Ionic solvation in water + Co-solvent mixtures. Part 2.—Free energies of transfer of single ions from water into mixtures of water with acetone, isopropanol, glycerol or methanol

Abstract

The method used previously to calculate the free energy of transfer ΔG°_t of the solvated proton from water into methanol + water mixtures is applied to mixtures of water with acetone, isopropanol or glycerol. ΔG°_t(HCl) for these mixtures has been calculated from values for the standard electrode potentials for appropriate cells, and ΔG°_t(Cl^–) obtained using the values for ΔG°_t(H⁺). ΔG°_t for some silver salts into acetone + water are calculated from solubility products. These ΔG°_t and other published ΔG°_t(MX) for acetone + water and methanol + water are separated into ΔG°_t(M⁺) and ΔG°_t(X^–). Values for the ionic product of water in methanol + water are used to calculate ΔG°_t(OH^–), and values for ΔG°_t(NH₄⁺)–ΔG°_t(NH₃) in methanol + water are also calculated. These ΔG°_t values are compared with previous values in methanol + water and the differences between solvent mixtures discussed in terms of solvent structure and ionic solvation.