Isothermal vapor–liquid equilibria and excess Gibbs free energies in some binary nitroalkane + chloroalkane mixtures at temperatures from 298.15 K to 318.15 K

The vapor pressures of binary mixtures of cloroalkane (1-chlorobutane, 1-chloropentane) + nitromethane or nitroethane were measured at temperatures between 298.15 K and 318.15 K. The vapor pressures vs. liquid phase composition data have been used to calculate the activity coefficients of the two components, and the excess molar Gibbs energies GE for the mixtures, using Barkerʹs method. Redlich–Kister, Wilson, NRTL and UNIQUAC equations, taking into account the vapor phase imperfection in terms of the 2-nd virial coefficient, have represented the GE values. No significant difference between GE values obtained with these equations has been observed. The results indicate that all the systems show positive deviations from Raoultʹs law. The experimental VLE data were analyzed in terms of the modified UNIFAC (Dortmund) model.