Two binary systems containing CO2 and a branched alkane were newly studied in this work: CO2 + 2,3,4-trimethylpentane and CO2 + 2,2,4,6,6-pentamethylheptane. Their fluid phase behavior was investigated using a high-pressure variable-volume cell and a synthetic method. Saturation pressures were visually measured from (293.15 et 363.15) K and for 10 different CO2 mole fractions for both mixtures.
Whatever the considered system, no liquid-liquid immiscibility was observed in this temperature range, suggesting a continuous vapor-liquid critical curve between the pure components critical points. A total of 160 points were acquired: 149 bubble points and 11 dew points.
These new experimental data were satisfactory modeled by using the Peng-Robinson equation of state with a temperature-dependent interaction parameter, kij(T), fitted against the data.
{"title":"The CO2 + 2,3,4-trimethylpentane and CO2 + 2,2,4,6,6-pentamethylheptane binary systems: high–pressure phase equilibria measurements","authors":"Stéphane Vitu , Vincent Caqueret , Jean-Luc Daridon , Jean-Patrick Bazile","doi":"10.1016/j.fluid.2025.114648","DOIUrl":"10.1016/j.fluid.2025.114648","url":null,"abstract":"<div><div>Two binary systems containing CO<sub>2</sub> and a branched alkane were newly studied in this work: CO<sub>2</sub> + 2,3,4-trimethylpentane and CO<sub>2</sub> + 2,2,4,6,6-pentamethylheptane. Their fluid phase behavior was investigated using a high-pressure variable-volume cell and a synthetic method. Saturation pressures were visually measured from (293.15 et 363.15) K and for 10 different CO<sub>2</sub> mole fractions for both mixtures.</div><div>Whatever the considered system, no liquid-liquid immiscibility was observed in this temperature range, suggesting a continuous vapor-liquid critical curve between the pure components critical points. A total of 160 points were acquired: 149 bubble points and 11 dew points.</div><div>These new experimental data were satisfactory modeled by using the Peng-Robinson equation of state with a temperature-dependent interaction parameter, <em>k<sub>ij</sub></em>(<em>T</em>), fitted against the data.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"603 ","pages":"Article 114648"},"PeriodicalIF":2.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682419","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}
R1270 and R1234ze(E) are environmentally friendly refrigerants with GWP<1 and zero ODP, and the lubricants used in refrigeration system applications need to be matched to the alternative refrigerants and exhibit suitable solubility. In this paper, phase equilibrium studies of R1270 and R1234ze(E) in polyvinyl ether (PVE) lubricants are carried out based on the isovolumetric saturation method. The experimental temperatures ranged from 283.15 to 353.15 K and the pressures ranged from 0 MPa to 2.0 MPa, and the viscosities of the lubricants are determined by viscometers after the solubilisation of the refrigerants, and analysed by molecular dynamics simulations. The microscopic interaction between the refrigerant and the lubricant is analysed by molecular dynamics simulation. The results showed that the solubility of the two refrigerants in PVE68 decreased with increasing temperature, and the solubility of R1270 in PVE68 is smaller than that of R1234ze(E) in PVE68, which is mainly attributed to the strong interactions between fluorine atoms and oxygen atoms during the dissolution process of R1234ze(E) and PVE68. In addition, the viscosity of R1270/PVE68 mixture is lower than that of R1234ze(E)/PVE68 mixture, and the difference in viscosity between the two is smaller; meanwhile, the self-diffusion coefficient D of R1270 is larger than that of R1234ze(E), indicating that the viscosity of the mixture and the self-diffusion coefficient D showed a negative correlation.
{"title":"Experimental study and molecular dynamics modelling of R1270 and R1234ze(E) with polyvinyl ether","authors":"Bujian Zhang, Zhao Yang, Xueling Liu, Hongxia He, Zhaoning Hou, Lei Gao","doi":"10.1016/j.fluid.2025.114634","DOIUrl":"10.1016/j.fluid.2025.114634","url":null,"abstract":"<div><div>R1270 and R1234ze(E) are environmentally friendly refrigerants with GWP<1 and zero ODP, and the lubricants used in refrigeration system applications need to be matched to the alternative refrigerants and exhibit suitable solubility. In this paper, phase equilibrium studies of R1270 and R1234ze(E) in polyvinyl ether (PVE) lubricants are carried out based on the isovolumetric saturation method. The experimental temperatures ranged from 283.15 to 353.15 K and the pressures ranged from 0 MPa to 2.0 MPa, and the viscosities of the lubricants are determined by viscometers after the solubilisation of the refrigerants, and analysed by molecular dynamics simulations. The microscopic interaction between the refrigerant and the lubricant is analysed by molecular dynamics simulation. The results showed that the solubility of the two refrigerants in PVE68 decreased with increasing temperature, and the solubility of R1270 in PVE68 is smaller than that of R1234ze(E) in PVE68, which is mainly attributed to the strong interactions between fluorine atoms and oxygen atoms during the dissolution process of R1234ze(E) and PVE68. In addition, the viscosity of R1270/PVE68 mixture is lower than that of R1234ze(E)/PVE68 mixture, and the difference in viscosity between the two is smaller; meanwhile, the self-diffusion coefficient <em>D</em> of R1270 is larger than that of R1234ze(E), indicating that the viscosity of the mixture and the self-diffusion coefficient <em>D</em> showed a negative correlation.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"603 ","pages":"Article 114634"},"PeriodicalIF":2.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682421","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 : 2026-03-01Epub Date: 2025-11-01DOI: 10.1016/j.fluid.2025.114613
Alexandre M.S. Jorge , Ramesh L. Gardas , Jorge F.B. Pereira
The textile industry is a major global consumer and polluter of water, with dye-contaminated wastewater posing serious environmental risks. Aqueous Two-Phase Systems (ATPS), particularly those based on alcohol/salt combinations, present a simple and efficient approach for dye removal owing to rapid phase separation and high solute concentration capacity. However, limited understanding of the phase separation and partition mechanisms has limited their rational design and broader industrial application. This study investigates the formation of nineteen alcohol/salt ATPS composed of short-chain alcohols [ethanol (EtOH), isopropyl alcohol (IPA), 1-propyl alcohol (PA), tert-butyl alcohol (TBA), isobutyl alcohol (IBA)] and sodium salts [acetate (NaCH3COO), citrate (Na3C6H5O7), sulphate (Na2SO4), and carbonate (Na2CO3)], as well as the partitioning behaviour of methyl red (MR) as the target compound. The results were analysed based on physicochemical properties of the alcohols and salts, and supported by thermodynamic data obtained from the COnductor-like Screening MOdel for Real Solvents (COSMO-RS). Systems formed with more hydrophobic alcohols and stronger salting-out salts exhibited larger biphasic regions, consistent with COSMO-RS predictions of higher excess Gibbs free energy of mixing (GE) for alcohol-water binary systems and lower entropic contributions (-TSE) for salt-water binary mixtures. These results allowed the differentiation between systems behaving as classic organic/aqueous systems, dominated by alcohol–water immiscibility, and aqueous two-phase systems, where phase separation is governed by a careful balance of intermolecular interactions between alcohol hydrophobicity and salt salting-out strength. Partitioning studies revealed log K values ranging from 0.4 to 3.4 and extraction efficiencies (EE) between 75 % and 100 % for MR. Larger tie-line lengths (TLL) enhanced the partitioning of MR into the more hydrophobic alcohol-rich phase. Higher log K values also correlated with increasing salting-out strength of the salts (NaCH₃COO < Na₃C₆H₅O₇ < Na₂SO₄ < Na₂CO₃). This study provides valuable thermodynamic insights into the design of alcohol/salt ATPS for dye extraction, while also distinguishing between classical organic/aqueous and all-aqueous biphasic systems based on their phase behaviour.
{"title":"Phase separation and partitioning in alcohol/salt aqueous two-phase systems: Experimental and COSMO-RS insights","authors":"Alexandre M.S. Jorge , Ramesh L. Gardas , Jorge F.B. Pereira","doi":"10.1016/j.fluid.2025.114613","DOIUrl":"10.1016/j.fluid.2025.114613","url":null,"abstract":"<div><div>The textile industry is a major global consumer and polluter of water, with dye-contaminated wastewater posing serious environmental risks. Aqueous Two-Phase Systems (ATPS), particularly those based on alcohol/salt combinations, present a simple and efficient approach for dye removal owing to rapid phase separation and high solute concentration capacity. However, limited understanding of the phase separation and partition mechanisms has limited their rational design and broader industrial application. This study investigates the formation of nineteen alcohol/salt ATPS composed of short-chain alcohols [ethanol (EtOH), isopropyl alcohol (IPA), 1-propyl alcohol (PA), <em>tert</em>-butyl alcohol (TBA), isobutyl alcohol (IBA)] and sodium salts [acetate (NaCH<sub>3</sub>COO), citrate (Na<sub>3</sub>C<sub>6</sub>H<sub>5</sub>O<sub>7</sub>), sulphate (Na<sub>2</sub>SO<sub>4</sub>), and carbonate (Na<sub>2</sub>CO<sub>3</sub>)], as well as the partitioning behaviour of methyl red (MR) as the target compound. The results were analysed based on physicochemical properties of the alcohols and salts, and supported by thermodynamic data obtained from the COnductor-like Screening MOdel for Real Solvents (COSMO-RS). Systems formed with more hydrophobic alcohols and stronger salting-out salts exhibited larger biphasic regions, consistent with COSMO-RS predictions of higher excess Gibbs free energy of mixing (<em>G</em><sup>E</sup>) for alcohol-water binary systems and lower entropic contributions (-T<em>S</em><sup>E</sup>) for salt-water binary mixtures. These results allowed the differentiation between systems behaving as classic organic/aqueous systems, dominated by alcohol–water immiscibility, and aqueous two-phase systems, where phase separation is governed by a careful balance of intermolecular interactions between alcohol hydrophobicity and salt salting-out strength. Partitioning studies revealed log <em>K</em> values ranging from 0.4 to 3.4 and extraction efficiencies (EE) between 75 % and 100 % for MR. Larger tie-line lengths (TLL) enhanced the partitioning of MR into the more hydrophobic alcohol-rich phase. Higher log <em>K</em> values also correlated with increasing salting-out strength of the salts (NaCH₃COO < Na₃C₆H₅O₇ < Na₂SO₄ < Na₂CO₃). This study provides valuable thermodynamic insights into the design of alcohol/salt ATPS for dye extraction, while also distinguishing between classical organic/aqueous and all-aqueous biphasic systems based on their phase behaviour.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114613"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145464119","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}
<div><div>The presence of impurities in CO<sub>2</sub> streams has implications in the design and operation of CCS systems. Due to the wide range of potential emitters and the chemical nature of the impurities, the phase behaviour of CO<sub>2</sub>-rich mixtures may be affected leading to integrity risks. Polar impurities, even at trace or low ppm-mol levels, can influence water solubility and induce a free aqueous phase at temperatures higher than the pure water dew point. This risk can manifest at conditions at which transport pipelines operate, highlighting the need for accurate determination of the dew point of the aqueous phase in the presence of polar molecules.</div><div>This paper evaluates the performance of various Equation of State (EoS) against experimental solubility data for polar components in CO<sub>2</sub>, aiming to highlight potential uncertainties inherent in standard industry tools used for Carbon Capture and Storage (CCS) pipeline transport systems. Specifically, the Cubic-Plus-Association (CPA) EoS, as implemented in the commercial property package <em>Multiflash</em>, was assessed for its ability to predict the solubility of polar impurities—such as methanol (MeOH), triethylene glycol (TEG), and ethylene glycol (MEG)—in binary CO<sub>2</sub>-rich systems. The results reveal the capabilities and limitations of the CPA EoS in accurately estimating polar component solubilities of polar component. Significant discrepancies were observed in the solubility predictions of MeOH, TEG, and MEG, with Average Absolute Deviations (AAD) of 34.4 %, 65.8 %, and 27.8 %, respectively. These deviations underscore the model’s limitations under varying conditions, primarily due to the complexity of intermolecular interactions and the inherent challenges in capturing them within a cubic EoS framework.</div><div>To enhance the prediction accuracy of the solubility of the polar component solubility in CO<sub>2</sub>, the CPA EoS was tuned using available literature experimental data. The EoS was optimized through a calibration process that involved fitting temperature-dependent binary interaction parameters (BIPs), and cross-association parameters. We focused on improving the accuracy of solubility predictions for MeOH, TEG, and MEG in CO<sub>2</sub>, as evidenced by a reduction in the Absolute Average Deviation (AAD) down to 21.6 %,19.3 %, and 13.4 %, respectively.</div><div>While the estimations of the CPA EoS are improved, there are still some limitations. Furthermore, experimental data deviations under similar pressure and temperature conditions, along with the limited availability of reliable measurements in CO<sub>2</sub> gas and supercritical conditions relevant to CCS pipeline operations, pose additional challenges for model validation and improving predictive capability across the wide range of conditions encountered in the CCS industry. To address these limitations, this study emphasizes the need for further experimental research to gen
{"title":"Solubility of TEG, MEG, and MeOH in CO2: Improving CPA EoS modelling for CCS transport applications","authors":"Dhanaraj Turunawarasu, Paula S.C. Farias, Ayuni Saidi, Arfa Amir, Eduardo Luna-Ortiz","doi":"10.1016/j.fluid.2025.114628","DOIUrl":"10.1016/j.fluid.2025.114628","url":null,"abstract":"<div><div>The presence of impurities in CO<sub>2</sub> streams has implications in the design and operation of CCS systems. Due to the wide range of potential emitters and the chemical nature of the impurities, the phase behaviour of CO<sub>2</sub>-rich mixtures may be affected leading to integrity risks. Polar impurities, even at trace or low ppm-mol levels, can influence water solubility and induce a free aqueous phase at temperatures higher than the pure water dew point. This risk can manifest at conditions at which transport pipelines operate, highlighting the need for accurate determination of the dew point of the aqueous phase in the presence of polar molecules.</div><div>This paper evaluates the performance of various Equation of State (EoS) against experimental solubility data for polar components in CO<sub>2</sub>, aiming to highlight potential uncertainties inherent in standard industry tools used for Carbon Capture and Storage (CCS) pipeline transport systems. Specifically, the Cubic-Plus-Association (CPA) EoS, as implemented in the commercial property package <em>Multiflash</em>, was assessed for its ability to predict the solubility of polar impurities—such as methanol (MeOH), triethylene glycol (TEG), and ethylene glycol (MEG)—in binary CO<sub>2</sub>-rich systems. The results reveal the capabilities and limitations of the CPA EoS in accurately estimating polar component solubilities of polar component. Significant discrepancies were observed in the solubility predictions of MeOH, TEG, and MEG, with Average Absolute Deviations (AAD) of 34.4 %, 65.8 %, and 27.8 %, respectively. These deviations underscore the model’s limitations under varying conditions, primarily due to the complexity of intermolecular interactions and the inherent challenges in capturing them within a cubic EoS framework.</div><div>To enhance the prediction accuracy of the solubility of the polar component solubility in CO<sub>2</sub>, the CPA EoS was tuned using available literature experimental data. The EoS was optimized through a calibration process that involved fitting temperature-dependent binary interaction parameters (BIPs), and cross-association parameters. We focused on improving the accuracy of solubility predictions for MeOH, TEG, and MEG in CO<sub>2</sub>, as evidenced by a reduction in the Absolute Average Deviation (AAD) down to 21.6 %,19.3 %, and 13.4 %, respectively.</div><div>While the estimations of the CPA EoS are improved, there are still some limitations. Furthermore, experimental data deviations under similar pressure and temperature conditions, along with the limited availability of reliable measurements in CO<sub>2</sub> gas and supercritical conditions relevant to CCS pipeline operations, pose additional challenges for model validation and improving predictive capability across the wide range of conditions encountered in the CCS industry. To address these limitations, this study emphasizes the need for further experimental research to gen","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114628"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517717","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 : 2026-03-01Epub Date: 2025-11-05DOI: 10.1016/j.fluid.2025.114617
Ibtissem Guennoun , Ilham Mokbel , Latifa Negadi , Jacques Jose , Joseph Saab
This study investigates the vapor pressures of the platform chemicals furfural and 5-methylfurfural, as well as their binary mixtures with bio-derived solvents γ-valerolactone and γ-butyrolactone, using a static isothermal apparatus. Measurements were conducted over a range of 5 Pa to 10 kPa and 273.15 K to 363.15 K. The experimental data for the pure compounds were compared with literature values, while no reference data were available for the binary systems. The results were subsequently correlated using the NRTL and UNIQUAC models.
{"title":"Experimental vapor-liquid equilibria of pure compounds and binary systems (furfural + γ-valerolactone or γ-butyrolactone) and (5-methylfurfural + γ-valerolactone or γ-butyrolactone) encountered in biorefineries","authors":"Ibtissem Guennoun , Ilham Mokbel , Latifa Negadi , Jacques Jose , Joseph Saab","doi":"10.1016/j.fluid.2025.114617","DOIUrl":"10.1016/j.fluid.2025.114617","url":null,"abstract":"<div><div>This study investigates the vapor pressures of the platform chemicals furfural and 5-methylfurfural, as well as their binary mixtures with bio-derived solvents γ-valerolactone and γ-butyrolactone, using a static isothermal apparatus. Measurements were conducted over a range of 5 Pa to 10 kPa and 273.15 K to 363.15 K. The experimental data for the pure compounds were compared with literature values, while no reference data were available for the binary systems. The results were subsequently correlated using the NRTL and UNIQUAC models.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114617"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517719","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 : 2026-03-01Epub Date: 2025-11-04DOI: 10.1016/j.fluid.2025.114614
Masoume Najafi, Fatemeh Zarei, Hosseinali Zarei
This contribution reports the PρT properties of pure Poly ethylene glycol 200 and Poly ethylene glycol 300 at 12 isotherms ranging from (293.15–473.15 K) and 19 isobars starting at 0.1 MPa up to 40 MPa. Additionally, the values of density and speed of sound for these same solvents at different temperatures T = (293.15 - 343.15 K), and ambient pressure (81.5 kPa) were measured experimentally. The PρT data were initially examined using the new modified Tammann–Tait equation to derive the thermal expansion coefficient, ( ), and isothermal compressibility, (). Finally, for the studied solvents, the parameters of the PC-SAFT equation of the state were obtained based on the PρT data. The AADs of liquid density correlated with the PC-SAFT EOS were 0.08 % and 0.06 % for PEG 200 and PEG 300, respectively.Then, the performance PC-SAFT equation was evaluated for predicting key thermodynamic properties such as thermal expansion coefficient ,(), isothermal compressibility, (), isobaric heat capacity, (), and speed of sound, ().These results were compared with values obtained from the modified Tammann– Tait equation and literature data and showed satisfactory agreement with AAD% <13 %.
{"title":"Measurements of the PρT data of liquids Poly ethylene glycol 200 and Poly ethylene glycol 300 from (293.15 to 473.15) K and up to 40 MPa: Correlating and modelling using the modified Tammann-Tait and PC-SAFT equations","authors":"Masoume Najafi, Fatemeh Zarei, Hosseinali Zarei","doi":"10.1016/j.fluid.2025.114614","DOIUrl":"10.1016/j.fluid.2025.114614","url":null,"abstract":"<div><div>This contribution reports the <em>PρT</em> properties of pure Poly ethylene glycol 200 and Poly ethylene glycol 300 at 12 isotherms ranging from (293.15–473.15 K) and 19 isobars starting at 0.1 MPa up to 40 MPa. Additionally, the values of density and speed of sound for these same solvents at different temperatures <em>T</em> = (293.15 - 343.15 K), and ambient pressure (81.5 kPa) were measured experimentally. The <em>PρT</em> data were initially examined using the new modified Tammann–Tait equation to derive the thermal expansion coefficient, (<span><math><msub><mi>α</mi><mi>P</mi></msub></math></span> ), and isothermal compressibility, (<span><math><msub><mi>κ</mi><mi>T</mi></msub></math></span>). Finally, for the studied solvents, the parameters of the PC-SAFT equation of the state were obtained based on the <em>PρT</em> data. The AADs of liquid density correlated with the PC-SAFT EOS were 0.08 % and 0.06 % for PEG 200 and PEG 300, respectively.Then, the performance PC-SAFT equation was evaluated for predicting key thermodynamic properties such as thermal expansion coefficient ,(<span><math><msub><mi>α</mi><mi>P</mi></msub></math></span>), isothermal compressibility, (<span><math><msub><mi>κ</mi><mi>T</mi></msub></math></span>), isobaric heat capacity, (<span><math><msub><mi>C</mi><mi>P</mi></msub></math></span>), and speed of sound, (<span><math><mi>u</mi></math></span>).These results were compared with values obtained from the modified Tammann– Tait equation and literature data and showed satisfactory agreement with AAD% <13 %.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114614"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517718","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 : 2026-03-01Epub Date: 2025-11-06DOI: 10.1016/j.fluid.2025.114618
Peiming Wang , Mohiedin Bagheri Hariri , Jerzy J. Kosinski , Basil Perdicakis , Andre Anderko
The dissolution behavior of iron oxides in high-temperature water containing various dissolved species is a critical factor for understanding and predicting the conditions that control flow-accelerated corrosion (FAC). Predicting the stability of passivating films under steam-generating conditions, which may give rise to FAC, requires an accurate thermodynamic model that is capable of predicting the solubility of film materials, particularly magnetite (Fe3O4), hematite (Fe2O3) and iron oxyhydroxides (FeOOH). This is essential for accurate corrosion prediction, particularly in applications such as steam generation for hydrocarbon recovery from oil sands, water/steam cycle boilers, power plants, boiler feedwater systems, etc. In this study, available experimental solubility data have been evaluated for iron oxides/hydroxides, and a comprehensive thermodynamic model has been developed using the Mixed Solvent Electrolyte (MSE) framework for temperatures up to 600 K and pressures exceeding 50 MPa. The MSE model reproduces solubility in the presence of various inorganic ions and additives used in all-volatile treatments (AVT) wherein volatile alkalizing agents are employed under either reducing conditions (i.e., AVT(R)) or oxidizing conditions (i.e., AVT(O)). The accuracy of model predictions is, in general, consistent with the inherent uncertainty of experimental solubility data while the distribution of errors is a function of pH and temperature, with elevated uncertainty observed for neutral and alkaline solutions. Further, the MSE model has been applied to predict magnetite stability across various AVT(R) scenarios with different dosages of alkaline and non-alkaline reducing agents (i.e., hydrazine, hydrogen) to provide a thermodynamic foundation for controlling environmental variables in mitigating AVT(R) flow-accelerated corrosion risks. This work is especially relevant to the Canadian oil sands industry, in particular to industrial steam generation applications such as oilfield once-through steam generation systems, where high temperatures and high pH conditions affect corrosion behavior.
{"title":"Modeling the solubility of iron oxides in wide temperature ranges: thermodynamic foundation for understanding flow-accelerated corrosion","authors":"Peiming Wang , Mohiedin Bagheri Hariri , Jerzy J. Kosinski , Basil Perdicakis , Andre Anderko","doi":"10.1016/j.fluid.2025.114618","DOIUrl":"10.1016/j.fluid.2025.114618","url":null,"abstract":"<div><div>The dissolution behavior of iron oxides in high-temperature water containing various dissolved species is a critical factor for understanding and predicting the conditions that control flow-accelerated corrosion (FAC). Predicting the stability of passivating films under steam-generating conditions, which may give rise to FAC, requires an accurate thermodynamic model that is capable of predicting the solubility of film materials, particularly magnetite (Fe<sub>3</sub>O<sub>4</sub>), hematite (Fe<sub>2</sub>O<sub>3</sub>) and iron oxyhydroxides (FeOOH). This is essential for accurate corrosion prediction, particularly in applications such as steam generation for hydrocarbon recovery from oil sands, water/steam cycle boilers, power plants, boiler feedwater systems, etc. In this study, available experimental solubility data have been evaluated for iron oxides/hydroxides, and a comprehensive thermodynamic model has been developed using the Mixed Solvent Electrolyte (MSE) framework for temperatures up to 600 K and pressures exceeding 50 MPa. The MSE model reproduces solubility in the presence of various inorganic ions and additives used in all-volatile treatments (AVT) wherein volatile alkalizing agents are employed under either reducing conditions (i.e., AVT(R)) or oxidizing conditions (i.e., AVT(O)). The accuracy of model predictions is, in general, consistent with the inherent uncertainty of experimental solubility data while the distribution of errors is a function of pH and temperature, with elevated uncertainty observed for neutral and alkaline solutions. Further, the MSE model has been applied to predict magnetite stability across various AVT(R) scenarios with different dosages of alkaline and non-alkaline reducing agents (i.e., hydrazine, hydrogen) to provide a thermodynamic foundation for controlling environmental variables in mitigating AVT(R) flow-accelerated corrosion risks. This work is especially relevant to the Canadian oil sands industry, in particular to industrial steam generation applications such as oilfield once-through steam generation systems, where high temperatures and high pH conditions affect corrosion behavior.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114618"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145517720","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 : 2026-03-01Epub Date: 2025-11-01DOI: 10.1016/j.fluid.2025.114611
Yanni Li , Yuyang Zhang , Mengqing Qi , Lihui Yi , Yiyang Yu , Wenge Yang , Yonghong Hu
Diosmetin, a natural flavonoid compound, has been demonstrated to exhibit significant neuroprotective effects by inhibiting neuroinflammation and oxidative stress, thereby ameliorating the pathological progression of Alzheimer's disease. However, its current industrial production primarily relies on chemical synthesis, where solvent selection critically impacts reaction efficiency and product purity, consequently limiting its large-scale pharmaceutical applications. This study systematically investigated the solubility behavior of diosmetin in ten pure solvents and three binary solvent systems within a temperature range of 278.15 to 323.15 K. The solubility data were accurately determined using the static equilibrium-high performance liquid chromatography method, while the solvent effects were mechanistically elucidated through an innovative combination of Hansen solubility parameters and the KAT-LSER model. By establishing a multidimensional thermodynamic correlation framework including the modified Apelblat model, λh model, CNIBS/R-K model, Jouyban-Acree model, and SUN model, the study revealed that solubility exhibited a positive correlation with temperature, with N,N-dimethylformamide demonstrating the optimal dissolution performance. Thermodynamic analysis revealed the dissolution process to be endothermic, entropy-driven and non-spontaneous, with hydrogen-bond basicity/polarity enhancing solubility while cohesion energy inhibited it. The modified Apelblat and CNIBS/R-K models exhibited optimal predictive accuracy for pure and binary systems respectively. These findings provide a crucial theoretical foundation for solvent screening and process optimization in the industrial production of diosmetin.
{"title":"Solubility behavior of diosmetin in pure and binary solvents: Thermodynamic evaluation and molecular-level interpretation","authors":"Yanni Li , Yuyang Zhang , Mengqing Qi , Lihui Yi , Yiyang Yu , Wenge Yang , Yonghong Hu","doi":"10.1016/j.fluid.2025.114611","DOIUrl":"10.1016/j.fluid.2025.114611","url":null,"abstract":"<div><div>Diosmetin, a natural flavonoid compound, has been demonstrated to exhibit significant neuroprotective effects by inhibiting neuroinflammation and oxidative stress, thereby ameliorating the pathological progression of Alzheimer's disease. However, its current industrial production primarily relies on chemical synthesis, where solvent selection critically impacts reaction efficiency and product purity, consequently limiting its large-scale pharmaceutical applications. This study systematically investigated the solubility behavior of diosmetin in ten pure solvents and three binary solvent systems within a temperature range of 278.15 to 323.15 K. The solubility data were accurately determined using the static equilibrium-high performance liquid chromatography method, while the solvent effects were mechanistically elucidated through an innovative combination of Hansen solubility parameters and the KAT-LSER model. By establishing a multidimensional thermodynamic correlation framework including the modified Apelblat model, λh model, CNIBS/R-K model, Jouyban-Acree model, and SUN model, the study revealed that solubility exhibited a positive correlation with temperature, with N,N-dimethylformamide demonstrating the optimal dissolution performance. Thermodynamic analysis revealed the dissolution process to be endothermic, entropy-driven and non-spontaneous, with hydrogen-bond basicity/polarity enhancing solubility while cohesion energy inhibited it. The modified Apelblat and CNIBS/R-K models exhibited optimal predictive accuracy for pure and binary systems respectively. These findings provide a crucial theoretical foundation for solvent screening and process optimization in the industrial production of diosmetin.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114611"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145464116","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 : 2026-03-01Epub Date: 2025-11-13DOI: 10.1016/j.fluid.2025.114629
Mars Z. Faizullin, Eugene D. Nikitin
The two-phase (liquid + vapor) heat capacities of glymes CH3(OCH2CH2)nOCH3 with n from 1 to 4 (monoglyme, diglyme, triglyme and tetraglyme), as well as ethylene glycol, 2-propanol, n-octane, and benzoic acid have been measured by a differential scanning calorimeter DSC 204 F1 Phoenix (Netzsch, Germany) at atmospheric pressure in the temperature range from 298.2 K to approximately the normal boiling points of the compounds under study. The last four compounds have served as testing ones. The saturation heat capacity and isobaric heat capacity have been calculated. The experiments with testing compounds have shown that the uncertainty of the measurements is less than 0.03. The deviations of the literature data on the isobaric heat capacity of the glymes from the values measured in this work do not in general exceed the uncertainty of the experiments. The temperature dependences of the heat capacity of glymes have been approximated by third-order polynomials. The dependence of the molar heat capacity of glymes on the number of repeating units in a molecule n is linear.
用差示扫描量热计DSC 204 F1 Phoenix （Netzsch, Germany）测量了n为1 ~ 4（单lyme，二lyme，三lyme和四lyme）的glymes CH3(OCH2CH2)nOCH3以及乙二醇，2-丙醇，正辛烷和苯甲酸的两相（液+气）热容，温度范围从298.2 K到所研究化合物的正常沸点。后四种化合物被用作测试物。计算了饱和热容和等压热容。实验结果表明，测量结果的不确定度小于0.03。文献中关于糖份等压热容的数据与本工作测量值的偏差一般不超过实验的不确定度。glymes热容量的温度依赖性已用三阶多项式近似。分子的摩尔热容与分子中重复单位的数目呈线性关系。
{"title":"Heat capacity of glymes from monoglyme to tetraglyme","authors":"Mars Z. Faizullin, Eugene D. Nikitin","doi":"10.1016/j.fluid.2025.114629","DOIUrl":"10.1016/j.fluid.2025.114629","url":null,"abstract":"<div><div>The two-phase (liquid + vapor) heat capacities of glymes CH<sub>3</sub>(OCH<sub>2</sub>CH<sub>2</sub>)<sub>n</sub>OCH<sub>3</sub> with <em>n</em> from 1 to 4 (monoglyme, diglyme, triglyme and tetraglyme), as well as ethylene glycol, 2-propanol, n-octane, and benzoic acid have been measured by a differential scanning calorimeter DSC 204 F1 Phoenix (Netzsch, Germany) at atmospheric pressure in the temperature range from 298.2 K to approximately the normal boiling points of the compounds under study. The last four compounds have served as testing ones. The saturation heat capacity and isobaric heat capacity have been calculated. The experiments with testing compounds have shown that the uncertainty of the measurements is less than 0.03. The deviations of the literature data on the isobaric heat capacity of the glymes from the values measured in this work do not in general exceed the uncertainty of the experiments. The temperature dependences of the heat capacity of glymes have been approximated by third-order polynomials. The dependence of the molar heat capacity of glymes on the number of repeating units in a molecule <em>n</em> is linear.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114629"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145569060","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 : 2026-03-01Epub Date: 2025-10-15DOI: 10.1016/j.fluid.2025.114607
Luis Felipe Sanz, Juan Antonio González, Fernando Hevia, Daniel Lozano-Martín, João Victor Alves-Laurentino, Fatemeh Pazoki, Isaías. García de la Fuente, José Carlos Cobos
Density and viscosity measurements have been performed for the systems 1-iodonaphthalene + heptane, or + decane, or + dodecane, or + tetradecane over the temperature range (288.15-308.15) K and at 94 kPa. At this end, a densitometer Anton-Paar DMA 602 and a Ubbelohde viscosimeter were used. Excess molar volumes () are large and negative and decrease when the temperature is increased, which reveals that the main contribution to arises from structural effects. The values of the deviations of dynamic viscosity from linear dependence on mole fraction are also large and negative, indicating that n-alkanes are good breakers of the interactions between 1-iodonaphthalene molecules. Different models were applied for describing viscosity data. The McAllister’s equation correlates well kinematic viscosities. Results are similar when dynamic viscosities () are correlated with the Grunberg-Nissan or Fang-He equations. This means that size effects are not relevant on the mentioned data. The adjustable parameter of the Grunberg-Nissan equation is negative for all the systems at any temperature, a typical feature of systems where dispersive interactions are dominant. This is in agreement with findings obtained in previous studies on similar n-alkane mixtures involving C6H5X (X = Cl, Br, I) or 1,2,4-trichlorobenzene or 1-chloronaphthalene. Free volume effects have little influence on the present results, well represented by the absolute rate model using residual molar Gibbs energies obtained from the DISQUAC model.
{"title":"Volumetric and viscosity data of 1-iodonaphthalene + n-alkane mixtures at (288.15-308.15) K","authors":"Luis Felipe Sanz, Juan Antonio González, Fernando Hevia, Daniel Lozano-Martín, João Victor Alves-Laurentino, Fatemeh Pazoki, Isaías. García de la Fuente, José Carlos Cobos","doi":"10.1016/j.fluid.2025.114607","DOIUrl":"10.1016/j.fluid.2025.114607","url":null,"abstract":"<div><div>Density and viscosity measurements have been performed for the systems 1-iodonaphthalene + heptane, or + decane, or + dodecane, or + tetradecane over the temperature range (288.15-308.15) K and at 94 kPa. At this end, a densitometer Anton-Paar DMA 602 and a Ubbelohde viscosimeter were used. Excess molar volumes (<span><math><msubsup><mi>V</mi><mrow><mi>m</mi></mrow><mi>E</mi></msubsup></math></span>) are large and negative and decrease when the temperature is increased, which reveals that the main contribution to <span><math><msubsup><mi>V</mi><mrow><mi>m</mi></mrow><mi>E</mi></msubsup></math></span>arises from structural effects. The values of the deviations of dynamic viscosity from linear dependence on mole fraction are also large and negative, indicating that <em>n</em>-alkanes are good breakers of the interactions between 1-iodonaphthalene molecules. Different models were applied for describing viscosity data. The McAllister’s equation correlates well kinematic viscosities. Results are similar when dynamic viscosities (<span><math><mi>η</mi></math></span>) are correlated with the Grunberg-Nissan or Fang-He equations. This means that size effects are not relevant on the mentioned data. The adjustable parameter of the Grunberg-Nissan equation is negative for all the systems at any temperature, a typical feature of systems where dispersive interactions are dominant. This is in agreement with findings obtained in previous studies on similar <em>n</em>-alkane mixtures involving C<sub>6</sub>H<sub>5</sub>X (X = Cl, Br, I) or 1,2,4-trichlorobenzene or 1-chloronaphthalene. Free volume effects have little influence on the present <span><math><mi>η</mi></math></span>results, well represented by the absolute rate model using residual molar Gibbs energies obtained from the DISQUAC model<strong>.</strong></div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"602 ","pages":"Article 114607"},"PeriodicalIF":2.7,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145340697","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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