Modeling of Liquids Behavior: Experiments, Theory and Simulations

A special issue of Liquids (ISSN 2673-8015). This special issue belongs to the section "Chemical Physics of Liquids".

Deadline for manuscript submissions: closed (30 November 2022) | Viewed by 23523

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Division of Thermal Engineering and Instrumentation, University of Las Palmas de Gran Canaria, 35017-Las Palmas de Gran Canaria, Canary Islands, Spain
Interests: thermodynamic modeling; EoS; simulation of chemical engineering processes; properties of liquid solutions; behavior of pure liquid and solutions
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Special Issue Information

Dear Colleagues,

This Special Issue is focused on theoretical and applied research related to the behavior of both pure liquid and mixtures of organic and inorganic materials. Authors may consider a wide range of pure fluids and solutions with: polar and non-polar substances, polymers, surfactants, ionic liquids and complex and biological molecules. In general, papers describing novel instrumentation, new experimental methods and techniques, original experimental data on thermophysical properties, phase equilibria, modeling and correlation are welcome. Particular attention will be given to research on molecular thermodynamics providing quantitative estimates of liquid systems’ properties, as required for this process. Likewise, papers on models applied to processes such as conventional and supercritical extraction, fractionation, purification, etc., will also be considered.

This Special Issue will act as an international forum for researchers, summarizing the most recent developments and ideas in the field, with a special emphasis on the latest technical and theoretical results. Potential topics include, but are not limited to:

  • Measurements, data quality assessment and correlation of liquid properties;
  • Modeling of the behavior of pure components and liquid mixtures;
  • Theory and applications concerning liquid behavior;
  • Equations for states applied for the prediction of interfacial and/or equilibrium properties of pure fluids and heterogeneous mixtures;
  • Thermodynamic description of phase equilibrium phenomena;
  • Molecular design of co-solvents;
  • Separation process simulations and optimization using modeling;
  • Others relevant topics.

Prof. Dr. William E. Acree, Jr.
Prof. Dr. Juan Ortega Saavedra
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Liquids is an international peer-reviewed open access quarterly journal published by MDPI.

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Keywords

  • liquids
  • modeling
  • volumetric properties
  • molecular interactions
  • phase equilibria

Published Papers (14 papers)

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Research

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24 pages, 1178 KiB  
Article
Linear Solvation–Energy Relationships (LSER) and Equation-of-State Thermodynamics: On the Extraction of Thermodynamic Information from the LSER Database
by Costas Panayiotou, Ioannis Zuburtikudis, Hadil Abu Khalifeh and Vassily Hatzimanikatis
Liquids 2023, 3(1), 66-89; https://doi.org/10.3390/liquids3010007 - 11 Jan 2023
Cited by 4 | Viewed by 2026
Abstract
There is a remarkable wealth of thermodynamic information in freely accessible databases, the LSER database being a classical example. The LSER, or Abraham solvation parameter model, is a very successful predictive tool in a variety of applications in the (bio)chemical and environmental sector. [...] Read more.
There is a remarkable wealth of thermodynamic information in freely accessible databases, the LSER database being a classical example. The LSER, or Abraham solvation parameter model, is a very successful predictive tool in a variety of applications in the (bio)chemical and environmental sector. The model and the associated database are very rich in thermodynamic information and information on intermolecular interactions, which, if extracted properly, would be particularly useful in various thermodynamic developments for further applications. Partial Solvation Parameters (PSP), based on equation-of-state thermodynamics, are designed as a versatile tool that would facilitate this extraction of information. The present work explores the possibilities of such an LSER–PSP interconnection and the challenging issues this effort is faced with. The thermodynamic basis of the very linearity of the LSER model is examined, especially, with respect to the contribution of strong specific interactions in the solute/solvent system. This is done by combining the equation-of-state solvation thermodynamics with the statistical thermodynamics of hydrogen bonding. It is verified that there is, indeed, a thermodynamic basis of the LFER linearity. Besides the provenance of the sought linearity, an insight is gained on the thermodynamic character and content of coefficients and terms of the LSER linearity equations. The perspectives from this insight for the further development of LSER and related databases are discussed. The thermodynamic LSER–PSP interconnection is examined as a model for the exchange in information between QSPR-type databases and equation-of-state developments and the associated challenges are examined with representative calculations. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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9 pages, 4020 KiB  
Communication
Density and Dynamic Viscosity of Perfluorodecalin-Added n-Hexane Mixtures: Deciphering the Role of Fluorous Liquids
by Deepika and Siddharth Pandey
Liquids 2023, 3(1), 48-56; https://doi.org/10.3390/liquids3010005 - 04 Jan 2023
Cited by 5 | Viewed by 1886
Abstract
Fluorous solvents are deputed as prominent solvent systems owing to their salient features, unique physical properties, and ecological importance. In this study, the temperature- and composition-dependence of physical properties, density (ρ/g·cm−3), and dynamic viscosity (η/mPa·s), of neat [...] Read more.
Fluorous solvents are deputed as prominent solvent systems owing to their salient features, unique physical properties, and ecological importance. In this study, the temperature- and composition-dependence of physical properties, density (ρ/g·cm−3), and dynamic viscosity (η/mPa·s), of neat perfluorodecalin (PFD) and PFD-added n-hexane mixtures with select compositions are reported. Density follows a linear decrease with temperature and a quadratic increase with the mole fraction of PFD. The sensitivity or dependence of density on temperature increases with an increase in PFD mole fraction. The temperature-dependence of the dynamic viscosity of the investigated mixtures follows the Arrhenius-type expression from which the resultant activation energy of the viscous flow (Ea,η) is determined. Interestingly, the composition-dependence of dynamic viscosity shows exponential growth with an increase in PFD mole fraction. Excess molar volumes (VE) and deviation in the logarithmic viscosities ∆(ln η) of the mixtures are calculated to highlight the presence of strong repulsive interactions between the two mixture components. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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12 pages, 463 KiB  
Article
Thermodynamic Analysis of the Solubility of Sulfadiazine in (Acetonitrile 1-Propanol) Cosolvent Mixtures from 278.15 K to 318.15 K
by Carlos Francisco Trujillo-Trujillo, Fredy Angarita-Reina, Mauricio Herrera, Claudia Patria Ortiz, Rossember Edén Cardenas-Torres, Fleming Martinez and Daniel Ricardo Delgado
Liquids 2023, 3(1), 7-18; https://doi.org/10.3390/liquids3010002 - 22 Dec 2022
Cited by 2 | Viewed by 1587
Abstract
Drug solubility is one of the most significant physicochemical properties as it is related to drug design, formulation, quantification, recrystallization, and other processes, so understanding it is crucial for the pharmaceutical industry. In this context, this research presents the thermodynamic analysis of the [...] Read more.
Drug solubility is one of the most significant physicochemical properties as it is related to drug design, formulation, quantification, recrystallization, and other processes, so understanding it is crucial for the pharmaceutical industry. In this context, this research presents the thermodynamic analysis of the solubility of sulfadiazine (SD) in cosolvent mixtures {acetonitrile + 1-propanol} at 9 temperatures (278.15 K–318.15 K), which is a widely used drug in veterinary therapy, and two solvents of high relevance in the pharmaceutical industry, respectively. The solubility of SD, in cosolvent mixtures {acetonitrile + 1-propanol} is an endothermic process where the maximum solubility was reached in pure acetonitrile at 318.15 K and the minimum in 1-propanol at 278.15 K. Although the solubility parameters of acetonitrile and propanol were similar, the addition of acetonitrile to the cosolvent mixture leads to a positive cosolvent effect on the solubility of DS. As for the thermodynamic functions of the solution, the process is strongly influenced by enthalpy, and according to the enthalpy–entropy compensation analysis, the process is enthalpy-driven in intermediate to rich mixtures in 1-propanol and entropy-driven in mixtures rich in acetonitrile. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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6 pages, 429 KiB  
Article
Application of Solution Calorimetry to Determining the Fusion Enthalpy of an Arylaliphatic Compound at 298.15 K: n-Octadecanophenone
by Mikhail I. Yagofarov, Ilya S. Balakhontsev, Andrey A. Sokolov and Boris N. Solomonov
Liquids 2023, 3(1), 1-6; https://doi.org/10.3390/liquids3010001 - 21 Dec 2022
Viewed by 1493
Abstract
Evaluating the temperature dependence of the fusion enthalpy is no trivial task, as any compound melts at a unique temperature. At the same time, knowledge of the fusion enthalpies under some common conditions, particularly at the reference temperature of 298.15 K, would substantially [...] Read more.
Evaluating the temperature dependence of the fusion enthalpy is no trivial task, as any compound melts at a unique temperature. At the same time, knowledge of the fusion enthalpies under some common conditions, particularly at the reference temperature of 298.15 K, would substantially facilitate the comparative analysis and development of the predictive schemes. In this work, we continue our investigations of the temperature dependence of the fusion enthalpy of organic non-electrolytes using solution calorimetry. As an object of study, n-octadecanophenone, an arylaliphatic compound was chosen. The solvent appropriate for evaluating the fusion enthalpy at 298.15 K from the solution enthalpy of crystal was selected: p-xylene. The heat capacity and fusion enthalpy at the melting temperature were measured by differential scanning calorimetry to derive the fusion enthalpy at 298.15 K from the Kirchhoff’s law of Thermochemistry. An agreement between the independently determined values was demonstrated. This particular result opens a perspective for further studies of the fusion thermochemistry of arylaliphatic compounds at 298.15 K by solution calorimetry. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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13 pages, 1861 KiB  
Article
Density and Refractive Index of Binary Ionic Liquid Mixtures with Common Cations/Anions, along with ANFIS Modelling
by G. Reza Vakili-Nezhaad, Morteza Mohammadzaheri, Farzaneh Mohammadi and Mohammed Humaid
Liquids 2022, 2(4), 432-444; https://doi.org/10.3390/liquids2040025 - 05 Dec 2022
Cited by 1 | Viewed by 1497
Abstract
Ionic liquids have many interesting properties as they share the properties of molten salts as well as organic liquids, such as low volatility, thermal stability, electrical conductivity, non-flammability, and much more. Ionic liquids are known to be good solvents for many polar and [...] Read more.
Ionic liquids have many interesting properties as they share the properties of molten salts as well as organic liquids, such as low volatility, thermal stability, electrical conductivity, non-flammability, and much more. Ionic liquids are known to be good solvents for many polar and nonpolar solutes. Combined with their special properties, ionic liquids are good replacements for the conventional toxic and volatile organic solvents. Each ionic liquid has different properties than others. In order to alter, tune, and enhance the properties of ionic liquids, sometimes, it is necessary to mix different ionic liquids to achieve the desired properties. However, using mixtures of ionic liquids in chemical processes requires reliable estimations of the mixtures’ physical properties such as refractive index and density. The ionic liquids used in this work are 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([HMIM][BF4]), and 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF6]). These ionic liquids were supplied by Io-li-tec and used as received. However, new measurements for the density and refractive index were taken for the pure ionic liquids to be used as reference. In the present work, the densities and refractive indices of four different binary mixtures of ionic liquids with common cations and/or anions have been measured at various compositions and room conditions. The accuracy of different empirical mixing rules for calculation of the mixtures refractive indices was also studied. It was found that the overall absolute average percentage deviation from the ideal solution in the calculation of the molar volume of the examined binary mixtures was 0.78%. Furthermore, all of the examined mixing rules for the calculation of the refractive indices of the mixtures were found to be accurate. However, the most accurate empirical formula was found to be Heller’s relation, with an average percentage error of 0.24%. Furthermore, an artificial intelligence model, an adaptive neuro-fuzzy inference system (ANFIS), was developed to predict the density and refractive index of the different mixtures studied in this work as well as the published literature data. The predictions of the developed model were analyzed by various methods including both statistical and graphical approaches. The obtained results show that the developed model accurately predicts the density and refractive index with overall R2, RMSE, and AARD% values of 0.968, 7.274, 0.368% and 0.948, 7.32 × 10−3 and 0.319%, respectively, for the external validation dataset. Finally, a variance-based global sensitivity analysis was formed using extended the Fourier amplitude sensitivity test (EFAST). Our modelling showed that the ANFIS model outperforms the best available empirical models in the literature for predicting the refractive index of the different mixtures of ionic liquids. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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19 pages, 13348 KiB  
Article
Using Two Group-Contribution Methods to Calculate Properties of Liquid Compounds Involved in the Cyclohexanone Production Operations
by Luis Fernández, Juan Ortega, Leandro Domínguez, David Lorenzo, Aurora Santos and Arturo Romero
Liquids 2022, 2(4), 413-431; https://doi.org/10.3390/liquids2040024 - 23 Nov 2022
Cited by 1 | Viewed by 1714
Abstract
A numerical application has been carried out to determine the thermophysical properties of more than fifty pure liquid compounds involved in the production process of cyclohexanone, whose real values are unknown, in many cases. Two group-contribution methods, the Joback and the Marrero–Gani methods, [...] Read more.
A numerical application has been carried out to determine the thermophysical properties of more than fifty pure liquid compounds involved in the production process of cyclohexanone, whose real values are unknown, in many cases. Two group-contribution methods, the Joback and the Marrero–Gani methods, both used in the fields of physicochemistry and engineering, are employed. Both methods were implemented to evaluate critical properties, phase transition properties, and others, which are required for their use in industrial process simulation/design. The quality of the estimates is evaluated by comparing them with those from the literature, where available. In general, both models provide acceptable predictions, although each of them shows improvement for some of the properties considered, recommending their use, when required. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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9 pages, 1098 KiB  
Article
The Solubility of Ethyl Candesartan in Mono Solvents and Investigation of Intermolecular Interactions
by Cunbin Du
Liquids 2022, 2(4), 404-412; https://doi.org/10.3390/liquids2040023 - 17 Nov 2022
Cited by 1 | Viewed by 991
Abstract
In this work, the experimental solubility of ethyl candesartan in the selected solvents within the temperature ranging from 278.15 to 318.15 K was studied. It can be easily found that the solubility of ethyl candesartan increases with the rising temperature in all solvents. [...] Read more.
In this work, the experimental solubility of ethyl candesartan in the selected solvents within the temperature ranging from 278.15 to 318.15 K was studied. It can be easily found that the solubility of ethyl candesartan increases with the rising temperature in all solvents. The maximum solubility value was obtained in N,N-dimethylformamide (DMF, 7.91 × 10−2), followed by cyclohexanone (2.810 × 10−2), 1,4-dioxanone (2.69 × 10−2), acetone (7.04 × 10−3), ethyl acetate (4.20 × 10−3), n-propanol (3.69 × 10−3), isobutanol (3.38 × 10−3), methanol (3.17 × 10−3), n-butanol (3.03 × 10−3), ethanol (2.83 × 10−3), isopropanol (2.69 × 10−3), and acetonitrile (1.15 × 10−2) at the temperature of 318.15 K. Similar results of solubility sequence from large to small were also obtained in other temperatures. The X-ray diffraction analysis illustrates that the crystalline forms of all samples were consistent, and no crystalline transformation occurred during the dissolution process. In aprotic solvents, except for individual solvents, the solubility data decreases with the decreasing values of hydrogen bond basicity (β) and dipolarity/polarizability (π*). The largest average relative deviation (ARD) data in the modified Apelblat equation is 1.9% and observed in isopropanol; the maximum data in λh equation is 4.3% and found in n-butanol. The results of statistical analysis show that the modified Apelblat equation is the more suitable correlation of experimental data for ethyl candesartan in selected mono solvents at all investigated temperatures. In addition, different parameters were used to quantify the solute–solvent interactions that occurred in the dissolution process including Abraham solvation parameters (APi), Hansen solubility parameters (HPi), and Catalan parameters (CPi). Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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10 pages, 519 KiB  
Article
Correlation of Surface Tension of Mono-Solvents at Various Temperatures
by Navid Kabudi, Ali Shayanfar, William E. Acree, Jr. and Abolghasem Jouyban
Liquids 2022, 2(4), 378-387; https://doi.org/10.3390/liquids2040021 - 26 Oct 2022
Cited by 2 | Viewed by 2038
Abstract
Surface tension is among the most important factors in chemical and pharmaceutical processes. Modeling the surface tension of solvents at different temperatures helps to optimize the type of solvent and temperature. The surface tension of solvents at different temperatures with their solvation parameters [...] Read more.
Surface tension is among the most important factors in chemical and pharmaceutical processes. Modeling the surface tension of solvents at different temperatures helps to optimize the type of solvent and temperature. The surface tension of solvents at different temperatures with their solvation parameters was used in this study to develop a model based on the van’t Hoff equation by multiple linear regression. Abraham solvation parameters, Hansen solubility parameters, and Catalan parameters are among the most discriminating descriptors. The overall MPD of the model was 3.48%, with a minimum and maximum MPD of 0.04% and 11.62%, respectively. The model proposed in this study could be useful for predicting the surface tension of mono-solvents at different temperatures. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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51 pages, 1405 KiB  
Article
Revision and Extension of a Generally Applicable Group Additivity Method for the Calculation of the Refractivity and Polarizability of Organic Molecules at 298.15 K
by Rudolf Naef and William E. Acree, Jr.
Liquids 2022, 2(4), 327-377; https://doi.org/10.3390/liquids2040020 - 13 Oct 2022
Cited by 3 | Viewed by 1659
Abstract
In a continuation and extension of an earlier publication, the calculation of the refractivity and polarizability of organic molecules at standard conditions is presented, applying a commonly applicable computer algorithm based on an atom group additivity method, where the molecules are broken down [...] Read more.
In a continuation and extension of an earlier publication, the calculation of the refractivity and polarizability of organic molecules at standard conditions is presented, applying a commonly applicable computer algorithm based on an atom group additivity method, where the molecules are broken down into their constituting atoms, these again being further characterized by their immediate neighbor atoms. The calculation of their group contributions, carried out by means of a fast Gauss–Seidel fitting calculus, used the experimental data of 5988 molecules from literature. An immediate subsequent ten-fold cross-validation test confirmed the extraordinary accuracy of the prediction of the molar refractivity, indicated by a correlation coefficient R2 and a cross-validated analog Q2 of 0.9997, a standard deviation σ of 0.38, a cross-validated analog S of 0.41, and a mean absolute deviation of 0.76%. The high reliability of the predictions was exemplified with three classes of molecules: ionic liquids and silicon- and boron-containing compounds. The corresponding molecular polarizabilities were calculated indirectly from the refractivity using the inverse Lorentz–Lorenz relation. In addition, it could be shown that there is a close relationship between the “true” volume and the refractivity of a molecule, revealing an excellent correlation coefficient R2 of 0.9645 and a mean absolute deviation of 7.53%. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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9 pages, 481 KiB  
Article
Estimating Equivalent Alkane Carbon Number Using Abraham Solute Parameters
by William E. Acree, Jr., Wei-Khiong Chong, Andrew S.I.D. Lang and Hamed Mozafari
Liquids 2022, 2(4), 318-326; https://doi.org/10.3390/liquids2040019 - 02 Oct 2022
Cited by 2 | Viewed by 1406
Abstract
The use of equivalent alkane carbon numbers (EACN) to characterize oils is important in surfactant-oil-water (SOW) systems. However, the measurement of EACN values is non-trivial and thus it becomes desirable to predict EACN values from structure. In this work, we present a simple [...] Read more.
The use of equivalent alkane carbon numbers (EACN) to characterize oils is important in surfactant-oil-water (SOW) systems. However, the measurement of EACN values is non-trivial and thus it becomes desirable to predict EACN values from structure. In this work, we present a simple linear model that can be used to estimate the EACN value of oils with known Abraham solute parameters. We used linear regression with leave-one-out cross validation on a dataset of N = 80 oils with known Abraham solute parameters to derive a general model that can reliably estimate EACN values based upon the Abraham solute parameters: E (the measured liquid or gas molar refraction at 20 °C minus that of a hypothetical alkane of identical volume), S (dipolarity/polarizability), A (hydrogen bond acidity), B (hydrogen bond basicity), and V (McGowan characteristic volume) with good accuracy within the chemical space studied (N = 80, R2 = 0.92, RMSE = 1.16, MAE = 0.90, p < 2.2 × 10−16). These parameters are consistent with those in other models found in the literature and are available for a wide range of compounds. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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31 pages, 2181 KiB  
Article
Development of Abraham Model Correlations for Solute Transfer into the tert-Butyl Acetate Mono-Solvent and Updated Equations for Both Ethyl Acetate and Butyl Acetate
by Laine Longacre, Emily Wu, Chelsea Yang, Miles Zhang, Sneha Sinha, Advika Varadharajan and William E. Acree, Jr.
Liquids 2022, 2(4), 258-288; https://doi.org/10.3390/liquids2040016 - 22 Sep 2022
Cited by 9 | Viewed by 1459
Abstract
Experimental solubilities were determined for 31 solid nonelectrolyte organic compounds dissolved in tert-butyl acetate at 298.15 K. Results of the experimental measurements were combined with published mole fraction solubility data for two lipid-lowering medicinal compounds (lovastatin and simvastatin) in order to derive [...] Read more.
Experimental solubilities were determined for 31 solid nonelectrolyte organic compounds dissolved in tert-butyl acetate at 298.15 K. Results of the experimental measurements were combined with published mole fraction solubility data for two lipid-lowering medicinal compounds (lovastatin and simvastatin) in order to derive Abraham model expressions for solute transfer into the tert-butyl acetate mono-solvent. The derived correlations provided an accurate mathematical description of the observed experimental data. As part of the current study, previously published Abraham model solvent correlations for both ethyl acetate and butyl acetate were updated using much larger datasets that contained an additional 64 and 35 experimental data points, respectively. The mathematical correlations presented in the current study describe the observed solubility ratios of solutes dissolved in tert-butyl acetate, ethyl acetate, and butyl acetate to within an overall standard deviation of 0.15 log units or less. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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22 pages, 2454 KiB  
Article
Increasing the Equilibrium Solubility of Meloxicam in Aqueous Media by Using Dimethyl Sulfoxide as a Cosolvent: Correlation, Dissolution Thermodynamics and Preferential Solvation
by Darío A. Tinjacá, Fleming Martínez, Ovidio A. Almanza, M. Ángeles Peña, Abolghasem Jouyban and William E. Acree, Jr.
Liquids 2022, 2(3), 161-182; https://doi.org/10.3390/liquids2030011 - 12 Aug 2022
Cited by 4 | Viewed by 1786
Abstract
Meloxicam is widely prescribed as an analgesic and anti-inflammatory drug in human therapeutics. Owing the very low aqueous solubility of meloxicam, this property has been studied in dimethyl sulfoxide (DMSO)-aqueous solvent systems at several temperatures from 273.15 to 313.15 K to expand the [...] Read more.
Meloxicam is widely prescribed as an analgesic and anti-inflammatory drug in human therapeutics. Owing the very low aqueous solubility of meloxicam, this property has been studied in dimethyl sulfoxide (DMSO)-aqueous solvent systems at several temperatures from 273.15 to 313.15 K to expand the solubility database about analgesic drugs in mixed solvents. The flask shake method followed by ultraviolet-visible (UV-vis) spectrophotometry analysis were used for meloxicam solubility determinations. A number of cosolvency models, including the Jouyban–Acree model, were challenged for solubility correlation/prediction of this drug in these mixtures. The van’t Hoff and Gibbs equations were employed to calculate the apparent standard thermodynamic quantities relative to dissolution and mixing processes. The inverse Kirkwood–Buff integral method was employed for calculating the preferential solvation parameters of meloxicam by DMSO in the mixtures. Meloxicam solubility increases with increasing temperature and maximum solubilities are observed in neat DMSO at all temperatures studied. Dissolution processes were endothermic in all cases and entropy-driven in the composition interval of 0.40 ≤ x1 ≤ 1.00. A nonlinear enthalpy–entropy relationship was observed in the plot of enthalpy vs. Gibbs energy for drug transfer processes. Meloxicam is preferentially solvated by water in water-rich mixtures but preferentially solvated by DMSO in the composition interval of 0.21 < x1 < 1.00. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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Review

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9 pages, 628 KiB  
Review
The Relevance of Cavity Creation for Several Phenomena Occurring in Water
by Giuseppe Graziano
Liquids 2023, 3(1), 57-65; https://doi.org/10.3390/liquids3010006 - 09 Jan 2023
Cited by 1 | Viewed by 1488
Abstract
The solvent-excluded volume effect is an under-appreciated general phenomenon occurring in liquids and playing a fundamental role in many cases. It is quantified and characterized by means of the theoretical concept of cavity creation and its Gibbs free energy cost. The magnitude of [...] Read more.
The solvent-excluded volume effect is an under-appreciated general phenomenon occurring in liquids and playing a fundamental role in many cases. It is quantified and characterized by means of the theoretical concept of cavity creation and its Gibbs free energy cost. The magnitude of the reversible work of cavity creation proves to be particularly large in water, and this fact plays a key role for, among other things, the poor solubility of nonpolar species, the formation of host–guest complexes, and the folding of globular proteins. An analysis of some examples is provided in the present review. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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15 pages, 2269 KiB  
Review
Thermodynamic Modeling of Mineral Scaling in High-Temperature and High-Pressure Aqueous Environments
by Derek M. Hall, Serguei N. Lvov and Isaac K. Gamwo
Liquids 2022, 2(4), 303-317; https://doi.org/10.3390/liquids2040018 - 28 Sep 2022
Cited by 1 | Viewed by 1399
Abstract
Methods of predicting mineral scale formation have evolved over the years from simple empirical fittings to sophisticated computational programs. Though best practices can now solve complex multi-phase, multi-component systems, they are largely restricted to temperatures below 300 °C. This review examines critical gaps [...] Read more.
Methods of predicting mineral scale formation have evolved over the years from simple empirical fittings to sophisticated computational programs. Though best practices can now solve complex multi-phase, multi-component systems, they are largely restricted to temperatures below 300 °C. This review examines critical gaps in existing mineral scale modeling approaches as well as strategies to overcome them. Above 300 °C, the most widely used model of standard thermodynamic functions for aqueous species fails when fluid densities are below 0.7 g cm−3. This failure occurs due to the model’s reliance on an empirical form of the Born equation which is unable to capture the trends observed in these high temperature, low density regimes. However, new models based on molecular solvent-solute interactions offer a pathway to overcome some of the deficiencies currently limiting high-temperature and high-pressure mineral scale predictions. Examples of the most common scale prediction methods are presented, and their advantages and disadvantages are discussed. Full article
(This article belongs to the Special Issue Modeling of Liquids Behavior: Experiments, Theory and Simulations)
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