Solubility measurement and prediction of carbon dioxide in ionic liquids

Room temperature ionic liquids are receiving growing attentions as green solvents for reactions and separations. In particular, ionic liquids+carbon dioxide systems are of importance in the recovery of solutes in supercritical fluid extraction. Solubilities of carbon dioxide in ionic liquids, [bmim][PF6], [C6mim][PF6], [emim][BF4], [C6mim][BF4], [emim][Tf2N] and [C6mim][Tf2N], were experimentally studied at 298.15K and up to 1MPa in the present study. Present and literature data were fitted to determine group segment numbers and interaction energy parameters between groups for the group contribution non-random lattice–fluid equation of state. The agreements between data and calculated solubilities and densities were found generally good for ionic liquids with 1-alkyl-3-methylimidazolium cations and [PF6], [BF4] and [Tf2N] anions.