Butadiene polymerization with a rare earth compound using a magnesium alkyl cocatalyst: 2

A catalyst was developed for the preparation of high cis polybutadiene consisting of ‘didymium’ versatate — aluminium alkyl halide — magnesium dialkyl. By altering the order of component addition and using neodymium versatate, the catalyst activity and cis content of the polymer were both increased. The aluminium alkyl halide could be replaced by mixtures of aluminium trialkyl plus silicon halides or organic halides. Various additives were tried in order to reduce polymer molecular weight and to alter the molecular weight distribution.