| Abstract
| - In this work, we report the experimental values of the excess quantitiesandand the isobaric equilibriumdata (VLE) at 101.32 kPa for the four mixtures of alkyl methanoates (methyl to butyl) and hexane. The resultsindicate that for these four mixtures (∂/∂T)p> 0 and(∂/∂T)p> 0. VLE data were found to bethermodynamically consistent with the Fredenslund method. All the binary mixtures presented here, except forthe system (butyl methanoate + hexane), present a minimum-boiling temperature azeotrope with coordinates(xaz, Taz/K), (0.832, 302.62) for (methyl methanoate + hexane), (0.703, 323.32) for (ethyl methanoate + hexane),and (0.283, 339.10) for (propyl methanoate + hexane). Simultaneous correlations performed with the VLE dataand excess enthalpies using a simple polynomial model, with temperature-dependent coefficients, producedacceptable estimations. Application of the UNIFAC model in the versions of Hansen et al. (Ind. Eng. Chem. Res.1991, 30, 2355−2358) and Gmehling et al. (Ind. Eng. Chem. Res. 1993, 32,178−193) produced similar predictionsfor all four systems, of which only the ones for the methyl methanoate + hexane mixture are acceptable. Differencesincrease steadily with increasing methanoate chain length. Estimation of enthalpies with the second of the versionsindicated, however, produced mean errors of 10 %, which could be considered as acceptable.
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