Enhanced Productivity of a Supported Olefin Trimerization Catalyst

Abstract

Treatment of dry silica with methylaluminoxane (MAO) followed by (FI)TiCl_3 (FI = (N-(5-methyl-3-(1-adamantyl)salicylidene)-2′-(2″-methoxyphenyl)anilinato) gives a heterogeneous supported ethylene trimerization catalyst, s(FI)Ti, which exhibits productivity more than an order of magnitude higher than its homogeneous analogues. This increase in productivity is attributed to a decreased rate of catalyst decomposition, a process that is proposed to occur via comproportionation to an inactive TiIII species; immobilization retards this process. In addition, s(FI)Ti catalyzes trimerization of α-olefins with high selectivity. Based on regioisomer distributions, catalysis by s(FI)Ti involves the same active species as the previously reported homogeneous systems (FI)TiR_2Me/B(C_6F_5)_3 (R = Me, CH_2SiMe_3, CH_2CMe_3).