For separation of the azeotropes of n-propanol
(NPA) + water and isopropanol (IPA) + water by liquid–liquid
extraction, cyclohexanone was selected as the extraction solvent.
The liquid–liquid equilibrium (LLE) behavior of the two mixtures
(water + NPA + cyclohexanone) and (water + IPA + cyclohexanone) was
investigated at temperatures 298.15 and 308.15 K. The LLE phase diagrams
of the two mixtures belong to Treybal’s type I. According to
the measured data, distribution ratio and separation factor obtained
by calculation were used to analyze the extraction effect of cyclohexanone.
In addition, the NRTL and UNIQUAC models were used to fit the LLE
experimental data, and the values of root mean square deviation are
smaller than 0.007. Lastly, the analysis of Gibbs energy surfaces
was applied to validate the coherence of the fitted binary interaction
parameters for the thermodynamic models.