Liquid-liquid equilibria and COSMO-SAC modeling of organic solvent/ionic liquid - hydroxyacetone - water mixtures

In this work conventional organic solvents (ethyl acetate, n-propyl acetate, n-butyl acetate, chloroform) as well as ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][Tf2N]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]), were investigated for the extraction of hydroxyacetone from aqueous solution. The liquid-liquid equilibrium (LLE) data for the ternary systems were experimentally determined at T = 298.15 K and atmospheric pressure. In terms of the distribution coefficient and selectivity, [EMIM][Tf2N] and [BMIM][Tf2N] were found to be the most effective solvents for the extraction of hydroxyacetone from aqueous solution, and the composition of ionic liquids in the raffinate phase was found to be negligible. The experimental results were correlated with the NRTL and UNIQUAC models. The root mean square deviations (RMSD) obtained between the NRTL and UNIQUAC correlations for all the systems were in the range of 0.19-5.18%. COSMO-SAC was then used to make a first principles prediction of the phase equilibria of the systems studied. For the organic solvent-based systems, the deviations between predicted and experimental values were in the range of 3.49-8.00% (% RMSD) whereas for the ionic liquid systems, the deviations were in the range of 16.81-18.53%.