An Improved ISM Equation of State for Polar Fluids

We developed an equation of state (EOS) by Ihm, Song, and Mason (ISM) for polar fluids. The model consists of four parameters, namely, the second virial coefficient, an effective van der Waals co-volume, a scaling factor, and the reduced dipole moment. The second virial coefficient is calculated from a correlation that uses the heat of vaporization, and the liquid density at the normal boiling point. The reduced dipole moment is calculated from experimental dipole moments data and other parameters were obtained by regressing against saturated liquid density data. In this work, we generalized this equation to calculate the saturated liquid density of n-alkanol, water, and ammonia. The calculated results are also compared with SAFT equation of state and show that the saturated liquid density can be predicted within about 1.2%.