Vapor-liquid equilibria for binary systems composed of a propyl ester (ethanoate, propanoate, butanoate) + an n-Alkane (C(7), C(9))

Abstract

This paper reports isobaric vapor-liquid equilibrium measurements made using a small equilibrium still at a pressure of 101.32 kPa and other excess properties for a set of six binary mixtures composed of one of three propyl esters (ethanoate, propanoate, butanoate) and one of two n-alkanes (heptane, nonane). The vapor pressures for the n-alkanes measured using the same equilibrium still and the correlations calculated are also presented. Application of the point-to-point test showed the systems studied to be consistent. All the data were correlated, and processing of the equilibrium data included the excess enthalpies. The system consisting of propyl ethanoate + heptane has an azeotrope at xaz = 0.423, Taz = 366.9 K, and the system consisting of propyl butanoate + nonane has an azeotrope at xaz = 0.726, Taz = 414.4 K. Both the modified-UNIFAC theoretical model and the Nitta model yield acceptable estimates of the different properties for these propyl ester + n-alkane mixtures.