Imidazolium-Based Ionic Liquids Containing the Trifluoroacetate Anion: Thermodynamic Study

New experimental vapor pressures and vaporization enthalpies of the ionic liquids \( {\text{C}}_{2} {\text{mim]CF}}_{3} {\text{CO}}_{2} ] \) and \( {\text{C}}_{4} {\text{mim]CF}}_{3} {\text{CO}}_{2} ] \) have been measured by the QCM method. The solution enthalpies of these ionic liquids were measured by using high-precision solution calorimetry and were used for calculation the aqueous enthalpy of formation \( \Delta_{\text{f}} H_{\text{m}}^{ \circ } ({\text{CF}}_{ 3} {\text{CO}}_{2}^{ - } ,_{{}} {\text{aq}}) \) of the anion for combination with quantum-chemical results. The solubility parameters of the ILs under study have been derived from experimental \( \Delta_{\text{l}}^{\text{g}} H_{\text{m}}^{ \circ } \)(298.15 K) values and were used for estimation of miscibility of some common solutes with \( {\text{C}}_{n} {\text{mim]CF}}_{3} {\text{CO}}_{2} ] \).