Interaction between Chromium Oxide and Its Silica-Alumina Support and Activity of the Resulting Polymerization Catalyst

Abstract
Differential thermal analysis and composition, texture, and coverage measurements were carried out and gave evidences for chemical interaction between chromium oxide and the silica-alumina support of an olefin polymerization catalyst. Such interactions are related to the activity vs. propene polymerization and these relations allow to suggest that the active centers involve a layer of trivalent chromium oxide linked to the support by chromosiloxan bonds and covered with one or more layers of hexavalent chromium oxide.