Polyfunctional organosilane treatment of silica

Abstract

The present invention provides a method of treating silica wherein silica is reacted with a di- or tri-functional organosilane in an aqueous acid medium to provide a crude organosilane-capped silica product containing organosilicon impurities. The organosilicon impurities are extracted from the crude product with an organic liquid to provide a purified product consisting essentially of organosilane-capped silica. The purified product is dried to provide a dry organosilane-capped silica. The aqueous acid medium can include a displacing reagent which displaces at least one reactive functional group of the di- or tri-functional organosilane. The present invention further provides-continuous methods of treating silica with di- and tri-functional organosilanes, wherein the organic liquid and/or the organosilicon impurities are recycled and reused.

Dependencies are inferred from the claim text.