TWICE-AGED POROUS INORGANIC OXIDES, CATALYSTS, AND POLYMERIZATION PROCESSES

摘要

A silica-titania cogel or silica-titania-chromium tergel is first aged at a substantially neutral pH, then aged at an alkaline pH, and then spray dried or azeotrope dried to form a xerogel. Optionally, a pore- preserving agent can be added prior to drying. The cogel can be impregnated with a chromium compound. The chromium-containing catalyst is activated by calcination. The activated catalyst can be used as a polymerization catalyst to polymerize mono-1-olefins.