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.

Recent experimental studies on noncatalytic transesterification have shown that high reaction rates, which justify the commercial application of this process, can be obtained if the operating conditions are above the critical pressure and temperature of methanol. Although it is generally agreed that temperatures of >550 K and high methanol/oil ratios are required to obtain high conversions and high reaction rates, there is disagreement in the literature regarding the operating pressure, the assumed phase conditions, the use of co-solvents, and the justification of the sudden increase of rate of reaction with temperature. In the present work, the reactor phase transitions are directly observed in a double-windowed cylindrical reactor and the conversion to methyl esters is measured. From direct observations and the modeling of the phase behavior, a better understanding of the supercritical methanol transesterification process is obtained.

Solubility data in water of ethane, propane, isobutane, n-butane, n-pentane, and n-hexane have been obtained as a function of temperature in vapor−liquid−liquid equilibrium (VLLE) conditions. The minimum temperature of experiments is 288 K, while the maximum temperature, for each system, is lower than the critical temperature of the corresponding hydrocarbon. New solubility vs temperature correlations are given herein for the studied hydrocarbons in water. Henry's law and activity coefficients at infinite dilution are deduced from the experimental solubility data. Good agreement is found with available literature data.

In the present work, the transesterification of non-edible oil with methanol and ethanol is studied. The reactor phase transitions are directly observed in a double windowed cylindrical reactor and the conversion to fatty esters is measured. The optimization of the process conditions was carried out based on a statistical design of experiments where the key process variables were studied over different ranges to obtain a reliable model for the efficiency of the reaction as a function of reaction time, temperature, pressure and alcohol to oil molar ratio. From direct observations and the modeling of the phase behavior, a better understanding of the supercritical alcohol transesterification process is obtained as well as the confirmation of the phase equilibrium predictions based on the GCA-EOS model.

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The densities of reacting mixtures of vegetable oils + methanol were measured by loading a closed vessel with a known amount of an oil/alcohol mixture of a given molar ratio. For each studied condition, the mixture was brought to a temperature at which the system became homogeneous. The isochoric (constant-volume) relation between temperature and pressure at this particular density and composition was recorded. In the temperature range of 550−630 K, a high conversion of the oil to the corresponding fatty esters and glycerin was obtained. The densities of sunflower oil with methanol for two different alcohol/oil ratios, namely, 40:1 and 25:1, were measured. Densities of coconut oil + methanol and methyl oleate + methanol mixtures were also measured. The effect of global density on conversion was studied at long reaction times (3−4 h). Strong evidence of the phase transitions of the reacting mixtures, from heterogeneous to homogeneous, was obtained from the experimental results.

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