Thermodynamics of mixtures with strongly negative deviations from Raoult'slaw - Part 2. Application of the DISQUAC model to mixtures of CHCl3 or CH2Cl2 with oxaalkanes. Comparison with Dortmund UNIFAC results

Binary mixtures of linear and cyclic oxaalkanes and CHCl3 or CH2Cl2 are cha racterized in the framework of the DISQUAC model. The interaction parameter s for the corresponding O/Cl contacts are reported. The enthalpic quasichem ical interchange coefficients are negative, as in other mixtures which also show strong negative deviations from Raoult's law. There are proximity eff ects on both dispersive and quasichemical interaction parameters of diether s and acetals. DISQUAC represents fairly well the thermodynamic properties examined: vapor-liquid equilibria (VLE), molar excess enthalpies (H-E), mol ar excess heat capacities at constant pressure (C-p(E)) or natural logarith ms of activity coefficients at infinite dilution (ln gamma(i)(infinity)). D ISQUAC provides much better results than the Dortmund version of UNIFAC usi ng the published geometrical and interaction parameters. From this comparis on, it seems that one should distinguish, at least, between linear monoethe rs, polyethers or acetals. Each cyclic molecule should be treated separatel y. A short comparison between DISQUAC and the ideal associated solution the ory is also included. Both models yield similar results.