Effect of cation on the solubility of carbon dioxide in three bis(fluorosulfonyl)imide low viscosity ([FSI]) ionic liquids

The solubility of carbon dioxide in three bis(fluorosulfonyl)imide-based ionic liquids: N-propyl-n-methyl-piperidinium bis(fluorosulfonyl)imide ([p(3)mpip][FSI]), N-propyl-n-methyl-pyrrolidinium bis(fluorosulfonyl)imide ([p(3)mpyrr][FSI]) and N-propyl-n-methyl-n,n-dimethyl-ammonium bis(fluorosulfonyl)imide ([N4441][FSI]) was measured at (298.15, 313.15, and 343.15) K and pressure up to about 2 MPa. The Henryʹs law constants for CO2 in the three ILs, ([p(3)mpip][FSI], [p(3)mpyrr][FSI] and [N4441][FSI]) at 298 K are (4.1, 4.0, and 3.8) MPa respectively, indicating the negligible effect of change of cation precursors on CO2 solubility. Solubility of CO2 in the present ILs with [FSI] anion is comparable with those in the ILs containing a more fluorinated common anion, [Tf2N]. The solubility data were correlated well with the Soave–Redlich–Kwong equation of state (SRK-EoS).