Volumetric properties of ionic liquids and their binary mixtures from improved Tao-Mason equation of state

In this work, the Tao-Mason (TM) equation of state (EOS) has been employed to model the pressure-volume-temperature (PVT) properties of ionic liquids (ILs) by the help of an alternative corresponding state correlation based on the measurable scaling constants, i.e., surface tension and liquid density both at room temperature. Performance of model has been assessed against 2207 experimental data points over a wide temperature range within 293-472 K and pressure range from ambient up to 200 MPa for 17 imidazolium-based ILs. The average absolute deviation (AAD in %) of the calculated densities from literature values was found to be 0.79%. Generally, this work shows that TM EOS based on the surface tension property of ILs outperforms the previous version of TM EOS which uses normal boiling point properties, i.e. the heat of vaporization and liquid density. Improved TM EOS has also been extended to binary systems formed by ionic liquids to predict their volumetric properties. The performance of the mixture version of improved TM EOS has been assessed against 385 experimental data points, and AAD was found to be 0.78%.