The preparation process of sìlica hydrophobic gels modified by organossilicatos under neutral conditions.

摘要

Invention patent: b "preparation process of su00eclica hydrophobic gels modified by organossilicatos under neutral conditions" d .The present invention relates to silica gels modified by organossilicato hydrophobic and a process for preparing the same under neutral conditions.The process comprises two steps.As in the first stage, the pH of a hidrossol silica modified by organossilicato is adjusted with a base to a pH range 3 to pH 7 to facilitate formation of a silica hydrogel modificADO for organossilicato.In the second step,The hydrogel of silica modified by organossilicato is put in contact with a organossilu00edcio compound in the presence of a catalytic amount of a strong acid to make the hidrofobizau00e7u00e3o hiDrogel silica modified by organossilicato to form a hydrophobic silica gel modified by organossilicato having a surface area within a range of 100 m2 / g to 850 m2 / g,In the dry state.A preferred process,The hydrophobic silica hydrogel modified by organossilicato is put in contact with a sufficient amount of organic solvent immiscible with water to convert the silica hydrogel hidrofu00f3bicThe modified by organossilicato in organogel silica modified by organossilicato.Can be added a compound of cerium or iron soluble in water in the second stage, to improve the heat stability of hydrophobic silica gel modified by organossilicato.