To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life（EoL） superalloys, knowledge of their activity coefficien...To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life（EoL） superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO-Al_2O_3-SiO_2 slag. The activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag both show a positive deviation from Raoult＇s law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B =（%CaO）/（%SiO_2） = 1, where B is the basicity. We observed that controlling the slag composition at approximately B = 1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.展开更多
Geometrical optimization and electrostatic potential calculations have been performed for a series of halogenated hydrocarbons at the HF/Gen-6d level. A number of electrostatic potentials and the statistically based s...Geometrical optimization and electrostatic potential calculations have been performed for a series of halogenated hydrocarbons at the HF/Gen-6d level. A number of electrostatic potentials and the statistically based structural descriptors derived from these electrostatic potentials have been obtained. Multiple linear regression analysis and artificial neural network are employed simultaneously in this paper. The result shows that the parameters derived from electrostatic 2 potentials σtot^2, V s and ∑ Vs^＋, together with the molecular volume （Vine） can be used to express the quantitative structure-infinite dilution activity coefficients （γ^∞） relationship of halogenated hydrocarbons in water. The result also demonstrates that the model obtained by using BFGS quasiNewton neural network method has much better predictive capability than that from multiple linear regression. The goodness of the model has been validated through exploring the predictive power for the external test set. The model obtained via neural network may be applied to predict γ^∞ of other halogenated hydrocarbons not present in the data set.展开更多
It is important to know how ILs(ionic liquids)influence organic reaction.In this paper,activity coefficients at infinite dilution of more than 80 organic compounds in ILs are collected and analyzed systematically.Thro...It is important to know how ILs(ionic liquids)influence organic reaction.In this paper,activity coefficients at infinite dilution of more than 80 organic compounds in ILs are collected and analyzed systematically.Through the study on typical organic reactions happened in ILs,such as Diels-Alder,esterification and Friedel-Crafts reaction,the ratio of activity coefficients at infinite dilution of products and reactants is employed to estimate different effects of different structural ILs on the rate and selectivity of reactions.展开更多
The Clegg Pitzer semi empirical thermodynamic equations were applied to the calculation of 1 1 type potassium salt aqueous solution.At 25 ℃ and over the whole concentration range,from 8 single electrolyte solut...The Clegg Pitzer semi empirical thermodynamic equations were applied to the calculation of 1 1 type potassium salt aqueous solution.At 25 ℃ and over the whole concentration range,from 8 single electrolyte solutions (KF,KCl,KBr,KI,KOH,KNO 3,KClO 3,KBrO 3),the parameters W H 2O,KX ,U H 2O,KX ,and B KX were calculated,and then 8 solubility products were calculated.From 9 bi salt saturated aqueous solutions,the parameters W KXY ,U XY ,and Q H 2O,KXY were regressed,the F test was passed.展开更多
In this paper, we calculated 37 structural descriptors of 174 organic compounds. The 154 molecules were used to derive quantitative structure - infinite dilution activity confficient relationship by genetic programmin...In this paper, we calculated 37 structural descriptors of 174 organic compounds. The 154 molecules were used to derive quantitative structure - infinite dilution activity confficient relationship by genetic programming, the other 20 compounds were used to test the model. The result showed that molecular partition property and three-dimensional structural descriptors have significant influence on the infinite dilution activity coefficients.展开更多
Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G＊ level for 73 alcohol and ether organic compounds.Linear ...Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G＊ level for 73 alcohol and ether organic compounds.Linear relationships between infinite dilution activity coef-ficient（lnγ∞） of alcohols and ethers in water and theoretical descriptors of the molecular structure were established by multiple regression method.The result shows that the parameters derived from molecular electrostatic potential together with molecular surface area can be preferably used to express the quantitative structure-lnγ∞ relationship of alcohols and ethers in water.This reveals that this model has good predictive capabilities（RCV=0.969）.The molecular electrostatic potential has also been proved to have the general applicability in QSPR model of alcohol and ether organic compounds about γ∞ in water.The QSPR model established may provide a new powerful method for predicting γ∞ of organic compounds in aqueous systems.展开更多
The simple equation relating the activity coefficient of each solute in mixed electrolyte solution to its value in binary solutions under isopiestic equilibrium was tested by comparison with the experimental data for ...The simple equation relating the activity coefficient of each solute in mixed electrolyte solution to its value in binary solutions under isopiestic equilibrium was tested by comparison with the experimental data for the 18 electrolyte solutions consisting of 1：1, 1：2, and 1：3 electrolytes. The isopiestic measurements were made on the quaternary system BaCl2-NH4Br-NaI-H2O and its ternary subsystems NaI-NH4Br-H2O, NaI-BaCl2-H2O, and NH4Br-BaCl2-H2O at 298.15K. The results were used to test the applicability of the Zdanovskii＇s rule to the mixed electrolyte solutions which contain no common ions, and the agreement is excellent. The activity coefficients of the solutes in the above quaternary and ternary systems calculated from the above-mentioned simple equation are in good agreement with the Pitzer＇s equation.展开更多
Raoultian activity coefficients γ0c of C in infinitely dilute Fe-C binary melts at temperatures of 1833, 1873, 1923, and 1973 K have been determined from the converted mass action concentrations Nc of C in Fe-C binar...Raoultian activity coefficients γ0c of C in infinitely dilute Fe-C binary melts at temperatures of 1833, 1873, 1923, and 1973 K have been determined from the converted mass action concentrations Nc of C in Fe-C binary melts by the developed AMCT-Ni model based on the atom-molecule coexistence theory （AMCT）. The obtained expression of γ0c by the developed AMCT-Ni model has been evaluated to be accurate based on the reported ones from the literature. Meanwhile, three activity coefficients γc,f%,c, andfH,c of C coupled with activity aR,C or a%,c or aH,c have been obtained by the developed AMCT-Ni model and assessed through comparing with the predicted ones by other models from the literature. The first-order activity interaction coefficients ec, ec, and hcc related to γc f%,c, and fH,c are also determined and assessed in comparison with the reported ones from the literature. Furthermore, the integral molar mixing thermodynamic functions such as AmixHm,Fe-C, △mix-Sm,Fe-C, and △mixGm,Fe-C of Fe-C binary melts over a temperature range from 1833 to 1973 K have been determined and evaluated to be valid based on the determined ones from the literature.展开更多
This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice（QRL） model. The osmotic coefficients were then calculated c...This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice（QRL） model. The osmotic coefficients were then calculated consistently, through the integration of the Gibbs-Duhem equation. Using of QRL was mainly motivated by its dependence on one parameter, given in the form of an electrolyte-dependent concentration, which was also the highest concentration at which the model could be applied. For all the electrolyte solutions here considered, this parameter was experimentally known and ranged from 1.5 to 2.2 mol/kg, at 25 ℃.Accordingly, rare- earth halide concentrations from strong dilution up to 2 mol/kg about could be considered without need for best-fit treatment in order to compute their osmotic and mean activity coefficients. The experimental knowledge about the parameter was an advantageous feature of QRL compared to existing literature models. Following a trend already observed with low charge electrolytes,a satisfactory agreement was obtained with the experimental values for all the investigated rare-earth chlorides and bromides. For the sake of compactness, in this work the considered rare-earth halides were all belonging to the P63/m space group in their crystalline（anhydrous） form.展开更多
A quantitative structure-property relationship （QSPR） study was suggested for the prediction of infinite dilution activity coefficients of halogenated hydrocarbons, γ∞ , in water at 298.15 K. After optimization of...A quantitative structure-property relationship （QSPR） study was suggested for the prediction of infinite dilution activity coefficients of halogenated hydrocarbons, γ∞ , in water at 298.15 K. After optimization of 3D geometry of the halogenated hydrocarbons with semi-empirical quantum chemical calculations at the AM1 level, different descriptors （1514 descriptors） were calculated by the HyperChem and Dragon softwares. A major problem of QSPR is the high dimensionality of the descriptor space; therefore, descriptor selection is the most important step. In this paper, an ant colony optimization （ACO） algorithm was proposed to select the best descriptors. Then the selected descriptors were applied for model development using multiple linear regression. The average absolute relative deviation and correlation coefficient for the training set were obtained as 4.36% and 0.951, respectively, while the corresponding values for the test set were 5.96% and 0.929, respectively. The results showed that the applied procedure is suitable for the prediction of γ∞ of halogenated hydrocarbons in water.展开更多
The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficientsγ∞at infinite dilution of a...The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficientsγ∞at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement ofγ∞by gas-liquid chromatography is a speedy and cost-saving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylben-zenes,styrene,in 1-allyl-3-methylimidazolium tetrafluorobo-rate([AMIM][BF4])and 1-butyl-3-methyl imidazolium hexafluorophosphate([BMIM][PF6]),1-isobutenyl-3-methylimidazolium tetrafluoroborate([MPMIM][BF4])and[MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure para-meters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.展开更多
The mean activity coefficients of NaCl in ethylene glycol-water mixtures were determined in the range of w = 0.10 to 0.40 ethylene glycol at 288.15, 298.15 and 308.15 K using potentiometric measurements. The Pitzer an...The mean activity coefficients of NaCl in ethylene glycol-water mixtures were determined in the range of w = 0.10 to 0.40 ethylene glycol at 288.15, 298.15 and 308.15 K using potentiometric measurements. The Pitzer and extended Debye-Htickel equations were used to describe the nonideal behavior of the electrolyte. Osmotic coefficients and the standard Gibbs energy of NaCl-ethylene glycol-water were calculated.展开更多
Activitibs of Si in binary Cu-Si and ternary Cu-Ti-Si melts were measured at 1 550℃ by using a method of chemical equilIbrium between gas and liquid. The activity interaction coefficients of Si in the melts have been...Activitibs of Si in binary Cu-Si and ternary Cu-Ti-Si melts were measured at 1 550℃ by using a method of chemical equilIbrium between gas and liquid. The activity interaction coefficients of Si in the melts have been determined from the experimental data (lny = -5.69. s = 6.69. P2: = -26.22. E; =-43.96) and activity interaction coefficients of Ti in binary Cu-Ti melt at 1550℃ has been estimated from Sommer's data based on the regular solution model (lny =-1 .10. : = 2.95.p:=-2.10).展开更多
The relation between contents of cerium and impurity lead or bismuth to their activity coefficient in Ag, Cu and Zn-base alloy was calculated and analyzed by using the ternary system Chou model. The thermodynamic calc...The relation between contents of cerium and impurity lead or bismuth to their activity coefficient in Ag, Cu and Zn-base alloy was calculated and analyzed by using the ternary system Chou model. The thermodynamic calculation results show that the 'equivalent activity coefficient phenomenon' emerges among the activity coefficient of solute in a certain range of cerium (or at a certain point) for the Ce-Pb-X and Ce-Bi-X (X=Ag, Cu or Zn) ternary alloy system. Under this condition, the activity coefficient of solute has nothing to do with its own concentration. The preliminary theoretical analysis to this phenomenon was also made.展开更多
The infinite diluted activity coefficients of solvents in polyisopropyl methylacrylate was measured using inverse gas chromatography. The solvents used were benzene, toluene, ethyl benzene, methyl acetate, ethyl aceta...The infinite diluted activity coefficients of solvents in polyisopropyl methylacrylate was measured using inverse gas chromatography. The solvents used were benzene, toluene, ethyl benzene, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methanol, ethanol isopropyl alcohol, butyl alcohol, 1,2-dichloroethane, and chloroform. It was observed that the infinite diluted activity coefficient of alcohols are well above those of the other solvents investigated.展开更多
The density functional theory （DFT） and density functional perturbation theory （DFPT） within the quasi-harmonic ap-proximation were employed to investigate the activity coefficient of Y in dilute Fe-Y solid soluti...The density functional theory （DFT） and density functional perturbation theory （DFPT） within the quasi-harmonic ap-proximation were employed to investigate the activity coefficient of Y in dilute Fe-Y solid solution. The ground states of Fe-Y com-pounds and the thermodynamic properties of bcc Fe were calculated, and the stable and metastable structures of Fe-Y compounds were predicted as well. With the temperature increasing, the Y activity coefficient in bcc Fe matrix increased rapidly, and the interac-tion between Y and Fe became more favorable. Based on the calculated thermodynamic properties, the solubility of Y in bcc Fe ma-trix as a function of temperature was predicted, and compared with the experimental data.展开更多
The modified sub regular solution model was used for a calculation of the activity coefficient of immiscible binary alloy systems. The parameters needed for the calculation are the interaction parameters, λ 1 a...The modified sub regular solution model was used for a calculation of the activity coefficient of immiscible binary alloy systems. The parameters needed for the calculation are the interaction parameters, λ 1 and λ 2, which are represented as a linear function of temperature, T . The molar excess Gibbs free energy, G m E, can be written in the form G m E= x A x B[( λ 11 + λ 12 T )+( λ 21 + λ 22 T ) x B ] The calculation is carried out numerically for three immiscible binary alloy systems, Al Pb, Cu Tl and In V. The agreement between the calculated and experimentally determined values of activity coefficient is excellent.展开更多
In this paper,the polymer chain of rotator(PCOR) equation of state(EOS) was used together with an EOS/G^E mixing rule(MHV1) and the Wilson's equation as an excess-Gibbs-energy model in the proposed approach to ext...In this paper,the polymer chain of rotator(PCOR) equation of state(EOS) was used together with an EOS/G^E mixing rule(MHV1) and the Wilson's equation as an excess-Gibbs-energy model in the proposed approach to extend the capability and improve the accuracy of the PCOR EOS for predicting the Henry's constant of solutions containing polymers.The results of the proposed method compared with two equation of state(van der Waals and GC-Flory) and three activity coefficient models(UNIFAC,UNIFAC-FV and Entropic-FV) indicated that the PCOR EOS/Wilson's equation provided more accurate results.The interaction parameters of Wilson's equation were fitted with Henry's constant experimental data and the property parameters of PCOR,a and b,were fitted with experimental volume data(Tait equation).As a result,the present work provided a simple and useful model for prediction of Henry's constant for polymer solutions.展开更多
Activities and activity coefficients of Al in solid Cu-AI alloys have been determined by means of solid electorlyte galvanic cells Al(a_1 , in alloy), Al_2O_3 | ZrO_2· Y_2O_3 | Ni, NiO and Al(a_1 , in alloy), A...Activities and activity coefficients of Al in solid Cu-AI alloys have been determined by means of solid electorlyte galvanic cells Al(a_1 , in alloy), Al_2O_3 | ZrO_2· Y_2O_3 | Ni, NiO and Al(a_1 , in alloy), Al_2O_3 | Na, βAl_2O_3 | Al(a_2 , in alloy), Al_2O_3展开更多
Carbon solubility in Fe-Mn melts （XFe =0. 102 3-0. 789 9, XMn =0. 055 1-0. 638 0） was measured experimentally at various temperatures. Using Gibbs-Duhem equation, in combination with the experimental results in this...Carbon solubility in Fe-Mn melts （XFe =0. 102 3-0. 789 9, XMn =0. 055 1-0. 638 0） was measured experimentally at various temperatures. Using Gibbs-Duhem equation, in combination with the experimental results in this work, quoting experimental data reported in references, and by strict thermodynamic derivation and calculation, the relation equations between the activity interaction parameters in Fe-C system and temperature were obtained. The calculation equation of lnyFe. in Fe-C system was also obtained. The calculated results show that these relation equations can be used to calculate the activity coefficients of carbon and iron in Fe-C system and can satisfy the necessary condition to satisfy Gibbs-Duhem equation and the necessary condition to satisfy the stability condition of system at high carbon content. The calculation formula for lnTc in Fe-Mn-C system was also obtained.展开更多
基金the support of a scholarship provided by the Japan Society for the Promotion of Science(No. H26-3293)the scholarship provided by the Ministry of Education,Culture,Sports,Science and Technology,Japan(Registered number: 123032) during his doctor course
文摘To design optimal pyrometallurgical processes for nickel and cobalt recycling, and more particularly for the end-of-life process of Ni-Co-Fe-based end-of-life（EoL） superalloys, knowledge of their activity coefficients in slags is essential. In this study, the activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag, a candidate slag used for the EoL superalloy remelting process, were measured using gas/slag/metal equilibrium experiments. These activity coefficients were then used to consider the recycling efficiency of nickel and cobalt by remelting EoL superalloys using CaO-Al_2O_3-SiO_2 slag. The activity coefficients of NiO and CoO in CaO-Al_2O_3-SiO_2 slag both show a positive deviation from Raoult＇s law, with values that vary from 1 to 5 depending on the change in basicity. The activity coefficients of NiO and CoO peak in the slag with a composition near B =（%CaO）/（%SiO_2） = 1, where B is the basicity. We observed that controlling the slag composition at approximately B = 1 effectively reduces the cobalt and nickel oxidation losses and promotes the oxidation removal of iron during the remelting process of EoL superalloys.
文摘Geometrical optimization and electrostatic potential calculations have been performed for a series of halogenated hydrocarbons at the HF/Gen-6d level. A number of electrostatic potentials and the statistically based structural descriptors derived from these electrostatic potentials have been obtained. Multiple linear regression analysis and artificial neural network are employed simultaneously in this paper. The result shows that the parameters derived from electrostatic 2 potentials σtot^2, V s and ∑ Vs^＋, together with the molecular volume （Vine） can be used to express the quantitative structure-infinite dilution activity coefficients （γ^∞） relationship of halogenated hydrocarbons in water. The result also demonstrates that the model obtained by using BFGS quasiNewton neural network method has much better predictive capability than that from multiple linear regression. The goodness of the model has been validated through exploring the predictive power for the external test set. The model obtained via neural network may be applied to predict γ^∞ of other halogenated hydrocarbons not present in the data set.
基金Supported by the National Natural Science Foundation of China（21176248）
文摘It is important to know how ILs(ionic liquids)influence organic reaction.In this paper,activity coefficients at infinite dilution of more than 80 organic compounds in ILs are collected and analyzed systematically.Through the study on typical organic reactions happened in ILs,such as Diels-Alder,esterification and Friedel-Crafts reaction,the ratio of activity coefficients at infinite dilution of products and reactants is employed to estimate different effects of different structural ILs on the rate and selectivity of reactions.
文摘The Clegg Pitzer semi empirical thermodynamic equations were applied to the calculation of 1 1 type potassium salt aqueous solution.At 25 ℃ and over the whole concentration range,from 8 single electrolyte solutions (KF,KCl,KBr,KI,KOH,KNO 3,KClO 3,KBrO 3),the parameters W H 2O,KX ,U H 2O,KX ,and B KX were calculated,and then 8 solubility products were calculated.From 9 bi salt saturated aqueous solutions,the parameters W KXY ,U XY ,and Q H 2O,KXY were regressed,the F test was passed.
文摘In this paper, we calculated 37 structural descriptors of 174 organic compounds. The 154 molecules were used to derive quantitative structure - infinite dilution activity confficient relationship by genetic programming, the other 20 compounds were used to test the model. The result showed that molecular partition property and three-dimensional structural descriptors have significant influence on the infinite dilution activity coefficients.
文摘Based on QSPR of alcohol and ether organic compounds in water,geometrical optimization and electrostatic potential calculations were performed at the HF/6-31G＊ level for 73 alcohol and ether organic compounds.Linear relationships between infinite dilution activity coef-ficient（lnγ∞） of alcohols and ethers in water and theoretical descriptors of the molecular structure were established by multiple regression method.The result shows that the parameters derived from molecular electrostatic potential together with molecular surface area can be preferably used to express the quantitative structure-lnγ∞ relationship of alcohols and ethers in water.This reveals that this model has good predictive capabilities（RCV=0.969）.The molecular electrostatic potential has also been proved to have the general applicability in QSPR model of alcohol and ether organic compounds about γ∞ in water.The QSPR model established may provide a new powerful method for predicting γ∞ of organic compounds in aqueous systems.
基金the National-Natural Science Foundation of China （No.20476059, No.20276037） and 863 Hi-Technology Research and Development Program of China （2004 AA616040）.
文摘The simple equation relating the activity coefficient of each solute in mixed electrolyte solution to its value in binary solutions under isopiestic equilibrium was tested by comparison with the experimental data for the 18 electrolyte solutions consisting of 1：1, 1：2, and 1：3 electrolytes. The isopiestic measurements were made on the quaternary system BaCl2-NH4Br-NaI-H2O and its ternary subsystems NaI-NH4Br-H2O, NaI-BaCl2-H2O, and NH4Br-BaCl2-H2O at 298.15K. The results were used to test the applicability of the Zdanovskii＇s rule to the mixed electrolyte solutions which contain no common ions, and the agreement is excellent. The activity coefficients of the solutes in the above quaternary and ternary systems calculated from the above-mentioned simple equation are in good agreement with the Pitzer＇s equation.
文摘Raoultian activity coefficients γ0c of C in infinitely dilute Fe-C binary melts at temperatures of 1833, 1873, 1923, and 1973 K have been determined from the converted mass action concentrations Nc of C in Fe-C binary melts by the developed AMCT-Ni model based on the atom-molecule coexistence theory （AMCT）. The obtained expression of γ0c by the developed AMCT-Ni model has been evaluated to be accurate based on the reported ones from the literature. Meanwhile, three activity coefficients γc,f%,c, andfH,c of C coupled with activity aR,C or a%,c or aH,c have been obtained by the developed AMCT-Ni model and assessed through comparing with the predicted ones by other models from the literature. The first-order activity interaction coefficients ec, ec, and hcc related to γc f%,c, and fH,c are also determined and assessed in comparison with the reported ones from the literature. Furthermore, the integral molar mixing thermodynamic functions such as AmixHm,Fe-C, △mix-Sm,Fe-C, and △mixGm,Fe-C of Fe-C binary melts over a temperature range from 1833 to 1973 K have been determined and evaluated to be valid based on the determined ones from the literature.
文摘This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice（QRL） model. The osmotic coefficients were then calculated consistently, through the integration of the Gibbs-Duhem equation. Using of QRL was mainly motivated by its dependence on one parameter, given in the form of an electrolyte-dependent concentration, which was also the highest concentration at which the model could be applied. For all the electrolyte solutions here considered, this parameter was experimentally known and ranged from 1.5 to 2.2 mol/kg, at 25 ℃.Accordingly, rare- earth halide concentrations from strong dilution up to 2 mol/kg about could be considered without need for best-fit treatment in order to compute their osmotic and mean activity coefficients. The experimental knowledge about the parameter was an advantageous feature of QRL compared to existing literature models. Following a trend already observed with low charge electrolytes,a satisfactory agreement was obtained with the experimental values for all the investigated rare-earth chlorides and bromides. For the sake of compactness, in this work the considered rare-earth halides were all belonging to the P63/m space group in their crystalline（anhydrous） form.
文摘A quantitative structure-property relationship （QSPR） study was suggested for the prediction of infinite dilution activity coefficients of halogenated hydrocarbons, γ∞ , in water at 298.15 K. After optimization of 3D geometry of the halogenated hydrocarbons with semi-empirical quantum chemical calculations at the AM1 level, different descriptors （1514 descriptors） were calculated by the HyperChem and Dragon softwares. A major problem of QSPR is the high dimensionality of the descriptor space; therefore, descriptor selection is the most important step. In this paper, an ant colony optimization （ACO） algorithm was proposed to select the best descriptors. Then the selected descriptors were applied for model development using multiple linear regression. The average absolute relative deviation and correlation coefficient for the training set were obtained as 4.36% and 0.951, respectively, while the corresponding values for the test set were 5.96% and 0.929, respectively. The results showed that the applied procedure is suitable for the prediction of γ∞ of halogenated hydrocarbons in water.
基金supported by the Science Foundation of China Petroleum&Chemical Corporation(Grant No.X504031).
文摘The separations of olefin/paraffin,aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers.Activity coefficientsγ∞at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation.In fact,the measurement ofγ∞by gas-liquid chromatography is a speedy and cost-saving method.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylben-zenes,styrene,in 1-allyl-3-methylimidazolium tetrafluorobo-rate([AMIM][BF4])and 1-butyl-3-methyl imidazolium hexafluorophosphate([BMIM][PF6]),1-isobutenyl-3-methylimidazolium tetrafluoroborate([MPMIM][BF4])and[MPMIM][BF4]-AgBF4 have been determined by gas-liquid chromatography using ionic liquids as stationary phase.The measurements were carried out at different temperatures from 298 to 318 K.The separating effects of these ionic liquids for alkanes/hexane,aliphatic hydrocarbons/benzene and hexene isomers have been discussed.The hydrophobic parameter,dipole element,frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method.The quantitative relations among the computed structure para-meters and activity coefficients at infinite dilution were also developed.The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.
基金Project supported by the National Natural Science Foundation of China （No. 20871079） and the Fundamental Research Funds for the Central Uni- versities （No. 2010ZYGX027）.
文摘The mean activity coefficients of NaCl in ethylene glycol-water mixtures were determined in the range of w = 0.10 to 0.40 ethylene glycol at 288.15, 298.15 and 308.15 K using potentiometric measurements. The Pitzer and extended Debye-Htickel equations were used to describe the nonideal behavior of the electrolyte. Osmotic coefficients and the standard Gibbs energy of NaCl-ethylene glycol-water were calculated.
文摘Activitibs of Si in binary Cu-Si and ternary Cu-Ti-Si melts were measured at 1 550℃ by using a method of chemical equilIbrium between gas and liquid. The activity interaction coefficients of Si in the melts have been determined from the experimental data (lny = -5.69. s = 6.69. P2: = -26.22. E; =-43.96) and activity interaction coefficients of Ti in binary Cu-Ti melt at 1550℃ has been estimated from Sommer's data based on the regular solution model (lny =-1 .10. : = 2.95.p:=-2.10).
文摘The relation between contents of cerium and impurity lead or bismuth to their activity coefficient in Ag, Cu and Zn-base alloy was calculated and analyzed by using the ternary system Chou model. The thermodynamic calculation results show that the 'equivalent activity coefficient phenomenon' emerges among the activity coefficient of solute in a certain range of cerium (or at a certain point) for the Ce-Pb-X and Ce-Bi-X (X=Ag, Cu or Zn) ternary alloy system. Under this condition, the activity coefficient of solute has nothing to do with its own concentration. The preliminary theoretical analysis to this phenomenon was also made.
基金Supported by the National Natural Science Foundation of China(No.29736170,No.29976011)
文摘The infinite diluted activity coefficients of solvents in polyisopropyl methylacrylate was measured using inverse gas chromatography. The solvents used were benzene, toluene, ethyl benzene, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methanol, ethanol isopropyl alcohol, butyl alcohol, 1,2-dichloroethane, and chloroform. It was observed that the infinite diluted activity coefficient of alcohols are well above those of the other solvents investigated.
基金supported by the National Natural Science Foundation of China(51101083)
文摘The density functional theory （DFT） and density functional perturbation theory （DFPT） within the quasi-harmonic ap-proximation were employed to investigate the activity coefficient of Y in dilute Fe-Y solid solution. The ground states of Fe-Y com-pounds and the thermodynamic properties of bcc Fe were calculated, and the stable and metastable structures of Fe-Y compounds were predicted as well. With the temperature increasing, the Y activity coefficient in bcc Fe matrix increased rapidly, and the interac-tion between Y and Fe became more favorable. Based on the calculated thermodynamic properties, the solubility of Y in bcc Fe ma-trix as a function of temperature was predicted, and compared with the experimental data.
文摘The modified sub regular solution model was used for a calculation of the activity coefficient of immiscible binary alloy systems. The parameters needed for the calculation are the interaction parameters, λ 1 and λ 2, which are represented as a linear function of temperature, T . The molar excess Gibbs free energy, G m E, can be written in the form G m E= x A x B[( λ 11 + λ 12 T )+( λ 21 + λ 22 T ) x B ] The calculation is carried out numerically for three immiscible binary alloy systems, Al Pb, Cu Tl and In V. The agreement between the calculated and experimentally determined values of activity coefficient is excellent.
基金financial support provided by Islamic Azad University of Mahshahr Branch,Iran
文摘In this paper,the polymer chain of rotator(PCOR) equation of state(EOS) was used together with an EOS/G^E mixing rule(MHV1) and the Wilson's equation as an excess-Gibbs-energy model in the proposed approach to extend the capability and improve the accuracy of the PCOR EOS for predicting the Henry's constant of solutions containing polymers.The results of the proposed method compared with two equation of state(van der Waals and GC-Flory) and three activity coefficient models(UNIFAC,UNIFAC-FV and Entropic-FV) indicated that the PCOR EOS/Wilson's equation provided more accurate results.The interaction parameters of Wilson's equation were fitted with Henry's constant experimental data and the property parameters of PCOR,a and b,were fitted with experimental volume data(Tait equation).As a result,the present work provided a simple and useful model for prediction of Henry's constant for polymer solutions.
文摘Activities and activity coefficients of Al in solid Cu-AI alloys have been determined by means of solid electorlyte galvanic cells Al(a_1 , in alloy), Al_2O_3 | ZrO_2· Y_2O_3 | Ni, NiO and Al(a_1 , in alloy), Al_2O_3 | Na, βAl_2O_3 | Al(a_2 , in alloy), Al_2O_3
基金Item Sponsored by National Natural Science Foundation of China (50374002)
文摘Carbon solubility in Fe-Mn melts （XFe =0. 102 3-0. 789 9, XMn =0. 055 1-0. 638 0） was measured experimentally at various temperatures. Using Gibbs-Duhem equation, in combination with the experimental results in this work, quoting experimental data reported in references, and by strict thermodynamic derivation and calculation, the relation equations between the activity interaction parameters in Fe-C system and temperature were obtained. The calculation equation of lnyFe. in Fe-C system was also obtained. The calculated results show that these relation equations can be used to calculate the activity coefficients of carbon and iron in Fe-C system and can satisfy the necessary condition to satisfy Gibbs-Duhem equation and the necessary condition to satisfy the stability condition of system at high carbon content. The calculation formula for lnTc in Fe-Mn-C system was also obtained.
