The Effect of SiMe3and SiEt3ParaSubstituents for High Activity and Introduction of a Hydroxy Group in Ethylene Copolymerization Catalyzed by Phenoxide-Modified Half-Titanocenes

Remarkable effects of SiMe(3)and SiEt(3)para-substituents in the phenoxide-modified half-titanocenes, Cp*TiCl2(O-2,6-Pr-i(2)-4-R-C6H2) [R=SiMe3(6), SiEt3(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 by6,7at 50 degrees C showed higher than those conducted at 25 degrees C 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 by7, which showed better DC-OH (HX-OH) incorporation at 50 degrees C to afford the HMW copolymers, poly(ethylene-co-DC-OH)s, with high activities (activity 1.21-3.81x10(5) kg-polymer mol(-1)-Ti h, M-n=6.55-10.0x10(4), DC-OH 2.3-3.6 mol %).