Measurement and Correlation of Vapor–Liquid Equilibrium Data of the Toluene, o-Chlorotoluene, and p-Chlorotoluene System at 101.3 kPa

Toluene, an excellent organic solvent, is used in various chemical reactants and carbon nanomaterials, and its recycling can potentially alleviate related environmental problems. Isobaric vapor–liquid equilibrium (VLE) data at 101.3 kPa for (toluene + o-chlorotoluene), (toluene + p-chlorotoluene), and (o-chlorotoluene + p-chlorotoluene) were measured in this study. The experimental data were tested using the Fredenslund test and the Van Ness test. NRTL, Wilson, and UNIQUAC models were employed to correlate the new VLE data, depicting that all models were fitted well. The above three activity coefficient models were used to regress the binary interaction parameters, where the root-mean-square deviation (RMSD) and the average absolute deviation (AAD) results indicated that the experimental and thermodynamic model data were within a reasonable range. Although VLE data showed that the binary systems are non-azeotropic, toluene and o-chlorotoluene, or toluene and p-chlorotoluene are well separated by rectification, and the separation of o-chlorotoluene and p-chlorotoluene using distillation may need a significant number of stages.