β-Bromovinyl tellurides are new difuctional reagents which undergo palladium-catalyzed cross-coupling reaction with alkenes to give conjugated dienyl tellurides.
9-Chlorofluorene reacted with aromatic aldehydes and ketones in the presence of phase transfer catalyst, giving the Darzens condensation epoxy products.
Methyl 3-trimethylsilylpropargyl carbonate reacted with dinucleophiles under the catalysis of palladium(0) complex to give the corresponding desilylated annulation products.
The yield and stereoselectivity of the Diels-Alder reactions between furan(or 2-methylfuran)and different dienophiles are markedly enhanced by the catalysis of anhydrous YbCl_3.
The kinetics of reaction of bromo-epoxy resin with oleic acid in the presence of dimethylbenzylamine catalyst was studied. The reaction is a zero order reaction with respect to oleic acid, first order with respect to ...The kinetics of reaction of bromo-epoxy resin with oleic acid in the presence of dimethylbenzylamine catalyst was studied. The reaction is a zero order reaction with respect to oleic acid, first order with respect to epoxy group and 0. 74 order with respect to dimethylbenzylamine. The reaction rate constants at various temperatures and activation energy were determined. The mechanism of this reaction was discussed. Keywords Tetrabromobisphenol-A, Bromo-epoxy resin, Oleic acid kinetics, Reaction mechanism展开更多
To obtain new functional aromatic polymer materiul. 3,3＇-biacenaphthene, which is used as macromolecule intermediate of,funcrion aromatic polymer material, was synthesized through the coupling reaction of acenaphthen...To obtain new functional aromatic polymer materiul. 3,3＇-biacenaphthene, which is used as macromolecule intermediate of,funcrion aromatic polymer material, was synthesized through the coupling reaction of acenaphthene catalyzing by ionic liquid （[bmim]CI/FeCl3） at mild reaction condition. Pure 3,3＇-biacenaphthene was obtained hy recrystalling and column chromatography from the reaction mixture and was determined by GC/MS, SHNMR arid FTIR analysis. The influence of various reaction conditions on the yield of 3,3＇-biacenaphthene were studied by GC analysis. The result shows that the optimun synthesis conditions of the coupling reaction are, as following： the molar ratio of FeCl3 to [BmimlCl being 3, the mole ratio of FeCl3 in [Bmim]Cl/FeCl3 to acenaphthene being 4. the reaction temperamre being 20 ℃ the reaction time being 4h and the solvent of the reaction system being PhNO2 Under those conditions, the yield of the 3.3＇-biacenaphthene will be 48.71% and selectivity, of that will be 78.56 %. Farther more, [bmim]Cl/FeCl3 has no pollution to environments and can be reused.展开更多
The thermokinetic reduced extent equations of reversible inhibitions for Michaiels-Menten enzymatic reaction were deduced, and then the criteria for distingushing inhibition type was given and the methods for calculat...The thermokinetic reduced extent equations of reversible inhibitions for Michaiels-Menten enzymatic reaction were deduced, and then the criteria for distingushing inhibition type was given and the methods for calculating kinetic parameters, KM,Ki and Urn were suggested. This theory was applied to inverstigate the inhibited thermokinetics of laccase-catalyzed oxidation of o-dihydroxybenzene by m-dihydroxybenzene. The experimental results show the inhibition belongs to reversible competitive type, KM=6.224×10-3 mol L-1, Ki=2. 363 × 10-2 mol. L-1.展开更多
The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the ...The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the sintering of ZnS and FeS and used for the pressure acid leaching experiment.The variations in the potential of the pressure leaching system were investigated by using a self-designed potential autoclave.The results showed that compared to the non-iron sphalerite,there was a violent redox reaction between the 25.70%Fe-artificial sphalerite and dissolved oxygen during the process of pressure leaching;and the catalytic mechanism was attributed to the redox couple Fe^3+/Fe^2+,where Fe3+oxidizes the H2S gas film and the reduced Fe2+state is subsequently oxidized by the dissolved oxygen.Furthermore,the effect of temperature,H2SO4 concentration,and oxygen partial pressure on the artificial sphalerite with different iron contents was studied.The sphalerite samples with iron content were observed to dissolve more easily in sulfuric acid compared to the non-iron samples.Moreover,the activation energy of artificial sphalerite was observed to be lower in the sample with 25.70%iron content(22.26 kJ/mol)compared to that with no iron(32.31 kJ/mol);and the apparent reaction orders were obtained with respect to H2SO4 concentration(1.10 and 1.36)and oxygen partial pressure(1.29 and 1.41),respectively.A comprehensive kinetic model was developed on the basis of the experimental data and the fitted leaching ratio plot;and the kinetic equations for the leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation were determined.展开更多
Through the method of initial heat release rate, the kinetic property of tyrosine oxidation catalyzed by tyrosinase from Pseudomonas maltophilia was investigated using a LKB-2107 batch microcalorimeter. Tyrosine was c...Through the method of initial heat release rate, the kinetic property of tyrosine oxidation catalyzed by tyrosinase from Pseudomonas maltophilia was investigated using a LKB-2107 batch microcalorimeter. Tyrosine was catalyzed and oxidized into L-dopa, then into melanin catalyzed by tyrosinase. We found that the tyrosinase reaction obeyed the Michaelis-Menten kinetics, and at 298.15K and pH 7.0, the initial exothermic rate (W0 ) are in the range of 0.1567~0.5704 mJ·s-1, the maximum exothermic rate (Wmax) are in 0.4152 ~ 0.8143mol·L-1, and mean value of the Michaelis constant (Km) is 2.199±0.105104 mol·L-1.展开更多
A photoredox-catalyzed cascade carbon/carboxylation of activated alkenes with malonates acetals and CO_(2) has been achieved,leading to a range of functionalized 1,1,3-tricarboxylates in good efficiency under mild rea...A photoredox-catalyzed cascade carbon/carboxylation of activated alkenes with malonates acetals and CO_(2) has been achieved,leading to a range of functionalized 1,1,3-tricarboxylates in good efficiency under mild reaction conditions.This reaction provides a facile and sustainable method for the synthesis of tricarboxylates by using CO_(2) as the carboxylic source.展开更多
A mild and efficient photochemical multi-component tandem reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids is reported. This tandem reaction could be conveniently carried out at room temperature by employ...A mild and efficient photochemical multi-component tandem reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids is reported. This tandem reaction could be conveniently carried out at room temperature by employing 4Cz IPN as the metal-free photocatalyst and dioxygen(air) as the environmentally benign oxidant. A number of sulfonated quinoxalin-2(1H)-ones were obtained in satisfactory yields with favorable functional group tolerance. Radical trapping experiment and fluorescence quenching experiments were performed to elucidate this visible-light mediated radical reaction process.展开更多
An efficient and practical route to various 3-alkoxylquinoxalin-2(1 H)-ones through visible-light photocatalytic C(sp^2)-H/O-H cross-dehydrogenation coupling of quinoxalin-2(1 H)-ones and alcohols,employing ambient ai...An efficient and practical route to various 3-alkoxylquinoxalin-2(1 H)-ones through visible-light photocatalytic C(sp^2)-H/O-H cross-dehydrogenation coupling of quinoxalin-2(1 H)-ones and alcohols,employing ambient air as an oxidant at room temperature under metal-free conditions,was developed.展开更多
A new analytical method is proposed for the determination of heroin based on a sequential perturbation caused by trace amounts of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction between hydrogen peroxide and sodiu...A new analytical method is proposed for the determination of heroin based on a sequential perturbation caused by trace amounts of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction between hydrogen peroxide and sodium thiocyanate in an alkaline medium with the aid of a continuous-flow stirred tank reactor(CSTR). The method relies on the linear relationship between the change in oscillation period of the system and the concentration of heroin, with a detecting limit of 4.0×10^(-7) mol/L. The calibration curve fits a linear equation very well when the concentration of heroin is in the range of 2.0×10^(-6)_1.2×10^(-5) mol/L(r=0.9971). This method features good precision(RSD=0.98%). The influences of temperature, injection point, flow rate and reaction variables on the oscillation period were investigated in detail and a possible mechanism of the performance of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction system is also discussed. The proposed method opens a new avenue for the determination of heroin.展开更多
基金This work was supported by Natural Science Foundation of Zhejiang Province.
文摘β-Bromovinyl tellurides are new difuctional reagents which undergo palladium-catalyzed cross-coupling reaction with alkenes to give conjugated dienyl tellurides.
文摘9-Chlorofluorene reacted with aromatic aldehydes and ketones in the presence of phase transfer catalyst, giving the Darzens condensation epoxy products.
文摘Methyl 3-trimethylsilylpropargyl carbonate reacted with dinucleophiles under the catalysis of palladium(0) complex to give the corresponding desilylated annulation products.
文摘The yield and stereoselectivity of the Diels-Alder reactions between furan(or 2-methylfuran)and different dienophiles are markedly enhanced by the catalysis of anhydrous YbCl_3.
文摘The kinetics of reaction of bromo-epoxy resin with oleic acid in the presence of dimethylbenzylamine catalyst was studied. The reaction is a zero order reaction with respect to oleic acid, first order with respect to epoxy group and 0. 74 order with respect to dimethylbenzylamine. The reaction rate constants at various temperatures and activation energy were determined. The mechanism of this reaction was discussed. Keywords Tetrabromobisphenol-A, Bromo-epoxy resin, Oleic acid kinetics, Reaction mechanism
基金National Natural Science Foundation of China (No. 20207003)
文摘To obtain new functional aromatic polymer materiul. 3,3＇-biacenaphthene, which is used as macromolecule intermediate of,funcrion aromatic polymer material, was synthesized through the coupling reaction of acenaphthene catalyzing by ionic liquid （[bmim]CI/FeCl3） at mild reaction condition. Pure 3,3＇-biacenaphthene was obtained hy recrystalling and column chromatography from the reaction mixture and was determined by GC/MS, SHNMR arid FTIR analysis. The influence of various reaction conditions on the yield of 3,3＇-biacenaphthene were studied by GC analysis. The result shows that the optimun synthesis conditions of the coupling reaction are, as following： the molar ratio of FeCl3 to [BmimlCl being 3, the mole ratio of FeCl3 in [Bmim]Cl/FeCl3 to acenaphthene being 4. the reaction temperamre being 20 ℃ the reaction time being 4h and the solvent of the reaction system being PhNO2 Under those conditions, the yield of the 3.3＇-biacenaphthene will be 48.71% and selectivity, of that will be 78.56 %. Farther more, [bmim]Cl/FeCl3 has no pollution to environments and can be reused.
文摘The thermokinetic reduced extent equations of reversible inhibitions for Michaiels-Menten enzymatic reaction were deduced, and then the criteria for distingushing inhibition type was given and the methods for calculating kinetic parameters, KM,Ki and Urn were suggested. This theory was applied to inverstigate the inhibited thermokinetics of laccase-catalyzed oxidation of o-dihydroxybenzene by m-dihydroxybenzene. The experimental results show the inhibition belongs to reversible competitive type, KM=6.224×10-3 mol L-1, Ki=2. 363 × 10-2 mol. L-1.
基金Projects(51804136,51764016)supported by the National Natural Science Foundation of ChinaProject(U1402271)supported by the Joint Funds of the National Natural Science Foundation of China+2 种基金Project(20181BAB216017)supported by the Jiangxi Provincial Natural Science Foundation,ChinaProject(GK-201803)supported by the Research Fund Program of State Key Laboratory of Rare Metals Separation and Comprehensive Utilization,ChinaProjects(yy2016001,yy2016012)supported by the Research Fund Program of the State Key Laboratory of Pressure Hydrometallurgical Technology of Associated Nonferrous Metal Resources,China。
文摘The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the sintering of ZnS and FeS and used for the pressure acid leaching experiment.The variations in the potential of the pressure leaching system were investigated by using a self-designed potential autoclave.The results showed that compared to the non-iron sphalerite,there was a violent redox reaction between the 25.70%Fe-artificial sphalerite and dissolved oxygen during the process of pressure leaching;and the catalytic mechanism was attributed to the redox couple Fe^3+/Fe^2+,where Fe3+oxidizes the H2S gas film and the reduced Fe2+state is subsequently oxidized by the dissolved oxygen.Furthermore,the effect of temperature,H2SO4 concentration,and oxygen partial pressure on the artificial sphalerite with different iron contents was studied.The sphalerite samples with iron content were observed to dissolve more easily in sulfuric acid compared to the non-iron samples.Moreover,the activation energy of artificial sphalerite was observed to be lower in the sample with 25.70%iron content(22.26 kJ/mol)compared to that with no iron(32.31 kJ/mol);and the apparent reaction orders were obtained with respect to H2SO4 concentration(1.10 and 1.36)and oxygen partial pressure(1.29 and 1.41),respectively.A comprehensive kinetic model was developed on the basis of the experimental data and the fitted leaching ratio plot;and the kinetic equations for the leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation were determined.
基金This work were supported by the National Natural Science Foundation of China(No.30170010,29973030)The Teaching and Research Award Program for Outstanding Young Professors in High Education Institute,MOE,China(2001).
文摘Through the method of initial heat release rate, the kinetic property of tyrosine oxidation catalyzed by tyrosinase from Pseudomonas maltophilia was investigated using a LKB-2107 batch microcalorimeter. Tyrosine was catalyzed and oxidized into L-dopa, then into melanin catalyzed by tyrosinase. We found that the tyrosinase reaction obeyed the Michaelis-Menten kinetics, and at 298.15K and pH 7.0, the initial exothermic rate (W0 ) are in the range of 0.1567~0.5704 mJ·s-1, the maximum exothermic rate (Wmax) are in 0.4152 ~ 0.8143mol·L-1, and mean value of the Michaelis constant (Km) is 2.199±0.105104 mol·L-1.
文摘A photoredox-catalyzed cascade carbon/carboxylation of activated alkenes with malonates acetals and CO_(2) has been achieved,leading to a range of functionalized 1,1,3-tricarboxylates in good efficiency under mild reaction conditions.This reaction provides a facile and sustainable method for the synthesis of tricarboxylates by using CO_(2) as the carboxylic source.
基金supported by Youth Innovation and Technology Project of high School in Shandong Province (No. 2019KJC021)Natural Science Foundation of Qinghai Province of China (No. 2020-ZJ-915)。
文摘A mild and efficient photochemical multi-component tandem reaction of quinoxalin-2(1H)-ones, alkenes and sulfinic acids is reported. This tandem reaction could be conveniently carried out at room temperature by employing 4Cz IPN as the metal-free photocatalyst and dioxygen(air) as the environmentally benign oxidant. A number of sulfonated quinoxalin-2(1H)-ones were obtained in satisfactory yields with favorable functional group tolerance. Radical trapping experiment and fluorescence quenching experiments were performed to elucidate this visible-light mediated radical reaction process.
文摘An efficient and practical route to various 3-alkoxylquinoxalin-2(1 H)-ones through visible-light photocatalytic C(sp^2)-H/O-H cross-dehydrogenation coupling of quinoxalin-2(1 H)-ones and alcohols,employing ambient air as an oxidant at room temperature under metal-free conditions,was developed.
基金Supported by the Project of International Cooperation between China and U kraine(No.0 4 3- 0 5 ) and the Project ofKJCXGC- 0 1Northwest Norm al U niversityChina
文摘A new analytical method is proposed for the determination of heroin based on a sequential perturbation caused by trace amounts of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction between hydrogen peroxide and sodium thiocyanate in an alkaline medium with the aid of a continuous-flow stirred tank reactor(CSTR). The method relies on the linear relationship between the change in oscillation period of the system and the concentration of heroin, with a detecting limit of 4.0×10^(-7) mol/L. The calibration curve fits a linear equation very well when the concentration of heroin is in the range of 2.0×10^(-6)_1.2×10^(-5) mol/L(r=0.9971). This method features good precision(RSD=0.98%). The influences of temperature, injection point, flow rate and reaction variables on the oscillation period were investigated in detail and a possible mechanism of the performance of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction system is also discussed. The proposed method opens a new avenue for the determination of heroin.
