气候变化领域集成服务门户(CCPortal): Atmospheric photo-oxidation of myrcene: OH reaction rate constant, gas-phase oxidation products and radical budgets

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DOI	10.5194/acp-21-16067-2021
	Atmospheric photo-oxidation of myrcene: OH reaction rate constant, gas-phase oxidation products and radical budgets
	Tan Z.; Hantschke L.; Kaminski M.; Acir I.-H.; Bohn B.; Cho C.; Dorn H.-P.; Li X.; Novelli A.; Nehr S.; Rohrer F.; Tillmann R.; Wegener R.; Hofzumahaus A.; Kiendler-Scharr A.; Wahner A.; Fuchs H.
发表日期	2021
ISSN	1680-7316
起始页码	16067
结束页码	16091
卷号	21 期号:20
英文摘要	The photo-oxidation of myrcene, a monoterpene species emitted by plants, was investigated at atmospheric conditions in the outdoor simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a Large Reaction Chamber). The chemical structure of myrcene consists of one moiety that is a conjugated Ï€ system (similar to isoprene) and another moiety that is a triple-substituted olefinic unit (similar to 2-methyl-2-butene). Hydrogen shift reactions of organic peroxy radicals (RO2) formed in the reaction of isoprene with atmospheric OH radicals are known to be of importance for the regeneration of OH. Structure-activity relationships (SARs) suggest that similar hydrogen shift reactions like in isoprene may apply to the isoprenyl part of RO2 radicals formed during the OH oxidation of myrcene. In addition, SAR predicts further isomerization reactions that would be competitive with bimolecular RO2 reactions for chemical conditions that are typical for forested environments with low concentrations of nitric oxide. Assuming that OH peroxy radicals can rapidly interconvert by addition and elimination of O2 like in isoprene, bulk isomerization rate constants of 0.21 and 0.097ĝ€¯s-1 (TCombining double low line298ĝ€¯K) for the three isomers resulting from the 3′-OH and 1-OH addition, respectively, can be derived from SAR. Measurements of radicals and trace gases in the experiments allowed us to calculate radical production and destruction rates, which are expected to be balanced. The largest discrepancies between production and destruction rates were found for RO2. Additional loss of organic peroxy radicals due to isomerization reactions could explain the observed discrepancies. The uncertainty of the total radical (ROxCombining double low lineOH+HO2+RO2) production rates was high due to the uncertainty in the yield of radicals from myrcene ozonolysis. However, results indicate that radical production can only be balanced if the reaction rate constant of the reaction between hydroperoxy (HO2) and RO2 radicals derived from myrcene is lower (0.9 to 1.6×10-11ĝ€¯cm3s-1) than predicted by SAR. Another explanation of the discrepancies would be that a significant fraction of products (yield: 0.3 to 0.6) from these reactions include OH and HO2 radicals instead of radical-terminating organic peroxides. Experiments also allowed us to determine the yields of organic oxidation products acetone (yield: 0.45±0.08) and formaldehyde (yield: 0.35±0.08). Acetone and formaldehyde are produced from different oxidation pathways, so that yields of these compounds reflect the branching ratios of the initial OH addition to myrcene. Yields determined in the experiments are consistent with branching ratios expected from SAR. The yield of organic nitrate was determined from the gas-phase budget analysis of reactive oxidized nitrogen in the chamber, giving a value of 0.13±0.03. In addition, the reaction rate constant for myrceneĝ€¯+ĝ€¯OH was determined from the measured myrcene concentration, yielding a value of (2.3±0.3)×10-10ĝ€¯cm3s-1. © 2021 Zhaofeng Tan et al.
语种	英语
scopus关键词	atmospheric chemistry; concentration (composition); monoterpene; oxidation; photochemistry; photooxidation; radical; reaction kinetics; uncertainty analysis
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/246470
作者单位	Institute of Energy and Climate Research, Troposphere (IEK-8), Forschungszentrum Jülich GmbH, Jülich, Germany; Department 5 - Method Standardisation, Reference Laboratories, Resistance to Antibiotics, Federal Office of Consumer Protection and Food Safety, Berlin, Germany; Institute of Nutrition and Food Sciences, Food Science, University of Bonn, Bonn, Germany; State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing, China; European University of Applied Sciences, Brühl, Germany
推荐引用方式 GB/T 7714	Tan Z.,Hantschke L.,Kaminski M.,et al. Atmospheric photo-oxidation of myrcene: OH reaction rate constant, gas-phase oxidation products and radical budgets[J],2021,21(20).
APA	Tan Z..,Hantschke L..,Kaminski M..,Acir I.-H..,Bohn B..,...&Fuchs H..(2021).Atmospheric photo-oxidation of myrcene: OH reaction rate constant, gas-phase oxidation products and radical budgets.ATMOSPHERIC CHEMISTRY AND PHYSICS,21(20).
MLA	Tan Z.,et al."Atmospheric photo-oxidation of myrcene: OH reaction rate constant, gas-phase oxidation products and radical budgets".ATMOSPHERIC CHEMISTRY AND PHYSICS 21.20(2021).