Vapor Pressure Measurement of Ternary {KNO3 + [Emim] Cl + H2O}, {KNO3 + [Emim]Ac + H2O}, {KNO3 + [Emim] NO3 + H2O}, and {KNO3 + [Emim]Br + H2O} Systems

Due to the advantages of high temperature stability, low corrosion, and good heat transfer performance, potassium nitrate aqueous solution holds application potential in absorption systems. In order to further improve its absorption ability, ionic liquids (ILS) such as [Emim]Cl, [Emim]Ac, and [Emim]Br were selected as additives. In this paper, vapor pressures of four {KNO3 + ILS +H2O} ternary systems were measured by a dynamic boiling point method, including {KNO3+ [Emim]Cl + H2O}, {KNO3 + [Emim]Ac +H2O}, {KNO3 + [Emim]NO3 + H2O}, and {KNO3 + [Emim] Br +H2O}. Molar ratios between KNO3 and ILs were 1:1 for these systems, and the total absorbent mass fractions were in the range of 0.20 to 0.70. Experimental data were regressed by Antoine-type equations, and the average absolute relative deviations (AARD%) between the experimental and calculated values were no more than 0.78%, which showed good consistency of these experiments. Vapor-liquid equilibrium behavior of these different ionic liquid ternary systems were compared and [Emim]Ac showed best performance in reducing vapor pressure at relatively higher mass fractions. [GRAPHICS] .