Thermodynamics Research Center / ThermoML | Thermochimica Acta

ABSTRACT

In the present work thermochemistry of intermolecular interactions of organic compounds in solu-tions of imidazolium based ionic liquids (ILs) has been studied using solution calorimetry method.Enthalpies of solution at infinite dilution of non-polar (alkanes, aromatic hydrocarbons) and polar(alcohols, amides, and etc.) organic solutes in two ionic liquids 1-butyl-3-methylimidazolium tetrafluo-roborate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate were measured at 298.15 K. Thescale of van der Waals interactions of imidazolium based ILs has been proposed on the basis of solu-tion enthalpies of n-alkanes in their media. The effect of the cation and anion structure of ILs on theenthalpies of solvation was analyzed. Enthalpies of hydrogen bonding of organic solutes with imida-zolium based ILs were determined. It has been shown that these values are close to zero for protonacceptor solutes. At the same time, enthalpies of hydrogen bonding of proton donor solutes with ionicliquids are increased depending the anion: tetrafluoroborate . bis(trifluoromethylsulfonyl)imide less than 2-(2-methoxyethoxy)ethyl sulfate less than trifluoromethanesulfonate. Enthalpies of van der Waals interactions andhydrogen bonding in the solutions of imidazolium based ionic liquids were compared with the same datafor molecular solvents.