Patent ID: 6129949
Filing Date: 2000-10-10
Classification: C01B,C04B

Abstract:
Process for the preparation of organically modified aerogels, comprisinga) the preparation of a silicic acid sol of pH .ltoreq.4.0 from an aqueous water glass solution by means of at least one organic and/or inorganic acid, with at least one acid forming difficultly soluble salts at temperatures between 0.degree. C. and 30.degree. C. with cations of the water glass in the silicic acid sol;b) extensively precipitating the resulting difficultly soluble salts at temperatures between 0.degree. C. and 30.degree. C., and separating them from the silicic acid sol;c) polycondensing the resulting silicic acid sol by the addition of a base, to form a SiO.sub.2 gel;d) washing the gel obtained in Step c) with an organic solvent until the water content of the gel is .ltoreq.5% by weight;e) modifying the surface of the gel obtained in Step d) with at least one C.sub.1 -C.sub.6 alcohol; andf) drying the surface-modified gel obtained in Step e).