1
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Nozière B, Vereecken L. H-shift and cyclization reactions in unsaturated alkylperoxy radicals near room temperature: propagating or terminating autoxidation? Phys Chem Chem Phys 2024; 26:25373-25384. [PMID: 39311679 PMCID: PMC11418804 DOI: 10.1039/d4cp02718c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2024] [Accepted: 09/12/2024] [Indexed: 09/25/2024]
Abstract
The autoxidation of alkylperoxy radicals (RO2, where R is organic) is an important degradation pathway for organic compounds in a wide range of chemical systems including Earth's atmosphere. It is thought to proceed by internal H-shift reactions and, for unsaturated radicals, cyclization. However, experimental data on specific reactions steps for unsaturated RO2 is scarce. This work investigates the unimolecular reactions of 1-butenyl-O2, 1-pentenyl-O2, 1-hexenyl-O2, and 2-methyl-2-pentenyl-O2 radicals near room temperature (302 ± 3 K) experimentally, by monitoring the radicals directly, and theoretically. The experimental rate coefficients are in good agreement with those determined with high-level quantum calculations, confirming that cyclization can be competitive with H-shift in some cases. However, the products observed experimentally with two different mass spectrometers suggest that all the peroxy radicals studied lead to fast decomposition (k > 1 s-1) after the isomerization step. While the mechanisms for these decompositions could not be fully elucidated theoretically, they question whether these channels contribute to propagation or to termination of the autoxidation chains.
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Affiliation(s)
- Barbara Nozière
- Department of Chemistry, Royal Institute of Technology, KTH, 11428, Stockholm, Sweden.
| | - Luc Vereecken
- Institute of Climate and Energy Systems, ICE-3: Troposphere Forschungszentrum Jülich GmbH Jülich, Germany.
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2
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Fu Z, Guo S, Yu Y, Xie HB, Li S, Lv D, Zhou P, Song K, Chen Z, Tan R, Hu K, Shen R, Yao M, Hu M. Oxidation Mechanism and Toxicity Evolution of Linalool, a Typical Indoor Volatile Chemical Product. ENVIRONMENT & HEALTH (WASHINGTON, D.C.) 2024; 2:486-498. [PMID: 39049896 PMCID: PMC11264274 DOI: 10.1021/envhealth.4c00033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 07/27/2024]
Abstract
Linalool, a high-reactivity volatile chemical product (VCP) commonly found in cleaning products and disinfectants, is increasingly recognized as an emerging contaminant, especially in indoor air. Understanding the gas-phase oxidation mechanism of linalool is crucial for assessing its impact on atmospheric chemistry and human health. Using quantum chemical calculations and computational toxicology simulations, we investigated the atmospheric transformation and toxicity evolution of linalool under low and high NO/HO2· levels, representing indoor and outdoor environments. Our findings reveal that linalool can undergo the novel mechanisms involving concerted peroxy (RO2·) and alkoxy radical (RO·) modulated autoxidation, particularly emphasizing the importance of cyclization reactions indoors. This expands the widely known RO2·-dominated H-shift-driven autoxidation and proposes a generalized autoxidation mechanism that leads to the formation of low-volatility secondary organic aerosol (SOA) precursors. Toxicological analysis shows that over half of transformation products (TPs) exhibited higher carcinogenicity and respiratory toxicity compared to linalool. We also propose time-dependent toxic effects of TPs to assess their long-term toxicity. Our results indicate that the strong indoor emission coupled with slow consumption rates lead to significant health risks under an indoor environment. The results highlight complex indoor air chemistry and health concerns regarding persistent toxic products during indoor cleaning, which involves the use of linalool or other VCPs.
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Affiliation(s)
- Zihao Fu
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Song Guo
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Collaborative
Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China
| | - Ying Yu
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Hong-Bin Xie
- Key
Laboratory of Industrial Ecology and Environmental Engineering (Ministry
of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Shiyu Li
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Daqi Lv
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Putian Zhou
- Institute
for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki, Finland
| | - Kai Song
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Zheng Chen
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Rui Tan
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Kun Hu
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Ruizhe Shen
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Maosheng Yao
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Min Hu
- State
Key Joint Laboratory of Environmental Simulation and Pollution Control,
International Joint Laboratory for Regional Pollution Control, Ministry
of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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3
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Nozière B, Durif O, Dubus E, Kylington S, Emmer Å, Fache F, Piel F, Wisthaler A. The reaction of organic peroxy radicals with unsaturated compounds controlled by a non-epoxide pathway under atmospheric conditions. Phys Chem Chem Phys 2023; 25:7772-7782. [PMID: 36857663 PMCID: PMC10015623 DOI: 10.1039/d2cp05166d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Today, the reactions of gas-phase organic peroxy radicals (RO2) with unsaturated Volatile Organic Compounds (VOC) are expected to be negligible at room temperature and ignored in atmospheric chemistry. This assumption is based on combustion studies (T ≥ 360 K), which were the only experimental data available for these reactions until recently. These studies also reported epoxide formation as the only reaction channel. In this work, the products of the reactions of 1-pentylperoxy (C5H11O2) and methylperoxy (CH3O2) with 2,3-dimethyl-2-butene ("2,3DM2B") and isoprene were investigated at T = 300 ± 5 K with Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) and Gas Chromatography/Electron Impact Mass Spectrometry. Unlike what was expected, the experiments showed no measurable formation of epoxide. However, RO2 + alkene was found to produce compounds retaining the alkene structure, such as 3-hydroxy-3-methyl-2-butanone (C5H10O2) with 2,3DM2B and 2-hydroxy-2-methyl-3-butenal (C5H8O2) and methyl vinyl ketone with isoprene, suggesting that these reactions proceed through another reaction pathway under atmospheric conditions. We propose that, instead of forming an epoxide, the alkyl radical produced by the addtion of RO2 onto the alkene reacts with oxygen, producing a peroxy radical. The corresponding mechanisms are consistent with the products observed in the experiments. This alternative pathway implies that, under atmospheric conditions, RO2 + alkene reactions are kinetically limited by the initial addition step and not by the epoxide formation proposed until now for combustion systems. Extrapolating the combustion data to room temperature thus underestimates the rate coefficients, which is consistent with those recently reported for these reactions at room temperature. While slow for many classes of RO2, these reactions could be non-negligible at room temperature for some functionalized RO2. They might thus need to be considered in laboratory studies using large alkene concentrations and in biogenically-dominated regions of the atmosphere.
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Affiliation(s)
- Barbara Nozière
- KTH, Royal Institute of Technology, Department of Chemistry, 114 28 Stockholm, Sweden.
| | - Olivier Durif
- KTH, Royal Institute of Technology, Department of Chemistry, 114 28 Stockholm, Sweden.
| | - Eloé Dubus
- KTH, Royal Institute of Technology, Department of Chemistry, 114 28 Stockholm, Sweden.
| | - Stephanie Kylington
- KTH, Royal Institute of Technology, Department of Chemistry, 114 28 Stockholm, Sweden.
| | - Åsa Emmer
- KTH, Royal Institute of Technology, Department of Chemistry, 114 28 Stockholm, Sweden.
| | - Fabienne Fache
- Université Lyon 1 and CNRS, UMR 5246, ICBMS, 69626 Villeurbanne, France
| | - Felix Piel
- University of Oslo, Department of Chemistry, 0315 Oslo, Norway
| | - Armin Wisthaler
- University of Oslo, Department of Chemistry, 0315 Oslo, Norway
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4
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Mayorga R, Xia Y, Zhao Z, Long B, Zhang H. Peroxy Radical Autoxidation and Sequential Oxidation in Organic Nitrate Formation during Limonene Nighttime Oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:15337-15346. [PMID: 36282674 DOI: 10.1021/acs.est.2c04030] [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: 06/16/2023]
Abstract
Limonene is an abundant monoterpene released into the atmosphere via biogenic emissions and biomass burning. However, the atmospheric oxidation and secondary organic aerosol (SOA) formation mechanisms of limonene, especially during nighttime, remain largely understudied. In this work, limonene was oxidized synergistically by ozone (O3) and nitrate radicals (NO3) in a flow tube reactor and a continuous flow stirred tank reactor. Upon oxidation, many highly oxidized organic nitrates and nitrooxy peroxy radicals (RO2) were observed in the gas phase within 1 min. Combining quantum chemical calculations with kinetic simulations, we found that the primary nitrooxy RO2 (C10H16NO5) through NO3 addition at the more substituted endocyclic double bond and at the exocyclic double bond (previously considered as minor pathways) can undergo autoxidation with rate constants of around 0.02 and 20 s-1 at 298 K, respectively. These pathways could explain a major portion of the observed highly oxidized organic nitrates. In the SOA, highly oxidized mono- and dinitrates (e.g., C10H17NO7-8 and C10H16,18N2O8-10) make up a significant contribution, highlighting nitrooxy RO2 autoxidation and sequential NO3 oxidation of limonene. The same organic nitrates are also observed in ambient aerosol during biomass burning and nighttime in the southeastern United States. Therefore, the present work provides new insights into the nighttime oxidation of limonene and SOA formation in the atmosphere.
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Affiliation(s)
- Raphael Mayorga
- Department of Chemistry, University of California, Riverside, California 92507, United States
| | - Yu Xia
- School of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, China
| | - Zixu Zhao
- Department of Chemistry, University of California, Riverside, California 92507, United States
| | - Bo Long
- School of Materials Science and Engineering, Guizhou Minzu University, Guiyang 550025, China
| | - Haofei Zhang
- Department of Chemistry, University of California, Riverside, California 92507, United States
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5
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Shen H, Vereecken L, Kang S, Pullinen I, Fuchs H, Zhao D, Mentel TF. Unexpected significance of a minor reaction pathway in daytime formation of biogenic highly oxygenated organic compounds. SCIENCE ADVANCES 2022; 8:eabp8702. [PMID: 36269820 PMCID: PMC9586481 DOI: 10.1126/sciadv.abp8702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 09/01/2022] [Indexed: 06/16/2023]
Abstract
Secondary organic aerosol (SOA), formed by oxidation of volatile organic compounds, substantially influence air quality and climate. Highly oxygenated organic molecules (HOMs), particularly those formed from biogenic monoterpenes, contribute a large fraction of SOA. During daytime, hydroxyl radicals initiate monoterpene oxidation, mainly by hydroxyl addition to monoterpene double bonds. Naturally, related HOM formation mechanisms should be induced by that reaction route, too. However, for α-pinene, the most abundant atmospheric monoterpene, we find a previously unidentified competitive pathway under atmospherically relevant conditions: HOM formation is predominately induced via hydrogen abstraction by hydroxyl radicals, a generally minor reaction pathway. We show by observations and theoretical calculations that hydrogen abstraction followed by formation and rearrangement of alkoxy radicals is a prerequisite for fast daytime HOM formation. Our analysis provides an accurate mechanism and yield, demonstrating that minor reaction pathways can become major, here for SOA formation and growth and related impacts on air quality and climate.
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Affiliation(s)
- Hongru Shen
- Department of Atmospheric and Oceanic Sciences & Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
| | - Luc Vereecken
- Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Sungah Kang
- Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Iida Pullinen
- Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Hendrik Fuchs
- Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Physikalisches Institut, Universität zu Köln, 50932 Köln, Germany
| | - Defeng Zhao
- Department of Atmospheric and Oceanic Sciences & Institute of Atmospheric Sciences, Fudan University, Shanghai 200438, China
- Shanghai Frontiers Science Center of Atmosphere-Ocean Interaction, Fudan University, Shanghai 200438, China
- Institute of Eco-Chongming (IEC), 20 Cuiniao Rd., Chongming, Shanghai 202162, China
- IRDR ICoE on Risk Interconnectivity and Governance on Weather/Climate Extremes Impact and Public Health, Fudan University, Shanghai 200438, China
| | - Thomas F. Mentel
- Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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6
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Vereecken L, Novelli A, Kiendler-Scharr A, Wahner A. Unimolecular and water reactions of oxygenated and unsaturated Criegee intermediates under atmospheric conditions. Phys Chem Chem Phys 2022; 24:6428-6443. [DOI: 10.1039/d1cp05877k] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ozonolysis of unsaturated hydrocarbons (VOCs) is one of the main oxidation processes in the atmosphere. The stabilized Criegee intermediates (SCI) formed are highly reactive oxygenated species that potentially influence the...
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7
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Barber VP, Kroll JH. Chemistry of Functionalized Reactive Organic Intermediates in the Earth's Atmosphere: Impact, Challenges, and Progress. J Phys Chem A 2021; 125:10264-10279. [PMID: 34846877 DOI: 10.1021/acs.jpca.1c08221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The gas-phase oxidation of organic compounds is an important chemical process in the Earth's atmosphere. It governs oxidant levels and controls the production of key secondary pollutants, and hence has major implications for air quality and climate. Organic oxidation is largely controlled by the chemistry of a few reactive intermediates, namely, alkyl (R) radicals, alkoxy (RO) radicals, peroxy (RO2) radicals, and carbonyl oxides (R1R2COO), which may undergo a number of unimolecular and bimolecular reactions. Our understanding of these intermediates, and the reaction pathways available to them, is based largely on studies of unfunctionalized intermediates, formed in the first steps of hydrocarbon oxidation. However, it has become increasingly clear that intermediates with functional groups, which are generally formed later in the oxidation process, can exhibit fundamentally different reactivity than unfunctionalized ones. In this Perspective, we explore the unique chemistry available to functionalized organic intermediates in the Earth's atmosphere. After a brief review of the canonical chemistry available to unfunctionalized intermediates, we discuss how the addition of functional groups can introduce new reactions, either by changing the energetics or kinetics of a given reaction or by opening up new chemical pathways. We then provide examples of atmospheric reaction classes that are available only to functionalized intermediates. Some of these, such as unimolecular H-shift reactions of RO2 radicals, have been elucidated only relatively recently, and can have important impacts on atmospheric chemistry (e.g., on radical cycling or organic aerosol formation); it seems likely that other, as-yet undiscovered reactions of (multi)functional intermediates may also exist. We discuss the challenges associated with the study of the chemistry of such intermediates and review novel experimental and theoretical approaches that have recently provided (or hold promise for providing) new insights into their atmospheric chemistry. The continued use and development of such techniques and the close collaboration between experimentalists and theoreticians are necessary for a complete, detailed understanding of the chemistry of functionalized intermediates and their impact on major atmospheric chemical processes.
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Affiliation(s)
- Victoria P Barber
- Departments of Civil and Environmental Engineering and Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jesse H Kroll
- Departments of Civil and Environmental Engineering and Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Goldman MJ, Green WH, Kroll JH. Chemistry of Simple Organic Peroxy Radicals under Atmospheric through Combustion Conditions: Role of Temperature, Pressure, and NO x Level. J Phys Chem A 2021; 125:10303-10314. [PMID: 34843244 DOI: 10.1021/acs.jpca.1c07203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Organic peroxy radicals (RO2) are key intermediates in the oxidation of organic compounds in both combustion systems and the atmosphere. While many studies have focused on reactions of RO2 in specific applications, spanning a relatively limited range of reaction conditions, the generalized behavior of RO2 radicals across the full range of reaction conditions (temperatures, pressures, and NO levels) has, to our knowledge, never been explored. In this work, two simple model systems, n-propyl peroxy radical and γ-isobutanol peroxy radical, are used to evaluate RO2 fate using pressure-dependent kinetics. The fate of these radicals was modeled based on literature data over 250-1250 K, 0.01-100 bar, and 1 ppt to 100 ppm of NO, which spans the typical range of atmospheric and combustion conditions. Covering this entire range provides a broad overview of the reactivity of these species under both atmospheric and combustion conditions, as well as under conditions intermediate to the two. A particular focus is on the importance of reactions that were traditionally considered to occur in only one of the two sets of conditions: RO2 unimolecular isomerization reactions (long known to occur in combustion systems but only recently appreciated in atmospheric systems) and RO2 bimolecular reactions of RO2 with NO (thought to occur mainly in atmospheric systems and rarely considered in combustion chemistry).
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Affiliation(s)
- Mark Jacob Goldman
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - William H Green
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jesse H Kroll
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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