SYNTHETIC COMMUNICATIONS
·
2018
·
IF 1.377
Xinyuan Ma,Qiong Mo,Jie Chang,Kai Xie
This paper mainly studied Pd-catalyzed regioselective chlorination of disubstituted 1,2,3-triazoles directed by the 1,2,3-triazole ring. A series of regioselective chlorinated products were synthesized in 47–86% yields using Pd(OAc)2 as a catalyst and CuCl2 as a chlorinated reagent. This method provides a new mean for the synthesis of 1,2,3-triazole halides which combines the formation of C-X bond with C-H activation.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2017
·
IF 4.784
Jun-wei Wang,Hong-xia Zhou,Cui-zhen Zhang,Wen-ning Liu,Bai-yao Zhao
As a thermal energy storage medium (TESM) at moderate-high temperature of concentrating solar power (CSP), the molten NaCl-MgCl 2 has sharp corrosive action on a metal container. The influence of MgCl 2 content on a metal corrosion behavior is not clear. The corrosion behavior of a Fe based alloy (GH1140) in molten NaCl-MgCl 2 (at 1123 K) with different content of MgCl 2 (wt%：0.0，48.9，61.0，93.6) were studied by the submergence corrosion experience. Results show that: after corrosion for 5 h, there is a negative correlation between the weight loss of samples and the content of MgCl 2 . In the molten salt without MgCl 2 , the sample was corroded according to the mechanism of “dissolution as anode- oxidizing- peeling off of oxide film”. After adding a little MgCl 2 in the molten salt , an unprotected MgO shell was formed on the sample surface. The samples weight decreased and obeyed a line law. The elements of Fe and Cr deplete in the corrosion layer. Corrosion mechanism is “dissolution as anode- oxidizing- reduction- chlorination”. When the content of MgCl 2 is very high in the molten salt, partial pressure of Cl 2 increases. The corrosion mechanism is similar to what in the molten salt with a little MgCl 2 , but the chlorination reaction is more severe.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Wenrui Xiang,Ruijuan Qu,Xinghao Wang,Zunyao Wang,May Bin-Jumah,Ahmed A. Allam,Feng Zhu,Zongli Huo
Phenolic endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA), 4-chlorophenol (4-CP) and nonylphenol (NP) are the most commonly detected pollutants in natural environments. The transformation of mixtures of the three phenolic pollutants during chlorination process was studied for the first time in this work. Single phenol can be effectively removed by free chlorine via electrophilic substitution and electron transfer reactions, with the generation of chlorinated phenols and self-coupling products. In mixture solution, the apparent second-order rate constants ( k app ) of 4-CP, BPA and NP at pH 8.0 was increased by 8.6%, 25% and 16%, respectively, as compared to the degradation of single-compound. According to the products identification and density functional theory calculations, the cross-coupling process can occur more easily than the self-coupling reaction, which might accelerate the removal of phenolic mixtures. In addition, humic acid (HA) exerts some inhibitory effect on the degradation of phenolic compounds, due to the competition for chlorine consumption and the reduction of phenoxy radicals to parent phenols. These findings shed light on the environmental fate of phenolic mixtures during aqueous chlorination process, which provide new information for the application of chlorination in water and wastewater treatment.
研究领域:
环境科学
·
水处理工程
·
化学动力学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2017
·
IF 4.208
Cong Li,Feilong Dong,John C. Crittenden,Feng Luo,Xinbo Chen,Taotao Zhao
The kinetics and mechanisms of 17β-estradiol (E2) chlorination in water distribution systems (WDS) were studied. We examined the impacts of different factors, including pH, temperature, humic acid concentration and type, and flow velocity. The experimental results showed that the rate constants in beaker tests and WDS were described by a pseudo-first-order model. pH had the greatest impact on E2 chlorination in the beaker tests. However, temperature had the greatest impact on E2 chlorination in WDS. Mechanistic analysis of E2 chlorination showed that chlorine attacked E2 in three stages: 1) halogenation of the aromatic ring, 2) cleavage of the benzene moiety and chlorine or bromine substitution formation, and 3) formation of trihalomethanes (THMs) and halogenated acetic acids (HAAs) from phenolic intermediates through benzene ring opening with chlorine and/or bromine substitution of hydrogen on the carbon atoms. In the third stage, the concentrations of THMs and HAAs increased rapidly.
研究领域:
环境科学
·
生物学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Xiaoting Gao,Xianshi Wang,Youwei Jiang,Dezhen Kong,Xiangrui Pan,Jun Ma,Yanan Liu
Halogenated benzoquinones (HBQs) are frequently detected in tap water . HBQ levels are correlated with water age. As the water–transmission distance (water age) increases, the levels of bromo-benzoquinones (Br-BQs) decreased and those of chloro-benzoquinones (Cl-BQs) remained relatively stable in drinking water–distribution system in the presence of residual chlorine. 2,3,5,6-Tetrachloro-1,4-benzoquinone (TCBQ) and 2,6-dibromo-1,4-benzoquinone (DBBQ) were the most abundant Cl-BQ and Br-BQ, with maximum concentrations of 60.2 and 181.4 ng/L, respectively. TCBQ and DBBQ were chosen as representatives of HBQs to investigate their reactions with chlorine, including kinetics, pathways, and changes in toxicity. The hydrolysis and chlorination rates of HBQs were significantly pH-dependent, and the kinetic rates of DBBQ were faster than TCBQ in the pH range of 5–10. Chlorination converted highly toxic TCBQ and DBBQ to less-toxic chlorinated/brominated aliphatic disinfection by-products (DBPs), thereby reducing the overall toxicity of water bodies. This study provides comprehensive insights into the distinct life cycles of TCBQ and DBBQ in drinking water , covering formation, transformation, and toxicity. These findings provide a nuanced understanding of the risks posed by HBQs at various locations within the drinking water distribution system , offering valuable guidance for improving the control of DBPs in drinking water .
研究领域:
环境科学
·
公共卫生
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 28
·期 44
·62519-62529
·
IF 4.223
Chang Jingyi,Xiang Wenrui,Qu Ruijuan,Sun Cheng,Wang Zunyao,Zhu Feng,Huo Zongli
Bisphenol AF (BPAF), commonly used as a substitute for bisphenol A (BPA), is also an endocrine disruptor with cytotoxicity, neurotoxicity, genotoxicity, and biotoxicity. In this study, we found that BPAF could be effectively degraded by free chlorine. The second order rate constant of the reaction ranged from 1.67 to 126.67 M −1 ·s −1 in the pH range of 5.0–11.0. Nineteen products were detected by LC-Q-TOF-MS analysis, including chlorinated BPAF (i.e., mono/di/tri/tetrachloro-BPAF), 8 dimers, and 6 trimers. According to the identified products, two transformation pathways of electrophilic substitution and electron transfer are proposed. Humic acid (HA) could inhibit the degradation rate of BPAF due to its ability to reduce the reactive BPAF radical intermediates to the parent compound. The addition of low concentrations of Br − and I − accelerates the reaction rate of BPAF, due to the formation of HOBr and HOI with a higher oxidizing capacity. In seawater, BPAF degraded rapidly, and 16 new halogenated products were formed. Theoretical calculation shows that electrophilic substitution is more prone to occur at the ortho position of the hydroxyl group to form chlorinated products, while electron transfer tends to occur at the hydroxyl oxygen, resulting in the formation of BPAF radical and its subsequent coupling products.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
PubMed
高影响因子
Frontiers of Environmental Science & Engineering
·
2025
·Vol. 19
·期 4
·1-13
·
IF 6.4
Jiang Linke,Li Yong,Shi Shuiqin,Yan Junmei,Chi Lianbao,Liu Hui,Feng Mingbao
Chlorinating wastewater before it is released into surface water can change the fate of organic pollutants. This transformation is influenced by chlorine residues, bromine-containing wastewater, and solar radiation. Losartan (LOS), one of the earliest sartan antihypertensive drugs produced, is used worldwide and has been found in the environment. However, its transformation mechanisms and environmental risks have not been systematically investigated. This research presents the degradation kinetics, transformation products, and environmental risks of LOS in different scenarios. The results revealed that k app, HClO (LOS) ranged from 0.47 to 8.30 L/(mol·s) at pH 5.0–8.0. The k app, HBrO (LOS) values at pH 5.0–8.0 ranged from 8.38 × 10 3 to 1.55 × 10 5 L/(mol·s), revealing a faster bromination reaction than chlorination. LOS degrades through direct photolysis, carbonate radicals (CO 3 / •− ), and singlet oxygen ( 1 O 2 ) under sunlight exposure. The solar/chlorination process accelerates the reaction rate through radical activity. In addition, chlorination and bromination resulted in halogen addition to the aromatic ring, whereas hydroxylation, hydrogen abstraction, demethylation, ring opening, and hydrolysis reactions were observed across all processes. Some products exhibit high biodegradation resistance and high toxicity, potentially threatening the aquatic environment. This study aims to enhance our understanding of the environmental behavior and resulting risks of LOS by exploring its environmental fate through various transformation processes.
研究领域:
环境科学
·
药理学
✓ 已验证
DOI
高影响因子
WATER AIR AND SOIL POLLUTION
·
2017
·Vol. 228
·期 6
·1-9
·
IF 1.702
Gan Guojuan,Qiu Lin,Wu Huan,Hong Huachang,Mazumder Asit,Pan Xiangliang,Liang Yan
Occurrence of halonitromethanes (HNMs) in drinking water has been a concern recently due to the potentially high human health risks of HNMs. Mechanisms of formation of HNMs during disinfection has remained controversial. The objective of this study was to investigate the effects of nitrite on the formation of trichloronitromethane (TCNM), a dominant HNM species occurring in chlorinated water. Polyhydroxy-phenols (hydroquinone, catechol, resorcinol, and phloroglucinol) and sugars (glucose, maltose, and lactose) were compared as surrogates/model compounds of common organic precursors of humic and non-humic substances in natural organic matter, respectively. The results showed that TCNM was not detectable after chlorinated sugars with the addition of nitrite. Upon chlorinating the polyhydroxy-phenols, TCNM formation varied greatly among different compounds, i.e., resorcinol > phloroglucinol > catechol >> hydroquinone. The results demonstrated that TCNM formation in the presence of nitrite was a function of aromaticity as well as the position and number of hydroxyl groups on the benzene rings of a compound, and the TCNM formation potential of humic substances was greater than that of non-humic substances. For catechol, resorcinol, and phloroglucinol, TCNM formation varied greatly with pH but generally remained stable with the increase of reaction time and temperature.
研究领域:
环境科学
·
公共卫生
✓ 已验证
DOI
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Wuming Wang,Zichong Zhou,Shunke Ding,Wenyuan Yang,Wei Jin,Wenhai Chu,Zuxin Xu
Ambroxol hydrochloride (AMB) and bromhexine hydrochloride (BRO) are classic expectorants and bronchosecretolytic pharmaceuticals. In 2022, both AMB and BRO were recommended by medical emergency department of China to alleviate cough and expectoration for symptoms caused by COVID-19. The reaction characteristics and mechanism of AMB/BRO with chlorine disinfectant in the disinfection process were investigated in this study. The reaction of chlorine with AMB/BRO were well described by a second-order kinetics model, first-order in both AMB/BRO and chlorine. The second order rate reaction constant of AMB and BRO with chlorine at pH 7.0 were 1.15 × 10 2 M −1 s −1 and 2.03 × 10 2 M −1 s −1 , respectively. During chlorination, a new class of aromatic nitrogenous disinfection by-products (DBPs) including 2-chloro-4, 6-dibromoaniline and 2, 4, 6-tribromoaniline were identified as the intermediate aromatic DBPs by gas chromatography-mass spectrometry. The effect of chlorine dosage, pH, and contact time on the formation of 2-chloro-4, 6-dibromoaniline and 2, 4, 6-tribromoaniline were evaluated. In addition, it was found that bromine in AMB/BRO were vital bromine source to greatly promote the formation of classic brominated DBPs, with the highest Br-THMs yields of 23.8% and 37.8%, respectively. This study inspired that bromine in brominated organic compounds may be an important bromine source of brominated DBPs.
研究领域:
环境科学
·
公共卫生
·
药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2018
·
IF 7.051
Shunke Ding,Wenhai Chu,Stuart W. Krasner,Yun Yu,Chao Fang,Bin Xu,Naiyun Gao
Haloacetamides (HAMs), a group of nitrogenous disinfection byproducts (N-DBPs), can decompose to form corresponding intermediate products and other DBPs. The stability of ten different HAMs, including two chlorinated, five brominated, and three iodinated species was investigated with and without the presence of chlorine, chloramines, and reactive solutes such as quenching agents. The HAM basic hydrolysis and chlorination kinetics were well described by a second-order kinetics model, including first-order in HAM and hydroxide and first-order in HAM and hypochlorite, respectively, whereas the HAM neutral hydrolysis kinetic was first-order in HAM. Furthermore, HAMs decompose instantaneously when exposed to hypochlorite, which was almost two and nine orders of magnitude faster than HAM basic and neutral hydrolysis, respectively. In general, HAM hydrolysis and chlorination rates both increased with increasing pH and the number of halogens substituted on the methyl group. Moreover, chlorinated HAMs are more unstable than their brominated analogs, followed by the iodinated ones, due to the decrease in the electron-withdrawing inductive effect from chlorine to iodine atom. During hydrolysis, HAMs mainly directly decompose into the corresponding haloacetic acids (HAAs) via a nucleophilic reaction between the carbonyl carbon and hydroxide. For HAM chlorination reactions, hypochlorite reacts with HAMs to form the N -chloro-HAMs ( N -Cl-HAMs) via Cl + transfer from chlorine to the amide nitrogen. N -Cl-HAMs can further degrade to form HAAs via hypochlorous acid addition. In contrast, the reactions between chloramines and HAMs were found to be insignificant. Additionally, four common quenching agents, including sodium sulfite , sodium thiosulfate , ascorbic acid , and ammonium chloride , were demonstrated to expedite HAM degradation, whereas ammonium chloride was the least influential among the four. Taft linear free energy relationships were established for both HAM hydrolysis and chlorination reactions, based on which the hydrolysis and chlorination rate constants for three monohaloacetamides were estimated. The hydrolysis and chlorination rates of 13 HAMs decreased in the following order: TCAM > BDCAM > DBCAM > TBAM > DCAM > BCAM > DBAM > CIAM > BIAM > DIAM > MCAM > MBAM > MIAM (where C = chloro, B = bromo, I = iodo, T = tri, D = di, M = mono). Lastly, using the HAM kinetic model established in this study, HAM half-lifes in drinking water distribution systems can be predicted on the basis of pH and residual chlorine concentration.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Haoliang Xiao,Zhuqi Chen,Jiaqi Ding,Ning Zhang,Zhimin Ye,Zhonghua Xiao,Songlin Wang,Pengchao Xie,Yongsheng Chen
In chemical membrane cleaning, the challenge is to efficiently remove irreversible fouling while minimizing the impact on membrane materials. Particularly, traditional hypochlorite cleaning will further lead to the generation of toxic halogenated by-products. To address these issues, a combined system composed of peroxymonosulfate and chloride (PMS/Cl − ) was applied to clean irreversible-humic-acid-fouled polyethersulfone (PES) membranes. After fouled membranes were soaked for 1 h in a PMS/Cl − solution (10 mM/15 mM) at 25 °C under neutral conditions, 94% flux recovery and 96% resistance removal were realized. Surface properties of virgin and cleaned membranes were very similar, confirming the effectiveness of the PMS/Cl − solution in removing irreversible foulants. The stability of membrane separation performance during multiple fouling and cleaning cycles further confirmed the minimal impact on membrane materials. Rapid diminution of the peaks centered in the region of fulvic-like and humic-like components, monitored under 3D-fluorescence for the cleaning solution, was attributed to PMS-catalyzed chlorination, thereby revealing the primary foulant detachment mechanism. Crucially, the approach exhibited lower toxicity than hypochlorite, as evidenced by reduced halogenated by-products and lower acute toxicity to Photobacterium phosphoreum T3. Overall, this novel cleaning system is promising for the efficient and environmentally friendly removal of irreversible organic foulants in practical water-treatment.
研究领域:
环境科学
·
化学工程
·
水处理技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER AIR AND SOIL POLLUTION
·
2023
·Vol. 234
·期 8
·1-13
·
IF 2.9
You Yu,Liu Haicheng
With the increased use of microplastics and antibiotics in modern society, a large number of microplastics and antibiotics are being found in natural and water treatment systems. In this paper, the effect of polypropylene (PP), polyethylene (PE), and polystyrene (PS) microplastics (MPs) on the chlorination of ciprofloxacin (CIP) and subsequent production of disinfection byproducts (DBPs) was investigated using sodium hypochlorite (NaClO) as the disinfectant and trichloromethane (CHCl 3 ) and dichloroacetonitrile (DCAN) as typical carbon- and nitrogen-containing disinfection byproducts. Disinfection byproducts (DBPs) were investigated. The results showed that the mass concentrations of CHCl 3 and DCAN generated after CIP chlorination were higher, reaching 160.1 μg/L and 2.5 μg/L, respectively, than those generated after the chlorination of microplastics (0.49~41 μg/L). Considering the effect of microplastics on the chlorination of ciprofloxacin to generate disinfection byproducts, it was found that the increase in the production of CHCl 3 and DCAN was not significant and that production even tended to decrease. There was a slight contribution to the generation of CHCl 3 with increasing microplastic concentration. There was almost no effect on DCAN, and the generation of DCAN was even inhibited. Increases in pH, NaClO dose, and chlorination time promoted the generation of CHCl 3 , but DCAN showed a decreasing trend due to its instability and easy decomposition. This study provides a theoretical basis for understanding the generation of disinfection byproducts in water sources contaminated by microplastics and antibiotics.
研究领域:
环境科学
·
公共卫生
·
化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）