Ionic solvation in water–cosolvent mixtures. Part 14.—Free energies of transfer of single ions from water into water–ethylene carbonate and water–propylene carbonate mixtures

Abstract

The spectrophotometric solvent-sorting method for determining the free energies of transfer for individual ions, ΔG^°_t(i), from water into a mixture of water and cosolvent has now been applied to cosolvents which increase the dielectric constant and enhance the solvent structure when added in small concentrations to water. The spread of ΔG^°_t(i) values found, viz.ΔG^°_t(i) for i= a cation is negative and ΔG^°_t(i) for i= an anion is positive, is similar to those found in mixtures where the cosolvent decreases the dielectric constant and enhances the solvent structure or increases the dielectric constant and decreases the solvent structure. Values for ΔG^°_t(i)_e, the free energy of transfer of the charge alone, are found for some large organic anions.