Solvation of Anions in Solvent Mixtures as Deduced from the Rates of the Finkelstein Reaction

Abstract The Finkelstein reaction has been studied in five dipolar aprotic–dipolar aprotic solvent mixtures and one protic-dipolar aprotic solvent mixture. The theoretical equations for the rate constant as a function of solvent composition derived previously have been reformulated in terms of the solvent exchange model on the solvation site, taking into account the two main features of solvation: the number of the solvation sites on the solvent molecule and the equilibrium constant for the solvent exchange process. The results obtained previously, together with present results, are comprehensively discussed and the solvent mixtures are classified into four groups from the viewpoint of solute-solvent interaction in the region near the ion, using derived theoretical equations.