Solute–solvent and solvent–solvent interactions in binary solvent mixtures. Part 3. The ET(30) polarity of binary mixtures of hydroxylic solvents

Abstract

Solvent exchange models have been applied to the transition energy of the Dimroth–Reichardt E_T(30) solvatochromic indicator in binary hydroxylic solvents at 25 °C. The models tested have been critically evaluated to show the simplifications and limitations inherent to each model. A general five-parameter model [two preferential solvation and three E_T(30) parameters] has been selected as the most appropriate. This model fits well the 51 binary systems tested in this work and 19 different ones previously studied. It also allows a quantitative interpretation of the E_T(30) behaviour of the binary systems in terms of solute–solvent and solvent–solvent interactions.