Termodinamica quimica

Fluid Phase Equilibria 338 (2013) 16–22

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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
Dana Dragoescu ∗ , Mariana Teodorescu, Daniela Gheorghe
“Ilie Murgulescu” Institute of Physical Chemistry, Splaiul Independentei 202, 060021 Bucharest, Romania

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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 Barker’s 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 Raoult’s law. The experimental VLE data were analyzed in terms of the modified UNIFAC (Dortmund) model. © 2012 Elsevier B.V. All rights reserved.

Article history: Received 26 July 2012 Received in revised form 16 October 2012 Accepted 17 October 2012 Available online 26 October 2012 Keywords: Vapor–liquid equilibria Excess Gibbs energy Mixtures Nitroalkanes Chloroalkanes

1. Introduction Nitroalkanes and chloroalkanes represent classes of technically important compounds used in industry as intermediates for organic synthesis or as final products. Nitromethane is a polar liquid used as a solvent in a variety of industrial applications, such as in extractions, as a reaction medium, and as a cleaning solvent. Nitroethane