An ebulliometric method was examined for determining the vapor-liquid equilibrium on binary systems consisting of close-boiling components. The boiling points of five binary systems were measured (ethylbenzene and m-xylene, o-chlorotoluene and p-chlorotoluene, benzene and cyclohexane, carbon tetrachloride and ethylacetate, and heptane and methylcyclohexane) at the pressure of 40.00-93.32 kPa. The vapor-liquid equilibria were determined by the Wilson equation from the experimental boiling points. In addition, the infinite dilution activity coefficients were calculated from the boiling point and their thermodynamic consistency was checked on the basis of the Gibbs-Helmholtz equation. (c) 2007 Elsevier B.V. All rights reserved.