The liquid–liquid extraction
is an important industrial
separation process. It is suitable to separate components with close
boiling points when common separation processes such as fractionated
distillation are infeasible. The liquid–liquid equilibria of
mixtures containing cyclohexane + benzene + N,N-dimethylformamide (DMF) + potassium thiocyanate (KSCN)
were analyzed by experimental data obtained at 298.15 K and atmospheric
pressure. The obtained experimental data presented good correlation
with UNIQUAC and e-NRTL models. The effectiveness of associating KSCN
to DMF was analyzed to improve the separation of aromatic and aliphatic
hydrocarbons. The liquid–liquid equilibrium selectivity and
distribution coefficients were evaluated, considering different KSCN
proportions in the solvent. The results demonstrated that the selectivity
coefficient increases as the salt mass increases in the mixture. On
the other hand, the distribution coefficient decreases as the benzene
concentration increases in the raffinate phase.