Thermodynamic properties of (a pentyl ester plus a n-alkane). XIV. The H-m(E) and V-m(E) for (an ester plus a n-alkane)

Abstract

This paper presents experimental data for the excess molar enthalpies HmE and excess molar volumes VmE at T = 298.15 K and atmospheric pressure for 21 binary mixtures consisting of one of three pentyl esters (ethanoate, propanoate, and pentanoate) and one of seven odd n-alkanes (from pentane to heptadecane). The results have shown the mixing of these mixtures to be endothermic, with HmE varying uniformly with the n-alkane chain length. The variation of VmE was also found to be uniform, with contraction effects observed for the mixtures that contained low molecular-weight hydrocarbons, and increasing with the pentyl ester chain length. Different group-contribution theories were used to calculate the excess properties for (an ester + an n-alkane). Comparison of the calculated and experimental results revealed that, in most cases, the differences increased with the molecular weight of the components. However, the differences for the calculated values of the excess volumes using the model of Nitta et al. decreased with n-alkane chain length but increased with ester chain length, the mean differences for the excess volumes being larger than 20 per cent. © 2001 Academic Press.