High pressure phase equilibria of the ternary system 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + carbon dioxide + ferrocene

► The phase behavior of a ternary ionic liquid + supercritical fluid + solid organic compound is experimentally studied. ► The LV → L transition shifts to higher pressures with increasing CO2 concentration. ► The SL → L transition shifts to lower temperatures with increasing CO2 concentration. ► CO2 acts as a co-solvent in all measurements, even at high CO2 concentrations. ► Removing CO2 from the system by pressure release results in precipitation of the ferrocene out of the ionic liquid.