Method for making hydrophobic silica gels under neutral conditions

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 the pH of a silica hydrosol is adjusted with a base to within a range of pH 3 to pH 7 to facilitate formation of a silica hydrogel. In...

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Bibliographische Detailangaben
Hauptverfasser:	DENG, QIN, HAHN, JAMES RICHARD, BURNS, GARY THOMAS, REESE, CLIFFORD CARLTON
Format:	Patent
Sprache:	eng
Schlagworte:	ADHESIVES CHEMISTRY COMPOSITIONS BASED THEREON COMPOUNDS THEREOF DYES GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS INORGANIC CHEMISTRY METALLURGY MISCELLANEOUS APPLICATIONS OF MATERIALS MISCELLANEOUS COMPOSITIONS NATURAL RESINS NON-METALLIC ELEMENTS ORGANIC MACROMOLECULAR COMPOUNDS PAINTS POLISHES PREPARATION OF CARBON BLACK TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION TECHNICAL SUBJECTS COVERED BY FORMER USPC TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS THEIR PREPARATION OR CHEMICAL WORKING-UP TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS,TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS
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Beschreibung
Zusammenfassung:	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 the pH of a silica 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.