Struvite(MAP)crystallization technology is widely used to treat ammonia nitrogen in waste effluents of its simple operation and good removal efficiency.However,the presence of heavy metal ions in the waste effluents c...Struvite(MAP)crystallization technology is widely used to treat ammonia nitrogen in waste effluents of its simple operation and good removal efficiency.However,the presence of heavy metal ions in the waste effluents causes problems such as slow crystallization rate and small crystal size,limiting the recovery rate and economic value of the MAP.The present study was conducted to investigate the effects of concentrations of three heavy metal ions(Cu^(2+),Zn^(2+),and Pb^(2+))on the crystal morphology,crystal size,average growth rate,and crystallization kinetics of MAP.A relationship was established between the kinetic rate constant Ktcalculated by the chemical gradient model and the concentrations of heavy metal ions.The results showed that low concentrations of heavy metal ions in the solution created pits on the MAP surface,and high level of heavy metal ions generated flocs on the MAP surface,which were composed of metal hydroxides,thus inhibiting crystal growth.The crystal size,average growth rate,MAP crystallization rate,and kinetic rate constant Ktdecreased with the increase in heavy metal ion concentration.Moreover,the Ktdemonstrated a linear relationship with the heavy metal concentration ln(C/C~*),which provided a reference for the optimization of the MAP crystallization process in the presence of heavy metal ions.展开更多
Absolute rate constants for the reaction of ozone with dimethyl sulfide (DMS) were measured in a 200-L Teflon chamber over the temperature range of 283-353 K. Measurements were carried out using DMS in large excess ...Absolute rate constants for the reaction of ozone with dimethyl sulfide (DMS) were measured in a 200-L Teflon chamber over the temperature range of 283-353 K. Measurements were carried out using DMS in large excess over ozone of 10 to 1 or greater. Over the indicated temperature range, the data could be fit to the simple Arrhenius expression as kDMS = (9.96 ± 3.61) × 10^-11 exp (-(7309.7 ± 1098.2)/T) cm^3/(molecule.s). A compared investigation of the reaction between ozone and ethene had a kC2H4 value of (1.35 ± 0.11) × 10^-18 cm^3/(molecule.s) at room temperature.展开更多
Structural and thermodynamic parameters of 16 chloro-phenol compounds in water solution were calculated and fully optimized by using Onsager model in self-consistent reaction field(SCRF) based on the B3LYP/6-311G*...Structural and thermodynamic parameters of 16 chloro-phenol compounds in water solution were calculated and fully optimized by using Onsager model in self-consistent reaction field(SCRF) based on the B3LYP/6-311G** level.These quantum chemical parameters were used as theoretical descriptors to correlate with the experimental biodegradation rate constant(Kb) of 16 compounds by stepwise multiple linear regression.As a result,a three-parameter model including molecular average polarizability(α),entropy(Sθ),and molar heat capacity at constant volume(CVθ) were established for Kb prediction,which was proposed with correlation coefficient R2 = 0.894.α exhibits the most significant effect on Kb.Variance analysis and standard t-value test were applied to validate the model.As expected,this model exhibits good robustness and prediction ability,which can be used in Kb prediction of analogs.展开更多
A simple model for estimating the rate constant between CO2-CO gas and molten slag containing iron oxides was developed using optical basicity only. In this model, the temperature dependence of the rate constant can b...A simple model for estimating the rate constant between CO2-CO gas and molten slag containing iron oxides was developed using optical basicity only. In this model, the temperature dependence of the rate constant can be described by the Arrhenius law, and the activation energy can be expressed with a linear function of the slag's optical basicity. The model was applied to some molten slag systems, such as FeO, FeO-CaO, FeO-SiO2, FeO-Na2O, FeO-CaO-SiO2, FeO-SiO2-P2O5, FeO-SiOE-Na2O, and FeO-CaO-SiOE-P2O5. A comparison between the predicted results and measured data showed that the model worked well.展开更多
Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydrox...Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.展开更多
A quasi-classical trajectory(QCT) calculation is used to investigate the vector and scalar properties of the D + Br O → DBr + O reaction based on an ab initio potential energy surface(X1A state) with collision ...A quasi-classical trajectory(QCT) calculation is used to investigate the vector and scalar properties of the D + Br O → DBr + O reaction based on an ab initio potential energy surface(X1A state) with collision energy ranging from 0.1 kcal/mol to 6 kcal/mol. The reaction probability, the cross section, and the rate constant are studied. The probability and the cross section show decreasing behaviors as the collision energy increases. The distribution of the rate constant indicates that the reaction favorably occurs in a relatively low-temperature region(T 〈 100 K). Meanwhile, three product angular distributions P(θr), P(φr), and P(θr, φr) are presented, which reflect the positive effect on the rotational angular momentum j' polarization of the DBr product molecule. In addition, two of the polarization-dependent generalized differential cross sections(PDDCSs), PDDCS00 and PDDCS20, are computed as well. Our results demonstrate that both vector and scalar properties have strong energy dependence.展开更多
Rate constants for the reactions of NO3 and SO4 radicals with oxalic acid and oxalate anions in aqueous solution have been measured using pulse radiolysis and laser flash photolysis.
A dynamic method is employed to study the reaction mechanisms of CH3CH2OCF3 with the hydrogen trioxy (HOOO) radical. In our paper, the geometries and harmonic vibrational frequencies of all the stationary points and...A dynamic method is employed to study the reaction mechanisms of CH3CH2OCF3 with the hydrogen trioxy (HOOO) radical. In our paper, the geometries and harmonic vibrational frequencies of all the stationary points and minimum energy paths (MEPs) are calculated at the MPW1K/6-31+G(d,p) level of theory, and the energetic information along MEPs is further refined by the CCSD/6-31+G(df, p) level of theory. The rate constants are evaluated with the conventional transition-state theory (TST), the canonical variational transition-state theory (CVT), the microcanonical variational transition-state theory (μVT), the CVT coupled with the small-curvature tunneling (SCT) correction (CVT/SCT), and the μVT coupled with the Eckart tunneling correction μVT/Eckart) based on the ab initio calculations in the temperature range of 200-3000 K. The theoretical results are important in determining the atmospheric lifetime and the feasible pathways for the loss of HFEs.展开更多
The application of Monte Carlo method in estimating rate constants for polymerization was described, A general program for Monte Carlo simulation was determined first according to the elementary reactions, after which...The application of Monte Carlo method in estimating rate constants for polymerization was described, A general program for Monte Carlo simulation was determined first according to the elementary reactions, after which the rate constants could be automatically adjusted and optimized through comparing of experimental and simulated data with an error expression that meeted a given minimum criterion. Such a process made the rate constants to be estimated without kinetic model in advance. The technique was applied to estimate the rate constants of the bulk polymerization of styrene catalyzed by the rare earth catalyst. The esthnated results showed the Monte Carlo method was feasible and effective for estimating rate constants in polymerization engineering.展开更多
A new approach was employed to calculate the canonical (thermal) rate constant basedon unified statistical theory. All information for the calculation was obtained from ab initio meth-ods. The flux integral for any po...A new approach was employed to calculate the canonical (thermal) rate constant basedon unified statistical theory. All information for the calculation was obtained from ab initio meth-ods. The flux integral for any point of reaction coordinate was calculated by counting the numberof quantum states and applied to determine the dividing surfaces along the intrinsic reaction coor-dinate (IRC). The classical exchange reaction H2+H, as an example, was investigated. The IRC forthe reaction has been traced and detailed information of IRC was carried out at the QCISD/6-311 G** level .The calculated rate constants are well consistent with the experimental results.展开更多
After the electron transfers from the metal electrode to the Fe3+(H2O)(6) ion, the free energy of activation of this electron transfer reaction is calculated, then using the transition probability which is calculated ...After the electron transfers from the metal electrode to the Fe3+(H2O)(6) ion, the free energy of activation of this electron transfer reaction is calculated, then using the transition probability which is calculated by the perturbed degeneration theory and the Fermi golden rule,, the rate constant is gotten. Compared with the experimental results, it is satisfactory.展开更多
The new theoretical models describe both the solubility S of the shot chain n-alkanes in water at 298.15 K, and their reaction rate constants k with nitronium cation NO<sub>2</sub><sup>+ </sup>...The new theoretical models describe both the solubility S of the shot chain n-alkanes in water at 298.15 K, and their reaction rate constants k with nitronium cation NO<sub>2</sub><sup>+ </sup>at 293.15 K on the basis of their molecular orbital characteristics. It is shown that both the quantities S and k are determined by the energies E<sub>orb</sub> of the specific virtual (for S) and occupied (for k) molecular orbitals of these n-alkanes. The obtained regression equations confirm the theoretically found dependences of S and k on the absolute value of E<sub>orb</sub>. This fact demonstrates that the electronic structure particularities of the studied n-alkanes play a crucial role in both their above-mentioned physicochemical properties.展开更多
The transition state(TS) and Intrinsic Reaction Coordinate (IRC) for the titled reaction were traced by means of MCSCF/6-31G (210 configurations). The reaction activation energy of this reaction is 140.2KJ/mol. The re...The transition state(TS) and Intrinsic Reaction Coordinate (IRC) for the titled reaction were traced by means of MCSCF/6-31G (210 configurations). The reaction activation energy of this reaction is 140.2KJ/mol. The reaction rate constants of five temperetures were calculated by CVT involving the tunneling effects.展开更多
A single-sweep oscillopolarographic procedure is descrital which allows detethenahon of rateconstants for reachons of oH. For a wide range of compounds, the results fit well with rate constantspreviously obtained with...A single-sweep oscillopolarographic procedure is descrital which allows detethenahon of rateconstants for reachons of oH. For a wide range of compounds, the results fit well with rate constantspreviously obtained with other methods. Rate constants for reactions of six kinds of active compoundscontalned in rheum, a tradihonal Chinese herb, have been deteboned by this method. Rcationmechanism ha5 also been discussed.展开更多
The kinetics and mechanisms of H abstraction reaction between isoflurane and a CI atom have been investigated using DFT and G3(MP2) methods of theory. The geometrical structures of all species were optimized by the ...The kinetics and mechanisms of H abstraction reaction between isoflurane and a CI atom have been investigated using DFT and G3(MP2) methods of theory. The geometrical structures of all species were optimized by the wB97XD/6-311++G** method. Intrinsic reaction coordinate (IRC) analysis has been carried out for the reaction channels. Thermochemistry data have been obtained by utilizing the high accurate model chemistry method G3(MP2) combined with the standard statistical thermodynamic calculations. Gibbs free energies were used for reaction channels analysis. Two channels were obtained, which correspond to P(1) and P(2). The rate constants for the two channels over a wide temperature range of 200-2000 K were also obtained. The results show that the barriers of P(1) and P(2) reaction channels are 50.36 and 50.34 kJ/mol, respectively, predicting that it exists two competitive channels. The calculated rate constant is in good agreement with the experiment value. Additionally, the results also show that the rate constants also increase from 1.85x10^-16 to 2.16x 10^12 cm3.moleculel.s-1 from 200 to 2000 K展开更多
A new method,which correlates rate constants of chemical reactions and density or pressure in supercritical fluids,was developed.Based on the transition state theory and thermodynamic principles, the rate constant can...A new method,which correlates rate constants of chemical reactions and density or pressure in supercritical fluids,was developed.Based on the transition state theory and thermodynamic principles, the rate constant can be reasonably correlated with the density of the supercritical fluid,and a correlation equation was obtained. Coupled with the equation of state (EOS) of a supercritical solvent,the effect of pressure on reaction rate constant could be represented.Two typical systems were used to test this method.The result indicates that this method is suitable for dilute supercritical fluid solutions.展开更多
The density of fine coal has a major effect on the value of its flotation rate constant. The collector dose can increase the flotation rate of fine coal, especially for low ash coal, but the effect for gangue is not n...The density of fine coal has a major effect on the value of its flotation rate constant. The collector dose can increase the flotation rate of fine coal, especially for low ash coal, but the effect for gangue is not notable. The flotation rate of gangue is mainly governed by the water entrainment. A coal flotation rate constant model has been developed.展开更多
Coal fly ash is being utilized as a recycling material for catalysis due to its aluminosilicate content. Catalytic conversion of polymeric wastes into synthetic gasoline and diesel through pyrolysis requires applicati...Coal fly ash is being utilized as a recycling material for catalysis due to its aluminosilicate content. Catalytic conversion of polymeric wastes into synthetic gasoline and diesel through pyrolysis requires application of kinetic and thermodynamic principles. This study aimed to identify the catalytic rate constant necessary for rate law involved in reaction mechanisms and activation energy reduction needed for heat transfer rate. Stoichiometric application for balanced total series of elementary reactions is solved for the concentration determination of reactants and products. Unsteady-state in three dimensional directions of thermodynamics is derived for the determination of heat transfer rate, temperatures at any position in a sphere using Gurney and Lurie chart and center temperature in a sphere by Heisler chart. Application principles of rate law and Arrhenius equation can result to thermal conductivity as a function of activation energy leading to synthetic fuel production.展开更多
基金financial support from the National Natural Science Foundation of China (21838004)Priority Academic Program Development of Jiangsu Higher Education Institutions (PPZY2015A044)Top-notch Academic Programs Project of Jiangsu Higher Education Institution (TAPP)。
文摘Struvite(MAP)crystallization technology is widely used to treat ammonia nitrogen in waste effluents of its simple operation and good removal efficiency.However,the presence of heavy metal ions in the waste effluents causes problems such as slow crystallization rate and small crystal size,limiting the recovery rate and economic value of the MAP.The present study was conducted to investigate the effects of concentrations of three heavy metal ions(Cu^(2+),Zn^(2+),and Pb^(2+))on the crystal morphology,crystal size,average growth rate,and crystallization kinetics of MAP.A relationship was established between the kinetic rate constant Ktcalculated by the chemical gradient model and the concentrations of heavy metal ions.The results showed that low concentrations of heavy metal ions in the solution created pits on the MAP surface,and high level of heavy metal ions generated flocs on the MAP surface,which were composed of metal hydroxides,thus inhibiting crystal growth.The crystal size,average growth rate,MAP crystallization rate,and kinetic rate constant Ktdecreased with the increase in heavy metal ion concentration.Moreover,the Ktdemonstrated a linear relationship with the heavy metal concentration ln(C/C~*),which provided a reference for the optimization of the MAP crystallization process in the presence of heavy metal ions.
基金The National Natural Science Foundation of China(No.20677067,20577064)the National Basic Research Program(973) of China(2005CB422206)
文摘Absolute rate constants for the reaction of ozone with dimethyl sulfide (DMS) were measured in a 200-L Teflon chamber over the temperature range of 283-353 K. Measurements were carried out using DMS in large excess over ozone of 10 to 1 or greater. Over the indicated temperature range, the data could be fit to the simple Arrhenius expression as kDMS = (9.96 ± 3.61) × 10^-11 exp (-(7309.7 ± 1098.2)/T) cm^3/(molecule.s). A compared investigation of the reaction between ozone and ethene had a kC2H4 value of (1.35 ± 0.11) × 10^-18 cm^3/(molecule.s) at room temperature.
基金Supported by the State Key Program of NNSFC (No. 20737001)NNSFC (No. 20977044)
文摘Structural and thermodynamic parameters of 16 chloro-phenol compounds in water solution were calculated and fully optimized by using Onsager model in self-consistent reaction field(SCRF) based on the B3LYP/6-311G** level.These quantum chemical parameters were used as theoretical descriptors to correlate with the experimental biodegradation rate constant(Kb) of 16 compounds by stepwise multiple linear regression.As a result,a three-parameter model including molecular average polarizability(α),entropy(Sθ),and molar heat capacity at constant volume(CVθ) were established for Kb prediction,which was proposed with correlation coefficient R2 = 0.894.α exhibits the most significant effect on Kb.Variance analysis and standard t-value test were applied to validate the model.As expected,this model exhibits good robustness and prediction ability,which can be used in Kb prediction of analogs.
基金supported by the National Natural Science Foundation of China (Nos. 50834007, 50874128, and 50674012)
文摘A simple model for estimating the rate constant between CO2-CO gas and molten slag containing iron oxides was developed using optical basicity only. In this model, the temperature dependence of the rate constant can be described by the Arrhenius law, and the activation energy can be expressed with a linear function of the slag's optical basicity. The model was applied to some molten slag systems, such as FeO, FeO-CaO, FeO-SiO2, FeO-Na2O, FeO-CaO-SiO2, FeO-SiO2-P2O5, FeO-SiOE-Na2O, and FeO-CaO-SiOE-P2O5. A comparison between the predicted results and measured data showed that the model worked well.
文摘Basing on the DFT calculations we propose the new theoretical model which describes both the surface tension σ of the short chain n-alkanes at their normal boiling points and their reaction rate constants with hydroxyl radicals OH<span style="white-space:nowrap;">•</span> (at 297 ± 2 K) on the basis of their molecular orbital electronic characteristics. It has been shown that intermolecular dispersion attraction within the surface liquid monolayer of these compounds, as well as their reaction rate constants k with OH<span style="white-space:nowrap;">•</span> radicals are determined by the energies <em>E<sub>orb</sub></em> of the specific occupied molecular orbitals which are the same in the determination of both the above physico-chemical characteristics of the studied n-alkanes. The received regression equations confirm the theoretically found dependences between the quantities of σ and k and the module |<em>E<sub>orb</sub></em>|. For the compounds under study this fact indicates the key role of their electronic structure particularities in determination of both the physical (surface tension) and the chemical (reaction rate constants) properties.
基金supported by the Jilin University,China(Grant No.419080106440)the Chinese National Fusion Project for the International Thermonuclear Experimental Reactor(ITER)(Grant No.2010GB104003)the National Natural Science Foundation of China(Grant No.10974069)
文摘A quasi-classical trajectory(QCT) calculation is used to investigate the vector and scalar properties of the D + Br O → DBr + O reaction based on an ab initio potential energy surface(X1A state) with collision energy ranging from 0.1 kcal/mol to 6 kcal/mol. The reaction probability, the cross section, and the rate constant are studied. The probability and the cross section show decreasing behaviors as the collision energy increases. The distribution of the rate constant indicates that the reaction favorably occurs in a relatively low-temperature region(T 〈 100 K). Meanwhile, three product angular distributions P(θr), P(φr), and P(θr, φr) are presented, which reflect the positive effect on the rotational angular momentum j' polarization of the DBr product molecule. In addition, two of the polarization-dependent generalized differential cross sections(PDDCSs), PDDCS00 and PDDCS20, are computed as well. Our results demonstrate that both vector and scalar properties have strong energy dependence.
文摘Rate constants for the reactions of NO3 and SO4 radicals with oxalic acid and oxalate anions in aqueous solution have been measured using pulse radiolysis and laser flash photolysis.
基金supported by the the National Natural Science Foundation of China(No.21373025 and 20933001)the Research Foundation of Education Bureau of Hebei Province(No.Z2011115)+3 种基金the 111 Project of China(No.B07012)the Natural Science Foundation of Hebei Province(No.B2012105002)the Research Foundation of Tangshan Administration of Science&Technology(131302115b)the Research Foundation of Tangshan normal college(2013A04)
文摘A dynamic method is employed to study the reaction mechanisms of CH3CH2OCF3 with the hydrogen trioxy (HOOO) radical. In our paper, the geometries and harmonic vibrational frequencies of all the stationary points and minimum energy paths (MEPs) are calculated at the MPW1K/6-31+G(d,p) level of theory, and the energetic information along MEPs is further refined by the CCSD/6-31+G(df, p) level of theory. The rate constants are evaluated with the conventional transition-state theory (TST), the canonical variational transition-state theory (CVT), the microcanonical variational transition-state theory (μVT), the CVT coupled with the small-curvature tunneling (SCT) correction (CVT/SCT), and the μVT coupled with the Eckart tunneling correction μVT/Eckart) based on the ab initio calculations in the temperature range of 200-3000 K. The theoretical results are important in determining the atmospheric lifetime and the feasible pathways for the loss of HFEs.
基金Project supported by National Natural Science Foundation of China (Grant No, 20406016)
文摘The application of Monte Carlo method in estimating rate constants for polymerization was described, A general program for Monte Carlo simulation was determined first according to the elementary reactions, after which the rate constants could be automatically adjusted and optimized through comparing of experimental and simulated data with an error expression that meeted a given minimum criterion. Such a process made the rate constants to be estimated without kinetic model in advance. The technique was applied to estimate the rate constants of the bulk polymerization of styrene catalyzed by the rare earth catalyst. The esthnated results showed the Monte Carlo method was feasible and effective for estimating rate constants in polymerization engineering.
文摘A new approach was employed to calculate the canonical (thermal) rate constant basedon unified statistical theory. All information for the calculation was obtained from ab initio meth-ods. The flux integral for any point of reaction coordinate was calculated by counting the numberof quantum states and applied to determine the dividing surfaces along the intrinsic reaction coor-dinate (IRC). The classical exchange reaction H2+H, as an example, was investigated. The IRC forthe reaction has been traced and detailed information of IRC was carried out at the QCISD/6-311 G** level .The calculated rate constants are well consistent with the experimental results.
文摘After the electron transfers from the metal electrode to the Fe3+(H2O)(6) ion, the free energy of activation of this electron transfer reaction is calculated, then using the transition probability which is calculated by the perturbed degeneration theory and the Fermi golden rule,, the rate constant is gotten. Compared with the experimental results, it is satisfactory.
文摘The new theoretical models describe both the solubility S of the shot chain n-alkanes in water at 298.15 K, and their reaction rate constants k with nitronium cation NO<sub>2</sub><sup>+ </sup>at 293.15 K on the basis of their molecular orbital characteristics. It is shown that both the quantities S and k are determined by the energies E<sub>orb</sub> of the specific virtual (for S) and occupied (for k) molecular orbitals of these n-alkanes. The obtained regression equations confirm the theoretically found dependences of S and k on the absolute value of E<sub>orb</sub>. This fact demonstrates that the electronic structure particularities of the studied n-alkanes play a crucial role in both their above-mentioned physicochemical properties.
文摘The transition state(TS) and Intrinsic Reaction Coordinate (IRC) for the titled reaction were traced by means of MCSCF/6-31G (210 configurations). The reaction activation energy of this reaction is 140.2KJ/mol. The reaction rate constants of five temperetures were calculated by CVT involving the tunneling effects.
文摘A single-sweep oscillopolarographic procedure is descrital which allows detethenahon of rateconstants for reachons of oH. For a wide range of compounds, the results fit well with rate constantspreviously obtained with other methods. Rate constants for reactions of six kinds of active compoundscontalned in rheum, a tradihonal Chinese herb, have been deteboned by this method. Rcationmechanism ha5 also been discussed.
基金financed by the Natural Science Foundation of Shaanxi Province(2014JM2046,2013JQ2027)the Special Natural Science Foundation of Science and Technology Bureau of Xi’an City Government(CXY1443WL03,CXY1352WL19 and CXY1352WL20)+1 种基金National Science Foundation of China(21303135)the Industrial research project of Science and Technology Department of Shaanxi Province(2013K09-25)
文摘The kinetics and mechanisms of H abstraction reaction between isoflurane and a CI atom have been investigated using DFT and G3(MP2) methods of theory. The geometrical structures of all species were optimized by the wB97XD/6-311++G** method. Intrinsic reaction coordinate (IRC) analysis has been carried out for the reaction channels. Thermochemistry data have been obtained by utilizing the high accurate model chemistry method G3(MP2) combined with the standard statistical thermodynamic calculations. Gibbs free energies were used for reaction channels analysis. Two channels were obtained, which correspond to P(1) and P(2). The rate constants for the two channels over a wide temperature range of 200-2000 K were also obtained. The results show that the barriers of P(1) and P(2) reaction channels are 50.36 and 50.34 kJ/mol, respectively, predicting that it exists two competitive channels. The calculated rate constant is in good agreement with the experiment value. Additionally, the results also show that the rate constants also increase from 1.85x10^-16 to 2.16x 10^12 cm3.moleculel.s-1 from 200 to 2000 K
基金Supported by the Eleventh Five Year National Key Technology R&D Program (2008BAE58B01)New Century Excellent Talents of Ministry of Education (NCET-07-0577),the People’s Republic of China
文摘实验方程适合的一个运动模型被建议了描述液体排水行为。率常数(k <sub > 液体排水方程的 d </sub>) 能从上述实验方程被获得。在这篇论文,胶体的煤气的 aphrons ( CGA )的稳定性,钠 dodecyl 苯硫酸盐( SDBS )的集中的效果, dodecyl trimethylammonium 溴化物( HTAB )和 polyoxyethylene 山梨糖醇酐 monolaurate ( Tween-20 ),温度,激动人心的速度,激动人心的时间,并且 k <sub 上的盐的各种各样的类型>液体排水的 d </sub>进一步被调查。结果证明 Arrhenius 方程能成功地被用来描述在 k <sub 之间的关系 > d </sub> 和绝对温度(T) ,和表面活化剂,激动人心的速度,激动人心的时间和咸度的集中也在 k <sub 上有大效果 > d </sub> 。最后, CGA 排水机制作为时间的功能从液体排水的率的分析被解释。
基金Supported by the National Natural Science Foundation of China (No. 20076022).
文摘A new method,which correlates rate constants of chemical reactions and density or pressure in supercritical fluids,was developed.Based on the transition state theory and thermodynamic principles, the rate constant can be reasonably correlated with the density of the supercritical fluid,and a correlation equation was obtained. Coupled with the equation of state (EOS) of a supercritical solvent,the effect of pressure on reaction rate constant could be represented.Two typical systems were used to test this method.The result indicates that this method is suitable for dilute supercritical fluid solutions.
文摘The density of fine coal has a major effect on the value of its flotation rate constant. The collector dose can increase the flotation rate of fine coal, especially for low ash coal, but the effect for gangue is not notable. The flotation rate of gangue is mainly governed by the water entrainment. A coal flotation rate constant model has been developed.
文摘Coal fly ash is being utilized as a recycling material for catalysis due to its aluminosilicate content. Catalytic conversion of polymeric wastes into synthetic gasoline and diesel through pyrolysis requires application of kinetic and thermodynamic principles. This study aimed to identify the catalytic rate constant necessary for rate law involved in reaction mechanisms and activation energy reduction needed for heat transfer rate. Stoichiometric application for balanced total series of elementary reactions is solved for the concentration determination of reactants and products. Unsteady-state in three dimensional directions of thermodynamics is derived for the determination of heat transfer rate, temperatures at any position in a sphere using Gurney and Lurie chart and center temperature in a sphere by Heisler chart. Application principles of rate law and Arrhenius equation can result to thermal conductivity as a function of activation energy leading to synthetic fuel production.