Extraction of allyl alcohol from its aqueous solution using two different ionic liquids: Intermolecular interaction and liquid-liquid phase equilibrium explorations

Abstract

Allyl alcohol is a remarkable chemical intermediate. During its preparation by allyl acetate hydrolysis, an aqueous mixture is usually obtained. Because allyl alcohol can form a minimum boiling point azeotropic mixture with water, it is impossible to separate such a mixture by conventional distillation. In this work, for recovering allyl alcohol by extraction, the ionic liquid extractants (ILs) were adopted by the model of COSMO-SAC and two ILs 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP][Tf2N]) and 1-octyl-3-methylimidazolium trifluoromethanesulfonate ([OMIM][OTf]) were selected. The length of the hydrogen bond and the energy of the interaction between the ILs and (allyl alcohol/water) were calculated by quantum chemical calculations. The experimental liquid–liquid phase equilibrium (LLE) data for the ternary systems (water + allyl alcohol + [OMIM][OTf]/[BMP][Tf2N]) were explored at 298.15 K. The [OMIM][OTf] and [BMP][Tf2N] extraction capability was assessed with selectivity and partition ratio. In addition, the NRTL model was used to fit the measured tie-line values.