Vapor Pressure Measurement of Ternary Systems LiCl + [Emim]I + H2O and LiCl + [Dmim]I + H2O

The vapor pressure properties of ionic liquids (ILs) 1-ethyl-3-methylmidazolium iodide ([Emim]I) and 1,3-dimethylimidazolium iodide ([Dmim]I) as absorbent species in lithium chloride aqueous solution (LiCl/H2O) are experimentally investigated. The vapor pressure data of ternary IL mixtures, LiCl + [Emim]I + H2O (mass ratio LiCl/[Emim]I = 3) from a temperature of 338.26–419.83 K at three mass fractions of the absorbent (0.3, 0.4, and 0.5) and LiCl + [Dmim]I + H2O (mass ratio LiCl/[Dmim]I = 3) from a temperature of 354.54–427.23 K at four mass fractions of the absorbent (0.3, 0.4, 0.5, and 0.54), were measured and reported using the boiling point method. The Antoine-type equation was used to fit the experimental data. The average absolute relative deviation (AARD%) values of the experimental data and the calculation results were 0.416 and 0.515%, respectively. By comparing the measured vapor pressure data with a binary mixture (LiCl + H2O), the ternary system of lithium bromide aqueous solution and the same IL (LiBr + ILs + H2O), and ternary mixtures of lithium chloride and ILs of the same organic cation (LiCl + ILs + H2O), it was found that, under experimental conditions, the order of vapor pressures of the proposed ternary systems is LiCl + [Dmim]I + H2O < LiCl + [Emim]Cl + H2O < LiCl + H2O, LiCl + [Emim]I + H2O < LiBr + [Emim]I + H2O, LiCl + [Dmim]I + H2O < LiBr + [Dmim]I + H2O, LiCl + [Emim]I + H2O < LiCl + [Emim]Cl + H2O < LiCl + [Emim]Br + H2O, and LiCl + [Dmim]I + H2O < LiCl + [Dmim]DMP + H2O < LiCl + [Dmim]Cl + H2O < LiCl + [Dmim]BF4 + H2O.