study of physical absorption of carbon dioxide in imidazolium-based ionic liquids

in this study, the solubility of co₂ in imidazolium-based ionic liquids with different anions has been compared at 323.15 k in mole fraction and molality scals. the anions considered in this study are [pf₆]^–, [otf]^–, [bf4]^–, [tf₂n]^–. results show that solubility of co₂, expressed in mole fraction scale, in the following sequence: [c₈mim][tf₂n] > [c₄mim][otf] > [c₈mim][pf₆] > [c₂mim][otf] > [hc₂mim][bf4] [c₂mim][bf₄]. when the concentration is switched to molality scale, the solubility of co₂ in the ionic liquids in the following sequence: [c₈mim][tf₂n] ≈ [c₈mim][ pf₆] > [c₄mim][otf] > [c₂mim][otf] > [c₂mim][bf₄] > [hc₂mim][bf₄]. the experimental data at 323.15 k were correlated by using the pitzer’s model. the pitzer’s model has a good predict for ionic liquids + carbon dioxide systems in this work.