Extension of the COSMO-UNIFAC Thermodynamic Model

Zhu, Ruisong; Taheri, Mohsen; Zhang, Jie; Lei, Zhigang

doi:10.1021/acs.iecr.9b05963

“…However, estimated infinite-dilution properties, aqueous solubilities of hydrocarbons, and excess heat capacities C E P of liquid mixtures are frequently not satisfactory [142]. Similar comments apply to COSMO-RS and related models [143][144][145][146][147].…”

Section: Property Changes On Mixing and Excess Propertiesmentioning

confidence: 73%

Solutions, in Particular Dilute Solutions of Nonelectrolytes: A Review

Wilhelm¹

2021

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The liquid state is one of the three principal states of matter and arguably the most important one; and liquid mixtures represent a large research field of profound theoretical and practical interest. This topic is of importance in many areas of the applied sciences, such as in chemical engineering, geochemistry, the environmental sciences, biophysics and biomedical technology. First, I will concisely present a review of important concepts from classical thermodynamics of nonelectrolyte solutions; this will be followed by a survey of (semi-)empirical approaches to representing the composition and temperature dependence of selected thermodynamic mixture properties, and finally the focus will be on dilute binary nonelectrolyte solutions where one component, a supercritical solute, is present in much smaller quantity than the other component, called the solvent. Partial molar properties in the limit of infinite dilution (indicated by a superscript ∞) are of particular interest. For instance, activity coefficients (Lewis–Randall (LR) convention) are customarily used to characterize mixing behavior, and infinite-dilution values $$\gamma_{i}^{{{\text{LR,}}\infty }}$$ γ i LR, ∞ provide a convenient route for obtaining binary parameters for several popular solution models. When discussing solute (j)—solvent (i) interactions in solutions where the solute is supercritical, the Henry fugacity $$h_{j,i} \left( {T,P} \right)$$ h j , i T , P , also known as Henry’s law (HL) constant, is a measurable thermodynamic key quantity. Its temperature dependence yields information on the partial molar enthalpy change on solution $$\Delta H_{j}^{\infty } \left( {T,P} \right)$$ Δ H j ∞ T , P , while its pressure dependence yields information on the partial molar volume $$V_{j}^{{{\text{L,}}\infty }} \left( {T,P} \right)$$ V j L, ∞ T , P of solute j in the liquid phase (superscript L). I will clarify issues frequently overlooked, touch upon solubility data reduction and correlation, report a few recent high-precision experimental results on dilute aqueous solutions of supercritical nonelectrolytes, and show the equivalency of results for caloric quantities (e.g. $$\Delta H_{j}^{\infty }$$ Δ H j ∞ ) obtained via van ’t Hoff analysis of high-precision solubility data with directly measured calorimetric data.

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“…Recently, our group proposed a united model, COSMO‐UNIFAC, 98–101 that extends the current UNIFAC model. The COSMO‐UNIFAC model is based on the original UNIFAC model, which is extended by regressing the IDACs obtained from COSMO‐based models to cover the binary group interaction parameters that are missing from the UNIFAC group matrix in the latest state (see Figure S1).…”

Section: Combined Models For Ilsmentioning

confidence: 99%

Predictive molecular thermodynamic models for ionic liquids

Yu

¹

,

Wei

²

,

Chen

³

et al. 2022

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Predictive molecular thermodynamic models can bridge the gap between the microscopic molecular level and macroscopic system scale. Over the past few decades, ionic liquids (ILs), as a class of green solvents and functional materials, have received widespread research interest in the field of chemical processing owing to their unique physicochemical merits. This review aims to provide an easy‐to‐read and exhaustive reference regarding state‐of‐the‐art predictive thermodynamic models for ILs, with more focuses on UNIFAC‐ and COSMO‐based models and various applications involving phase equilibrium prediction, guidance for IL screening and design, and building equilibrium stage models for separation processes. This review provides a theoretical perspective on the structure–property relationships between molecular structures and phase behaviors for the systems and the constituted components covering a multi‐scale viewpoint from molecular level to industrial scale. Moreover, the predictive capacities of different thermodynamic models are comprehensively compared.

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“…Nonetheless, some parameters are still missing from the parameter matrix. Recently, it has likewise been demonstrated how electronic structure calculations, specifically COSMO-based (conductor-like screening model) calculations, can be used to predict missing UNIFAC parameters [85][86][87]. While the SMx universal solvent models, MOSCED, and UNIFAC are all limited in the system they can treat, there is opportunity for synergy among the methods.…”

Section: Water Asmentioning

confidence: 99%

Assessment of the SM12, SM8, and SMD Solvation Models for Predicting Limiting Activity Coefficients at 298.15 K

Roese

¹

,

Heintz

²

,

Uzat

³

et al. 2020

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The SMx (x = 12, 8, or D) universal solvent models are implicit solvent models which using electronic structure calculations can compute solvation free energies at 298.15 K. While solvation free energy is an important thermophysical property, within the thermodynamic modeling of phase equilibrium, limiting (or infinite dilution) activity coefficients are preferred since they may be used to parameterize excess Gibbs free energy models to model phase equilibrium. Conveniently, the two quantities are related. Therefore the present study was performed to assess the ability to use the SMx universal solvent models to predict limiting activity coefficients. Two methods of calculating the limiting activity coefficient where compared: (1) the solvation free energy and self-solvation free energy were both predicted and (2) the self-solvation free energy was computed using readily available vapor pressure data. Overall the first method is preferred as it results in a cancellation of errors, specifically for the case in which water is a solute. The SM12 model was compared to both the Universal Quasichemical Functional-group Activity Coefficients (UNIFAC) and modified separation of cohesive energy density (MOSCED) models. MOSCED was the highest performer, yet had the smallest available compound inventory. UNIFAC and SM12 exhibited comparable performance. Therefore further exploration and research should be conducted into the viability of using the SMx models for phase equilibrium calculations.

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Extension of the COSMO-UNIFAC Thermodynamic Model

Cited by 41 publications

References 22 publications

Solutions, in Particular Dilute Solutions of Nonelectrolytes: A Review

Solutions, in Particular Dilute Solutions of Nonelectrolytes: A Review

Predictive molecular thermodynamic models for ionic liquids

Assessment of the SM12, SM8, and SMD Solvation Models for Predicting Limiting Activity Coefficients at 298.15 K

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