Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)...Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)K and at ambient pressure(81.5 kPa).From the experimental data,excess molar volume(V_(m)~E),thermal expansion coefficients(α),deviations in isentropic compressibility(Δκ_(S)),viscosity(Δ_η),and refractive index(Δn_(D))were calculated.These values were then correlated using the Redlich-Kister polynomial equation,with fitting coefficients and standard deviations determined.Additionally,the Prigogine-Flory-Patterson(PFP)theory and the Extended Real Associated Solution(ERAS)model were employed to correlate the excess molar volume,while the Perturbed Chain Statistical Associating Fluid Theory(PC-SAFT)was used to predict the density of mixtures.展开更多
The phase equilibria relationship of the system RbCl-PEG6000-H2O were investigated at temperatures of 288.2,298.2,and 308.2 K,the compositions of solid-liquid equilibria(SLE)and liquid-liquid equilibria(LLE)were deter...The phase equilibria relationship of the system RbCl-PEG6000-H2O were investigated at temperatures of 288.2,298.2,and 308.2 K,the compositions of solid-liquid equilibria(SLE)and liquid-liquid equilibria(LLE)were determined.The complete phase diagrams,binodal curve diagrams,and tie-line diagrams were all plotted.Results show that both solid-liquid equilibria and liquid-liquid equilibria relationships at each studied temperature.The complete phase diagrams at 288.2 K,298.2 K and 308.2 K consist of six phase regions:unsaturated liquid region(L),two saturated solutions with one solid phase of RbCl(L_S),one saturated liquid phase with two solid phases of PEG6000 and RbCl(2S+L),an aqueous two-phase region(2L),and a region with two liquids and one solid phase of RbCl(2L_S).With the increase in temperature,the layering ability of the aqueous two-phase system increases,and both regions(2L)and(2L_S)increase.The binodal curves were fitted using the nonlinear equations proposed by Mistry,Hu,and Jayapal.Additionally,the tie-line data were correlated with the Othmer-Tobias,Bancroft,Hand,and Bachman equations.The liquid-liquid equilibria at 288.2 K,298.2 K and 308.2 K were calculated using the NRTL model.The findings confirm that the experimental and calculated values are in close agreement,demonstrating the model’s effectiveness in representing the system’s behavior.展开更多
The article considers a relaxation of the water/polypropylene glycol-425 solution with a lower critical solution temperature(LCST)following its pulsed superheating concerning liquid-liquid and liquid-vapor equilibrium...The article considers a relaxation of the water/polypropylene glycol-425 solution with a lower critical solution temperature(LCST)following its pulsed superheating concerning liquid-liquid and liquid-vapor equilibrium lines,as well as the liquid-liquid spinodal.Superheating was performed using the pulsed heat generation method in a micro-sized wire probe.The main heating mode was the constant(over the pulse length)power mode.Characteristic heating rates ranged from 0.05×10^(5) to 2×10^(5) K/s,while the degree of superheating concerning the spinodal was up to 200 K.The temperature of spontaneous boiling-up and the amplitude of the corresponding signal were monitored as functions of the heating rate set by the power value.The results demonstrate an example of the interaction of liquidliquid and liquid-vapor phase transitions,as well as the spinodal decomposition of a solution with LCST against the background of its unstable states.We proposed a physical model to explain the minimum spontaneous boiling-up temperature revealed within a certain range of heating rates,which is not typical of completely miscible solutions.Further research will focus on establishing a general criterion for the possibility of spinodal decomposition of such solutions under the conditions of rapid heating.展开更多
An equation of state(EOS)was obtained that accurately describes the thermodynamics of the system H_(2)O–CO_(2) at temperatures of 50–350°C and pressures of 0.2–3.5 kbar.The equation is based on experimental da...An equation of state(EOS)was obtained that accurately describes the thermodynamics of the system H_(2)O–CO_(2) at temperatures of 50–350°C and pressures of 0.2–3.5 kbar.The equation is based on experimental data on the compositions of the coexisting liquid and gas phases and the Van Laar model,within which the values of the Van Laar parameters A12 and A21 were found for each experimental P-T point.For the resulting sets A12(P,T),A21(P,T),approximation formulas describing the dependences of these quantities on temperature and pressure were found and the parameters contained in the formulas were fitted.This two-stage approach made it possible to obtain an adequate thermodynamic description of the system,which allows,in addition to determining the phase state of the system(homogeneous or heterogeneous),to calculate the excess free energy of mixing of H_(2)O and CO_(2),the activities of H_(2)O and CO_(2),and other thermodynamic characteristics of the system.The possibility of such calculations creates the basis for using the obtained EOS in thermodynamic models of more complicated fluid systems in P-T conditions of the middle and upper crust.These fluids play an important role in many geological processes including the transport of ore matter and forming hydrothermal ore deposits,in particular,the most of the world’s gold deposits.The knowledge of thermodynamics of these fluids is important in the technology of drilling oil and gas wells.In particular,this concerns the prevention of precipitation of solid salts in the well.展开更多
SiO_(2)is the main component of gangue in sinters and a crucial constituent in the formation of the SiO_(2)–Fe_(2)O_(3)–Cao(SFC)system.The non-isothermal crystallization kinetics of the SFC system were investigated ...SiO_(2)is the main component of gangue in sinters and a crucial constituent in the formation of the SiO_(2)–Fe_(2)O_(3)–Cao(SFC)system.The non-isothermal crystallization kinetics of the SFC system were investigated using differential scanning calorimetry.The crystallization process of SFC was studied under different cooling rates(5,10,15,and 20 K/min),and the crystalline phases and microstructures of the SFC crystals were verified through X-ray diffraction and scanning electron microscopy.The results indicate that when the SiO_(2)content is 2 wt.%,increasing the cooling rate promotes the precipitation of CaFe_(2)O_(4)(CF)in the SFC system,thereby inhibiting the precipitation of Ca_(2)Fe_(2)O_(5)(C_(2)F).In contrast to the Cao–Fe_(2)O_(3)(C–F)system,the addition of SiO_(2)does not alter the precipitation mechanisms of C_(2)F and CF.By further adding SiO_(2),the precipitation of Ca_(2)Sio_(4)(C_(2)S)significantly increases.Simultaneously,the Cao content in the liquid phase decreases.This leads to the crystallization process of the CF_(4)S(4 wt.%Sio_(2))system bypassing the precipitation of C_(2)F and directly forming CF and CaFe_(4)O_(7)(CF_(2)).In the case of the CF_(8)S(8 wt.%SiO_(2))system,the crystallization process skips the precipitation of C_(2)F and CF,directly yielding CF_(2).The crystallization process of both CF_(2)S(2 wt.%Sio_(2))and CF is similar,comprising two reaction stages.The Ozawa method was used to calculate the activation energy for the crystallization of C_(2)F and CF as-329 and-419 kJ/mol,respectively.Analysis using the Malek method reveals model functions for both stages.展开更多
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 pressure.The ...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 pressure.The 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 system.To 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)model.The 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 data.The findings underscore that the dissolution process is predominantly endothermic across the solvent systems examined.Notably,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.展开更多
基金Bu-Ali Sina University for providing financial support for conducting this study。
文摘Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)K and at ambient pressure(81.5 kPa).From the experimental data,excess molar volume(V_(m)~E),thermal expansion coefficients(α),deviations in isentropic compressibility(Δκ_(S)),viscosity(Δ_η),and refractive index(Δn_(D))were calculated.These values were then correlated using the Redlich-Kister polynomial equation,with fitting coefficients and standard deviations determined.Additionally,the Prigogine-Flory-Patterson(PFP)theory and the Extended Real Associated Solution(ERAS)model were employed to correlate the excess molar volume,while the Perturbed Chain Statistical Associating Fluid Theory(PC-SAFT)was used to predict the density of mixtures.
基金supported by the National Natural Science Foundation of China(U1507111).
文摘The phase equilibria relationship of the system RbCl-PEG6000-H2O were investigated at temperatures of 288.2,298.2,and 308.2 K,the compositions of solid-liquid equilibria(SLE)and liquid-liquid equilibria(LLE)were determined.The complete phase diagrams,binodal curve diagrams,and tie-line diagrams were all plotted.Results show that both solid-liquid equilibria and liquid-liquid equilibria relationships at each studied temperature.The complete phase diagrams at 288.2 K,298.2 K and 308.2 K consist of six phase regions:unsaturated liquid region(L),two saturated solutions with one solid phase of RbCl(L_S),one saturated liquid phase with two solid phases of PEG6000 and RbCl(2S+L),an aqueous two-phase region(2L),and a region with two liquids and one solid phase of RbCl(2L_S).With the increase in temperature,the layering ability of the aqueous two-phase system increases,and both regions(2L)and(2L_S)increase.The binodal curves were fitted using the nonlinear equations proposed by Mistry,Hu,and Jayapal.Additionally,the tie-line data were correlated with the Othmer-Tobias,Bancroft,Hand,and Bachman equations.The liquid-liquid equilibria at 288.2 K,298.2 K and 308.2 K were calculated using the NRTL model.The findings confirm that the experimental and calculated values are in close agreement,demonstrating the model’s effectiveness in representing the system’s behavior.
基金the expense of a grant of the Russian Science Foundation(project No.23-69-10006),https://rscf.ru/project/23-69-10006/(accessed on 6 May 2025).
文摘The article considers a relaxation of the water/polypropylene glycol-425 solution with a lower critical solution temperature(LCST)following its pulsed superheating concerning liquid-liquid and liquid-vapor equilibrium lines,as well as the liquid-liquid spinodal.Superheating was performed using the pulsed heat generation method in a micro-sized wire probe.The main heating mode was the constant(over the pulse length)power mode.Characteristic heating rates ranged from 0.05×10^(5) to 2×10^(5) K/s,while the degree of superheating concerning the spinodal was up to 200 K.The temperature of spontaneous boiling-up and the amplitude of the corresponding signal were monitored as functions of the heating rate set by the power value.The results demonstrate an example of the interaction of liquidliquid and liquid-vapor phase transitions,as well as the spinodal decomposition of a solution with LCST against the background of its unstable states.We proposed a physical model to explain the minimum spontaneous boiling-up temperature revealed within a certain range of heating rates,which is not typical of completely miscible solutions.Further research will focus on establishing a general criterion for the possibility of spinodal decomposition of such solutions under the conditions of rapid heating.
基金funded by the Research program FMUW-2021-0002 of the IPGG RAS.
文摘An equation of state(EOS)was obtained that accurately describes the thermodynamics of the system H_(2)O–CO_(2) at temperatures of 50–350°C and pressures of 0.2–3.5 kbar.The equation is based on experimental data on the compositions of the coexisting liquid and gas phases and the Van Laar model,within which the values of the Van Laar parameters A12 and A21 were found for each experimental P-T point.For the resulting sets A12(P,T),A21(P,T),approximation formulas describing the dependences of these quantities on temperature and pressure were found and the parameters contained in the formulas were fitted.This two-stage approach made it possible to obtain an adequate thermodynamic description of the system,which allows,in addition to determining the phase state of the system(homogeneous or heterogeneous),to calculate the excess free energy of mixing of H_(2)O and CO_(2),the activities of H_(2)O and CO_(2),and other thermodynamic characteristics of the system.The possibility of such calculations creates the basis for using the obtained EOS in thermodynamic models of more complicated fluid systems in P-T conditions of the middle and upper crust.These fluids play an important role in many geological processes including the transport of ore matter and forming hydrothermal ore deposits,in particular,the most of the world’s gold deposits.The knowledge of thermodynamics of these fluids is important in the technology of drilling oil and gas wells.In particular,this concerns the prevention of precipitation of solid salts in the well.
基金This work was supported by the National Natural Science Foundation of China(52204331)Natural Science Foundation of Anhui Province Youth Project(2208085QE145)the Open Project Program of Key Laboratory of Metallurgical Emission Reduction&Resources Recycling(Anhui University of Technology),Ministry of Education(JKF20–03).
文摘SiO_(2)is the main component of gangue in sinters and a crucial constituent in the formation of the SiO_(2)–Fe_(2)O_(3)–Cao(SFC)system.The non-isothermal crystallization kinetics of the SFC system were investigated using differential scanning calorimetry.The crystallization process of SFC was studied under different cooling rates(5,10,15,and 20 K/min),and the crystalline phases and microstructures of the SFC crystals were verified through X-ray diffraction and scanning electron microscopy.The results indicate that when the SiO_(2)content is 2 wt.%,increasing the cooling rate promotes the precipitation of CaFe_(2)O_(4)(CF)in the SFC system,thereby inhibiting the precipitation of Ca_(2)Fe_(2)O_(5)(C_(2)F).In contrast to the Cao–Fe_(2)O_(3)(C–F)system,the addition of SiO_(2)does not alter the precipitation mechanisms of C_(2)F and CF.By further adding SiO_(2),the precipitation of Ca_(2)Sio_(4)(C_(2)S)significantly increases.Simultaneously,the Cao content in the liquid phase decreases.This leads to the crystallization process of the CF_(4)S(4 wt.%Sio_(2))system bypassing the precipitation of C_(2)F and directly forming CF and CaFe_(4)O_(7)(CF_(2)).In the case of the CF_(8)S(8 wt.%SiO_(2))system,the crystallization process skips the precipitation of C_(2)F and CF,directly yielding CF_(2).The crystallization process of both CF_(2)S(2 wt.%Sio_(2))and CF is similar,comprising two reaction stages.The Ozawa method was used to calculate the activation energy for the crystallization of C_(2)F and CF as-329 and-419 kJ/mol,respectively.Analysis using the Malek method reveals model functions for both stages.
基金supported by the National Key Research and Development Program of China(2021YFC2103800)the National Natural Science Foundation of China(U21A20301)the Research Funds of Institute of Zhejiang University-Quzhou(IZQ2022RCZX004 and IZQ2021RCZX015)。
文摘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 pressure.The 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 system.To 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)model.The 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 data.The findings underscore that the dissolution process is predominantly endothermic across the solvent systems examined.Notably,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.
