The gibbs energies of transfer of glycine and glycinate ion from water into water-dimethyl sulfoxide mixtures

Abstract

The Gibbs energies of transfer of glycine from water into water-dimethyl sulfoxide mixtures were determined at 298 K by measurements of substance distribution between immiscible phases. The enthalpy and entropy contributions to ΔG° of glycinate ion resolvation in water-dimethyl sulfoxide solvents were analyzed. The destabilization of glycinate ion was found to be largely determined by the energy component mainly. There was a correlation between the enthalpies of transfer of glycinate ion and the autoprotolysis constants of water-dimethyl sulfoxide solvents. The suggestion was made that changes in the Gibbs energies of glycinate ion resolvation in water-dimethyl sulfoxide and water-alcohol mixtures were largely determined by changes in the acid-base properties of the solvents.