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Alkyl Zinc Chlorides as New Initiators for the Polymerization and Copolymerization of Isobutene

Authors

  • Antonio Guerrero,

    1. Wolfson Materials and Catalysis Centre, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK
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  • Kevin Kulbaba,

    1. Lanxess Inc., P. O. Box 3001, Sarnia, Ontario, Canada N7T 7M2
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  • Manfred Bochmann

    Corresponding author
    1. Wolfson Materials and Catalysis Centre, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK
    • Wolfson Materials and Catalysis Centre, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK.
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Abstract

Mixtures of RZnCl and tBuCl (R = Et) initiate the polymerization of isobutene in the temperature range of (−35)—(+35) °C. The order of addition of the reagents is important for effective polymerization. Increasing the solubility of the zinc reagent (R = n-octyl) and use of cumyl chloride as co-initiator provides a system that is active from (−90)—(+35) °C. The molecular weights show a remarkably small temperature dependence, EDP = −3.3 kJ · mol−1, compared to EDP = −23 kJ · mol−1 in classical systems (AlCl3, EtAlCl2). The molecular weights increase with decrease in zinc concentration and are consistently higher for n-octyl zinc chloride, as expected for a bulkier, less coordinating counteranion. The polymerizations are not retarded by isoprene addition; homopolymers and copolymers show essentially identical conversions and molecular weights.

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