Time-resolved IR absorption spectroscopy has been used to atudy the photochemistry of W(CO)_6 in cyclohexane, carbon tetrachloride, and the mixture of carbon tetrachloride and cyelohexane. The reastion of photolytical...Time-resolved IR absorption spectroscopy has been used to atudy the photochemistry of W(CO)_6 in cyclohexane, carbon tetrachloride, and the mixture of carbon tetrachloride and cyelohexane. The reastion of photolytically generated W(CO)_5. C_6H_(12) with CCl_4 was investigated. An intermediate with a lifetime of about 0.5ms, presumably attributed as W(GO)_5.CCl_4, was first observed.展开更多
Photoinduced electron transfer (PET) processes between C 60-C 6H 8SO and Tetrathiafulvalene (TTF) have been studied by nanosecond laser photolysis. Quantum yields (Φ et) and rate constants of electron transfe...Photoinduced electron transfer (PET) processes between C 60-C 6H 8SO and Tetrathiafulvalene (TTF) have been studied by nanosecond laser photolysis. Quantum yields (Φ et) and rate constants of electron transfer (k et) from TTF to excited triplet state of fullerene-containing cyclic sulphoxide in benzonitrile (BN) have been evaluated by observing the transient absorption bands in the NIR region. With the decay of excited triplet state of fullerene-containing cyclic sulphoxide, the rise of radical anion of fullerene-containing cyclic sulphoxide is observed.展开更多
The degradation characteristic of 4-bromdiphenyl ether (BDE-4) was investigated in different solutions.The study indicates that the process of direct degradation of this compound is dependent upon the bromine and th...The degradation characteristic of 4-bromdiphenyl ether (BDE-4) was investigated in different solutions.The study indicates that the process of direct degradation of this compound is dependent upon the bromine and the ether bond connected to diphenyl by electron beam.laser flash photolysis was employed to determine the degradation of each species (cationic,neutral,and anionic).From these data,intermediate products of BDE-4 degradation were shown for direct irradiationdegradation.The neutral radical was formed during the photolysis of these compounds.For all the compounds,diphenyl ether and hydroxybiphenyl were observed as common products.Reaction of the BDE-4 under electron beam was debromide.The debromide rate of BDE-4 at pH=5.5 is somewhat lower than that of BDE-4 at pH=10.0.The decomposition rate for BDE-4 is 99.8% at pH=10.0 on the dose of 14 kGy.BDE-4 from its radical could provide bromine ion into water and the cation radical of BDE-4 formed quickly recombine with hydrogen radical and formed phenyl ether.展开更多
The reactions between chlorinated benzenes (CBzs) and hydrated electron (eaq^-) were investigated by the electron beam (EB) and laser flash photolysis (LFP) experiments. Under the EB irradiation, the effects o...The reactions between chlorinated benzenes (CBzs) and hydrated electron (eaq^-) were investigated by the electron beam (EB) and laser flash photolysis (LFP) experiments. Under the EB irradiation, the effects of irradiation dose, initial concentration and the number of Cl atoms on the removal efficiencies were further examined. At 10 kGy, the removal efficiencies of mono-CB, 1,3-diCB, 1,2-diCB and 1,4-diCB were 41.2%, 87.2%, 84.0%, and 84.1%, respectively. While irradiation dose was 50 kGy, the removal efficiencies increased to 47.4%, 95.8%, 95.0%, and 95.2%, respectively. Irradiation of CBzs solutions has shown that the higher the initial concentration, the lower the percentage of CBzs removal. In addition to this, the dechlorination efficiencies of 1,2-dichlorobenzene (1,2-diCB), 1,3-dichlorobenzene (1,3-diCB) and 1,4-dichlorobenzene (1,4-diCB) were much higher than that of chlorobenzene (mono-CB). The kinetics of the reactions was achieved with nanosecond LFP. The rate constants of second-order reaction between eaq^- with mono-CB, 1,2-diCB, 1,3-diCB and 1,4-diCB were (5.3±0.4) × 10^8, (4.76±0.1) × 10^9, (1.01±0.1) × 1010 and (3.29±0.2) × 10^9 L·mol^-1·s^-1, respectively. Density functional theory (DFT) calculations were performed to determine the optical properties of unstable CBzs anion radicals, and the main absorption peaks lied in the range of 300–550 nm. The primary reaction pathway of CBzs with eaq^- was gradual dechlorination, and the major products were Cl^- and benzene (CBzs(-Cl^-)). Furthermore, biphenyl (or chlorobiphenyl) was observed during the LFP, which was probably formed by recombination of benzene radicals.展开更多
文摘Time-resolved IR absorption spectroscopy has been used to atudy the photochemistry of W(CO)_6 in cyclohexane, carbon tetrachloride, and the mixture of carbon tetrachloride and cyelohexane. The reastion of photolytically generated W(CO)_5. C_6H_(12) with CCl_4 was investigated. An intermediate with a lifetime of about 0.5ms, presumably attributed as W(GO)_5.CCl_4, was first observed.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 0 0 710 12 ) ,ResearchFundfortheYoungTeacherPro gramofHigherEducationofChina (No .2 0 0 0 6 5 )andtheNaturalScienceFoundationofGuangdongProvince (No .0 0 0 70 0 )
文摘Photoinduced electron transfer (PET) processes between C 60-C 6H 8SO and Tetrathiafulvalene (TTF) have been studied by nanosecond laser photolysis. Quantum yields (Φ et) and rate constants of electron transfer (k et) from TTF to excited triplet state of fullerene-containing cyclic sulphoxide in benzonitrile (BN) have been evaluated by observing the transient absorption bands in the NIR region. With the decay of excited triplet state of fullerene-containing cyclic sulphoxide, the rise of radical anion of fullerene-containing cyclic sulphoxide is observed.
基金supported by the National Natural Science Foundation of China (Grant Nos.40830744,40973072)the National Key Technology Research and Development Program in the 11th Five Year Plan of China (Grant Nos. 2008BAC32B03,2009BAA24B04)the Shanghai leading Academic Discipline Project (Grant No.S30109)
文摘The degradation characteristic of 4-bromdiphenyl ether (BDE-4) was investigated in different solutions.The study indicates that the process of direct degradation of this compound is dependent upon the bromine and the ether bond connected to diphenyl by electron beam.laser flash photolysis was employed to determine the degradation of each species (cationic,neutral,and anionic).From these data,intermediate products of BDE-4 degradation were shown for direct irradiationdegradation.The neutral radical was formed during the photolysis of these compounds.For all the compounds,diphenyl ether and hydroxybiphenyl were observed as common products.Reaction of the BDE-4 under electron beam was debromide.The debromide rate of BDE-4 at pH=5.5 is somewhat lower than that of BDE-4 at pH=10.0.The decomposition rate for BDE-4 is 99.8% at pH=10.0 on the dose of 14 kGy.BDE-4 from its radical could provide bromine ion into water and the cation radical of BDE-4 formed quickly recombine with hydrogen radical and formed phenyl ether.
文摘The reactions between chlorinated benzenes (CBzs) and hydrated electron (eaq^-) were investigated by the electron beam (EB) and laser flash photolysis (LFP) experiments. Under the EB irradiation, the effects of irradiation dose, initial concentration and the number of Cl atoms on the removal efficiencies were further examined. At 10 kGy, the removal efficiencies of mono-CB, 1,3-diCB, 1,2-diCB and 1,4-diCB were 41.2%, 87.2%, 84.0%, and 84.1%, respectively. While irradiation dose was 50 kGy, the removal efficiencies increased to 47.4%, 95.8%, 95.0%, and 95.2%, respectively. Irradiation of CBzs solutions has shown that the higher the initial concentration, the lower the percentage of CBzs removal. In addition to this, the dechlorination efficiencies of 1,2-dichlorobenzene (1,2-diCB), 1,3-dichlorobenzene (1,3-diCB) and 1,4-dichlorobenzene (1,4-diCB) were much higher than that of chlorobenzene (mono-CB). The kinetics of the reactions was achieved with nanosecond LFP. The rate constants of second-order reaction between eaq^- with mono-CB, 1,2-diCB, 1,3-diCB and 1,4-diCB were (5.3±0.4) × 10^8, (4.76±0.1) × 10^9, (1.01±0.1) × 1010 and (3.29±0.2) × 10^9 L·mol^-1·s^-1, respectively. Density functional theory (DFT) calculations were performed to determine the optical properties of unstable CBzs anion radicals, and the main absorption peaks lied in the range of 300–550 nm. The primary reaction pathway of CBzs with eaq^- was gradual dechlorination, and the major products were Cl^- and benzene (CBzs(-Cl^-)). Furthermore, biphenyl (or chlorobiphenyl) was observed during the LFP, which was probably formed by recombination of benzene radicals.