Ionic solvation in water + co-solvent mixtures: Part 24. Free energies of transfer of single ions from water into water + 1,2-dimethoxyethane mixtures

Abstract

The spectrophotometric solvent-sorting method for determining the free energy of transfer of the proton from water into water + co-solvent mixtures Δ G t ⊖(H +) has been shown to apply to water-rich mixtures containing, 1,2-dimethoxyethane. Using Δ G t ⊖H +), values for Δ G t ⊖(anion) and Δ G t ⊖(cation) can be derived from the free energies of transfer of acids and salts. The free energy of transfer of the charge alone on large organic ions, Δ G t ⊖(i) e, has been calculated using p K a, values for organic acids in water and in the mixture in conjunction with Δ G t ⊖(H +) values. These values for Δ G t ⊖(i) and Δ G t ⊖(i) e in water + 1,2-dimethoxyethane mixtures are compared with similar free energies of transfer for ions from water into mixtures of similar co-solvents with water. To aid this comparison, values for the relative partial molar volumes of water and 2-methoxyethanol have been calculated for their mixtures.