Studies of the active complex of a soluble catalyst. I. Ti(O‐<i>n</i>‐Bu)₄–AlEt₃ system

Abstract

Abstract The characterization of an active complex in a soluble Ti(O‐ n ‐Bu) 4 ‐AlEt 3 system is reported in connection with its polymerization activity for styrene. The catalytic activity strongly depends on the Al/Ti ratio in the catalytic system. The optimal Al/Ti ratio for polymerization reaction is estimated as 1,5. Active titanium species are present in trivalent state. Further reduction of titanium species to a valency of less than 3 results in no activity for styrene polymerization. Two types of active species are detected by the IR and ESR studies of the catalytic system. One is Ti(O‐ n ‐Bu) 2 Et, and the other is a complex formed by 1 mole of Ti(O‐ n ‐Bu) 2 Et and 2 moles of ( n ‐BuO)‐AlEt 2 . The differences in activity between these are now under investigation. IR and ESR studies of the Ti(O‐ n ‐Bu) 3 ‐AlEt 3 system are also reported.