Pub Date : 2026-06-01Epub Date: 2026-02-02DOI: 10.1016/j.fluid.2026.114690
Karel Šindelka , Karel Aim , Martin Lísal
Active Brownian particles (ABPs) serve as a versatile model for synthetic active matter, such as self-propelled colloids, combining persistent propulsion with Brownian motion. When confined, ABPs exhibit propulsion-induced wall accumulation, a phenomena that can be exploited in microfluidics and lab-on-a-chip applications. In addition, at high confined densities and particle activities, ABPs display distinct structural phenomena, including confined and surface motility-induced phase separations (MIPSs). Confined MIPS manifests as the coexistence of solid-like and dense phases, whereas surface MIPS involves the emergence of high-density clustering structures near the confining walls. The formation of these solid-like and high-density clustering-structure states along with their structures is further influenced by wall roughness. We investigate ABPs in slit pores using overdamped Langevin dynamics simulations at a liquid particle density and a particle activity exceeding the bulk MIPS threshold. We examine their wall accumulation and MIPS behavior as functions of slit width and wall roughness. Furthermore, we contrast these confined ABPs with their equilibrium counterparts, confined fluid particles capable of completely wetting the slit walls.
{"title":"Motility-induced phase separations in confined active particle systems","authors":"Karel Šindelka , Karel Aim , Martin Lísal","doi":"10.1016/j.fluid.2026.114690","DOIUrl":"10.1016/j.fluid.2026.114690","url":null,"abstract":"<div><div>Active Brownian particles (ABPs) serve as a versatile model for synthetic active matter, such as self-propelled colloids, combining persistent propulsion with Brownian motion. When confined, ABPs exhibit propulsion-induced wall accumulation, a phenomena that can be exploited in microfluidics and lab-on-a-chip applications. In addition, at high confined densities and particle activities, ABPs display distinct structural phenomena, including confined and surface motility-induced phase separations (MIPSs). Confined MIPS manifests as the coexistence of solid-like and dense phases, whereas surface MIPS involves the emergence of high-density clustering structures near the confining walls. The formation of these solid-like and high-density clustering-structure states along with their structures is further influenced by wall roughness. We investigate ABPs in slit pores using overdamped Langevin dynamics simulations at a liquid particle density and a particle activity exceeding the bulk MIPS threshold. We examine their wall accumulation and MIPS behavior as functions of slit width and wall roughness. Furthermore, we contrast these confined ABPs with their equilibrium counterparts, confined fluid particles capable of completely wetting the slit walls.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114690"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-19DOI: 10.1016/j.fluid.2026.114675
Wen Hwa Siah, Marco Campestrini, Paolo Stringari
A precise understanding of the solubility limits of solids in methane-rich mixtures is essential for assessing crystallization risks in the production of liquefied natural gas (LNG). While recent studies have provided new experimental data and modelling approaches dealing with the solubility of heavy components (primarily aromatic compounds) in binary mixtures with methane, the phase equilibrium behavior of multi-component mixtures at cryogenic temperatures remains insufficiently understood.
Given its high solubility in methane, the presence of neopentane in the feed mixture may potentially reduce the crystallization risk of other heavy components (i.e., chemicals having a triple-point temperature above the LNG temperature like carbon dioxide), either by enhancing their solubility at specific temperature and pressure conditions or by extending the pressure range over which the fluid phase remains stable.
This study presents new insights into the thermodynamic behavior of systems comprised of methane, carbon dioxide, and neopentane, with the aim of investigating the effect of neopentane on the solubility of carbon dioxide in methane. New experimental data were determined for: (1) the binary carbon dioxide + neopentane system, including both liquid-vapor equilibrium (VLE) and solid-fluid equilibrium (SFE) measurements down to 170 K, and (2) the ternary methane + carbon dioxide + neopentane system, with SFE measurements down to 120 K. Both systems were studied using two different static-analytic apparatuses.
The experimental results were compared with modelling results obtained by coupling the Peng-Robinson Equation of State (PR78 EoS) for the fluid phases with the Classical Approach for the solid phases.
{"title":"Solid-fluid equilibria of mixtures of interest in LNG production: Measurement and modelling of methane + carbon dioxide + neo-pentane systems","authors":"Wen Hwa Siah, Marco Campestrini, Paolo Stringari","doi":"10.1016/j.fluid.2026.114675","DOIUrl":"10.1016/j.fluid.2026.114675","url":null,"abstract":"<div><div>A precise understanding of the solubility limits of solids in methane-rich mixtures is essential for assessing crystallization risks in the production of liquefied natural gas (LNG). While recent studies have provided new experimental data and modelling approaches dealing with the solubility of heavy components (primarily aromatic compounds) in binary mixtures with methane, the phase equilibrium behavior of multi-component mixtures at cryogenic temperatures remains insufficiently understood.</div><div>Given its high solubility in methane, the presence of neopentane in the feed mixture may potentially reduce the crystallization risk of other heavy components (i.e., chemicals having a triple-point temperature above the LNG temperature like carbon dioxide), either by enhancing their solubility at specific temperature and pressure conditions or by extending the pressure range over which the fluid phase remains stable.</div><div>This study presents new insights into the thermodynamic behavior of systems comprised of methane, carbon dioxide, and neopentane, with the aim of investigating the effect of neopentane on the solubility of carbon dioxide in methane. New experimental data were determined for: (1) the binary carbon dioxide + neopentane system, including both liquid-vapor equilibrium (VLE) and solid-fluid equilibrium (SFE) measurements down to 170 K, and (2) the ternary methane + carbon dioxide + neopentane system, with SFE measurements down to 120 K. Both systems were studied using two different static-analytic apparatuses.</div><div>The experimental results were compared with modelling results obtained by coupling the Peng-Robinson Equation of State (PR78 EoS) for the fluid phases with the Classical Approach for the solid phases.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114675"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-19DOI: 10.1016/j.fluid.2026.114674
Shuo Wang , Jingjing Zhou , Jingjian Li , Yanmin Song , Bowen Zhang , Dandan Han , Junbo Gong
As a key intermediate in the synthesis of anticancer agents, 5′-O-Dimethoxytrityl-N-benzoyl-deoxycytidine (Bz-Dmt-dC) usually presents as a solvate and its purity plays a critical role in the production process. To obtain high purity products quickly and efficiently via crystallization, the solubility data of the compound must first be determined. Therefore, under the premise of ensuring no phase transitions during the measurement process, the solubility of solvates formed by Bz-Dmt-dC in three binary solvent systems (acetonitrile + water, acetone + water, and THF + water) were experimentally determined over the temperature range of 278.15 to 313.15 K at atmospheric pressure using the gravimetric method. The experimental results showed that, for a given solvent type and composition, the solubility of Bz-Dmt-dC increased with increasing temperature. The solubility data of Bz-Dmt-dC were correlated using the modified Apelblat, λh, and NRTL equations. Among these, the modified Apelblat model provided the best fitting result, as indicated by the lowest average relative deviation (ARD) values of 0.7%.
5′- o -二甲氧基三烷基- n -苯甲酰脱氧胞苷（Bz-Dmt-dC）作为抗癌药物合成的关键中间体，通常以溶剂形式存在，其纯度在生产过程中起着至关重要的作用。为了通过结晶快速有效地获得高纯度产品，必须首先确定化合物的溶解度数据。因此，在保证测量过程无相变的前提下，在278.15 ~ 313.15 K的大气压温度范围内，用重量法实验测定了Bz-Dmt-dC形成的溶剂化物在乙腈+水、丙酮+水、THF +水三种二元溶剂体系中的溶解度。实验结果表明，在一定溶剂类型和组成下，Bz-Dmt-dC的溶解度随温度升高而增大。利用修正后的Apelblat、λh和NRTL方程对Bz-Dmt-dC的溶解度数据进行相关性分析。其中，修正Apelblat模型拟合效果最好，平均相对偏差（ARD）值最低，为0.7%。
{"title":"Solubility measurement and data correlation of 5′-O-Dimethoxytrityl-N-benzoyl-deoxycytidine solvate in three binary solvent systems from 278.15 to 313.15 K","authors":"Shuo Wang , Jingjing Zhou , Jingjian Li , Yanmin Song , Bowen Zhang , Dandan Han , Junbo Gong","doi":"10.1016/j.fluid.2026.114674","DOIUrl":"10.1016/j.fluid.2026.114674","url":null,"abstract":"<div><div>As a key intermediate in the synthesis of anticancer agents, 5′-O-Dimethoxytrityl-N-benzoyl-deoxycytidine (Bz-Dmt-dC) usually presents as a solvate and its purity plays a critical role in the production process. To obtain high purity products quickly and efficiently via crystallization, the solubility data of the compound must first be determined. Therefore, under the premise of ensuring no phase transitions during the measurement process, the solubility of solvates formed by Bz-Dmt-dC in three binary solvent systems (acetonitrile + water, acetone + water, and THF + water) were experimentally determined over the temperature range of 278.15 to 313.15 K at atmospheric pressure using the gravimetric method. The experimental results showed that, for a given solvent type and composition, the solubility of Bz-Dmt-dC increased with increasing temperature. The solubility data of Bz-Dmt-dC were correlated using the modified Apelblat, <em>λ</em>h, and NRTL equations. Among these, the modified Apelblat model provided the best fitting result, as indicated by the lowest average relative deviation (ARD) values of 0.7%.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114674"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-02-06DOI: 10.1016/j.fluid.2026.114695
Pengshuai Zhang, Binbin Wu, Jiaqi Sun, Yukun Liu, Lan Cui, Shuoye Yang
In this research, the solubility of indomethacin was measured in seven neat solvents {ethanol, ethyl acetate, acetonitrile, butyl acetate, isopropanol, anisole, and 1,4-dioxane} and two binary solvents (1,4-dioxane + acetonitrile and ethyl acetate + acetonitrile) using a laser dynamic monitoring method. The experimental conditions were 283.15–323.15 K under 0.1 MPa. To correlate the solubility data of indomethacin, four thermodynamic models were employed: the λh model, Yaws model, UNIQUAC model, and NRTL model. The results show that the Yaws model has the best correlation fitting effect than the other three models. Moreover, the solid-phase of indomethacin from the chosen solvents was characterized using the powder X-ray diffraction (PXRD) and the differential scanning calorimetry (DSC) technology. The solubility of indomethacin in the selected solvents was analyzed using Hansen solubility parameters (HSPs). Additionally, to determine the interaction sites of indomethacin in the solvents, the surface charge distribution of the indomethacin molecule was analyzed using molecular electrostatic potential surfaces (MEPS). Subsequently, based on the MEPS study, molecular dynamics simulations were further employed to investigate the interactions between solute and solvent molecules using the radial distribution function (RDF). Lastly, the apparent thermodynamic properties of indomethacin in the chosen solvents were determined via the apparent analysis approach. The results indicated that the dissolution process of indomethacin was endothermic and entropy-increasing. By comparing the values of ζH and ζTS, it was found that the ζH values are consistently greater than the ζTS values, indicating that enthalpy is the primary contributor to ΔsolG0 during the dissolution process.
{"title":"Revealing the dissolution mechanism of indomethacin (Form γ) in several neat and binary solvents based on experiments and molecular simulations","authors":"Pengshuai Zhang, Binbin Wu, Jiaqi Sun, Yukun Liu, Lan Cui, Shuoye Yang","doi":"10.1016/j.fluid.2026.114695","DOIUrl":"10.1016/j.fluid.2026.114695","url":null,"abstract":"<div><div>In this research, the solubility of indomethacin was measured in seven neat solvents {ethanol, ethyl acetate, acetonitrile, butyl acetate, isopropanol, anisole, and 1,4-dioxane} and two binary solvents (1,4-dioxane + acetonitrile and ethyl acetate + acetonitrile) using a laser dynamic monitoring method. The experimental conditions were 283.15–323.15 K under 0.1 MPa. To correlate the solubility data of indomethacin, four thermodynamic models were employed: the λh model, Yaws model, UNIQUAC model, and NRTL model. The results show that the Yaws model has the best correlation fitting effect than the other three models. Moreover, the solid-phase of indomethacin from the chosen solvents was characterized using the powder X-ray diffraction (PXRD) and the differential scanning calorimetry (DSC) technology. The solubility of indomethacin in the selected solvents was analyzed using Hansen solubility parameters (HSPs). Additionally, to determine the interaction sites of indomethacin in the solvents, the surface charge distribution of the indomethacin molecule was analyzed using molecular electrostatic potential surfaces (MEPS). Subsequently, based on the MEPS study, molecular dynamics simulations were further employed to investigate the interactions between solute and solvent molecules using the radial distribution function (RDF). Lastly, the apparent thermodynamic properties of indomethacin in the chosen solvents were determined via the apparent analysis approach. The results indicated that the dissolution process of indomethacin was endothermic and entropy-increasing. By comparing the values of <em>ζ<sub>H</sub></em> and <em>ζ<sub>TS</sub></em>, it was found that the <em>ζ<sub>H</sub></em> values are consistently greater than the <em>ζ<sub>TS</sub></em> values, indicating that enthalpy is the primary contributor to Δ<sub>sol</sub><em>G</em><sup>0</sup> during the dissolution process.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114695"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-22DOI: 10.1016/j.fluid.2026.114685
Mahdi Mansoury , Mohammad Ali Badamchizadeh , Peyman Roozafzoon Bashsiz , Sina Pakkhesal , Elaheh Rahimpour , Abolghasem Jouyban
Drug solubility is a critical physicochemical property in pharmaceutical research, governing drug formulation, therapeutic efficacy, and bioavailability. Conventional methods for solubility determination and prediction often rely on labor-intensive experimental approaches or computationally limited thermodynamic models. This study employs advanced machine learning and deep learning techniques to simulate the solubility of azole-based antifungal drugs in binary solvent systems at various temperatures, benchmarking their performance against traditional thermodynamic models. Experimental solubility data for ten azole drugs in various binary solvent mixtures were analyzed. Models evaluated included linear algorithms, tree-based methods, ensemble boosting techniques (XGBoost, LightGBM, CatBoost), kernel-based approaches (support vector regression, Gaussian process regression), and deep learning architectures (multilayer perceptrons, hybrid frameworks). The performances of the models were evaluated using mean relative deviation (MRD) as the primary performance metric. CatBoost (MRD = 6.9 %), the hybrid framework (MRD = 9.2 %), and XGBoost (MRD = 12.0 %) were identified as the top three models. In addition, their performances were comprehensively evaluated using a set of supplementary metrics to ensure robust comparative assessment. The findings highlight the superior predictive accuracy of data-driven algorithms, demonstrating their potential as robust tools for pharmaceutical development and the optimization of solvent systems.
{"title":"Evaluating machine learning models for accurate solubility prediction of azole drugs in binary solvents at various temperatures","authors":"Mahdi Mansoury , Mohammad Ali Badamchizadeh , Peyman Roozafzoon Bashsiz , Sina Pakkhesal , Elaheh Rahimpour , Abolghasem Jouyban","doi":"10.1016/j.fluid.2026.114685","DOIUrl":"10.1016/j.fluid.2026.114685","url":null,"abstract":"<div><div>Drug solubility is a critical physicochemical property in pharmaceutical research, governing drug formulation, therapeutic efficacy, and bioavailability. Conventional methods for solubility determination and prediction often rely on labor-intensive experimental approaches or computationally limited thermodynamic models. This study employs advanced machine learning and deep learning techniques to simulate the solubility of azole-based antifungal drugs in binary solvent systems at various temperatures, benchmarking their performance against traditional thermodynamic models. Experimental solubility data for ten azole drugs in various binary solvent mixtures were analyzed. Models evaluated included linear algorithms, tree-based methods, ensemble boosting techniques (XGBoost, LightGBM, CatBoost), kernel-based approaches (support vector regression, Gaussian process regression), and deep learning architectures (multilayer perceptrons, hybrid frameworks). The performances of the models were evaluated using mean relative deviation (MRD) as the primary performance metric. CatBoost (MRD = 6.9 %), the hybrid framework (MRD = 9.2 %), and XGBoost (MRD = 12.0 %) were identified as the top three models. In addition, their performances were comprehensively evaluated using a set of supplementary metrics to ensure robust comparative assessment. The findings highlight the superior predictive accuracy of data-driven algorithms, demonstrating their potential as robust tools for pharmaceutical development and the optimization of solvent systems.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114685"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-24DOI: 10.1016/j.fluid.2026.114684
Sebastián Echeverri Restrepo , Guillermo E. Morales-Espejel
Refrigerants are increasingly being used as lubricating media in high-pressure, high-temperature applications such as compressors, where accurate prediction of their thermophysical properties is essential for effective design and performance optimisation. In this study, we present a molecular dynamics framework to simulate the density and viscosity of a refrigerant across a wide range of conditions relevant to the contact between a rolling element and the raceway of a bearing in an compressor. Using both Non-Equilibrium (SLLOD) and Equilibrium Molecular Dynamics (Green–Kubo) approaches, we evaluate the performance of the OPLS force field and validate the use of atomic SLLOD equations for small refrigerant molecules (instead of the more complex molecular version). The simulation results show good agreement with literature data. We conclude that this methodology offers a reliable and computationally efficient tool for characterising refrigerants, even under extreme operating conditions.
{"title":"Density and viscosity of refrigerant R123 with OPLS force field and atomic SLLOD","authors":"Sebastián Echeverri Restrepo , Guillermo E. Morales-Espejel","doi":"10.1016/j.fluid.2026.114684","DOIUrl":"10.1016/j.fluid.2026.114684","url":null,"abstract":"<div><div>Refrigerants are increasingly being used as lubricating media in high-pressure, high-temperature applications such as compressors, where accurate prediction of their thermophysical properties is essential for effective design and performance optimisation. In this study, we present a molecular dynamics framework to simulate the density and viscosity of a refrigerant across a wide range of conditions relevant to the contact between a rolling element and the raceway of a bearing in an compressor. Using both Non-Equilibrium (SLLOD) and Equilibrium Molecular Dynamics (Green–Kubo) approaches, we evaluate the performance of the OPLS force field and validate the use of <em>atomic</em> SLLOD equations for small refrigerant molecules (instead of the more complex <em>molecular</em> version). The simulation results show good agreement with literature data. We conclude that this methodology offers a reliable and computationally efficient tool for characterising refrigerants, even under extreme operating conditions.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114684"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146090663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-02-07DOI: 10.1016/j.fluid.2026.114694
Dhoni Hartanto , Boelo Schuur , Anton A. Kiss , André B. de Haan
In extractive distillation for the separation of azeotropic mixtures, eco-friendly solvents have demonstrated potential as greener alternatives to conventional entrainers. However, the absence of thermodynamic data for mixtures that include green solvents presents a significant hurdle to their practical application. This work explores, for the first time, vapor-liquid equilibrium (VLE) data for the azeotropic mixture of n-hexane and ethanol in the presence of the biobased entrainers guaiacol and dimethyl isosorbide (DMI). The VLE measurements were conducted using a Fischer Labodest VLE 502 ebulliometer with varying pressures and entrainer-to-feed ratios (E/Fs). The VLE data met the criteria of the Van Ness method and thereby pass the thermodynamic consistency test. The results confirm that the relative volatility of n-hexane to ethanol is increased by the addition of guaiacol and DMI to the mixture. Moreover, the azeotrope has been successfully removed. The VLE data were well regressed using the Non-Random Two Liquid (NRTL) thermodynamic model, which provided accurate binary interaction parameters (BIPs). The thermodynamic modeling verifies the reliability of the experimental data and its relevance for effective process design, emphasizing the viability of guaiacol and DMI as biobased entrainers for more sustainable and greener extractive distillation.
{"title":"Vapor-liquid equilibrium for the separation of the n-hexane + ethanol azeotropic mixture with biobased entrainers guaiacol and dimethyl isosorbide","authors":"Dhoni Hartanto , Boelo Schuur , Anton A. Kiss , André B. de Haan","doi":"10.1016/j.fluid.2026.114694","DOIUrl":"10.1016/j.fluid.2026.114694","url":null,"abstract":"<div><div>In extractive distillation for the separation of azeotropic mixtures, eco-friendly solvents have demonstrated potential as greener alternatives to conventional entrainers. However, the absence of thermodynamic data for mixtures that include green solvents presents a significant hurdle to their practical application. This work explores, for the first time, vapor-liquid equilibrium (VLE) data for the azeotropic mixture of n-hexane and ethanol in the presence of the biobased entrainers guaiacol and dimethyl isosorbide (DMI). The VLE measurements were conducted using a Fischer Labodest VLE 502 ebulliometer with varying pressures and entrainer-to-feed ratios (E/Fs). The VLE data met the criteria of the Van Ness method and thereby pass the thermodynamic consistency test. The results confirm that the relative volatility of n-hexane to ethanol is increased by the addition of guaiacol and DMI to the mixture. Moreover, the azeotrope has been successfully removed. The VLE data were well regressed using the Non-Random Two Liquid (NRTL) thermodynamic model, which provided accurate binary interaction parameters (BIPs). The thermodynamic modeling verifies the reliability of the experimental data and its relevance for effective process design, emphasizing the viability of guaiacol and DMI as biobased entrainers for more sustainable and greener extractive distillation.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114694"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146184988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-10DOI: 10.1016/j.fluid.2026.114662
Ziyi Zhou, Nefeli Novak, Georgios M. Kontogeorgis, Xiaodong Liang
Electrolyte solutions are central to many industrial, geochemical, and biological processes, yet their thermodynamic modeling remains challenging. This work assesses the predictive performance of the eSAFT-VR Mie equation of state by focusing on two key modeling parameters: (i) the distance of closest approach, comparing the ion segment diameter () with the effective hard-sphere diameter (), and (ii) the choice of ion–ion combining rules, both dispersion-energy-based formulations, namely the Hudson–McCoubrey (CR1) and the modified Lennard-Jones (CR2) rules. Predictions of mean ionic activity coefficients (MIAC) and liquid densities were evaluated for 57 aqueous salts without additional parameter fitting. Results show that density is relatively insensitive to the choice of parameters, whereas MIAC exhibits salt- and concentration-dependent sensitivity, particularly for multivalent systems. The comparison of CR1 and CR2 highlights that no single combining rule performs universally best, with accuracy depending on the ion type and charge density. These findings provide guidance for selecting the parameters and improving predictive electrolyte models.
{"title":"Evaluation of the effect of segment diameter and combining rules in eSAFT-VR Mie modeling of aqueous electrolyte solutions","authors":"Ziyi Zhou, Nefeli Novak, Georgios M. Kontogeorgis, Xiaodong Liang","doi":"10.1016/j.fluid.2026.114662","DOIUrl":"10.1016/j.fluid.2026.114662","url":null,"abstract":"<div><div>Electrolyte solutions are central to many industrial, geochemical, and biological processes, yet their thermodynamic modeling remains challenging. This work assesses the predictive performance of the eSAFT-VR Mie equation of state by focusing on two key modeling parameters: (i) the distance of closest approach, comparing the ion segment diameter (<span><math><mi>σ</mi></math></span>) with the effective hard-sphere diameter (<span><math><mi>d</mi></math></span>), and (ii) the choice of ion–ion combining rules, both dispersion-energy-based formulations, namely the Hudson–McCoubrey (CR1) and the modified Lennard-Jones (CR2) rules. Predictions of mean ionic activity coefficients (MIAC) and liquid densities were evaluated for 57 aqueous salts without additional parameter fitting. Results show that density is relatively insensitive to the choice of parameters, whereas MIAC exhibits salt- and concentration-dependent sensitivity, particularly for multivalent systems. The comparison of CR1 and CR2 highlights that no single combining rule performs universally best, with accuracy depending on the ion type and charge density. These findings provide guidance for selecting the parameters and improving predictive electrolyte models.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114662"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recent publications have reported phase equilibrium data for CO₂ + methylcyclopentane (MCP) and CO2 + 2,2-dimethylbutane using static-analytical sampling methods that are inconsistent with previously published synthetic-method data. To verify the reliability of our earlier measurements, we have repeated vapor–liquid equilibrium (VLE) experiments for both CO₂ + MCP and CO₂ + 2,2-dimethylbutane in the range 20–90 °C using a high-pressure variable-volume PVT cell with visual observation. Our new data agree within 1–2 bar with the values previously reported by our group, confirming the reproducibility of the synthetic method. To further validate our methodology, we also investigated the CO₂ + toluene system, which has been extensively studied in the literature. Our experimental results are in agreement with reference data, thereby confirming the accuracy of the synthetic technique and of the procedures used for mixture preparation and bubble-point detection. These results support the conclusion that the discrepancies between our data and those obtained by static-analytical methods cannot be attributed to errors inherent to the synthetic technique.
{"title":"Validation of synthetic method for phase equilibria measurements: Re-examination of CO₂ + methylcyclopentane, CO₂ + 2,2-dimethylbutane, and benchmarking with CO₂ + toluene","authors":"Jean-Luc Daridon , Jean-Patrick Bazile , Jean-Noël Jaubert , Stéphane Vitu","doi":"10.1016/j.fluid.2026.114664","DOIUrl":"10.1016/j.fluid.2026.114664","url":null,"abstract":"<div><div>Recent publications have reported phase equilibrium data for CO₂ + methylcyclopentane (MCP) and CO<sub>2</sub> + 2,2-dimethylbutane using static-analytical sampling methods that are inconsistent with previously published synthetic-method data. To verify the reliability of our earlier measurements, we have repeated vapor–liquid equilibrium (VLE) experiments for both CO₂ + MCP and CO₂ + 2,2-dimethylbutane in the range 20–90 °C using a high-pressure variable-volume PVT cell with visual observation. Our new data agree within 1–2 bar with the values previously reported by our group, confirming the reproducibility of the synthetic method. To further validate our methodology, we also investigated the CO₂ + toluene system, which has been extensively studied in the literature. Our experimental results are in agreement with reference data, thereby confirming the accuracy of the synthetic technique and of the procedures used for mixture preparation and bubble-point detection. These results support the conclusion that the discrepancies between our data and those obtained by static-analytical methods cannot be attributed to errors inherent to the synthetic technique.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114664"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-08DOI: 10.1016/j.fluid.2026.114660
Neda Sanchouli , Chathura J. Kankanamge, Andreas P. Fröba, Thomas M. Koller
The present study investigates the surface tension and viscosity of carbon dioxide (CO2) in the vicinity of the critical point using molecular dynamics (MD) simulations and surface light scattering (SLS). The latter technique was applied to simultaneously obtain the sum of the dynamic shear viscosities of the liquid phase, ηL, and vapor phase, ηV, as well as the surface tension σ at macroscopic thermodynamic equilibrium at temperatures T from (283.15 to 303.65) K, corresponding to reduced temperatures TR from 0.931 to 0.998. The measurement results for (ηL + ηV) and σ with average expanded (k = 2) uncertainties of (2.4 and 2.6) % agree very well with the few data available in the literature. The T-dependent behavior of the SLS results for σ can be described by a van der Waals-type surface tension equation in accordance with scaling theory. The experimental results for σ of CO2 served to evaluate the performance of equilibrium molecular dynamics (EMD) simulations in predicting its surface tension together with the phase behavior at T between (288.15 and 298.15) K. For this purpose, seven different force fields (FFs) employed from literature were applied, which provide all-atom or united-atom representations and involve rigid or flexible intramolecular potentials. It was found that a reliable representation of the vapor and liquid densities, vapor pressure, and σ near the critical point can only be realized using rigid FFs, all of which were not optimized against surface tension data.
{"title":"Surface tension and viscosity of carbon dioxide near the critical point using molecular dynamics simulations and surface light scattering","authors":"Neda Sanchouli , Chathura J. Kankanamge, Andreas P. Fröba, Thomas M. Koller","doi":"10.1016/j.fluid.2026.114660","DOIUrl":"10.1016/j.fluid.2026.114660","url":null,"abstract":"<div><div>The present study investigates the surface tension and viscosity of carbon dioxide (CO<sub>2</sub>) in the vicinity of the critical point using molecular dynamics (MD) simulations and surface light scattering (SLS). The latter technique was applied to simultaneously obtain the sum of the dynamic shear viscosities of the liquid phase, <em>η</em><sub>L</sub>, and vapor phase, <em>η</em><sub>V</sub>, as well as the surface tension <em>σ</em> at macroscopic thermodynamic equilibrium at temperatures <em>T</em> from (283.15 to 303.65) K, corresponding to reduced temperatures <em>T</em><sub>R</sub> from 0.931 to 0.998. The measurement results for (<em>η</em><sub>L</sub> + <em>η</em><sub>V</sub>) and <em>σ</em> with average expanded (<em>k</em> = 2) uncertainties of (2.4 and 2.6) % agree very well with the few data available in the literature. The <em>T</em>-dependent behavior of the SLS results for <em>σ</em> can be described by a van der Waals-type surface tension equation in accordance with scaling theory. The experimental results for <em>σ</em> of CO<sub>2</sub> served to evaluate the performance of equilibrium molecular dynamics (EMD) simulations in predicting its surface tension together with the phase behavior at <em>T</em> between (288.15 and 298.15) K. For this purpose, seven different force fields (FFs) employed from literature were applied, which provide all-atom or united-atom representations and involve rigid or flexible intramolecular potentials. It was found that a reliable representation of the vapor and liquid densities, vapor pressure, and <em>σ</em> near the critical point can only be realized using rigid FFs, all of which were not optimized against surface tension data.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"605 ","pages":"Article 114660"},"PeriodicalIF":2.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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