IONIC SOLVATION IN WATER + COSOLVENT MIXTURES .20. THE NEUTRAL COMPONENT OF FREE-ENERGIES OF TRANSFER OF SINGLE IONS FROM WATER INTO MIXTURES OF WATER + HYDROXYLIC COSOLVENTS

Values for the free energy of transfer of neutral inorganic and organic molecules from water into mixtures of water with a series of hydroxylic co-solvents, ΔGXXXt (i)n have been calculated from the solubilities of gaseous molecules. These are utilised to calculate the free energy of transfer of the charge alone, ΔGXXXtie, for some ions and ΔGXXXtie is compared with the physical properties and ΔGXXXtie values available for large organic cations and anions. By combining the equations of the scaled particle theory with ΔGXXXtin, it is possible to calculate, for low mole fractions of co-solvent, the change in the free energy of interaction of the dissolved molecule with the surrounding solvent arising from the transfer water → mixture, ΔGintti. For inorganic molecules, ΔGintt has small negative values, whilst higher negative values are found for larger organic molecules. © 1990.