Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion
<p>Gas-phase oxidation pathways and products of anthropogenic volatile organic compounds (VOCs), mainly aromatics, are the subject of intensive research, with attention paid to their contributions to secondary organic aerosol (SOA) formation and potentially new particle formation (NPF) in the...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/20/9563/2020/acp-20-9563-2020.pdf |
| _version_ | 1818454540551192576 |
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| author | Y. Wang A. Mehra J. E. Krechmer G. Yang X. Hu Y. Lu A. Lambe M. Canagaratna J. Chen D. Worsnop H. Coe L. Wang L. Wang L. Wang |
| author_facet | Y. Wang A. Mehra J. E. Krechmer G. Yang X. Hu Y. Lu A. Lambe M. Canagaratna J. Chen D. Worsnop H. Coe L. Wang L. Wang L. Wang |
| author_sort | Y. Wang |
| collection | DOAJ |
| description | <p>Gas-phase oxidation pathways and products of anthropogenic
volatile organic compounds (VOCs), mainly aromatics, are the subject of
intensive research, with attention paid to their contributions to secondary
organic aerosol (SOA) formation and potentially new particle formation
(NPF) in the urban atmosphere. In this study, a series of OH-initiated
oxidation experiments of trimethylbenzene (TMB, <span class="inline-formula">C<sub>9</sub>H<sub>12</sub></span>) including
1,2,4-TMB, 1,3,5-TMB, 1,2,3-TMB, and 1,2,4-(methyl-D3)-TMBs
(<span class="inline-formula">C<sub>9</sub>H<sub>9</sub>D<sub>3</sub></span>) were investigated in an oxidation flow reactor
(OFR) in the absence and presence of <span class="inline-formula">NO<sub><i>x</i></sub></span>. Products were measured using
a suite of state-of-the-art instruments, i.e. a nitrate-based chemical
ionization–atmospheric pressure interface time-of-flight mass spectrometer
(nitrate CI-APi-TOF), an iodide-adduct chemical ionization time-of-flight
mass spectrometer (iodide CI-TOF) equipped with a Filter Inlet for Gases and
AEROsols (FIGAERO), and a Vocus proton-transfer-reaction mass spectrometer
(Vocus PTR). A large number of <span class="inline-formula">C<sub>9</sub></span> products with 1–11 oxygen atoms and <span class="inline-formula">C<sub>18</sub></span>
products presumably formed from dimerization of <span class="inline-formula">C<sub>9</sub></span> peroxy radicals were
observed, hinting at the extensive existence of autoxidation and accretion
reaction pathways in the OH-initiated oxidation reactions of TMBs. Oxidation
products of 1,2,4-(methyl-D3)-TMBs with deuterium atoms in different methyl
substituents were then used as a molecular basis to propose potential
autoxidation reaction pathways. Accretion of <span class="inline-formula">C<sub>9</sub></span> peroxy radicals is the most
significant for aromatics with meta-substituents and the least for aromatics
with ortho-substituents if the number and size of substituted groups are
identical. The presence of <span class="inline-formula">NO<sub><i>x</i></sub></span> would suppress the formation of highly oxygenated molecules (HOMs) of <span class="inline-formula">C<sub>18</sub></span> and enhance the formation of
organonitrates and even dinitrate organic compounds. Our results show that
the oxidation products of TMB are much more diverse and could be more
oxygenated than the current mechanisms predict.</p> |
| first_indexed | 2024-12-14T21:56:30Z |
| format | Article |
| id | doaj.art-15a72a929cc1463bb33d64e7945d0182 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-14T21:56:30Z |
| publishDate | 2020-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-15a72a929cc1463bb33d64e7945d01822022-12-21T22:46:07ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242020-08-01209563957910.5194/acp-20-9563-2020Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretionY. Wang0A. Mehra1J. E. Krechmer2G. Yang3X. Hu4Y. Lu5A. Lambe6M. Canagaratna7J. Chen8D. Worsnop9H. Coe10L. Wang11L. Wang12L. Wang13Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Jiangwan Campus, Fudan University, Shanghai 200438, ChinaCentre for Atmospheric Science, School of Earth and Environment Sciences, The University of Manchester, Manchester, M13 9PL, UKCenter for Aerosol and Cloud Chemistry, Aerodyne Research Inc., Billerica, MA, USAShanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Jiangwan Campus, Fudan University, Shanghai 200438, ChinaShanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Jiangwan Campus, Fudan University, Shanghai 200438, ChinaShanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Jiangwan Campus, Fudan University, Shanghai 200438, ChinaCenter for Aerosol and Cloud Chemistry, Aerodyne Research Inc., Billerica, MA, USACenter for Aerosol and Cloud Chemistry, Aerodyne Research Inc., Billerica, MA, USAShanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Jiangwan Campus, Fudan University, Shanghai 200438, ChinaCenter for Aerosol and Cloud Chemistry, Aerodyne Research Inc., Billerica, MA, USACentre for Atmospheric Science, School of Earth and Environment Sciences, The University of Manchester, Manchester, M13 9PL, UKShanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Department of Environmental Science and Engineering, Jiangwan Campus, Fudan University, Shanghai 200438, ChinaCollaborative Innovation Center of Climate Change, Nanjing 210023, ChinaShanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China<p>Gas-phase oxidation pathways and products of anthropogenic volatile organic compounds (VOCs), mainly aromatics, are the subject of intensive research, with attention paid to their contributions to secondary organic aerosol (SOA) formation and potentially new particle formation (NPF) in the urban atmosphere. In this study, a series of OH-initiated oxidation experiments of trimethylbenzene (TMB, <span class="inline-formula">C<sub>9</sub>H<sub>12</sub></span>) including 1,2,4-TMB, 1,3,5-TMB, 1,2,3-TMB, and 1,2,4-(methyl-D3)-TMBs (<span class="inline-formula">C<sub>9</sub>H<sub>9</sub>D<sub>3</sub></span>) were investigated in an oxidation flow reactor (OFR) in the absence and presence of <span class="inline-formula">NO<sub><i>x</i></sub></span>. Products were measured using a suite of state-of-the-art instruments, i.e. a nitrate-based chemical ionization–atmospheric pressure interface time-of-flight mass spectrometer (nitrate CI-APi-TOF), an iodide-adduct chemical ionization time-of-flight mass spectrometer (iodide CI-TOF) equipped with a Filter Inlet for Gases and AEROsols (FIGAERO), and a Vocus proton-transfer-reaction mass spectrometer (Vocus PTR). A large number of <span class="inline-formula">C<sub>9</sub></span> products with 1–11 oxygen atoms and <span class="inline-formula">C<sub>18</sub></span> products presumably formed from dimerization of <span class="inline-formula">C<sub>9</sub></span> peroxy radicals were observed, hinting at the extensive existence of autoxidation and accretion reaction pathways in the OH-initiated oxidation reactions of TMBs. Oxidation products of 1,2,4-(methyl-D3)-TMBs with deuterium atoms in different methyl substituents were then used as a molecular basis to propose potential autoxidation reaction pathways. Accretion of <span class="inline-formula">C<sub>9</sub></span> peroxy radicals is the most significant for aromatics with meta-substituents and the least for aromatics with ortho-substituents if the number and size of substituted groups are identical. The presence of <span class="inline-formula">NO<sub><i>x</i></sub></span> would suppress the formation of highly oxygenated molecules (HOMs) of <span class="inline-formula">C<sub>18</sub></span> and enhance the formation of organonitrates and even dinitrate organic compounds. Our results show that the oxidation products of TMB are much more diverse and could be more oxygenated than the current mechanisms predict.</p>https://acp.copernicus.org/articles/20/9563/2020/acp-20-9563-2020.pdf |
| spellingShingle | Y. Wang A. Mehra J. E. Krechmer G. Yang X. Hu Y. Lu A. Lambe M. Canagaratna J. Chen D. Worsnop H. Coe L. Wang L. Wang L. Wang Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion Atmospheric Chemistry and Physics |
| title | Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion |
| title_full | Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion |
| title_fullStr | Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion |
| title_full_unstemmed | Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion |
| title_short | Oxygenated products formed from OH-initiated reactions of trimethylbenzene: autoxidation and accretion |
| title_sort | oxygenated products formed from oh initiated reactions of trimethylbenzene autoxidation and accretion |
| url | https://acp.copernicus.org/articles/20/9563/2020/acp-20-9563-2020.pdf |
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