Experimental determination of densities and isobaric vapor-liquid equilibria of binary mixtures formed by a propyl alkanoate (methanoate to butanoate) plus an alkan-2-ol (C-3, C-4)

Abstract

Vapor-liquid equilibria at 101.32 kPa of binary systems composed of the first four propyl esters, from methanoate to butanoate, and propan-2-ol or butan-2-ol and the vapor pressures of the pure components were measured in the same equilibrium still. The densities and excess volumes for the same mixtures were also determined at 298.15 K. The binary systems studied presented a positive deviation from ideality, and four of the mixtures had azeotropes at the working pressure, namely, propyl methanoate (1) + propan-2-ol (2) at x1 = 0.570 and T = 349.4 K, propyl methanoate (1) + butan-2-ol (2) at x1 = 0.933 and T = 353.6 K, propyl ethanoate (1) + propan-2-ol (2) a x1 = 0.037 and T = 355.2 K, and propyl ethanoate (1) + butan-2-ol (2) at x1 = 0.423 and T = 370.8 K. The isobaric VLE quantities were correlated together with the mixing enthalpies obtained for the corresponding mixtures using a suitable equation containing temperature-dependent parameters. The ASOG and UNIFAC group-contribution models were used to predict the VLE values.