Dissociation constants and preferential solvation in some 2-methylpropan-2-ol–alcohol mixtures

Abstract

An equation relating dissociation pK values of electrolytes in binary solvent mixtures of low relative permittivity has been derived. The equation takes into account preferential solvation of the electrolyte by one of the solvents of the mixture and allows quantification of this effect. The equation is successfully applied to dissociation of picric acid, tetrabutylammonium picrate, bromide and hydroxide, and tetramethylammonium hydroxide in some 2-methylpropan-2-ol–alcohol mixtures and it describes very well the dissociation of the electrolytes in the range of solvent compositions studied (2-methylpropan-2-ol-rich mixtures).