Average intermolecular interaction in ionic liquids and a new equation of state

In this work an equation of state was presented for ionic liquids that can be derived using the average intermolecular potential (6, 3). This equation of state predicts the linear behavior of (Z − 1)υ2 versus ρ. It was shown that two types of temperature dependency relations for the equation of state parameters are applicable. The superiority of the temperature dependency relations for the proposed equation of state parameters respect to the corresponding relations for Farzi et al. and Tait equations of state parameters was investigated. The density, the isothermal compressibility, and the isobaric expansivity of ionic liquids were calculated using the presented equation of state. The percentage of the average absolute relative deviation for density prediction was 0.05% and for the isothermal compressibility and the isobaric expansivity was in the limit of the reported values in literatures.