Pub Date : 2026-02-01Epub Date: 2025-09-24DOI: 10.1016/j.fluid.2025.114595
Alireza Shariati , Ali Rasoolzadeh , Cor J. Peters
In this work, the hydrate equilibrium conditions of a synthetic natural gas (SNG) in the presence of pure water and three aqueous methanol solutions including 0.09570, 0.24805, and 0.50109 methanol mass fractions were measured in the pressure range of (5.06 to 12.56) MPa and temperature range of (256.74 to 291.41) K using the isochoric pressure-search method. Additionally, a modified van der Waals-Platteeuw (vdW-P) model was used to calculate the hydrate equilibrium conditions of the SNG hydrate. The UNIQUAC and Flory-Huggins (FH) activity coefficient models were applied to compute the water activity in the presence of methanol and the Peng-Robinson equation of state (PR EoS) was used for the vapor phase. It was determined that (vdW-P + PR + UNIQUAC) and (vdW-P + PR + FH) resulted in the average absolute deviations of 0.41 K and 0.25 K, respectively.
{"title":"Hydrate equilibrium conditions of a synthetic natural gas in the presence of methanol: Experimental study and thermodynamic modeling","authors":"Alireza Shariati , Ali Rasoolzadeh , Cor J. Peters","doi":"10.1016/j.fluid.2025.114595","DOIUrl":"10.1016/j.fluid.2025.114595","url":null,"abstract":"<div><div>In this work, the hydrate equilibrium conditions of a synthetic natural gas (SNG) in the presence of pure water and three aqueous methanol solutions including 0.09570, 0.24805, and 0.50109 methanol mass fractions were measured in the pressure range of (5.06 to 12.56) MPa and temperature range of (256.74 to 291.41) K using the isochoric pressure-search method. Additionally, a modified van der Waals-Platteeuw (vdW-P) model was used to calculate the hydrate equilibrium conditions of the SNG hydrate. The UNIQUAC and Flory-Huggins (FH) activity coefficient models were applied to compute the water activity in the presence of methanol and the Peng-Robinson equation of state (PR EoS) was used for the vapor phase. It was determined that (vdW-P + PR + UNIQUAC) and (vdW-P + PR + FH) resulted in the average absolute deviations of 0.41 K and 0.25 K, respectively.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114595"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217171","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 : 2026-02-01Epub Date: 2025-09-12DOI: 10.1016/j.fluid.2025.114589
You Shu , Yang Lei , Yanfen Huang , Xinyan Liu , Yuqiu Chen
The vast diversity of ionic liquids (ILs) necessitates the development of accurate predictive models to support their industrial applications. This study combines machine learning (ML) algorithms with group contribution (GC) methods to model the density and viscosity of IL-IL-H2O ternary mixtures. Three ML algorithms (i.e., ANN, XGBoost, and LightGBM) were employed to develop robust predictive models, which were trained on a large experimental dataset. The effect of dataset partitioning on the prediction results is analyzed, and the generalizability of the models is validated through 5-fold cross-validation. The ANN-GC model performs well in predicting both density and viscosity properties, with a mean absolute error (MAE) of 1.7909 and a correlation coefficient (R2) of 0.9933 for density, and an MAE of 0.0329 and an R² of 0.9813 for viscosity. Furthermore, hyperparameters for the ANN model were optimized using Bayesian optimization, while XGBoost and LightGBM were optimized via grid search. After optimization, the prediction accuracies of all three models improved, with ANN-GC maintaining the highest prediction accuracy. Specifically, the optimized ANN-GC model achieves an MAE of 1.5834 and an R2 of 0.9963 for density prediction, and an MAE of 0.0279 and an R2 of 0.9924 for viscosity prediction. Further insights were obtained through SHAP (SHapley Additive exPlanations) analysis, which clarified the contributions of different features to the model predictions. Additionally, the validity of the density and viscosity prediction models was confirmed by calculating the fluid flow unit process case.
{"title":"Modeling study on the density and viscosity of ionic liquid-ionic liquid-water ternary mixtures","authors":"You Shu , Yang Lei , Yanfen Huang , Xinyan Liu , Yuqiu Chen","doi":"10.1016/j.fluid.2025.114589","DOIUrl":"10.1016/j.fluid.2025.114589","url":null,"abstract":"<div><div>The vast diversity of ionic liquids (ILs) necessitates the development of accurate predictive models to support their industrial applications. This study combines machine learning (ML) algorithms with group contribution (GC) methods to model the density and viscosity of IL-IL-H<sub>2</sub>O ternary mixtures. Three ML algorithms (i.e., ANN, XGBoost, and LightGBM) were employed to develop robust predictive models, which were trained on a large experimental dataset. The effect of dataset partitioning on the prediction results is analyzed, and the generalizability of the models is validated through 5-fold cross-validation. The ANN-GC model performs well in predicting both density and viscosity properties, with a mean absolute error (MAE) of 1.7909 and a correlation coefficient (<em>R</em><sup>2</sup>) of 0.9933 for density, and an MAE of 0.0329 and an <em>R</em>² of 0.9813 for viscosity. Furthermore, hyperparameters for the ANN model were optimized using Bayesian optimization, while XGBoost and LightGBM were optimized via grid search. After optimization, the prediction accuracies of all three models improved, with ANN-GC maintaining the highest prediction accuracy. Specifically, the optimized ANN-GC model achieves an MAE of 1.5834 and an <em>R</em><sup>2</sup> of 0.9963 for density prediction, and an MAE of 0.0279 and an <em>R</em><sup>2</sup> of 0.9924 for viscosity prediction. Further insights were obtained through SHAP (SHapley Additive exPlanations) analysis, which clarified the contributions of different features to the model predictions. Additionally, the validity of the density and viscosity prediction models was confirmed by calculating the fluid flow unit process case.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114589"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106767","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 : 2026-02-01Epub Date: 2025-10-11DOI: 10.1016/j.fluid.2025.114606
Xinyue Lin , Dezhi Cao , Jian Hong, Dingkai Hu, Biao Liu, Xinpeng Bi, Qiang Wang
Separating heat-sensitive components such as Linalool in lavender essential oil is difficult. Traditional techniques have high energy consumption and are prone to component degradation. This paper presents an efficient method of separating the main components (Linalool, Linalyl Acetate and α-Terpineol) of lavender essential oil using decompression distillation combined with ionic liquids (ILs) extraction. Optimising the parameters of decompression distillation (pressure 5.5 kPa, full reflux for 0.5 h, reflux ratio 6) resulted in Linalool and Linalyl Acetate purities of 75.21 % and 59.39 %, respectively—wherein the purity and yield of Linalool were measured in the distillate stream, while those of Linalyl Acetate were determined in the bottoms stream. Using the conductor-like screening model for segment activity coefficient (COSMO-SAC), 1‑butyl‑4-methylpyridinium bis (trifluoromethanesulfonyl) imide ([BMPY][NTf2]) was identified as the optimal extractant. Adding 1 wt% of this compound increased the purity of Linalyl Acetate to 81%. Adding 1 wt% increased the purity of Linalyl Acetate to 81.34 %, with a yield of 61.89 %. Quantum chemical analysis showed that [BMPY][NTf2] bound to α-Terpineol via strong hydrogen bonding and that Linalyl Acetate could be more easily separated from the top of the column due to its low polarity. This study provides a green, feasible technical solution for efficiently separating thermosensitive essential oils, and establishes a theoretical foundation for applying ILs to separate complex mixtures.
{"title":"Application of COSMO screening to extractive distillation of true lavender essential oil using ionic liquids: An experimental and quantum chemical study","authors":"Xinyue Lin , Dezhi Cao , Jian Hong, Dingkai Hu, Biao Liu, Xinpeng Bi, Qiang Wang","doi":"10.1016/j.fluid.2025.114606","DOIUrl":"10.1016/j.fluid.2025.114606","url":null,"abstract":"<div><div>Separating heat-sensitive components such as Linalool in lavender essential oil is difficult. Traditional techniques have high energy consumption and are prone to component degradation. This paper presents an efficient method of separating the main components (Linalool, Linalyl Acetate and α-Terpineol) of lavender essential oil using decompression distillation combined with ionic liquids (ILs) extraction. Optimising the parameters of decompression distillation (pressure 5.5 kPa, full reflux for 0.5 h, reflux ratio 6) resulted in Linalool and Linalyl Acetate purities of 75.21 % and 59.39 %, respectively—wherein the purity and yield of Linalool were measured in the distillate stream, while those of Linalyl Acetate were determined in the bottoms stream. Using the conductor-like screening model for segment activity coefficient (COSMO-SAC), 1‑butyl‑4-methylpyridinium bis (trifluoromethanesulfonyl) imide ([BMPY][NTf<sub>2</sub>]) was identified as the optimal extractant. Adding 1 wt% of this compound increased the purity of Linalyl Acetate to 81%. Adding 1 wt% increased the purity of Linalyl Acetate to 81.34 %, with a yield of 61.89 %. Quantum chemical analysis showed that [BMPY][NTf<sub>2</sub>] bound to α-Terpineol via strong hydrogen bonding and that Linalyl Acetate could be more easily separated from the top of the column due to its low polarity. This study provides a green, feasible technical solution for efficiently separating thermosensitive essential oils, and establishes a theoretical foundation for applying ILs to separate complex mixtures.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114606"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321414","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 : 2026-02-01Epub Date: 2025-09-10DOI: 10.1016/j.fluid.2025.114584
Johannes S. Løken, Vegard G. Jervell, Morten Hammer, Bjørn Hafskjold, Thuat T. Trinh, Øivind Wilhelmsen
The Lennard-Jones/spline (LJ/s) potential is truncated and splined such that the potential and its first derivative continuously approach zero at , making it short-ranged. In this work, we present a systematic study of the thermal conductivity, shear viscosity, and self-diffusion coefficient of the LJ/s fluid. Four theories are evaluated by comparing to results from equilibrium and non-equilibrium molecular dynamics simulations for temperatures in the range and densities in the range . After regressing two parameters for each transport property in extended corresponding state theory with argon as reference fluid, the Average Absolute Relative Deviations (AARDs) with respect to the simulation data are 4.7% and 2.8% for the viscosity and thermal conductivity respectively. Using 4-6 regression parameters, residual entropy scaling yields AARDs of 5.7%, 2.6%, and 2.5% for the viscosity, thermal conductivity and self-diffusion coefficient respectively. A new method called corresponding entropic states theory is presented, which combines the concept of entropy scaling with the extended corresponding states formalism. Without any fitting parameters and with argon as reference fluid, the viscosity and thermal conductivity from the method have AARDs of 5.2% and 2.6%. For residual entropy scaling, extended corresponding states, and corresponding entropic states, the largest deviations are for the viscosity near the critical point, which can be explained by inaccuracies in the equation of state. Revised Enskog Theory, which is fully predictive, gives AARDs below 10% for , up to . More work is needed to increase the accuracy of Revised Enskog theory at lower temperatures and higher densities.
{"title":"Viscosity, thermal conductivity and self-diffusion coefficient of the Lennard-Jones spline fluid: Evaluation of theories for a short-ranged potential","authors":"Johannes S. Løken, Vegard G. Jervell, Morten Hammer, Bjørn Hafskjold, Thuat T. Trinh, Øivind Wilhelmsen","doi":"10.1016/j.fluid.2025.114584","DOIUrl":"10.1016/j.fluid.2025.114584","url":null,"abstract":"<div><div>The Lennard-Jones/spline (LJ/s) potential is truncated and splined such that the potential and its first derivative continuously approach zero at <span><math><mrow><mo>≈</mo><mn>1</mn><mo>.</mo><mn>74</mn><mi>σ</mi></mrow></math></span>, making it short-ranged. In this work, we present a systematic study of the thermal conductivity, shear viscosity, and self-diffusion coefficient of the LJ/s fluid. Four theories are evaluated by comparing to results from equilibrium and non-equilibrium molecular dynamics simulations for temperatures in the range <span><math><mrow><mn>0</mn><mo>.</mo><mn>7</mn><mo>≤</mo><msup><mrow><mi>T</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>≤</mo><mn>10</mn></mrow></math></span> and densities in the range <span><math><mrow><mn>0</mn><mo>.</mo><mn>1</mn><mo>≤</mo><msup><mrow><mi>ρ</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>≤</mo><mn>0</mn><mo>.</mo><mn>8</mn></mrow></math></span>. After regressing two parameters for each transport property in extended corresponding state theory with argon as reference fluid, the Average Absolute Relative Deviations (AARDs) with respect to the simulation data are 4.7% and 2.8% for the viscosity and thermal conductivity respectively. Using 4-6 regression parameters, residual entropy scaling yields AARDs of 5.7%, 2.6%, and 2.5% for the viscosity, thermal conductivity and self-diffusion coefficient respectively. A new method called corresponding entropic states theory is presented, which combines the concept of entropy scaling with the extended corresponding states formalism. Without any fitting parameters and with argon as reference fluid, the viscosity and thermal conductivity from the method have AARDs of 5.2% and 2.6%. For residual entropy scaling, extended corresponding states, and corresponding entropic states, the largest deviations are for the viscosity near the critical point, which can be explained by inaccuracies in the equation of state. Revised Enskog Theory, which is fully predictive, gives AARDs below 10% for <span><math><mrow><msup><mrow><mi>T</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>≥</mo><mn>3</mn></mrow></math></span>, up to <span><math><mrow><msup><mrow><mi>ρ</mi></mrow><mrow><mo>∗</mo></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>4</mn></mrow></math></span>. More work is needed to increase the accuracy of Revised Enskog theory at lower temperatures and higher densities.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114584"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106768","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 : 2026-02-01Epub Date: 2025-09-08DOI: 10.1016/j.fluid.2025.114588
Veronica Ianno’, Philippe Espeau
PEGs are often used as plasticizers in filaments formulated for FDM 3D printing. Here, we present the behavior of paracetamol in solid dispersions based on PEG 4000 and 6000 via the determination of binary phase diagrams. It is shown, as was already the case with PEG 1500, that paracetamol is present, almost obviously, in its polymorphic Form II during the second heating. This metastable form remains stable in the presence of PEG, and its solubility appears to be independent of the molar mass of PEG, as is the case for Form I. This work aims to mimic the behavior of paracetamol in the presence of PEG during an extrusion process by HME then coupled with 3D printing by FDM.
{"title":"Influence of the molar mass of PEGs on the miscibility of paracetamol: Study of binary phase diagrams. Application for FDM 3D printing","authors":"Veronica Ianno’, Philippe Espeau","doi":"10.1016/j.fluid.2025.114588","DOIUrl":"10.1016/j.fluid.2025.114588","url":null,"abstract":"<div><div>PEGs are often used as plasticizers in filaments formulated for FDM 3D printing. Here, we present the behavior of paracetamol in solid dispersions based on PEG 4000 and 6000 via the determination of binary phase diagrams. It is shown, as was already the case with PEG 1500, that paracetamol is present, almost obviously, in its polymorphic Form II during the second heating. This metastable form remains stable in the presence of PEG, and its solubility appears to be independent of the molar mass of PEG, as is the case for Form I. This work aims to mimic the behavior of paracetamol in the presence of PEG during an extrusion process by HME then coupled with 3D printing by FDM.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114588"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046870","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 : 2026-02-01Epub Date: 2025-10-08DOI: 10.1016/j.fluid.2025.114605
Huanhuan Hu , Linyun Luo , Zhongyuan Liu , Lin Tian , Guanjia Zhao
This study focuses on deep eutectic solvent (DES) systems composed of choline chloride and four alcohol-based hydrogen bond donors (glycerol, 1,3-propylene glycol, 1,2-propylene glycol, and 2,3-butylene glycol), with ethanol added at mole fractions ranging from 0 to 1. Experimental measurements of density and viscosity were conducted, and the results were validated using molecular dynamics (MD) simulations based on the GAFF force field and RESP2 charge model. The simulation results closely matched the experimental data, confirming the accuracy of the modeling approach. Radial distribution function and hydrogen bond analyses revealed that ethanol disrupts hydrogen bonds formed between the choline cation (CHO+) and the anion (Cl−), between the anion (Cl−) and the hydrogen bond donor (HBD), and among HBD molecules themselves. Instead, ethanol forms weaker new bonds with CHO+, Cl−, and HBD. Consequently, at ethanol mass fractions of 49 %, 53 %, 43 %, and 40 % in the four systems, viscosity decreased by 96 %, 88 %, 93 %, and 93 %, respectively. Despite these changes, the overall DES hydrogen bond network remained largely intact. These findings demonstrate that ethanol effectively tunes the microstructure and viscosity of DESs, enhancing their potential for practical applications.
{"title":"Experimental study and MD simulation of neutral choline–based deep eutectic solvents regulated by ethanol","authors":"Huanhuan Hu , Linyun Luo , Zhongyuan Liu , Lin Tian , Guanjia Zhao","doi":"10.1016/j.fluid.2025.114605","DOIUrl":"10.1016/j.fluid.2025.114605","url":null,"abstract":"<div><div>This study focuses on deep eutectic solvent (DES) systems composed of choline chloride and four alcohol-based hydrogen bond donors (glycerol, 1,3-propylene glycol, 1,2-propylene glycol, and 2,3-butylene glycol), with ethanol added at mole fractions ranging from 0 to 1. Experimental measurements of density and viscosity were conducted, and the results were validated using molecular dynamics (MD) simulations based on the GAFF force field and RESP2 charge model. The simulation results closely matched the experimental data, confirming the accuracy of the modeling approach. Radial distribution function and hydrogen bond analyses revealed that ethanol disrupts hydrogen bonds formed between the choline cation (CHO<sup>+</sup>) and the anion (Cl<sup>−</sup>), between the anion (Cl<sup>−</sup>) and the hydrogen bond donor (HBD), and among HBD molecules themselves. Instead, ethanol forms weaker new bonds with CHO<sup>+</sup>, Cl<sup>−</sup>, and HBD. Consequently, at ethanol mass fractions of 49 %, 53 %, 43 %, and 40 % in the four systems, viscosity decreased by 96 %, 88 %, 93 %, and 93 %, respectively. Despite these changes, the overall DES hydrogen bond network remained largely intact. These findings demonstrate that ethanol effectively tunes the microstructure and viscosity of DESs, enhancing their potential for practical applications.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114605"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321415","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 : 2026-02-01Epub Date: 2025-09-25DOI: 10.1016/j.fluid.2025.114597
Sumudu Karunarathne , Parham Bakhtavar , Lars Erik Øi
Previously reported measured density and viscosities of Monoethanolamine (MEA) + H2O, N-methyldiethanolamine (MDEA) + H2O, Dimethylethanolamine (DMEA) +H2O, and Diethylethanolamine (DEEA) +H2O mixtures were used to calculate different properties of free energy of activation for viscous flow , excess free energy of activation for viscous flow and partial molar free energy of activation for viscous flow of the components in the mixture from Eyring’s viscosity model. Redlich-Kister polynomial equations were used to represent and calculate at different temperatures and amine mole fractions. The behaviour of calculated for amines and H2O in different mixtures was discussed. The behaviour of reported partial molar volumes from our previous work was compared with to identify any similarities for these particular mixtures.
{"title":"Partial molar properties for the viscous flow of binary aqueous amine mixtures","authors":"Sumudu Karunarathne , Parham Bakhtavar , Lars Erik Øi","doi":"10.1016/j.fluid.2025.114597","DOIUrl":"10.1016/j.fluid.2025.114597","url":null,"abstract":"<div><div>Previously reported measured density and viscosities of Monoethanolamine (MEA) + H<sub>2</sub>O, N-methyldiethanolamine (MDEA) + H<sub>2</sub>O, Dimethylethanolamine (DMEA) +H<sub>2</sub>O, and Diethylethanolamine (DEEA) +H<sub>2</sub>O mixtures were used to calculate different properties of free energy of activation for viscous flow <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msup><mrow><mi>G</mi></mrow><mo>*</mo></msup></mrow></math></span> , excess free energy of activation for viscous flow <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msup><mrow><mi>G</mi></mrow><mrow><mo>*</mo><mi>E</mi></mrow></msup></mrow></math></span> and partial molar free energy of activation for viscous flow of the components in the mixture <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msubsup><mover><mi>G</mi><mo>¯</mo></mover><mi>i</mi><mo>*</mo></msubsup></mrow></math></span> from Eyring’s viscosity model. Redlich-Kister polynomial equations were used to represent <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msup><mrow><mi>G</mi></mrow><mrow><mo>*</mo><mi>E</mi></mrow></msup></mrow></math></span> and calculate <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msubsup><mover><mi>G</mi><mo>¯</mo></mover><mi>i</mi><mo>*</mo></msubsup></mrow></math></span> at different temperatures and amine mole fractions. The behaviour of calculated <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msubsup><mover><mi>G</mi><mo>¯</mo></mover><mi>i</mi><mo>*</mo></msubsup></mrow></math></span> for amines and H<sub>2</sub>O in different mixtures was discussed. The behaviour of reported partial molar volumes <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msub><mover><mi>V</mi><mo>¯</mo></mover><mi>i</mi></msub></mrow></math></span> from our previous work was compared with <span><math><mrow><mstyle><mi>Δ</mi></mstyle><msubsup><mover><mi>G</mi><mo>¯</mo></mover><mi>i</mi><mo>*</mo></msubsup></mrow></math></span> to identify any similarities for these particular mixtures.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114597"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217173","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 : 2026-02-01Epub Date: 2025-09-04DOI: 10.1016/j.fluid.2025.114574
Mami Inagaki , Kazuki Tsubaki , Sota Kawakami , Chang Yi Kong , Toshitaka Funazukuri
Piperine is one of key components of peppers, and supercritical fluid extraction has been applied to isolate such heat-sensitive natural substances. The diffusion coefficient (D12) of piperine in supercritical (sc) carbon dioxide is essential for the process design, but no data are available in the literature. In the present study the infinite dilution binary diffusion coefficient (D12) of piperine in scCO2 was measured at temperatures from 308.2 K to 343.2 K and at pressures from 12 MPa to 30 MPa by the chromatographic impulse response method, and those in methanol, ethanol, 1-propanol and 1-butanol were measured at atmospheric pressure and at temperatures from 303.2 K to 343.2 K by the Taylor dispersion method. The hydrodynamic equation, D12/T =αηβ, T is the temperature and η is the CO2 and alcohol viscosity, was found to well represent all of the D12 values measured in both scCO2 and atmospheric liquid alcohols, with a single set of two constants α = 3.655 × 10–15 kg-βmβ+2sβ-1K-1 and β = -0.9145 with the average absolute relative deviation of 4.41 % and maximum deviation of 14.0 % with 72 measurement conditions. Partial molar volumes(PMV) of piperine determined from the retention factors were negative and decreased substantially closer to the CO2 critical point, as observed for various solutes in scCO2 reported in the literature. To evaluate the accuracy of the determined PMV values new reliable models and reliable solubility data are needed to describe the PMV values, especially near the critical region.
{"title":"Measurements of infinite dilution binary diffusion coefficient and partial molar volume of piperine in supercritical carbon dioxide","authors":"Mami Inagaki , Kazuki Tsubaki , Sota Kawakami , Chang Yi Kong , Toshitaka Funazukuri","doi":"10.1016/j.fluid.2025.114574","DOIUrl":"10.1016/j.fluid.2025.114574","url":null,"abstract":"<div><div>Piperine is one of key components of peppers, and supercritical fluid extraction has been applied to isolate such heat-sensitive natural substances. The diffusion coefficient (<em>D</em><sub>12</sub>) of piperine in supercritical (sc) carbon dioxide is essential for the process design, but no data are available in the literature. In the present study the infinite dilution binary diffusion coefficient (<em>D</em><sub>12</sub>) of piperine in scCO<sub>2</sub> was measured at temperatures from 308.2 K to 343.2 K and at pressures from 12 MPa to 30 MPa by the chromatographic impulse response method, and those in methanol, ethanol, 1-propanol and 1-butanol were measured at atmospheric pressure and at temperatures from 303.2 K to 343.2 K by the Taylor dispersion method. The hydrodynamic equation, <em>D</em><sub>12</sub>/<em>T</em> =α<em>η</em><sup>β</sup>, <em>T</em> is the temperature and <em>η</em> is the CO<sub>2</sub> and alcohol viscosity, was found to well represent all of the <em>D</em><sub>12</sub> values measured in both scCO<sub>2</sub> and atmospheric liquid alcohols, with a single set of two constants <em>α</em> = 3.655 × 10<sup>–15</sup> kg<sup>-β</sup>m<sup>β+2</sup>s<sup>β-1</sup>K<sup>-1</sup> and <em>β</em> = -0.9145 with the average absolute relative deviation of 4.41 % and maximum deviation of 14.0 % with 72 measurement conditions. Partial molar volumes(PMV) of piperine determined from the retention factors were negative and decreased substantially closer to the CO<sub>2</sub> critical point, as observed for various solutes in scCO<sub>2</sub> reported in the literature. To evaluate the accuracy of the determined PMV values new reliable models and reliable solubility data are needed to describe the PMV values, especially near the critical region.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114574"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266716","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 : 2026-02-01Epub Date: 2025-09-06DOI: 10.1016/j.fluid.2025.114587
Corine Mouton, Cara E. Schwarz
This work presents measured high-pressure phase transition data for mixtures containing 1‑nonanol + n‑hexadecane (solute + solute) with supercritical CO2 (solvent) and thermodynamic modelling of the measured data. The data was measured using the static synthetic visual phase method for four (1‑nonanol + n‑hexadecane) mixtures with CO2 as well as 1‑nonanol + CO2 at temperatures between 308.2 K and 358.2 K and solute mass fractions ranging from 0.008 to 0.65 g·g-1. Solute-solute interactions strongly influence the observed phase behaviour, resulting in complex phenomena such as cosolvency effects and temperature inversions. The measured data revealed distinct cosolvency effects and exhibited temperature inversions at 308.2 K and 318.2 K for solvent-free alcohol compositions of 0 g·g-1, 0.8 g·g-1 and 1 g·g-1.
A modified version of the Soave-Redlich-Kwong (SRK) equation of state implemented in Aspen Plus®, RK‑Aspen, was used to correlate experimental pure component and binary data, and to predict the high-pressure phase transition data for the ternary system. Incorporating polar parameters, solute-solvent binary interaction parameters (BIPs), and solute-solute BIPs in the RK-Aspen model provided reasonably accurate descriptions of the measured data in the dew- and bubble point composition ranges at moderate temperatures. However, future work should focus on improving the model's performance at temperatures near the solvent's critical temperature and compositions near the mixture critical region. Additionally, an in-house thermodynamic model can be developed to better describe complex phase behaviour.
{"title":"High-pressure phase behaviour and modelling of the 1‑nonanol + n‑hexadecane + supercritical CO2 system","authors":"Corine Mouton, Cara E. Schwarz","doi":"10.1016/j.fluid.2025.114587","DOIUrl":"10.1016/j.fluid.2025.114587","url":null,"abstract":"<div><div>This work presents measured high-pressure phase transition data for mixtures containing 1‑nonanol + <em>n</em>‑hexadecane (solute + solute) with supercritical CO<sub>2</sub> (solvent) and thermodynamic modelling of the measured data. The data was measured using the static synthetic visual phase method for four (1‑nonanol + <em>n</em>‑hexadecane) mixtures with CO<sub>2</sub> as well as 1‑nonanol + CO<sub>2</sub> at temperatures between 308.2 K and 358.2 K and solute mass fractions ranging from 0.008 to 0.65 g·g<sup>-1</sup>. Solute-solute interactions strongly influence the observed phase behaviour, resulting in complex phenomena such as cosolvency effects and temperature inversions. The measured data revealed distinct cosolvency effects and exhibited temperature inversions at 308.2 K and 318.2 K for solvent-free alcohol compositions of 0 g·g<sup>-1</sup>, 0.8 g·g<sup>-1</sup> and 1 g·g<sup>-1</sup>.</div><div>A modified version of the Soave-Redlich-Kwong (SRK) equation of state implemented in Aspen Plus®, RK‑Aspen, was used to correlate experimental pure component and binary data, and to predict the high-pressure phase transition data for the ternary system. Incorporating polar parameters, solute-solvent binary interaction parameters (BIPs), and solute-solute BIPs in the RK-Aspen model provided reasonably accurate descriptions of the measured data in the dew- and bubble point composition ranges at moderate temperatures. However, future work should focus on improving the model's performance at temperatures near the solvent's critical temperature and compositions near the mixture critical region. Additionally, an in-house thermodynamic model can be developed to better describe complex phase behaviour.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114587"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061124","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 : 2026-02-01Epub Date: 2025-09-30DOI: 10.1016/j.fluid.2025.114602
Rou Zhang , Fanfan Li , Yazhou Li , Xingchuan Yang , Chunmei Cao , Li Xu , Yi Yu
This study investigated the dissolution behavior of O-methylphenylacetic acid (OMPA) in twelve organic solvent systems (methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, acetone, acetonitrile, dichloromethane, 1,2-dichloroethane, methyl acetate, ethyl acetate) across eight temperature gradients. The solubility of all tested solvents increased with temperature, and acetone exhibited the highest solubility among them. A multidimensional research approach was employed to elucidate the mechanisms underlying the dissolution process. This approach integrated molecular electrostatic potential surface (MEPS) analysis, the interpretation of solvent physicochemical parameters, and density functional theory (DFT) calculations. Six thermodynamic models (λh, modified Apelblat, van't Hoff, Yaws, Wilson, and Jouyban models) were applied to correlate the regularity of solubility evolution. The validity of these models was evaluated through ARD and RMSD. Among these models examined, the Yaws model demonstrated optimal fitting performance with a 100ARD average of 0.8221. Additionally, thermodynamic analysis revealed patterns concerning changes in the apparent mixed Gibbs free energy (ΔsolG), the apparent mixing enthalpy change (ΔsolH), and the apparent mixing entropy change (ΔsolS) throughout the dissolution process. It was observed that the dissolution of OMPA is endothermic and driven by an increase in entropy.
{"title":"The solubility of O-methylphenylacetic acid (OMPA) in different pure solvents, corrections and thermodynamic properties","authors":"Rou Zhang , Fanfan Li , Yazhou Li , Xingchuan Yang , Chunmei Cao , Li Xu , Yi Yu","doi":"10.1016/j.fluid.2025.114602","DOIUrl":"10.1016/j.fluid.2025.114602","url":null,"abstract":"<div><div>This study investigated the dissolution behavior of O-methylphenylacetic acid (OMPA) in twelve organic solvent systems (methanol, ethanol, <em>n</em>-propanol, <em>i</em>-propanol, <em>n</em>-butanol, <em>i</em>-butanol, acetone, acetonitrile, dichloromethane, 1,2-dichloroethane, methyl acetate, ethyl acetate) across eight temperature gradients. The solubility of all tested solvents increased with temperature, and acetone exhibited the highest solubility among them. A multidimensional research approach was employed to elucidate the mechanisms underlying the dissolution process. This approach integrated molecular electrostatic potential surface (MEPS) analysis, the interpretation of solvent physicochemical parameters, and density functional theory (DFT) calculations. Six thermodynamic models (<em>λh</em>, modified Apelblat, van't Hoff, Yaws, Wilson, and Jouyban models) were applied to correlate the regularity of solubility evolution. The validity of these models was evaluated through <em>ARD</em> and <em>RMSD</em>. Among these models examined, the Yaws model demonstrated optimal fitting performance with a 100<em>ARD</em> average of 0.8221. Additionally, thermodynamic analysis revealed patterns concerning changes in the apparent mixed Gibbs free energy (Δ<sub>sol</sub><em>G</em>), the apparent mixing enthalpy change (Δ<sub>sol</sub><em>H</em>), and the apparent mixing entropy change (Δ<sub>sol</sub><em>S</em>) throughout the dissolution process. It was observed that the dissolution of OMPA is endothermic and driven by an increase in entropy.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"601 ","pages":"Article 114602"},"PeriodicalIF":2.7,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266717","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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