ENTHALPY OF MIXING WITH H-BONDS INTERACTIONS - THE ROLE OF THE REACTIONAL CONTRIBUTIONS

A theoretical model is given to split the experimental heat of mixing into contributions from pure mixing and chemical reactions, when associations between the components occur in the binary system. The mixtures studied in this paper are 1,3-dioxolane + acetic acid and 1,3-dioxolane + trichloroethylene, whose calorimetric data were obtained previously. To obtain a realistic association pattern, NMR measurements are carried out. The mixtures were assumed non-ideal, and an extended regular solution model was used to calculate the activity coefficients of each component. From the comparison between experimental and calculated heats of mixing, the equilibrium constants of association reactions are calculated. The reliability of the fit is discussed.