Improved Esmaeilzadeh-Roshanfekr equation of state for ionic liquids

In this study, the densities of 27 pure components of ionic liquids (ILs) are analyzed using the Esmaeilzadeh-Roshanfekr (ER) equation of state and its modified version (mER EoS). The critical properties necessary for EoS calculations, including Tc, Pc, νc, and ω, are determined through the fragment contribution-corresponding states (FC-CS) method based on a dataset comprising 3272 experimental data points originating from 128 diverse ILs. The dataset comprises 1222 measurements within the temperature range of 273.15 to 473.15 K at ambient pressure, with 1682 data points collected at ambient temperature and pressures up to 200 MPa. The modified alpha function parameters (m1, m2) and critical compressibility factor (ζc) in the mER EoS lead to improved density predictions, reflected in a reduced average absolute deviation. Specifically, the mER EoS achieves an average absolute deviation of 4.62 and 5.99