Improvements of COSMO-SAC for vapor–liquid and liquid–liquid equilibrium predictions

Hsieh, Chang-Tai; Sandler, Stanley I.; Lin, Shiang‐Tai

doi:10.1016/j.fluid.2010.06.011

Cited by 254 publications

(336 citation statements)

References 43 publications

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“…The hydrogen bonding contribution has been widely studied in the literature and various formulations have been proposed (e.g. Wang et al, 2007;Hsieh et al, 2010). Unfortunately, no COSMO-based formulation currently available can properly describe the complexity of hydrogen bonding in a general way.…”

Section: Brazilian Journal Of Chemical Engineeringmentioning

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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Section: Brazilian Journal Of Chemical Engineeringmentioning

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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“…34 Some improvements can therefore be made (to achieve a better description of the mutual solubilities between water and ILs), such as by changing the IL-water hydrogen-bonding energies. 35 Fig. 2b), and which are below the detection limit of the conductivity-based methodology used in this work.…”

Section: Cosmo-rs Partial Charge and Charge Distributionmentioning

confidence: 70%

Mutual solubilities between water and non-aromatic sulfonium-, ammonium- and phosphonium-hydrophobic ionic liquids

Kurnia

Quental

Santos

et al. 2015

Phys. Chem. Chem. Phys.

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Although previous studies attempted to characterize the liquid-liquid phase behaviour between water and ionic liquids (ILs), the impact of non-cyclic cations on the solubilities is poorly studied and yet to be understood. In this work, the mutual solubilities between water and ILs containing the anion bis (trifluoromethylsulfonyl) . The COSMO-RS is able to correctly predict the experimental UCST behaviour and the cation impact on the immiscibility regimes observed. Natural Population Analysis (NPA) calculations were additionally performed for the isolated cations in the gas phase indicating that the differences in the water-IL mutual miscibilities might not result only from the hydrophobicity of the cation (derived from the increase of the alkyl chains length) but also from the charge distribution of the central atom and attached methylene groups. This fact explains the enhanced solubility of ammonium-based ILs in water here identified.

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“…Better agreement with the experimental data is obtained for the more "hydrophobic" ILs, i.e., for those with longer alkyl side chains. This might result from an overestimation by the model of the hydrogen bond strength between water and the ILs [34,41]. Nevertheless, it should be highlighted that the COSMO-RS model is able to describe the decreasing saturation values of the solubility of water in ILs, and the increase of immiscibility gap, with increasing alkyl chain lengths experimentally observed.…”

Section: Resultsmentioning

confidence: 95%

Comprehensive study on the impact of the cation alkyl side chain length on the solubility of water in ionic liquids

Kurnia

Neves

Freire

et al. 2015

Journal of Molecular Liquids

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A comprehensive study on the phase behaviour of two sets of ionic liquids (ILs) and their interactions with water is here presented through combining experimental and theoretical approaches. The impact of the alkyl side chain length and the cation symmetry on the water solubility in the To complement the experimental data and to further investigate the molecular-level mechanisms behind the dissolution process, Density Functional Theory calculations, using the Conductor-like Screening Model for Real Solvents (COSMO-RS) and the Electrostatic potential-derived CHelpG, were performed. The COSMO-RS model is able to qualitatively predict water solubility as function of temperature and alkyl chain lengths of both symmetric and asymmetric cations. Furthermore, the model is also capable to predict the somewhat higher water solubility in the asymmetric cation, as well as the trend shift as function of alkyl chain lengths experimentally observed. Both COSMO-RS and the electrostatic potential-derived CHelpG show that the interactions of water and the IL cation take place on the IL polar region, namely on the aromatic head and adjacent methylene groups what explains the differences in water solubility observed for cations with different chain lengths. Furthermore, the CHelpG calculations for the isolated cations in the gas phase indicates that the trend shift of water solubility as function of alkyl chain lengths and the difference of water solubility in symmetric may also result from the partial positive charge distribution/contribution of the cation.

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Improvements of COSMO-SAC for vapor–liquid and liquid–liquid equilibrium predictions

Cited by 254 publications

References 43 publications

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

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

Mutual solubilities between water and non-aromatic sulfonium-, ammonium- and phosphonium-hydrophobic ionic liquids

Comprehensive study on the impact of the cation alkyl side chain length on the solubility of water in ionic liquids

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