Ionic solvation in water–Co-solvent mixtures. Part 18.—Free energies of transfer of single ions from water into water–2-methoxyethanol mixtures

Abstract

ΔG^°_t(H⁺), the free energy of transfer of the proton from water into water–co-solvent mixutres, has been determined experimentally for the co-solvent 2-methoxyethanol keeping the conditions water-rich. Specific criticisms of the method used are discussed and rejected . ΔG^°_t(X^–) for simple anions has been calculated from ΔG^°_t(HX) leading to the calculation of ΔG^°_t(M⁺) from ΔG^°_t(MX). ΔG^°_t(i)_e, the free energy of transfer of the charge alone, has been determined for organic cations and anions using ΔG^°_t(H⁺) found here, combined with values for the pK of acids and bases in water–2-methoxyethanol. ΔG^int_t, the difference in the partial molar free energy of interaction of a molecule with the solvent in transferring the molecule from water into the mixture has been determined for two electrically neutral organic bases. The values for ΔG^°_t(i), ΔG^°_t(i)_e and ΔG^int_t(i) are compared among themselves and with values found in mixtures of water with other co-solvents.