Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Three novel ether-functionalized ionic liquids (ILs) 1-ethyl-3-(2-methoxyethyl)-imidazolium acetate, [C22O1IM][OAc], 1-ethyl-3-(2-methoxyethyl)-imidazolium thiocyanate, [C22O1IM][SCN], 1-ethyl-3-(2- methoxyethyl)-imidazolium trifluoromethanesulfonate, [C22O1IM][TfO], and two ILs 1-ethyl-3-(2-meth oxyethyl)-imidazolium dicyanamide, [C22O1IM][DCA], 1-ethyl-3-(2-methoxyethyl)-imidazolium bis(tri fluoromethylsulfonyl)imide, [C22O1IM][NTF2] were prepared and characterized. Their density and surface tension were measured at T = (298.15 338.15) K. As a new theoretical model, the ionic molar surface Gibbs free energy, gi, was put forward. The ionic molar surface Gibbs free energy, g , for [BF4] , which was as reference ion, was obtained in terms of the extrathermodynamic assumptions so that the ionic molar surface Gibbs free energy, g+, of the corresponding cations, [Cnmim]+ (n = 2 6), were determined. In terms of the g+ values of [Cnmim]+ (n = 2 6), the g values of 12 kinds of anions were determined and then the average g+ value of [C22O1IM]+ (9.52 +- 0.21 kJ mol 1) was gotten. By using the values of these gi, the predicted values of molar surface Gibbs free energy, gest, and surface tension, cest, for [C22O1IM][X] (X = OAC, SCN, DCA, TfO, NTF2) and other 45 ionic liquids were estimated. In comparison, the predicted values correlated quite well with their matching experimental values.