Propane/propylene separation and CO₂ capture in magnetic ionic liquid [bmim][FeCl₄]

Magnetic ionic liquids (MILs), combines the general properties of ionic liquid with magnetic properties, are starting to attract interest in the field of propane/propylene separation and CO₂ capture. Solubility data of propane, propylene, cyclopropane and CO₂ in magnetic ionic liquid 1-butyl-3-methylimidazolium tetrachloroferrate [bmim][FeCl₄] at temperatures of (303, 313, 323, 333, 343) K and pressures up to 3300 kPa were determined in the present work. The relative expanded uncertainty of solubility measurement is estimated to be less than 4% with a level of confidence of 95%. The Henry's constants for the four gases in [bmim][FeCl₄] and selectivity of C₃H₆/C₃H₈ in [bmim][FeCl₄] were calculated. And the thermodynamic properties of solvation concerned about the Gibbs energy (Δ_solG^∞), the enthalpy (Δ_solH^∞) and the entropy (Δ_solS^∞) of solvation were also obtained to offer knowledge for understanding the progress of gases dissolved in [bmim][FeCl₄]. The experimental results were correlated with a modified KK equation and NRTL equation.