Vapor pressure and isobaric vapor–liquid equilibrium for dichloronitrobenzene isomers

The saturated vapor pressures of pure 3,4-dichloronitrobenzene and 2,3-dichloronitrobenzene and the isobaric vapor–liquid equilibrium (VLE) data for binary 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene system under 20.00 kPa, 60.00 kPa and 101.30 kPa were measured experimentally using an inclined ebulliometer. The saturated vapor pressure was correlated by an Antoine equation. Thermodynamic consistency of the vapor–liquid equilibrium data was tested by means of Herington semi-empirical method, and the vapor–liquid equilibrium data were correlated with Wilson, NRTL and UNIQUAC activity coefficient models. The parameters of the three thermodynamic models were obtained by a nonlinear least-square regression method. All the three models can describe the measured vapor–liquid data satisfactorily. The vapor pressures and the vapor–liquid equilibrium data presented in the paper are essential for the design and operation for separation of the isomeric mixture of 3,4-dichloronitrobenzene + 2,3-dichloronitrobenzene via distillation.