METHOD FOR MAKING HYDROPHOBIC SILICA GELS UNDER NEUTRAL CONDITIONS

摘要

The present invention is hydrophobic silica gels and a method for their preparation under neutral conditions. The method comprises two steps, where in the first step of the pH of a silic hydrosol is adjusted with a base to within a range of pH 3 to pH 7 to facilitate formation of a silica hydrogel. In the second step, the silica hydrogel is contacted with an organosilicon compound in the presence of a catalytic amount of a strong acid to effect hydrophobing of the silica hydrogel. In a preferred method, in a third step the hydrophobic silica gel is contacted with a sufficient quantity of a water-immiscible organic solvent to convert the hydrophobic silica hydrogel into a hydrophobic silica organogel.