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Temperature-dependent solubility of Rebaudioside A in methanol/ethanol and ethyl acetate mixtures:Experimental measurements and thermodynamic modeling

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Chinese Journal of Chemical Engineering 2024年第8期72卷 164-176页

作者： Zhenguang Liu Zexiang Ding Yifeng Cao Baojian Liu Qiwei Yang Zhiguo Zhang Qilong Ren Zongbi Bao Key Laboratory of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310058China Institute of Zhejiang University-Quzhou Quzhou 324000China

The equilibrium solubility of Rebaudioside A(Reb A)FormⅡin binary mixtures of methanol/ethanol and ethyl acetate was quantitatively determined within the temperature range of 283.15—328.15 K at ambient *** experimental findings indicate a positive correlation between the solubility of Reb A(FormⅡ)and both the temperature and the methanol/ethanol content in the solvent *** describe the solubility data,six distinct models were employed:the modified Apelblat equation,theλh model,the combined nearly ideal binary solvent/Redlich—Kister(CNIBS/R—K)model,the van't HoffJouyban-Acree(VJA)model,the Apelblat-Jouyban-Acree(AJA)model,and the non-random two-liquid(NRTL)*** combined nearly ideal binary solvent/Redlich—Kister model exhibited the most precise fit for solubility in methanol+ethyl acetate mixtures,reflected by an average relative deviation(ARD)of 0.0011 and a root mean square deviation(RMSD)of 12×10^(-7).Conversely,for ethanol+ethyl acetate mixtures,the modified Apelblat equation provided a superior correlation(ARD=0.0014,RMSD=4×10^(-7)).Furthermore,thermodynamic parameters associated with the dissolution of Reb A(FormⅡ),including enthalpy,entropy,and the Gibbs energy change,were inferred from the *** findings underscore that the dissolution process is predominantly endothermic across the solvent systems ***,the entropy changes appear to have a significant influence on the Gibbs free energy associated with the dissolution of Reb A(FormⅡ),suggesting that entropic factors may play a pivotal role in the studied systems.

关键词： Rebaudioside A Solubility thermodynamic modeling Dissolution Binary solvent

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thermodynamic modeling of the La-Mg-Y system and Mg-based alloys database

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Rare Metals 2006年第5期25卷 492-500页

作者： DU Zhenmin GUO Cuiping LI Changrong ZHANG Weijing Department of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

As an example of the La-Mg-Y system, the method how to set up the themaodynamic model of individual phases was introduced in the process of thermodynamic optimization. The solution phases （liquid, body-centered cubic, face-centered cubic, hexagonal close-packed and double hexagonal close-packed） were modeled with the Redlich-Kister equation. The compound energy model has been used to describe the thermodynamic functions of the intermetallic compounds in the La-Mg-Y systems. The compounds Mg2Y, Mg24Y5, Mg12La, Mg17La2, Mg41Las, Mg3La and Mg2La in the La-Mg-Y system were treated as the formulae （Mg,Y）2（La,Mg,Y）, Mg24（La,Mg,Y）4Y, Mg12（La, Y）, Mg17（La,Y）2, Mg41（La,Y）5, Mg3（La,Mg,Y） and Mg2（La, Y）, respectively. A model （La, Mg,Y）0.5（La,Mg,Y）0.5 was applied to describe the compound MgM formed by MgLa and MgY in order to cope with the order-disorder transition between body-centered cubic solution （A2） and MgM with CsCl-type structure （B2） in the La-Mg-Y system. The Gibbs energies of individual phases were optimized in the La-Mg, La-Y and La-Mg-Y systems by CALPHAD technique. The projection of the liquidus surfaces for the La-Mg-Y system was predicted. The Mg-based alloys database including 36 binary and 15 ternary systems formed by Mg, Al, Cu, Ni, Mn, Zn and rare earth elements was set up in SGTE standard.

关键词： La-Mg-Y system thermodynamic modeling CALPHAD technique order-disorder transition Mg-based alloys database

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thermodynamic modeling of gas solubility in aqueous sodium chloride solution

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Chinese Journal of Chemical Engineering 2021年第10期34卷 184-195页

作者： Li Sun Jierong Liang College of Mechanical and Electrical Engineering Hohai UniversityChangzhou 213022China Department of Chemical and Biochemical Engineering Technical University of Denmark2800 Kgs.LyngbyDenmark Department of Energy Conversion and Storage Technical University of Denmark2800 Kgs.LyngbyDenmark

An electrolyte Equation of State is presented by combining the Cubic Plus Association Equation of State,Mean Spherical Approximation and the Born *** new model uses experimental relative static permittivity,intend to predict well the activity coefficients of individual ions(ACI)and liquid densities of aqueous *** new model is applied to model water+Na Cl binary system and water+gas+Na Cl ternary *** cation/anion-water interaction parameters of are obtained by fitting the experimental data of ACI,mean ionic activity coefficients(MIAC)and liquid densities of water+Na Cl binary *** cation/anion-gas interaction parameters are obtained by fitting the experimental data of gas solubilities in aqueous Na Cl *** modeling results show that this new model can correlate well with the phase equilibrium and volumetric *** gas,predictions for ACI,MIAC,and liquid densities present relative average deviations of 1.3%,3.6%and 1.4%compared to experimental reference *** most gas-containing systems,predictions for gas solubilities present relative average deviations lower than 7.0%.Further,the contributions of ACI,and salting effects of Na Cl on gases are analyzed and discussed.

关键词： thermodynamic modeling Liquid density Activity coefficients of individual ions Gas solubility

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thermodynamic modeling and elemental migration for the early stage of rodingitization:An example from the Xialu massif of the Xigaze ophiolite,southern Tibet

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Geoscience Frontiers 2021年第3期12卷 557-576页

作者： Wen-Yong Duan Xu-Ping Li Ze-Li Wang Shuang Chen Guang-Ming Sun Ling-Quan Zhao Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals Shandong University of Science and TechnologyQingdao 266590China Institute of Geology Mineralogy and GeophysicsFaculty of GeosciencesRuhr-University Bochum44780 BochumGermany

The analysis of early stage rodingite from the ultramafic rocks of the Xialu Massif in the Xigaze Ophiolite,Tibet,in China shows that the rodingitization involved continuous changes in fluid composition during different stages of *** early stage prehnite-bearing rodingite was produced at low pressures and temperatures along extensional *** of rodingite were collected along a profile from the center to the margin of a rodingitized intrusive igneous rock(^10 m×30 m),and they record wide variations in bulk composition,mineralogy,and *** mineral assemblages,from center to margin,vary from(1)relics of primary clinopyroxene(Cpx_(r))and primary amphibole(Amp_(r))+newly formed late amphibole(Act)+primary plagioclase(Pl_(r))+clinozoisite+prehnite+albite+chlorite+titanite+ilmenite(R1 rodingite),through(2)relics of primary clinopyroxene(Cpx_(r))+newly formed late clinopyroxene(Cpx_(n))+primary and late amphiboles(Amp_(r)+Act)+clinozoisite+prehnite+albite+chlorite+titanite(R2 rodingite),to(3)newly formed late clinopyroxene(Cpx_(n))and amphibole(Act)+clinozoisite+prehnite+albite+chlorite+titanite(R3 rodingite).As a result of the metasomatic process of rodingitization,the content of CaO in the whole rock chemical composition from R1 to R3 increases,SiO_(2) decreases,and Na_(2)O+K_(2)O is almost completely *** diagrams show enrichments in large ion lithophile elements such as Rb,Cs,Ba,and Pb as well as Ni during *** central part of the rodingitized intrusion(R1 rodingite)was only slightly affected by *** the other hand,the contents of the rare earth elements(REEs),high field strength elements(HFSEs;***,Nb,Ta,Hf,and Y),and some highly compatible elements such as Cr and Sc decreased slightly during *** modeling based on equilibrium mineral assemblages indicates that the rodingite of the Xialu Massif formed in an H_(2)O-saturated,CO_(2)-rich *** estimated conditions o

关键词： Early stage rodingitization Element migration thermodynamic modeling Xialu Massif Xigaze Ophiolite Southern Tibet

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thermodynamic modeling as a Strategy for Casting High Alloy Steels

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Journal of Iron and Steel Research International 2009年第5期16卷 29-31页

作者： Peri Reddy V S Raman Sankaranarayanan Department of Metallurgical and Materials Engineering National Institute of Technology

Strategies based on thermodynamic calculations can be used to overcome the problems associated with oxides encountered in steel plant operations, which can lead to certain difficulties in the process such as clogging of submerged entry nozzle during continuous casting. Approaches to producing high alloy steels by continuous casting have been taken. One of the strategies to avoid the oxidation of chromium is to add a small amount of other elements （subject to other constraints）, which do not cause subsequent problems. The problem has been studied using the Thermo-CalcR software, with related databases; and the results obtained for different process conditions or generic compositions have been presented.

关键词： alloy steel continuous casting clogging slag thermodynamic modeling

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thermodynamic modeling of Deoxidation Products and Inclusion Chemistry in Mn/Si Killed Tire-Cord Steel

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Journal of Iron and Steel Research International 2011年第S2期18卷 389-393页

作者： Akula DurgaVara Prasad Sankara Raman Sankaranarayanan Dept. of Metallurgical and Materials Engineering National Institute of Technology Tiruchirappalli Tiruchirappalli 620015 Tamil Nadu India

The present work deals with thermodynamic modeling of oxide systems, in the context of slags and inclusions in steelmaking. The work has emphasis on oxides encountered during the production of tire – cord steel. Control of inclusion chemistry and variation in eutectic temperature and eutectic composition of MnO-Al2O3-SiO2 slag system have been studied, using Thermo-CalcR software. Relatively low liquidus temperatures are obtained for ratio of MnO / SiO2 = 0.5 - 1.5 and Al2O3 content from 10 - 20 mass%. It has been observed that the addition of Alumina leads to further increase in the liquidus temperature. The stability of inclusions is analyzed in terms of free energy values of related slag systems; and an appropriate minimum of Gibbs free energy value of slag phase observed at around 50 ppm of Oxygen. The observations could not be verified using thermodynamic experiments, but have been compared with findings in the open literature.

关键词： thermodynamic modeling tire – cord steel inclusion engineering deoxidation thermo-calcR oxide slags

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First-principles Calculation Assisted thermodynamic modeling of Ti-Co-Cu Ternary System

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Journal of Materials Science & Technology 2010年第4期26卷 317-326页

作者： Y.J. Yang X.M. Tao W.J. Zhu Z.H. Long H.S. Liu Z.P. Jin School of Materials Science and Engineering Central South University Changsha 410083 China Key Lab of Non-ferrous Metal Science and Engineering Ministry of Education Changsha 410081 China

thermodynamic assessment of Ti-Co-Cu ternary system has been carried out by combining first-principle calculation and CALPHAD method. Firstly, formation enthalpies of stable and hypothesized compounds were calculated by first-principles method. Then, based on reported experimental information, a thermodynamic description of the Ti-Co-Cu ternary system was performed. Solution phases were treated as substitutional solutions of which excess Gibbs energies were formulated by Redlich-Kister polynomial, and the intermediate phases were described with sublattice models. All measured isothermal sections were reasonably reproduced. In addition, liquidus projection of this ternary system was further calculated, which may be useful for relevant materials processing.

关键词： First-principle CALPHAD thermodynamic modeling

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Fluid-rock interactions leading to the formation of the epithermal Ag-Pb-Zn veins:A perspective of thermodynamic modeling

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Fundamental Research 2023年第4期3卷 570-578页

作者： Degao Zhai School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China

Although vein-type silver-lead-zinc ore deposits have been extensively studied,the factors controlling their formation are still poorly understood and their genesis is a matter of ongoing *** this contribution,I present new mineralogical data and the results of thermodynamic modeling that constrain the conditions of metal transport and deposition for the Aerhada epithermal Pb-Zn-Ag deposit(reserves of>1,000 t Ag@58 g/t and 1.0 Mt Pb+Zn@5.2%)in NE *** primary paragenetic stages have been identified,the second of which(Stage II)is the main base metal and silver ***,argentite,pyrargyrite,and canfieldite are the main Ag-bearing minerals and are spatially associated with an alteration assemblage of quartz-muscovite±chlorite±*** textures and evidence of compositional heterogeneity for freibergite suggest that its decomposition may have redistributed the Ag and contributed in part to the high Ag grade ores in the *** calculations indicate that there was extensive silver ore deposition from a strongly reducing(e.g.,∆log fO_(2)(HM)ofmodeling showed that the sole evolution of a magmatic-derived fluid is capable of forming the large Ag-Pb-Zn veins via fluid-rock interactions,which is contrary to the conclusions of some other studies that the mixture of an externally derived fluid is required to explain their *** genetic model for Ag-Pb-Zn ore formation developed in this study is applicable to other polymetallic vein-type deposits in comparable geological settings elsewhere.

关键词： Epithermal deposit Ag-Pb-Zn veins Metal transport thermodynamic modeling NE China

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Phase equilibrium data prediction and process optimizationin butadiene extraction process

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Chinese Journal of Chemical Engineering 2024年第7期71卷 1-12页

作者： Baowei Niu Yanjie Yi Yuwen Wei Fuzhen Zhang Lili Wang Li Xia Xiaoyan Sun Shuguang Xiang Institute of Process System Engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China

In response to the lack of reliable physical parameters in the process simulation of the butadiene extraction,a large amount of phase equilibrium data were collected in the context of the actual process of butadiene production by *** accuracy of five prediction methods,UNIFAC(UNIQUAC Functional-group Activity Coefficients),UNIFAC-LL,UNIFAC-LBY,UNIFAC-DMD and COSMO-RS,applied to the butadiene extraction process was verified using partial phase equilibrium *** results showed that the UNIFAC-DMD method had the highest accuracy in predicting phase equilibrium data for the missing ***-RS-predicted multiple systems showed good accuracy,and a large number of missing phase equilibrium data were estimated using the UNIFAC-DMD method and COSMO-RS *** predicted phase equilibrium data were checked for *** NRTL-RK(non-Random Two Liquid-Redlich-Kwong Equation of State)and UNIQUAC thermodynamic models were used to correlate the phase equilibrium *** device simulations were used to verify the accuracy of the thermodynamic model applied to the butadiene extraction *** simulation results showed that the average deviations of the simulated results using the correlated thermodynamic model from the actual values were less than 2%compared to that using the commercial simulation software,Aspen Plus and its *** average deviation was much smaller than that of the simulations using the Aspen Plus database(>10%),indicating that the obtained phase equilibrium data are highly accurate and *** best phase equilibrium data and thermodynamic model parameters for butadiene extraction are *** improves the accuracy and reliability of the design,optimization and control of the process,and provides a basis and guarantee for developing a more environmentally friendly and economical butadiene extraction process.

关键词： Butadiene extraction Phase equilibrium data Prediction methods thermodynamic modeling Process simulation

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The contribution of solid-state chemistry in the determination of multicomponent phase diagrams

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Rare Metals 2006年第5期25卷 576-581页

作者： Jean Claude Tedenac Franck Gascoin Didier Ravot Université Montpellier 2 LPMC-UMR-CNRS-5617 MontpellierFrance

For a long period of time, the determination of phase diagrams was only supported by experiments related to thermal effects or thermodynamic measurements： thermal analysis, calorimetric measurements, vapor pressures, and EMF measurements. As a matter of fact, solid-solid transformations were not so accurately determined and could not be taken into account in the system＇s analysis. First, X-ray diffraction methods were used as a support for the thermal analysis. Second, the implementation of novel tools in structural analysis （for example, the Rietveld method） has permitted to increase the knowledge of phase stability. Finally, modeling the phases using a Calphad method needed increasingly more structural results to determine and better understand the phase diagrams. On the other hand, the Calphad method has been widely developed for metallic systems, for oxide systems, and in the past 10 years, for some semi-conductor systems, for example, gallium arsenide, cadmium telluride, and lead telluride systems. In such applications, it is very important to bring point defects in the modeling of the phases to map the defects as a function of the chemical composition. Owing to its complexity, this characteristic, the knowledge of which is crucial for the understanding and the control of potential physical applications, was ignored in the previous assessment of semi-conductor systems.

关键词： thermodynamic modeling solid-state chemistry phase diagram

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