Abstract: The present invention relates to a process which comprises the non-hydrolytic transformation of an aluminoxane precursor composition, comprising carbon-to-oxygen bonds which can be alkylated by an alkylaluminum moiety, into a catalytically useful aluminoxane composition. In one embodiment of this invention, the catalytically useful aluminoxane composition is a polymethylaluminoxane composition substantially free of trimethylaluminum. The intermediate precursor is formed by the reaction of a trialkylaluminum compound, or a mixture of trialkylaluminum compounds, and a compound containing a carbon-to-oxygen bond, such as an alcohol, ketone, carboxylic acid, or carbon dioxide. Either unsupported or supported polymethyl-aluminoxane compositions can be formed.

Abstract: A hydrocarbon-soluble alkylaluminoxane composition, such as, methylaluminoxane or even a modified methylaluminoxane, can be prepared by preparing an alkylaluminoxane precursor via non-hydrolytic means, such as, by treating at least one trialkylaluminum compound with a compound containing an oxygen-carbon bond, adding to that precursor an effective amount of an organoaluminum compound which prevents formation of insoluble species, such as, a trialkylaluminum compound where each alkyl group contains two or more carbon atoms, and converting that modified precursor to an alkylaluminoxane, such as, by thermolysis. In a distinct embodiment of the invention, if an insoluble methylaluminoxane product is formed using the non-hydrolytic technique, it can be solubilized by treatment with a solubilizing amount of an alkylaluminoxane, prepared by either hydrolytic or non-hydrolytic means, wherein the alkyl moieties contain two or more carbon atoms.