Methods of preparing active chromium/alumina catalysts via treatment with sulfate and polymers produced using the chromium/alumina catalysts

摘要

Methods of preparing a polymerization catalyst are provided that include contacting a support comprising alumina with a sulfating agent and with chromium. The support can be calcined after loading the sulfating agent and the chromium on the support. Alternatively, the sulfating agent can be loaded on the support while calcining it. Alternatively, the support can be calcined after contacting it with the sulfating agent and before contacting it with an organochromium compound. Catalysts compositions comprising chromium and a sulfate treated alumina support that were formed by the foregoing method are provided. The catalyst compositions have increased catalyst activity. Methods of producing a polymer include contacting at least one olefin with the catalyst compositions are provided. The polymer compositions exhibit relatively low levels of long chain branching and relatively high molecular weights.