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Sun Y, Liu L, Li M, Xu F, Yu W. Theoretical evidence for the formation of perfluorocarboxylic acids form atmospheric oxidation degradation of fluorotelomer acrylates. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:55092-55104. [PMID: 35312922 DOI: 10.1007/s11356-022-19788-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
The atmospheric oxidation degradation of fluorotelomer acrylates (FTAcs) has been proposed as a potential source of perfluorocarboxylic acids (PFCAs) in remote locations. In this paper, detailed reactions of the main oxidant OH radicals with 4:2 FTAc in the atmosphere have been investigated by using density functional theory (DFT) calculation. All possible pathways involved in the oxidation process were presented and discussed. Based on the mechanism, transition state theory (TST) was used to predict the rate constants of the key elementary steps including the initial reactions of OH radical with n:2 FTAcs and the subsequent reactions of the main intermediates. Studies show that the reaction processes of OH radical addition to C = C bond are dominant and the fluorotelomer glyoxylate and formaldehyde are the major products. At 296 K, the calculated overall rate constant of 4:2 FTAc with OH radical is 1.19 × 10-11 cm3 molecule-1 s-1 with an atmospheric lifetime of 23.3 h. In the atmosphere, fluorotelomer glyoxylate will continue to be oxidized, which will lead to the formation of PFCAs ultimately. In addition, atmospheric reactions of more carbons FTAc (CnF2n+1CH2CH2OC(O)CH = CH2, n = 6, 8, 10) are also discussed in the presence of O2/NOx.
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Affiliation(s)
- Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, People's Republic of China.
| | - Lin Liu
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, People's Republic of China
| | - Ming Li
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, People's Republic of China
| | - Fei Xu
- Environment Research Institute, Shandong University, Qingdao, 266237, People's Republic of China
| | - Wanni Yu
- Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, College of Resources and Environment, Linyi University, Linyi, 276005, People's Republic of China
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Straccia C VG, Lugo PL, Rivela CB, Blanco MB, Wiesen P, Teruel MA. OH-initiated degradation of methyl 2-chloroacetoacetate and ethyl 2-chloroacetoacetate: Kinetics, products and mechanisms at 298 K and atmospheric pressure. CHEMOSPHERE 2021; 274:129659. [PMID: 33549882 DOI: 10.1016/j.chemosphere.2021.129659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
Rate coefficients for the gas-phase reactions of OH radicals with CH3C(O)CHClC(O)OCH3 (k1) and CH3C(O)CHClC(O)OCH2CH3 (k2) were measured using the relative technique with different reference compounds. The experiments were performed at (298 ± 2) K and 750 Torr of nitrogen or synthetic air by in situ FTIR spectroscopy and GC-FID chromatography. The following rate coefficients (in units of cm3molecule-1 s-1) were obtained: k1FTIR= (2.70 ± 0.51) × 10-11; k1GC-FID= (2.30 ± 0.71) × 10-11 and k2FTIR= (3.37 ± 0.62) × 10-11; k2GC-FID= (3.26 ± 0.85) × 10-11. This work reports the first kinetic study for the reactions of OH radicals with the mentioned chloroacetoacetates. Additionally, product studies are reported in similar conditions of the kinetic experiments. Acetic acid, acetaldehyde, formyl chloride, and methyl 2-chloro-2-oxoacetate were positively identified and quantified as degradation products. According to the identified products, atmospheric chemical mechanisms were proposed. The environmental implications of these reactions were assessed by the tropospheric lifetimes calculations of the title chloroesters. Significant average ozone production of 4.16 ppm for CH3C(O)CHClC(O)OCH3 and 5.98 ppm for CH3C(O)CHClC(O)OCH2CH3, respectively were calculated.
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Affiliation(s)
- Vianni G Straccia C
- (L.U.Q.C.A), Laboratorio Universitario de Química y Contaminación del Aire, Instituto de Investigaciones en Fisicoquímica de Córdoba (I.N.F.I.Q.C.), Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina
| | - Pedro L Lugo
- (L.U.Q.C.A), Laboratorio Universitario de Química y Contaminación del Aire, Instituto de Investigaciones en Fisicoquímica de Córdoba (I.N.F.I.Q.C.), Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina
| | - Cynthia B Rivela
- (L.U.Q.C.A), Laboratorio Universitario de Química y Contaminación del Aire, Instituto de Investigaciones en Fisicoquímica de Córdoba (I.N.F.I.Q.C.), Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina
| | - Maria B Blanco
- (L.U.Q.C.A), Laboratorio Universitario de Química y Contaminación del Aire, Instituto de Investigaciones en Fisicoquímica de Córdoba (I.N.F.I.Q.C.), Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina
| | - Peter Wiesen
- Institute for Atmospheric and Environmental Research, University of Wuppertal, DE-42097, Wuppertal, Germany
| | - Mariano A Teruel
- (L.U.Q.C.A), Laboratorio Universitario de Química y Contaminación del Aire, Instituto de Investigaciones en Fisicoquímica de Córdoba (I.N.F.I.Q.C.), Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000, Córdoba, Argentina.
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Qu R, Liu J, Li C, Wang L, Wang Z, Wu J. Experimental and theoretical insights into the photochemical decomposition of environmentally persistent perfluorocarboxylic acids. WATER RESEARCH 2016; 104:34-43. [PMID: 27508972 DOI: 10.1016/j.watres.2016.07.071] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/18/2016] [Accepted: 07/29/2016] [Indexed: 06/06/2023]
Abstract
Decomposition of perfluorocarboxylic acids (PFCAs) is of great significance due to their global distribution, persistence and toxicity to organisms. In this study, the photodegradation of a series of PFCAs (∼C2C12) in water by a medium-pressure mercury lamp was experimentally and theoretically examined. We found that photolysis of PFCAs all follow pseudo-first-order kinetics with the rate constant (kapp) increasing with carbon chain lengths, except for trifluoroacetic acid (TFA) which cannot be degraded by the polychromatic irradiation. Product analysis showed that the PFCAs were mainly decomposed into shorter carbon chain length PFCAs in a stepwise manner, with the accumulation of TFA and fluoride ions as the end products. Moreover, a small amount of perfluoroolefins (CnF2n) was determined as gas-phase products. Wiberg bond order calculations confirmed the cleavage of the CC bond between carboxylic carbon and the adjacent carbon as the first reaction step, and density functional theory-based calculations revealed that kapp value is correlated with some molecular structural parameters. In the case of mixture irradiation, the evolution profiles of individual PFCAs were different from that in single-component systems, due to the dynamic balance between production and degradation. This work reveals the main molecular descriptors controlling the degradation rate of different PFCAs species, and improves the general understanding on the photodegradation mechanisms, which will provide useful information for future researches.
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Affiliation(s)
- Ruijuan Qu
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu, Nanjing 210023, PR China
| | - Jiaoqin Liu
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu, Nanjing 210023, PR China
| | - Chenguang Li
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu, Nanjing 210023, PR China
| | - Liansheng Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu, Nanjing 210023, PR China
| | - Zunyao Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Jiangsu, Nanjing 210023, PR China.
| | - Jichun Wu
- Key Laboratory of Surficial Geochemistry, Ministry of Education, School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing 210023, PR China.
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Blanco MB, Barnes I, Wiesen P, Teruel MA. Atmospheric sink of methyl chlorodifluoroacetate and ethyl chlorodifluoroacetate: temperature dependent rate coefficients, product distribution of their reactions with Cl atoms and CF2ClC(O)OH formation. RSC Adv 2016. [DOI: 10.1039/c6ra03454c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rate coefficients as a function of temperature and product distribution studies have been performed for the first time for the gas-phase reactions of chlorine atoms with methyl chlorodifluoracetate (k1) and ethyl chlorodifluoroacetate (k2) using the relative rate technique.
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Affiliation(s)
- María B. Blanco
- CONICET
- Instituto de Investigaciones en Fisicoquímica
- I.N.F.I.Q.C
- Facultad de Ciencias Químicas
- Universidad Nacional de Córdoba
| | - Ian Barnes
- Bergische Universität Wuppertal
- Fakultät für Mathematik und Naturwissenschaften
- Physikalische & Theoretische Chemie
- 42119 Wuppertal
- Germany
| | - Peter Wiesen
- Bergische Universität Wuppertal
- Fakultät für Mathematik und Naturwissenschaften
- Physikalische & Theoretische Chemie
- 42119 Wuppertal
- Germany
| | - Mariano A. Teruel
- CONICET
- Instituto de Investigaciones en Fisicoquímica
- I.N.F.I.Q.C
- Facultad de Ciencias Químicas
- Universidad Nacional de Córdoba
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