Ionic solvation in water–cosolvent mixtures. Part 12.—Free energies of transfer of single ions from water into water–propan-1-ol mixtures

Abstract

The spectrophotometric solvent-sorting method for determining the free energy of transfer of the solvated proton, ΔG^°_t(H⁺), between water and mixtures of water–cosolvent has been applied to mixtures of water with propan-1-ol. The assumptions underlying the method are examined critically and the consequences of varying the standard states of the species involved in the solvent sorting in the mixture are explored. The resulting values for ΔG^°_t(H⁺) are used to determine ΔG^°_t(X^–) from ΔG^°_t(HX) and these values for ΔG^°_t(X^–) are used to determine ΔG^°_t(M⁺) for other cations from ΔG^°_t(MX). The variation of ΔG^°_t(i) for individual ions in water–propan-1-ol are compared with the variation of ΔG^°_t(i) in mixtures of water with other cosolvents. Values for ΔG^°_t(Ag⁺) and ΔG°(CNS^–) are determined for other water–cosolvent mixtures.