THERMODYNAMICS OF THE TERNARY MIXTURE PROPAN-1-OL + TRIETHYLAMINE + NORMAL-HEPTANE - EXPERIMENTAL RESULTS AND ERAS-MODEL CALCULATIONS OF HE AND VE

Molar excess enthalpies (H(E)) and molar excess volumes (V(E)) of the liquid mixture Propan-1-ol (PrOH) + Triethylamine (TEA) + n-Heptane have been measured by flow calorimetry and the vibrating tube technique respectively. Data of the three binary systems have also been obtained. The excess properties are dominated by strong hydrogen bondings due to the self-association of PrOH and the association of PrOH with TEA. The third component, heptane, serves mainly as an inert diluting solvent. H(E) and V(E) are positive for PrOH + heptane and also for TEA + heptane to a much smaller extent. Strongly negative values of both H(E) and V(E) have been obtained for PrOH + TEA. The values obtained for the ternary system lie in between these extreme cases showing certain compositions where H(E) and V(E) vanish. - An extended version of the so-called ERAS model has been used for describing H(E) and V(E) of the complete ternary system. The parameters adjusted to the binary data reveal that the hydrogen bonding enthalpies and volumes between PrOH and TEA are distinctly stronger than between self-associating PrOH molecules. In addition the widely applied NRTL-model has also been used for describing H(E) of the ternary systems. V(E), however, can not be calculated with the NRTL model.