Phase equilibria Study of the (benzene+ cyclohexane+N,N-dimethylformamide+ potassium thiocyanate) quaternary systems

This work demonstrates the ability of N,N-dimethylformamide + potassium thiocyanate(DMF + KSCN) to act as a novel complex solvent for the removal of benzene from its mixture with cyclohexane. The (liquid + liquid) equilibria (LLE) were measured for a quaternary system of (DMF + KSCN + benzene + cyclohexane) under atmospheric pressure and at temperature 298.15 K. The tie-line data for quaternary mixtures of (DMF + KSCN + benzene + cyclohexane) are also presented. The selectivity coefficients from these LLE data were calculated and found to be better than those previously reported in the literature for the (DMF + benzene + cyclohexane) systems. Excellent correlation of data by the nonrandom two-liquid (NRTL) model was seen for the quaternary system and the predicted results were found to be in fairly good agreement with experimental data.