Vaporization enthalpies of ILs were derived by direct methods (quartz crystal microbalance and thermogravimetry), and indirect methods (combustion, reaction, and solution calorimetry combined with the quantum chemical calculations). Three independent procedures were suggested for the adjustment of vaporization enthalpies to the 298 K. Obtained consistent experimental data was used for evaluation of structure-property relations in ILs. It was established that ILs generally obey group additivity rules. A group-contribution method was developed for prediction of vaporization enthalpies of ILs.
