Correlation of supercritical CO2-ionic liquid vapor-liquid equilibria with the e*-modified Sanchez-Lacombe equation of state

The e*-modified SanchezLacombe equation of state (e*-modified SL EOS) contains a temperature-dependent interaction energy that allows it to provide better pure component ionic liquid pressurevolumetemperature representation than the original SL EOS. In this work, we applied the e*-modified SL EOS to correlate available high pressure CO2ionic liquid vaporliquid equilibrium (VLE) data, which are important for developing viscosity correlations. Usual SL EOS mixing rules were applied with one interaction parameter, kij, which was fitted to the data. For the case of kij equal to zero, the e*-modified SL EOS could greatly improve the average relative deviation (ARD) of the VLE (ARD 14.6%) over that of the original SL EOS (ARD 44.0%). For the case of kij being fitted for both EOS, representation of the VLE of both equations was similar (ARD?=?9%). The e*-modified SL EOS is able to describe the vaporliquid equilibria data over a wide range of pressures (0.1?<?P?<?100?MPa) and gives semi-quantitative (ARD?<?15%) representation of CO2 solubilities in many ionic liquids from knowledge of only the pure component properties. (c) 2012 Curtin University of Technology and John Wiley & Sons, Ltd.