Deep eutectic solvents effect on vapor-liquid phase equilibrium for separation of allyl alcohol from its aqueous solution

Abstract

Allyl alcohol and water can form an azeotrope with the minimum boiling point. To separate allyl alcohol from its aqueous solution by distillation, the deep eutectic solvents (DESs) were applied to eliminate the azeotropic point. Two DESs choline chloride: glycerin (mole ratio of 1:1) and choline chloride: urea (mole ratio of 1:2) were selected. To validate the selected DESs for separation of allyl alcohol from its aqueous solution, the isobaric vapor-liquid equilibrium (VLE) data for the system of allyl alcohol + water + DESs were measured at pressure of 101.3 kPa. The relative volatility of allyl alcohol to water increased significantly by adding the DESs. With increasing the concentrations of the DESs, the azeotropic point of the system allyl alcohol + water moved and the azeotropic point was broken at last. Then, the COSMO model provides some theoretical insights into the separation mechanism. Meanwhile, the experimental VLE data were correlated by the NRTL model and the correlated results agreed with the measured data.