Thermodynamic properties of (an ester plus an alkane). XVIII. Experimental H-m(E) and V-m(E) values for (an alkyl butanoate plus an alkane) at T=318.15 K

摘要

This work presents the experimental values of H-m(E) and V-m(E) obtained at a temperature of 318.15 K and atmospheric pressure for a group of 24 binary mixtures comprised of the first four alkyl butanoates (methyl to butyl) with six odd alkanes, from heptane to hep tadecane. All the mixtures are endothermic, and present a regular increase in H-m(E) with the molecular weight of the saturated hydrocarbon, while, for a same alkane, the enthalpic effects diminish with increasing alcoholic chain of the butanoate. The variation in V-m(E) occurs in the same direction. In this paper the structural behaviour of these systems and the influence of temperature on excess properties are analysed. Experimental data are correlated with a suitable polynomial equation which is given as a function of concentration and temperature, that permits a simultaneous correlation to be established with other properties of the mixture, such as (vapour + liquid) equilibria; and acceptable results are obtained. Finally, an estimation of H-m(E) is made with two known versions of the UNIFAC model. In the version by Dang and Tassios [J. Dang, D.P. Tassios, Ind. Eng. Chem. Process Des. Dev. 25 (1986) 22-31.], a method is proposed that considers the interaction parameters as a function of the butanoate alkanolic chain. The estimations obtained for H-m(E) are good. (c) 2007 Elsevier Ltd. All rights reserved.