LAUSR

Abstract In this work, the solubilities of carbon dioxide in eight imidazolium based ionic liquids (1-ethyl-3-methyl imidazolium tetrafluoroborate [emim][BF4], 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [emim][Tf2N], 1-n-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4], 1-n-butyl-3-methyl imidazolium hexafluorophosphate [bmim][PF6], 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulf-onyl) imide [bmim][Tf2N], 1-n-octyl-3-methylimidazolium tetrafluoro borate [omim][BF4], 1-n-octyl-3-methylimidazolium hexafluorophosphate [omim][PF6], 1-n-octyle-3-methylimidazolium bis (trifluoro methylsulfonyl) imide [omim][Tf2N]) at different temperatures and pressures were obtained by using modified scaled particle theory (SPT), and the results were compared with the experimental values reported in the literature. In the SPT, the calculations of the solubility are related to the parameters and the physical properties of the solute and the ionic liquid, which all of them are temperature dependent. In this study, the effect of temperature on the molar volume of ionic liquid, the polarizability of carbon dioxide, the hard sphere diameter of ions and the hard sphere diameter of carbon dioxide have been considered in the calculations of carbon dioxide solubility in ionic liquids. By considering the effect of temperature on the mentioned parameters, the results are in better agreement with the experimental solubilities. In addition, the predicted results by the original and the modified SPT have been compared with those by the UNIFAC-Lei model. The total absolute average relative deviations (% AARD) for all systems were found to be 2.49%, 8.45% and 14.6% for the modified SPT, the original SPT and the UNIFAC-Lei model, respectively. Furthermore, the performance of various mixing rules have been elucidated in the SPT calculations for the estimation of carbon dioxide solubility in different ionic liquids.