The experimental data of excess molar enthalpies HM and excess molar volumes V-m(E) are presented for a set of 25 binary mixtures comprised of the first five methyl esters Cu-1H2u -1COOCH3 (u = 1 to 5) and five alpha,omega-dichloroalkanes, ClCH2(CH2)(v-2)CH2Cl (v = 2 to 6), obtained at a temperature of 298.15 K and atmospheric pressure. Except for the mixtures with u = 1 and v = 2 to 6, which are all endothermic and with u = 5 and v = 2 to 6, which are all exothermic, the others present net endo/exothermic effects and these mixing effects evolve quasiregularly, from endothermic to exothermic, depending on the dichloroalkane present. However, the Vm are positive in most mixtures except for those corresponding to u = 4,5 and v = 5, 6, which present contraction effects. These results indicate a set of specific interactions with simultaneous effects for Vm of expansion/contraction and for exothermic/endothermic Hm for this set of mixtures. The change in Vm with the chain length of the compounds is irregular. To achieve a good application of the UNIFAC model using the version of Dang and Tassios, parameters of the ester (G)/dichloride (G') interaction were calculated again, making a distinction, during its application, dependent on the acid part of the ester u. Hence, interaction parameters are presented as a function of u, and of the dichloroalkane chain length v. The most appropriate general expression was of the type: aG/G' = omega (u, v) = Sigma(n)(i=0)ai-u(i-1) + Sigma(n)(i=0)bi-1v(i-1) and with this proposal good estimations of enthalpies were obtained with the UNIFAC model. (C) 2006 Elsevier Ltd. All rights reserved.