Effective activation of metallocene catalysts with supported-type Ph3CClO4 in ethylene polymerization

Supported type cocatalysts using triphenylcarbenium perchlorate (Ph 3 CClO 4 ) were prepared by impregnation on inorganic carrier, magnesium chloride (MgCl 2 ) and applied to ethylene polymerizations with rac-Et[Ind] 2 Zrl 2 . Homogeneous polymerizations with Ph 3 CClO 4 were also carried out for comparison. The activity of homogeneous polymerization was much lower than that obtained with methylaluminoxane (MAO). On the other hand, rac-Et[Ind] 2 ZrCl 2 activated by the supported type Ph 3 CClO 4 /MgCl 2 system displayed high activity comparable to that obtained with MAO. From the results of fractionation and polymerization of the racEt[Ind] 2 ZrCl 2 -Ph 3 CClO 4 /MgCl 2 catalyst system, it was found that the increased activity mainly came from the active species in the supernatant part. UV-vis spectroscopic measurements combined with ICP analysis indicate that the active species in the supernatant fraction are composed of a stoichiometric amount of perchlorate and metallocene catalyst.