Transesterification reactions are common in the production of some important chemicals, such as biodiesel and mono- and diglycerides. Knowledge of the phase equilibrium conditions of the reactive mixture is essential to explore possible operating conditions for the reactor and the downstream separation process. In this work, liquidliquid and vaporliquidliquid equilibrium data have been measured for the ternary system methyl oleatemethanolglycerol, at temperatures between 313 and 393 K. The group contribution with association equation of state (GCA-EOS) and the A-UNIFAC model were applied to represent the phase equilibria of this ternary system. Self-association in glycerol and methanol and cross-association with methyl esters were taken into account.

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Densities, viscosities and refractive indices have been measured at 298.15 K and atmospheric pressure for binary and ternary mixtures of ethanol, ethyl acetate and 1-butyl-3methyl-imidazolium bis(trifluoromethylsulfonyl) imide [C 4 mim][NTF 2 ]. From these experimental properties, the corresponding excess properties have been calculated and adequately fitted with the Redlich-Kister polynomial equation. The adjustable parameters and standard deviations between experimental and calculated values are reported. Interest of this mixture is due to the possibility of using [C 4 mim][NTF 2 ] as an entrainer in the extractive distillation of ethanol + ethyl acetate. These results are compared with previously determined experimental data for mixtures of ethyl acetate and/or ethanol with the ionic liquid 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide, [C 8 mim][NTF 2 ].

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Systems that form azeotropes or have relative volatilities close to 1.0 represent very little energy and capital intensive separations. Ionic liquids (ILs) can serve as nonvolatile entrainers to break azeotropes and enable a more energy efficient and environmentally friendly process. Here, six ILs have been investigated for their ability to break the ethanol + ethyl acetate azeotrope at 313.15 K. Three of the ILs investigated, 1-ethyl-3-methyl-imidazolium methanesulfonate [emim]­[MeSO3], 1-ethyl-3-methyl-imidazolium methylsulfate [emim]­[MeSO4], and 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate [bmim]­[CF3SO3] are excellent entrainer candidates. In fact, the ethanol + ethyl acetate azeotrope can be broken over the entire composition range by adding as little as 2.5 mol percent of either [emim]­[MeSO3] or [emim]­[MeSO4] to the binary organic mixture, which is less IL than what is needed to break any azeotropic system discussed in literature to date. The other three ILs, 1-ethyl-3-methyl-imidazolium bis­(trifluoromethylsulfonyl)­imide [emim]­[Tf2N], 1-hexyl-3-methyl-imidazolium bis­(trifluoromethylsulfonyl)­imide [hmim]­[Tf2N], and 1-butyl-1-methyl-pyrrolidinium bis­(trifluoromethylsulfonyl)­imide [bmpyrr]­[Tf2N], are limited in their ability to break this azeotrope. The difference between these two groups correlates with the infinite dilution activity coefficients of the ethyl acetate and ethanol in each of the ILs. Both polarity and hydrogen bonding are important in determining the preferential affinity of the ethanol for the ILs, which raises the ethyl acetate/ethanol relative volatility. In addition, the experimental binary and ternary vapor–liquid equilibrium data have been fit to the Non Random Two Liquid (NRTL) activity coefficient model, which is able to predict and correlate the amount of IL needed to break the azeotrope in these ternary vapor–liquid equilibrium systems.

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