PREPARATION OF POROUS, PURE SILICON DIOXIDE AND OF CHROMIUM-OXIDE-ON-SILICON DIOXIDE CATALYSTS

摘要

A process is disclosed for the preparation of porous silicon dioxide by converting a silicon dioxide obtained by flame hydrolysis into a gel using at least the same quantity by weight of water and spray-drying the gel. The process is characterized by the mixing of the gel with at least 15 volume percent, based on the volume of water in the gel, of an alcohol containing 1 to 5 carbon atoms this mixture then being spray dried. The silicon dioxide product gives rise to improved results when used as a carrier for a chromium oxide catalyst for the polymerization of olefins.