Processes for preparing polyethylene catalysts by heating catalyst precursors

摘要

Ethylene polymers are obtained in enhanced yield in a process for homopolymerizing ethylene or copolymerizing ethylene with an alpha-olefin having 3 to 8 carbon atoms employing a catalyst system comprising (a) a solid titanium (III)-containing precursor, and (b) an organoaluminum activator, by heating the titanium (III)-containing precursor, prior to activating with the organoaluminum activator, at a temperature of 140 DEG -200 DEG C. for a sufficient time to reduce the electron donor level of the precursor from at least about 20 percent to about 80 percent over the electron donor level achieved by drying to constant weight.