Investigation of the Effect of Alkyl Chain Length and Anion Type on the Thermo Physical Properties of the Ionic Liquids Using Two Versions of the SAFT Equation of State

In this study, the pressure-volume behavior and some of the second-order thermophysical properties such as heat capacity and speed of sound for a family of imidazolium-based ionic liquids using the SAFT Equation of States (EoSs) were calculated and the effect of alkyl chain length and anion type on these properties were investigated. Two version of SAFT EoSs were used for calculation of thermophysical properties of ionic liquids: 1. PC-SAFT 2. Heterosegmented SAFT, both of them have very good ability for the prediction of the Helmholtz free energy and first-order thermophysical properties such as pressure-volume behavior. But in the prediction of second order thermophysical properties such as heat capacity at constant volume, heat capacity at constant pressure and speed of sound, have not accurate and performance. Also, the equations do not show the process of change in alkyl chain length and anion type on the second order thermophysical properties well.