

Publication Date

1-1993

Abstract

1,2-Butadiene (BD-1,2) was shown to be a chain terminating/transferring agent in the butyllithium (nBuLi)-initiated polymerization of 1,3-butadiene in hexane solvent by Adams et al. Based on model reactions and circumstantial evidence they proposed that BD-1,2 terminates the polymerization by extracting Li from the living chain end. The lithiated BD-1,2 formed may initiate new chains causing chain transfer or isomerize to lithiated ethylacetylene (system. name: 1-butyne), a nonactive species. This paper proposes a modification of the mechanism suggested by Adams et al. Kinetic investigations of the model reaction between nBuLi and BD-1,2 by infrared spectroscopy have shown that the first, and rate-determining, step is the isomerization of BD-1,2 to ethylacetylene, followed by lithiation. It is proposed that the lithiated ethylacetylene can initiate new chains, thereby causing chain transfer.

Publication Title

Die Makromolekulare Chemie

Volume

194

Issue

1

First Page

187

Last Page

195

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