Effect of ionic liquids on the isobaric vapor-liquid equilibrium behavior of dichloromethane + methanol at 101.3 kPa

Isobaric vapor-liquid equilibrium data for the ternary systems of dichloromethane (DCM) + methanol + ionic liquids (ILs) were measured at a constant pressure of 101.3 kPa using a modified Othmer and they were also amended and correlated using the NRTL equation and the results corresponded closely to the original data. The ILs used were 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Hmim][NTf2]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim][NTf2]). The results indicated that the addition of ILs had an outstanding effect on the azeotropic system and [Bmim][BF4] and [Hmim][NTf2] could remove the azeotropic point with the mole fraction of 0.109 and 0.162, respectively, which means they could break the azeotropic phenomenon of DCM + methanol. The influence of concentration and kind of ILs was also discussed in this work.