ADSORPTION OF 1-BUTANOL FROM WATER ON MODIFIED SILICATE SURFACES

The structure and the sorption properties of partially hydrophobized s ilicates (dodecylammonium and dodecyldiammonium vermiculites) have bee n investigated in aqueous solutions of 1-butanol. The alcohol is prefe rentially adsorbed on the surface. The interlayer composition is calcu lated from adsorption and x-ray diffraction data. In air-dried state t he organic cations lie flat on the interlamellar surface. In aqueous b utanol solutions, the basal spacing of dodecylammonium vermiculite gra dually increases with the extent of butanol adsorption because the cha ins increasingly point away from the surface. The basal spacing of dod ecyldiammonium vermiculite is virtually independent on the interlayer composition because the expansion of the interlayer space is stericall y restricted and a relatively rigid structure is formed. The enthalpy of the displacement of water by 1-butanol has been determined by flow sorption microcalorimetry. The displacement process is endothermic.