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Xu T, Nie W, Xu Z, Yan C, Liu Y, Zha Q, Wang R, Li Y, Wang L, Ge D, Chen L, Qi X, Chi X, Ding A. Investigation on the budget of peroxyacetyl nitrate (PAN) in the Yangtze River Delta: Unravelling local photochemistry and regional impact. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170373. [PMID: 38286297 DOI: 10.1016/j.scitotenv.2024.170373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/12/2024] [Accepted: 01/21/2024] [Indexed: 01/31/2024]
Abstract
Peroxyacetyl nitrate (PAN) is a significant indicator of atmospheric photochemical pollution, which can influence the regional distribution of ozone (O3) and hydroxyl radical (OH) through long-range transport. However, investigations of PAN incorporating comprehensive measurement and explicit modeling analysis are limited, hindering complete understandings of its temporal behavior, sources, and impacts on photochemistry. Here we conducted a 1-year continuous observation of PAN and relative atmospheric species in Nanjing located in Yangtze River Delta (YRD). The annual mean concentration of PAN was 0.62 ± 0.49 ppbv and showed a bimodal monthly variation, peaking in April-June and November-January, respectively. This pattern is different from the typical pattern of photochemistry, suggesting important contributions of other non-photochemical processes. We further analyzed the PAN budget using an observation-based model, by which, PAN from local photochemical production and regional source could be decoupled. Our results revealed that local photochemical production of PAN is the sole contributor to PAN in summer, whereas about half of the total PAN concentration is attributed to regional source in winter. Although the formation of PAN can suppress the atmospheric oxidation capacity by consuming the peroxyacetyl radical and nitrogen dioxide (NO2), our analyses suggested this effect is minor at our station (-3.2 ± 1.1 % in summer and - 7.2 ± 2.8 % in winter for O3 formation). However, it has the potential to enhance O3 and OH formation by 14.16 % and 5.93 %, if transported to cleaner environments with air pollutants halved. Overall, our study highlights the importance of both local photochemistry and regional process in PAN budget and provides a useful evaluation on the impact of PAN on atmospheric oxidation capacity.
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Affiliation(s)
- Tao Xu
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Wei Nie
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China.
| | - Zheng Xu
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China; Jiangsu Provincial Environmental Monitoring Center, Nanjing, Jiangsu 210036, China.
| | - Chao Yan
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Yuliang Liu
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Qiaozhi Zha
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Ruoxian Wang
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Yuanyuan Li
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Lei Wang
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Dafeng Ge
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Liangduo Chen
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Ximeng Qi
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Xuguang Chi
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
| | - Aijun Ding
- Joint International Research Laboratory of Atmospheric and Earth System Research, School of Atmospheric Sciences, Nanjing University, Nanjing, Jiangsu 210023, China; National Observation and Research Station for Atmospheric Processes and Environmental Change in Yangtze River Delta, Nanjing, Jiangsu Province, China
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Salo VT, Chen J, Runeberg N, Kjaergaard HG, Kurtén T. Multireference and Coupled-Cluster Study of Dimethyltetroxide (MeO 4Me) Formation and Decomposition. J Phys Chem A 2024. [PMID: 38417845 DOI: 10.1021/acs.jpca.3c08043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2024]
Abstract
Peroxyl radicals (RO2) are important intermediates in the atmospheric oxidation processes. The RO2 can react with other RO2 to form reactive intermediates known as tetroxides, RO4R. The reaction mechanisms of RO4R formation and its various decomposition channels have been investigated in multiple computational studies, but previous approaches have not been able to provide a unified methodology that is able to connect all relevant reactions together. An apparent difficulty in modeling the RO4R formation and its decomposition is the involvement of open-shell singlet electronic states along the reaction pathway. Modeling such electronic states requires multireference (MR) methods, which we use in the present study to investigate in detail a model reaction of MeO2 + MeO2 → MeO4Me, and its decomposition, MeO4Me → MeO + O2 + MeO, as well as the two-body product complexes MeO···O2 + MeO and MeO···MeO + O2. The used MR methods are benchmarked against relative energies of MeO2 + MeO2, MeO4Me, and MeO + MeO + O2, calculated with CCSD(T)/CBS, W2X, and W3X-L methods. We found that the calculated relative energies of the overall MeO2 + MeO2 → MeO4Me → MeO + O2 + MeO reaction are very sensitive to the chosen MR method and that the CASPT2(22e,14o)-IPEA method is able to reproduce the relative energies obtained by the various coupled-cluster methods. Furthermore, CASPT2(22e,14o)-IPEA and W3X-L results show that the MeO···O2 product complex + MeO is lower in energy than the MeO···MeO complex + O2. The formation of MeO4Me is exothermic, and its decomposition is endothermic, relative to the tetroxide. Both the formation and decomposition reactions appear to follow pathways with no saddle points. According to potential energy surface scans of the decomposition pathway, the concerted cleavage of both MeO···O bonds in MeO4Me is energetically preferred over the corresponding sequential decomposition.
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Affiliation(s)
- Vili-Taneli Salo
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FI-00014, Finland
| | - Jing Chen
- Department of Chemistry, University of Copenhagen, Copenhagen 2100, Denmark
| | - Nino Runeberg
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FI-00014, Finland
| | | | - Theo Kurtén
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FI-00014, Finland
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Zhang H, Tong S, Zhang W, Xu Y, Zhai M, Guo Y, Li X, Wang L, Tang G, Liu Z, Hu B, Liu C, Liu P, Sun X, Mu Y, Ge M. A comprehensive observation on the pollution characteristics of peroxyacetyl nitrate (PAN) in Beijing, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:166852. [PMID: 37717750 DOI: 10.1016/j.scitotenv.2023.166852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/28/2023] [Accepted: 09/03/2023] [Indexed: 09/19/2023]
Abstract
Peroxyacetyl nitrate (PAN) is a typical secondary photochemical product in the atmospheric environment with significant adverse effects on human health and plant growth. In this study, PAN and other pollutants, as well as meteorological conditions were observed intensively from August to September in 2022 at a typical urban sampling site in Beijing, China. The mean and maximum PAN concentrations during the observation period were 1.00 ± 0.97 ppb and 4.84 ppb, respectively. Severe photochemical pollution occurred during the observation period, with the mean PAN concentration about 3.1 times higher than that during the clean period. There was a good positive correlation between O3 and PAN, and their correlation was higher during the O3 exposure period than that during the clean period. The simulated results by box-model coupled with the Master Chemical Mechanism (MCM v3.3.1) showed that the O3-related reactions were the largest sources of OH radicals during O3 exposure period, which was conducive to the co-contamination of PAN and O3. Acetaldehyde (CH3CHO) and methylglyoxal (MGLY) were the largest OVOCs precursors of peroxyacetyl radicals (PA), with the contributions to the total PA generated by OVOCs about 67 % - 83 % and 17 % - 30 %, respectively. The reduction of emissions from liquefied petroleum gas (LPG) and solvent usage has the highest reduction effect on PAN and O3, followed by the control of gasoline vehicle exhaust emissions. This study deepens the understanding of the PAN photochemistry in urban areas with high O3 background conditions and the impact of anthropogenic activities on the photochemical pollution. Meanwhile, the findings of this study highlight the necessity of strengthening anthropogenic emissions control to effectively reduce the co-contamination of PAN and O3 in Beijing in the future.
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Affiliation(s)
- Hailiang Zhang
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
| | - Shengrui Tong
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China.
| | - Wenqian Zhang
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
| | - Yanyong Xu
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Mingzhu Zhai
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yucong Guo
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
| | - Xin Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Lili Wang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, Beijing 100029, PR China
| | - Guiqian Tang
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, Beijing 100029, PR China
| | - Zirui Liu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, Beijing 100029, PR China
| | - Bo Hu
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics (IAP), Chinese Academy of Sciences, Beijing 100029, PR China
| | - Chengtang Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Pengfei Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Xu Sun
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; Beijing Urban Ecosystem Research Station State Key Laboratory of Urban and Regional Ecology Research Center for Eco- Environmental Sciences Chinese Academy of Sciences, Beijing 100085, PR China
| | - Yujing Mu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China
| | - Maofa Ge
- State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
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Zuraski K, Grieman FJ, Hui AO, Cowen J, Winiberg FAF, Percival CJ, Okumura M, Sander SP. Acetonyl Peroxy and Hydroperoxy Self- and Cross-Reactions: Temperature-Dependent Kinetic Parameters, Branching Fractions, and Chaperone Effects. J Phys Chem A 2023; 127:7772-7792. [PMID: 37683115 PMCID: PMC10518823 DOI: 10.1021/acs.jpca.3c03660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/01/2023] [Indexed: 09/10/2023]
Abstract
The temperature-dependent kinetic parameters, branching fractions, and chaperone effects of the self- and cross-reactions between acetonyl peroxy (CH3C(O)CH2O2) and hydro peroxy (HO2) have been studied using pulsed laser photolysis coupled with infrared (IR) wavelength-modulation spectroscopy and ultraviolet absorption (UVA) spectroscopy. Two IR lasers simultaneously monitored HO2 and hydroxyl (OH), while UVA measurements monitored CH3C(O)CH2O2. For the CH3C(O)CH2O2 self-reaction (T = 270-330 K), the rate parameters were determined to be A = (1.5-0.3+0.4) × 10-13 and Ea/R = -996 ± 334 K and the branching fraction to the alkoxy channel, k2b/k2, showed an inverse temperature dependence following the expression, k2b/k2 = (2.27 ± 0.62) - [(6.35 ± 2.06) × 10-3] T(K). For the reaction between CH3C(O)CH2O2 and HO2 (T = 270-330 K), the rate parameters were determined to be A = (3.4-1.5+2.5) × 10-13 and Ea/R = -547 ± 415 K for the hydroperoxide product channel and A = (6.23-4.4+15.3) × 10-17 and Ea/R = -3100 ± 870 K for the OH product channel. The branching fraction for the OH channel, k1b /k1, follows the temperature-dependent expression, k1b/k1 = (3.27 ± 0.51) - [(9.6 ± 1.7) × 10-3] T(K). Determination of these parameters required an extensive reaction kinetics model which included a re-evaluation of the temperature dependence of the HO2 self-reaction chaperone enhancement parameters due to the methanol-hydroperoxy complex. The second-law thermodynamic parameters for KP,M for the formation of the complex were found to be ΔrH250K° = -38.6 ± 3.3 kJ mol-1 and ΔrS250K° = -110.5 ± 13.2 J mol-1 K-1, with the third-law analysis yielding ΔrH250K° = -37.5 ± 0.25 kJ mol-1. The HO2 self-reaction rate coefficient was determined to be k4 = (3.34-0.80+1.04) × 10-13 exp [(507 ± 76)/T]cm3 molecule-1 s-1 with the enhancement term k4,M″ = (2.7-1.7+4.7) × 10-36 exp [(4700 ± 255)/T]cm6 molecule-2 s-1, proportional to [CH3OH], over T = 220-280 K. The equivalent chaperone enhancement parameter for the acetone-hydroperoxy complex was also required and determined to be k4,A″ = (5.0 × 10-38 - 1.4 × 10-41) exp[(7396 ± 1172)/T] cm6 molecule-2 s-1, proportional to [CH3C(O)CH3], over T = 270-296 K. From these parameters, the rate coefficients for the reactions between HO2 and the respective complexes over the given temperature ranges can be estimated: for HO2·CH3OH, k12 = [(1.72 ± 0.050) × 10-11] exp [(314 ± 7.2)/T] cm3 molecule-1 s-1 and for HO2·CH3C(O)CH3, k15 = [(7.9 ± 0.72) × 10-17] exp [(3881 ± 25)/T] cm3 molecule-1 s-1. Lastly, an estimate of the rate coefficient for the HO2·CH3OH self-reaction was also determined to be k13 = (1.3 ± 0.45) × 10-10 cm3 molecule-1 s-1.
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Affiliation(s)
- Kristen Zuraski
- NASA
Jet Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Fred J. Grieman
- NASA
Jet Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
- Seaver
Chemistry Laboratory, Pomona College, Claremont, California 91711, United States
| | - Aileen O. Hui
- Arthur
Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Julia Cowen
- NASA
Jet Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
- Seaver
Chemistry Laboratory, Pomona College, Claremont, California 91711, United States
| | - Frank A. F. Winiberg
- NASA
Jet Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Carl J. Percival
- NASA
Jet Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Mitchio Okumura
- Arthur
Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Stanley P. Sander
- NASA
Jet Propulsion Laboratory, California Institute
of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
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Zhang C, Li C, Zhang W, Tang X, Pillier L, Schoemaecker C, Fittschen C. Rate constant and branching ratio of the reaction of ethyl peroxy radicals with methyl peroxy radicals. Phys Chem Chem Phys 2023. [PMID: 37377107 DOI: 10.1039/d3cp01141k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
The cross-reaction of ethyl peroxy radicals (C2H5O2) with methyl peroxy radicals (CH3O2) (R1) has been studied using laser photolysis coupled to time resolved detection of the two different peroxy radicals by continuous wave cavity ring down spectroscopy (cw-CRDS) in their AÃ-X̃ electronic transition in the near-infrared region, C2H5O2 at 7602.25 cm-1, and CH3O2 at 7488.13 cm-1. This detection scheme is not completely selective for both radicals, but it is demonstrated that it has great advantages compared to the widely used, but unselective UV absorption spectroscopy. Peroxy radicals were generated from the reaction of Cl-atoms with the appropriate hydrocarbon (CH4 and C2H6) in the presence of O2, whereby Cl-atoms were generated by 351 nm photolysis of Cl2. For different reasons detailed in the manuscript, all experiments were carried out under excess of C2H5O2 over CH3O2. The experimental results were best reproduced by an appropriate chemical model with a rate constant for the cross-reaction of k = (3.8 ± 1.0) × 10-13 cm3 s-1 and a yield for the radical channel, leading to CH3O and C2H5O, of (ϕ1a = 0.40 ± 0.20).
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Affiliation(s)
- Cuihong Zhang
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- Science Island Branch, Graduate School, University of Science and Technology of China, Hefei 230026, Anhui, China
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
| | - Chuanliang Li
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
- Shanxi Engineering Research Center of Precision Measurement and Online Detection Equipment and School of Applied Science, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Weijun Zhang
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xiaofeng Tang
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Laure Pillier
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
| | - Coralie Schoemaecker
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
| | - Christa Fittschen
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France.
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Douroudgari H, Zarepour H, Vahedpour M, Jaberi M, Zarepour M. The atmospheric relevance of primary alcohols and imidogen reactions. Sci Rep 2023; 13:9150. [PMID: 37277419 DOI: 10.1038/s41598-023-35473-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 05/18/2023] [Indexed: 06/07/2023] Open
Abstract
Organic alcohols as very volatile compounds play a crucial role in the air quality of the atmosphere. So, the removal processes of such compounds are an important atmospheric challenge. The main goal of this research is to discover the atmospheric relevance of degradation paths of linear alcohols by imidogen with the aid of simulation by quantum mechanical (QM) methods. To this end, we combine broad mechanistic and kinetic results to get more accurate information and to have a deeper insight into the behavior of the designed reactions. Thus, the main and necessary reaction pathways are explored by well-behaved QM methods for complete elucidation of the studying gaseous reactions. Moreover, the potential energy surfaces as a main factor are computed for easier judging of the most probable pathways in the simulated reactions. Our attempt to find the occurrence of the considered reactions in the atmospheric conditions is completed by precisely evaluating the rate constants of all elementary reactions. All of the computed bimolecular rate constants have a positive dependency on both temperature and pressure. The kinetic results show that H-abstraction from the α carbon is dominant relative to the other sites. Finally, by the results of this study, we conclude that at moderate temperatures and pressures primary alcohols can degrade with imidogen, so they can get atmospheric relevance.
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Affiliation(s)
- Hamed Douroudgari
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran.
| | - Hadi Zarepour
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran
| | - Morteza Vahedpour
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran.
| | - Mahdi Jaberi
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran
| | - Mahdi Zarepour
- Department of Chemistry, University of Zanjan, PO Box 38791-45371, Zanjan, Iran
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7
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Gao Y, Lu K, Zhang Y. Review of technologies and their applications for the speciated detection of RO 2 radicals. J Environ Sci (China) 2023; 123:487-499. [PMID: 36522008 DOI: 10.1016/j.jes.2022.09.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 09/17/2022] [Accepted: 09/19/2022] [Indexed: 06/17/2023]
Abstract
Peroxy radicals (RO2), which are formed during the oxidation of volatile organic compounds, play an important role in atmospheric oxidation reactions. Therefore, the measurement of RO2, especially distinct species of RO2 radicals, is important and greatly helps the exploration of atmospheric chemistry mechanisms. Although the speciated detection of RO2 radicals remains challenging, various methods have been developed to study them in detail. These methods can be divided into spectroscopy and mass spectrometry technologies. The spectroscopy methods contain laser-induced fluorescence (LIF), UV-absorption spectroscopy, cavity ring-down spectroscopy (CRDS) and matrix isolation and electron spin resonance (MIESR). The mass spectrometry methods contain chemical ionization atmospheric pressure interface time-of-flight mass spectrometry (CI-APi-TOF), chemical ionization mass spectrometry (CIMS), CI-Orbitrap-MS and the third-generation proton transfer reaction-time-of-flight mass spectrometer (PTR3). This article reviews technologies for the speciated detection of RO2 radicals and the applications of these methods. In addition, a comparison of these techniques and the reaction mechanisms of some key species are discussed. Finally, possible gaps are proposed that could be filled by future research into speciated RO2 radicals.
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Affiliation(s)
- Yue Gao
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Keding Lu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
| | - Yuanhang Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
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Dummer NF, Willock DJ, He Q, Howard MJ, Lewis RJ, Qi G, Taylor SH, Xu J, Bethell D, Kiely CJ, Hutchings GJ. Methane Oxidation to Methanol. Chem Rev 2022; 123:6359-6411. [PMID: 36459432 PMCID: PMC10176486 DOI: 10.1021/acs.chemrev.2c00439] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The direct transformation of methane to methanol remains a significant challenge for operation at a larger scale. Central to this challenge is the low reactivity of methane at conditions that can facilitate product recovery. This review discusses the issue through examination of several promising routes to methanol and an evaluation of performance targets that are required to develop the process at scale. We explore the methods currently used, the emergence of active heterogeneous catalysts and their design and reaction mechanisms and provide a critical perspective on future operation. Initial experiments are discussed where identification of gas phase radical chemistry limited further development by this approach. Subsequently, a new class of catalytic materials based on natural systems such as iron or copper containing zeolites were explored at milder conditions. The key issues of these technologies are low methane conversion and often significant overoxidation of products. Despite this, interest remains high in this reaction and the wider appeal of an effective route to key products from C-H activation, particularly with the need to transition to net carbon zero with new routes from renewable methane sources is exciting.
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Affiliation(s)
- Nicholas F. Dummer
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - David J. Willock
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Qian He
- Department of Materials Science and Engineering, National University of Singapore, Singapore117575, Singapore
| | - Mark J. Howard
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Richard J. Lewis
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Guodong Qi
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, P. R. China
- University of Chinese Academy of Sciences, Beijing100049, P. R. China
| | - Stuart H. Taylor
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
| | - Jun Xu
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan430071, P. R. China
- University of Chinese Academy of Sciences, Beijing100049, P. R. China
| | - Don Bethell
- Department of Chemistry, University of Liverpool, Crown Street, LiverpoolL69 7ZD, United Kingdom
| | - Christopher J. Kiely
- Department of Materials Science and Engineering, Lehigh University, 5 East Packer Avenue, Bethlehem, Pennsylvania18015, United States
| | - Graham J. Hutchings
- Max Planck−Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, CardiffCF10 3AT, United Kingdom
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9
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Kuzhanthaivelan S, Sunitha S, Rajakumar B. Computational investigation of thermochemistry and kinetics of the reaction between n-butyl peroxy and hydroperoxyl radicals. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.140191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Onel L, Brennan A, Østerstro M FF, Cooke E, Whalley L, Seakins PW, Heard DE. Kinetics and Product Branching Ratio Study of the CH 3O 2 Self-Reaction in the Highly Instrumented Reactor for Atmospheric Chemistry. J Phys Chem A 2022; 126:7639-7649. [PMID: 36227778 PMCID: PMC9620170 DOI: 10.1021/acs.jpca.2c04968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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The fluorescence assay by gas expansion (FAGE) method
for the measurement
of the methyl peroxy radical (CH3O2) using the
conversion of CH3O2 into methoxy radicals (CH3O) by excess NO, followed by the detection of CH3O, has been used to study the kinetics of the self-reaction of CH3O2. Fourier transform infrared (FTIR) spectroscopy
has been employed to determine the products methanol and formaldehyde
of the self-reaction. The kinetics and product studies were performed
in the Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC)
in the temperature range 268–344 K at 1000 mbar of air. The
product measurements were used to determine the branching ratio of
the reaction channel forming methoxy radicals, rCH3O. A value of 0.34 ± 0.05 (errors at 2σ level)
was determined for rCH3O at 295 K. The
temperature dependence of rCH3O can be
parametrized as rCH3O = 1/{1 + [exp(600
± 85)/T]/(3.9 ± 1.1)}. An overall rate
coefficient of the self-reaction of (2.0 ± 0.9) × 10–13 cm3 molecule–1 s–1 at 295 K was obtained by the kinetic analysis of
the observed second-order decays of CH3O2. The
temperature dependence of the overall rate coefficient can be characterized
by koverall = (9.1 ± 5.3) ×
10–14 × exp((252 ± 174)/T) cm3 molecule–1 s–1. The found values of koverall in the
range 268–344 K are ∼40% lower than the values calculated
using the recommendations of the Jet Propulsion Laboratory and IUPAC,
which are based on the previous studies, all of them utilizing time-resolved
UV–absorption spectroscopy to monitor CH3O2. A modeling study using a complex chemical mechanism to describe
the reaction system showed that unaccounted secondary chemistry involving
Cl species increased the values of koverall in the previous studies using flash photolysis to initiate the chemistry.
The overestimation of the koverall values
by the kinetic studies using molecular modulation to generate CH3O2 can be rationalized by a combination of underestimated
optical absorbance of CH3O2 and unaccounted
CH3O2 losses to the walls of the reaction cells
employed.
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Affiliation(s)
- Lavinia Onel
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Alexander Brennan
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | | | - Ellie Cooke
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Lisa Whalley
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom.,National Centre for Atmospheric Science, University of Leeds, LS2 9JT, United Kingdom
| | - Paul W Seakins
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Dwayne E Heard
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
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11
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Day DA, Fry JL, Kang HG, Krechmer JE, Ayres BR, Keehan NI, Thompson SL, Hu W, Campuzano-Jost P, Schroder JC, Stark H, DeVault MP, Ziemann PJ, Zarzana KJ, Wild RJ, Dubè WP, Brown SS, Jimenez JL. Secondary Organic Aerosol Mass Yields from NO 3 Oxidation of α-Pinene and Δ-Carene: Effect of RO 2 Radical Fate. J Phys Chem A 2022; 126:7309-7330. [PMID: 36170568 DOI: 10.1021/acs.jpca.2c04419] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dark chamber experiments were conducted to study the SOA formed from the oxidation of α-pinene and Δ-carene under different peroxy radical (RO2) fate regimes: RO2 + NO3, RO2 + RO2, and RO2 + HO2. SOA mass yields from α-pinene oxidation were <1 to ∼25% and strongly dependent on available OA mass up to ∼100 μg m-3. The strong yield dependence of α-pinene oxidation is driven by absorptive partitioning to OA and not by available surface area for condensation. Yields from Δ-carene + NO3 were consistently higher, ranging from ∼10-50% with some dependence on OA for <25 μg m-3. Explicit kinetic modeling including vapor wall losses was conducted to enable comparisons across VOC precursors and RO2 fate regimes and to determine atmospherically relevant yields. Furthermore, SOA yields were similar for each monoterpene across the nominal RO2 + NO3, RO2 + RO2, or RO2 + HO2 regimes; thus, the volatility basis sets (VBS) constructed were independent of the chemical regime. Elemental O/C ratios of ∼0.4-0.6 and nitrate/organic mass ratios of ∼0.15 were observed in the particle phase for both monoterpenes in all regimes, using aerosol mass spectrometer (AMS) measurements. An empirical relationship for estimating particle density using AMS-derived elemental ratios, previously reported in the literature for non-nitrate containing OA, was successfully adapted to organic nitrate-rich SOA. Observations from an NO3- chemical ionization mass spectrometer (NO3-CIMS) suggest that Δ-carene more readily forms low-volatility gas-phase highly oxygenated molecules (HOMs) than α-pinene, which primarily forms volatile and semivolatile species, when reacted with NO3, regardless of RO2 regime. The similar Δ-carene SOA yields across regimes, high O/C ratios, and presence of HOMs, suggest that unimolecular and multistep processes such as alkoxy radical isomerization and decomposition may play a role in the formation of SOA from Δ-carene + NO3. The scarcity of peroxide functional groups (on average, 14% of C10 groups carried a peroxide functional group in one test experiment in the RO2 + RO2 regime) appears to rule out a major role for autoxidation and organic peroxide (ROOH, ROOR) formation. The consistently substantially lower SOA yields observed for α-pinene + NO3 suggest such pathways are less available for this precursor. The marked and robust regime-independent difference in SOA yield from two different precursor monoterpenes suggests that in order to accurately model SOA production in forested regions the chemical mechanism must feature some distinction among different monoterpenes.
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Affiliation(s)
- Douglas A Day
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Juliane L Fry
- Department of Chemistry, Reed College, Portland, Oregon 97202, United States
| | - Hyun Gu Kang
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Department of Chemistry, Reed College, Portland, Oregon 97202, United States
| | - Jordan E Krechmer
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Benjamin R Ayres
- Department of Chemistry, Reed College, Portland, Oregon 97202, United States
| | - Natalie I Keehan
- Department of Chemistry, Reed College, Portland, Oregon 97202, United States
| | - Samantha L Thompson
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Weiwei Hu
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Pedro Campuzano-Jost
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Jason C Schroder
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Harald Stark
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Aerodyne Research Inc., Billerica, Massachusetts 01821, United States
| | - Marla P DeVault
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Paul J Ziemann
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Kyle J Zarzana
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Chemical Sciences Laboratory, National Oceanic & Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Robert J Wild
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Chemical Sciences Laboratory, National Oceanic & Atmospheric Administration, Boulder, Colorado 80305, United States
| | - William P Dubè
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Chemical Sciences Laboratory, National Oceanic & Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Steven S Brown
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Chemical Sciences Laboratory, National Oceanic & Atmospheric Administration, Boulder, Colorado 80305, United States
| | - Jose L Jimenez
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
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12
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Salo VT, Valiev R, Lehtola S, Kurtén T. Gas-Phase Peroxyl Radical Recombination Reactions: A Computational Study of Formation and Decomposition of Tetroxides. J Phys Chem A 2022; 126:4046-4056. [PMID: 35709531 PMCID: PMC9251773 DOI: 10.1021/acs.jpca.2c01321] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
The recombination
(“dimerization”) of peroxyl radicals
(RO2•) is one of the pathways suggested in the literature
for the formation of peroxides (ROOR′, often referred to as
dimers or accretion products in the literature) in the atmosphere.
It is generally accepted that these dimers play a major role in the
first steps of the formation of submicron aerosol particles. However,
the precise reaction pathways and energetics of RO2•
+ R′O2• reactions are still unknown. In this
work, we have studied the formation of tetroxide intermediates (RO4R′): their formation from two peroxyl radicals and
their decomposition to triplet molecular oxygen (3O2) and a triplet pair of alkoxyl radicals (RO•). We
demonstrate this mechanism for several atmospherically relevant primary
and secondary peroxyl radicals. The potential energy surface corresponds
to an overall singlet state. The subsequent reaction channels of the
alkoxyl radicals include, but are not limited to, their dimerization
into ROOR′. Our work considers the multiconfigurational character
of the tetroxides and the intermediate phases of the reaction, leading
to reliable mechanistic insights for the formation and decomposition
of the tetroxides. Despite substantial uncertainties in the computed
energetics, our results demonstrate that the barrier heights along
the reaction path are invariably small for these systems. This suggests
that the reaction mechanism, previously validated at a multireference
level only for methyl peroxyl radicals, is a plausible pathway for
the formation of aerosol-relevant larger peroxides in the atmosphere.
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Affiliation(s)
- Vili-Taneli Salo
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FI-00014, Finland
| | - Rashid Valiev
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FI-00014, Finland
| | - Susi Lehtola
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FI-00014, Finland.,Molecular Sciences Software Institute, Blacksburg, Virginia 24061, United States
| | - Theo Kurtén
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FI-00014, Finland
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13
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Liu Y, Li J. Permutation-Invariant-Polynomial Neural-Network-Based Δ-Machine Learning Approach: A Case for the HO 2 Self-Reaction and Its Dynamics Study. J Phys Chem Lett 2022; 13:4729-4738. [PMID: 35609295 DOI: 10.1021/acs.jpclett.2c01064] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Δ-machine learning, or the hierarchical construction scheme, is a highly cost-effective method, as only a small number of high-level ab initio energies are required to improve a potential energy surface (PES) fit to a large number of low-level points. However, there is no efficient and systematic way to select as few points as possible from the low-level data set. We here propose a permutation-invariant-polynomial neural-network (PIP-NN)-based Δ-machine learning approach to construct full-dimensional accurate PESs of complicated reactions efficiently. Particularly, the high flexibility of the NN is exploited to efficiently sample points from the low-level data set. This approach is applied to the challenging case of a HO2 self-reaction with a large configuration space. Only 14% of the DFT data set is used to successfully bring a newly fitted DFT PES to the UCCSD(T)-F12a/AVTZ quality. Then, the quasiclassical trajectory (QCT) calculations are performed to study its dynamics, particularly the mode specificity.
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Affiliation(s)
- Yang Liu
- School of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China
| | - Jun Li
- School of Chemistry and Chemical Engineering & Chongqing Key Laboratory of Theoretical and Computational Chemistry, Chongqing University, Chongqing 401331, China
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14
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Li G, Lu Y, Glarborg P. Oxidation Kinetics of Methane and Methane/Methanol Mixtures in Supercritical Water. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.1c04524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guoxing Li
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, PR China
| | - Youjun Lu
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049, PR China
| | - Peter Glarborg
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Lyngby 2800, Denmark
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15
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Synthesis and Characterization of Atmospherically Relevant Hydroxy Hydroperoxides. ATMOSPHERE 2022. [DOI: 10.3390/atmos13040507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Hydroxy hydroperoxides are formed upon OH oxidation of volatile organic compounds in the atmosphere and may contribute to secondary organic aerosol growth and aqueous phase chemistry after phase transfer to particles. Although the detection methods for oxidized volatile organic compounds improved much over the past decades, the limited availability of synthetic standards for atmospherically relevant hydroxy hydroperoxides prevented comprehensive investigations for the most part. Here, we present a straightforward improved synthetic access to isoprene-derived hydroxy hydroperoxides, i.e., 1,2-ISOPOOH and 4,3-ISOPOOH. Furthermore, we present the first successful synthesis of an α-pinene derived hydroxy hydroperoxide. All products were identified by 1H, 13C NMR spectroscopy for structure elucidation, additional 2D NMR experiments were performed. Furthermore, gas-phase FTIR- and UV/VIS spectra are presented for the first time. Using the measured absorption cross section, the atmospheric photolysis rate of up to 2.1 × 10−3 s−1 was calculated for 1,2-ISOPOOH. Moreover, we present the investigation of synthesized hydroxy hydroperoxides in an aerosol chamber study by online MS techniques, namely PTR-ToFMS and (NO3−)-CI-APi-ToFMS. Fragmentation patterns recorded during these investigations are presented as well. For the (NO3−)-CI-APi-ToFMS, a calibration factor for 1,2-ISOPOOH was calculated as 4.44 × 10−5 ncps·ppbv−1 and a LOD (3σ, 1 min average) = 0.70 ppbv.
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16
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Spectroscopic characterization of two peroxyl radicals during the O 2-oxidation of the methylthio radical. Commun Chem 2022; 5:19. [PMID: 36697894 PMCID: PMC9814412 DOI: 10.1038/s42004-022-00637-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 01/26/2022] [Indexed: 01/28/2023] Open
Abstract
The atmospheric oxidation of dimethyl sulfide (DMS) yields sulfuric acid and methane sulfonic acid (MSA), which are key precursors to new particles formed via homogeneous nucleation and further cluster growth in air masses. Comprehensive experimental and theoretical studies have suggested that the oxidation of DMS involves the formation of the methylthio radical (CH3S•), followed by its O2-oxidation reaction via the intermediacy of free radicals CH3SOx• (x = 1-4). Therefore, capturing these transient radicals and disclosing their reactivity are of vital importance in understanding the complex mechanism. Here, we report an optimized method for efficient gas-phase generation of CH3S• through flash pyrolysis of S-nitrosothiol CH3SNO, enabling us to study the O2-oxidation of CH3S• by combining matrix-isolation spectroscopy (IR and UV-vis) with quantum chemical computations at the CCSD(T)/aug-cc-pV(X + d)Z (X = D and T) level of theory. As the key intermediate for the initial oxidation of CH3S•, the peroxyl radical CH3SOO• forms by reacting with O2. Upon irradiation at 830 nm, CH3SOO• undergoes isomerization to the sulfonyl radical CH3SO2• in cryogenic matrixes (Ar, Ne, and N2), and the latter can further combine with O2 to yield another peroxyl radical CH3S(O)2OO• upon further irradiation at 440 nm. Subsequent UV-light irradiation (266 nm) causes dissociation of CH3S(O)2OO• to CH3SO2•, CH2O, SO2, and SO3. The IR spectroscopic identification of the two peroxyl radicals CH3SOO• and CH3S(O)2OO• is also supported by 18O- and 13C-isotope labeling experiments.
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17
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Nguyen TL, Perera A, Peeters J. High-accuracy first-principles-based rate coefficients for the reaction of OH and CH 3OOH. Phys Chem Chem Phys 2022; 24:26684-26691. [DOI: 10.1039/d2cp03919b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The ˙OH-initiated oxidation of methyl hydroperoxide was theoretically characterized using high-accuracy composite amHEAT-345(Q) coupled-cluster calculations followed by a two-dimensional E,J resolved master equation analysis.
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Affiliation(s)
- Thanh Lam Nguyen
- Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, FL, 32611, USA
| | - Ajith Perera
- Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, FL, 32611, USA
| | - Jozef Peeters
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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18
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Dong P, Chen Z, Qin X, Gong Y. Water Significantly Changes the Ring-Cleavage Process During Aqueous Photooxidation of Toluene. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16316-16325. [PMID: 34877862 DOI: 10.1021/acs.est.1c04770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
As a major constituent of aromatic compounds, toluene exists widely in environmental aqueous phases. This research investigated the aqueous-phase OH oxidation of toluene to determine how liquid water changes the radical chemistry of ring-cleavage pathways. Results show that ring-cleavage pathways through the C7 bicyclic peroxy radical (BPR) account for about 70% of total aqueous-phase oxidation pathways, which is similar to that in the gas-phase oxidation. However, detailed ring-cleavage pathways in the aqueous phase change significantly compared with those in the gas phase as shown by the decreased production of glyoxal and methylglyoxal and the enhanced production of formic acid and acetic acid as primary products, which can be attributed to the presence of liquid water. Water facilitates the formation of the BPR whose structure is different from that in the gas-phase oxidation and results in different ring-cleavage pathways through hydrogen-shift reactions. Furthermore, water helps the hydration of acyl radicals formed by the BPR to produce organic acids. With the suggested ring-cleavage mechanisms, a box model can simulate aqueous-phase product distributions better than that with the classical ring-cleavage mechanisms. Given the influence of water on reaction mechanisms, aqueous-phase oxidation of hydrophobic organic compounds may be more important than previously assumed.
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Affiliation(s)
- Ping Dong
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zhongming Chen
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Xuan Qin
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yiwei Gong
- State Key Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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19
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Wen Z, Lin X, Tang X, Long B, Wang C, Zhang C, Fittschen C, Yang J, Gu X, Zhang W. Vacuum ultraviolet photochemistry of the conformers of the ethyl peroxy radical. Phys Chem Chem Phys 2021; 23:22096-22102. [PMID: 34580690 DOI: 10.1039/d1cp02655k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We study the conformers of the ethyl peroxy radical (C2H5O2), the simplest peroxy radical having more than one conformer, by combining synchrotron radiation vacuum ultraviolet (VUV) photoionization mass spectrometry with theoretical calculations. The ethyl peroxy radical is formed in a microwave discharge flow tube through the reaction of the ethyl radical (C2H5) with oxygen molecules, where C2H5 is generated via the hydrogen-abstraction reaction of ethane with fluorine atoms. Two kinds of C2H5+, originating from photoionization of C2H5 and from dissociative photoionization of C2H5O2, whose cation is not stable, have been identified and separated in photoionization mass spectra. The photoionization spectrum corresponding to C2H5O2 is obtained and assigned with Franck-Condon calculations. The present findings show that the gauche conformer (G-C2H5O2) of C2H5O2 has favorable Franck-Condon factors in the ionization transitions, whereas the contribution of the trans conformer (T-C2H5O2) to the photoionization spectrum is minor or negligible due to its large geometric changes in the photoionization process. Moreover, the reason for the instability of C2H5O2+ and its detailed dissociation mechanisms have been unraveled with the aid of the calculated potential energy curves.
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Affiliation(s)
- Zuoying Wen
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Bo Long
- School of Materials Science and Engineering, Guizhou Minzu University, Guiyang, 550025 Guizhou, China
| | - Chengcheng Wang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Cuihong Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Christa Fittschen
- University Lille, CNRS, UMR 8522, PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Jiuzhong Yang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, 230029 Anhui, China
| | - Xuejun Gu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
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20
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Larin IK, Belyakova TI, Messineva NA, Spassky AI, Trofimova EM. Photolysis of C2H2F2Br2 Mixture with O2 in the Oxygen Pressure Range 1–3.5 Torr. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2021. [DOI: 10.1134/s1990793121050195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Link MF, Farmer DK, Berg T, Flocke F, Ravishankara AR. Measuring Photodissociation Product Quantum Yields Using Chemical Ionization Mass Spectrometry: A Case Study with Ketones. J Phys Chem A 2021; 125:6836-6844. [PMID: 34324344 DOI: 10.1021/acs.jpca.1c03140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Measurements of photolysis quantum yields are challenging because of the difficulties in measuring the first-generation photodissociation products, interference from other products or contaminants, sufficient photon fluxes and/or low absorption cross sections of the photolyte to make detectable amounts of products, and quantification of the photon flux. In the case of acetone (and other atmospherically relevant ketones) the uncertainty in the photolysis quantum yield creates uncertainty in the calculated OH radical and acyl peroxy nitrate production in the atmosphere. We present a new method for determining photodissociation product quantum yields by measuring acyl peroxy radicals (RC(O)O2) produced in the photolysis of ketones in air using chemical ionization mass spectrometry (CIMS). We show good agreement of our CIMS method with previously published quantum yields of the acyl radical from photolysis of biacetyl and methyl ethyl ketone (MEK) at 254 nm. Additionally, we highlight the capabilities of this CIMS method through the measurement of photolysis branching ratios for MEK. We suggest future applications of CIMS (in the laboratory and field) to measure RC(O)O2 and associated photolysis processes.
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Affiliation(s)
- Michael F Link
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Delphine K Farmer
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Tyson Berg
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Frank Flocke
- National Center for Atmospheric Research, Boulder, Colorado 80301, United States
| | - A R Ravishankara
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States.,Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado 80523, United States
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22
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Absolute Absorption Cross-Section of the Ã←X˜ Electronic Transition of the Ethyl Peroxy Radical and Rate Constant of Its Cross Reaction with HO2. PHOTONICS 2021. [DOI: 10.3390/photonics8080296] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The absolute absorption cross-section of the ethyl peroxy radical C2H5O2 in the Ã←X˜ electronic transition with the peak wavelength at 7596 cm−1 has been determined by the method of dual wavelengths time resolved continuous wave cavity ring down spectroscopy. C2H5O2 radicals were generated from pulsed 351 nm photolysis of C2H6/Cl2 mixture in presence of 100 Torr O2 at T = 295 K. C2H5O2 radicals were detected on one of the CRDS paths. Two methods have been applied for the determination of the C2H5O2 absorption cross-section: (i) based on Cl-atoms being converted alternatively to either C2H5O2 by adding C2H6 or to hydro peroxy radicals, HO2, by adding CH3OH to the mixture, whereby HO2 was reliably quantified on the second CRDS path in the 2ν1 vibrational overtone at 6638.2 cm−1 (ii) based on the reaction of C2H5O2 with HO2, measured under either excess HO2 or under excess C2H5O2 concentration. Both methods lead to the same peak absorption cross-section for C2H5O2 at 7596 cm−1 of σ = (1.0 ± 0.2) × 10−20 cm2. The rate constant for the cross reaction between of C2H5O2 and HO2 has been measured to be (6.2 ± 1.5) × 10−12 cm3 molecule−1 s−1.
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23
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Liu Y, Shen H, Mu J, Li H, Chen T, Yang J, Jiang Y, Zhu Y, Meng H, Dong C, Wang W, Xue L. Formation of peroxyacetyl nitrate (PAN) and its impact on ozone production in the coastal atmosphere of Qingdao, North China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 778:146265. [PMID: 33714821 DOI: 10.1016/j.scitotenv.2021.146265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/08/2021] [Accepted: 02/28/2021] [Indexed: 06/12/2023]
Abstract
Peroxyacetyl nitrate (PAN), acting as a relatively long-lived reservoir for both NOx and radicals, plays a crucial role in ozone (O3) formation in the troposphere. However, its quantitative impacts on radical concentrations and O3 production were rarely studied in the coastal atmosphere. In this study, ambient concentrations of PAN, O3, and related species were simultaneously measured from October 5 to November 10, 2018 (autumn), and July 14 to August 24, 2019 (summer) at a rural coastal site in Qingdao, North China. The formation mechanism of PAN and its impact on in-situ O3 production were explored with an observation-based chemical box model. Photochemical formation of PAN and O3 was controlled by both NOx and VOCs, and acetaldehyde and methylglyoxal were the main contributors to PAN formation. However, the sensitivities of PAN to precursors were larger than that of O3 in autumn while smaller in summer, which was mainly caused by the rapid decomposition of PAN at high temperatures. Zero-out sensitivity simulation showed that PAN could either promote or inhibit the in-situ O3 formation by affecting the radical chemistry. It tended to suppress O3 production by competing with precursors and terminating radical chain reactions under low-NOx and low-ROx circumstances but enhanced O3 production by supplying RO2 radicals under conditions with sufficient NOx. This study provides some new complementary insights into the formation mechanism of PAN and its impacts on O3 production, and has implications for the formulation of control policy to mitigate regional photochemical pollution in northern China.
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Affiliation(s)
- Yuhong Liu
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Hengqing Shen
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China.
| | - Jiangshan Mu
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Hongyong Li
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Tianshu Chen
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Juan Yang
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Ying Jiang
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Yujiao Zhu
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - He Meng
- Qingdao Eco-environment Monitoring Center of Shandong Province, Qingdao, Shandong 266003, China
| | - Can Dong
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Wenxing Wang
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China
| | - Likun Xue
- Environment Research Institute, Shandong University, Qingdao, Shandong 266237, China; Ji'nan Eco-Environmental Monitoring Center of Shandong Province, Ji'nan, Shandong 250000, China.
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24
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Zuraski K, Hui AO, Grieman FJ, Darby E, Møller KH, Winiberg FAF, Percival CJ, Smarte MD, Okumura M, Kjaergaard HG, Sander SP. Acetonyl Peroxy and Hydro Peroxy Self- and Cross-Reactions: Kinetics, Mechanism, and Chaperone Enhancement from the Perspective of the Hydroxyl Radical Product. J Phys Chem A 2020; 124:8128-8143. [PMID: 32852951 DOI: 10.1021/acs.jpca.0c06220] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pulsed laser photolysis coupled with infrared (IR) wavelength modulation spectroscopy and ultraviolet (UV) absorption spectroscopy was used to study the kinetics and branching fractions for the acetonyl peroxy (CH3C(O)CH2O2) self-reaction and its reaction with hydro peroxy (HO2) at a temperature of 298 K and pressure of 100 Torr. Near-IR and mid-IR lasers simultaneously monitored HO2 and hydroxyl, OH, respectively, while UV absorption measurements monitored the CH3C(O)CH2O2 concentrations. The overall rate constant for the reaction between CH3C(O)CH2O2 and HO2 was found to be (5.5 ± 0.5) × 10-12 cm3 molecule-1 s-1, and the branching fraction for OH yield from this reaction was directly measured as 0.30 ± 0.04. The CH3C(O)CH2O2 self-reaction rate constant was measured to be (4.8 ± 0.8) × 10-12 cm3 molecule-1 s-1, and the branching fraction for alkoxy formation was inferred from secondary chemistry as 0.33 ± 0.13. An increase in the rate of the HO2 self-reaction was also observed as a function of acetone (CH3C(O)CH3) concentration which is interpreted as a chaperone effect, resulting from hydrogen-bond complexation between HO2 and CH3C(O)CH3. The chaperone enhancement coefficient for CH3C(O)CH3 was determined to be kA″ = (4.0 ± 0.2) × 10-29 cm6 molecule-2 s-1, and the equilibrium constant for HO2·CH3C(O)CH3 complex formation was found to be Kc(R14) = (2.0 ± 0.89) × 10-18 cm3 molecule-1; from these values, the rate constant for the HO2 + HO2·CH3C(O)CH3 reaction was estimated to be (2 ± 1) × 10-11 cm3 molecule-1 s-1. Results from UV absorption cross-section measurements of CH3C(O)CH2O2 and prompt OH radical yields arising from possible oxidation of the CH3C(O)CH3-derived alkyl radical are also discussed. Using theoretical methods, no likely pathways for the observed prompt OH radical formation have been found and the prompt OH radical yields thus remain unexplained.
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Affiliation(s)
- Kristen Zuraski
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Aileen O Hui
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Fred J Grieman
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,Seaver Chemistry Laboratory, Pomona College, Claremont, California 91711, United States
| | - Emily Darby
- Seaver Chemistry Laboratory, Pomona College, Claremont, California 91711, United States
| | - Kristian H Møller
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Frank A F Winiberg
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Carl J Percival
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Matthew D Smarte
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Mitchio Okumura
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Henrik G Kjaergaard
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø DK-2100, Denmark
| | - Stanley P Sander
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
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25
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Liu C, Wang H, Ma Q, Ma J, Wang Z, Liang L, Xu W, Zhang G, Zhang X, Wang T, He H. Efficient Conversion of NO to NO 2 on SO 2-Aged MgO under Atmospheric Conditions. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:11848-11856. [PMID: 32885975 DOI: 10.1021/acs.est.0c05071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The NO-NO2 cycle determines the formation of O3 and hence plays a critical role in the oxidizing capacity of troposphere. Traditional view concluded that the heterogeneous oxidation of NO to NO2 was negligible due to the weak reactivity of NO on aerosols, compared to the homogeneous oxidation process. However, the results here reported for the first time that SO2 can greatly promote the heterogeneous transformation of NO into NO2 and HONO on MgO particles under ambient conditions. The uptake coefficients of NO were increased by 2-3 orders of magnitudes on SO2-aged MgO, compared to the fresh sample. Based on spectroscopic characterization and density functional theory (DFT) calculations, the active sites for the adsorption and oxidation of NO were determined to be sulfates, where an intermediate [SO4-NO] complex was formed during the adsorption. The decomposition of this species led to the formation of NO2 and the change of sulfate configuration. The formed NO2 could further react with surface sulfite to form HONO and sulfate. The conversion of NO to NO2 and HONO on the SO2-aged MgO surface under ambient conditions contributes a new formation pathway of NO2 and HONO and could be quite helpful for understanding the source of atmospheric oxidizing capacity as well as the formation of air pollution complexes in polluted regions such as the northern China.
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Affiliation(s)
- Chang Liu
- State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of China Meteorological Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China
| | - Honghong Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Qingxin Ma
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinzhu Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhe Wang
- Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Kowloon, 999077, Hong Kong, China
| | - Linlin Liang
- State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of China Meteorological Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Wanyun Xu
- State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of China Meteorological Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Gen Zhang
- State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of China Meteorological Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Xiaoye Zhang
- State Key Laboratory of Severe Weather & Key Laboratory of Atmospheric Chemistry of China Meteorological Administration, Chinese Academy of Meteorological Sciences, Beijing 100081, China
- Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Tao Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong 999077, China
| | - Hong He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Urban Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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26
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Sensitivity of Simulated PM2.5 Concentrations over Northeast Asia to Different Secondary Organic Aerosol Modules during the KORUS-AQ Campaign. ATMOSPHERE 2020. [DOI: 10.3390/atmos11091004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A numerical sensitivity study on secondary organic aerosol formation has been carried out by employing the WRF-Chem (Weather Research and Forecasting model coupled with Chemistry). Two secondary organic aerosol formation modules, the Modal Aerosol Dynamics model for Europe/Volatility Basis Set (MADE/VBS) and the Modal Aerosol Dynamics model for Europe/Secondary Organic Aerosol Model (MADE/SORGAM) were employed in the WRF-Chem model, and surface PM2.5 (particulate matter less than 2.5 μm in size) mass concentration and the composition of its relevant chemical sources, i.e., SO42−, NO3−, NH4+, and organic carbon (OC) were simulated during the Korea-United States Air Quality (KORUS-AQ) campaign period (1 May to 12 June 2016). We classified the KORUS-AQ period into two cases, the stagnant period (16–21 May) which was dominated by local emission and the long-range transport period (25–31 May) which was affected by transport from the leeward direction, and focused on the differences in OC secondary aerosol formation between two modules over Northeast Asia. The simulated surface PM2.5 chemical components via the two modules showed the largest systematic biases in surface OC, with a mean bias of 4.5 μg m−3, and the second largest in SO42− abundance of 2.2 μg m−3 over Seoul. Compared with surface observations at two ground sites located near the western coastal Korean Peninsula, MADE/VBS exhibited the overpredictions in OC by 170–180%, whereas MADE/SORGAM showed underpredictions by 49–65%. OC and sulfate via MADE/VBS were simulated to be much higher than that simulated by MADE/SORGAM by a factor of 2.8–3.5 and 1.5–1.9, respectively. Model verification against KORUS-AQ aircraft measurements also showed large discrepancies in simulated non-surface OC between the two modules by a factor of five, with higher OC by MADE/VBS and lower IC by MADE/SORGAM, whereas much closer MADE/VBS simulations to the KORUS-AQ aircraft measurements were found. On the basis of the aircraft measurements, the aggregated bias (sum of four components) for PM2.5 mass concentrations from the MADE/VBS module indicated that the simulation was much closer to the measurements, nevertheless more elaborate analysis on the surface OC simulation performance would be needed to improve the ground results. Our findings show that significant inconsistencies are present in the secondary organic aerosol formation simulations, suggesting that PM2.5 forecasts should be considered with great caution, as well as in the context of policymaking in the Northeast Asia region.
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27
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Reaction of CH2Cl radical with O2 in solid para-hydrogen: Infrared spectrum of gauche-CH2ClOO radical. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Valiev RR, Kurten T. Is either direct photolysis or photocatalysed H-shift of peroxyl radicals a competitive pathway in the troposphere? ROYAL SOCIETY OPEN SCIENCE 2020; 7:200521. [PMID: 33047020 PMCID: PMC7540759 DOI: 10.1098/rsos.200521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Peroxyl radicals (RO O . ) are key intermediates in atmospheric chemistry, with relatively long lifetimes compared to most other radical species. In this study, we use multireference quantum chemical methods to investigate whether photolysis can compete with well-established RO O . sink reactions. We assume that the photolysis channel is always RO O . + hν => RO + O(3P). Our results show that the maximal value of the cross-section for this channel is σ = 1.3 × 10-18 cm2 at 240 nm for five atmospherically representative peroxyl radicals: CH3O O . , C(O)HCH2O O . , CH3CH2O O . , HC(O)O O . and CH3C(O)O O . . These values agree with experiments to within a factor of 2. The rate constant of photolysis in the troposphere is around 10-5 s-1 for all five RO O . . As the lifetime of peroxyl radicals in the troposphere is typically less than 100 s, photolysis is thus not a competitive process. Furthermore, we investigate whether or not electronic excitation to the first excited state (D1) by infrared radiation can facilitate various H-shift reactions, leading, for example, in the case of CH3O O . to formation of O . H and CH2O or HO O . and CH2 products. While the activation barriers for H-shifts in the D1 state may be lower than in the ground state (D0), we find that H-shifts are unlikely to be competitive with decay back to the D0 state through internal conversion, as this has a rate of the order of 1013 s-1 for all studied systems.
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Affiliation(s)
- Rashid R. Valiev
- Department of Chemistry, University of Helsinki, PO Box 55 (A.I. Virtanens Plats 1), 00014 Helsinki, Finland
- Tomsk State University, 36, Lenin Avenue, 634050 Tomsk, Russia
| | - Theo Kurten
- Department of Chemistry, University of Helsinki, PO Box 55 (A.I. Virtanens Plats 1), 00014 Helsinki, Finland
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki 00014, Finland
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29
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Zhang Y, He B, Sun Y. Theoretical investigations on •Cl-initiated atmospheric degradation of CHX2O2 (X = F, Cl). J Fluor Chem 2020. [DOI: 10.1016/j.jfluchem.2020.109501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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30
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Weidman JD, Turney JM, Schaefer HF. Energetics and mechanisms for the acetonyl radical + O 2 reaction: An important system for atmospheric and combustion chemistry. J Chem Phys 2020; 152:114301. [PMID: 32199416 DOI: 10.1063/1.5141859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The acetonyl radical (•CH2COCH3) is relevant to atmospheric and combustion chemistry due to its prevalence in many important reaction mechanisms. One such reaction mechanism is the decomposition of Criegee intermediates in the atmosphere that can produce acetonyl radical and OH. In order to understand the fate of the acetonyl radical in these environments and to create more accurate kinetics models, we have examined the reaction system of the acetonyl radical with O2 using highly reliable theoretical methods. Structures were optimized using coupled cluster theory with singles, doubles, and perturbative triples [CCSD(T)] with an atomic natural orbital (ANO0) basis set. Energetics were computed to chemical accuracy using the focal point approach involving perturbative treatment of quadruple excitations [CCSDT(Q)] and basis sets as large as cc-pV5Z. The addition of O2 to the acetonyl radical produces the acetonylperoxy radical, and multireference computations on this reaction suggest it to be barrierless. No submerged pathways were found for the unimolecular isomerization of the acetonylperoxy radical. Besides dissociation to reactants, the lowest energy pathway available for the acetonylperoxy radical is a 1-5 H shift from the methyl group to the peroxy group through a transition state that is 3.3 kcal mol-1 higher in energy than acetonyl radical + O2. The ultimate products from this pathway are the enol tautomer of the acetonyl radical along with O2. Multiple pathways that lead to OH formation are considered; however, all of these pathways are predicted to be energetically inaccessible, except at high temperatures.
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Affiliation(s)
- Jared D Weidman
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Justin M Turney
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, USA
| | - Henry F Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, USA
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31
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Tang X, Gu X, Lin X, Zhang W, Garcia GA, Fittschen C, Loison JC, Voronova K, Sztáray B, Nahon L. Vacuum ultraviolet photodynamics of the methyl peroxy radical studied by double imaging photoelectron photoion coincidences. J Chem Phys 2020; 152:104301. [DOI: 10.1063/5.0002109] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xuejun Gu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
| | - Christa Fittschen
- University Lille, CNRS, UMR 8522, PC2A – Physicochimie des Processus de Combustion et de l’Atmosphère, F-59000 Lille, France
| | - Jean-Christophe Loison
- ISM, Université Bordeaux 1, CNRS, 351 cours de la Libération, 33405 Talence Cedex, France
| | - Krisztina Voronova
- Department of Chemistry, University of Nevada, Reno, Reno, Nevada 89557-0216, USA
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, USA
| | - Laurent Nahon
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
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32
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Lu B, Song C, Liu J, Trabelsi T, Francisco JS, Wang L, Zeng X. Dihalogenated Methylperoxy Radicals: Spectroscopic Characterization and Photodecomposition by Release of HO .. Chemistry 2020; 26:2817-2820. [PMID: 31899574 DOI: 10.1002/chem.201905858] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Indexed: 11/08/2022]
Abstract
Two atmospherically relevant dihalogenated methylperoxy radicals CHX2 OO. (X=F and Cl) have been generated through O2 -oxidation of the corresponding alkyl radicals CHX2 . in the gas phase. The IR spectroscopic characterization of both radicals in cryogenic Ar- and N2 -matrices (15 K) is supported by 18 O-labeling and ab initio calculations at the UCCSD(T)/aug-cc-pVTZ level. Upon 266 nm laser irradiation, both radicals decompose mainly by releasing hydroxyl radicals (→HO. +X2 CO) via the intermediacy of intriguing α-hydroperoxyalkyl radicals (. CX2 OOH), implying that the photooxidation of dihalogenated hydrocarbons might serve as important sources of HO. radicals in the atmosphere.
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Affiliation(s)
- Bo Lu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P. R. China
| | - Chao Song
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P. R. China
| | - Jie Liu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P. R. China
| | - Tarek Trabelsi
- Department of Earth and Environmental Science and Department of, Chemistry, University of Pennsylvania, Pennsylvania, 19104, USA
| | - Joseph S Francisco
- Department of Earth and Environmental Science and Department of, Chemistry, University of Pennsylvania, Pennsylvania, 19104, USA
| | - Lina Wang
- Department of Chemistry, Fudan University, Shanghai, 200433, P. R. China
| | - Xiaoqing Zeng
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P. R. China.,Department of Chemistry, Fudan University, Shanghai, 200433, P. R. China
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33
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Tang X, Lin X, Garcia GA, Loison JC, Gouid Z, Abdallah HH, Fittschen C, Hochlaf M, Gu X, Zhang W, Nahon L. Identifying isomers of peroxy radicals in the gas phase: 1-C3H7O2vs. 2-C3H7O2. Chem Commun (Camb) 2020; 56:15525-15528. [DOI: 10.1039/d0cc06516a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The two isomers of propylperoxy radical 1-C3H7O2 and 2-C3H7O2, together with their rotamers, are individually identified and assigned.
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Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | | | | | - Zied Gouid
- Université Gustave Eiffel
- COSYS/LISIS
- Champs sur Marne
- France
- Laboratoire de Caractérisations, Applications et Modélisations des Matériaux
| | - Hassan H. Abdallah
- Department of Chemistry
- College of Education
- Salahaddin University-Erbil
- 44002 Erbil
- Iraq
| | - Christa Fittschen
- University Lille
- CNRS
- UMR 8522
- PC2A – Physicochimie des Processus de Combustion et de l’Atmosphère
- F-59000 Lille
| | - Majdi Hochlaf
- Université Gustave Eiffel
- COSYS/LISIS
- Champs sur Marne
- France
| | - Xuejun Gu
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | - Laurent Nahon
- Synchrotron SOLEIL
- L’Orme des Merisiers
- 91192 Gif sur Yvette
- France
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34
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WANG T, TANG XF, WEN ZY, ZHANG CH, ZHANG WJ. A Vacuum Ultraviolet Photoionization Time-of-Flight Mass Spectrometer for Investigation of Free Radical Reaction. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2020. [DOI: 10.1016/s1872-2040(19)61208-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Yang Z, Lin X, Zhou J, Hu M, Gai Y, Zhao W, Long B, Zhang W. Computational study on the mechanism and kinetics for the reaction between HO 2 and n-propyl peroxy radical. RSC Adv 2019; 9:40437-40444. [PMID: 35542643 PMCID: PMC9076281 DOI: 10.1039/c9ra07503h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 11/28/2019] [Indexed: 11/25/2022] Open
Abstract
The n-propyl peroxy radical (n-C3H7O2) is the key intermediate during atmospheric oxidation of propane (C3H8) which plays an important role in the carbon and nitrogen cycles in the troposphere. In this paper, a comprehensive theoretical study on the reaction mechanism and kinetics of the reaction between HO2 and n-C3H7O2 was performed at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-311G(d,p) level of theory. Computational results show that the HO2 + n-C3H7O2 reaction proceeds on both singlet and triplet potential energy surfaces (PESs). From an energetic point of view, the formation of C3H7O2H and 3O2via triplet hydrogen abstraction is the most favorable channel while other product channels are negligible. In addition, the calculated rate constants for the title reaction over the temperature range of 238–398 K were calculated by the multiconformer transition state theory (MC-TST), and the calculated rate constants show a negative temperature dependence. The contributions of the other four reaction channels to the total rate constant are negligible. The negative temperature dependence for the HO2 + n-C3H7O2 reaction in lower temperature regime.![]()
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Affiliation(s)
- Zhenli Yang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Hefei 230031 Anhui China .,University of Science and Technology of China Hefei 230026 China
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Hefei 230031 Anhui China
| | - Jiacheng Zhou
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Hefei 230031 Anhui China .,University of Science and Technology of China Hefei 230026 China
| | - Mingfeng Hu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Hefei 230031 Anhui China
| | - Yanbo Gai
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Hefei 230031 Anhui China
| | - Weixiong Zhao
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Hefei 230031 Anhui China
| | - Bo Long
- College of Computer and Information Engineering, Guizhou Minzu University Guiyang 550025 China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences Hefei 230031 Anhui China .,School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China Hefei 230026 Anhui China
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36
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Tavakol H, Ranjbari MA, Jafari-Chermahini MT. Mechanistic details for the reaction of methyl acrylate radical anion: a DFT study. REACTION KINETICS MECHANISMS AND CATALYSIS 2019. [DOI: 10.1007/s11144-019-01647-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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37
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Minamida M, Tanaka K, Tonokura K. Kinetic study of the oxidation reaction of 4‐methylphenyl radical. INT J CHEM KINET 2019. [DOI: 10.1002/kin.21331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Maya Minamida
- Department of Environment Systems, Graduate School of Frontier SciencesThe University of Tokyo Chiba Japan
| | - Kotaro Tanaka
- Department of Mechanical system Engineering, Faculty of EngineeringIbaraki University Hitachi‐shi Japan
| | - Kenichi Tonokura
- Department of Environment Systems, Graduate School of Frontier SciencesThe University of Tokyo Chiba Japan
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38
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Liu Q, Liu T, Chen Y, Xu J, Gao W, Zhang H, Yao Y. Effects of aerosols on the surface ozone generation via a study of the interaction of ozone and its precursors during the summer in Shanghai, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 675:235-246. [PMID: 31030131 DOI: 10.1016/j.scitotenv.2019.04.121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
Previous studies have shown that heavy aerosol pollution can inhibit the surface ozone generation. More recent studies, however, have revealed that aerosol loading is positively correlated with ozone concentrations in large cities, such as Shanghai, particularly during the summer. Whether the correlation between aerosol pollution and ozone concentrations is positive or negative, it is an issue that needs to be considered by atmospheric scientists. Although the presence of ozone precursors, such as nitrogen oxide (NOx) and volatile organic compounds (VOCs), affect ozone concentrations, the roles of aerosols in the formation of ozone have rarely been investigated. Therefore, an analysis of the effect of aerosols on photochemical ozone generation via a study of the interaction of ozone and its precursors is important. In our research, we found that both aerosol and ozone concentrations were higher in Shanghai under polluted conditions than they were under clean conditions during the summer, but the ozone formation was controlled by VOCs, not by aerosol loading. The decrease in the AOD (SSA) increased (decreased) the surface UV radiation and promoted (inhibited) photochemical ozone production. We also found that the lower the concentration of photochemically active VOCs, the weaker the effect of the AOD on the ozone concentrations. The other results were shown as follows: (1) Aerosol pollution decreased the amount of UV radiation reaching the Earth's surface, but the surface UV radiation increased with increasing aerosol particle scattering; (2) Aerosol pollution inhibited the photolysis of nitrogen dioxide (NO2), while the scattering property of aerosols facilitated this phenomenon; (3) When both the concentration of ozone precursors and the SSA were constant, the ozone concentration decreased, but the attenuation rate increased significantly with an increase in AOD.
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Affiliation(s)
- Qiong Liu
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; College of Information Science and Technology, Donghua University, Shanghai 201620, China
| | - Tongqiang Liu
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
| | - Yonghang Chen
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
| | - Jianming Xu
- Shanghai Key Laboratory of Meteorology and Health, Shanghai 200030, China; Shanghai Meteorological Service, Shanghai 200030, China
| | - Wei Gao
- Shanghai Key Laboratory of Meteorology and Health, Shanghai 200030, China; Shanghai Meteorological Service, Shanghai 200030, China
| | - Hua Zhang
- State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Yifeng Yao
- College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
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39
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Zhang F, Huang C. Pressure-Dependent Kinetics of the Reaction between CH 3OO and OH Focusing on the Product Yield of Methyltrioxide (CH 3OOOH). J Phys Chem Lett 2019; 10:3598-3603. [PMID: 31192603 DOI: 10.1021/acs.jpclett.9b00781] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The reaction kinetics of methyl peroxy radical (CH3OO) and hydroxyl radical (OH) has attracted an increasing level of interest in the past decade, while the branching yields of various product channels are still under debate. In this work, a comprehensive theoretical effort was made to investigate the branching yield of the stabilized methyltrioxide (CH3OOOH, TRIOX) adduct, which has recently been a research focus. Our computed branching ratio of TRIOX at 298 K and 760 Torr is ∼0.04, in agreement with the result of multiplexed photoionization mass spectrometry. We show that the large branching yield obtained in an early theoretical study mainly originated from the collision-induced strong stabilization presented in their simulation. Our findings clarify the controversial product yield results for this important species in recent studies. The computed rate constants over wide temperature and pressure ranges allow better integration of this reaction into global atmospheric models and low-temperature combustion kinetic models.
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Affiliation(s)
- Feng Zhang
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei , Anhui 230029 , P. R. China
| | - Can Huang
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei , Anhui 230029 , P. R. China
- Center for Combustion Energy and Key Laboratory for Thermal Science and Power Engineering of MOE , Tsinghua University , Beijing 100084 , P. R. China
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40
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Welch BK, Dawes R, Bross DH, Ruscic B. An Automated Thermochemistry Protocol Based on Explicitly Correlated Coupled-Cluster Theory: The Methyl and Ethyl Peroxy Families. J Phys Chem A 2019; 123:5673-5682. [DOI: 10.1021/acs.jpca.9b04381] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bradley K. Welch
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - Richard Dawes
- Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, United States
| | - David H. Bross
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
- Consortium for Advanced Science and Engineering, University of Chicago, Chicago, Illinois 60637, United States
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41
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42
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Hui AO, Fradet M, Okumura M, Sander SP. Temperature Dependence Study of the Kinetics and Product Yields of the HO 2 + CH 3C(O)O 2 Reaction by Direct Detection of OH and HO 2 Radicals Using 2f-IR Wavelength Modulation Spectroscopy. J Phys Chem A 2019; 123:3655-3671. [PMID: 30942073 DOI: 10.1021/acs.jpca.9b00442] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The HO2 + CH3C(O)O2 reaction consists of three product channels: CH3C(O)OOH + O2 (R1a), CH3C(O)OH + O3 (R1b), and OH + CH3C(O)O + O2 (R1c). The overall rate constant ( k1) and product yields (α1a, α1b, and α1c) were determined over the atmospherically relevant temperature range of 230-294 K at 100 Torr in N2. Time-resolved kinetics measurements were performed in a pulsed laser photolysis experiment in a slow flow cell by employing simultaneous infrared (IR) and ultraviolet (UV) absorption spectroscopy. HO2 and CH3C(O)O2 were formed by Cl-atom reactions with CH3OH and CH3CHO, respectively. Heterodyne near- and mid-infrared (NIR and MIR) wavelength modulation spectroscopy (WMS) was employed to selectively detect HO2 and OH radicals. Ultraviolet absorption at 225 and 250 nm was used to detect various peroxy radicals as well as ozone (O3). These experimental techniques enabled direct measurements of α1c and α1b via time-resolved spectroscopic detection in the MIR and the UV, respectively. At each temperature, experiments were performed at various ratios of initial HO2 and CH3C(O)O2 concentrations to quantify the secondary chemistry. The Arrhenius expression was found to be k1( T) = 1.38-0.63+1.17 × 10-12 exp[(730 ± 170)/ T] cm3 molecule-1 s-1. α1a was temperature-independent while α1b and α1c decreased and increased, respectively, with increasing temperatures. These trends are consistent with the current recommendation by the IUPAC data evaluation. Hydrogen-bonded adducts of HO2 with the precursors, HO2·CH3OH and HO2·CH3CHO, played a role at lower temperatures; as part of this work, rate enhancements of the HO2 self-reaction due to reactions of the adducts with HO2 were also measured.
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Affiliation(s)
- Aileen O Hui
- Arthur Amos Noyes Laboratory of Chemical Physics, Division of Chemistry and Chemical Physics , California Institute of Technology , M/S 127-72, 1200 East California Boulevard , Pasadena , California 91125 , United States
| | - Mathieu Fradet
- Jet Propulsion Laboratory , California Institute of Technology , 4800 Oak Grove Drive , Pasadena , California 91109 , United States
| | - Mitchio Okumura
- Arthur Amos Noyes Laboratory of Chemical Physics, Division of Chemistry and Chemical Physics , California Institute of Technology , M/S 127-72, 1200 East California Boulevard , Pasadena , California 91125 , United States
| | - Stanley P Sander
- Jet Propulsion Laboratory , California Institute of Technology , 4800 Oak Grove Drive , Pasadena , California 91109 , United States
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43
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Arsene I, Gorinchioy N. DFT Study of the Entire Reaction Cycle of H2O2 Decomposition and O2 Generation Catalyzed by Fenton Reagent. CHEMISTRY JOURNAL OF MOLDOVA 2019. [DOI: 10.19261/cjm.2018.543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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44
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Bianchi F, Kurtén T, Riva M, Mohr C, Rissanen MP, Roldin P, Berndt T, Crounse JD, Wennberg PO, Mentel TF, Wildt J, Junninen H, Jokinen T, Kulmala M, Worsnop DR, Thornton JA, Donahue N, Kjaergaard HG, Ehn M. Highly Oxygenated Organic Molecules (HOM) from Gas-Phase Autoxidation Involving Peroxy Radicals: A Key Contributor to Atmospheric Aerosol. Chem Rev 2019; 119:3472-3509. [PMID: 30799608 PMCID: PMC6439441 DOI: 10.1021/acs.chemrev.8b00395] [Citation(s) in RCA: 205] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
![]()
Highly
oxygenated organic molecules (HOM) are formed in the atmosphere
via autoxidation involving peroxy radicals arising from volatile organic
compounds (VOC). HOM condense on pre-existing particles and can be
involved in new particle formation. HOM thus contribute to the formation
of secondary organic aerosol (SOA), a significant and ubiquitous component
of atmospheric aerosol known to affect the Earth’s radiation
balance. HOM were discovered only very recently, but the interest
in these compounds has grown rapidly. In this Review, we define HOM
and describe the currently available techniques for their identification/quantification,
followed by a summary of the current knowledge on their formation
mechanisms and physicochemical properties. A main aim is to provide
a common frame for the currently quite fragmented literature on HOM
studies. Finally, we highlight the existing gaps in our understanding
and suggest directions for future HOM research.
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Affiliation(s)
- Federico Bianchi
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland.,Aerosol and Haze Laboratory , University of Chemical Technology , Beijing 100029 , P.R. China
| | - Theo Kurtén
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland
| | - Matthieu Riva
- IRCELYON, CNRS University of Lyon , Villeurbanne 69626 , France
| | - Claudia Mohr
- Department of Environmental Science and Analytical Chemistry , Stockholm University , Stockholm 11418 , Sweden
| | - Matti P Rissanen
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland
| | - Pontus Roldin
- Division of Nuclear Physics, Department of Physics , Lund University , Lund 22100 , Sweden
| | - Torsten Berndt
- Leibniz Institute for Tropospheric Research , Leipzig 04318 , Germany
| | - John D Crounse
- Division of Geological and Planetary Sciences , California Institute of Technology , Pasadena , California 91125 , United States
| | - Paul O Wennberg
- Division of Geological and Planetary Sciences , California Institute of Technology , Pasadena , California 91125 , United States
| | - Thomas F Mentel
- Institut für Energie und Klimaforschung, IEK-8 , Forschungszentrum Jülich GmbH , Jülich 52425 , Germany
| | - Jürgen Wildt
- Institut für Energie und Klimaforschung, IEK-8 , Forschungszentrum Jülich GmbH , Jülich 52425 , Germany
| | - Heikki Junninen
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland.,Institute of Physics , University of Tartu , Tartu 50090 , Estonia
| | - Tuija Jokinen
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland
| | - Markku Kulmala
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland.,Aerosol and Haze Laboratory , University of Chemical Technology , Beijing 100029 , P.R. China
| | - Douglas R Worsnop
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland.,Aerodyne Research Inc. , Billerica , Massachusetts 01821 , United States
| | - Joel A Thornton
- Department of Atmospheric Sciences , University of Washington , Seattle , Washington 98195 , United States
| | - Neil Donahue
- Center for Atmospheric Particle Studies , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Henrik G Kjaergaard
- Department of Chemistry , University of Cøpenhagen , Cøpenhagen 2100 , Denmark
| | - Mikael Ehn
- Institute for Atmospheric and Earth System Research, Faculty of Science , University of Helsinki , Helsinki 00014 , Finland
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45
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Franke PR, Moore KB, Schaefer HF, Douberly GE. tert-Butyl peroxy radical: ground and first excited state energetics and fundamental frequencies. Phys Chem Chem Phys 2019; 21:9747-9758. [DOI: 10.1039/c9cp01476d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The lowest adiabatic electronic transition origin and fundamental vibrational frequencies are computed, with high accuracy, for the tert-butyl peroxy radical.
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Affiliation(s)
| | - Kevin B. Moore
- Department of Chemistry
- University of Georgia
- Athens
- USA
- Center for Computational Quantum Chemistry
| | - Henry F. Schaefer
- Department of Chemistry
- University of Georgia
- Athens
- USA
- Center for Computational Quantum Chemistry
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46
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Wen Z, Tang X, Wang C, Fittschen C, Wang T, Zhang C, Yang J, Pan Y, Liu F, Zhang W. A vacuum ultraviolet photoionization time-of-flight mass spectrometer with high sensitivity for study of gas-phase radical reaction in a flow tube. INT J CHEM KINET 2018. [DOI: 10.1002/kin.21241] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zuoying Wen
- Laboratory of Atmospheric Physico-Chemistry; Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei China
- Graduate School; University of Science and Technology of China; Hefei China
| | - Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry; Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei China
| | - Chengcheng Wang
- Laboratory of Atmospheric Physico-Chemistry; Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei China
- Graduate School; University of Science and Technology of China; Hefei China
| | - Christa Fittschen
- University Lille; PC2A, UMR CNRS-ULille 8522 Villeneuve d'Ascq France
| | - Tao Wang
- Laboratory of Atmospheric Physico-Chemistry; Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei China
| | - Cuihong Zhang
- Laboratory of Atmospheric Physico-Chemistry; Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei China
- Graduate School; University of Science and Technology of China; Hefei China
| | - Jiuzhong Yang
- National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei China
| | - Yang Pan
- National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei China
| | - Fuyi Liu
- National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry; Anhui Institute of Optics and Fine Mechanics; Chinese Academy of Sciences; Hefei China
- School of Environmental Science and Optoelectronic Technology; University of Science and Technology of China; Hefei China
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47
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Rissanen MP. NO 2 Suppression of Autoxidation-Inhibition of Gas-Phase Highly Oxidized Dimer Product Formation. ACS EARTH & SPACE CHEMISTRY 2018; 2:1211-1219. [PMID: 30488044 PMCID: PMC6251564 DOI: 10.1021/acsearthspacechem.8b00123] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/10/2018] [Accepted: 10/12/2018] [Indexed: 06/09/2023]
Abstract
Atmospheric autoxidation of volatile organic compounds (VOC) leads to prompt formation of highly oxidized multifunctional compounds (HOM) that have been found crucial in forming ambient secondary organic aerosol (SOA). As a radical chain reaction mediated by oxidized peroxy (RO2) and alkoxy (RO) radical intermediates, the formation pathways can be intercepted by suitable reaction partners, preventing the production of the highest oxidized reaction products, and thus the formation of the most condensable material. Commonly, NO is expected to have a detrimental effect on RO2 chemistry, and thus on autoxidation, whereas the influence of NO2 is mostly neglected. Here it is shown by dedicated flow tube experiments, how high concentration of NO2 suppresses cyclohexene ozonolysis initiated autoxidation chain reaction. Importantly, the addition of NO2 ceases covalently bound dimer production, indicating their production involving acylperoxy radical (RC(O)OO•) intermediates. In related experiments NO was also shown to strongly suppress the highly oxidized product formation, but due to possibility for chain propagating reactions (as with RO2 and HO2 too), the suppression is not as absolute as with NO2. Furthermore, it is shown how NO x reactions with oxidized peroxy radicals lead into indistinguishable product compositions, complicating mass spectral assignments in any RO2 + NO x system. The present work was conducted with atmospheric pressure chemical ionization mass spectrometry (CIMS) as the detection method for the highly oxidized end-products and peroxy radical intermediates, under ambient conditions and at short few second reaction times. Specifically, the insight was gained by addition of a large amount of NO2 (and NO) to the oxidation system, upon which acylperoxy radicals reacted in RC(O)O2 + NO2 → RC(O)O2NO2 reaction to form peroxyacylnitrates, consequently shutting down the oxidation sequence.
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Affiliation(s)
- Matti P. Rissanen
- Institute for Atmospheric
and Earth System Research (INAR), University
of Helsinki, Helsinki, Finland
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48
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Asili V, De Visscher A. Modelling methane and ethane photolysis in waste gas: Optimization of reaction networks. CAN J CHEM ENG 2018. [DOI: 10.1002/cjce.23124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Vahid Asili
- Department of Chemical and Petroleum Engineering; Centre for Environmental Engineering Research and Education (CEERE); University of Calgary; 2500 University Drive NW; Calgary AB T2N 1N4 Canada
| | - Alex De Visscher
- Department of Chemical and Petroleum Engineering; Centre for Environmental Engineering Research and Education (CEERE); University of Calgary; 2500 University Drive NW; Calgary AB T2N 1N4 Canada
- Current address: Department of Chemical and Materials Engineering; Faculty of Engineering and Computer Science; Concordia University; 1455 de Maisonneuve Blvd. E Montréal QC, H3G 2W1 Canada
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49
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Chattopadhyay A, Samanta M, Mondal K, Chakraborty T. Mid-infrared quantum cascade laser spectroscopy probing of the kinetics of an atmospherically significant radical reaction,
$$\hbox {CH}_{3}\hbox {O}_{2}+\hbox {NO}_{2}+\hbox {M}\rightarrow \hbox {CH}_{3}\hbox {O}_{2}\hbox {NO}_{2}+\hbox {M}$$
CH
3
O
2
+
NO
2
+
M
→
CH
3
O
2
NO
2
+
M
, in the gas phase. J CHEM SCI 2018. [DOI: 10.1007/s12039-018-1451-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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50
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Murschell T, Farmer DK. Atmospheric OH Oxidation of Three Chlorinated Aromatic Herbicides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:4583-4591. [PMID: 29601726 DOI: 10.1021/acs.est.7b06025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Chlorinated phenoxy acids are a widely used class of herbicides and have been found in remote regions far from sources. However, the atmospheric chemistry of these compounds is poorly understood. We use an oxidative flow reactor coupled to chemical ionization mass spectrometry to investigate OH oxidation of two chlorinated phenoxyacid herbicides (2-methyl-4-chlorophenoxyacetic acid (MCPA) and mecoprop-p) and one chlorinated pyridine herbicide (triclopyr). OH radicals add to the aromatic rings of the three herbicides, produce peroxides via hydrogen abstraction, or fragment at the ether bond. OH oxidation of MCPA produced two potentially toxic compounds: chlorosalicylaldehyde and chlorosalicylic acid. We use standards to validate the detection of these oxidation products by acetate CIMS and quantify the reaction rate. Oxidation of triclopyr produced a known endocrine disruptor, 3,5,6-trichloro-2-pyridinol. Thus, while some OH oxidation products are less toxic than the parent molecules (e.g., C1-5 carboxylic acids), others may be as or more toxic than the parent herbicide. We determine effective rate coefficients for OH addition to the aromatic ring ( kOH) for mecoprop-p of 1.5 (±0.7) × 10-12 cm3 molecules-1 s-1 and for MCPA of 2.6 (±0.3) × 10-12 cm3 molecules-1 s-1. The atmospheric lifetimes with respect to OH are thus long enough that photochemistry may be relevant to the environmental fate of these pesticides.
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Affiliation(s)
- Trey Murschell
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
| | - Delphine K Farmer
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
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