Excess Molar Volumes of Mixtures of Hexane + Natural Oils from 298.15 to 313.15 K

González, Cristina; Resa, José M.; Ruiz, and Aitor; Gutiérrez, José Ignacio Puebla

doi:10.1021/je960308z

Cited by 15 publications

(21 citation statements)

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“…The variation of the refractive index of the mixtures with mole fraction of acetate at 298.15 K appears in Figure 3. The excess volume data and the variation of the refractive index were correlated as a function of composition using a Redlich-Kister expansion: [2] where x 1 and x 2 are the mole fractions of the higher-and lowervolatility compounds, respectively, and a k are the adjustable parameters obtained by the least squares method. Table 2 summarizes the values of the parameters a k together with the standard deviations (σ) of the differences between experimental values and those calculated from Equation 2.…”

Section: Resultsmentioning

confidence: 99%

“…This work is part of a more extensive investigation on mixing properties of organic solvents with edible oils (1)(2)(3)(4)(5)(6)(7). Here, excess molar volumes, refractive indices, and variations of the refractive indices at different temperatures (between 288.15 and 298.15 K) of alkyl acetates (ethyl, propyl, isopropyl, and butyl acetate) and vinyl acetate in mixtures with sunflower oil are shown.…”

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Excess molar volumes and refractive indices of mixtures formed by acetates with sunflower oil at different temperatures

González

Resa

Lanz

et al. 2002

J Americ Oil Chem Soc

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The aim of this work is to measure the densities and refractive indices of mixtures formed of acetates (ethyl, vinyl, propyl, isopropyl, and butyl acetate) with sunflower oil. From these measurements, excess molar volumes and variations of the refractive index of the mixtures have been calculated. The properties were measured at temperatures varying from 288.15 to 298.15 K. The excess molar volumes and variations of refractive index data were correlated vs. composition with RedlichKister polynomials. Densities of the mixtures were predicted by the Rackett and modified Rackett equations. Refractive indices of the mixtures were predicted by several mixing rules and compared with experimental values. In all cases, SD between predicted and experimental data were less than 5%.

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

Excess molar volumes and refractive indices of mixtures formed by acetates with sunflower oil at different temperatures

González

Resa

Lanz

et al. 2002

J Americ Oil Chem Soc

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“…Before introducing the oil in the column, FA were converted into methyl esters by sodium methanoate and extracted with hexane. The chromatographic technique and the chemical procedure for the preparation of FA were described in a previous work (2). The uncertainty in mol% for these results was less than 0.1%.…”

Section: Methodsmentioning

confidence: 93%

“…Experimental enthalpies of mixing were calculated from the electrical power as P el = V·I in which V is the measured potential difference and I is the current through the Ni-Cr wire. An enthalpy balance could be set up for the solution in the vessel during an experiment, ∆H/∆t = P el [1] with ∆H = m c pm ∆T [2] in which c pm is the heat capacity of the mixture at constant pressure. These equations can be used to calculate the heat capacity from the experimental data.…”

Section: Methodsmentioning

confidence: 99%

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Experimental and predicted enthalpies of mixing of mixtures formed from alcohols and sunflower oil at 298.15 K

González

Piñeiro

Resa

et al. 2005

J Americ Oil Chem Soc

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The enthalpies of mixing of systems formed from alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol) and sunflower oil at 298.15 K are presented. Enthalpies were measured in the composition range in which the compounds were miscible. From the experimental measurements, we calculated the heat capacities of the mixtures. Several group contribution models were applied to estimate the enthalpies of mixing of these mixtures. The average deviations varied from 10 to 60%, depending on the model and compound. The best prediction in all cases was the Nitta model, with average deviations from 10 to 30%. The novelty of the work is that models of this type have not been applied previously to predict enthalpies of such large molecules, and the results of the estimates are of the same order as other types of compounds (pure compounds of small size).Recently, we have been interested mainly in studying the mixing properties of mixtures involving organic solvents with vegetable oils (1-8). The present work is part of a series in which enthalpies of mixing of the mentioned compounds are measured. When experimental data are missing, group-contribution methods can be successfully applied to predict important properties such as enthalpies, vapor-liquid equilibria, and density. In groupcontribution methods, it is assumed that the mixture consists not of molecules but of functional groups. Different group-contribution methods, such as the analytical solution of groups (ASOG) (9) and universal quasi-chemical functional group activity coefficients (UNIFAC) (10), have been suggested. In both methods, the required activity coefficient is calculated by a combinatorial and a residual part. The UNIFAC method shows some weakness because poor results are obtained with compounds that are very different in size. To eliminate most of the mentioned weaknesses, some modifications of the UNIFAC method have been developed [see Dang and Tassios (10), Larsen et al. (11), and Weidlich and Gmehling (12)]. The UNIFAC group-contribution model was originally developed by Fredenslund et al. (13) using the universal quasi-chemical (UNIQUAC) equation by Abrams and Prausnitz (14). The activity coefficients in this model are calculated as the addition of two terms. The first one is combinatorial and takes into account the differences in shape and size of the molecules. The second one is a residual term describing the energetic interactions present in the mixture. The adjustable parameters in this model are the energetic interaction parameters between groups. Dang and Tassios (10) modified the original model, and their version is focused only on excess molar enthalpy estimations. In the version of Larsen et al. (11), the interaction parameters become temperature dependent, and the combinatorial term is modified. As a result, this version can predict other properties, such as Gibbs potential and phase equilibria. Weidlich and Gmehling (12) also modified the temperature dependence of the parameters, recalculated interaction parameters usi...

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Densities and Refractive Indices of Binary Mixtures of Olive Oil + Alkanols at 298.15 K

El‐Hefnawy

2013

J Solution Chem

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Excess Molar Volumes of Mixtures of Hexane + Natural Oils from 298.15 to 313.15 K

Cited by 15 publications

References 1 publication

Excess molar volumes and refractive indices of mixtures formed by acetates with sunflower oil at different temperatures

Excess molar volumes and refractive indices of mixtures formed by acetates with sunflower oil at different temperatures

Experimental and predicted enthalpies of mixing of mixtures formed from alcohols and sunflower oil at 298.15 K

Densities and Refractive Indices of Binary Mixtures of Olive Oil + Alkanols at 298.15 K

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