Verfahren zur Herstellung von cis-1,4-Polybutadien

摘要

Conjugated multi-olefin hydrocarbon polymers, e.g butadiene-1,3, which have at least 80% of the monomer units with a cis 1,4-structure, are made by contacting the monomer with a catalyst comprising (a) a Ni or Co complex compound of an alkylated hydroxy or thiol aromatic organic acid in which the substituent hydrocarbon groups have one or more carbon atoms, (b) a boron fluoride complex and (c) a lithium alkyl or aryl or alkylaryl. When (c) is a lithium alkyl a small amount of water or alcohol may be present in the reaction mixture. The multi-olefine monomer may have 100 to 600 p.p.m. of allene added to it before contact with the catalyst. The polymerization product may be subjected to a heat-treatment to increase its molecular weight. Exemplified (a) components are cobalt and nickel bis-di-isopropyl salicylate. The polymers are recovered by conventional low-pressure methods.