Concerning the reaction of zirconocene dichloride and methylalumoxane: Homogeneous Ziegler-Natta catalytic system for olefin polymerization

The interaction of zirconocene dichloride (Cp₂ZrCl₂) with methylalumoxane (MAO), the two components of homogeneous catalyst for olefin polymerization, was studied by ¹H NMR spectroscopy. Its was found that Cp₂ZrCl₂ is monoalkylated by Al₂(CH₃)₆ present in MAO. The trimethylaluminium contained in MAO appears to be the active species in the alkylation of the zirconocene dichloride. The Cp₂ZrCH₃Cl likely forms, with an excess of MAO, highly polarized species. These are decomposed by a complexing agent of MAO such as KCl.