Modeling Solubility Behavior of CO2 in [C2-mim][BF4] and [C4-mim][BF4] Ionic Liquids by sPC-SAFT Equation of State

The simplified perturbed chain statistical associating fluid theory (sPC-SAFT) Equation of State (EOS) was proposed to describe the thermodynamic properties of pure ionic liquids (ILs). A set of sPC-SAFT parameters for 2 ILs was obtained by fitting the experimental liquid densities data over a wide range of temperature at atmospheric pressure. Good agreement with experimental density data was observed at both atmospheric and high pressure when ILs were considered as an association compound with various association schemes or a non association compound .Then, the solubility of CO2 in 1-alkyl-3-methylimidazolium tetrafluoroborate ILs was studied over a wide range of temperatures and pressures. For such binary systems, the binary interaction parameter was used by fitting to experimental vapor-liquid equilibrium data. This parameter is temperature-dependent and has linear correlation with temperature. In all cases, good agreement between sPC-PSAFT correlation and experimental data for these binary mixtures was observed.