Butyl lithium can be used in place of aluminium alkyls in catalysts of the A1R3/neodymium complex/A1 alkyl halide type. With catalysts consisting of Al alkyl halide/neodymium complex/BuLi, both order of addition and, in particular, the ratio of catalyst components are critical. Polymer with a high cis content can be made from butadiene and isoprene but conversions are lower and more variable than with standard aluminium alkyl-based catalysts, even when high catalyst concentrations are used. The catalyst can be used as a premix or added to mixed feed as separate components. In both cases the catalyst mixture is somewhat heterogeneous and polymerization rates are improved by shaking or stirring during polymerization.
Посилання на статтю:
A rare earth catalyst for diene polymerization based on butyl lithium / D. K. Jenkins // Polymer. – 1992. – Vol 33. – P. 156-160.