Preparation of the Organophilic Silica Gels by the Surface-Treatment through the Solutions of Various kinds of Alcohols in Hydrocarbon, and their Physicochemical Properties

Abstract

The surface of silica gels was treated by the following procedure; the silica gels were soaked into hexane solution of various kinds of alcohols, i. c. saturated and unsaturated, both of linear and branched chains, phenyl alcohols, etc. Several diols were made to be reacted upon by the respective alcohols in autoclave under high pressure and temperature, and then the solution vapours were blown out at or near the critical point of hexane. The silica gels were then washed by alcohol or benzene and hexane.The following results were confirmed.(1) These surface-treated silica gels were organophilic, except those which were treated by diol in the test of the preferable property of dispersion into the mixed media like water∼hexane.(2) The surface group of treated silica gels were assigned as the alcohoxy group through the elemental analysis and argon surface area and also the silica gel treated by the unsaturated alcohol still held the double bond in the surface group.(3) The silica gel showed the hydrophilicity after treatment with diol, since a hydroxyl group of diols are reacted upon by a silanol of the silica gel.(4) Silanols of the silica gel were not reacted upon by tertiary alcohols like tert-butanol or tert-pentanol.(5) The decrease of argon surface area after surface treatment was interpreted by the existence of the micropores covered by the surface group.