Effect of anion fluorination in 1-ethyl-3-methylimidazolium as solvent for the liquid extraction of ethanol from ethyl tert-butyl ether

In this work, we have studied the use of homologous imidazolium-based ionic liquids (i.e. with the same fluorinated and non-fluorinated anion) to perform the separation of an ether and an alcohol. Concretely, we have selected ethyl tert-butyl ether (ETBE) and ethanol due to the capital interest of their industrial separation. Liquid–liquid equilibrium (LLE) data for the ternary systems involved are presented. It has been found that 1-ethyl-3-methylimidazolium methanesulfonate leads to higher values of solute distribution ratios and selectivities than 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, except for selectivity values at high solute concentrations. In addition, LLE data have been adequately correlated by means of the NRTL equation.