Xerogels, process for their preparation and their use.

摘要

The invention relates to a process for preparing modified SiO2 gels, known as "xerogels", and also to the xerogels thus prepared themselves and their use. The xerogels are prepared by acidifying an aqueous waterglass solution, polymerising the silicic acid thus formed by addition of a base to give an SiO2 gel, substantially washing the water from the gel using an organic solvent, reacting the gel with a silylation agent and then drying it at from -30 to 200 DEG C and at from 0.001 to 20 bar.