Modeling the Solubility of Carbon Dioxide in Imidazolium-Based Ionic Liquids with the PC-SAFT Equation of State

The goal of this work was to check the ability of the PC-SAFT equation to represent the solubility of carbon dioxide (CO2) in ionic liquids. Parameters of pure imidazolium-based ionic liquids were estimated using experimental densities over a large range of temperatures and then correlated with respect to the molecular weight and structure of the solvents. It was found that such a correlation is able to predict the density with high accuracy. The solubility of carbon dioxide in such ionic liquids was then studied. The binary interaction parameter k(ij) needed for the representation of such binary systems was first fitted to experimental liquid-vapor equilibria data. In a second step, a correlation based on the group contribution concept was developed to determine this temperature-dependent parameter. The ability of the model to describe accurately carbon dioxide solubility in imidazolium-based ionic liquids is demonstrated.