Isobaric Vapor–Liquid–Liquid Phase Equilibria Measurements of Three Ternary Water + 2-Butanone + Aliphatic Alcohol (Ethanol, 1-Propanol, 2-Propanol) Systems at 101.3 kPa

Vapor–liquid–liquid equilibrium (VLLE) data were measured for the ternary systems water + 2-butanone + alcohol at 101.3 kPa by means of a Gillespie type still equipped with an ultrasonic homogenizer. VLLE were observed in the temperature ranges of 346.65–346.79 K, 346.74–352.70 K, and 346.52–346.75 K for the water + 2-butanone + ethanol, water + 2-butanone + 1-propanol, and water + 2-butanone + 2-propanol systems, respectively. For all three systems, a region of liquid–liquid immiscibility was observed, and the vapor phase compositions were outside the liquid–liquid phase envelope. The absence of ternary heterogeneous azeotropes was thus established. The nonrandom two-liquid (NRTL), universal quasichemical (UNIQUAC), and universal functional (UNIFAC) activity coefficient models were used for comparison with experimental results. The parameters were fitted to the binary subsystems vapor–liquid and liquid–liquid equilibrium experimental data. While correct estimations of experimental vapor phase trends were obtained, all three activity coefficient models failed to provide a fair description of the size of the heterogeneous region. Overall, the thermodynamic modeling results were poor, emphasizing the need for experimental data and application of advanced thermodynamic models.