The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Chenzhong Bai - One of the best experts on this subject based on the ideXlab platform.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2',4,4'-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41×10-1 and 2.71×10-2 min-1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed. Baeyer–Villiger oxidation was a key mechanism for chloroform formation from pollutants containing aromatic ketone moieties during Chlorination disinfection.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2′,4,4′-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41 × 10−1 and 2.71 × 10−2 min−1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed.
Dongbin Wei - One of the best experts on this subject based on the ideXlab platform.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2',4,4'-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41×10-1 and 2.71×10-2 min-1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed. Baeyer–Villiger oxidation was a key mechanism for chloroform formation from pollutants containing aromatic ketone moieties during Chlorination disinfection.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2′,4,4′-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41 × 10−1 and 2.71 × 10−2 min−1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed.
-
formation of novel disinfection by products chlorinated benzoquinone phenyl benzoquinones and polycyclic aromatic hydrocarbons during Chlorination treatment on uv filter 2 4 dihydroxybenzophenone in swimming pool water
Journal of Hazardous Materials, 2019Co-Authors: Xuefeng Sun, Dongbin Wei, Wei Liu, Jialin Geng, Jun LiuAbstract:2,4-Dihydroxybenzophenone (BP-1) is an important component and metabolite of benzophenone-type (BPs) UV filters, it is widely used in commercial products and frequently detected in environmental media and organism samples. The transformation characteristics and genotoxicity changes of BP-1 during Chlorination disinfection process were explored. Nineteen transformation products were separated and tentatively identified, eleven of which were not previously reported. Most importantly, nine novel by-products including one chlorobenzoquinone, four phenyl benzoquinones, and four polycyclic aromatic hydrocarbons were formed during BP-1 Chlorination. Plausible transformation pathways for BP-1 during Chlorination treatment were proposed, in which Chlorination substitution, Baeyer-Villiger oxidation, hydrolysis, and CC coupling reactions were involved. The CC coupling reaction is firstly observed in Chlorination disinfection system. Higher pH values and chlorine doses would be a benefit for BP-1 transformation. The genotoxicity of the reaction mixture increased significantly with increasing chlorine dose under acid and neutral conditions due to the formation of benzoquinones and polycyclic aromatic hydrocarbons. It was noted that BP-1 and its chlorinated products were found in swimming pool water samples. This work inferred that BP-1 and its analogs are transformed during the Chlorination disinfection process and may cause potential ecological and health risks.
-
transformation of cefazolin during Chlorination process products mechanism and genotoxicity assessment
Journal of Hazardous Materials, 2013Co-Authors: Dongbin Wei, Guohua WeiAbstract:Large quantities of cephalosporins have entered into aquatic environment in recent years, posing potential adverse effect to human health and ecological safety. In this study, cefazolin, one of widely used cephalosporins, was targeted to explore its transformation behaviors in Chlorination disinfection process. With the help of ultra high performance liquid chromatography and high resolution mass spectroscopy, one chlorinated product and four oxidation products were detected in cefazolin Chlorination system. The corresponding transformation pathways of cefazolin were proposed. Two kinds of reactions occurred in Chlorination system, one was oxidation of thioether-sulfur to sulfoxide and di-sulfoxide, and the other was base-catalyzed electrophilic substitution of alpha-H of amide by chlorine atom. The pH value determined the occurrence of reaction types, and increasing chlorine dose promoted transformation of cefazolin. More importantly, genotoxicity in SOS/umu assay had an elevation after Chlorination, which might be attributed to the formation of chlorinated product and sulfoxide during Chlorination process.
Xuefeng Sun - One of the best experts on this subject based on the ideXlab platform.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2′,4,4′-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41 × 10−1 and 2.71 × 10−2 min−1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2',4,4'-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41×10-1 and 2.71×10-2 min-1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed. Baeyer–Villiger oxidation was a key mechanism for chloroform formation from pollutants containing aromatic ketone moieties during Chlorination disinfection.
-
formation of novel disinfection by products chlorinated benzoquinone phenyl benzoquinones and polycyclic aromatic hydrocarbons during Chlorination treatment on uv filter 2 4 dihydroxybenzophenone in swimming pool water
Journal of Hazardous Materials, 2019Co-Authors: Xuefeng Sun, Dongbin Wei, Wei Liu, Jialin Geng, Jun LiuAbstract:2,4-Dihydroxybenzophenone (BP-1) is an important component and metabolite of benzophenone-type (BPs) UV filters, it is widely used in commercial products and frequently detected in environmental media and organism samples. The transformation characteristics and genotoxicity changes of BP-1 during Chlorination disinfection process were explored. Nineteen transformation products were separated and tentatively identified, eleven of which were not previously reported. Most importantly, nine novel by-products including one chlorobenzoquinone, four phenyl benzoquinones, and four polycyclic aromatic hydrocarbons were formed during BP-1 Chlorination. Plausible transformation pathways for BP-1 during Chlorination treatment were proposed, in which Chlorination substitution, Baeyer-Villiger oxidation, hydrolysis, and CC coupling reactions were involved. The CC coupling reaction is firstly observed in Chlorination disinfection system. Higher pH values and chlorine doses would be a benefit for BP-1 transformation. The genotoxicity of the reaction mixture increased significantly with increasing chlorine dose under acid and neutral conditions due to the formation of benzoquinones and polycyclic aromatic hydrocarbons. It was noted that BP-1 and its chlorinated products were found in swimming pool water samples. This work inferred that BP-1 and its analogs are transformed during the Chlorination disinfection process and may cause potential ecological and health risks.
Xinyi Zhang - One of the best experts on this subject based on the ideXlab platform.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2',4,4'-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41×10-1 and 2.71×10-2 min-1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed. Baeyer–Villiger oxidation was a key mechanism for chloroform formation from pollutants containing aromatic ketone moieties during Chlorination disinfection.
-
free available chlorine initiated baeyer villiger oxidation a key mechanism for chloroform formation during aqueous Chlorination of benzophenone uv filters
Environmental Pollution, 2021Co-Authors: Xinyi Zhang, Dongbin Wei, Xuefeng Sun, Chenzhong BaiAbstract:Abstract Chloroform, a regulated disinfection by-product in water, is often generated during Chlorination disinfection treatment. However, the formation of chloroform is heavily dependent on the molecular structures of precursors. Moreover, compounds containing ketone moiety are ubiquitous in water environments. However, it is unclear if they can generate chloroform during Chlorination. In this study, 14 benzophenones (BPs), efficient and widely used UV filters, with different substituents were selected to explore chloroform formation during Chlorination. All 14 BPs generated chloroform, with yields dependent on their molecular structures and operational conditions. Compounds 2,2′,4,4′-tetrahydroxy-BP and benzophenone produced the highest and lowest chloroform of 0.313 and 0.013 g/g, respectively, corresponding to the fastest and slowest formation rate constants of 1.41 × 10−1 and 2.71 × 10−2 min−1. Alkaline conditions and high chlorine dosages were favorable to chloroform formation. Three reactions played key roles in chloroform formation from BPs: (1) chlorine initiated Baeyer–Villiger oxidation converted ketone moieties of BP molecules into esters; (2) the esters further underwent hydrolysis and formed phenolic and benzoic products; and (3) benzoic acids underwent decarboxylation and hydrolysis to form phenolic products. Subsequently, these phenolic products could further generate chloroform in the Chlorination system. More importantly, BPs could generate chloroform in the ambient water matrices during practical Chlorination treatment. This work emphasized the critical role of Baeyer–Villiger oxidation for chloroform formation, implying that pollutants containing aromatic ketone moieties generate chloroform during Chlorination disinfection, and their potential risk should therefore be reviewed.
Michael J Davies - One of the best experts on this subject based on the ideXlab platform.
-
Chlorination and oxidation of the extracellular matrix protein laminin and basement membrane extracts by hypochlorous acid and myeloperoxidase
Redox biology, 2019Co-Authors: Tina Nybo, Simon Dieterich, Luke F Gamon, Christine Y Chuang, Astrid Hammer, Gerald Hoefler, Ernst Malle, Adelina Rogowskawrzesinska, Michael J DaviesAbstract:Abstract Basement membranes are specialized extracellular matrices that underlie arterial wall endothelial cells, with laminin being a key structural and biologically-active component. Hypochlorous acid (HOCl), a potent oxidizing and chlorinating agent, is formed in vivo at sites of inflammation via the enzymatic action of myeloperoxidase (MPO), released by activated leukocytes. Considerable data supports a role for MPO-derived oxidants in cardiovascular disease and particularly atherosclerosis. These effects may be mediated via extracellular matrix damage to which MPO binds. Herein we detect and quantify sites of oxidation and Chlorination on isolated laminin-111, and laminin in basement membrane extracts (BME), by use of mass spectrometry. Increased modification was detected with increasing oxidant exposure. Mass mapping indicated selectivity in the sites and extent of damage; Met residues were most heavily modified. Fewer modifications were detected with BME, possibly due to the shielding effects. HOCl oxidised 30 (of 56 total) Met and 7 (of 24) Trp residues, and chlorinated 33 (of 99) Tyr residues; 3 Tyr were dichlorinated. An additional 8 Met and 10 Trp oxidations, 14 Chlorinations, and 18 diChlorinations were detected with the MPO/H2O2/Cl- system when compared to reagent HOCl. Interestingly, Chlorination was detected at Tyr2415 in the integrin-binding region; this may decrease cellular adhesion. Co-localization of MPO-damaged epitopes and laminin was detected in human atherosclerotic lesions. These data indicate that laminin is extensively modified by MPO-derived oxidants, with structural and functional changes. These modifications, and compromised cell-matrix interactions, may promote endothelial cell dysfunction, weaken the structure of atherosclerotic lesions, and enhance lesion rupture.
-
Chlorination and oxidation of the extracellular matrix protein laminin and basement membrane extracts by hypochlorous acid and myeloperoxidase
Elsevier, 2019Co-Authors: Tina Nybo, Simon Dieterich, Luke F Gamon, Christine Y Chuang, Astrid Hammer, Gerald Hoefler, Ernst Malle, Adelina Rogowska-wrzesinska, Michael J DaviesAbstract:Basement membranes are specialized extracellular matrices that underlie arterial wall endothelial cells, with laminin being a key structural and biologically-active component. Hypochlorous acid (HOCl), a potent oxidizing and chlorinating agent, is formed in vivo at sites of inflammation via the enzymatic action of myeloperoxidase (MPO), released by activated leukocytes. Considerable data supports a role for MPO-derived oxidants in cardiovascular disease and particularly atherosclerosis. These effects may be mediated via extracellular matrix damage to which MPO binds. Herein we detect and quantify sites of oxidation and Chlorination on isolated laminin-111, and laminin in basement membrane extracts (BME), by use of mass spectrometry. Increased modification was detected with increasing oxidant exposure. Mass mapping indicated selectivity in the sites and extent of damage; Met residues were most heavily modified. Fewer modifications were detected with BME, possibly due to the shielding effects. HOCl oxidised 30 (of 56 total) Met and 7 (of 24) Trp residues, and chlorinated 33 (of 99) Tyr residues; 3 Tyr were dichlorinated. An additional 8 Met and 10 Trp oxidations, 14 Chlorinations, and 18 diChlorinations were detected with the MPO/H2O2/Cl- system when compared to reagent HOCl. Interestingly, Chlorination was detected at Tyr2415 in the integrin-binding region; this may decrease cellular adhesion. Co-localization of MPO-damaged epitopes and laminin was detected in human atherosclerotic lesions. These data indicate that laminin is extensively modified by MPO-derived oxidants, with structural and functional changes. These modifications, and compromised cell-matrix interactions, may promote endothelial cell dysfunction, weaken the structure of atherosclerotic lesions, and enhance lesion rupture. Keywords: Extracellular matrix, Hypochlorous acid, Laminin, Protein oxidation, 3-chlorotyrosine, Myeloperoxidas
