Abstract: Catalyst residues of a transition metal compound and an organometalliccompound contained in a polymer slurry are deactivated by contact with anhydrous carbon dioxide. Preferably the contacting is carried out in a transfer line connecting the reaction zone with a zone of sufficiently lower pressure that flashing of diluent occurs in the transfer line to assure mixing of the carbon dioxide and the catalyst residues.

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

Abstract: High melt flow olefin polymers suitable for such applications as injection molding, and the like requiring a narrow molecular weight distribution are produced using a catalyst made by treating a chromium catalyst on a silica-containing base with a sulfur-containing material, and thereafter reoxidizing.

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