α‐olefin homopolymerization and ethylene/1‐hexene copolymerization catalysed by novel ansa‐group IV complexes/MAO system |
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Authors: | Xiaoxia Yang Yong Zhang Jiling Huang |
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Institution: | The Laboratory of Organometallic Chemistry, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, People's Republic of China |
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Abstract: | The catalytic properties of a set of ansa‐complexes (R‐Ph)2C(Cp)(Ind)MCl2 R = tBu, M = Ti ( 3 ), Zr ( 4 ) or Hf ( 5 ); R = MeO, M = Zr ( 6 ), Hf ( 7 )] in α‐olefin homopolymerization and ethylene/1‐hexene copolymerization were explored in the presence of MAO (methylaluminoxane). Complex 4 with steric bulk tBu group on phenyl exhibited remarkable catalytic activity for ethylene polymerization. It was 1.6‐fold more active than complex 11 Ph2C(Cp)(Ind)ZrCl2] at 11 atm ethylene pressure and was 4.8‐fold more active at 1 atm pressure. The introduction of bulk substituent tBu into phenyl groups not only increased the catalytic activity greatly but also enhanced the content of 1‐hexene in ethylene/1‐hexene copolymerization. The highest 1‐hexene incorporation was 25.4%. In addition, 4 was also active for propylene and 1‐hexene homopolymerization, respectively, and low isotactic polypropylene (mmmm = 11.3%) and isotactic polyhexene (mmmm = 31.6%) were obtained. Copyright © 2007 John Wiley & Sons, Ltd. |
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Keywords: | ansa‐metallocene α ‐olefin ethylene polymerization copolymerization |
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