The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
J. Chovelon - One of the best experts on this subject based on the ideXlab platform.
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sulfate radical based oxidation of the aminopyralid and picloram herbicides the role of amino group on Pyridine Ring
Journal of Hazardous Materials, 2021Co-Authors: Xuerui Yang, Xue Cao, Li Zhang, Lei Zhou, Guangli Xiu, Corinne Ferronato, J. ChovelonAbstract:Abstract The widespread utilization of pesticides has attracted increasing attention to their environmental impacts and effective removal strategies. In the present study, the degradation of herbicides picloram (PCLO) and aminopyralid (AMP) with similar structures were investigated systematically by thermo activated persulfate. Overweight SO4•− was determined to be the predominant oxidizing species by quenching experiment. Obtained by laser-flash photolysis (LFP), reaction rate constants of SO4•− towards AMP and PCLO were determined at 1.56 × 109 M−1s−1 and 1.21 × 109 M−1s−1, respectively. Product analysis revealed that both substances underwent similar oxidation paths, namely, successive oxidation on Pyridine Ring and formation of coupling-products as well as further hydroxylation and decarboxylation. Amino group on the Pyridine Ring was identified as the main reactive site, which was further confirmed by DFT calculation. It was susceptible attacked by SO4•− to form deamination, nitration, and self-coupling products. These couples could be further oxidatively dehydrated to form azo and a series of azo derivatives. EOCSAR program predicted significant hazards on aquatic species duRing the formation of these couplings and azo derivatives. Our work emphasized the potential ability and toxicity of contaminates to produce azo substances in the presence of amino groups on the Pyridine Ring.
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New insights into clopyralid degradation by sulfate radical: Pyridine Ring cleavage pathways.
Water Research, 2020Co-Authors: X. Yang, X. Ding, X. Wang, C. Ferronato, J. Chovelon, Huan-huan Fan, G. XiuAbstract:Abstract Contamination by herbicides such as clopyralid (CLP) poses a significant threat to human health and ecological systems. In the present study, efficient removal of CLP was achieved by thermo activated persulfate, among which sulfate radical was identified as the predominant oxidizing species responsible for the decontamination. Based on high resolution LC-MS, derivatization method and density functional theory (DFT) computation, the detailed oxidation pathways and mechanisms were proposed. The primary oxidation pathways included dechlorination-hydroxylation, decarboxylation and the formation of quinone-like moieties. Afterwards, numerous intermediate byproducts ranging from high molecular to very small ones were identified, suggesting the Pyridine Ring was damaged duRing the thermo activated persulfate process. The detected products containing six and five carbons indicated the Pyridine Ring cleavage would take place on the quinone-structure intermediate. Further oxidation could continue by breaking each bond on the Ring-cleavage product, yielding a series of short-chain carbonyl chemicals, carboxylic acids and inorganic ions. In addition, the presence of dissolved oxygen (DO) was favorable to CLP degradation, indicating DO played an important role in applying such technology. The degradation rate constants of CLP increased appreciably with increasing temperature, and acidic pH facilitated the CLP degradation. The results obtained in this work would increase our understanding on the environmental fates of nitrogen heterocyclic compounds duRing sulfate radical (SO4•−)-based advanced oxidation processes (SR-AOPs).
G. Xiu - One of the best experts on this subject based on the ideXlab platform.
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New insights into clopyralid degradation by sulfate radical: Pyridine Ring cleavage pathways.
Water Research, 2020Co-Authors: X. Yang, X. Ding, X. Wang, C. Ferronato, J. Chovelon, Huan-huan Fan, G. XiuAbstract:Abstract Contamination by herbicides such as clopyralid (CLP) poses a significant threat to human health and ecological systems. In the present study, efficient removal of CLP was achieved by thermo activated persulfate, among which sulfate radical was identified as the predominant oxidizing species responsible for the decontamination. Based on high resolution LC-MS, derivatization method and density functional theory (DFT) computation, the detailed oxidation pathways and mechanisms were proposed. The primary oxidation pathways included dechlorination-hydroxylation, decarboxylation and the formation of quinone-like moieties. Afterwards, numerous intermediate byproducts ranging from high molecular to very small ones were identified, suggesting the Pyridine Ring was damaged duRing the thermo activated persulfate process. The detected products containing six and five carbons indicated the Pyridine Ring cleavage would take place on the quinone-structure intermediate. Further oxidation could continue by breaking each bond on the Ring-cleavage product, yielding a series of short-chain carbonyl chemicals, carboxylic acids and inorganic ions. In addition, the presence of dissolved oxygen (DO) was favorable to CLP degradation, indicating DO played an important role in applying such technology. The degradation rate constants of CLP increased appreciably with increasing temperature, and acidic pH facilitated the CLP degradation. The results obtained in this work would increase our understanding on the environmental fates of nitrogen heterocyclic compounds duRing sulfate radical (SO4•−)-based advanced oxidation processes (SR-AOPs).
Songyuan Dai - One of the best experts on this subject based on the ideXlab platform.
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zinc porphyrins with a Pyridine Ring anchoRing group for dye sensitized solar cells
Chemistry-an Asian Journal, 2013Co-Authors: Kun Cao, Jin Cui, Yibo Zhang, Yan Shen, Jun Zhu, Songyuan Dai, Wei Chen, Yibing Cheng, Mingkui WangAbstract:AnchoRing groups are extremely important in controlling the performance of dye-sensitized solar cells (DSCs). The design and characterization of sensitizers with new anchoRing groups, in particular non-carboxylic acid groups, has become a recent focus of DSC research. Herein, new donor-π-acceptor zinc-porphyrin dyes with a Pyridine Ring as an anchoRing group have been designed and synthesized for applications in DSCs. Photophysical and electrochemical investigations demonstrated that the Pyridine Ring worked effectively as an anchoRing group for the porphyrin sensitizers. DSCs that were based on these new porphyrins showed an overall power-conversion efficiency of about 4.0 % under full sunlight (AM 1.5G, 100 mW cm(-2)).
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Zinc Porphyrins with a Pyridine‐Ring‐AnchoRing Group for Dye‐Sensitized Solar Cells
Chemistry an Asian journal, 2013Co-Authors: Kun Cao, Jin Cui, Yibo Zhang, Yan Shen, Jun Zhu, Songyuan DaiAbstract:AnchoRing groups are extremely important in controlling the performance of dye-sensitized solar cells (DSCs). The design and characterization of sensitizers with new anchoRing groups, in particular non-carboxylic acid groups, has become a recent focus of DSC research. Herein, new donor-π-acceptor zinc-porphyrin dyes with a Pyridine Ring as an anchoRing group have been designed and synthesized for applications in DSCs. Photophysical and electrochemical investigations demonstrated that the Pyridine Ring worked effectively as an anchoRing group for the porphyrin sensitizers. DSCs that were based on these new porphyrins showed an overall power-conversion efficiency of about 4.0 % under full sunlight (AM 1.5G, 100 mW cm(-2)).
Kun Cao - One of the best experts on this subject based on the ideXlab platform.
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Organic Sensitizers with Pyridine Ring AnchoRing Group for p-Type Dye-Sensitized Solar Cells
The Journal of Physical Chemistry C, 2014Co-Authors: Jin Cui, Kun Cao, Yan Shen, Zhong Wang, Getachew Alemu, Huailiang Yuang, Yibing ChengAbstract:Recently, p-type dye-sensitized solar cells (p-DSSCs) have attracted increasing attention. The widely used carboxylic acid groups for TiO2 based sensitizers may not be the optimal choice for p-DSSCs. Herein new donor-π-acceptor organic sensitizers with Pyridine Ring as anchoRing group are designed and synthesized for p-DSSCs. The detailed investigation demonstrates that carboxylic acid groups may have an effect on the negative shift of the valence band edge of NiO induced by surface protonation, which lowers the hole-injection process and the device photovoltage, while the Pyridine Ring works effectively without this problem. The p-DSSC based on the new sensitizer shows an overall conversion efficiency of ∼0.16% under full sunlight (AM 1.5G, 100 mW cm–2) irradiation.
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Investigation of the regeneration kinetics of organic dyes with Pyridine Ring anchoRing groups by scanning electrochemical microscopy
RSC Adv., 2014Co-Authors: Getachew Alemu, Kun Cao, Jin Cui, Yan Shen, Mingkui WangAbstract:This work reports on a study of regeneration kinetics of organic dyes with Pyridine Ring group sensitized NiO electrodes in combination with iodide-based and organic thiolate-based electrolytes by scanning electrochemical microscopy (SCEM) with a feedback model. These dyes have showed promising performance in p-type dye-sensitized solar cells. The investigation reveals that the anchoRing group affects the effective rate constant, showing an efficient dye-regeneration process for the dye with carboxylic acid anchoRing groups. Meanwhile, it is worth noting that the regeneration process between the reduced dye and the oxidized state of the thiolate-based electrolyte is much faster than that of the iodide-based electrolyte.
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zinc porphyrins with a Pyridine Ring anchoRing group for dye sensitized solar cells
Chemistry-an Asian Journal, 2013Co-Authors: Kun Cao, Jin Cui, Yibo Zhang, Yan Shen, Jun Zhu, Songyuan Dai, Wei Chen, Yibing Cheng, Mingkui WangAbstract:AnchoRing groups are extremely important in controlling the performance of dye-sensitized solar cells (DSCs). The design and characterization of sensitizers with new anchoRing groups, in particular non-carboxylic acid groups, has become a recent focus of DSC research. Herein, new donor-π-acceptor zinc-porphyrin dyes with a Pyridine Ring as an anchoRing group have been designed and synthesized for applications in DSCs. Photophysical and electrochemical investigations demonstrated that the Pyridine Ring worked effectively as an anchoRing group for the porphyrin sensitizers. DSCs that were based on these new porphyrins showed an overall power-conversion efficiency of about 4.0 % under full sunlight (AM 1.5G, 100 mW cm(-2)).
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Zinc Porphyrins with a Pyridine‐Ring‐AnchoRing Group for Dye‐Sensitized Solar Cells
Chemistry an Asian journal, 2013Co-Authors: Kun Cao, Jin Cui, Yibo Zhang, Yan Shen, Jun Zhu, Songyuan DaiAbstract:AnchoRing groups are extremely important in controlling the performance of dye-sensitized solar cells (DSCs). The design and characterization of sensitizers with new anchoRing groups, in particular non-carboxylic acid groups, has become a recent focus of DSC research. Herein, new donor-π-acceptor zinc-porphyrin dyes with a Pyridine Ring as an anchoRing group have been designed and synthesized for applications in DSCs. Photophysical and electrochemical investigations demonstrated that the Pyridine Ring worked effectively as an anchoRing group for the porphyrin sensitizers. DSCs that were based on these new porphyrins showed an overall power-conversion efficiency of about 4.0 % under full sunlight (AM 1.5G, 100 mW cm(-2)).
Shinzo Kagabu - One of the best experts on this subject based on the ideXlab platform.
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effect of substituents at the 5 position of the Pyridine Ring of imidacloprid on insecticidal activity against periplaneta americana
Pest Management Science, 2007Co-Authors: Shinzo Kagabu, Yuko Murase, Rie Imai, Nakako Ito, Keiichiro NishimuraAbstract:The insecticidal activities of imidacloprid derivatives with a wide range of substituents at the 5-position on the Pyridine Ring against American cockroaches, Periplaneta americana (L.), were measured by injection with and without synergists propyl 2-propynyl phenylphosphonate and piperonyl butoxide. The log(1/MLD) value (MLD = minimal lethal dose in mol) without synergists was 7.96 for the methyl derivative, and the values were lower for other derivatives. Synergists enhanced the potencies of all the compounds tested. ConsideRing these compounds and those with other substituents at this position, the region for maximum activity was predicted to be in the conjunction of the pyridyl 6-chlorine atom with a lipophilic small group in the 5-position.
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methyl trifluoromethyl and methoxycarbonyl introduction to the fifth position on the Pyridine Ring of chloronicotinyl insecticide imidacloprid
Synthetic Communications, 2006Co-Authors: Shinzo KagabuAbstract:Abstract Imidacloprid is the first chloronicotinyl insecticide and is currently the largest‐selling insecticide worldwide. As a project to find its variants of different insecticidal spectra, derivatives substituted with methyl, trifluoromethyl, and methoxycarbonyl at the fifth position on the Pyridine Ring of imidacloprid were prepared.
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Methyl, Trifluoromethyl, and Methoxycarbonyl—Introduction to the Fifth Position on the Pyridine Ring of Chloronicotinyl Insecticide Imidacloprid
Synthetic Communications, 2006Co-Authors: Shinzo KagabuAbstract:Abstract Imidacloprid is the first chloronicotinyl insecticide and is currently the largest‐selling insecticide worldwide. As a project to find its variants of different insecticidal spectra, derivatives substituted with methyl, trifluoromethyl, and methoxycarbonyl at the fifth position on the Pyridine Ring of imidacloprid were prepared.
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Insecticidal activity of imidacloprid derivatives with an alkoxy group at the C5 position of the Pyridine Ring
Journal of Pesticide Science, 2006Co-Authors: Shinzo Kagabu, Yuya Fujii, Keiichiro NishimuraAbstract:Six derivatives of imidacloprid with an alkoxy group introduced at the fifth position on the Pyridine Ring were prepared. Minimal lethal doses in mol (MLDs) were determined in American cockroaches both with and without synergists, piperonyl butoxide and propargyl propyl benzenephosphonate. The log(1/MLD) value without synergists was 7.43 for the methoxy substituted derivative. Values for the higher alkyloxy homologues particularly the n-propoxy derivative were lower. Synergists combined enhanced the potency by about one log unit for each compound. The introduction of any alkoxy group does not improve the activity of imidacloprid. © Pesticide Science Society of Japan
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Quantitative structure–activity relationships of imidacloprid and its analogs with substituents at the C5 position on the Pyridine Ring in the neuroblocking activity
Journal of Pesticide Science, 2006Co-Authors: Keiichiro Nishimura, Kazuhisa Kiriyama, Shinzo KagabuAbstract:Two nerve activities of imidacloprid analogs with various substituents at the 5-position of the Pyridine Ring were measured: the conduction blockage in the excised central nerve cord of the American cockroach, and the binding inhibition of a radioligand, [3H]imidacloprid, to the membrane preparation of housefly-head homogenates. Neuroblocking activity was quantitatively analyzed using physicochemical substituent parameters. The greater the electron-releasing resonance effect, the higher the activity. The introduction of sizable and alkoxy substituents was unfavorable. The nerve-binding activity of the tested compounds was linearly related to the neuroblocking activity with one exception. The higher the binding activity, the higher the blocking activity. © Pesticide Science Society of Japan
