Abstract
Organic cations were substituted for some of alkali cations on the surface of metaphosphates by immersion in aqueous solutions of hydrochlorides of ethylamine, hexamethylenediamine and aniline. The heats of immersion of the surface-treated phosphates in benzene and methanol were measured with a twin microcalorimeter, and the following results were obtained.
(1) When the phosphates were treated with ethylamine, little change of their surface properties was observed.
(2) The specific surface area of surface-treated phosphate increased with the amount of organic cation substituted.
(3) The heat of immersion of the phosphates treated with hexamethylenediamine increased, especially in benzene, with increasing surface concentration of the organic cation.
(4) In benzene the heat of immersion of the phosphates treated with aniline decreased with increasing surface concentration of the anilinium cation, while the immersional heat in methanol increased with the concentration. This dependence in methanol can be interpreted in terms of the OH-π interaction between the anilinium cations on the surface of the phosphate and the methanol molecules.
