Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

In this study, isobaric vapor-liquid equilibria (VLE) of the binary systems of methanol + nheptane 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.