Patent ID: 6156223
Filing Date: 2000-12-05
Classification: B01J,C01B,Y10T

Abstract:
A process for the preparation of a xerogel comprising contacting an inorganic wet gel having a polar or non-polar hydrocarbon solvent and less than 5% by weight of water, said gel having a solid gel structure that contains at least about 1 mole percent of hydroxyl moieties with a silicon-nitrogen compound which is present at an amount giving a concentration ratio of the silicon-nitrogen compound to the hydroxyl moieties of at least about 1:1, whereby the silicon-nitrogen compound reacts with the hydroxyl moieties in the gel to obtain a reaction product, further providing that the silicon-nitrogen compound had a formula of (Si(C.sub.1-6)(R.sup.2).sub.z --N(R.sup.1).sub.y).sub.x wherein each R.sup.1 can independently be a hydrogen, a C.sub.1-6 moiety, or a Si(C.sub.1-6).sub.3 moiety and each R.sup.2 can independently be a C.sub.1-6 moiety or an N(R.sup.1).sub.2 moiety, and wherein each C.sub.1-6 moiety in the formula and in R.sup.1 and R.sup.2 has from 1 to 6 carbon atoms and can be a linear, branched or cyclic, saturated, unsaturated or aromatic hydrocarbon moiety in which each C.sub.1-6 only has hydrogen as a substituent, and, in the formula, x can be any whole number from 1 to 20, z can be 1 or 2, and y can be 1 or 2 and further the said silicon-nitrogen compound can have a molecular structure which is linear, branched, cyclic or contains cyclic sections, and drying the reaction product at atmospheric pressure to obtain the xerogel.