Stereoregular Polymerization of Butadiene with Alkylaluminum Chlorides and Cobalt Octoate

Abstract

Abstract The requirement of water or oxygen to activate the diethylaluminum chloride co-catalyst used with a cobalt compound to produce 98 per cent cis-1,4 poly-butadiene was reported previously. Activation is considered to form two alkylaluminum compounds differing in Lewis acidity. Several reactions presumed to lead to the formation of the higher acid were carried out with a minor proportion of the diethylaluminum chloride by partial dealkylation with organic hydroperoxide, halogen, tertiary alcohol, organic halide or aluminum. Water is neither necessary nor desirable in the ethylaluminum sesquichloride-cobalt octoate catalyst system. Polar solvents do not appreciably alter the cis-1,4 catalysis with diethylaluminum chloride/water/cobalt octoate, but do decrease the rate or extent of polymerization with increasing dielectric constant of the solvent. A mechanism of cobalt catalysis of butadiene polymerization is proposed.