This review will focus on the recent advances of radical and photo reactions and their applications in the natural products total synthesis. A brief introduction to the development and mechanism of the newly developed...This review will focus on the recent advances of radical and photo reactions and their applications in the natural products total synthesis. A brief introduction to the development and mechanism of the newly developed radical and photo reactions will be presented. The organization of the each section is based on the type of reactions used. Examples of synthetic applications are discussed to demonstrate the potential of related methodologies and inspire future explorations.展开更多
Diphenyl-2, 2-dicyanoethylene reacts with 10-methyl-9, 10-dihydroacridine in deaerated acetonitrile under irradiation with l>320 nm to give the coupling product 1, 1-diphenyl-1-(10-methyl-9-acridinyl)-2, 2-dicyanoe...Diphenyl-2, 2-dicyanoethylene reacts with 10-methyl-9, 10-dihydroacridine in deaerated acetonitrile under irradiation with l>320 nm to give the coupling product 1, 1-diphenyl-1-(10-methyl-9-acridinyl)-2, 2-dicyanoethane, which has been characterized by X-ray crystallographic, MS and NMR analyses.展开更多
Experimental data are presented to test and validate a kinetic model for the oxidation of 2 chlorophenol wastewater by photo assisted Fenton process. The data showed that this process had produced good effects under a...Experimental data are presented to test and validate a kinetic model for the oxidation of 2 chlorophenol wastewater by photo assisted Fenton process. The data showed that this process had produced good effects under acidic conductions. Up to 90% 2 chlorophenol was removed after 90 minute reaction time with H 2O 2 of 25% COD Cr, in , while in UV/H 2O 2 system only 16 8% 2 chlorophenol was removed after one hour treatment. The optimal pH in this reaction occurred between pH 3 0 and pH 4.0. The reaction kinetics for photo assisted Fenton process experimented in this research was investigated. Kinetic models were proposed for the treatment of 2 chlorophenol wastewater. The reaction was found to follow the 2nd order. The equations of reaction kinetics are as follows:-d[RH]d t = K RH [RH][H 2O 2] 0exp (-K H 2O 2 t );-d[COD Cr ]d t = K COD Cr [COD Cr ][H 2O 2] 0exp(-K′ t ). The prediction of the models was found to be in a good agreement with experimental results, thus confirming the proposed reaction mechanism.展开更多
CIDNP techniques were applied to study the mechanism of photocycloadditions of 2-chloro-5-methoxybenzoquinone 1 with arylacetylenes 2-5 in benzene-d6 and acetonitrile-d6 respectively.
The roles of reaction inhomogeneity in phase separation of polymer mixtures were described and summarized via two examples:photocross-link of polymer mixtures in the bulk state and photopolymerization of monomer in th...The roles of reaction inhomogeneity in phase separation of polymer mixtures were described and summarized via two examples:photocross-link of polymer mixtures in the bulk state and photopolymerization of monomer in the liquid state. The reaction kinetics,the reaction-induced elastic strain and the phase separation kinetics were monitored respectively by UV-Vis spectroscopy,Mach-Zehnder interferometry and laser-scanning confocal microscopy.It was found that phase separation in the bulk state was strongly inf...展开更多
Systematical experiments were done at five temperature levels: （500 ℃,） （630 ℃,） （900 ℃,） （1 000 ℃） and （1 100 ℃） to illuminate the layer structure of the multi-layered metal-intermetallic composites of...Systematical experiments were done at five temperature levels: （500 ℃,） （630 ℃,） （900 ℃,） （1 000 ℃） and （1 100 ℃） to illuminate the layer structure of the multi-layered metal-intermetallic composites of Ni-Al system that were fabricated by a previously reported simple and cost-effective method. The analysis of back scattering photos and XRD examination of specimens reveal that the look like single compound layer is composed of several different components. The primary phase produced during reaction is Ni2Al3 and there exists a like two-phase field between NiAl3 and Ni2Al3. The high temperature phases like NiAl and Ni3Al are also found at low temperature. The results indicate that the key driving force of in-situ reaction is not temperature, but the atom concentration.展开更多
Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange w...Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange was selected as degradation target for photocatalytic experiments. The photocatalytic activities were investigated by visible spectro- photometer. Photocatalytic kinetics parameters were studied by the Langmuir-Hinshelwood model and Arrhenius formula. It was observed that the sea urchin-like morphology dramatically improved the photocatalytic activity of cuprous oxide. The photo-degradation belongs to the first-order reaction and the maximum degradation rate could reach 94.37%. The activation energy and pre-exponential factor are 41.18 KJ·mol-1 and 1.07 × 106, respectively. After seven times recycling, the sample still showed high photo-catalytic efficiency and stability.展开更多
By using first-principles simulations based on time-dependent density functional theory, the chemical reaction of an HCl molecule encapsulated in C60 induced by femtosecond laser pulses is observed. The H atom starts ...By using first-principles simulations based on time-dependent density functional theory, the chemical reaction of an HCl molecule encapsulated in C60 induced by femtosecond laser pulses is observed. The H atom starts to leave the Cl atom and is reflected by the C60 wall. The coherent nuclear dynamic behaviors of bond breakage and recombination of the HCl molecule occurring in both polarized parallel and perpendicular to the H-Cl bond axis are investigated. The radial oscillation is also found in the two polarization directions of the laser pulse. The relaxation time of the H-Cl bond lengths in transverse polarization is slow in comparison with that in longitudinal polarization. Those results are important for studying the dynamics of the chemical bond at an atomic level.展开更多
A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination ...A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination technology. Characterizations with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed that, in addition to anatase type TiO2, a new active phase (Ti, Sn)O2 (with particle size of 2.0-4.3 nm) formed, and there were no SnO2 crystals observed in the range of the doping concentration studied. Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts. Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method, Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity. The photo-catalytic degradation rate of phenol could reach as high as 93.5% after 7 h. The preparation conditions of the new phase (Ti, Sn)O2 were investigated and its catalytic mechanism was proposed. The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size, large surface area and high activity.展开更多
基金supported by the National Natural Science Foundation of China (21272076, 21422203)the National Young TopNotch Talent Support Program+2 种基金the Qi Ming Xing Foundation of Shanghai Ministry of Science and Technology (14QA1401400)the program for professor of special appointment (Eastern Scholar) at Shanghai institutions of higher learningProgram for Changjiang Scholars and Innovative Research Team in University (PCSIRT)
文摘This review will focus on the recent advances of radical and photo reactions and their applications in the natural products total synthesis. A brief introduction to the development and mechanism of the newly developed radical and photo reactions will be presented. The organization of the each section is based on the type of reactions used. Examples of synthetic applications are discussed to demonstrate the potential of related methodologies and inspire future explorations.
文摘Diphenyl-2, 2-dicyanoethylene reacts with 10-methyl-9, 10-dihydroacridine in deaerated acetonitrile under irradiation with l>320 nm to give the coupling product 1, 1-diphenyl-1-(10-methyl-9-acridinyl)-2, 2-dicyanoethane, which has been characterized by X-ray crystallographic, MS and NMR analyses.
文摘Experimental data are presented to test and validate a kinetic model for the oxidation of 2 chlorophenol wastewater by photo assisted Fenton process. The data showed that this process had produced good effects under acidic conductions. Up to 90% 2 chlorophenol was removed after 90 minute reaction time with H 2O 2 of 25% COD Cr, in , while in UV/H 2O 2 system only 16 8% 2 chlorophenol was removed after one hour treatment. The optimal pH in this reaction occurred between pH 3 0 and pH 4.0. The reaction kinetics for photo assisted Fenton process experimented in this research was investigated. Kinetic models were proposed for the treatment of 2 chlorophenol wastewater. The reaction was found to follow the 2nd order. The equations of reaction kinetics are as follows:-d[RH]d t = K RH [RH][H 2O 2] 0exp (-K H 2O 2 t );-d[COD Cr ]d t = K COD Cr [COD Cr ][H 2O 2] 0exp(-K′ t ). The prediction of the models was found to be in a good agreement with experimental results, thus confirming the proposed reaction mechanism.
基金Financial support from the National Natural Science Foundation of China (No: 29975002) is gratefully acknowledged.
文摘CIDNP techniques were applied to study the mechanism of photocycloadditions of 2-chloro-5-methoxybenzoquinone 1 with arylacetylenes 2-5 in benzene-d6 and acetonitrile-d6 respectively.
基金supported by the Ministry of Education (MONKASHO),Japan through the Grant-in-Aid on the Priority-Research-Area"Molecular Nanodynamics"and"Soft Matter Physics".The Grant-in-Aid for Scientific Research (No.20350107) is also gratefully acknowledged.
文摘The roles of reaction inhomogeneity in phase separation of polymer mixtures were described and summarized via two examples:photocross-link of polymer mixtures in the bulk state and photopolymerization of monomer in the liquid state. The reaction kinetics,the reaction-induced elastic strain and the phase separation kinetics were monitored respectively by UV-Vis spectroscopy,Mach-Zehnder interferometry and laser-scanning confocal microscopy.It was found that phase separation in the bulk state was strongly inf...
文摘Systematical experiments were done at five temperature levels: （500 ℃,） （630 ℃,） （900 ℃,） （1 000 ℃） and （1 100 ℃） to illuminate the layer structure of the multi-layered metal-intermetallic composites of Ni-Al system that were fabricated by a previously reported simple and cost-effective method. The analysis of back scattering photos and XRD examination of specimens reveal that the look like single compound layer is composed of several different components. The primary phase produced during reaction is Ni2Al3 and there exists a like two-phase field between NiAl3 and Ni2Al3. The high temperature phases like NiAl and Ni3Al are also found at low temperature. The results indicate that the key driving force of in-situ reaction is not temperature, but the atom concentration.
文摘Sea urchin-like cuprous oxide with hollow glass microsphere as core was prepared using sodium sulfite as the reducing agent and sodium acetate-acetic acid as buffer solution in copper sulfate solution. Methyl orange was selected as degradation target for photocatalytic experiments. The photocatalytic activities were investigated by visible spectro- photometer. Photocatalytic kinetics parameters were studied by the Langmuir-Hinshelwood model and Arrhenius formula. It was observed that the sea urchin-like morphology dramatically improved the photocatalytic activity of cuprous oxide. The photo-degradation belongs to the first-order reaction and the maximum degradation rate could reach 94.37%. The activation energy and pre-exponential factor are 41.18 KJ·mol-1 and 1.07 × 106, respectively. After seven times recycling, the sample still showed high photo-catalytic efficiency and stability.
基金Project supported by the National Natural Science Foundation of China （Grant Nos. 11074176 and 10976019） and the Doctoral Program of Higher Education of China （Grant No. 20100181110080）.
文摘By using first-principles simulations based on time-dependent density functional theory, the chemical reaction of an HCl molecule encapsulated in C60 induced by femtosecond laser pulses is observed. The H atom starts to leave the Cl atom and is reflected by the C60 wall. The coherent nuclear dynamic behaviors of bond breakage and recombination of the HCl molecule occurring in both polarized parallel and perpendicular to the H-Cl bond axis are investigated. The radial oscillation is also found in the two polarization directions of the laser pulse. The relaxation time of the H-Cl bond lengths in transverse polarization is slow in comparison with that in longitudinal polarization. Those results are important for studying the dynamics of the chemical bond at an atomic level.
基金The authors thank the National Natural Scir nce Foun-dation of China(No.20076004)the National Development Project of High Technology(No.2001AA322030)the Doctoral Program of Higher Education(No.2000001005)for the financial support of this project.
文摘A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%-30.1%) were prepared from TiCI4 and SnCl4·5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination technology. Characterizations with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed that, in addition to anatase type TiO2, a new active phase (Ti, Sn)O2 (with particle size of 2.0-4.3 nm) formed, and there were no SnO2 crystals observed in the range of the doping concentration studied. Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts. Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method, Ti-Sn nano-composite photo-catalyst thus obtained showed significant improvement in catalytic activity. The photo-catalytic degradation rate of phenol could reach as high as 93.5% after 7 h. The preparation conditions of the new phase (Ti, Sn)O2 were investigated and its catalytic mechanism was proposed. The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size, large surface area and high activity.
