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.

Activity coefficients at infinite dilution (γ i ∞ ) of alkanes, alkenes, and alkylbenzenes as well as of the linear and branched C 1 -C 7 alcohols, esters, and aldehydes in the ionic liquids 1-methyl-3-butylimidazolium bis(trifluoromethyl-sulfonyl) imide were determined by gas chromatography using the ionic liquid as stationary phase. The measurements were carried out at different temperatures between 302 K and 385 K. From the temperature dependence of the limiting activity coefficients, partial molar excess enthalpies at infinite dilution (H i E,∞ ) of the solutes in the ionic liquids have been derived.

The (solid + liquid) phase equilibria and (liquid + liquid) phase equilibria of binary mixtures containing quaternary phosphonium salt-tetrabutylphosphonium methanesulfonate and alcohols or alkylbenzenes were investigated. The systems {[(CH(3)CH(2)CH(2)CH(2))4P][CH(3)SO(3)] + 1-butanol, or 1-hexanol, 1-octanol, 1-decanol, or 1-dodecanol} and {[(CH(3)CH(2)CH(2)CH(2))4P][CH(3)SO(3)] + benzene, or toluene, ethylbenzene, or propylbenzene} have been measured by a dynamic method at a wide range of temperatures from 220 to 386 K. Solid-liquid equilibria with immiscibility in the liquid phase were detected with the aromatic hydrocarbons ethylbenzene and propylbenzene. The basic thermodynamic properties of pure ionic liquid--the melting point, enthalpy of fusion, enthalpy of solid-solid-phase transition, and glass transition--have been determined by differential scanning calorimetry. The experimental data of systems with alcohols were correlated by means of the UNIQUAC ASM and NRTL1 equations and of systems with alkylbenzenes with Wilson and NRTL equations utilizing parameters derived from the (solid + liquid) equilibrium. The root-mean-square deviations of the solubility temperatures for all calculated data are dependent upon the particular system and the particular equation used.

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Liquid-liquid equilibria for methanol + n-alkanes (C 9 to C 12 ) were determined in the temperature range (278.15 to 308.15 K), using a visual static method. Densities, refractive indices, and speeds of sound were also measured at 288.15, 298.15, and 308.15 K for acetone + n-alkane mixtures and at 298.15 and 308.15 K for methanol + n-alkane mixtures to study the temperature influence on mixing phenomena. The results were used to model liquid-liquid coexistence and derived properties trend. The calculated values based on the UNIQUAC equation were found to be similar to those based on the NRTL model. The Prigogine-Flory-Paterson theory was applied to estimate the excess molar volumes and the UNIFAC group contribution model for phase equilibria.

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