Solvation of ions. XXIV. Entropies of transfer of some divalent metal ions from water to nonaqueous solvents

Standard free energies (molar scale) for the transfer of Cd2+, Zn2+, and Ba2+ from water to methanol, hexamethylphosphoramide, acetonitrile, dimethylformamide, and dimethyl sulfoxide have been obtained by means of extrathermodynamic assumptions. Corresponding standard entropies of transfer have also been obtained using enthalpies of transfer from an earlier paper. There is a much larger decrease of entropy when divalent rather than monovalent cations are transferred from water to these nonaqueous solvents. Results are discussed in terms of current models of ion solvation. Divalent cations have more than one layer of solvent molecules in their solvation shells in most of the solvents studied. HMPT has par- ticularly strong enthalpic and entropic interactions with cations

Interaction Between Some Monosaccharides and Aspartic Acid in Dilute Aqueous Solutions

Interaction between aspartic acid and d-glucose, d-galactose, and d-fructose has been studied by isothermal titration calorimetry, calorimetry of dissolution, and densimetry. It has been found that d-glucose and d-fructose form thermodynamically stable associates with aspartic acid, in contrast to d-galactose. The selectivity in the interaction of aspartic acid with monosaccharides is affected by their stereochemical structures