Fluid Phase Equilibria最新文献

{"title":"On dispersion and polar interactions and solvation and cohesion energies. A first round","authors":"W.E. Acree Jr ,&nbsp;C. Panayiotou","doi":"10.1016/j.fluid.2025.114573","DOIUrl":"10.1016/j.fluid.2025.114573","url":null,"abstract":"<div><div>Understanding the role of intermolecular interactions and their specific contributions to thermodynamic quantities remains one of the major goals of Molecular Thermodynamics. Numerous polarity scales and related divisions of intermolecular interactions have been proposed in the literature but the exchange of information between them is not always easy, causing often much confusion. The present work is part of a broader effort for the development of a solid thermodynamic framework for the reliable exchange of such information. The work is a continuation of our recent work on the prediction of the contribution of hydrogen-bonding interactions to solvation enthalpies and free-energies. It focuses on the rest of the contributions arising, primarily, from dispersion and polar interactions. The way these contributions are handled in the relevant literature are discussed. Emphasis is given on the QSPR (Quantitative Structure Property Relationships) - type approaches exemplified by the Linear Solvation Energy Relationship (LSER) approach. The results of two alternative LSER routes to the estimation of solvation enthalpies are critically evaluated and their limitations are discussed. Much emphasis is given on self-solvation, where the relations of solvation energies to cohesion energies, heats of vaporization and internal pressures are examined. Based on this evaluation, an effort is made to establish simple universal methods for the prediction of dispersion and polar contributions to solvation energies free, to a rather significant extent, from the above limitations. These new methods are using molecular descriptors based on quantum – chemical (QC) calculations and referred to as QC-LSER descriptors. The predictions are compared with experimental data and / or other predictive methods in literature. Extensive comparison with the original LSER calculations is made and reported in Supplementary Information file. The strengths, limitations and perspectives of the new approach are also discussed.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"600 ","pages":"Article 114573"},"PeriodicalIF":2.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144904187","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}

{"title":"Pressure and temperature dependent UNIQUAC model for methanol - water mixtures","authors":"Adina Werner ,&nbsp;Jongmin Kim ,&nbsp;Fabian Mauss","doi":"10.1016/j.fluid.2025.114533","DOIUrl":"10.1016/j.fluid.2025.114533","url":null,"abstract":"<div><div>A pressure dependency is included in a quadratic temperature dependent binary interaction parameter of the UNIQUAC model. The obtained activity coefficients for methanol-water mixtures are compared with only temperature dependent UNIQUAC and UNIFAC, and with calculated activity coefficients based on experimental data between 298.15 - 373.15 K and 0.1519 - 1.01325 bar produced with vapor-liquid equilibrium calculations and Wilson method. This model exhibits an overall good agreement. The predicted activity coefficients are more adaptable than those from models without pressure dependence, indicating potential for further improvement.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114533"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144712888","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}

{"title":"Experimental and theoretical study on ion association in [Hmim][halide] + methanol/dimethyl sulfoxide mixtures","authors":"Zhida Zuo ,&nbsp;Hui Wang ,&nbsp;Linghong Lu ,&nbsp;Xiaohua Lu ,&nbsp;Xiaoyan Ji","doi":"10.1016/j.fluid.2025.114571","DOIUrl":"10.1016/j.fluid.2025.114571","url":null,"abstract":"<div><div>The electrical conductivities of 1-hexyl-3-methylimidazolium halides ([Hmim][halide], halide = Cl^–, Br^–, I^–) were measured in methanol (MeOH) and dimethyl sulfoxide (DMSO) at dilute concentrations from 293.15 to 313.15 K, alongside liquid density measurements for parametrization. Molar conductivity (Λ) decreased with increasing IL concentration and decreasing temperature, with solvent effects predominating over those of anion size. Λ was higher in MeOH than in DMSO due to lower viscosity and greater ion dissociation of MeOH. Comparison with a previous study involving H₂O, MeOH, DMSO, and isopropanol confirmed that solvent viscosity is the dominant factor influencing Λ at infinite dilution. At higher IL concentrations, Λ in MeOH fell below that in H₂O, likely due to a reduced number of free ions and the formation of larger solvated ion complexes.</div><div>To analyze conductivity behavior, the Debye-Huckel-Onsager model was employed to determine the limiting molar conductivity (<em>Λ₀</em>), which was subsequently used in the Shedlovsky equation to calculate the association constant (<em>K_A</em>). For comparison, simultaneous regression of <em>Λ₀</em> and <em>K_A</em> was also performed. The results indicated that, within the same solvent, <em>Λ₀</em> increased with temperature, while <em>K_A</em> exhibited irregular trends. Across different solvents, <em>Λ₀</em> correlated with solvent viscosity, and <em>K_A</em> was influenced by dielectric constant and polarity. Solvent effects on both <em>Λ₀</em> and <em>K_A</em> were more pronounced than those of anion size, suggesting the dominant role of the solvent environment. Positive Eyring activation enthalpies showed the endothermic ion-pairing process. Additionally, the Walden product suggested stronger ion-solvent interactions and larger solvated ions in MeOH compared to DMSO. These findings provide deeper insight into IL conductivity in diverse solvent environments.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"600 ","pages":"Article 114571"},"PeriodicalIF":2.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144913458","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}

{"title":"A deep study on the phase behavior of the mixture CO2 – n-Hexadecane at 298.15 K: Miscibility window, mass barotropy, volumetric/saturation data, and separability of the phases","authors":"Danilo A Ribeiro ,&nbsp;Rafael M Charin ,&nbsp;Alexandre J M Vieira ,&nbsp;Krishnaswamy Rajagopal ,&nbsp;Juliana Boechat ,&nbsp;Ana B Foradini ,&nbsp;Ian Hovell ,&nbsp;Silvia Sebrão","doi":"10.1016/j.fluid.2025.114575","DOIUrl":"10.1016/j.fluid.2025.114575","url":null,"abstract":"<div><div>This paper investigates the phase behavior of the CO₂ - n-Hexadecane mixture at a temperature of 298.15 K for high CO₂ concentrations. Under these conditions, the systems exhibit liquid-liquid equilibria at high pressures, accompanied by interesting phenomena, including a miscibility window and mass barotropy. The idea was to scrutinize the phase behavior of a simple compositional system displaying intricacies inherent to more complex CO₂-dominant fluids. The literature gap addressed in this paper is the generated volumetric data, accompanied by a discussion of the results concerning the composition and density of the phases indirectly calculated using the volumetric method. The generated phase equilibrium (saturation and volumetric) and density data can be used in basic projects as a model mixture of CO₂-rich phases for feeding porous or pipe multi-phase flow software simulations. The present investigation observed the separability of the phases under different conditions. The results suggest that interfacial tension is the main factor determining the degree of separability between these high-pressure liquid phases. Slight differences in density display a secondary, less pronounced impact on dispersibility; however, the interface tends not to resolve when the densities are similar, resulting in large stationary drops in this region.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"600 ","pages":"Article 114575"},"PeriodicalIF":2.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144916914","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}

{"title":"Water content in pure CO2 and CO2-rich mixtures using the DSH analytical technique","authors":"Larissa F. Torres ,&nbsp;Antonin Chapoy ,&nbsp;Rod Burgass ,&nbsp;Cláudio Dariva ,&nbsp;Papa M. Ndiaye ,&nbsp;Frederico W. Tavares","doi":"10.1016/j.fluid.2025.114523","DOIUrl":"10.1016/j.fluid.2025.114523","url":null,"abstract":"<div><div>The accurate determination of water content in equilibrium with hydrates helps to prevent operational problems related to flow assurance, and it is essential for the emerging Carbon Capture and Storage (CCS) processes for decarbonization. However, the experimental challenges associated with these measurements cause a scarcity of data. The development of the Differential Scanning Hygrometer (DSH) method has increased the number of water content reports for CO₂-rich systems in equilibrium with hydrates. It monitors not absolute values but fluctuations in the water content due to the formation of ice or dew inside a temperature-controlled tube. Here, we provide experimental and modeling investigation for water content on pure CO₂ and two CO₂-rich mixtures (CO₂+CH₄ and CO₂+CH₄+N₂) in equilibrium with hydrates: the sCPA and the SRK+EMS equations of state were used to model the obtained experimental data, both using the van der Waals-Platteeuw (vdW-P) model for the hydrate phase.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114523"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144595438","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}

{"title":"Solving the UVN-flash problem in TVN-space","authors":"Pardeep Kumar ,&nbsp;Patricio I. Rosen Esquivel","doi":"10.1016/j.fluid.2025.114528","DOIUrl":"10.1016/j.fluid.2025.114528","url":null,"abstract":"<div><div>In this paper, we investigate the phase equilibrium problem for multicomponent mixtures under specified internal energy (<span><math><mi>U</mi></math></span>), volume (<span><math><mi>V</mi></math></span>), and mole numbers (<span><math><mrow><msub><mrow><mi>N</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>N</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>N</mi></mrow><mrow><mi>n</mi></mrow></msub></mrow></math></span>), commonly known as the UVN-flash problem. While conventional phase equilibrium calculations typically use pressure–temperature-mole number (<span><math><mrow><mi>P</mi><mi>T</mi><mi>N</mi></mrow></math></span>) specifications, the UVN formulation is essential for dynamic simulations of closed systems and energy balance computations. Existing approaches, including those based on iterative pressure–temperature updates and direct entropy maximization, can suffer from computational inefficiencies due to inner Newton iterations needed to solve for temperature <span><math><mi>T</mi></math></span> at specified internal energy <span><math><mi>U</mi></math></span> and volume <span><math><mi>V</mi></math></span>.</div><div>In this work, we present a reformulation of the UVN-flash problem that eliminates the need for the inner Newton iterations, addressing a computational bottleneck. We begin with stability analysis and discuss a strategy to generate the initial guess for the UVN-flash from the stability analysis results. We then reformulate the UVN-flash problem in TVN-space as constrained entropy maximization. We provide a detailed derivation of Michelsen’s Q-function using the method of Lagrange multipliers, illustrating its direct application in solving the UVN-flash problem. Furthermore, we discuss the numerical methods used, including gradient and Hessian computations. The reformulation is validated against benchmark cases, demonstrating improved efficiency.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114528"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144672324","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}

{"title":"Experimental determination and correlation of solubility for R1234ze(E) in POE, PVE, and PAG base oils","authors":"Tao Jia ,&nbsp;Jinpeng Yang ,&nbsp;Jia Yu","doi":"10.1016/j.fluid.2025.114529","DOIUrl":"10.1016/j.fluid.2025.114529","url":null,"abstract":"<div><div>Detailed knowledge about the solubility of refrigerant in oil is essential for the design, operation, and long-term reliability of HVAC and refrigeration systems. Herein, as the leading candidates, the solubilities of R1234ze(E) in polyol ester (POE), polyvinylether (PVE), and polyalkylene glycol (PAG) base oils were investigated using the isochoric saturation method at temperatures from 283 K to 353 K. The viscosity grade of the three base oils is ISO VG 68. Additionally, the Peng-Robinson (PR) + Wilson model was successfully applied to correlate the experimental data. The absolute average relative deviations between the experimental and calculated pressures for R1234ze(E) in POE, PVE, and PAG base oils were 1.56 %, 0.91 %, and 1.46 %, respectively. These results provide valuable physical property data for the selection of suitable oils in vapor compression refrigeration systems.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114529"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633707","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}

{"title":"Molecular dynamics simulation study on the selective extraction of 1,3 propanediol from fermentation broth using imidazolium-based hydrophobic ionic liquids","authors":"Raj Akshat ,&nbsp;Anand Bharti ,&nbsp;Padmini Padmanabhan","doi":"10.1016/j.fluid.2025.114530","DOIUrl":"10.1016/j.fluid.2025.114530","url":null,"abstract":"<div><div>Selective extraction of dilute 1,3 propanediol (1,3-PDO) (&lt;20 wt %) from the fermentation broth is challenging via conventional distillation as the process becomes energy-intensive. Liquid-liquid extraction (LLE) using solvents such as ionic liquids (ILs) may significantly reduce costs. Therefore, this study explored the potential of imidazolium-based hydrophobic ILs for the selective extraction of 1,3-PDO from a fermentation broth containing 1,3-PDO, 2,3-butanediol (2,3-BDO), glycerol (Gly), and water using molecular dynamics simulations. Three ILs, having the same cation, 1‑butyl‑3‑methylimidazolium ([Bmim]⁺), but different anions-hexafluorophosphate ([PF₆]⁻), bis(trifluoromethylsulfonyl)imide ([NTF₂]⁻), and trifluoromethanesulfonate ([TFO]⁻)-were investigated. The local mass density profiles confirmed a well-defined biphasic system for all ILs. [Bmim][PF₆] and [Bmim][TFO] showed excellent results, with 1.3-PDO distribution coefficients ranging from 2.53 to 6.71 and 4.12 to 15.40, respectively. The selectivity towards 1.3-PDO relative to water ranged from 50.6 to 192.50, while selectivity relative to glycerol (2.88–13.83) and 2,3-BDO (4.59–25.67) was also notably high. [Bmim][TFO] exhibited the strongest affinity for 1,3-PDO, with the highest binding energies and more favorable hydrogen bonds. Furthermore, diffusion coefficient analysis indicated that PDO exhibited lower diffusion rates in the extraction phase. Radial distribution function (RDF), spatial distribution function (SDF), and coordination number (CN) analyses confirmed a compact solvation shell and higher 1,3-PDO density around [Bmim][TFO]. Supported by COSMO-SAC thermodynamic model predictions, the study demonstrated that the anion plays a critical role in IL performance. Overall, the results established the extraction performance trend as [Bmim][TFO] &gt; [Bmim][PF₆] &gt; [Bmim][NTF₂], highlighting [Bmim][TFO] as a promising candidate for selective PDO recovery.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114530"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144633706","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}

{"title":"Adsorption of tetracycline using aspartic acid and polypyrrole-functionalized multiwalled carbon nanotubes: Kinetic, isotherm, and thermodynamic analysis","authors":"Amirhossein Khazaie ,&nbsp;Amir Hessam Hassani ,&nbsp;Elham Moniri ,&nbsp;Mahsasadat Miralinaghi","doi":"10.1016/j.fluid.2025.114531","DOIUrl":"10.1016/j.fluid.2025.114531","url":null,"abstract":"<div><div>This study investigates the adsorption of tetracycline from aqueous solutions using a novel nanocomposite adsorbent composed of multi-walled carbon nanotubes functionalized with aspartic acid and poly-pyrrole. Batch adsorption experiments were conducted to evaluate the effects of pH, contact time, temperature, and initial concentration on adsorption efficiency. The maximum adsorption capacity was found to be 38.08 mg/g at pH 5, 25 °C, and an initial TC concentration of 100 mg/L. Kinetic data were best described by the pseudo-second-order model, indicating chemisorption, while equilibrium data fit well with the Langmuir isotherm model, confirming monolayer adsorption. Thermodynamic parameters revealed that the adsorption process is spontaneous and exothermic, with ΔG° values ranging from –11.9 to –11.11 kJ/mol and ΔH° = -21.34 kJ/mol. These findings suggest that MWCNT-Asp-PPy is an efficient, high-capacity adsorbent for TC removal, with promising applications in water treatment.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114531"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686010","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}

{"title":"A novel cubic equation of state of a flexible Zc","authors":"Lihang Bai ,&nbsp;Yulong Ji ,&nbsp;Haifeng Ma ,&nbsp;Bohao Wu ,&nbsp;Maogang He ,&nbsp;Wenze Zhu","doi":"10.1016/j.fluid.2025.114527","DOIUrl":"10.1016/j.fluid.2025.114527","url":null,"abstract":"<div><div>Classical cubic equations of state (EoSs) cannot produce satisfactory predictions for dense-state fluids because of the missing molecular repulsion effect. This work introduces a newly developed cubic EoS of a flexible critical compressibility Z_c by incorporating a repulsion term. Its <em>α</em>-function is redefined and capable of reliable extrapolation throughout the entire temperature range. As straightforward as the Soave-Redlich-Kwong (SRK) EoS, all the necessary parameters of the new EoS can be determined using the critical properties (<em>T</em>_c, <em>p</em>_c, <em>v</em>_c) and acentric factors. Tested upon pure and multi-component fluids, the new EoS demonstrates superior robustness and accuracy compared to the SRK EoS.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114527"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632860","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}