Isobaric
vapor–liquid equilibria (VLE) of the binary systems
of methanol + n-heptane and 1-butanol + aniline were
measured at 85 kPa. The experiments were carried out using an Othmer
still with the objective of measuring the equilibrium temperature,
as well as the composition of the vapor and liquid phases as determined
by gas chromatography analysis. According to the experimental results
obtained, both of the binary mixtures studied demonstrate positive
deviation from ideal behavior. Furthermore, a point of minimum-boiling
azeotrope was observed for the methanol + n-heptane
system. The VLE data measured have been verified to be thermodynamically
consistent based on the Wisniak modification of the Herington area
test for isobaric VLE data. Additionally, the two systems were thermodynamically
modeled. Because of the relatively low pressure involved in this work,
the modified Raoult’s law was utilized for this purpose. In
this regard, the experimental vapor–liquid equilibrium data
were correlated with different excess Gibbs energy models, including
the Wilson, the nonrandom two-liquid (NRTL), and the universal quasi-chemical
(UNIQUAC) activity coefficient models. The results obtained show reasonably
good agreement with the experimental data.