Polynuclear catalysis: Enhancement of enchainment cooperativity between different single-site olefin polymerization catalysts by ion pairing with a binuclear cocatalyst

被引:80
作者
Abramo, GP [1 ]
Li, LT [1 ]
Marks, TJ [1 ]
机构
[1] Northwestern Univ, Dept Chem, Evanston, IL 60208 USA
关键词
D O I
10.1021/ja020870b
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
A new multicenter ethylene polymerization process is described whereby two different single-site catalysts, one competent for producing vinyl-terminated oligomers or macromonomers and one competent for producing high-molecular weight ethylene-α-olefin copolymers, are held in close spatial proximity via ion-pairing with a dianionic binuclear bis-borate cocatalyst. Ethylene polymerizations mediated by stoichiometrically appropriate quantities of Me2Si(tBuN)(η5-3-ethylindenyl)ZrMe2 and Me2Si(tBuN)(η5-C5Me4)TiMe2 activated by the bis-borate cocatalyst [Ph3C+]2[1,4-(C6F5)3BC6F4B(C6F5)3-2] yield a more homogeneous polyethylene product when compared to control polymerizations using the mononuclear activator [Ph3C+][B(C6F5)4-]. The bulk and spectroscopic properties of the polymer produced using the binuclear activator are consistent with highly branched polyethylene. Copyright © 2002 American Chemical Society.
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页码:13966 / 13967
页数:2
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