Pub Date : 2026-01-01Epub Date: 2025-08-23DOI: 10.1016/j.fluid.2025.114572
William Graf von Westarp, Janik Hense, Moritz Haas, Andreas Jupke
2,3-butanediol (2,3-BDO) is a versatile platform chemical that can be produced via fermentation in aqueous solution. The energy intensive recovery of the high boiling 2,3-BDO from water via distillation hinders the economic viability of biotechnological produced 2,3-BDO. Hence, extraction-distillation processes using novel solvents from the class of terpenoids, namely menthol, thymol, and carvacrol, are proposed. To this end, binary and ternary liquid-liquid equilibrium (LLE) data for H2O, 2,3-BDO, and each terpenoid, as well as boiling point data for 2,3-BDO and the respective terpenoid, are measured. The thermodynamic phase equilibria are correlated with the non-random two liquid (NRTL) model and consecutive process design of the extraction-distillation processes is conducted using Aspen Plus. Conventional solvents (isobutanol, 1-butanol, and oleylalcohol), thymol, and carvacrol are assessed in terms of specific exergy demand for the production of 2,3-BDO. The lowest specific exergy demands were found for oleyl alcohol (5.38 kJ g−1) and thymol (5.14 kJ g−1), carvacrol (5.49 kJ g−1). Hence, terpenoids are a competitive class of solvents and should be included in solvent screening approaches.
{"title":"Terpenoids as solvents for the separation of 2,3-butanediol from water: Phase equilibria and process evaluation","authors":"William Graf von Westarp, Janik Hense, Moritz Haas, Andreas Jupke","doi":"10.1016/j.fluid.2025.114572","DOIUrl":"10.1016/j.fluid.2025.114572","url":null,"abstract":"<div><div>2,3-butanediol (2,3-BDO) is a versatile platform chemical that can be produced via fermentation in aqueous solution. The energy intensive recovery of the high boiling 2,3-BDO from water via distillation hinders the economic viability of biotechnological produced 2,3-BDO. Hence, extraction-distillation processes using novel solvents from the class of terpenoids, namely menthol, thymol, and carvacrol, are proposed. To this end, binary and ternary liquid-liquid equilibrium (LLE) data for H<sub>2</sub>O, 2,3-BDO, and each terpenoid, as well as boiling point data for 2,3-BDO and the respective terpenoid, are measured. The thermodynamic phase equilibria are correlated with the non-random two liquid (NRTL) model and consecutive process design of the extraction-distillation processes is conducted using Aspen Plus. Conventional solvents (isobutanol, 1-butanol, and oleylalcohol), thymol, and carvacrol are assessed in terms of specific exergy demand for the production of 2,3-BDO. The lowest specific exergy demands were found for oleyl alcohol (5.38 kJ g<sup>−1</sup>) and thymol (5.14 kJ g<sup>−1</sup>), carvacrol (5.49 kJ g<sup>−1</sup>). Hence, terpenoids are a competitive class of solvents and should be included in solvent screening approaches.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"600 ","pages":"Article 114572"},"PeriodicalIF":2.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144916915","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}
Isothermal phase equilibria of carbon dioxide (CO2) + sulfur hexafluoride (SF6) mixed gas hydrate at temperatures of 281.85 K, 284.05 K, 288.05 K, 291.05 K, 291.74 K, and 292.20 K were measured so as to improve the mechanical properties of marine sediment by hydrate cementation. The addition of SF6 significantly reduces the equilibrium pressure of CO2-containing mixed gas hydrate at each temperature. At temperatures above the quadruple point Q2 (pure CO2 hydrate + aqueous + CO2-rich liquid + vapor phases) of 283.22 K, the four-phase (mixed gas hydrate + aqueous + guest-rich liquid + vapor phases) equilibrium point(s) exists(exist) on the isotherms of the CO2+SF6 mixed gas hydrate system. The four-phase equilibrium curve was connected from the quadruple point Q2 of pure CO2 hydrate to that of pure SF6 hydrate and had a maximum temperature point at 292.0 ± 0.2 K, which is higher than both the Q2 temperatures of pure CO2 hydrate and pure SF6 hydrate. Therefore, the addition of SF6 to CO2 brings a significant effect to expand the thermodynamically stable region of CO2-containing mixed gas hydrate in order for simultaneous CO2 storage and sediment improvement to be realized at marine sediment.
{"title":"Phase equilibria of carbon dioxide + sulfur hexafluoride mixed gas hydrate as fundamental data toward improving the mechanical properties of marine sediments","authors":"Tasuku Ishikawa , Takeshi Sugahara , Takayuki Hirai , Norimasa Yoshimoto","doi":"10.1016/j.fluid.2025.114525","DOIUrl":"10.1016/j.fluid.2025.114525","url":null,"abstract":"<div><div>Isothermal phase equilibria of carbon dioxide (CO<sub>2</sub>) + sulfur hexafluoride (SF<sub>6</sub>) mixed gas hydrate at temperatures of 281.85 K, 284.05 K, 288.05 K, 291.05 K, 291.74 K, and 292.20 K were measured so as to improve the mechanical properties of marine sediment by hydrate cementation. The addition of SF<sub>6</sub> significantly reduces the equilibrium pressure of CO<sub>2</sub>-containing mixed gas hydrate at each temperature. At temperatures above the quadruple point Q<sub>2</sub> (pure CO<sub>2</sub> hydrate + aqueous + CO<sub>2</sub>-rich liquid + vapor phases) of 283.22 K, the four-phase (mixed gas hydrate + aqueous + guest-rich liquid + vapor phases) equilibrium point(s) exists(exist) on the isotherms of the CO<sub>2</sub>+SF<sub>6</sub> mixed gas hydrate system. The four-phase equilibrium curve was connected from the quadruple point Q<sub>2</sub> of pure CO<sub>2</sub> hydrate to that of pure SF<sub>6</sub> hydrate and had a maximum temperature point at 292.0 ± 0.2 K, which is higher than both the Q<sub>2</sub> temperatures of pure CO<sub>2</sub> hydrate and pure SF<sub>6</sub> hydrate. Therefore, the addition of SF<sub>6</sub> to CO<sub>2</sub> brings a significant effect to expand the thermodynamically stable region of CO<sub>2</sub>-containing mixed gas hydrate in order for simultaneous CO<sub>2</sub> storage and sediment improvement to be realized at marine sediment.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114525"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579991","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 : 2026-01-01Epub Date: 2025-07-18DOI: 10.1016/j.fluid.2025.114532
Yi-Min Chen, Yu-Fan Chen, Yu-Jeng Lin
Partially replacing water with N-methyl-2-pyrrolidone (NMP) in aqueous monoethanolamine (MEA) solutions has been shown to reduce the energy demand of CO2 capture. However, the absence of rigorous thermodynamic models for semi-aqueous MEA-NMP solvents hinders process design and optimization. This study develops a thermodynamic model for CO₂ absorption in NMP–H2O–MEA–CO2 mixtures using the electrolyte NRTL framework. The model extends the established H2O–MEA–CO2 system by incorporating NMP-specific parameters while preserving accuracy in the aqueous regime. A sequential regression approach is applied to correlate key properties relevant to CO2 capture, including CO₂ solubility, excess enthalpy, heat of absorption, and liquid heat capacity across binary to quaternary systems. Viscosity and density are also modeled to support mass transfer calculations. To improve model accuracy, new CO2 solubility data are measured for NMP–H₂O–MEA–CO2 mixtures at 313–393 K. The model accurately represents CO2 solubility across a wide range of CO2 loadings, temperatures, and NMP contents, revealing a decrease in solubility and a 10–25 kJ/mol CO2 increase in heat of absorption with NMP addition. The developed model enables rigorous process simulation and facilitates the design of energy-efficient CO2 capture using semi-aqueous MEA-NMP solvents.
在单乙醇胺（MEA）水溶液中用n -甲基-2-吡咯烷酮（NMP）部分取代水已被证明可以减少二氧化碳捕获的能源需求。然而，缺乏严格的半水MEA-NMP溶剂热力学模型阻碍了工艺设计和优化。本研究利用电解质NRTL框架建立了NMP-H2O-MEA-CO2混合物中CO₂吸收的热力学模型。该模型通过纳入nmp特异性参数扩展了已建立的H2O-MEA-CO2系统，同时保持了水态的准确性。序列回归方法应用于关联与CO2捕获相关的关键特性，包括CO2溶解度、过剩焓、吸收热和跨二元到四元体系的液体热容。粘度和密度也建模，以支持传质计算。为了提高模型精度，在313-393 K下测量了NMP-H₂- mea - CO2混合物的新的CO2溶解度数据。该模型准确地代表了二氧化碳在广泛的二氧化碳负荷、温度和NMP含量范围内的溶解度，揭示了加入NMP后，二氧化碳的溶解度降低，吸收热增加10-25 kJ/mol。开发的模型能够进行严格的过程模拟，并促进使用半水MEA-NMP溶剂的节能CO2捕获设计。
{"title":"Thermodynamic modeling CO2 absorption in semi-aqueous monoethanolamine with N-methyl-2-pyrrolidone using electrolyte NRTL model","authors":"Yi-Min Chen, Yu-Fan Chen, Yu-Jeng Lin","doi":"10.1016/j.fluid.2025.114532","DOIUrl":"10.1016/j.fluid.2025.114532","url":null,"abstract":"<div><div>Partially replacing water with N-methyl-2-pyrrolidone (NMP) in aqueous monoethanolamine (MEA) solutions has been shown to reduce the energy demand of CO<sub>2</sub> capture. However, the absence of rigorous thermodynamic models for semi-aqueous MEA-NMP solvents hinders process design and optimization. This study develops a thermodynamic model for CO₂ absorption in NMP–H<sub>2</sub>O–MEA–CO<sub>2</sub> mixtures using the electrolyte NRTL framework. The model extends the established H<sub>2</sub>O–MEA–CO<sub>2</sub> system by incorporating NMP-specific parameters while preserving accuracy in the aqueous regime. A sequential regression approach is applied to correlate key properties relevant to CO<sub>2</sub> capture, including CO₂ solubility, excess enthalpy, heat of absorption, and liquid heat capacity across binary to quaternary systems. Viscosity and density are also modeled to support mass transfer calculations. To improve model accuracy, new CO<sub>2</sub> solubility data are measured for NMP–H₂O–MEA–CO<sub>2</sub> mixtures at 313–393 K. The model accurately represents CO<sub>2</sub> solubility across a wide range of CO<sub>2</sub> loadings, temperatures, and NMP contents, revealing a decrease in solubility and a 10–25 kJ/mol CO<sub>2</sub> increase in heat of absorption with NMP addition. The developed model enables rigorous process simulation and facilitates the design of energy-efficient CO<sub>2</sub> capture using semi-aqueous MEA-NMP solvents.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114532"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694298","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 : 2026-01-01Epub Date: 2025-07-05DOI: 10.1016/j.fluid.2025.114524
Pengshuai Zhang , Binbin Wu , Ranran Feng , Jiaxuan Xu , Jiaqi Li , Shuoye Yang , Peng Li
This study investigated the solubility of ethyl l-phenylalaninate hydrochloride (H-Phe-OEt.HCl) in seven neat solvents (1-Propanol, 1,4-Dioxane, 2-Butoxyethanol, 2-Propoxyethanol, Isopropyl alcohol, 1-Butanol, THF) and two binary (2-Propoxyethanol + THF, 2-Butoxyethanol + 1-Propanol) solvent mixtures from 283.15 K to 323.15 K under atmospheric pressure. The solubility of H-Phe-OEt.HCl in the neat solvents was correlated by the NRTL, Buchowski-Ksiazczak λh, Margules, NRTL-SAC, Jouyban and van't Hoff model. For the binary solvent mixtures (2-Propoxyethanol + THF, 2-Butoxyethanol + 1-Propanol), the NRTL, van't Hoff, Jouyban-Acree van't Hoff and Ma model were employed to correlate the obtained solubility. Hansen solubility parameters (HSPs) was used to evaluate the dissolution trend of H-Phe-OEt.HCl in the selected solvents. In addition, the apparent thermodynamic parameters such as ΔsolH° (apparent standard enthalpy change), ΔsolS° (apparent standard entropy change) and ΔsolG° (apparent standard Gibbs energy change) was calculated to evaluate the dissolution mechanism, all the positive values of ΔsolH°, ΔsolS° and ΔsolG° illustrated that the dissolution of H-Phe-OEt.HCl was an endothermic and entropy-increase process. The current study could provide critical insights for optimizing industrial crystallization, purification, and separation processes of H-Phe-OEt.HCl.
{"title":"Investigating the dissolution behavior and revealing the thermodynamic mechanism of Ethyl L-phenylalaninate hydrochloride in several neat and binary solvents","authors":"Pengshuai Zhang , Binbin Wu , Ranran Feng , Jiaxuan Xu , Jiaqi Li , Shuoye Yang , Peng Li","doi":"10.1016/j.fluid.2025.114524","DOIUrl":"10.1016/j.fluid.2025.114524","url":null,"abstract":"<div><div>This study investigated the solubility of ethyl l-phenylalaninate hydrochloride (H-Phe-OEt.HCl) in seven neat solvents (1-Propanol, 1,4-Dioxane, 2-Butoxyethanol, 2-Propoxyethanol, Isopropyl alcohol, 1-Butanol, THF) and two binary (2-Propoxyethanol + THF, 2-Butoxyethanol + 1-Propanol) solvent mixtures from 283.15 K to 323.15 K under atmospheric pressure. The solubility of H-Phe-OEt.HCl in the neat solvents was correlated by the NRTL, Buchowski-Ksiazczak λh, Margules, NRTL-SAC, Jouyban and van't Hoff model. For the binary solvent mixtures (2-Propoxyethanol + THF, 2-Butoxyethanol + 1-Propanol), the NRTL, van't Hoff, Jouyban-Acree van't Hoff and Ma model were employed to correlate the obtained solubility. Hansen solubility parameters (HSPs) was used to evaluate the dissolution trend of H-Phe-OEt.HCl in the selected solvents. In addition, the apparent thermodynamic parameters such as Δ<sub>sol</sub><em>H</em>° (apparent standard enthalpy change), Δ<sub>sol</sub><em>S</em>° (apparent standard entropy change) and Δ<sub>sol</sub><em>G</em>° (apparent standard Gibbs energy change) was calculated to evaluate the dissolution mechanism, all the positive values of Δ<sub>sol</sub><em>H</em>°, Δ<sub>sol</sub><em>S</em>° and Δ<sub>sol</sub><em>G</em>° illustrated that the dissolution of H-Phe-OEt.HCl was an endothermic and entropy-increase process. The current study could provide critical insights for optimizing industrial crystallization, purification, and separation processes of H-Phe-OEt.HCl.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114524"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144595439","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 : 2026-01-01Epub Date: 2025-07-27DOI: 10.1016/j.fluid.2025.114543
Rached Ben Mehrez , Chaker Briki , Lilia El Amraoui , Kais Ouni , Abdelmajid Jemni
This comprehensive study investigates the hydrogen absorption–desorption mechanisms in ZrMn2 compounds through a combination of experimental and theoretical approaches. The research systematically explores the alloy's physical and thermodynamic properties, emphasizing its structural integrity and thermodynamic stability. Pressure–composition–temperature (PCT) isotherms are employed to evaluate the hydrogen storage capacity and reversibility. Concurrently, theoretical models based on statistical physics are used to elucidate macroscale interactions, internal energy variations, and lattice strain behavior during hydrogen cycling. The hydrogen uptake process begins with physisorption, followed by dissociative chemisorption of hydrogen molecules at the surface, which then diffuse into the alloy matrix. The findings advance the understanding of hydrogen-intermetallic interactions and offer valuable insights for the development of ZrMn2-based materials in next-generation solid-state hydrogen storage systems, where optimizing storage capacity and kinetic performance is essential.
{"title":"Integrated experimental and theoretical investigation of hydrogen absorption and desorption in ZrMn2 compounds","authors":"Rached Ben Mehrez , Chaker Briki , Lilia El Amraoui , Kais Ouni , Abdelmajid Jemni","doi":"10.1016/j.fluid.2025.114543","DOIUrl":"10.1016/j.fluid.2025.114543","url":null,"abstract":"<div><div>This comprehensive study investigates the hydrogen absorption–desorption mechanisms in ZrMn<sub>2</sub> compounds through a combination of experimental and theoretical approaches. The research systematically explores the alloy's physical and thermodynamic properties, emphasizing its structural integrity and thermodynamic stability. Pressure–composition–temperature (PCT) isotherms are employed to evaluate the hydrogen storage capacity and reversibility. Concurrently, theoretical models based on statistical physics are used to elucidate macroscale interactions, internal energy variations, and lattice strain behavior during hydrogen cycling. The hydrogen uptake process begins with physisorption, followed by dissociative chemisorption of hydrogen molecules at the surface, which then diffuse into the alloy matrix. The findings advance the understanding of hydrogen-intermetallic interactions and offer valuable insights for the development of ZrMn<sub>2</sub>-based materials in next-generation solid-state hydrogen storage systems, where optimizing storage capacity and kinetic performance is essential.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114543"},"PeriodicalIF":2.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750247","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 : 2026-01-01Epub Date: 2025-08-09DOI: 10.1016/j.fluid.2025.114554
Yiran Wang, Zhiyu Yan, Maogang He, Xiangyang Liu
Ionic liquids (ILs) are emerging solvents, and the reliable prediction of thermodynamic properties is challenging for process design because of their diverse structures. The integration of the perturbed-chain statistical associating fluid theory equation of state (PC-SAFT EoS) with the group contribution (GC) method establishes a robust framework for thermodynamic property prediction. However, challenges remain in modeling properties of ILs through GC-PC-SAFT EoS, primarily due to limited group universality and insufficient systematic parameterization. In this study, complex anions and cations are divided into multiple smaller sub-groups, and the group contribution parameters of the GC-PC-SAFT EoS were determined based on extensive experimental data and the global search algorithm. The optimized parameterization achieved the accurate calculation, with average absolute relative deviations of 1.2% for the density and 2.5% for isobaric heat capacity across 129 ILs over a wide temperature and pressure range. Furthermore, model validation confirmed its strong predictive capability for the density, isobaric heat capacity, and speed of sound of both pure ILs and their binary mixtures.
{"title":"Optimized GC-PC-SAFT parameterization for high-accuracy thermodynamic prediction of diverse ionic liquids","authors":"Yiran Wang, Zhiyu Yan, Maogang He, Xiangyang Liu","doi":"10.1016/j.fluid.2025.114554","DOIUrl":"10.1016/j.fluid.2025.114554","url":null,"abstract":"<div><div>Ionic liquids (ILs) are emerging solvents, and the reliable prediction of thermodynamic properties is challenging for process design because of their diverse structures. The integration of the perturbed-chain statistical associating fluid theory equation of state (PC-SAFT EoS) with the group contribution (GC) method establishes a robust framework for thermodynamic property prediction. However, challenges remain in modeling properties of ILs through GC-PC-SAFT EoS, primarily due to limited group universality and insufficient systematic parameterization. In this study, complex anions and cations are divided into multiple smaller sub-groups, and the group contribution parameters of the GC-PC-SAFT EoS were determined based on extensive experimental data and the global search algorithm. The optimized parameterization achieved the accurate calculation, with average absolute relative deviations of 1.2% for the density and 2.5% for isobaric heat capacity across 129 ILs over a wide temperature and pressure range. Furthermore, model validation confirmed its strong predictive capability for the density, isobaric heat capacity, and speed of sound of both pure ILs and their binary mixtures.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"600 ","pages":"Article 114554"},"PeriodicalIF":2.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144829625","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 : 2026-01-01Epub Date: 2025-08-14DOI: 10.1016/j.fluid.2025.114551
I.V. Pylyuk, M.P. Kozlovskii, R.V. Romanik
The present work is aimed at investigating the behavior of Morse fluids in the immediate vicinity of the critical point within the framework of a cell model. This region is of both fundamental and practical importance, yet presents analytical challenges due to the significant influence of order parameter fluctuations. An analytical procedure is developed to construct the upper part of the liquid–gas coexistence curve and calculate its diameter, incorporating the non-Gaussian (quartic) distribution of fluctuations. An explicit expression is derived for the temperature-dependent analytical term appearing in the expression for the rectilinear diameter. The numerical evaluation of the relevant quantities is carried out using Morse potential parameters representative of sodium. The coexistence curve is constructed both with and without the inclusion of the analytical temperature-dependent term in the calculation. A specific condition is identified under which the agreement between the presented binodal branches and Monte Carlo simulation data from other study, extrapolated to the immediate vicinity of the critical point, is improved. It is shown that better agreement is achieved when the analytical term is included in the calculation of the liquid branch and omitted in the gas branch. The proposed analytical approach may provide useful insight for the theoretical study of critical phenomena in more complex fluid systems.
{"title":"Microscopic description of the liquid–gas coexistence curve for Morse fluids in the immediate vicinity of the critical point","authors":"I.V. Pylyuk, M.P. Kozlovskii, R.V. Romanik","doi":"10.1016/j.fluid.2025.114551","DOIUrl":"10.1016/j.fluid.2025.114551","url":null,"abstract":"<div><div>The present work is aimed at investigating the behavior of Morse fluids in the immediate vicinity of the critical point within the framework of a cell model. This region is of both fundamental and practical importance, yet presents analytical challenges due to the significant influence of order parameter fluctuations. An analytical procedure is developed to construct the upper part of the liquid–gas coexistence curve and calculate its diameter, incorporating the non-Gaussian (quartic) distribution of fluctuations. An explicit expression is derived for the temperature-dependent analytical term appearing in the expression for the rectilinear diameter. The numerical evaluation of the relevant quantities is carried out using Morse potential parameters representative of sodium. The coexistence curve is constructed both with and without the inclusion of the analytical temperature-dependent term in the calculation. A specific condition is identified under which the agreement between the presented binodal branches and Monte Carlo simulation data from other study, extrapolated to the immediate vicinity of the critical point, is improved. It is shown that better agreement is achieved when the analytical term is included in the calculation of the liquid branch and omitted in the gas branch. The proposed analytical approach may provide useful insight for the theoretical study of critical phenomena in more complex fluid systems.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"600 ","pages":"Article 114551"},"PeriodicalIF":2.7,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144852457","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 : 2026-01-01Epub Date: 2025-07-23DOI: 10.1016/j.fluid.2025.114534
Mohammad Hossein Keshavarz, Mojgan Fathi, Zeinab Shirazi
Carbon nanotubes (CNTs) are celebrated for their extraordinary mechanical, electrical, and thermal properties, yet their industrial adoption remains hindered by aggregation issues. Achieving stable dispersion in organic solvents is critical for unlocking their potential in advanced composites, flexible electronics, energy storage, and environmental remediation. Current quantitative structure-property relationship (QSPR) models for predicting CNT dispersibility rely on computationally intensive descriptors, such as quantum-chemical or topological parameters, which limit their practical accessibility. This study introduces a streamlined predictive model that uses only three intuitive solvent descriptors—hydrogen-bonding capacity, hydrophobicity, and a novel π-π interaction parameter—to achieve exceptional accuracy (training r² = 0.917, external validation r² = 0.963) and precision (RMSE = 0.236 vs. 0.337 for prior models). Innovations include leveraging amine/amide functional groups for stabilization and eliminating dependence on complex computational tools. The model’s robustness is validated through rigorous statistical testing (leave-many-out cross-validation q² = 0.823) and applicability domain analysis. By prioritizing simplicity without compromising performance, this work bridges the gap between lab-scale nanotechnology research and scalable industrial applications, such as water purification and pollution remediation, offering a user-friendly alternative to traditional QSPR frameworks.
{"title":"Mastering carbon nanotube dispersion: A simplified model for industrial and environmental innovation","authors":"Mohammad Hossein Keshavarz, Mojgan Fathi, Zeinab Shirazi","doi":"10.1016/j.fluid.2025.114534","DOIUrl":"10.1016/j.fluid.2025.114534","url":null,"abstract":"<div><div>Carbon nanotubes (CNTs) are celebrated for their extraordinary mechanical, electrical, and thermal properties, yet their industrial adoption remains hindered by aggregation issues. Achieving stable dispersion in organic solvents is critical for unlocking their potential in advanced composites, flexible electronics, energy storage, and environmental remediation. Current quantitative structure-property relationship (QSPR) models for predicting CNT dispersibility rely on computationally intensive descriptors, such as quantum-chemical or topological parameters, which limit their practical accessibility. This study introduces a streamlined predictive model that uses only three intuitive solvent descriptors—hydrogen-bonding capacity, hydrophobicity, and a novel π-π interaction parameter—to achieve exceptional accuracy (training r² = 0.917, external validation r² = 0.963) and precision (RMSE = 0.236 vs. 0.337 for prior models). Innovations include leveraging amine/amide functional groups for stabilization and eliminating dependence on complex computational tools. The model’s robustness is validated through rigorous statistical testing (leave-many-out cross-validation q² = 0.823) and applicability domain analysis. By prioritizing simplicity without compromising performance, this work bridges the gap between lab-scale nanotechnology research and scalable industrial applications, such as water purification and pollution remediation, offering a user-friendly alternative to traditional QSPR frameworks.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114534"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144714441","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 : 2026-01-01Epub Date: 2025-07-08DOI: 10.1016/j.fluid.2025.114520
Edgar Ivan Sanchez Medina , Kai Sundmacher
Predictive thermodynamic models are crucial for the early stages of product and process design. In this paper the performance of Graph Neural Networks (GNNs) embedded into a relatively simple excess Gibbs energy model, the extended Margules model, for predicting vapor–liquid equilibrium at low pressures (less than 5 bar) is analyzed. By comparing its performance against the established UNIFAC-Dortmund model it has been shown that GNNs embedded in Margules achieves an overall lower accuracy. However, higher accuracy is observed in the case of various types of binary mixtures. Moreover, since group contribution methods, like UNIFAC, are limited due to feasibility of molecular fragmentation or availability of parameters, the GNN in Margules model offers an alternative for VLE estimation. The findings establish a baseline for the predictive accuracy that simple excess Gibbs energy models combined with GNNs trained solely on infinite dilution data can achieve.
{"title":"Graph neural networks embedded into Margules model for vapor–liquid equilibria prediction","authors":"Edgar Ivan Sanchez Medina , Kai Sundmacher","doi":"10.1016/j.fluid.2025.114520","DOIUrl":"10.1016/j.fluid.2025.114520","url":null,"abstract":"<div><div>Predictive thermodynamic models are crucial for the early stages of product and process design. In this paper the performance of Graph Neural Networks (GNNs) embedded into a relatively simple excess Gibbs energy model, the extended Margules model, for predicting vapor–liquid equilibrium at low pressures (less than 5 bar) is analyzed. By comparing its performance against the established UNIFAC-Dortmund model it has been shown that GNNs embedded in Margules achieves an overall lower accuracy. However, higher accuracy is observed in the case of various types of binary mixtures. Moreover, since group contribution methods, like UNIFAC, are limited due to feasibility of molecular fragmentation or availability of parameters, the GNN in Margules model offers an alternative for VLE estimation. The findings establish a baseline for the predictive accuracy that simple excess Gibbs energy models combined with GNNs trained solely on infinite dilution data can achieve.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114520"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144595919","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 : 2026-01-01Epub Date: 2025-07-02DOI: 10.1016/j.fluid.2025.114521
Zhiyu Yan, Yiran Wang, Xiangyang Liu, Maogang He
In this study, we combined the soft-SAFT equation of state (EoS) with entropy scaling to model the correlation between viscosity and residual entropy in pure hydrocarbons and their asymmetric binary mixtures with significant molecular weight disparities. For pure hydrocarbons, the dimensionless viscosity exhibits a distinct univariate dependence on residual entropy. When extended to mixtures, the viscosity is predicted by incorporating contributions from each component without introducing additional adjustable parameters. The model was validated against 1326 experimental viscosity data points for mixtures composed of hydrocarbons with carbon numbers ranging from 5 to 24, yielding an average absolute relative deviation (AARD) of 3.71 %. For the more challenging methane-containing mixtures (where methane viscosity differs by orders of magnitude from the other component), the predictive accuracy was significantly improved with an AARD of only 4.75 %.
{"title":"Viscosity prediction of asymmetric hydrocarbon mixtures by the soft-SAFT + entropy scaling model","authors":"Zhiyu Yan, Yiran Wang, Xiangyang Liu, Maogang He","doi":"10.1016/j.fluid.2025.114521","DOIUrl":"10.1016/j.fluid.2025.114521","url":null,"abstract":"<div><div>In this study, we combined the soft-SAFT equation of state (EoS) with entropy scaling to model the correlation between viscosity and residual entropy in pure hydrocarbons and their asymmetric binary mixtures with significant molecular weight disparities. For pure hydrocarbons, the dimensionless viscosity exhibits a distinct univariate dependence on residual entropy. When extended to mixtures, the viscosity is predicted by incorporating contributions from each component without introducing additional adjustable parameters. The model was validated against 1326 experimental viscosity data points for mixtures composed of hydrocarbons with carbon numbers ranging from 5 to 24, yielding an average absolute relative deviation (AARD) of 3.71 %. For the more challenging methane-containing mixtures (where methane viscosity differs by orders of magnitude from the other component), the predictive accuracy was significantly improved with an AARD of only 4.75 %.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"599 ","pages":"Article 114521"},"PeriodicalIF":2.8,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579990","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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