Prediction of CO2 solubility in ionic liquids with QM and UNIQUAC models

Abstract

In recent years, ionic liquids shows their abilities in many processes, like enzymatic reactions, electrochemical applications, catalysis processes, or separation processes. In this work, CO2 solubility in Ionic liquids has been calculated based on two thermodynamic models, i.e., the UNIQUAC model and the quantum model, based on COSMO-RS theory of interacting molecular surface charge. To investigate the accuracy of the considered models the predicted solubility of CO2 in ionic liquids was compared with experimental data in a wide range of pressure and temperature. The ionic liquids [bmim][Bf4], [bmim][Tf2N], [emim][Tf2N], [Omim][Pf6], [Omim][Tf2N], [emim][Bf4] and [Hmim][Tf2N] were used here to investigate the capability of the models in predicting CO2 solubility. It was found that the accuracy of COSMO-RS is good, but only for some ILs, whereas UNIQUAC is the most capable method in predicting the gas solubility.