Comonomer enhancement effect of 1-hexene in ethylene copolymerization catalyzed over MgCl2/THF/TiCl4 catalysts

Authors

  • I. Kim,

    Corresponding author
    1. Department of Chemical Engineering, University of Ulsan, P.O. Box 18, Ulsan, Kyungnam 680-749, South Korea
    • Department of Chemical Engineering, University of Ulsan, P.O. Box 18, Ulsan, Kyungnam 680-749, South Korea
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  • J. H. Kim,

    1. Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, 373-1, Kusong-dong, Yusong-ku, Taejon, South Korea
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  • H. K. Choi,

    1. Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, 373-1, Kusong-dong, Yusong-ku, Taejon, South Korea
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  • M. C. Chung,

    1. Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, 373-1, Kusong-dong, Yusong-ku, Taejon, South Korea
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  • S. I. Woo

    Corresponding author
    1. Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, 373-1, Kusong-dong, Yusong-ku, Taejon, South Korea
    • Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, 373-1, Kusong-dong, Yusong-ku, Taejon, South Korea
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Abstract

Homo- and copolymerization of ethylene were performed by using a catalyst system composed of TiCl4/THF/MgCl2 complex activated with AlEt3 at 70°C and 3 atm. To investigate the effect of the compositional difference of the catalyst on the rates of homo- and copolymerization and on the reactivity in ethylene–hexene copolymerization, a series of six catalysts with different compositions (Mg/Ti = 0.4–16.5) were prepared by coprecipitation. The catalytic activity in ethylene polymerization increased sharply with the Mg/Ti ratio from 21 (Mg/Ti = 0.4) to 1477 kg PE/g-Ti h (Mg/Ti = 16.5). The activity in copolymerization with 1-hexene also increased with Mg/Ti ratio. The values of r1 were 120, regardless of Mg/Ti ratios within the experimental error range. Enhancement of the polymerization rate by the addition of 1-hexene in the reaction medium was observed only for the catalysts of low Mg/Ti ratio. This unusual effect of 1-hexene on the polymerization rate was explained by chemical and physical processes that occurred during polymerization. © 1993 John Wiley & Sons, Inc.

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