Ethylene/1-octadecene copolymerization using η~5: η~1-C_5Me_4-4-R_1-6-R-C _6H_2OTiCl_2 catalysts

摘要

Copolymerization of ethylene with 1-octadecene was studied using η~5:η~1-C_5Me_4-4-R _1-6-R-C_6H_2OTiCl_2 R1 = tBu (1), H (2, 3, 4); R = tBu (1, 2), Me (3), Ph (4) as catalysts in the presence of Al(i-Bu)3 and Ph3CB(C 6F5)4. The effect of the concentration of comonomer in the feed and Al/Ti molar ratio on the catalytic activity and molecular weight of the resultant copolymer were investigated. The substituents on the phenyl ring of the ligand affect considerably both the catalytic activity and comonomer incorporation. The 1/Al(i-Bu)_3/Ph_3C B(C_6F_5)_4 catalyst system exhibits the highest catalytic activity and produces copolymers with the highest molecular weight, while the 2/Al(i-Bu)_3/Ph_3CB(C_6F _5)_4 catalyst system gives copolymers with the highest comonomer incorporation under similar conditions.