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学者姓名：刘永东
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摘要 ：
Aliphatic amines as common constituents of dissolved organic nitrogen (DON) exhibit high reactivity during ozonation; however, our understanding of their degradation mechanisms is very limited. In this study, methylamine (MA) and ethylamine (EA), as well as their secondary and tertiary amines (DMA, DEA, TMA and TEA) were chosen as aliphatic amine models and their degradation mechanisms during ozonation were investigated by using the DFT method. The oxygen-transfer reaction occurs initially and rapidly in the ozonation of all the above amines with a ΔG≠ value of 8-10 kcal mol-1 in great agreement with the experimental rate constant of 104 to 107 M-1 s-1. Moreover, N-oxide as the main degradation product for tertiary amines directly forms after oxygen-transfer, while nitroalkanes as main products for secondary and primary amines are yielded after a series of reactions mediated by hydroxylamine and nitrosoalkane with a ΔG≠ value of 10-13 kcal mol-1. Regarding the minor N-dealkylated products for all amines, alkylamino alcohol is an important intermediate possibly generated via a radical reaction pathway with a ΔG≠ value of 21-34 kcal mol-1. Additionally, comparison of the reactivity of aliphatic amines, hydroxylamines and alkylamino alcohols with ozone was made and elucidated in this study. The results are expected to expand our understanding of the degradation mechanisms for nitrogenous compounds during ozonation.
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| GB/T 7714 | Shen Qunfang , Liu Yong Dong , Zhong Rugang . Degradation mechanisms of simple aliphatic amines under ozonation: a DFT study. [J]. | Environmental science. Processes & impacts , 2021 , 23 (3) : 480-490 . |
| MLA | Shen Qunfang 等. "Degradation mechanisms of simple aliphatic amines under ozonation: a DFT study." . | Environmental science. Processes & impacts 23 . 3 (2021) : 480-490 . |
| APA | Shen Qunfang , Liu Yong Dong , Zhong Rugang . Degradation mechanisms of simple aliphatic amines under ozonation: a DFT study. . | Environmental science. Processes & impacts , 2021 , 23 (3) , 480-490 . |
| 导入链接 | NoteExpress RIS BibTex |
摘要 ：
Chloropicrin as one of the most frequently detected N-DBPs has drawn great attention due to its high toxicity. However, our understanding of its formation mechanism is still very limited. A combined computational and experimental approach was used in this study to reveal chloropicrin formation mechanism during chlorination. Ethylamine, n-propylamine, alanine and tryptophan along with the above two amines and their four derivatives substituted by -OH or/and -NO2 groups were chosen as computational and experimental model precursors, respectively. The results indicate that primary amines and free amino acids are more likely to share the same chloropicrin formation pathway including N-chlorination, imidization, β-C-alcoholization, N-nitration, α-C-chlorination and dealdehydation processes. Moreover, elimination of hydrochloric acid from N,N-dichloro-amine and electrophilic addition of N-chloroalkylimide with hypochlorous acid were found to be the rate-limiting steps among all the elementary reactions. By skipping over both of the above rate-limiting steps, RCH(OH)CH2NO2 and RCH(OH)CH2NH(OH) compounds were proposed to be potent chloropicrin precursors, and experiments confirmed that 2-nitroethanol and N-methylhydroxylamine have the highest chloropicrin yields in the chlorination among all the precursors reported to date. The findings of this work are helpful for expanding the knowledge of chloropicrin formation mechanisms and predicting the potential chloropicrin precursors.
关键词 ：
Chlorination Chlorination Chloropicrin Chloropicrin DFT DFT Free amino acids Free amino acids Primary amines Primary amines
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| GB/T 7714 | Zhou Yingying , Ye Zhao-Xi , Huang Huang et al. Formation mechanism of chloropicrin from amines and free amino acids during chlorination: A combined computational and experimental study. [J]. | Journal of hazardous materials , 2021 , 416 : 125819 . |
| MLA | Zhou Yingying et al. "Formation mechanism of chloropicrin from amines and free amino acids during chlorination: A combined computational and experimental study." . | Journal of hazardous materials 416 (2021) : 125819 . |
| APA | Zhou Yingying , Ye Zhao-Xi , Huang Huang , Liu Yong Dong , Zhong Rugang . Formation mechanism of chloropicrin from amines and free amino acids during chlorination: A combined computational and experimental study. . | Journal of hazardous materials , 2021 , 416 , 125819 . |
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摘要 ：
Nitroaromatic compounds (NACs) in the environment can cause serious public health and environmental problems due to their potential toxicity. This study established quantitative structure-toxicity relationship (QSTR) models for the acute oral toxicity of NACs towards rats following the stringent OECD principles for QSTR modelling. All models were assessed by various internationally accepted validation metrics and the OECD criteria. The best QSTR model contains seven simple and interpretable 2D descriptors with defined physicochemical meaning. Mechanistic interpretation indicated that van der Waals surface area, presence of C-F at topological distance 6, heteroatom content and frequency of C-N at topological distance 9 are main factors responsible for the toxicity of NACs. This proposed model was successfully applied to a true external set (295 compounds), and prediction reliability was analysed and discussed. Moreover, the rat-mouse and mouse-rat interspecies quantitative toxicity-toxicity relationship (iQTTR) models were also constructed, validated and employed in toxicity prediction for true external sets consisting of 67 and 265 compounds, respectively. These models showed good external predictivity that can be used to rapidly predict the rat oral acute toxicity of new or untested NACs falling within the applicability domain of the models, thus being beneficial in environmental risk assessment and regulatory purposes.
关键词 ：
Acute oral toxicity Acute oral toxicity iQTTR iQTTR Mechanism of toxicity Mechanism of toxicity Nitroaromatic compounds Nitroaromatic compounds QSTR QSTR Risk assessment Risk assessment
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| GB/T 7714 | Hao, Yuxing , Sun, Guohui , Fan, Tengjiao et al. In vivo toxicity of nitroaromatic compounds to rats: QSTR modelling and interspecies toxicity relationship with mouse [J]. | JOURNAL OF HAZARDOUS MATERIALS , 2020 , 399 . |
| MLA | Hao, Yuxing et al. "In vivo toxicity of nitroaromatic compounds to rats: QSTR modelling and interspecies toxicity relationship with mouse" . | JOURNAL OF HAZARDOUS MATERIALS 399 (2020) . |
| APA | Hao, Yuxing , Sun, Guohui , Fan, Tengjiao , Tang, Xiaoyu , Zhang, Jing , Liu, Yongdong et al. In vivo toxicity of nitroaromatic compounds to rats: QSTR modelling and interspecies toxicity relationship with mouse . | JOURNAL OF HAZARDOUS MATERIALS , 2020 , 399 . |
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摘要 ：
N-Nitrosodimethylamine (NDMA) formation from tertiary amines during chloramination has aroused widespread concern due to its unusually high toxicity and the high NDMA conversion yields of some tertiary amines especially for ranitidine. However, the formation mechanisms have not been fully understood yet. In this study, density functional theory (DFT) calculation as a useful complementary approach to the experiments was used to reinvestigate NDMA formation pathways from tertiary amines during chloramination. The results indicate that the formation of NDMA includes five processes: nucleophilic substitution, aminyl radical generation, oxidation of radical by O-2,N-nitroso-compound cation formation and release of NDMA. In the first two processes, the tertiary amines are more likely to first react with dichloramine and the result of which then reacts with monochloramine to generate aminyl radicals. It is elucidated that dichloramine plays a pronounced role in NDMA formation. Moreover, the aminyl radical formation accompanied by the release of chlorine radicals predominates over that by the release of (NH2)-N-center dot radicals proposed in the literature mainly due to the lower homolytic bond dissociation energy of N-Cl relative to that of N-H. Importantly, the activation free energy of the release of NDMA from the N-nitroso-compound cation, which is fundamentally related to the previously reported heterolytic ONN(Me)(2)-R+ bond dissociation energy, was found to be a key indication for distinguishing potential NDMA precursors from tertiary amines. The findings of this work are helpful for expanding the knowledge of NDMA formation mechanisms and predicting potential NDMA precursors during disinfection.
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| GB/T 7714 | Zhang, Shuo , Zhou, Yingying , Liu, Yong Dong et al. Reinvestigation of NDMA formation mechanisms from tertiary amines during chloramination: a DFT study [J]. | ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY , 2020 , 6 (8) : 2078-2088 . |
| MLA | Zhang, Shuo et al. "Reinvestigation of NDMA formation mechanisms from tertiary amines during chloramination: a DFT study" . | ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY 6 . 8 (2020) : 2078-2088 . |
| APA | Zhang, Shuo , Zhou, Yingying , Liu, Yong Dong , Zhong, Rugang . Reinvestigation of NDMA formation mechanisms from tertiary amines during chloramination: a DFT study . | ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY , 2020 , 6 (8) , 2078-2088 . |
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摘要 ：
N-Chloro-alpha-amino acids formed in the chlorination disinfection treatment of water or wastewater and in living organisms have attracted extensive attention due to the potential toxicities of themselves and their decomposition products. The degradation mechanisms of three N-chloro-alpha-amino acids, i.e., N-chloro-glycine, N-chloro-alanine, and N-chloro-valine, have been systematically investigated using quantum chemical computations. The results indicate that N-chloro-alpha-amino acid anions undergo two competitive degradation pathways: a concerted Grob fragmentation (CGF) and beta-elimination (beta-E). Generally, the former predominates over the latter under neutral conditions and finally generates amines and carbonyls, while the latter is preferred under base-promoted conditions and mainly produces the respective alpha-keto acid anions or nitriles in the end. To gain deeper insights into the substitution effects, in view of the advantages of quantum chemical computations, a number of real or designed N-chloro-alpha-amino acids with traditional electron-donating groups (EDG) or electron-withdrawing groups (EWG) have been studied. All of the substituted N-chloro-alpha-amino acids, regardless of the type and position of substituents, are kinetically more favorable than N-monochloro-glycine for degradation via the CGF pathway. Moreover, conjugated EDG substituted on the N-terminal facilitate both CGF and beta-E reactions, whereas conjugated EDG and EWG on the alpha-carbon are only favorable for the CGF and beta-E reactions, respectively. These results are expected to expand our understanding of organic N-chloramine degradation mechanisms and chlorination reaction characteristics.
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| GB/T 7714 | Zhao, Huiyuan , Zhou, Yingying , Han, Chunxiu et al. Degradation Mechanisms and Substituent Effects of N-Chloro-alpha-Amino Acids: A Computational Study [J]. | ENVIRONMENTAL SCIENCE & TECHNOLOGY , 2020 , 54 (5) : 2635-2645 . |
| MLA | Zhao, Huiyuan et al. "Degradation Mechanisms and Substituent Effects of N-Chloro-alpha-Amino Acids: A Computational Study" . | ENVIRONMENTAL SCIENCE & TECHNOLOGY 54 . 5 (2020) : 2635-2645 . |
| APA | Zhao, Huiyuan , Zhou, Yingying , Han, Chunxiu , Liu, Yong Dong , Zhong, Rugang . Degradation Mechanisms and Substituent Effects of N-Chloro-alpha-Amino Acids: A Computational Study . | ENVIRONMENTAL SCIENCE & TECHNOLOGY , 2020 , 54 (5) , 2635-2645 . |
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摘要 ：
硝基多环芳烃(NACs)是一类重要的环境有机污染物。在本研究中，我们基于NACs对鼠伤寒沙门氏菌TA100菌株的突变性数据，建立了定量构效关系(QSAR)和分类模型。
关键词 ：
QSAR QSAR 分类研究 分类研究 硝基芳烃化合物 硝基芳烃化合物 突变性 突变性 风险评估 风险评估
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| GB/T 7714 | 郝雨婞 , 孙国辉 , 范腾蛟 et al. 硝基芳烃化合物致突变性的QSAR和分类研究 [C] //NCEC2019第十届全国环境化学大会论文集 . 2019 : 45-45 . |
| MLA | 郝雨婞 et al. "硝基芳烃化合物致突变性的QSAR和分类研究" NCEC2019第十届全国环境化学大会论文集 . (2019) : 45-45 . |
| APA | 郝雨婞 , 孙国辉 , 范腾蛟 , 刘永东 , 赵丽娇 , 钟儒刚 et al. 硝基芳烃化合物致突变性的QSAR和分类研究 NCEC2019第十届全国环境化学大会论文集 . (2019) : 45-45 . |
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摘要 ：
Chloropicrin (TCNM) as one of the most frequently detected nitrogenous disinfection byproducts (N-DBPs) has attracted extensive attention due to its high toxicity. Although much research work on TCNM has been done, its formation mechanism during chlorination has not been known clearly yet. In this study, TCNM formation mechanisms from methylamine (MA) during chlorination, including N-chlorination of MA by hypochlorous acid to generate dichloromethylamine (DCMA) first and then oxidation of DCMA to form nitromethane (NM) and chloronitromethane (CNM), and finally TCNM formation from C-chlorination of NM and CNM, were investigated by using the DFT method. The calculated results show that in N-chlorination of MA, 2-3 water molecules involved in the reaction facilitate Cl+ and proton transfer with the activation free energies (DGs) for the first and second chlorination in the range of 4-7 and 1417 kcal mol(-1), respectively, which are in good agreement with the experimental results. Formation of NM and CNM proceeds through a series of elimination, addition, and oxidation reactions with DGs of the rate-limiting steps being around 34-37 kcal mol(-1), and the subsequent C-chlorination of methyl in NM and CNM by hypochlorous acid is a rapid process with DGs below 7 kcal mol(-1). This infers that the TCNM formation mechanism from DCMA is more likely to undergo first N-oxidation and then Cchlorination. These results can explain the experimental findings that the molar yield of TCNM from MA during chlorination is low (< 0.1%) whereas that from NM is rather high (similar to 45%). This work will be helpful to elucidate formation mechanisms of all the halonitromethanes during chlorination.
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| GB/T 7714 | Han, Chunxiu , Zhao, Huiyuan , Dong, Meng et al. The formation mechanism of chloropicrin from methylamine during chlorination: a DFT study [J]. | ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS , 2019 , 21 (4) : 761-770 . |
| MLA | Han, Chunxiu et al. "The formation mechanism of chloropicrin from methylamine during chlorination: a DFT study" . | ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS 21 . 4 (2019) : 761-770 . |
| APA | Han, Chunxiu , Zhao, Huiyuan , Dong, Meng , Liu, Yong Dong , Zhong, Rugang . The formation mechanism of chloropicrin from methylamine during chlorination: a DFT study . | ENVIRONMENTAL SCIENCE-PROCESSES & IMPACTS , 2019 , 21 (4) , 761-770 . |
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摘要 ：
N-nitrosodimethylamine (NDMA) as the most frequently detected disinfection by-product has aroused widespread concern due to its unusually high carcinogenicity, however, there is still limited understanding of its formation mechanisms. In this study, the formation mechanisms of NDMA from some typical hydrazines and hydrazones with high NDMA conversion yields (60% similar to 90%) during ozonation, i.e., unsymmetrical dimethylhydrazine (UDMH), 1-formyl-2,2-dimethylhydrazine (FDMH), formaldehyde dimethylhydrazone (FDH) and acetone dimethylhydrazone (ADMH), were investigated by using DFT method with the M05 functional. A new NDMA formation mechanism from hydrazines during ozonation was proposed, in which the initial step is hydrogen abstraction rather than previously reported oxygen addition. For hydrazones, the C atom of the-N = C moiety in hydrazones is preferred to be attacked by ozone to generate N,N-dimethylaminonitrene (DMAN), which is an important intermediate in NDMA formation during ozonation. Moreover, the reactivity order of the following H atoms in hydrogen/hydride ion abstraction (HA) by ozone is -NH2 >-N(CH3)(2) >-CO-NH similar to = C(CH3)(2) > = CH-. Additionally, formation pathways of some experimentally detected compounds, i.e., HOOOH, HOOH and HCOH, in the ozonation of hydrazine were elucidated in this study. The results are expected to expand our understanding of NDMA formation mechanisms and ozone reaction characteristics.
关键词 ：
DFT DFT Hydrazines Hydrazines Hydrazones Hydrazones NDMA NDMA Ozonation Ozonation
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| GB/T 7714 | Dong, Meng , Liu, Yong Dong , Zhong, Rugang . NDMA formation mechanisms from typical hydrazines and hydrazones during ozonation: A computational study [J]. | JOURNAL OF HAZARDOUS MATERIALS , 2019 , 366 : 370-377 . |
| MLA | Dong, Meng et al. "NDMA formation mechanisms from typical hydrazines and hydrazones during ozonation: A computational study" . | JOURNAL OF HAZARDOUS MATERIALS 366 (2019) : 370-377 . |
| APA | Dong, Meng , Liu, Yong Dong , Zhong, Rugang . NDMA formation mechanisms from typical hydrazines and hydrazones during ozonation: A computational study . | JOURNAL OF HAZARDOUS MATERIALS , 2019 , 366 , 370-377 . |
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摘要 ：
Nitroaromatic compounds (NACs) are an important type of environmental organic pollutants. However, it is lack of sufficient information relating to their potential adverse effects on human health and the environment due to the limited resources. Thus, using in silico technologies to assess their potential hazardous effects is urgent and promising. In this study, quantitative structure activity relationship (QSAR) and classification models were constructed using a set of NACs based on their mutagenicity against Salmonella typhimurium TA100 strain. For QSAR studies, DRAGON descriptors together with quantum chemistry descriptors were calculated for characterizing the detailed molecular information. Based on genetic algorithm (GA) and multiple linear regression (MLR) analyses, we screened descriptors and developed QSAR models. For classification studies, seven machine learning methods along with six molecular fingerprints were applied to develop qualitative classification models. The goodness of fitting, reliability, robustness and predictive performance of all developed models were measured by rigorous statistical validation criteria, then the best QSAR and classification models were chosen. Moreover, the QSAR models with quantum chemistry descriptors were compared to that without quantum chemistry descriptors and previously reported models. Notably, we also obtained some specific molecular properties or privileged substructures responsible for the high mutagenicity of NACs. Overall, the developed QSAR and classification models can be utilized as potential tools for rapidly predicting the mutagenicity of new or untested NACs for environmental hazard assessment and regulatory purposes, and may provide insights into the in vivo toxicity mechanisms of NACs and related compounds.
关键词 ：
Classification Classification Hazard assessment Hazard assessment Mutagenicity Mutagenicity Nitroaromatic compounds Nitroaromatic compounds QSAR QSAR Toxicity mechanism Toxicity mechanism
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| GB/T 7714 | Hao, Yuxing , Sun, Guohui , Fan, Tengjiao et al. Prediction on the mutagenicity of nitroaromatic compounds using quantum chemistry descriptors based QSAR and machine learning derived classification methods [J]. | ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY , 2019 , 186 . |
| MLA | Hao, Yuxing et al. "Prediction on the mutagenicity of nitroaromatic compounds using quantum chemistry descriptors based QSAR and machine learning derived classification methods" . | ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 186 (2019) . |
| APA | Hao, Yuxing , Sun, Guohui , Fan, Tengjiao , Sun, Xiaodong , Liu, Yongdong , Zhang, Na et al. Prediction on the mutagenicity of nitroaromatic compounds using quantum chemistry descriptors based QSAR and machine learning derived classification methods . | ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY , 2019 , 186 . |
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摘要 ：
针对原子结构中原子能级的教学进行探索和研究,在加强学生对原子能级概念理解和掌握的基础上,扩展性引入其在X-射线光电子能谱中应用的简单实例,以期帮助学生突破原子结构中原子能级知识的难点。
关键词 ：
原子能级 原子能级 X-射线光电子能谱 X-射线光电子能谱 原子结构 原子结构 普通化学 普通化学
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| GB/T 7714 | 刘永东 , 张淑芬 , 钟儒刚 . 普通化学教学中原子能级知识的扩展应用研究 [J]. | 中国教育技术装备 , 2018 , (23) : 77-79 . |
| MLA | 刘永东 et al. "普通化学教学中原子能级知识的扩展应用研究" . | 中国教育技术装备 23 (2018) : 77-79 . |
| APA | 刘永东 , 张淑芬 , 钟儒刚 . 普通化学教学中原子能级知识的扩展应用研究 . | 中国教育技术装备 , 2018 , (23) , 77-79 . |
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