Specific ion effects in non-aqueous solvents: The case of glycerol carbonate

The effect of eight potassium salts (KF, K₃PO₄, KOCN, K₂CO₃, KCl, K₂SO₄, KBr and KI) on glycerol carbonate (GC) is studied through NMR, DSC, solubility and ATR-FTIR experiments. From the solubility data, the main thermodynamic functions of solution and solvation are estimated, and the mean molal activity coefficients are calculated. The results suggest that the capability of an anion to establish hydrogen bonds with the solvent molecules (or behave as a base, as in the case of fluoride, phosphate, cyanate and carbonate) is the most important structural feature that determines its effects on the solvent structure. On the other hand potassium iodide behaves in an anomalous way, due to the large polarizability of the anion that can form non-electrostatic, van der Waals dispersive intermolecular interactions.