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.

This work presents experimental data for the model system refined rice bran oil + commercial oleic acid + ethanol + water at 298.2 K. These data were correlated by the NRTL and UNIQUAC models, with a global deviation of approximately 0.7% for both models. The equilibrium of crude rice bran oil + aqueous ethanol was predicted with success using the adjusted interaction parameters, with deviation between calculated and experimental results not higher than 0.54%. The results showed that the addition of water to the solvent increases the solvent selectivity, reducing the losses of neutral oil and nutraceutical compounds, and expands the region of phase splitting, allowing the refining of highly acidic crude rice bran oils by solvent extraction.

In the present work, a group contribution model is proposed for estimating the dynamic viscosity of fatty compounds. For the major components involved in the vegetable oil industry (such as fatty acids, esters and alcohols, triacylglycerols, and partial acylglycerols), the optimized parameters are reported. In order to improve the data bank gathered from the literature, viscosity data were measured as a function of temperature for three saturated and three unsaturated fatty esters, one unsaturated fatty acid, and one unsaturated triacylglycerol. These last two are unavailable data in the literature (linolenic acid and trilinolenin). A simple method of calculation is also proposed to predict the dynamic viscosity of vegetable oils as an extended applicability of our equation. The model can be a valuable tool for designing processes and equipment for the oil industry, including edible and non-edible compounds, such as biodiesel.

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