Patent ID: 7598201
Filing Date: 2009-10-06
Classification: B01J,C01B,C01G,C01P,C08F

Abstract:
1. A process for preparing an essentially spherical support for olefin polymerization catalysts, which comprises: a) preparing a hydrogel comprising a cogel of silicon oxide and at least one further metal oxide, b) optionally, washing the hydrogel until the content of alkali metal ions is less than 0.1% by weight, based on the weight of solids, c) extracting water from the hydrogel until the water content is less than 5% by weight, based on the total content of liquid, and d) drying the hydrogel to form a xerogel, wherein step (c) comprises: (1) at least one first extraction down to a water content of less than 50% by weight with a first organic solvent followed by (2) at least one second extraction with a second organic solvent, wherein each of the first and second organic solvents is at least partially miscible with water and is selected from R′OH wherein R′ is an organic radical having 1-6 carbon atoms; and wherein the second organic solvent has at least one carbon atom more or at least one branch, including the heteroatoms, more than the first organic solvent.