Liquid–Liquid Equilibria of Benzene + Cyclohexane + N,N-Dimethyl Acetamide + Ammonium Thiocyanate at 298.15 K and Atmospheric Pressure

Abstract

The liquid−liquid equilibrium (LLE) data for the system of benzene + cyclohexane + N,N-dimethylacetamide (DMAc) + ammonium thiocyanate were measured experimentally at 298.15 K and atmospheric pressure. All the data were correlated by the nonrandom two liquid model and they matched well. The highest selectivity coefficients of the complex solvent (DMAc + NH 4 SCN) can reach 12.39 at 298.15 K, which is close to that of some ionic liquids. To investigate its similarity to ionic liquids, the complex solvent was tested for electrical conductivity, and the results show that the solvent is conductive, which means there are a lot of ions in the system. The existence of ions may help to extract benzene from cyclohexane, a theory which needs to be researched further in the future.

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

“…Moreover, the selectivity coefficient also increases by increasing the salt concentration in the DMF + KSCN system. The results presented in this work corroborate previous experimental data published in the literature, , where close values of selectivity coefficients were obtained, as well as the same behavior of the coefficient increase with the increasing salt content. Regarding the distribution coefficient, Dong et al obtained slightly lower distribution coefficients for 16% KSCN/DMF at slightly higher equilibrium temperatures.…”

“…Regarding the distribution coefficient, Dong et al 23 obtained slightly lower distribution coefficients for 16% KSCN/DMF at slightly higher equilibrium temperatures. By comparing the behaviors of distribution and selectivity coefficients obtained in this study with the ones of previous studies with similar systems, 20,23,24,37 one can notice that the SCN − anion presented better results when the K + cation was the salt pair (compared to Na + and NH 4 + ), with the parameters used in this study presenting the better results for selectivity and distribution coefficients than the cited ones.…”