Reduction and reoxidation of cogel or self-reduced catalyst

摘要: High melt flow olefin polymers suitable for such applications as injection molding, and the like requiring a narrow molecular weight distribution are produced using catalyst made by reducing reoxidizing chromium on either titanium-silica cogel or self-reduced silica-containing composition. In first embodiment, formed coprecipitating silica titania, containing compound, is treated in nonoxidizing atmosphere, CO, hydrogen, N 2 material decomposable to these materials, thereafter reoxidized. second titanium-free heated air dry oxidize after which it an inert atmosphere wherein composition give lower valence state. The resulting then ambient reoxidized embodiment.