Functional surface groups for single-site heterogeneous α-olefin polymerization catalysts

E. I. Iiskola*, S. Timonen, T.T. Pakkanen, O. Härkki, J. V. Seppälä

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    25 Citations (Scopus)

    Abstract

    A novel heterogeneous α-olefin polymerization catalyst is prepared by the immobilization of CpZrCl 3 on a chemically modified silica support. The surface modification of silica was carried out by utilizing the saturated gas-solid reactions of a silane coupling agent with a hydrocarbon spacer, Cp(CH 2) 3Si(OCH 2CH 3) 3, and a partially dehydroxylated silica. In gas-solid reactions all reactive surface hydroxyl groups were utilized in bonding the silane coupling agent on silica. The immobilization of CpZrCl 3 on the cyclopentadienyl surface formed on the silica was done using liquid-phase reactions. The prepared materials were characterized by FT-IR spectroscopy. The supported catalyst system has a high activity in ethylene polymerization and can be used to produce polyethylene with a narrow molecular weight distribution in the presence of methylaluminoxane. The catalytic activity was doubled when CpZrCl 3 was immobilized on the cyclopentadienyl surface of SiO 2 compared with the activity of CpZrCl 3 in homogeneous catalysis. However, the direct heterogenization of CpZrCl 3 onto unmodified silica produced a catalyst with a very low activity. The effect of surface modification reactions and the surface structure of a support on the catalyst performance is presented and discussed.

    Original languageEnglish
    Pages (from-to)372-377
    Number of pages6
    JournalApplied Surface Science
    Volume121-122
    DOIs
    Publication statusPublished - Nov 1997
    MoE publication typeA1 Journal article-refereed

    Keywords

    • Atomic layer epitaxy (ALE)
    • Catalyst preparation
    • Metallocene
    • Olefin polymerization
    • Silica
    • Surface modification

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