VAPOR-LIQUID EQUILIBRIA OF TOLUENE + n-BUTANOL AND TOLUENE + n-BUTANOL + CALCIUM CHLORIDE AT 94.0kPa

Abstract

Vapor-liquid equilibrium data of toluene + n-butanol and toluene+ n-butanol + CaCl2 (at saturation) were measured at a pressure of 94.0 kPa, using a modified Malanowski equilibrium still. The salt investigated in this work, i.e., CaCl2, exhibits a slight salting-out effect on toluene. The experimental results of the salt-free binary were compared with those obtained from NRTL, ASOG, and UNIFAC models. The latter two models predicted the bubble-point temperatures within 0.5 K (as a root mean square deviation, RMSD) whereas the NRTL model, which was employed to establish thermodynamic consistency by directly fitting the experimental data, correlated the bubble-point temperatures with an RMSD of 0.2 K. On the other hand, the experimental data of toluene+n-butanol+CaCl2 were compared with those predicted by the NRTL-Tan model for the effect of the electrolyte. This model predicted the bubble-point temperatures with an RMSD of 0.5 K. Calcium chloride has been shown not to have a sensible effect on the azeotropic composition.