Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

This article presents the experimental data of HE and V E, obtained at atmospheric pressure and at a temperature of 298.15 K, for a set of 25 binary mixtures composed of the first 5 ethyl alkanoates (methanoate to pentanoate) and five a,x-dichloroalkanes (1,2-dichloroethane to 1,6-dichlorohexane). Quantitatively, and with only a few exceptions, small values are obtained for the excess properties and the results imply that specific interactions exist between both types of compounds, with exothermic process for most mixtures, but with the exception of some that contain ethyl methanoate and ethanoate. The change in enthalpies with increasing length of the dichloroalkane chain for the same ester is regular, and also the change in HE with the acid portion of the ethyl ester. However, the change in excess volumes does not present such a regular variation. A behavioural structural model is established to explain the results of the excess properties. Experimental values of HE and V Ewere correlated, as a function of ester concentration, x with a new expression which uses the so-called active fraction as a variable and which, in turn, is a function of this concentration. The application of two versions of the UNIFAC group contribution models produces no good estimations of HE.