Titrations in non-aqueous media. Part VIII. Basicity order of alkylammonium acetates in the presence of mercury(II) acetate in nitrobenzene-acetic acid mixture

Abstract

Seventeen alkylammonium chlorides (methyl, ethyl, propyl and butyl) and ammonium chloride were converted into the corresponding alkylammonium acetates and ammonium acetate in the presence of a moderate excess of mercury(II) acetate in nitrobenzene-acetic acid (16 + 1 V/V) and then the acetates were titrated potentiometrically with perchloric acid. All the compounds gave good S-shaped titration curves. From these curves, the half-neutralisation potentials of the acetates were determined. The basicity order of the primary, secondary and tertiary alkylammonium acetates is R₃NHOAc > R₂NH₂OAc > RNH₃OAc > NH₄OAc. Irrespective of the size and the shape of the alkyl groups, the half-neutralisation potentials of the primary, secondary and tertiary alkylammonium acetates are approximately 290, 261 and 235 mV, respectively. The graph of alkyl numbers of the acetates versus half-neutralisation potentials, including the half-neutralisation potential of ammonium acetate (314 mV), was nearly a straight line, which may be used in special instances for the differentiation of alkylammonium chlorides.