Modification of Tao-Mason equation of state to ionic liquids

作者：Yousefi Fakhri^*; Karimi Hajir

来源：Ionics, 2012, 18(1-2): 135-142.

DOI：10.1007/s11581-011-0605-8

• Ionic liquids
• Density
• Equation of state
• Tao-Mason EOS
• Modeling

In our previous paper, we extended the Tao and Mason equation of state (TM EOS) to refrigerant fluids, using the speed of sound data. Here, we predict the equation of state for ionic liquids (ILs). The considered ILs are[Bmim][PF6], [C(2)mim][NtF(2)], [C(3)mim][NtF(2)], [C(6)mim][NtF(2)], [C(7)mim][NtF(2)], [C(2)mim][EtOSO3], [Bmim][MeSO4], [Bmim][OcSO(4)], and [C(4)mim][dca]. The equation of state consists of three temperature-dependent parameters: the second virial coefficient, a constant for scaling the softness of repulsive force, and an effective hard-sphere diameter equivalent to the van der Waals co-volume. The second virial coefficients of ILs are scare and there is no accurate potential energy function to allow their theoretical calculation. In this work, the second virial coefficient have been calculated using corresponding states correlation based on temperature and density at normal boiling point. The other two parameters of the equation of state can be calculated using a scaling rule. Analysis of our predicted results shows that the Tao-Mason equation of state is capable of accurately predicting the density of ILs at any temperature and pressure. The overall average absolute deviation densities for 1,633 data points are 2.05%. Also, the density of ILs obtained from the TM EOS has been compared with those calculated from vdW-CS-beta and Peng-Robinson (PR) equation of state. Our results are in favor of the preference of the TM EOS over the two other equations of state. The overall average absolute deviation for 1,633 data points calculated by vdW-CS-beta and PR equation of state are 6.63% and 12.19%, respectively.

• 出版日期2012-1