Liquid–Liquid Equilibrium for Cyclohexane + Benzene + N,N-Dimethylformamide + Potassium Thiocyanate at Temperature 298.15 K and Atmospheric Pressure

Abstract

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.

COSMO Study on the Heptane–Toluene–DMF/DEG-KSCN Liquid–Liquid Equilibrium System

“…The separation of aromatic/aliphatic hydrocarbons, such as n-heptane and toluene, may be improved by combining compounds that are inexpensive and present good efficiency when combined. 12 Dimethylformamide (DMF) is a conventional aprotic polar solvent for organic reactions. Its application as a solvent in the LLE process of aliphatic/aromatic systems demonstrated good results.…”

“…It makes the separation process disadvantageous from an economic point of view, and the use of more conventional solvents may further improve the LLE in this perspective. The separation of aromatic/aliphatic hydrocarbons, such as n -heptane and toluene, may be improved by combining compounds that are inexpensive and present good efficiency when combined …”