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

Abstract

The effect of eight potassium salts (KF, K 3 PO 4 , KOCN, K 2 CO 3 , KCl, K 2 SO 4 , KBr and 2 KI) on glycerol carbonate (GC) is studied through NMR, DSC, solubility and ATR-3 FTIR experiments. From the solubility data, the main thermodynamic functions of 4 solution and solvation are estimated, and the mean molal activity coefficients are 5 calculated. The results suggest that the capability of an anion to establish hydrogen 6 bonds with the solvent molecules (or behave as a base, as in the case of fluoride, 7 phosphate, cyanate and carbonate) is the most important structural feature that 8 determines its effects on the solvent structure. On the other hand potassium iodide 9 behaves in an anomalous way, due to the large polarizability of the anion that can 10 form non-electrostatic, van der Waals dispersive intermolecular interactions.

Effect of Hofmeister Ions on Transport Properties of Aqueous Solutions of Sodium Hyaluronate

“…The ions on the left side are called kosmotropes (“water structure makers”), while on the right side are chaotropes (“water structure breakers”) [ 21 ]. It is known that Hofmeister or specific ion effects affect some physicochemical properties of aqueous [ 23 , 24 ] and nonaqueous [ 25 , 26 ] systems. As an example, there are studies made by Mráček et al [ 27 ] about the influence of Hofmeister series ions on HyA behaviour and HyA film-swelling.…”

Specific Ion Solvation and Pairing Effects in Glycerol Carbonate

“…1−8 Several properties that are shared between the cyclic carbonates promote their usefulness in electrolyte solutions, 9,10 namely, their large dipole moments (4.81, 5.26, and 5.05 D for EC, PC, and GC respectively) 11 and dielectric constants (90.5, 66.6, and 111.5). 12,13 By these criteria, GC appears to show potential as a solvent for inorganic salts in energy storage systems. GC also displays the largest liquid phase temperature range of the cyclic carbonates, with a melting point of −39 °C, a boiling point of 115 °C, and a flash point of 190 °C.…”

“…This stands in contrast to the other cyclic carbonates which exhibit long-range solvent chain formation and in the case of EC long-range bidirectional stacking. 13,14 The strong hydrogen bonding that is present in the pure GC solution has a large impact on its solvation behavior when electrolytes are introduced. In our efforts to investigate the origin of the solvation behavior seen by the Lo Nostro group 13,14 when KF is the electrolyte in a GC system, we found that the strong binding between the anion and the hydroxyl of GC leads to the formation of a uniquely organized shared-solvent ion pair.…”

“…13,14 The strong hydrogen bonding that is present in the pure GC solution has a large impact on its solvation behavior when electrolytes are introduced. In our efforts to investigate the origin of the solvation behavior seen by the Lo Nostro group 13,14 when KF is the electrolyte in a GC system, we found that the strong binding between the anion and the hydroxyl of GC leads to the formation of a uniquely organized shared-solvent ion pair. The ions, when paired in this manner, exert a strong structuring effect on the GC molecules that surround the fluoride ion.…”

“…In our previous work, we postulated that the identity of the anion was responsible for the shifts in ion-pairing behavior, which in turn influences the increase in the glass transition temperature. 13,14 Other previous works have examined the correlations between ion size and electronegativity or chemical hardness. 16−19 Here, we compare the interactions of KF and KCl as ion pairs and isolated ions.…”