Solvent extraction of mineral acids. IV. Solute‐solvent interaction in the system perchloric acid‐water‐tri‐N‐butyl phosphate

Abstract

AbstractThe distribution of perchloric acid between water and pure tributyl phosphate (TBP) was examined as a function of increasing acid concentration in the initial aqueous solution. The solvent extracts were investigated by determinations of increase in volume and measurements of viscosity, density and conductivity. The water content of the tributyl phosphate layers has also been determined. The data conform with the assumption of several consecutive interactions between mineral acids and the highly basic tributyl phosphate extractant. A discussion of the nature of the species existing in, or extracted into, the tributyl phosphate phase is given and it is suggested that there are four main species involved: [(TBP)4,HClO4,(H2O)8]; [(TBP)2,HClO4,(H2O)5]; [(TBP)4,(HClO4)3,(H2O)10] and [TBP,HClO4,(H2O)2·5]. The mechanism of multistage extraction is suggested.