Separation of methyl acetate + methanol azeotropic mixture using ionic liquids as entrainers

• Isobaric VLE data for three ternary systems containing ILs were measured at 101.3 kPa.
• The addition of ILs produced a strong salting-out effect on methyl acetate and enhanced the relative volatility of methyl acetate to methanol.
• The salting-out effect of three ILs follows the order: [C4MIM][Cl] > [ClC2MIM][Cl] > [C4MIM][Br].
• Ternary VLE data were well correlated by NRTL model.

Three ionic liquids (ILs), namely 1-butyl-3-methylimidazolium chloride ([C4MIM][Cl]), 1-(2-chloroethyl)-3-methylimidazolium chloride ([ClC2MIM][Cl]) and 1-butyl-3-methylimidazolium bromide ([C4MIM][Br]), were investigated as entrainers for the separation of azeotropic mixture of methyl acetate and methanol. Isobaric vapor–liquid equilibrium (VLE) data for the ternary systems containing ILs were measured in a recirculating still at 101.3 kPa. It was found that all the three ILs produced a salting-out effect on methyl acetate, thus enhancing the relative volatility of methyl acetate to methanol. The salting-out effect of the ILs employed in this study follows the order: [C4MIM][Cl] > [ClC2MIM][Cl] > [C4MIM][Br]. Moreover, [C4MIM][Cl] could eliminate the azeotropic point at a mole fraction of 0.134. The experimental data were well correlated with the nonrandom two-liquid (NRTL) model.

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