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Acetonyl Peroxy and Hydro Peroxy Self- and Cross- Reactions: Kinetics, Mechanism, and Chaperone Enhancement from the Perspective of the Hydroxyl Radical Product

Zuraski, Kristen and Hui, Aileen O. and Grieman, Fred J. and Darby, Emily and Møller, Kristian H. and Winiberg, Frank A. F. and Percival, Carl J. and Smarte, Matthew D. and Okumura, Mitchio and Kjaergaard, Henrik G. and Sander, Stanley P. (2020) Acetonyl Peroxy and Hydro Peroxy Self- and Cross- Reactions: Kinetics, Mechanism, and Chaperone Enhancement from the Perspective of the Hydroxyl Radical Product. Journal of Physical Chemistry A . ISSN 1089-5639. (In Press) https://resolver.caltech.edu/CaltechAUTHORS:20200831-130459139

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Abstract

Pulsed laser photolysis coupled with infrared (IR) wavelength modulation spectroscopy and ultraviolet (UV) absorption spectroscopy was used to study the kinetics and branching fractions for the acetonyl peroxy (CH₃C(O)CH₂O₂) self-reaction and its reaction with hydro peroxy (HO₂) at a temperature of 298 K and pressure of 100 Torr. Near-IR and mid-IR lasers simultaneously monitored HO₂ and hydroxyl, OH, respectively, while UV absorption measurements monitored the CH₃C(O)CH₂O₂ concentrations. The overall rate constant for the reaction between CH₃C(O)CH₂O₂ and HO₂ was found to be (5.5 ± 0.5) × 10⁻¹² cm³ molecule⁻¹ s⁻¹ and the branching fraction for OH yield from this reaction was directly measured as 0.30 ± 0.04. The CH₃C(O)CH₂O₂ self-reaction rate constant was measured to be (4.8 ± 0.8) × 10⁻¹² cm³ molecule⁻¹ s⁻¹ and the branching fraction for alkoxy formation was inferred from secondary chemistry as 0.33 ± 0.13. An increase in the rate of the HO₂ self-reaction was also observed as a function of acetone (CH₃C(O)CH₃) concentration which is interpreted as a chaperone effect resulting from hydrogen-bond complexation between HO₂ and CH₃C(O)CH₃. The chaperone enhancement coefficient for CH₃C(O)CH₃ was determined to be k”A = (4.0 ± 0.2) x 10⁻²⁹ cm⁶ molecule⁻² s⁻¹ and the equilibrium constant for HO₂•CH₃C(O)CH₃ complex formation was found to be K_c(R15) = (2.0 ± 0.89) × 10⁻¹⁸ cm³ molecule⁻¹; from these values the rate constant for the HO₂ + HO₂•CH₃C(O)CH₃ reaction was estimated to be (2 ± 1) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹. Results from UV absorption cross-section measurements of CH₃C(O)CH₂O₂ and prompt OH radical yields arising from possible oxidation of the CH₃C(O)CH₃-derived alkyl radical are also discussed. Using theoretical methods, no likely pathways for the observed prompt OH radical formation have been found and thus remains unexplained.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acs.jpca.0c06220DOIArticle
ORCID:
AuthorORCID
Okumura, Mitchio0000-0001-6874-1137
Kjaergaard, Henrik G.0000-0002-7275-8297
Sander, Stanley P.0000-0003-1424-3620
Additional Information:© 2020 American Chemical Society. Publication Date: August 27, 2020. This research was carried out 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 Programs. The contribution of K.Z. was supported by the appointment to the NASA Postdoctoral Program at the NASA Jet Propulsion Laboratory, administered by the Universities Space Research Association under contract with NASA. The contribution from A.H. was supported in part by the National Science Foundation (NSF Grant No. CHE-1413712), and the NASA Earth and Science Fellowship (NESSF). M.D.S. was supported by the NASA Earth and Space Science Fellowship (NNX16AO36H). This research was also supported by an appointment of F.J.G. to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, administered by Oak Ridge Associated Universities through a contract with NASA and a SURP grant from Pomona College for E.D. The work by HGK was funded by the Independent Research Fund Denmark. Author contributions: S.S. and M.O. conceived and designed the research. K.Z. conducted the experiments and performed the data analysis. F.A.F. assisted with the IRKS instrumental upgrades. C.J.P. helped with experimental planning and the model mechanism. A.O.H., F.J.G., and E.D. conducted the early experiments and F.J.G. performed the data analysis on the part of that work presented here. M.D.S. wrote the original kinetic analysis library. K.H.M. and H.G.K. contributed the RRKM-ME and MESMER modeling work. K.Z. and F.G. wrote the paper. All authors contributed to the scientific discussion and preparation of the manuscript.
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
NASA Postdoctoral ProgramUNSPECIFIED
NSFCHE-1413712
NASA Earth and Space Science FellowshipNNX16AO36H
Pomona CollegeUNSPECIFIED
Independent Research Fund DenmarkUNSPECIFIED
Record Number:CaltechAUTHORS:20200831-130459139
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200831-130459139
Official Citation:Acetonyl Peroxy and Hydro Peroxy Self- and Cross- Reactions: Kinetics, Mechanism, and Chaperone Enhancement from the Perspective of the Hydroxyl Radical Product. Kristen Zuraski, Aileen O. Hui, Fred J. Grieman, Emily Darby, Kristian H. Møller, Frank A. F. Winiberg, Carl J. Percival, Matthew D. Smarte, Mitchio Okumura, Henrik Grum Kjaergaard, and Stanley P Sander. The Journal of Physical Chemistry A. Just Accepted Manuscript; DOI: 10.1021/acs.jpca.0c06220
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105173
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Sep 2020 23:33
Last Modified:08 Sep 2020 23:33

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