A novel binary photosensitization system composed of benzophenone (BP)/diphenyliodonium chloride (DPIOC) Ariethylamine (TEA), exhibiting a good photoresponse at near UV and visible light regions, was used as the initi...A novel binary photosensitization system composed of benzophenone (BP)/diphenyliodonium chloride (DPIOC) Ariethylamine (TEA), exhibiting a good photoresponse at near UV and visible light regions, was used as the initiator for photopolymerization of MMA. The radical photogeneration in the binary system consists mainly of two parallel reactions, i. e. , BP/TEA photohydrogen-abstraction and DPIOC/TEA complex photodecomposition, but the latter is more active than the former. The results of comparative study indicate that the rate of polymerization induced by the binary system (BDT)is remarkably higher than those by the corresponding single systems The polymerization rates are proportional to [BP]^(0.16), [DPIOC]^(0.32) [TEA]^(0.45) and [MMA]. The mechanism is also discussed.展开更多
The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electro...The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electron donor, which results in extending the photosensitivity range of DPIOC/TEA system up to above 500nm compared with DPIOC alone. The kinetic studies on photopolymerization of methyl methacrylate (MMA) were carried out in CH_3CN: H_2O (14: 1, v/v) mixture solution at 30℃ by dilatometer. The results obtained show that the polymerization rate (R_p) increases with increasing concentrations of DPIOC and TEA with exponent 0. 65 and 0. 62 respectively. The activation energy E_a and k_p/k_^(1/2) value were determined to be 4.1 Kcal mol^(-1) and 0.045 respectively. The other influence factors and reaction mechanism were also discussed.展开更多
Task specific onium salt has been presented as soluble support in the synthesis of benzopyrans in this paper. This method allows for results by far superior to those reported other soluble supports and allows for very...Task specific onium salt has been presented as soluble support in the synthesis of benzopyrans in this paper. This method allows for results by far superior to those reported other soluble supports and allows for very easy purifications of reaction products.展开更多
The present paper contains the effects of the ammonium ion, counter ion, solvent and anion being transferred on the solid-liquid phase transfer equilibrium constant of quaternary ammonium salts. The most striking diff...The present paper contains the effects of the ammonium ion, counter ion, solvent and anion being transferred on the solid-liquid phase transfer equilibrium constant of quaternary ammonium salts. The most striking difference between solid-liquid and liquid-liquid phase transfer equilibriums is that the length of alkyl chain shows a large effect on the latter but little on the former This means that the chain length affects only the hydrophobicity, rather than the lipophilicity.Keywords Quaternary ammonium salt, Phase transfer catalysis, Equilibrium constant, Hydrophobicity, Lipophilicity展开更多
For over two decades,sulfate reduction with ammonium oxidation(SRAO)had been reported from laboratory experiments.SRAO was considered an autotrophic process mediated by anammox bacteria,in which ammonium as electron d...For over two decades,sulfate reduction with ammonium oxidation(SRAO)had been reported from laboratory experiments.SRAO was considered an autotrophic process mediated by anammox bacteria,in which ammonium as electron donor was oxidized by the electron acceptor sulfate.This process had been attributed to observed transformations of nitrogenous and sulfiirous compounds in natural environments.Results obtained differed largely for the conversion mole ratios(ammonium/sulfate),and even the intermediate and final products of sulfate reduction.Thus,the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible.In this study,continuous reactor experiments(with working volume of 3.8L)and batch tests were conducted under normal anaerobic(0.2<DO<0.5 mg/L)/strict anaerobic(DO<0.2 mg/L)conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion.Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition,while absent under strict anaerobic conditions for same anammox consortia.Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed.Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could,in fact,be a combination of aerobic ammonium oxidation,anammox and heterotrophic sulfate reduction processes.展开更多
In this work it was presented an application of task specific onium salt as soluble support for the synthesis of 3-amino-5-aryl-2,5- dihydropyridazines. This soluble support is of wide applicability and combines advan...In this work it was presented an application of task specific onium salt as soluble support for the synthesis of 3-amino-5-aryl-2,5- dihydropyridazines. This soluble support is of wide applicability and combines advantages of solid phase synthesis without its limitations with those of solution phase chemistry. After a simple washing step, products were cleaved from the supports and obtained in good yields.展开更多
Recently, visible light sensitive photoinitiation systems have been developing very quickly, owing to the rapid development of both laser and photocuring technologies.Of these systems intra-ion-pair electron transfer ...Recently, visible light sensitive photoinitiation systems have been developing very quickly, owing to the rapid development of both laser and photocuring technologies.Of these systems intra-ion-pair electron transfer dye photosensitization systems specially attract great attention. One of the reasons for this is that a large variety of available dyes can al-most cover the whole visible and near infrared spectrum range and thus can be chosen as the photosensitization component based on different requirements. On the other hand, the photosensitization and initiation components are placed together before irradiation by the coulombic attraction between the cations and anions, which overcomes the limitation of the diffusion process to ordinary bimolecular energy or electron transfer and thus展开更多
Ⅰ. INTRODUCTION The crystal and molecular structures of the series （η5-C5H5）2MCl2 and （η5RC5H4）2MCl2, where M=Ti, Zr, Hf, have been reported. Thachev and Prout et al. have determined the molecular structures of...Ⅰ. INTRODUCTION The crystal and molecular structures of the series （η5-C5H5）2MCl2 and （η5RC5H4）2MCl2, where M=Ti, Zr, Hf, have been reported. Thachev and Prout et al. have determined the molecular structures of the series （η5-C5H5）2MCl2, where M=Ti, Zr. Petersen and Cesarotti have determined the molecular structures展开更多
The gelatinous and macroporous phase transfer catalysts with multiple active centers were synthesized by means of quarterisation of PEG tertiary amine and chloromethylated St DVB copolymer. They were examined as phase...The gelatinous and macroporous phase transfer catalysts with multiple active centers were synthesized by means of quarterisation of PEG tertiary amine and chloromethylated St DVB copolymer. They were examined as phase transfer catalysts in the reaction of n C 8H 17 Br with solid NaI. The experimental results showed that the reaction rate was first order with respect to the concentration of n C 8H 17 Br. The effects of catalyst structure on the catalytic activity were also investigated. The observed reaction rate constant ( k obsd ) increased as the degree of cross linking of polymer decreased. Macroporous catalysts showed a higher activity (2～2 5 times) than that of microporous catalysts with the same degree of cross linking of polymer, particle size and amount of supported PEG. Molecular weight of PEG also showed much influence on k obsd . As molecular weight of PEG rose properly, the catalysts showed a higher activity. The results were discussed from the aspect of triphase catalysis reaction mechanism.展开更多
文摘A novel binary photosensitization system composed of benzophenone (BP)/diphenyliodonium chloride (DPIOC) Ariethylamine (TEA), exhibiting a good photoresponse at near UV and visible light regions, was used as the initiator for photopolymerization of MMA. The radical photogeneration in the binary system consists mainly of two parallel reactions, i. e. , BP/TEA photohydrogen-abstraction and DPIOC/TEA complex photodecomposition, but the latter is more active than the former. The results of comparative study indicate that the rate of polymerization induced by the binary system (BDT)is remarkably higher than those by the corresponding single systems The polymerization rates are proportional to [BP]^(0.16), [DPIOC]^(0.32) [TEA]^(0.45) and [MMA]. The mechanism is also discussed.
文摘The diphenyliodonium salt (DPIOC)/triethylamine (TEA) is used as photoinitiator for radical photopolymerization. It was found that a ground state CT complex formed between DPIOC as electron acceptor and TEA as electron donor, which results in extending the photosensitivity range of DPIOC/TEA system up to above 500nm compared with DPIOC alone. The kinetic studies on photopolymerization of methyl methacrylate (MMA) were carried out in CH_3CN: H_2O (14: 1, v/v) mixture solution at 30℃ by dilatometer. The results obtained show that the polymerization rate (R_p) increases with increasing concentrations of DPIOC and TEA with exponent 0. 65 and 0. 62 respectively. The activation energy E_a and k_p/k_^(1/2) value were determined to be 4.1 Kcal mol^(-1) and 0.045 respectively. The other influence factors and reaction mechanism were also discussed.
基金Supported by the National Natural Sciences Foundation of China(No.20772026)the 2007 Excellent Mid-youth Innovative Team Project of the Education Department of Hubei Province, China(No.T200701)
文摘Task specific onium salt has been presented as soluble support in the synthesis of benzopyrans in this paper. This method allows for results by far superior to those reported other soluble supports and allows for very easy purifications of reaction products.
文摘The present paper contains the effects of the ammonium ion, counter ion, solvent and anion being transferred on the solid-liquid phase transfer equilibrium constant of quaternary ammonium salts. The most striking difference between solid-liquid and liquid-liquid phase transfer equilibriums is that the length of alkyl chain shows a large effect on the latter but little on the former This means that the chain length affects only the hydrophobicity, rather than the lipophilicity.Keywords Quaternary ammonium salt, Phase transfer catalysis, Equilibrium constant, Hydrophobicity, Lipophilicity
基金This work was supported by the National Natural Science Foundation of China(Nos.51478284,21607110 and 51408387)the National&Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology,Suzhou University of Science and Technology(No.2018KF02).
文摘For over two decades,sulfate reduction with ammonium oxidation(SRAO)had been reported from laboratory experiments.SRAO was considered an autotrophic process mediated by anammox bacteria,in which ammonium as electron donor was oxidized by the electron acceptor sulfate.This process had been attributed to observed transformations of nitrogenous and sulfiirous compounds in natural environments.Results obtained differed largely for the conversion mole ratios(ammonium/sulfate),and even the intermediate and final products of sulfate reduction.Thus,the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible.In this study,continuous reactor experiments(with working volume of 3.8L)and batch tests were conducted under normal anaerobic(0.2<DO<0.5 mg/L)/strict anaerobic(DO<0.2 mg/L)conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion.Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition,while absent under strict anaerobic conditions for same anammox consortia.Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed.Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could,in fact,be a combination of aerobic ammonium oxidation,anammox and heterotrophic sulfate reduction processes.
基金the Natural Sciences Foundation of Hubei province in China(Nos.2007ABA031 and 2008CDA078)
文摘In this work it was presented an application of task specific onium salt as soluble support for the synthesis of 3-amino-5-aryl-2,5- dihydropyridazines. This soluble support is of wide applicability and combines advantages of solid phase synthesis without its limitations with those of solution phase chemistry. After a simple washing step, products were cleaved from the supports and obtained in good yields.
文摘Recently, visible light sensitive photoinitiation systems have been developing very quickly, owing to the rapid development of both laser and photocuring technologies.Of these systems intra-ion-pair electron transfer dye photosensitization systems specially attract great attention. One of the reasons for this is that a large variety of available dyes can al-most cover the whole visible and near infrared spectrum range and thus can be chosen as the photosensitization component based on different requirements. On the other hand, the photosensitization and initiation components are placed together before irradiation by the coulombic attraction between the cations and anions, which overcomes the limitation of the diffusion process to ordinary bimolecular energy or electron transfer and thus
文摘Ⅰ. INTRODUCTION The crystal and molecular structures of the series （η5-C5H5）2MCl2 and （η5RC5H4）2MCl2, where M=Ti, Zr, Hf, have been reported. Thachev and Prout et al. have determined the molecular structures of the series （η5-C5H5）2MCl2, where M=Ti, Zr. Petersen and Cesarotti have determined the molecular structures
文摘The gelatinous and macroporous phase transfer catalysts with multiple active centers were synthesized by means of quarterisation of PEG tertiary amine and chloromethylated St DVB copolymer. They were examined as phase transfer catalysts in the reaction of n C 8H 17 Br with solid NaI. The experimental results showed that the reaction rate was first order with respect to the concentration of n C 8H 17 Br. The effects of catalyst structure on the catalytic activity were also investigated. The observed reaction rate constant ( k obsd ) increased as the degree of cross linking of polymer decreased. Macroporous catalysts showed a higher activity (2～2 5 times) than that of microporous catalysts with the same degree of cross linking of polymer, particle size and amount of supported PEG. Molecular weight of PEG also showed much influence on k obsd . As molecular weight of PEG rose properly, the catalysts showed a higher activity. The results were discussed from the aspect of triphase catalysis reaction mechanism.
