The development of van der Waals equation of state for ionic liquids

The main purpose of this paper is to develop van der Waals equation of state for calculating the PpT properties of some ionic liquids. This equation of state is based on the generic van der Waals equation of state in which the parameters of this equation of state are dependent of density and temperature. In order to improve the predictive power of the mentioned equation of state for calculation of density of ionic liquids, modifications on the parameters of this equation of state have been considered. The ionic liquids under consideration in this work include the cation: imidazolium and anions: tetrafluoroborate, thiocyanate, trifluoromethanesulfonate, ethylsulfate, bis (trifluoromethylsulfonyl) imide and hexafluorophosphate. The densities of these compounds were calculated from the modified equation of state at different temperatures and pressures. We will see that the comparison of predicted densities from the modified equation of state and experimental data shows high ability of this equation in predicting P rho Tproperties of ionic liquids. The overall average absolute deviation percent of the calculated density of 15 ionic liquids obtained by this equation of state is 0.09%. (C) 2014 Elsevier B.V. All rights reserved.