Aliphatic–Aromatic Separation Using Deep Eutectic Solvents as Extracting Agents

Abstract

The separation of aliphatic and aromatic compounds is a great challenge for chemical engineers. There is no efficient separation process for mixtures with compositions lower than 20 wt % in aromatics. In this work, the feasibility of two different deep eutectic solvents (DESs) as novel extracting agents for the separation of the mixture {hexane + benzene} were tested. In order to select the proper solvent for this separation, a solubility test of a set of DESs was done at room temperature and atmospheric pressure. The selected deep eutectic solvents for this work were (i) tetrahexylammonium bromide:ethylene glycol with molar ratio = 1:2 (DES 1) and (ii) tetrahexylammonium bromide:glycerol with molar ratio = 1:2 (DES 2). The selected DESs were characterized by measurement of density and viscosity at atmospheric pressure and temperatures T = 293.2–343.2 K. Next, the liquid–liquid equilibria (LLE) of the ternary systems {hexane + benzene + DES 1} and {hexane + benzene + DES 2} were determined at T/K = 298.2 ...