Interactions of Hydrophobic Layer Silicates with Alcohol‐Benzene Mixtures II. Structure and Composition of the Adsorption Layer

Abstract

AbstractAdsorption of methanol and benzene on alkylammonium montmorillonite, a hydrophobic layer silicate, changes the orientation of the alkylatnmonium ions at the internal and external surfaces. The hydrophobic chains are pushed off from the surface and assume upright orientations. The methanol molecules are adsorbed preferentially on the silicate surface not covered by alkyl chains, the benzene molecules “solvate” the alkyl chains.—The volume of the adsorbed phase as calculated from the adsorption excess isotherms is smaller than the total interlayer volume occupied by the methanol and benzene molecules. Thus, only a fraction of the liquid between the silicate surfaces is subdued to the adsorption forces. The remaining liquid is considered bulk‐like. The uptake of the bulk‐like liquid in addition to the adsorption phase is apparantly imperative for the process of swelling.