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Experimental Evidence of Dioxole Unimolecular Decay Pathway for Isoprene-Derived Criegee Intermediates

Vansco, Michael F. and Caravan, Rebecca L. and Zuraski, Kristen and Winiberg, Frank A. F. and Au, Kendrew and Trongsiriwat, Nisalak and Walsh, Patrick J. and Osborn, David L. and Percival, Carl J. and Khan, M. Anwar H. and Shallcross, Dudley E. and Taatjes, Craig A. and Lester, Marsha I. (2020) Experimental Evidence of Dioxole Unimolecular Decay Pathway for Isoprene-Derived Criegee Intermediates. Journal of Physical Chemistry A, 124 (18). pp. 3542-3554. ISSN 1089-5639. https://resolver.caltech.edu/CaltechAUTHORS:20200409-112034815

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Abstract

Ozonolysis of isoprene, one of the most abundant volatile organic compounds emitted into the Earth’s atmosphere, generates two four-carbon unsaturated Criegee intermediates, methyl vinyl ketone oxide (MVK-oxide) and methacrolein oxide (MACR-oxide). The extended conjugation between the vinyl substituent and carbonyl oxide groups of these Criegee intermediates facilitates rapid electrocyclic ring closures that form five-membered cyclic peroxides, known as dioxoles. This study reports the first experimental evidence of this novel decay pathway, which is predicted to be the dominant atmospheric sink for specific conformational forms of MVK-oxide (anti) and MACR-oxide (syn) with the vinyl substituent adjacent to the terminal O atom. The resulting dioxoles are predicted to undergo rapid unimolecular decay to oxygenated hydrocarbon radical products, including acetyl, vinoxy, formyl, and 2-methylvinoxy radicals. In the presence of O₂, these radicals rapidly react to form peroxy radicals (ROO), which quickly decay via carbon-centered radical intermediates (QOOH) to stable carbonyl products that were identified in this work. The carbonyl products were detected under thermal conditions (298 K, 10 Torr He) using multiplexed photoionization mass spectrometry (MPIMS). The main products (and associated relative abundances) originating from unimolecular decay of anti-MVK-oxide and subsequent reaction with O₂ are formaldehyde (88 ± 5%), ketene (9 ± 1%), and glyoxal (3 ± 1%). Those identified from the unimolecular decay of syn-MACR-oxide and subsequent reaction with O₂ are acetaldehyde (37 ± 7%), vinyl alcohol (9 ± 1%), methylketene (2 ± 1%), and acrolein (52 ± 5%). In addition to the stable carbonyl products, the secondary peroxy chemistry also generates OH or HO₂ radical coproducts.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acs.jpca.0c02138DOIArticle
ORCID:
AuthorORCID
Osborn, David L.0000-0003-4304-8218
Taatjes, Craig A.0000-0002-9271-0282
Additional Information:© 2020 American Chemical Society. Received: March 12, 2020; Revised: April 7, 2020; Published: April 7, 2020. This research was supported by the U.S. Department of Energy (USDOE), Office of Basic Energy Sciences (BES), under Grant DE-FG02-87ER13792 (M.I.L.). This material is also based upon work supported by the Division of Chemical Sciences, Geosciences, and Biosciences, BES, USDOE. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the USDOE’s National Nuclear Security Administration under Contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the USDOE or the United States Government. This material is based in part on research at Argonne National Laboratory supported by the USDOE, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under Contract DE-AC02-06CH11357. The Advanced Light Source is supported by the Director, Office of Science, BES/USDOE, under Contract DE-AC02-05CH11231 at Lawrence Berkeley National Laboratory. This research was carried out in part by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA), supported by the Upper Atmosphere Research and Tropospheric Chemistry Program. The contributions of R.L.C. and K.Z. were supported in part by appointments to the NASA Postdoctoral Program at the NASA Jet Propulsion Laboratory, administered by the Universities Space Research Association under contract with NASA. P.J.W. thanks the NSF (CHE-1902509). D.E.S. and M.A.H.K. thank NERC (grant codes NE/K004905/1), Bristol ChemLabS, and the Primary Science Teaching Trust, under whose auspices various aspects of this work were funded. The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-87ER13792
Department of Energy (DOE)DE-NA0003525
Department of Energy (DOE)DE-AC02-06CH11357
Department of Energy (DOE)DE-AC02-05CH11231
NASA/JPL/CaltechUNSPECIFIED
NASA Postdoctoral ProgramUNSPECIFIED
NSFCHE-1902509
Natural Environment Research Council (NERC)NE/K004905/1
Bristol ChemLabSUNSPECIFIED
Primary Science Teaching TrustUNSPECIFIED
Issue or Number:18
Record Number:CaltechAUTHORS:20200409-112034815
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200409-112034815
Official Citation:Experimental Evidence of Dioxole Unimolecular Decay Pathway for Isoprene-Derived Criegee Intermediates. Michael F. Vansco, Rebecca L. Caravan, Kristen Zuraski, Frank A. F. Winiberg, Kendrew Au, Nisalak Trongsiriwat, Patrick J. Walsh, David L. Osborn, Carl J. Percival, M. Anwar H. Khan, Dudley E. Shallcross, Craig A. Taatjes, and Marsha I. Lester. The Journal of Physical Chemistry A 2020 124 (18), 3542-3554 DOI: 10.1021/acs.jpca.0c02138
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:102436
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Apr 2020 18:33
Last Modified:11 May 2020 21:38

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