Thermodynamics of mixtures containing oxaalkanes. 5. Ether + benzene, or +toluene systems

Linear or cyclic ether + benzene or +toluene mixtures have been investigated in terms of the DISQUAC and UNIFAC (Dortmund version) models as well as using the Kirkwood–Buff formalism. The corresponding DISQUAC interaction parameters are reported. The QUAC interaction parameters are independent of the aromatic compound, and those for l = 1 (Gibbs energy) and l = 3 (heat capacity) are also independent of the ether. DISQUAC correctly describes a whole set of thermodynamic properties of these systems: vapour–liquid equilibria, VLE, solid–liquid equilibria, SLE, molar excess enthalpy, HmE, molar excess isobaric heat capacity, CpmE, and Kirkwood–Buff integrals. DISQUAC improves meaningfully UNIFAC HmE results, which remarks that the accurate description of this property is difficult when proximity effects or cyclization are present. From values of the molar excess enthalpies at infinite dilution obtained from HmE data available in the literature, it is concluded that the increase of the number of –O– atoms in the ether or cyclization leads to stronger interactions between unlike molecules. Values of the Kirkwood–Buff integrals and of linear coefficients of preferential solvation reveal that the structure of the investigated systems is close to random mixing.