Styrene polymerization with half-sandwiched titanocene trichloride catalysts combined with alkylaluminum-Ph₃CB(C₆F₅)₄ cocatalyst systems

Half-sandwiched titanocene trichloride (Cp′TiCl₃; Cp′ = cyclopentadienyl, Cp; pentamethylcyclopentadienyl, Cp^*; indenyl, Ind) combined with an alkylaluminum (triisobutylaluminum, diisobutylaluminum hydride, or trioctylaluminum)/Ph₃CB(C₆F₅)₄ cocatalyst system has been examined for polymerization of styrene. Syndiospecific polymerization of styrene proceeded under limited polymerization conditions. The maximum productivity of syndiotactic polystyrene was attained under the following conditions: Al/Ti molar ratio = 20 (mol/mol), polymerization temperature = 40-50 °C. The nature of alkylaluminum compounds and the ligand structure of the catalysts affected the range of the polymerization temperature in which proceeds the syndiospecific polymerization of styrene.