Vapor-liquid equilibrium has been measured at 333.15 K for the following binary mixtures: acetonitrile (3) + 1-chlorobutane (1), ethanol (2) + 1-chlorobutane (1), and ethanol (2) + acetonitrile (3) at 333.15 K. Values of the maximum of G(E) ranging from 700 J.mol(-1) to 1150 J.mol(-1) were found for the three systems. Consistency with data already published at different temperatures has been demonstrated as well as with experimental excess enthalpy for the ethanol + acetonitrile mixture. The results have been used to test the ability of a lattice-fluid theory to fit the G(E) and to predict the H(E) and V(E) excess functions. Although reasonable fits were found for the systems containing ethanol, worse results were found for 1-chlorobutane + acetonitrile. In general, the theoretical predictions of H(E) and V(E) are rather poor when the binary energy parameter of the theory is fitted to G(E).