Analysis of excess enthalpies of ester+ 1-chloroalkanes with two group contribution models: primary parameters

Abstract

An analysis of the enthalpies of mixing, obtained experimentally at 298.15 K and at atmospheric pressure, of sixteen binary systems formed by four ethyl esters, from formate to butanoate, and four 1-chloroalkanes, from pentane to octane, is presented in this work. The experimental values of h E have been examined by a version of the UNIFAC model, as modified by Skjold-Jorgensen, as well as by the molecular group contribution model of Nitta. In both cases, the interaction parameters necessary for the prediction of the h E of the binary systems ester/1-chloroalkanes are determined, mainly the parameters involving the groups HCOO, COOC or COO, CH 3 or CH 2 and Cl. The predictions of h E, carried out both with the modified UNIFAC model and with the molecular model of Nitta, are similar. Thus, for the system ethyl formate+ 1-chloroalkanes, errors are lower than 6% with the UNIFAC model and less than 8% with that of Nitta. For the remaining systems, the errors increase as the chain length of the ester increases or as the h E decrease.