Phase equilibria of the water + 1-butanol + toluene ternary system at 101.3 kPa

•The phase equilibria of the system water + 1-butanol + toluene have been studied.•Isothermal liquid–liquid equilibrium data at 313.15 K was determined.•Isobaric vapour–liquid–liquid equilibrium data at 101.3 kPa was also determined.•Data obtained has been checked against literature data and those predicted with binary interaction parameters.•All experimental data have been correlated with thermodynamic models.

Isobaric vapour–liquid and vapour–liquid–liquid equilibrium data for the water + 1-butanol + toluene ternary system were measured at 101.3 kPa with a modified VLE 602 Fischer apparatus. In addition, the liquid–liquid equilibrium data at 313.15 K were measured and compared with data from other authors at different temperatures. The system exhibits a ternary heterogeneous azeotrope whose temperature and composition have been determined by interpolation. The thermodynamic consistency of the experimental vapour–liquid and vapour–liquid–liquid data was checked by means of the Wisniak’s Li/Wi consistency test. Moreover, the vapour–liquid and the liquid–liquid equilibrium correlation for the ternary system with NRTL and UNIQUAC models, together with the prediction made with the UNIFAC model, were studied and discussed.