Fluid Phase Equilibria最新文献_第6页

Molecular thermodynamics of complex coacervate systems. Part II: Measuring and modeling of the phase envelope using pePC-SAFT

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-12-05 DOI: 10.1016/j.fluid.2024.114305

Moreno Ascani , Wojciech P. Lipínski , Iris B.A. Smokers , Piramsuya Neethirajah , Max Vogel , Evan Spruijt , Gabriele Sadowski , Christoph Held

Complex coacervation is an associative liquid-liquid phase separation (LLPS) observed in aqueous solutions of oppositely charged polyions. Coacervates are relevant systems in biology, chemistry, food and cosmetics industry, medicine as well as in engineering e.g. as extracting agents, for drug delivery or as gelling, foaming or stabilizing agents. Unfortunately, accurate experimental data on equilibrium compositions of complex coacervates are still scarce in the literature. Here, the LLPS of the coacervate-forming system water-Na₂NADH-protamine sulfate was measured at T = 298.15 K and p = 1.013 bar and at different polycation/polyanion ratios. Qualitative features of the experimental phase envelope are carefully discussed based on molecular interactions in this system. Compared to equilibrium data of the system water-Na₂NADH-poly-l-lysine HBr, the system water-Na₂NADH-protamine sulfate revealed a larger miscibility gap, suggesting a strong contribution of non-coulombic interactions to the phase behavior of this coacervate system. Experimental data were successfully modeled using the recently developed pePC-SAFT (Ascani et al., Part 1, Fluid Phase Equilibria, under review). The pePC-SAFT predicted phase envelope was in very good agreement with the measured experimental points. To the best of our knowledge, this is the first time that a physically sound model was used to model the phase envelope of a biologically relevant complex coacervate system.

{"title":"Molecular thermodynamics of complex coacervate systems. Part II: Measuring and modeling of the phase envelope using pePC-SAFT","authors":"Moreno Ascani , Wojciech P. Lipínski , Iris B.A. Smokers , Piramsuya Neethirajah , Max Vogel , Evan Spruijt , Gabriele Sadowski , Christoph Held","doi":"10.1016/j.fluid.2024.114305","DOIUrl":"10.1016/j.fluid.2024.114305","url":null,"abstract":"<div><div>Complex coacervation is an associative liquid-liquid phase separation (LLPS) observed in aqueous solutions of oppositely charged polyions. Coacervates are relevant systems in biology, chemistry, food and cosmetics industry, medicine as well as in engineering e.g. as extracting agents, for drug delivery or as gelling, foaming or stabilizing agents. Unfortunately, accurate experimental data on equilibrium compositions of complex coacervates are still scarce in the literature. Here, the LLPS of the coacervate-forming system water-Na<sub>2</sub>NADH-protamine sulfate was measured at <em>T</em> = 298.15 K and p = 1.013 bar and at different polycation/polyanion ratios. Qualitative features of the experimental phase envelope are carefully discussed based on molecular interactions in this system. Compared to equilibrium data of the system water-Na<sub>2</sub>NADH-poly-l-lysine HBr, the system water-Na<sub>2</sub>NADH-protamine sulfate revealed a larger miscibility gap, suggesting a strong contribution of non-coulombic interactions to the phase behavior of this coacervate system. Experimental data were successfully modeled using the recently developed pePC-SAFT (Ascani et al., Part 1, <em>Fluid Phase Equilibria</em>, under review). The pePC-SAFT predicted phase envelope was in very good agreement with the measured experimental points. To the best of our knowledge, this is the first time that a physically sound model was used to model the phase envelope of a biologically relevant complex coacervate system.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"591 ","pages":"Article 114305"},"PeriodicalIF":2.8,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of acids produced by the dissolution of sulfur and nitrogen oxides in the performance of MEA solvent in CO2 capture: Experimental results and modeling

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-12-04 DOI: 10.1016/j.fluid.2024.114309

Fragkiskos Tzirakis , Ioannis Tsivintzelis , Panos Seferlis , Athanasios I. Papadopoulos

Solvent-based CO₂ capture is very important for the mitigation of greenhouse gases. The presence of SO₂ and NO₂ is observed in several types of CO₂-containing industrial flue gases and even small concentrations can cause significant changes in the performance of the solvent. Their effects on the CO₂ solubility have received very little attention. To simulate the effect of dissolution and accumulation of SO₂ and NO₂ acid gases on the CO₂ loading of aqueous ethanolamine (MEA) solutions, H₂SO₄ and HNO₃ were added, as sources of

{NO}_{3}^{-}

and

{SO}_{4}^{- 2}

anions, respectively. The CO₂ solubility in 30 % wt. aqueous MEA solutions containing 2.9 % wt. H₂SO₄ with and without 1.8 % wt. HNO₃ was experimentally measured using a pressure decay method at 313, 333 and 353 K and approximately 5–500 kPa. In both cases, it is revealed that the addition of H₂SO₄ and HNO₃ substantially decreases the CO₂ solubility. In addition, the modified Kent-Eisenberg model was used to predict the CO₂ solubility in all systems and at all the studied conditions. The model predictions are in satisfactory agreement with the experimental data presenting Average Absolute Deviations between 4.8 and 6.8 % in all cases.

{"title":"Effect of acids produced by the dissolution of sulfur and nitrogen oxides in the performance of MEA solvent in CO2 capture: Experimental results and modeling","authors":"Fragkiskos Tzirakis , Ioannis Tsivintzelis , Panos Seferlis , Athanasios I. Papadopoulos","doi":"10.1016/j.fluid.2024.114309","DOIUrl":"10.1016/j.fluid.2024.114309","url":null,"abstract":"<div><div>Solvent-based CO<sub>2</sub> capture is very important for the mitigation of greenhouse gases. The presence of SO<sub>2</sub> and NO<sub>2</sub> is observed in several types of CO<sub>2</sub>-containing industrial flue gases and even small concentrations can cause significant changes in the performance of the solvent. Their effects on the CO<sub>2</sub> solubility have received very little attention. To simulate the effect of dissolution and accumulation of SO<sub>2</sub> and NO<sub>2</sub> acid gases on the CO<sub>2</sub> loading of aqueous ethanolamine (MEA) solutions, H<sub>2</sub>SO<sub>4</sub> and HNO<sub>3</sub> were added, as sources of <span><math><msubsup><mtext>NO</mtext><mn>3</mn><mo>−</mo></msubsup></math></span> and <span><math><msubsup><mtext>SO</mtext><mn>4</mn><mrow><mo>−</mo><mn>2</mn></mrow></msubsup></math></span> anions, respectively. The CO<sub>2</sub> solubility in 30 % wt. aqueous MEA solutions containing 2.9 % wt. H<sub>2</sub>SO<sub>4</sub> with and without 1.8 % wt. HNO<sub>3</sub> was experimentally measured using a pressure decay method at 313, 333 and 353 K and approximately 5–500 kPa. In both cases, it is revealed that the addition of H<sub>2</sub>SO<sub>4</sub> and HNO<sub>3</sub> substantially decreases the CO<sub>2</sub> solubility. In addition, the modified Kent-Eisenberg model was used to predict the CO<sub>2</sub> solubility in all systems and at all the studied conditions. The model predictions are in satisfactory agreement with the experimental data presenting Average Absolute Deviations between 4.8 and 6.8 % in all cases.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"591 ","pages":"Article 114309"},"PeriodicalIF":2.8,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151814","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}

引用次数: 0

Investigation of vapor liquid equilibria for HFO-1336mzz(E) + HFC-1234ze(E) binary system by a novel developed cyclic-analytical apparatus

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-12-04 DOI: 10.1016/j.fluid.2024.114306

Zhiqiang Yang , Yuanhao Liao , Hong Yuan , Xiaobo Tang , Christophe Coquelet , Jijun Zeng , Sheng Han , Wei Zhang , Jian Lu

Hydrofluoroolefins (HFOs), which have excellent thermophysical properties and environmental performance, are considered as the most promising environmentally friendly alternatives to the currently used refrigerants. The vapor-liquid equilibrium (VLE) properties of fluids are the basis for the design and optimization of chemical separation and refrigeration systems. In this work, a high-precision and visual VLE experimental apparatus was developed based on the cyclic-analytical method, which mainly includes thermostatic bath, VLE cell, temperature and pressure measurement system, and gas chromatograph, etc. The expanded uncertainties of temperature, pressure, and composition measurement are 0.06 K, 0.0086 MPa, and 0.056 mole fraction, respectively. By measuring the VLE data of the known binary system and comparing it with the literature, the reliability and accuracy of the experimental apparatus were verified. The VLE data of HFO-1336mzz(E) + HFC-1234ze(E) were measured in the temperature range of 293.15 to 358.15 K. The experimental data were correlated with the Peng Robinson (PR) equation of state (EoS) combined with Mathias-Copeman alpha function (MC) and van der Waals (vdW) mixing rule (PRMC-vdW model) in order to adjust the binary interaction parameters (BIP). The VLE data was also compared with the PPR78 predictive model. The VLE investigation provides a basis for further research on the cycle performance of the mixed working fluid.

{"title":"Investigation of vapor liquid equilibria for HFO-1336mzz(E) + HFC-1234ze(E) binary system by a novel developed cyclic-analytical apparatus","authors":"Zhiqiang Yang , Yuanhao Liao , Hong Yuan , Xiaobo Tang , Christophe Coquelet , Jijun Zeng , Sheng Han , Wei Zhang , Jian Lu","doi":"10.1016/j.fluid.2024.114306","DOIUrl":"10.1016/j.fluid.2024.114306","url":null,"abstract":"<div><div>Hydrofluoroolefins (HFOs), which have excellent thermophysical properties and environmental performance, are considered as the most promising environmentally friendly alternatives to the currently used refrigerants. The vapor-liquid equilibrium (VLE) properties of fluids are the basis for the design and optimization of chemical separation and refrigeration systems. In this work, a high-precision and visual VLE experimental apparatus was developed based on the cyclic-analytical method, which mainly includes thermostatic bath, VLE cell, temperature and pressure measurement system, and gas chromatograph, etc. The expanded uncertainties of temperature, pressure, and composition measurement are 0.06 K, 0.0086 MPa, and 0.056 mole fraction, respectively. By measuring the VLE data of the known binary system and comparing it with the literature, the reliability and accuracy of the experimental apparatus were verified. The VLE data of HFO-1336mzz(E) + HFC-1234ze(E) were measured in the temperature range of 293.15 to 358.15 K. The experimental data were correlated with the Peng Robinson (PR) equation of state (EoS) combined with Mathias-Copeman alpha function (MC) and van der Waals (vdW) mixing rule (PRMC-vdW model) in order to adjust the binary interaction parameters (BIP). The VLE data was also compared with the PPR78 predictive model. The VLE investigation provides a basis for further research on the cycle performance of the mixed working fluid.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"591 ","pages":"Article 114306"},"PeriodicalIF":2.8,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151816","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}

引用次数: 0

Molecular thermodynamics of complex coacervate systems. Part I: Modeling of polyelectrolyte solutions using pePC-SAFT

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-12-02 DOI: 10.1016/j.fluid.2024.114304

Moreno Ascani, Gabriele Sadowski, Christoph Held

Rigorous molecular modeling of polyelectrolyte solutions is complicated by several intrinsic challenges of those systems, such as the strong charge correlation and the complex cocktail of short-range and long-range interactions, which span over a broad length scale. On the other hand, there is an increasing interest in understanding and designing polyelectrolyte systems in biology, life science, medicine, and (bio)chemical engineering. Thermodynamics of polyelectrolyte solutions is rather underexplored, and the difficulties in describing polyelectrolytes at the molecular level as well as the lack and the uncertainty of experimental data might have hindered the development of accurate thermodynamic models for polyelectrolytes. In this work, the main phenomena of counterion condensation, complex formation and coacervate formation are discussed and considered for the further development of polyelectrolyte PC-SAFT (pePC-SAFT) as modeling framework in this work. The new development was then validated using experimental osmotic coefficients of aqueous polyelectrolyte solutions. Finally, liquid-liquid phase separation (LLPS) of complex coacervate systems (aqueous solutions containing oppositely charged polyions) were modeled with pePC-SAFT, and the results were in very good agreement with literature data.

{"title":"Molecular thermodynamics of complex coacervate systems. Part I: Modeling of polyelectrolyte solutions using pePC-SAFT","authors":"Moreno Ascani, Gabriele Sadowski, Christoph Held","doi":"10.1016/j.fluid.2024.114304","DOIUrl":"10.1016/j.fluid.2024.114304","url":null,"abstract":"<div><div>Rigorous molecular modeling of polyelectrolyte solutions is complicated by several intrinsic challenges of those systems, such as the strong charge correlation and the complex cocktail of short-range and long-range interactions, which span over a broad length scale. On the other hand, there is an increasing interest in understanding and designing polyelectrolyte systems in biology, life science, medicine, and (bio)chemical engineering. Thermodynamics of polyelectrolyte solutions is rather underexplored, and the difficulties in describing polyelectrolytes at the molecular level as well as the lack and the uncertainty of experimental data might have hindered the development of accurate thermodynamic models for polyelectrolytes. In this work, the main phenomena of counterion condensation, complex formation and coacervate formation are discussed and considered for the further development of polyelectrolyte PC-SAFT (pePC-SAFT) as modeling framework in this work. The new development was then validated using experimental osmotic coefficients of aqueous polyelectrolyte solutions. Finally, liquid-liquid phase separation (LLPS) of complex coacervate systems (aqueous solutions containing oppositely charged polyions) were modeled with pePC-SAFT, and the results were in very good agreement with literature data.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"591 ","pages":"Article 114304"},"PeriodicalIF":2.8,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Probing the energy landscapes and adsorption behavior of asphaltene molecules near the silica surface: Insights from molecular simulations

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-11-29 DOI: 10.1016/j.fluid.2024.114295

Shubham Chobe, Prashil Badwaik, Ateeque Malani

Enhanced oil recovery (EOR) is a promising solution to meet the increasing energy demands. However, the efficiency of EOR processes is hindered by the deposition and precipitation of heavy oil components, such as asphaltenes, at various stages of oil extraction. Therefore, a detailed understanding of asphaltene molecules (AMs)–rock interactions is important for designing novel solvents and enhancing the efficiency of existing solvents in oil recovery. Using molecular dynamics simulations, we have investigated the structural and energetic behavior of model AMs in dodecane solvent near the silica surface representing the sandstone reservoirs. We obtained the potential of mean force of AMs (containing three island-type and two archipelago-type AMs), calculated their adsorption–desorption barriers, and compared them among themselves and with solvent molecules. We found a competition between AMs and solvent, where AMs with higher configurational energy than the solvent molecules exhibit preferential surface adsorption. We observed that the heteroatom-surface interactions play a pivotal role in the adsorption of AMs, such that AMs with polar heteroatoms prefer to adsorb onto the surface. Further, the desorption barrier of AMs was found to be proportional to the number of hydrogen bonds formed. We observed that the AMs anchored to the surface through the aliphatic chains lie parallel, whereas those with heteroatom adopt an orientation nearly perpendicular to the surface.

{"title":"Probing the energy landscapes and adsorption behavior of asphaltene molecules near the silica surface: Insights from molecular simulations","authors":"Shubham Chobe, Prashil Badwaik, Ateeque Malani","doi":"10.1016/j.fluid.2024.114295","DOIUrl":"10.1016/j.fluid.2024.114295","url":null,"abstract":"<div><div>Enhanced oil recovery (EOR) is a promising solution to meet the increasing energy demands. However, the efficiency of EOR processes is hindered by the deposition and precipitation of heavy oil components, such as asphaltenes, at various stages of oil extraction. Therefore, a detailed understanding of asphaltene molecules (AMs)–rock interactions is important for designing novel solvents and enhancing the efficiency of existing solvents in oil recovery. Using molecular dynamics simulations, we have investigated the structural and energetic behavior of model AMs in dodecane solvent near the silica surface representing the sandstone reservoirs. We obtained the potential of mean force of AMs (containing three island-type and two archipelago-type AMs), calculated their adsorption–desorption barriers, and compared them among themselves and with solvent molecules. We found a competition between AMs and solvent, where AMs with higher configurational energy than the solvent molecules exhibit preferential surface adsorption. We observed that the heteroatom-surface interactions play a pivotal role in the adsorption of AMs, such that AMs with polar heteroatoms prefer to adsorb onto the surface. Further, the desorption barrier of AMs was found to be proportional to the number of hydrogen bonds formed. We observed that the AMs anchored to the surface through the aliphatic chains lie parallel, whereas those with heteroatom adopt an orientation nearly perpendicular to the surface.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"591 ","pages":"Article 114295"},"PeriodicalIF":2.8,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151872","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}

引用次数: 0

Vapor-liquid-liquid equilibria for the water + 1-butanol + CPME mixture

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-11-28 DOI: 10.1016/j.fluid.2024.114297

Gerard Alonso, Marcela Cartes, Andrés Mejía

In this contribution we have carried out vapor-liquid-liquid equilibrium (VLLE) determinations for the Water + 1-Butanol + cyclopenthyl methyl ether (CPME) mixture, where no previous information is reported. Measurements were performed with a commercial Fisher VLE/VLLE 602 equilibrium cell at 101.3 kPa and the Wisniak's L/K test is used to ensure the thermodynamic consistency for the two pairs of V-L^a and V-L^o phases at VLLE. Additionally, we have predicted the three-phase line of this system by performing modified multiphase flash calculations coupled with a phase stability restriction, where the system was modelled with the SAFT-VR-Mie equation of state. The VLLE of the ternary mixture was excellently predicted by only fitting binary interaction parameters to the phase equilibrium of each constituent binary mixture. This system has two partially miscible binaries in Water + 1-Butanol and Water + CPME, which makes the ternary liquid-liquid system a type II equilibrium envelope. The two binaries are connected through a zeotropic three-phase line.

引用次数: 0

Dissipative particle dynamics simulations identify structural properties and molecular clustering of alcohol-water mixtures 耗散粒子动力学模拟确定了醇-水混合物的结构特性和分子聚类

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-11-26 DOI: 10.1016/j.fluid.2024.114296

Hakan Camoglu , Gokhan Kacar

Modeling liquid structures of water and alcohol mixtures via coarse-grained simulations has been a challenge due to the loss of atomistic detail that are required to model the prevailing intermolecular interactions. Moreover, simulating the intrinsic structural ordering and inhomogeneities at mesoscopic-level has also been difficult due to the absence of these interactions. On the other hand, simulating these mixtures at a coarse-grained level is important since these liquids act as solvent in so many different applications. Therefore, in this work we strive to perform coarse-grained dissipative particle dynamics simulations (DPD) to model and simulate alcohol and water liquid mixtures. By using a recently developed DPD parameterization, we characterize their molecular-level structural inhomogeneity by quantifying the molecular clustering. In addition, the results regarding the structure by means of radial distribution functions, three-body angular distributions, and clustering behavior regarding maximum cluster size as a function of distance, cluster distance distribution function clearly show different levels of structural ordering for different mixtures. Moreover, we find that there is a significant difference between alcohol and water clustering behavior. For example, the distance at which clustering occurs in water molecules increases as the concentration of water decreases relative to alcohol. In addition, our results indicate that water and alcohol molecules at different concentrations display inhomogeneity, which agrees well with the literature and all-atom molecular dynamics simulations that are performed within the scope of this work. Hence, the prediction of the structural anomalies in alcohol-water mixtures shows that the employed DPD approach is able to capture the essential molecular structure of water and alcohols. The computational approach can be extended to study other hydrogen bonding soft matter to mimic their experimental structure in complex environments such as biological or synthetic solutions.

通过粗粒度模拟水和酒精混合物的液体结构一直是一个挑战，因为失去了模拟普遍的分子间相互作用所需的原子细节。此外，由于缺乏这些相互作用，在细观水平上模拟内在结构的有序和非均匀性也很困难。另一方面，在粗粒度水平上模拟这些混合物是很重要的，因为这些液体在许多不同的应用中充当溶剂。因此，在这项工作中，我们努力进行粗粒度耗散粒子动力学模拟（DPD）来模拟和模拟酒精和水的液体混合物。利用新近发展的DPD参数化方法，我们通过量化分子聚类来表征它们的分子水平结构不均匀性。此外，通过径向分布函数、三体角分布函数和最大簇大小作为距离和簇距离分布函数的聚类行为的分析结果清楚地表明，不同混合物的结构有序程度不同。此外，我们发现酒精和水的聚类行为存在显著差异。例如，当水相对于酒精的浓度降低时，水分子中发生聚集的距离就会增加。此外，我们的结果表明，不同浓度的水和酒精分子表现出不均匀性，这与文献和在本工作范围内进行的全原子分子动力学模拟非常一致。因此，对醇-水混合物结构异常的预测表明，所采用的DPD方法能够捕获水和醇的基本分子结构。该计算方法可以推广到其他氢键软物质的研究，以模拟它们在生物或合成溶液等复杂环境中的实验结构。

{"title":"Dissipative particle dynamics simulations identify structural properties and molecular clustering of alcohol-water mixtures","authors":"Hakan Camoglu , Gokhan Kacar","doi":"10.1016/j.fluid.2024.114296","DOIUrl":"10.1016/j.fluid.2024.114296","url":null,"abstract":"<div><div>Modeling liquid structures of water and alcohol mixtures <em>via</em> coarse-grained simulations has been a challenge due to the loss of atomistic detail that are required to model the prevailing intermolecular interactions. Moreover, simulating the intrinsic structural ordering and inhomogeneities at mesoscopic-level has also been difficult due to the absence of these interactions. On the other hand, simulating these mixtures at a coarse-grained level is important since these liquids act as solvent in so many different applications. Therefore, in this work we strive to perform coarse-grained dissipative particle dynamics simulations (DPD) to model and simulate alcohol and water liquid mixtures. By using a recently developed DPD parameterization, we characterize their molecular-level structural inhomogeneity by quantifying the molecular clustering. In addition, the results regarding the structure by means of radial distribution functions, three-body angular distributions, and clustering behavior regarding maximum cluster size as a function of distance, cluster distance distribution function clearly show different levels of structural ordering for different mixtures. Moreover, we find that there is a significant difference between alcohol and water clustering behavior. For example, the distance at which clustering occurs in water molecules increases as the concentration of water decreases relative to alcohol. In addition, our results indicate that water and alcohol molecules at different concentrations display inhomogeneity, which agrees well with the literature and all-atom molecular dynamics simulations that are performed within the scope of this work. Hence, the prediction of the structural anomalies in alcohol-water mixtures shows that the employed DPD approach is able to capture the essential molecular structure of water and alcohols. The computational approach can be extended to study other hydrogen bonding soft matter to mimic their experimental structure in complex environments such as biological or synthetic solutions.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"590 ","pages":"Article 114296"},"PeriodicalIF":2.8,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746703","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}

引用次数: 0

Exploring hydrophobic eutectic solvents based on raspberry ketone 探索基于覆盆子酮的疏水共晶溶剂

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-11-17 DOI: 10.1016/j.fluid.2024.114287

Bárbara C. Jesus , José M. Pires , Hugo Marques , Isabel M. Marrucho

Hydrophobic Eutectic Solvents (HES) have been drawing attention over the last decade, since they offer a green possibility of replacing volatile organic solvents derived from fossil sources. This work focuses on the development of new HES based on raspberry ketone (RK). COSMO-RS (COnductor-like Screening MOdel for Real Solvents) was used to screen hydrophobic compounds to be used in HES formation with RK. Afterwards, the solid-liquid equilibrium was experimentally measured for RK and four selected compounds, DL-Menthol, Thymol, Lidocaine and Flavone, using visual turbidimetry and Differential Scanning Calorimetry. UNIversal QUAsi-Chemical (UNIQUAC) model was used to model the experimental data and validate both the experimental data and COSMO-RS results. Thermophysical properties, density and viscosity, of the prepared HES were measured, in a temperature range between 40 °C and 80 °C, for selected compositions that were liquid at room temperature. The polarity of these liquid at room temperature HES was also quantified using Kamlet-Taft and betaine dye scales. Finally, the water mutual solubility was also experimentally measured so that conclusions can be drawn about their HES hydrophobicity.

疏水性共晶溶剂（HES）在过去十年中一直备受关注，因为它们提供了一种替代化石来源挥发性有机溶剂的绿色可能性。这项工作的重点是开发基于覆盆子酮（RK）的新型 HES。COSMO-RS （Connductor-like Screening MOdel for Real Solvents）被用来筛选疏水性化合物，以用于与 RK 形成 HES。随后，使用目视浊度法和差示扫描量热法对 RK 和四种选定化合物（DL-薄荷醇、百里酚、利多卡因和黄酮）的固液平衡进行了实验测量。使用 UNIversal QUAsi-Chemical (UNIQUAC) 模型对实验数据进行建模，并对实验数据和 COSMO-RS 结果进行验证。在 40 °C 至 80 °C 的温度范围内，测量了所制备 HES 的热物理性质、密度和粘度，所选成分在室温下为液态。此外，还使用 Kamlet-Taft 和甜菜碱染料标度对这些室温液态 HES 的极性进行了量化。最后，还对水的互溶性进行了实验测量，从而得出关于 HES 疏水性的结论。

{"title":"Exploring hydrophobic eutectic solvents based on raspberry ketone","authors":"Bárbara C. Jesus , José M. Pires , Hugo Marques , Isabel M. Marrucho","doi":"10.1016/j.fluid.2024.114287","DOIUrl":"10.1016/j.fluid.2024.114287","url":null,"abstract":"<div><div>Hydrophobic Eutectic Solvents (HES) have been drawing attention over the last decade, since they offer a green possibility of replacing volatile organic solvents derived from fossil sources. This work focuses on the development of new HES based on raspberry ketone (RK). COSMO-RS (COnductor-like Screening MOdel for Real Solvents) was used to screen hydrophobic compounds to be used in HES formation with RK. Afterwards, the solid-liquid equilibrium was experimentally measured for RK and four selected compounds, DL-Menthol, Thymol, Lidocaine and Flavone, using visual turbidimetry and Differential Scanning Calorimetry. UNIversal QUAsi-Chemical (UNIQUAC) model was used to model the experimental data and validate both the experimental data and COSMO-RS results. Thermophysical properties, density and viscosity, of the prepared HES were measured, in a temperature range between 40 °C and 80 °C, for selected compositions that were liquid at room temperature. The polarity of these liquid at room temperature HES was also quantified using Kamlet-Taft and betaine dye scales. Finally, the water mutual solubility was also experimentally measured so that conclusions can be drawn about their HES hydrophobicity.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"590 ","pages":"Article 114287"},"PeriodicalIF":2.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702093","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}

引用次数: 0

Non-equilibrium characteristics and regulation methods of methane hydrate nucleation on the substrate surface 基质表面甲烷水合物成核的非平衡特性和调节方法

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-11-17 DOI: 10.1016/j.fluid.2024.114288

Shuangshuang Meng, Yuhua Xiao, Zhaoliang Wang

The synthesis process of methane hydrate exhibits strong non-equilibrium phenomena at all stages, with the nucleation stage being the most prominent. In this study, we used molecular dynamics simulations to investigate the spontaneous synthesis of methane hydrate on solid surfaces, focusing on the mass transfer non-equilibrium characteristics during the nucleation stage. From the overall perspective of nucleation events, we applied the Onsager hypothesis and introduced normalized autocorrelation functions to analyze the fluctuation-dissipation characteristics of hydrate cage structures on different substrate surfaces. We also examined the relationship between the orderliness of water molecules forming the cages and the solubility and diffusion of guest molecules. By comparing the effects of temperature and the presence of SDS and THF additives, we regulated the non-equilibrium characteristics during nucleation. The results indicate that nucleation on aluminum surfaces exhibits stronger non-equilibrium characteristics; there is a synergy between the components forming the hydrate and the overall fluctuation characteristics; lowering the temperature inhibits the non-equilibrium characteristics of the nucleation process but also reduces the number of nucleation events; the addition of additives effectively enhances the non-equilibrium characteristics, with the effect being more pronounced when SDS is in the gas phase, shortening the fluctuation period and relaxation time by 90.2 % and 66.3 %, respectively. This study demonstrates the mass transfer-driven non-equilibrium characteristics of the spontaneous nucleation of methane hydrates on solid surfaces and provides regulatory methods, contributing to a deeper understanding of the synthesis mechanism of hydrates.

甲烷水合物的合成过程在各个阶段都表现出强烈的非平衡现象，其中成核阶段最为突出。在本研究中，我们利用分子动力学模拟研究了甲烷水合物在固体表面的自发合成过程，重点研究了成核阶段的传质非平衡特性。我们从成核事件的整体角度出发，应用 Onsager 假设并引入归一化自相关函数，分析了不同基底表面上水合物笼状结构的波动-消散特征。我们还研究了形成笼状结构的水分子的有序性与客体分子的溶解度和扩散之间的关系。通过比较温度以及 SDS 和 THF 添加剂的影响，我们调节了成核过程中的非平衡特性。结果表明，铝表面的成核过程表现出更强的非平衡特性；形成水合物的成分与整体波动特性之间存在协同作用；降低温度会抑制成核过程的非平衡特性，但同时也会减少成核事件的数量；添加添加剂可有效增强非平衡特性，当 SDS 处于气相时效果更明显，波动周期和弛豫时间分别缩短了 90.2% 和 66.3%。这项研究证明了固体表面甲烷水合物自发成核的传质驱动非平衡特性，并提供了调节方法，有助于加深对水合物合成机理的理解。

{"title":"Non-equilibrium characteristics and regulation methods of methane hydrate nucleation on the substrate surface","authors":"Shuangshuang Meng, Yuhua Xiao, Zhaoliang Wang","doi":"10.1016/j.fluid.2024.114288","DOIUrl":"10.1016/j.fluid.2024.114288","url":null,"abstract":"<div><div>The synthesis process of methane hydrate exhibits strong non-equilibrium phenomena at all stages, with the nucleation stage being the most prominent. In this study, we used molecular dynamics simulations to investigate the spontaneous synthesis of methane hydrate on solid surfaces, focusing on the mass transfer non-equilibrium characteristics during the nucleation stage. From the overall perspective of nucleation events, we applied the Onsager hypothesis and introduced normalized autocorrelation functions to analyze the fluctuation-dissipation characteristics of hydrate cage structures on different substrate surfaces. We also examined the relationship between the orderliness of water molecules forming the cages and the solubility and diffusion of guest molecules. By comparing the effects of temperature and the presence of SDS and THF additives, we regulated the non-equilibrium characteristics during nucleation. The results indicate that nucleation on aluminum surfaces exhibits stronger non-equilibrium characteristics; there is a synergy between the components forming the hydrate and the overall fluctuation characteristics; lowering the temperature inhibits the non-equilibrium characteristics of the nucleation process but also reduces the number of nucleation events; the addition of additives effectively enhances the non-equilibrium characteristics, with the effect being more pronounced when SDS is in the gas phase, shortening the fluctuation period and relaxation time by 90.2 % and 66.3 %, respectively. This study demonstrates the mass transfer-driven non-equilibrium characteristics of the spontaneous nucleation of methane hydrates on solid surfaces and provides regulatory methods, contributing to a deeper understanding of the synthesis mechanism of hydrates.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"590 ","pages":"Article 114288"},"PeriodicalIF":2.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702090","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}

引用次数: 0

Natural gas storage in hydrates in the presence of thermodynamic hydrate promoters: Review and experimental investigation

IF 2.8 3区工程技术 Q3 CHEMISTRY, PHYSICAL

Fluid Phase Equilibria

Pub Date : 2024-11-17 DOI: 10.1016/j.fluid.2024.114286

Yu Wei , Joshua Worley , Luis E. Zerpa , Yu-Chien (Alice) Chien , Derek Dunn-Rankin , Michael T. Kezirian , Carolyn A. Koh

Natural gas (NG), the cleanest fossil fuel, is playing an increasingly important role in the current energy supply. However, the safe storage and transportation of flammable NG is a long-standing challenge. Furthermore, NG emission has a stronger per molecule greenhouse effect on the environment than CO₂. Therefore, efficient and effective methods of NG storage and transportation are needed. Storing NG in the form of gas hydrate offers advantages over common compression or liquefaction methods, but the thermodynamic conditions required for gas hydrate formation hinder the large-scale application of solidified natural gas (SNG) technology. This work presents a review of phase equilibrium conditions of gas hydrates formed by greenhouse gases including CH₄, CO₂ and NG in the presence of thermodynamic hydrate promoters. This study uses available thermodynamic software to calculate gas hydrate phase equilibrium using different Equations of State (EoS). We include an experimental investigation using a 2 L autoclave reactor to evaluate the effect of mass transfer, the presence of cyclopentane as a thermodynamic promoter, and the level of subcooling on the NG hydrate formation kinetics. The results show that: 1) Tetrahydrofuran and cyclopentane generally have the strongest thermodynamic-promoting effect; 2) Thermodynamic promotion of cyclopentane on NG hydrate is validated experimentally; 3) NG hydrate formation kinetics is greatly influenced by mechanical stirring (mass transfer), cyclopentane as a co-former and its concentration and subcooling; 4) At high subcooling, cyclopentane-promoted systems show a significantly improved gas storage capacity than the baseline sample; and 5) NG hydrate particles have a size distribution of hundreds of microns under current experimental conditions. This study offers new insight into NG hydrate formation thermodynamics and kinetics that has application to SNG technology.

{"title":"Natural gas storage in hydrates in the presence of thermodynamic hydrate promoters: Review and experimental investigation","authors":"Yu Wei , Joshua Worley , Luis E. Zerpa , Yu-Chien (Alice) Chien , Derek Dunn-Rankin , Michael T. Kezirian , Carolyn A. Koh","doi":"10.1016/j.fluid.2024.114286","DOIUrl":"10.1016/j.fluid.2024.114286","url":null,"abstract":"<div><div>Natural gas (NG), the cleanest fossil fuel, is playing an increasingly important role in the current energy supply. However, the safe storage and transportation of flammable NG is a long-standing challenge. Furthermore, NG emission has a stronger per molecule greenhouse effect on the environment than CO<sub>2</sub>. Therefore, efficient and effective methods of NG storage and transportation are needed. Storing NG in the form of gas hydrate offers advantages over common compression or liquefaction methods, but the thermodynamic conditions required for gas hydrate formation hinder the large-scale application of solidified natural gas (SNG) technology. This work presents a review of phase equilibrium conditions of gas hydrates formed by greenhouse gases including CH<sub>4</sub>, CO<sub>2</sub> and NG in the presence of thermodynamic hydrate promoters. This study uses available thermodynamic software to calculate gas hydrate phase equilibrium using different Equations of State (EoS). We include an experimental investigation using a 2 L autoclave reactor to evaluate the effect of mass transfer, the presence of cyclopentane as a thermodynamic promoter, and the level of subcooling on the NG hydrate formation kinetics. The results show that: 1) Tetrahydrofuran and cyclopentane generally have the strongest thermodynamic-promoting effect; 2) Thermodynamic promotion of cyclopentane on NG hydrate is validated experimentally; 3) NG hydrate formation kinetics is greatly influenced by mechanical stirring (mass transfer), cyclopentane as a co-former and its concentration and subcooling; 4) At high subcooling, cyclopentane-promoted systems show a significantly improved gas storage capacity than the baseline sample; and 5) NG hydrate particles have a size distribution of hundreds of microns under current experimental conditions. This study offers new insight into NG hydrate formation thermodynamics and kinetics that has application to SNG technology.</div></div>","PeriodicalId":12170,"journal":{"name":"Fluid Phase Equilibria","volume":"591 ","pages":"Article 114286"},"PeriodicalIF":2.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151813","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}

引用次数: 0