The Effect of SiMe<sub>3</sub> and SiEt<sub>3</sub><i>Para</i> Substituents for High Activity and Introduction of a Hydroxy Group in Ethylene Copolymerization Catalyzed by Phenoxide‐Modified Half‐Titanocenes
Suphitchaya Kitphaitun, Qing Yan, Kotohiro Nomura
Abstract
Abstract Remarkable effects of SiMe 3 and SiEt 3 para‐substituents 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 °C showed higher than those conducted at 25 °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 by 7 , which showed better DC‐OH (HX‐OH) incorporation at 50 °C to afford the HMW copolymers, poly(ethylene‐co‐DC‐OH)s, with high activities (activity 1.21–3.81×10 5 kg‐polymer mol −1 ‐Ti h, M n =6.55–10.0×10 4 , DC‐OH 2.3–3.6 mol %).