Separation of ethylbenzene and n-octane using deep eutectic solvents

Abstract

In this work, we have investigated the possibility of using low cost ionic liquid analogues, namely deep eutectic solvents (DESs), for the liquid-liquid extraction of ethylbenzene from n-octane. The DESs used in this work were synthesized from ammonium salt with ethylene glycol and sulfolane as complexing agents. Equilibrium data for the ternary system consisting of ethylbenzene, n-octane and the DES were measured at 25°C and atmospheric pressure. The solvent formed by mixing tetraethyl-ammonium p-toluenesulfonate and sulfolane showed the best performance, i.e., the highest distribution ratio and selectivity. The complexing agents were not found in the raffinate phase. This will facilitate the separation process protocol and hence reduce the cost of the process. Finally, the experimental data was satisfactorily correlated using the NRTL model, showing that this classical model can easily be adopted with systems such as DESs.