Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism

Fangfang Ma; Xirui Guo; Deming Xia; Hong Bin Xie; Yonghong Wang; Jonas Elm; Jingwen Chen; Junfeng Niu

doi:10.1021/acs.est.0c07925

Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism

Fangfang Ma, Xirui Guo, Deming Xia, Hong Bin Xie^*, Yonghong Wang, Jonas Elm, Jingwen Chen, Junfeng Niu

^*Corresponding author for this work

Department of Chemistry
iCLIMATE Aarhus University Interdisciplinary Centre for Climate Change - iCLIMATE Aarhus University Interdisciplinary Centre for Climate Change, Langelandsgade

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29 Citations (Scopus)

Abstract

The atmospheric chemistry of isoprene has broad implications for regional air quality and the global climate. Allylic radicals, taking 13-17% yield in the isoprene oxidation by •Cl, can contribute as much as 3.6-4.9% to all possible formed intermediates in local regions at daytime. Considering the large quantity of isoprene emission, the chemistry of the allylic radicals is therefore highly desirable. Here, we investigated the atmospheric oxidation mechanism of the allylic radicals using quantum chemical calculations and kinetics modeling. The results indicate that the allylic radicals can barrierlessly combine with O2 to form peroxy radicals (RO2•). Under ≤100 ppt NO and ≤50 ppt HO2• conditions, the formed RO2• mainly undergo two times "successive cyclization and O2 addition"to finally form the product fragments 2-alkoxy-acetaldehyde (C2H3O2•) and 3-hydroperoxy-2-oxopropanal (C3H4O4). The presented reaction illustrates a novel successive cyclization-driven autoxidation mechanism. The formed 3-hydroperoxy-2-oxopropanal product is a new isomer of the atmospheric C3H4O4 family and a potential aqueous-phase secondary organic aerosol precursor. Under >100 ppt NO condition, NO can mediate the cyclization-driven autoxidation process to form C5H7NO3, C5H7NO7, and alkoxy radical-related products. The proposed novel autoxidation mechanism advances our current understanding of the atmospheric chemistry of both isoprene and RO2•.

Original language	English
Journal	Environmental Science & Technology
Volume	55
Issue	8
Pages (from-to)	4399-4409
Number of pages	11
ISSN	0013-936X
DOIs	https://doi.org/10.1021/acs.est.0c07925
Publication status	Published - Apr 2021

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10.1021/acs.est.0c07925

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@article{298ae7002c7d4fe69495ff5148bba65e,

title = "Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism",

abstract = "The atmospheric chemistry of isoprene has broad implications for regional air quality and the global climate. Allylic radicals, taking 13-17% yield in the isoprene oxidation by •Cl, can contribute as much as 3.6-4.9% to all possible formed intermediates in local regions at daytime. Considering the large quantity of isoprene emission, the chemistry of the allylic radicals is therefore highly desirable. Here, we investigated the atmospheric oxidation mechanism of the allylic radicals using quantum chemical calculations and kinetics modeling. The results indicate that the allylic radicals can barrierlessly combine with O2 to form peroxy radicals (RO2•). Under ≤100 ppt NO and ≤50 ppt HO2• conditions, the formed RO2• mainly undergo two times {"}successive cyclization and O2 addition{"}to finally form the product fragments 2-alkoxy-acetaldehyde (C2H3O2•) and 3-hydroperoxy-2-oxopropanal (C3H4O4). The presented reaction illustrates a novel successive cyclization-driven autoxidation mechanism. The formed 3-hydroperoxy-2-oxopropanal product is a new isomer of the atmospheric C3H4O4 family and a potential aqueous-phase secondary organic aerosol precursor. Under >100 ppt NO condition, NO can mediate the cyclization-driven autoxidation process to form C5H7NO3, C5H7NO7, and alkoxy radical-related products. The proposed novel autoxidation mechanism advances our current understanding of the atmospheric chemistry of both isoprene and RO2•. ",

author = "Fangfang Ma and Xirui Guo and Deming Xia and Xie, {Hong Bin} and Yonghong Wang and Jonas Elm and Jingwen Chen and Junfeng Niu",

note = "Funding Information: The authors thank Dr. Mikael Ehn (University of Helsinki) for the discussion. This study was supported by the LiaoNing Revitalization Talents Program (XLYC1907194), the National Natural Science Foundation of China (21876024, 21677028), the Major International (Regional) Joint Research Project (21661142001), the Fundamental Research Funds for the Central Universities (DUT19LK47), and Supercomputing Center of Dalian University of Technology. Additional support for this research was provided by the Texas A&M University Supercomputing Facilities and the Laboratory for Molecular Simulations at Texas A&M University. F.M. thanks the China Scholarship Council (no. 201906060087) Publisher Copyright: {\textcopyright} 2021 American Chemical Society. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.",

year = "2021",

month = apr,

doi = "10.1021/acs.est.0c07925",

language = "English",

volume = "55",

pages = "4399--4409",

journal = "Environmental Science & Technology",

issn = "0013-936X",

publisher = "American Chemical Society",

number = "8",

}

Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism. / Ma, Fangfang; Guo, Xirui; Xia, Deming et al.
In: Environmental Science & Technology, Vol. 55, No. 8, 04.2021, p. 4399-4409.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

TY - JOUR

T1 - Atmospheric Chemistry of Allylic Radicals from Isoprene

T2 - A Successive Cyclization-Driven Autoxidation Mechanism

AU - Ma, Fangfang

AU - Guo, Xirui

AU - Xia, Deming

AU - Xie, Hong Bin

AU - Wang, Yonghong

AU - Elm, Jonas

AU - Chen, Jingwen

AU - Niu, Junfeng

N1 - Funding Information: The authors thank Dr. Mikael Ehn (University of Helsinki) for the discussion. This study was supported by the LiaoNing Revitalization Talents Program (XLYC1907194), the National Natural Science Foundation of China (21876024, 21677028), the Major International (Regional) Joint Research Project (21661142001), the Fundamental Research Funds for the Central Universities (DUT19LK47), and Supercomputing Center of Dalian University of Technology. Additional support for this research was provided by the Texas A&M University Supercomputing Facilities and the Laboratory for Molecular Simulations at Texas A&M University. F.M. thanks the China Scholarship Council (no. 201906060087) Publisher Copyright: © 2021 American Chemical Society. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/4

Y1 - 2021/4

N2 - The atmospheric chemistry of isoprene has broad implications for regional air quality and the global climate. Allylic radicals, taking 13-17% yield in the isoprene oxidation by •Cl, can contribute as much as 3.6-4.9% to all possible formed intermediates in local regions at daytime. Considering the large quantity of isoprene emission, the chemistry of the allylic radicals is therefore highly desirable. Here, we investigated the atmospheric oxidation mechanism of the allylic radicals using quantum chemical calculations and kinetics modeling. The results indicate that the allylic radicals can barrierlessly combine with O2 to form peroxy radicals (RO2•). Under ≤100 ppt NO and ≤50 ppt HO2• conditions, the formed RO2• mainly undergo two times "successive cyclization and O2 addition"to finally form the product fragments 2-alkoxy-acetaldehyde (C2H3O2•) and 3-hydroperoxy-2-oxopropanal (C3H4O4). The presented reaction illustrates a novel successive cyclization-driven autoxidation mechanism. The formed 3-hydroperoxy-2-oxopropanal product is a new isomer of the atmospheric C3H4O4 family and a potential aqueous-phase secondary organic aerosol precursor. Under >100 ppt NO condition, NO can mediate the cyclization-driven autoxidation process to form C5H7NO3, C5H7NO7, and alkoxy radical-related products. The proposed novel autoxidation mechanism advances our current understanding of the atmospheric chemistry of both isoprene and RO2•.

AB - The atmospheric chemistry of isoprene has broad implications for regional air quality and the global climate. Allylic radicals, taking 13-17% yield in the isoprene oxidation by •Cl, can contribute as much as 3.6-4.9% to all possible formed intermediates in local regions at daytime. Considering the large quantity of isoprene emission, the chemistry of the allylic radicals is therefore highly desirable. Here, we investigated the atmospheric oxidation mechanism of the allylic radicals using quantum chemical calculations and kinetics modeling. The results indicate that the allylic radicals can barrierlessly combine with O2 to form peroxy radicals (RO2•). Under ≤100 ppt NO and ≤50 ppt HO2• conditions, the formed RO2• mainly undergo two times "successive cyclization and O2 addition"to finally form the product fragments 2-alkoxy-acetaldehyde (C2H3O2•) and 3-hydroperoxy-2-oxopropanal (C3H4O4). The presented reaction illustrates a novel successive cyclization-driven autoxidation mechanism. The formed 3-hydroperoxy-2-oxopropanal product is a new isomer of the atmospheric C3H4O4 family and a potential aqueous-phase secondary organic aerosol precursor. Under >100 ppt NO condition, NO can mediate the cyclization-driven autoxidation process to form C5H7NO3, C5H7NO7, and alkoxy radical-related products. The proposed novel autoxidation mechanism advances our current understanding of the atmospheric chemistry of both isoprene and RO2•.

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U2 - 10.1021/acs.est.0c07925

DO - 10.1021/acs.est.0c07925

M3 - Journal article

C2 - 33769798

AN - SCOPUS:85104942518

SN - 0013-936X

VL - 55

SP - 4399

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JO - Environmental Science & Technology

JF - Environmental Science & Technology

IS - 8

ER -

Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism

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