The comparative analysis of solvation thermochemistry of organic non-electrolytes in ionic liquids and molecular solvents

Abstract

The present review is devoted to the critical analysis of literature and own data on the solution and solvation enthalpies of nonelectrolytes in ionic liquids. The analysis is based on the concept of the relationship between the structure of the solute molecules and the intermolecular solute–solvent interactions. It was shown that the contribution of the solvophobic effect to the solvation enthalpy of nonelectrolytes in ionic liquid is insignificant. Despite the ion–dipole solvent–solvent interactions in the ionic liquids, the contribution of polar solute–solvent interactions to the solvation enthalpy of is also negligible. Based on data on the solvation enthalpies of aromatic and heteroaromatic derivatives in ionic liquids, an additive scheme for calculating the corresponding solvation enthalpies is proposed. Previously developed approaches to dividing the solvation enthalpy into the contributions from the nonspecific solvation and specific interactions have been applied to ionic liquids. The enthalpies of the solute–solvent hydrogen bonding were determined.In each of the cases considered above, a comparison with the data on the solvation enthalpies of the same non-electrolytes in benzene and N,N-dimethylformamide was made in order to determine the relation of ionic liquids to common solvents. It was shown that the structure effects of dissolved nonelectrolyte molecules on their solvation enthalpy in ionic liquids do not differ significantly from the ordinary solvents.