Proximity effects and cyclization in oxaalkanes+CCl 4 mixtures DISQUAC characterization of the Cl–O interactions. Comparison with Dortmund UNIFAC results

Abstract

Thermodynamic properties, vapor–liquid equilibria (VLE), molar excess Gibbs energies ( G E), molar excess enthalpies ( H E) and natural logarithms of activity coefficients at infinite dilution (ln γ i ∞) or partial molar excess enthalpies at infinite dilution ( H i E,∞) of mixtures of oxaalkanes, linear or cyclic monoethers, diethers or acetals, and CCl 4 are studied in the framework of DISQUAC. The oxygen/CCl 4 contacts are characterized by dispersive (DIS) and quasichemical (QUAC) interaction parameters, which are reported. Contacts of the type (polar group)/CCl 4 are usually characterized by DIS parameters only. The effects of proximity and cyclization on the interchange coefficients are examined. In comparison with systems of oxaalkanes and n-alkanes, some differences exist; e.g., linear monoethers and diethers+CCl 4 mixtures are represented by different interaction parameters due to proximity effects of oxygen atoms (i.e., –O–C–C–O–) in diethers. In solutions with cyclic molecules, ring strain seems to be now more important. DISQUAC results are compared with those obtained using the Dortmund version of UNIFAC. From this comparison, it is concluded that it is necessary to distinguish at least between monoethers, diethers and acetals when treating mixtures with oxaalkanes and that each cyclic molecule should be characterized by its own set of interaction parameters.