The objective of this work was to determine liquid-liquid equilibrium data at (298.3 ( 0.2) K for systems of interest in biodiesel production, such systems being composed of vegetable oils + anhydrous ethanol + hexane. The measurements were performed using near-infrared spectroscopy (NIR) for quantification of the phases in equilibrium. The following vegetables oils were investigated: pretreated cottonseed oil, corn oil, canola oil, refined soybean oil, and degummed soybean oil. Initially, with the purpose of validating the NIR methodology, equilibrium data for the system composed of pretreated cottonseed oil (neutral) + commercial linoleic acid + anhydrous ethanol were determined at (298.2 ( 0.1) K by a conventional method based on acid-base titration and solvent evaporation and by the NIR method. The relative errors between the phase compositions determined by both analytical methods were 2.1 % for the alcoholic phase and 2.0 % for the oil phase. The mass balance errors for all investigated systems varied in the range from 0.03 % to 0.16 %, which indicates the good quality of the experimental data and the good performance of the NIR method. The experimental data were correlated using the NRTL model with an average global deviation of 0.70 %.

This study presents liquid−liquid equilibrium data for systems of interest in biodiesel production and the refining of edible oils by liquid−liquid extraction. These systems are composed of vegetable oils + anhydrous ethanol + water, at temperatures ranging from (298.15 to 333.15) K. The following vegetable oils were investigated: refined canola oil, refined corn oil, semiprocessed Jatropha curcas oil, and semiprocessed macauba (Acrocomia aculeata) pulp oil. According to the results, the enhancement of temperature within the study ranges increased oil−solvent miscibility in both phases. The liquid−liquid equilibrium experimental data were correlated using the non-random two liquid (NRTL) model. For all of these systems, the global deviations between calculated and experimental data were lower than 0.7 %, showing the good descriptive quality and applicability of the NRTL model in liquid−liquid analysis and computational simulation processes.

The aim of this work was to determine liquid−liquid equilibrium data for systems of interest in ethyl ester (biodiesel) production. The following systems were investigated: refined soybean oil + anhydrous ethanol + hexane at (313.15 ± 0.1) K and (328.25 ± 0.1) K, refined canola oil + anhydrous ethanol + hexane at (313.25 ± 0.1) K and (328.15 ± 0.1) K, and refined palm oil + anhydrous ethanol + hexane at (318.15 ± 0.1) K and (328.25 ± 0.1) K. The instrumental technique of near-infrared spectroscopy allied to multivariate calibration (in this work, this union was denominated “NIR method”) was used for quantification of the phase compositions. The NIR method presented an appropriate experimental accuracy for quantifying equilibrium data at higher temperatures. Good reliability of the phase compositions was confirmed from values of global mass balance deviations ranging from (0.06 to 0.16) %. The experimental data were correlated using the NRTL model with an average global deviation of 0.83 %.

-The aim of this work is to report the experimental data and thermodynamic modeling of phase equilibrium of binary systems containing soybean and olive oils with propane and n-butane. Phase equilibrium experiments were carried out using the static synthetic method in a high-pressure variable-volume view cell in the temperature range from 30 to 70 o C and varying the solvent overall composition from 5 to 98 wt%. Vapor-liquid, liquid-liquid and vapor-liquid-liquid phase transitions were observed at relatively low pressures. The Peng-Robinson and the SAFT equations of state without any binary interaction parameters were employed in an attempt at representing the phase behavior of the systems. Results show the satisfactory performance of SAFT-EoS in predicting qualitatively all phase transitions reported in this work.

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The objective of this work was to determine liquid−liquid equilibrium data for fatty systems of interest in the extraction/refining process of vegetable oils and in the biodiesel production. The following systems were investigated: refined rice bran oil + anhydrous ethanol + hexane at (298.15 ± 0.2) K and (313.15 ± 0.2) K and refined rice bran oil + commercial oleic acid + anhydrous ethanol + hexane at (298.15 ± 0.2) K with mass fractions of (5.08, 7.98, 10.65, and 15.09) % of fatty acid in oil. The instrumental technique of near-infrared spectroscopy allied to multivariate calibration (in this work, termed “NIR method”) was used for quantification of the phase compositions. For the pseudoternary system, the relative deviations for global mass balance were (0.10 and 0.11) % for the temperature of (298.15 and 313.15) K, respectively. For the pseudoquaternary systems, the relative deviations for global mass balance varied in the range from (0.15 to 0.31) %. The experimental data were correlated using the NRTL model with overall deviations lower than 1.15 %. We can conclude that the NIR method is highly accurate, and the low deviations obtained indicate the good quality of the equilibrium data.

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