A modified UNIFAC model. 2. Present parameter matrix and results for different thermodynamic properties

Gmehling, Juergen; Li, Jiding; Schiller, Martin

doi:10.1021/ie00013a024

Cited by 1,313 publications

(1,353 citation statements)

References 7 publications

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“…Computational methods as COSMO-RS [31], SPARC [32], UNIFAC [33] and EPI Suite [34], were tested in order to predict or estimate the solubility of the studied terpenes in water [35]. However, as can be seen in Table 3, none of them was able to predict satisfactorily the solubility values, nor even the solubility ranking among the different compounds The expanded uncertainty for a 95% confidence interval is presented between brackets.…”

Section: Aqueous Solubilitiesmentioning

confidence: 99%

Terpenes solubility in water and their environmental distribution

Martins

Silva

Ferreira

et al. 2017

Journal of Molecular Liquids

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Terpenes and terpenoids belong to the largest and most diverse class of natural products. Due to the increasing importance of their applications and the emerging perception of their impact on the environment, the available physico-chemical characterization is insufficient. In this work the water solubility of geraniol, linalool, DL-citronellol, thymol, eugenol, carvacrol and p-cymene, in the temperature range from (298.15 to 323.15) K, and at atmospheric pressure, is studied. Due to the low solubility of these compounds a novel technique was adopted for their measurements and validated using the aqueous solubility data for sparingly soluble aromatic compounds. The thermodynamic properties of solution were derived from the experimental data at infinite dilution. It is shown that the solubility of terpenes in water is an endothermic process confirming the existence of UCST phase diagrams, and only for carvacrol and eugenol is entropically driven. The experimental information is shown in a two-dimensional chemical space diagram providing indications to their probable distribution in the environment once released.

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Section: Aqueous Solubilitiesmentioning

confidence: 99%

Terpenes solubility in water and their environmental distribution

Martins

Silva

Ferreira

et al. 2017

Journal of Molecular Liquids

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“…This package contains a modified UNIFAC (Gmehling et al, 1993) implementation with the parameter matrix published by Jakob et al (2006). Three parameters are used for the temperature-dependent term mn Ψ :…”

Section: Unifacmentioning

confidence: 99%

Assessing the reliability of predictive activity coefficient models for molecules consisting of several functional groups

Gerber

Soares

2013

Braz. J. Chem. Eng.

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-Currently, the most successful predictive models for activity coefficients are those based on functional groups such as UNIFAC. In contrast, these models require a large amount of experimental data for the determination of their parameter matrix. A more recent alternative is the models based on COSMO, for which only a small set of universal parameters must be calibrated. In this work, a recalibrated COSMO-SAC model was compared with the UNIFAC (Do) model employing experimental infinite dilution activity coefficient data for 2236 non-hydrogen-bonding binary mixtures at different temperatures. As expected, UNIFAC (Do) presented better overall performance, with a mean absolute error of 0.12 ln-units against 0.22 for our COSMO-SAC implementation. However, in cases involving molecules with several functional groups or when functional groups appear in an unusual way, the deviation for UNIFAC was 0.44 as opposed to 0.20 for COSMO-SAC. These results show that COSMO-SAC provides more reliable predictions for multifunctional or more complex molecules, reaffirming its future prospects.

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“…In the present work, solid-liquid equilibrium data on two fatty mixtures, triolein + 1-octadecanol and triolein + 1-hexadecanol, were measured by differential scanning calorimetry (DSC), evaluated with optical microscopy and modeled by resolution of the thermodynamic equilibrium equations using the twoand three-suffix Margules equations, the original UNIFAC (Fredenslund et al, 1975) and the modified UNIFAC-Dortmund model (Gmehling et al, 1993) for calculation of the liquid-phase activity coefficient. An optimization algorithm was implemented in MATLAB for prediction of the melting point.…”

Section: Brazilian Journal Of Chemical Engineeringmentioning

confidence: 99%

“…T is the temperature (K). In this work, in addition to the original UNIFAC model, the modified UNIFACDortmund model (Gmehling et al, 1993) was also used. In this model, the combinatorial term C i γ (Equation (18)) was empirically changed to make it possible to deal with compounds that are very different in size.…”

Section: Thermodynamic Frameworkmentioning

confidence: 99%

Solid-liquid equilibrium of triolein with fatty alcohols

Máximo

Costa

Meirelles

2013

Braz. J. Chem. Eng.

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-Triacylglycerols and fatty alcohols are used in the formulation of cosmetic, pharmaceutical and food products. Although information about the phase transitions of these compounds and their mixtures is frequently required for design and optimization of processes and product formulation involving these substances, these data are still scarce in the literature. In the present study, the solid-liquid phase diagrams of two binary systems composed of triolein + 1-hexadecanol and triolein + 1-octadecanol were evaluated by differential scanning calorimetry (DSC) and optical microscopy. The experimental data were compared with predicted data by solving the phase equilibrium equations using an algorithm implemented in MATLAB. The liquid-phase activity coefficients were calculated using the Margules equation (two-and three-suffix) and the UNIFAC model (original and modified Dortmund model). The approaches used for calculating system equilibrium allowed an accurate prediction of the liquidus line with low deviations from the experimental data.

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A modified UNIFAC model. 2. Present parameter matrix and results for different thermodynamic properties

Cited by 1,313 publications

References 7 publications

Terpenes solubility in water and their environmental distribution

Terpenes solubility in water and their environmental distribution

Assessing the reliability of predictive activity coefficient models for molecules consisting of several functional groups

Solid-liquid equilibrium of triolein with fatty alcohols

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