Effect of SiMe3, SiEt3 Para-Substituents for Exhibiting High Activity, Introduction of Hydroxy Group in Ethylene Copolymerization Catalyzed by Phenoxide-Modified Half-Titanocenes.

Remarkable effects of SiMe 3 , SiEt 3 para -substituent in the phenoxide-modified half-titanocenes, Cp*TiCl 2 (O-2,6- i Pr 2 -4-R-C 6 H 2 ) [R = SiMe 3 ( 6 ), SiEt 3 ( 7 )], toward the catalytic activities in ethylene copolymerizations with 2-methyl-1-pentene, 1-decene, 1-dodecene and with 9-decen-1-ol (DC-OH) have been demonstrated. The activities by 6 , 7 at 50 oC showed higher than those conducted at 25 oC in all cases in the presence of MAO cocatalyst. Efficient synthesis of high molecular weight (HMW) ethylene copolymers incorporating DC-OH (or 5-hexen-1-ol, HX-OH) has been attained in the copolymerization by 7 , which showed better DC-OH (HX-OH) incorporation at 50 oC to afford the HMW copolymers, poly(ethylene- co -DC-OH)s, with high activities (activity 1.21-3.81×10 5 kg-polymer/mol-Ti·h, M n = 6.55-10.0×10 4 , DC-OH 2.3-3.6 mol %).