Selenium or tellurium treated silica

摘要

A process comprising treating silica with at least one of selenium or tellurium under nonoxidizing conditions at a temperature of at least 370 DEG C. and a subsequent second step wherein the thus-treated silica is contacted with an oxidizing ambient at a temperature within the range of 370 DEG -900 DEG C. The silica can contain a chromium compound in which case the resulting product is suitable as a catalyst for the production of higher melt flow olefin polymers suitable for such applications as injection molding, and the like requiring a relatively narrow molecular weight distribution.