The Effect of SiMe3 and SiEt3 Para Substituents for High Activity and Introduction of a Hydroxy Group in Ethylene Copolymerization Catalyzed by Phenoxide-Modified Half-Titanocenes |
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| Authors: | Suphitchaya Kitphaitun Qing Yan Prof Dr Kotohiro Nomura |
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| Institution: | Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami Osawa, Hachioji, Tokyo, 192-0376 Japan |
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| Abstract: | Remarkable effects of SiMe3 and SiEt3 para-substituents in the phenoxide-modified half-titanocenes, Cp*TiCl2(O-2,6-iPr2-4-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 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 1.21–3.81×105 kg-polymer mol−1-Ti h, Mn=6.55–10.0×104, DC-OH 2.3–3.6 mol %). |
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| Keywords: | ethylene copolymerization half-titanocenes ligand effect polyolefin-containing polar groups titanium catalyst |
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