Ammonium-Based Ionic Liquid as an Entrainer for the Separation of n-Propanol + Water and Isopropanol + Water Mixtures

The effect of the ionic liquid tetramethylammonium chloride [TMACl] on the vapor-liquid equilibrium of n-propanol + water and isopropanol + water was studied experimentally. The ionic liquid [TMACl] was identified as a suitable entrainer for breaking the azeotrope of these two alcohol-water mixtures. This work reports the influence of an ammonium-based ionic liquid on the separation of azeotropic mixtures. The isobaric vapor liquid equilibrium data of n-propanol + water + [TMACl] and isopropanol + water + [TMACl] were measured at atmospheric pressure. The amount of [TMACl] required for eliminating the azeotrope for both the systems was found to be low compared to imidazolium ionic liquids reported earlier. For n-propanol + water system, the azeotrope was eliminated at [TMACl] mole fraction of 0.05, and for isopropanol + water system, the azeotrope was eliminated at a mole fraction of 0.026. The effect of [TMACl] on both the alcohol-water systems was explained in terms of relative volatility and activity coefficient.