Y. Demirel et Ho. Paksoy, CALCULATIONS OF THERMODYNAMIC DERIVATIVE PROPERTIES FROM THE NRTL ANDUNIQUAC MODELS, Thermochimica acta, 303(2), 1997, pp. 129-136
The local composition models NRTL and UNIQUAC with temperature-depende
nt parameters have been employed to calculate the surfaces of excess h
eat capacity, C-p(E), excess enthalpy, h(E) and thermodynamic factor,
Gamma for binary liquid mixtures. These thermodynamic properties repre
sent the derivatives of the models with respect to temperature, C-p(E)
, h(E) and composition, Gamma. The parameters used in evaluating C-p(E
) and h(E) are directly obtained from separate C-p(E) and h(E) data at
different isotherms. Experimental g(E) and h(E) data at more than one
different isotherm are used simultaneously to estimate the parameters
in the evaluation of Gamma. The following mixtures are considered: me
thanol(1)-methyl acetate(2); 2-propanol(2)-n-heptane(2); methanol(1)-w
ater(2); benzene(1)-n-heptane(2) and ethanol(1)-water(2). These mixtur
es show close deviations between experimental and calculated values ob
tained from both models and also include associating mixtures. Perform
ances of the models based on different types of experimental data have
been compared. The models show considerable regional discrepancies of
the same thermodynamic property over the entire composition and tempe
rature ranges for the mixtures that show small overall deviations betw
een the calculated and experimental data. (C) 1997 Elsevier Science B.
V.