Vegetable oils can be deacidified by liquid-liquid extraction. The difference in polarity between the triglycerides, the principal components of the oil, and the solvent guarantees the formation of two phases and permits the removal of free fatty acids. A knowledge of the equilibrium between the phases of such systems is important, however, if adequate equipment for the implementation of the process is to be designed. The present paper establishes experimental data for systems of canola oil, oleic acid, and alcohols, subsequently adjusting the NRTL and UNIQUAC models to them for the calculation of activity coefficients. The results show the good descriptive quality of the models.

The equations of the method based on the maximum likelihood principle have been rewritten in a suitable generalized form to allow the use of any number of implicit constraints in the determination of model parameters from experimental data and from the associated experimental uncertainties. In addition to the use of any number of constraints, this method also allows data, with different numbers of constraints, to be reduced simultaneously. Application of the method is illustrated in the reduction of liquid-liquid equilibrium data of binary, ternary and quaternary systems simultaneousl

Group interaction parameters for the UNIFAC and ASOG models were specially adjusted for predicting liquid−liquid equilibrium (LLE) for systems of vegetable oils, fatty acids, and ethanol at temperatures ranging from 20 to 45 °C. Experimental liquid−liquid equilibrium data for systems of triolein, oleic acid, and ethanol and of triolein, stearic acid, and ethanol were measured and utilized in the adjustment. The average percent deviation between experimental and calculated compositions was 0.79% and 0.52% for the UNIFAC and ASOG models, respectively. The prediction of liquid−liquid equilibrium for systems of vegetable oils, fatty acids, and ethanol was quite successful, with an average deviation of 1.31% and 1.32% for the UNIFAC and ASOG models, respectively.

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