Homogeneity of the water + ethanol + toluene azeotrope at 101.3 kPa

An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer has been used in the determination of the vapour–liquid equilibrium (VLE) and vapour–liquid–liquid equilibrium (VLLE). Consistent data for the ternary water + ethanol + toluene system are reported at 101.3 kPa at temperatures in the range of 347–357 K. These data have been compared with previously published VLLE data. The experimental data indicate that a ternary azeotrope is present at 347.60 K. It has been determined experimentally that the ternary azeotrope is homogeneous and not heterogeneous as is claimed in some of the studied references. The experimental results have been used to check the accuracy of the UNIFAC, UNIQUAC and NRTL models, proving that these models predict a bigger heterogeneous region than the experimental one.