This work presents the measurements of H-m(E) and V-m(E), obtained at a temperature of T = 318.15 K and atmospheric pressure for a set of 30 binary mixtures composed of five alkyl ethanoates (methyl to pentyl) with six odd n-alkanes (C-7 to C-17). The results show that the mixing processes are endothermic in all cases, with regular increases in H-m(E) with the molecular weight of the saturated hydrocarbon and diminishing with the alkanolic part of the ester. The change in V-m(E) is also regular and similar to that of H-m(E). For data correlation, a new form of polynomial equation is used. In this, the so-called active fraction is used as a variable which, in turn, depends on the concentration of the mixture, giving acceptable estimations of the Gibbs function obtained in the isobaric (liquid + vapor) equilibria for some of the mixtures studied. Finally, a molecular model which interprets the behavior of mixtures of alkyl ethanoates + n-alkanes and the results of residual quantities is proposed. To these binary systems some group contribution models are applied. A modified version of the UNIFAC model gives satisfactory results for enthalpies. (C) 2004 Elsevier Ltd. All rights reserved.