Catalytic composition for polymerization of olefins.

A process for the preparation of a catalyst system, comprising the steps of: a) combining a Lewis base, at least one organic compound having at least one functional group containing active hydrogen, and a first organometallic component containing at least an organometallic compound with a particulate support material, to provide an intermediate composition; b) combining the intermediate composition with one or more metallocene compounds, where the stoichiometric ratio of organic compound having active hydrogen to the first organometallic component containing at least one organometallic compound varies from 3: 1 to 5: 1.