本文通过微波法超快速制备了泡沫镍(NF)负载的Co/Zn复合氧化物(Co-Zn/NF)。XRD测试表明生成的Co/Zn复合氧化物具有低结晶度。采用线性扫描伏安法(LSV)测试了Co-Zn/NF在碱性条件下的电催化硫离子氧化性能。与泡沫镍负载的单金属氧化物(Co...本文通过微波法超快速制备了泡沫镍(NF)负载的Co/Zn复合氧化物(Co-Zn/NF)。XRD测试表明生成的Co/Zn复合氧化物具有低结晶度。采用线性扫描伏安法(LSV)测试了Co-Zn/NF在碱性条件下的电催化硫离子氧化性能。与泡沫镍负载的单金属氧化物(Co/NF和Zn/NF)相比,Co-Zn/NF表现出更好的催化性能。在含有1 mol·L^(-1)Na2S和1 mol·L^(-1)NaOH的电解液中,Co-Zn/NF达到100 m A·cm^(-2)的电流密度所需的电位仅为0.28 V vs RHE,并且在恒定100 m A·cm^(-2)的电流密度下,长时间工作35小时后仍保持高的催化性能。此外,组装非对称电解槽(阳极:硫离子氧化反应(sulfion oxidation reaction,SOR)用1 mol·L^(-1)Na2S和1mol·L^(-1)NaOH为电解质,阴极:析氢反应(hydrogen evolution reaction,HER)用1 mol·L^(-1)Na OH为电解质)进行双电极硫氧化辅助电解水制氢测试,与传统的碱性电解水相比,达到100 m A·cm^(-2)电流密度所需的能耗降低了46%。本工作为低能耗电化学制氢提供了一种新思路,并证明了SOR耦合HER电解水制氢具有实际应用的可行性。展开更多
Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility ...Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility feature of some carbonate solvents also makes them very promising for overcoming the shuttle effects of LSBs.However,regular sulfur electrodes experience undesired electrochemical mechanisms in carbonate electrolytes due to side reactions.In this study,we report a catalytic redox mechanism of sulfur in propylene carbonate(PC)electrolyte based on a compari-son study.The catalytic mechanism is characterized by the interactions between polysulfides and dual N/O functional groups on the host carbon,which largely prevents side reactions between polysulfides and the carbonate electrolyte.Such a mechanism coupled with the low-polysulfide-solubility feature leads to stable cycling of LSBs in PC electrolyte.Favorable dual N/O functional groups are identified via a density functional theory study.This work provides an alternative route for enabling LSBs in carbonate electrolytes.展开更多
Removal of SO2 and NOx by pulsed corona combined with in situ alkali absorption was experimentally investigated.In the reactor,a plate-wire-plate combination is devised for generating pulsed corona and then alkaline a...Removal of SO2 and NOx by pulsed corona combined with in situ alkali absorption was experimentally investigated.In the reactor,a plate-wire-plate combination is devised for generating pulsed corona and then alkaline absorbent slurries were introduced into the reactor by a continuous band conveying system to capture the gaseous reaction products.It was found that both SO2 and NO could be removed by corona combined with in situ alkali absorption.The removal of SO2 increased to 75%with the corona discharge,compared with 60%removal only with Ca(OH)2 absorption.About 40%removal of NO was reached by pulsed corona combined with in situ Ca(OH)2 absorption.It was found that SO2 and NO in the gas stream are oxidized to SO3 and NO2 by pulsed corona respectively,and then absorbed by the alkali in the reactor.The removals of SO2 as well as NO were higher with Ca(OH)2 as the absorbent,compared with using CaCO3 or ZnO.展开更多
Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample.Sulfuric acid pressure leaching of zinc silicate ore was carried out to ...Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample.Sulfuric acid pressure leaching of zinc silicate ore was carried out to assess the effect of particle size,sulfuric acid concentration,pressure,reaction time and temperature on the extraction of zinc and the dissolution of silica.Under the optimum conditions employed,up to 99.25% of zinc extraction and 0.20% silica dissolution are obtained.The main minerals in leaching residue are quartz and small amounts of undissolved oxide minerals of iron,lead and aluminum are associated with quartz.展开更多
The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of var...The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.展开更多
To study the mechanism of SO2 and Hg removal from flue gas, an experimental packed bed reactor was designed to simulate the dry FGD, where a mixture of lime and fly ash in ratio 1:3 w/w was used as the S02 and Hg sor...To study the mechanism of SO2 and Hg removal from flue gas, an experimental packed bed reactor was designed to simulate the dry FGD, where a mixture of lime and fly ash in ratio 1:3 w/w was used as the S02 and Hg sorbent, and steam at temperature of 100 ℃ was applied for activation of the sorbent, while the activation time set to 20 rain. The experimental factors including the SO2/Hg sorbent characteristics, 50% breakthrough time for SO2/Hg removal, sorbent packed bed depth and reaction temperature were investigated. The experimental results show that after steam activation, the BET specific surface area and specific pore volume increased from 37.8 to 45.5 m^2/g and from 0.42 to 0.51 cm^3/g, respectively. With activation of the sorbent by steam, the 50% breakthrough times of SO2 and Hg removal increased from 34 to 42 rain and from 23 to 45 rain, respectively. When the packed bed depth was increased from 5 to 25 ram. the 50% breakthrough times for Hg and S02 removal increased from 12 to 52 rain and from 6 to 47 rain, respectively. With the increase of the reaction temperature, the 50% breakthrough of SO2/Hg removal decreased accordingly. Steam activation can efficiently improve SO2/Hg removal simultaneously.展开更多
A photocatalyst Cu-BiVO4 was synthesized by the hydrothermal method and was characterized by XRD, UV-vis DRS, and N2 adsorption-desorption measurement. The catalytic activity of the Cu-BiVO4 samples was studied on des...A photocatalyst Cu-BiVO4 was synthesized by the hydrothermal method and was characterized by XRD, UV-vis DRS, and N2 adsorption-desorption measurement. The catalytic activity of the Cu-BiVO4 samples was studied on desulfurization of thiophene dissolved in n-octane, which was used as a model light oil, via photocatalytic oxidation reaction under illumination by visible light. The catalyst characterization results indicated that the loading of Cu on the catalyst did not change the crystal phase of BiVO4, and the crystallinity of the Cu-BiVO4 sample was found to be better at pH=7. The Cu-BiVO4 samples presented a significant bathochromic shift of the absorption band in the visible region, and the absorption intensity increased for the composite catalyst. The desulfurization experiments showed that the Cu-BiVO4 sample prepared at a pH value of 7 had a better catalytic activity. Under proper operating conditions, the desulfurization rate of the model compound achieved by Cu-BiVO4 sample prepared at pH=7 could reach as high as 90%.展开更多
In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynami...In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynamics of PbSO4 was calculated by software HSC 5.0. The effects of gas concentration, reaction temperature, time and mass of sample on reduction of PbSO4 were examined by thermogravimetry(TG) and XRD. Roasting tests further verify the conclusions of thermodynamic and TG analyses. The results show that increasing temperature in the reasonable range and CO content are favorable for the formation of Pb S. The reduction process is controlled by chemical reaction and calculation value of the activation energy is 47.88 k J/mol.展开更多
The leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate was studied.The effects including leaching temperature, reaction time, particle size, stirring speed, and concen...The leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate was studied.The effects including leaching temperature, reaction time, particle size, stirring speed, and concentrations of sulfuric acid and sodium peroxodisulfate were investigated. The leaching process of molybdenum from Ni-Mo ore is controlled by the chemical reaction through the solid layer across the unreacted shrinking core. The apparent activation energy of the leaching of molybdenum is calculated to be 41.0 k J/mol and the leaching kinetics equation of molybdenum from Ni-Mo ore is expressed as1-(1-a)1/3=3405.7exp[-41030.0/(RT)]t.展开更多
A range of ferrocenyl sulfides are synthesized and screened. Among them l-a-methysulphoferrocenyl ethyl acetate and l-a-methysulphoferrocenyl alcohol are found to be unexpected catalysts, which is first reported media...A range of ferrocenyl sulfides are synthesized and screened. Among them l-a-methysulphoferrocenyl ethyl acetate and l-a-methysulphoferrocenyl alcohol are found to be unexpected catalysts, which is first reported mediating in sulfur ylide epoxidation reactions, furnishing a novel approach for highly stereoselective synthesis of oxiranes with 98%-100% trans-isomer. The protocol also has excellent yield, convenient workup and recycled starting material. The reason of high trans-selectivity is due to the bulky ferrocenyl sulfide group, which stabilizes the intermediates and determines the trans priority. A possible catalytic mechanism is also proposed.展开更多
Hydroxyl radicals HO are generated under Fenton-like (Fe2++H2O2→HO?+OH?+Fe3+) catalytic conditions upon microwave irradiation. Liquid-phase direct catalytic oxidation of benzene to phenol was obtained using FeSO4 sup...Hydroxyl radicals HO are generated under Fenton-like (Fe2++H2O2→HO?+OH?+Fe3+) catalytic conditions upon microwave irradiation. Liquid-phase direct catalytic oxidation of benzene to phenol was obtained using FeSO4 supported on silica gel as a solid catalyst and hydrogen peroxide as the oxidant. The effects of various parameters, such as the different solvents, the amount of solvent used, the amount of catalyst used, the reaction time, the reaction temperature and the amount of hydrogen peroxide used on the yield of phenol were studied to identify optimum reaction conditions. Conventionally heated reaction gives a phenol yield of 0.6%. A higher phenol yield of 13.9% with a selectivity of 100% is obtained when the reaction mixture was irradiated with micro-wave energy. It is concluded that microwave irradiation offers more effective control of energy input for hydroxyl radical generation that is appropriate for various synthetic reactions.展开更多
A convenient and effective procedure was developed for the conversion of alcohol to olefin by tosylation and subsequent β-elimination promoted by silica gel in this study. Treatment of the alcohols with p-toluenesulf...A convenient and effective procedure was developed for the conversion of alcohol to olefin by tosylation and subsequent β-elimination promoted by silica gel in this study. Treatment of the alcohols with p-toluenesulfonyl chloride in pyridine at 0℃ af- fords tosylates which undergo β-elimination with silica gel in dichloromethane or chloroform at room temperature, yielding olefins with high productivity.展开更多
The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that ...The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that in 0.1 mol/L HClO4. It is found that adsorbed sulfate has significant inhibition effect on FAO kinetics. After addition of 0.05 mol/L or 0.1 mol/L Na2SO4, FAO current in the negative-going scan is found to be significantly smaller than that at the same potential in the positive-going scan. We speculate that at potentials positive of the phase transition potential for the (SO4*ad)m+[(H2O)n-H3O+] or(SO4*ad)m+[Na+(H2O)n-H3O+] adlayer, the adlayer structure probably becomes denser and more stable with the increase of potential or with the addition of Na2SO4. The formation of connected adlayer network greatly enhance the stability of the adlayer, and the insertion of positive-charged H+ or Na+ into the adlayer network further reduces the electrostatic repulsion between partially charged sulfates. As a result, the destruction/desorption of compact sulfate adlayer becomes more difficult, which leaves much less free sites on the surface for FAO, and thus FAO kinetics at higher potentials and in the subsequent negative-going potential scan is significantly inhibited.展开更多
The mechanism of the leaching process of chalcopyrite concentrate with sodium nitrate in sulphuric acid solution were studied and discussed. Chemical reactions of leaching and their thermodynamic probabilities are pre...The mechanism of the leaching process of chalcopyrite concentrate with sodium nitrate in sulphuric acid solution were studied and discussed. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the calculated Gibbs energies and analysis of E-pH diagrams. Experimental data, thermodynamic analysis, chemical, XRD, and SEM/EDX analyses of concentrate and the leach residues, were performed to develop a better understanding of the chemical reactions that took place in the system. Elemental sulphur was formed as the main leaching product, precipitated at the particle surfaces and tended to inhibit the leaching rate.展开更多
Electrochimcal behaviors of rusticyanin (Rus.) isolated from Acidithiobacillus ferrooxidans were investigated through Rus.-ZnS-QDs/L-Cys/Au electrode. The cyclic voltammetric results indicate that rusticyanin immobi...Electrochimcal behaviors of rusticyanin (Rus.) isolated from Acidithiobacillus ferrooxidans were investigated through Rus.-ZnS-QDs/L-Cys/Au electrode. The cyclic voltammetric results indicate that rusticyanin immobilized on the surface of Rus.-ZnS-QDs/L-Cys/Au electrode can undergo a direct quasi-reversible electrochemical reaction. The immobilized rusticyanin is not denatured and still retains its activity in the temperature range of 19-43 ℃. The reduction ability of the protein increases and its oxidation ability becomes weak with the increase of pH from 6.0 to 7.8. Fe^2+ ions in the solution can promote the electron transfer kinetics of the immobilized rusticyanin and make its peak potentials (φp) markedly move negatively.展开更多
文摘本文通过微波法超快速制备了泡沫镍(NF)负载的Co/Zn复合氧化物(Co-Zn/NF)。XRD测试表明生成的Co/Zn复合氧化物具有低结晶度。采用线性扫描伏安法(LSV)测试了Co-Zn/NF在碱性条件下的电催化硫离子氧化性能。与泡沫镍负载的单金属氧化物(Co/NF和Zn/NF)相比,Co-Zn/NF表现出更好的催化性能。在含有1 mol·L^(-1)Na2S和1 mol·L^(-1)NaOH的电解液中,Co-Zn/NF达到100 m A·cm^(-2)的电流密度所需的电位仅为0.28 V vs RHE,并且在恒定100 m A·cm^(-2)的电流密度下,长时间工作35小时后仍保持高的催化性能。此外,组装非对称电解槽(阳极:硫离子氧化反应(sulfion oxidation reaction,SOR)用1 mol·L^(-1)Na2S和1mol·L^(-1)NaOH为电解质,阴极:析氢反应(hydrogen evolution reaction,HER)用1 mol·L^(-1)Na OH为电解质)进行双电极硫氧化辅助电解水制氢测试,与传统的碱性电解水相比,达到100 m A·cm^(-2)电流密度所需的能耗降低了46%。本工作为低能耗电化学制氢提供了一种新思路,并证明了SOR耦合HER电解水制氢具有实际应用的可行性。
文摘Carbonate electrolytes are one of the most desirable electrolytes for high-energy lithium-sulfur batteries(LSBs)because of their successful implementation in commercial Li-ion batteries.The low-polysulfide-solubility feature of some carbonate solvents also makes them very promising for overcoming the shuttle effects of LSBs.However,regular sulfur electrodes experience undesired electrochemical mechanisms in carbonate electrolytes due to side reactions.In this study,we report a catalytic redox mechanism of sulfur in propylene carbonate(PC)electrolyte based on a compari-son study.The catalytic mechanism is characterized by the interactions between polysulfides and dual N/O functional groups on the host carbon,which largely prevents side reactions between polysulfides and the carbonate electrolyte.Such a mechanism coupled with the low-polysulfide-solubility feature leads to stable cycling of LSBs in PC electrolyte.Favorable dual N/O functional groups are identified via a density functional theory study.This work provides an alternative route for enabling LSBs in carbonate electrolytes.
基金Supported by the Science and Technology Development Project of Zhejiang Province(2007C13085)Hangzhou City(20070733B28)
文摘Removal of SO2 and NOx by pulsed corona combined with in situ alkali absorption was experimentally investigated.In the reactor,a plate-wire-plate combination is devised for generating pulsed corona and then alkaline absorbent slurries were introduced into the reactor by a continuous band conveying system to capture the gaseous reaction products.It was found that both SO2 and NO could be removed by corona combined with in situ alkali absorption.The removal of SO2 increased to 75%with the corona discharge,compared with 60%removal only with Ca(OH)2 absorption.About 40%removal of NO was reached by pulsed corona combined with in situ Ca(OH)2 absorption.It was found that SO2 and NO in the gas stream are oxidized to SO3 and NO2 by pulsed corona respectively,and then absorbed by the alkali in the reactor.The removals of SO2 as well as NO were higher with Ca(OH)2 as the absorbent,compared with using CaCO3 or ZnO.
基金Project(2007CB613605) supported by the National Basic Research Program of China
文摘Zinc silicate ore was characterized mineralogically and the results showed that zinc exists mainly as hemimorphite and smithsonite in the sample.Sulfuric acid pressure leaching of zinc silicate ore was carried out to assess the effect of particle size,sulfuric acid concentration,pressure,reaction time and temperature on the extraction of zinc and the dissolution of silica.Under the optimum conditions employed,up to 99.25% of zinc extraction and 0.20% silica dissolution are obtained.The main minerals in leaching residue are quartz and small amounts of undissolved oxide minerals of iron,lead and aluminum are associated with quartz.
基金Supported by the R&D center of Esfahan refinery (Esfahan,Iran)the technical supports of central laboratory of Esfahan Refinery for total sulfur analysis
文摘The oxidative desulfurization of a real refinery feedstock (i.e.,non-hydrotreated kerosene with total sulfur mass content of 0.16%) with a mixture of hydrogen peroxide and acetic acid was studied.The influences of various operating parameters including reaction temperature (T),acid to sulfur molar ratio (nacid/nS),and oxidant to sulfur molar ratio (nO/nS) on the sulfur removal of kerosene were investigated.The results revealed that an increase in the reaction temperature (T) and nacid/nS enhances the sulfur removal.Moreover,there is an optimum nO/nS related to the reaction temperature and the best sulfur removal could be obtained at nO/nS=8 and 23 for the reaction temperatures of 25 and 60°C,respectively.The maximum observed sulfur removal in the present oxidative desulfurization system was 83.3%.
基金supported by the National High-Tech R&D Program of China (No. 2008AA06Z318)the Ministry of Environmental Protection of China (Nos. 201009048 and 200909025)
文摘To study the mechanism of SO2 and Hg removal from flue gas, an experimental packed bed reactor was designed to simulate the dry FGD, where a mixture of lime and fly ash in ratio 1:3 w/w was used as the S02 and Hg sorbent, and steam at temperature of 100 ℃ was applied for activation of the sorbent, while the activation time set to 20 rain. The experimental factors including the SO2/Hg sorbent characteristics, 50% breakthrough time for SO2/Hg removal, sorbent packed bed depth and reaction temperature were investigated. The experimental results show that after steam activation, the BET specific surface area and specific pore volume increased from 37.8 to 45.5 m^2/g and from 0.42 to 0.51 cm^3/g, respectively. With activation of the sorbent by steam, the 50% breakthrough times of SO2 and Hg removal increased from 34 to 42 rain and from 23 to 45 rain, respectively. When the packed bed depth was increased from 5 to 25 ram. the 50% breakthrough times for Hg and S02 removal increased from 12 to 52 rain and from 6 to 47 rain, respectively. With the increase of the reaction temperature, the 50% breakthrough of SO2/Hg removal decreased accordingly. Steam activation can efficiently improve SO2/Hg removal simultaneously.
基金supported by the National Natural Science Foundation of China (No. 21003103)the Nature Scientific Research Foundation of Shaanxi Provincial Education Office of China (No. 2010JS061)Natural Science Foundation Program of Yan’an University (YD2011-19)
文摘A photocatalyst Cu-BiVO4 was synthesized by the hydrothermal method and was characterized by XRD, UV-vis DRS, and N2 adsorption-desorption measurement. The catalytic activity of the Cu-BiVO4 samples was studied on desulfurization of thiophene dissolved in n-octane, which was used as a model light oil, via photocatalytic oxidation reaction under illumination by visible light. The catalyst characterization results indicated that the loading of Cu on the catalyst did not change the crystal phase of BiVO4, and the crystallinity of the Cu-BiVO4 sample was found to be better at pH=7. The Cu-BiVO4 samples presented a significant bathochromic shift of the absorption band in the visible region, and the absorption intensity increased for the composite catalyst. The desulfurization experiments showed that the Cu-BiVO4 sample prepared at a pH value of 7 had a better catalytic activity. Under proper operating conditions, the desulfurization rate of the model compound achieved by Cu-BiVO4 sample prepared at pH=7 could reach as high as 90%.
基金Project(51204210)supported by the National Natural Science Foundation of ChinaProject(2011AA061001)supported by the National High Technology Research and Development Program of ChinaProject(2012BAC12B04)supported by the National Science and Technology Pillar Program during the Twelfth Five-Year Plan of China
文摘In order to decrease the solubility of PbSO4 and enhance lead recovery from PbSO4 bearing wastes, CO was employed as a reductant to transform PbSO4 into Pb S. Reaction system was established and reductive thermodynamics of PbSO4 was calculated by software HSC 5.0. The effects of gas concentration, reaction temperature, time and mass of sample on reduction of PbSO4 were examined by thermogravimetry(TG) and XRD. Roasting tests further verify the conclusions of thermodynamic and TG analyses. The results show that increasing temperature in the reasonable range and CO content are favorable for the formation of Pb S. The reduction process is controlled by chemical reaction and calculation value of the activation energy is 47.88 k J/mol.
基金Project(51364009) supported by the National Natural Science Foundation of ChinaProject(JSU071302) supported by the Construct Program of the Key Discipline in Hunan Province,ChinaProject(2015JJ2115) supported by the Natural Science Foundation of Hunan Province,China
文摘The leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid solution with sodium peroxodisulfate was studied.The effects including leaching temperature, reaction time, particle size, stirring speed, and concentrations of sulfuric acid and sodium peroxodisulfate were investigated. The leaching process of molybdenum from Ni-Mo ore is controlled by the chemical reaction through the solid layer across the unreacted shrinking core. The apparent activation energy of the leaching of molybdenum is calculated to be 41.0 k J/mol and the leaching kinetics equation of molybdenum from Ni-Mo ore is expressed as1-(1-a)1/3=3405.7exp[-41030.0/(RT)]t.
基金Project supported by the National Natural Science Foundation of China (No. 29972036) and the Postdoctoral Science Foundation of China (No. 2003033537)
文摘A range of ferrocenyl sulfides are synthesized and screened. Among them l-a-methysulphoferrocenyl ethyl acetate and l-a-methysulphoferrocenyl alcohol are found to be unexpected catalysts, which is first reported mediating in sulfur ylide epoxidation reactions, furnishing a novel approach for highly stereoselective synthesis of oxiranes with 98%-100% trans-isomer. The protocol also has excellent yield, convenient workup and recycled starting material. The reason of high trans-selectivity is due to the bulky ferrocenyl sulfide group, which stabilizes the intermediates and determines the trans priority. A possible catalytic mechanism is also proposed.
基金supported by the National Natural Science Foundation of China (No.50921002)
文摘Hydroxyl radicals HO are generated under Fenton-like (Fe2++H2O2→HO?+OH?+Fe3+) catalytic conditions upon microwave irradiation. Liquid-phase direct catalytic oxidation of benzene to phenol was obtained using FeSO4 supported on silica gel as a solid catalyst and hydrogen peroxide as the oxidant. The effects of various parameters, such as the different solvents, the amount of solvent used, the amount of catalyst used, the reaction time, the reaction temperature and the amount of hydrogen peroxide used on the yield of phenol were studied to identify optimum reaction conditions. Conventionally heated reaction gives a phenol yield of 0.6%. A higher phenol yield of 13.9% with a selectivity of 100% is obtained when the reaction mixture was irradiated with micro-wave energy. It is concluded that microwave irradiation offers more effective control of energy input for hydroxyl radical generation that is appropriate for various synthetic reactions.
文摘A convenient and effective procedure was developed for the conversion of alcohol to olefin by tosylation and subsequent β-elimination promoted by silica gel in this study. Treatment of the alcohols with p-toluenesulfonyl chloride in pyridine at 0℃ af- fords tosylates which undergo β-elimination with silica gel in dichloromethane or chloroform at room temperature, yielding olefins with high productivity.
基金supported by the National Natural Science Foundation of China(No.21872132 and No.21832004)973 Program from the Ministry of Science and Technology of China(No.201503932301)
文摘The kinetics of formic acid oxidation (FAO) on Pd(111) in 0.1 mol/L H2SO4+0.1 mol/L HCOOH with and without addition of Na2SO4 is studied using cyclic voltammetry and potential step method, which is compared with that in 0.1 mol/L HClO4. It is found that adsorbed sulfate has significant inhibition effect on FAO kinetics. After addition of 0.05 mol/L or 0.1 mol/L Na2SO4, FAO current in the negative-going scan is found to be significantly smaller than that at the same potential in the positive-going scan. We speculate that at potentials positive of the phase transition potential for the (SO4*ad)m+[(H2O)n-H3O+] or(SO4*ad)m+[Na+(H2O)n-H3O+] adlayer, the adlayer structure probably becomes denser and more stable with the increase of potential or with the addition of Na2SO4. The formation of connected adlayer network greatly enhance the stability of the adlayer, and the insertion of positive-charged H+ or Na+ into the adlayer network further reduces the electrostatic repulsion between partially charged sulfates. As a result, the destruction/desorption of compact sulfate adlayer becomes more difficult, which leaves much less free sites on the surface for FAO, and thus FAO kinetics at higher potentials and in the subsequent negative-going potential scan is significantly inhibited.
文摘The mechanism of the leaching process of chalcopyrite concentrate with sodium nitrate in sulphuric acid solution were studied and discussed. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the calculated Gibbs energies and analysis of E-pH diagrams. Experimental data, thermodynamic analysis, chemical, XRD, and SEM/EDX analyses of concentrate and the leach residues, were performed to develop a better understanding of the chemical reactions that took place in the system. Elemental sulphur was formed as the main leaching product, precipitated at the particle surfaces and tended to inhibit the leaching rate.
基金Project(2010CB630903) supported by the National Basic Research Program of ChinaProject(50621063) supported by the National Natural Science Foundation of China
文摘Electrochimcal behaviors of rusticyanin (Rus.) isolated from Acidithiobacillus ferrooxidans were investigated through Rus.-ZnS-QDs/L-Cys/Au electrode. The cyclic voltammetric results indicate that rusticyanin immobilized on the surface of Rus.-ZnS-QDs/L-Cys/Au electrode can undergo a direct quasi-reversible electrochemical reaction. The immobilized rusticyanin is not denatured and still retains its activity in the temperature range of 19-43 ℃. The reduction ability of the protein increases and its oxidation ability becomes weak with the increase of pH from 6.0 to 7.8. Fe^2+ ions in the solution can promote the electron transfer kinetics of the immobilized rusticyanin and make its peak potentials (φp) markedly move negatively.