Modeling solubilities of gases in the ionic liquid 1-ethyl-3- methylimidazolium tris(pentafluoroethyl)trifluorophosphate using the Peng-Robinson equation of state

In this paper, vapor-liquid equilibrium (VLE) data of binary mixtures containing gases such as carbon dioxide (CO₂), methane, ethane, propane, or butane in the ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]) have been modeled using the Peng-Robinson equation of state (PR-EoS), combined with quadratic mixing rules. The calculations were performed at various temperatures. All calculations were performed with only one adjustable binary interaction parameter except in the system with CO₂. In that case, two adjustable binary interaction parameters were used. The results showed a temperature dependence of the adjustable parameters. In all cases, the calculated results have been found to be in good agreement with the experimental data. A total absolute average deviation in the bubble-point pressures of less than 3% was established over a wide temperature range (293-363 K) and pressures up to 11 MPa.