Vapor–liquid equilibria of iso-propanol iso-butanol and iso-propanol iso-butanol calcium chloride at 93.6 kPa

Vapor–liquid equilibrium (VLE) data of iso-propanol iso-butanol and iso-propanol iso-butanol CaCl2 (at saturation) were measured at a pressure of 93.6 kPa, using a modified Malanowski equilibrium still. The VLE behavior of the salt-free system is nearly ideal with a maximum normalized excess Gibbs energy (GE:RT) of 0.01. The salt investigated in this work, i.e. CaCl2, shows no effect on the phase behavior of iso-propanol iso-butanol. The experimental results of the salt-free binary were compared with those predicted by the ASOG and UNIFAC models, which predicted the bubble-point temperatures with an RMSD (root mean square deviation) of 1.01 and 1.26 K, respectively. The former model, however, predicted the vapor-phase composition within 0.012 mole fraction while the latter predicted them within 0.016 mole fraction in terms of RMSD. Moreover, two isobaric data sets (at 760 mm Hg) from the literature were analyzed using the above two models