Proximity effects and cyclization in oxaalkanes plus CCl4 mixtures DISQUACcharacterization of the Cl-O interactions. Comparison with Dortmund UNIFACresults

Thermodynamic properties, vapor-liquid equilibria (VLE), molar excess Gibbs energies (G(E)), molar excess enthalpies (H-E) and natural logarithms of a ctivity coefficients at infinite dilution (ln gamma(i)(infinity)) or partia l molar excess enthalpies at infinite dilution (H-i(E,infinity) ) of mixtur es of oxaalkanes, Linear or cyclic monoethers, diethers or acetals, and CCl 4 are studied in the framework of DISQUAC. The oxygen/CCl4 contacts are cha racterized bg dispersive (DIS) and quasichemical (QUAC) interaction paramet ers, which are reported. Contacts of the type (polar group)/CCl4 are usuall y characterized by DIS parameters only. The effects of proximity and cycliz ation on the interchange coefficients are examined. In comparison with syst ems of oxaalkanes and n-alkanes, some differences exist; e.g., linear monoe thers and diethers + CCl4 mixtures are represented by different interaction parameters due to proximity effects of oxygen atoms (i.e., -O-C-C-O-) in d iethers. In solutions with cyclic molecules, ring strain seems to be now mo re important. DISQUAC results are compared with those obtained Lsing the Do rtmund 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. (C) 1999 Elsevi er Science B.V. All rights reserved.