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学者姓名：刘永东
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摘要 ：
Iodinated aromatic disinfection byproducts have attracted much attention owing to their high toxicity. However, little has been known about the iodination mechanism to date. In this study, the iodination of model aromatic precursors, tyrosine (Tyr) and its model dipeptides, by HOI and other iodinating agents was explored using a quantum chemical computational method, and the halogenation of Tyr by HOX (X = Cl, Br, and I) was compared. The results indicate that the phenolate salt plays a key role in the iodination of the phenol ring in Tyr compounds by HOI via the classic SEAr mechanism and the second deprotonation becomes the rate-limiting step, which explains why the kinetic isotope effect (KIE) was observed in the iodination of aromatic compounds. Among the seven possible iodinating agents present in chloramination, HOI is the predominant one, and I2 is the second in the iodination of the phenol ring under typical chloramination conditions. In the further investigation of bromination and chlorination, the KIE was found to also occur in the bromination of Tyr. More importantly, the different reactivity orders of HOX reacting with the phenol ring and the amino group in Tyr are related to the hardness of both HOX and substrates, which can be evaluated from the energy gap (ELUMO-HOMO) between the LUMO and HOMO energies. Following the "like-attracts-like" principle, the halogenating agent prefers the substrate with a similar ELUMO-HOMO value. The results are helpful in further understanding the iodination mechanism and identifying various halogenated products. The iodination mechanism of Tyr compounds by HOI and other iodinating agents was studied using the DFT method, and the halogenation of Tyr by HOX (X = Cl, Br, and I) was compared.
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| GB/T 7714 | Qiu, Yue , Liu, Yong Dong , Zhong, Rugang . New insights into the iodination mechanism of tyrosine and its dipeptides and comparison with chlorination and bromination reactions [J]. | ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY , 2024 , 10 (6) : 1421-1431 . |
| MLA | Qiu, Yue 等. "New insights into the iodination mechanism of tyrosine and its dipeptides and comparison with chlorination and bromination reactions" . | ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY 10 . 6 (2024) : 1421-1431 . |
| APA | Qiu, Yue , Liu, Yong Dong , Zhong, Rugang . New insights into the iodination mechanism of tyrosine and its dipeptides and comparison with chlorination and bromination reactions . | ENVIRONMENTAL SCIENCE-WATER RESEARCH & TECHNOLOGY , 2024 , 10 (6) , 1421-1431 . |
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摘要 ：
As an alternative disinfectant to free chlorine, monochloramine reduces the formation of regulated disinfection byproducts (DBPs); however, it also contributes to the formation of highly toxic nitrogenous DBPs (N-DBPs), especially through the aldehyde pathway. The current understanding of aldehyde pathway mechanisms is limited. In this study, the transformation pathways of acetaldehyde and its substituted aldehydes into the corresponding nitriles and (N-chloro)amides during chloramination were investigated using quantum chemical calculations. Consistent with previous studies, 1-chloroamino alcohol first forms in the chloramination of aldehydes and then undergoes competitive dehydration and HCl elimination branch reactions to generate the nitrile and (N-chloro)amide, respectively. Iminol was found to be a key intermediate for (N-chloro)amide formation. Moreover, the results indicated that acetaldehydes substituted with electron-donating groups (EDGs) and electron-withdrawing groups (EWGs) are beneficial to the formation of the respective nitriles and N-chloro-amides, while those substituted with conjugated groups (CGs) are favourable for both. Based upon the above results, in addition to acetaldehyde, other aldehydes, such as propionaldehyde, glycolaldehyde, 3-butenal, and phenylacetaldehyde, which are the alpha-H of acetaldehydes substituted with -CH3, -OH, -CH =CH2, and -C6H5 groups, respectively, are potential precursors of toxic nitriles and (N-chloro) amides during chloramination. Thus, more attention should be given to these aldehydes. The findings of this work are helpful for further understanding the aldehyde pathway mechanisms and predicting potential precursors of toxic nitriles and (N-chloro)amides during chloramination.
关键词 ：
Aldehyde pathway Aldehyde pathway Disinfection byproducts Disinfection byproducts Quantum chemical calculation Quantum chemical calculation Substituted effects Substituted effects
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| GB/T 7714 | Xue, Jianying , Zhou, Yingying , Liu, Yong Dong et al. Transformation mechanisms of acetaldehyde and its substituted aldehydes into the corresponding nitriles and (N-chloro)amides during chloramination: A computational study [J]. | SCIENCE OF THE TOTAL ENVIRONMENT , 2022 , 836 . |
| MLA | Xue, Jianying et al. "Transformation mechanisms of acetaldehyde and its substituted aldehydes into the corresponding nitriles and (N-chloro)amides during chloramination: A computational study" . | SCIENCE OF THE TOTAL ENVIRONMENT 836 (2022) . |
| APA | Xue, Jianying , Zhou, Yingying , Liu, Yong Dong , Zhong, Rugang . Transformation mechanisms of acetaldehyde and its substituted aldehydes into the corresponding nitriles and (N-chloro)amides during chloramination: A computational study . | SCIENCE OF THE TOTAL ENVIRONMENT , 2022 , 836 . |
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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 Delta G(not equal) value of 8-10 kcal mol(-1) in great agreement with the experimental rate constant of 10(4) to 10(7) 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 Delta G(not equal) 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 Delta G(not equal) 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 et al. "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 . |
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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, beta-C-alcoholization, N-nitration, alpha-Cchlorination 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 ：
DFT DFT Chloropicrin Chloropicrin Chlorination Chlorination 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 . |
| 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) . |
| 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 . |
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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 ：
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 ：
Mechanism of toxicity Mechanism of toxicity Risk assessment Risk assessment QSTR QSTR Acute oral toxicity Acute oral toxicity iQTTR iQTTR Nitroaromatic compounds Nitroaromatic compounds
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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 ：
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 ：
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 QSAR QSAR Nitroaromatic compounds Nitroaromatic compounds 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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