Formation of Organic Acids and Carbonyl Compounds in n-Butane Oxidation via γ-Ketohydroperoxide Decomposition

Denisia M Popolan-Vaida; Arkke J Eskola; Brandon Rotavera; Jessica F Lockyear; Zhandong Wang; S Mani Sarathy; Rebecca L Caravan; Judit Zádor; Leonid Sheps; Arnas Lucassen; Kai Moshammer; Philippe Dagaut; David L Osborn; Nils Hansen; Stephen R Leone; Craig A Taatjes

doi:10.1002/anie.202209168

Formation of Organic Acids and Carbonyl Compounds in n-Butane Oxidation via γ-Ketohydroperoxide Decomposition

Angew Chem Int Ed Engl. 2022 Oct 17;61(42):e202209168. doi: 10.1002/anie.202209168. Epub 2022 Sep 14.

Authors

Denisia M Popolan-Vaida^{1

2}, Arkke J Eskola^{3

4}, Brandon Rotavera^{3

5}, Jessica F Lockyear¹, Zhandong Wang^{6

7}, S Mani Sarathy⁶, Rebecca L Caravan^{3

8}, Judit Zádor³, Leonid Sheps³, Arnas Lucassen^{3

9}, Kai Moshammer^{3

9}, Philippe Dagaut¹⁰, David L Osborn³, Nils Hansen³, Stephen R Leone¹, Craig A Taatjes³

Affiliations

¹ Department of Chemistry and Physics, University of California, Berkeley, Berkeley, CA 94720, USA.
² Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA.
³ Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA.
⁴ Department of Chemistry, University of Helsinki, 00014, Helsinki, Finland.
⁵ Department of Chemistry and College of Engineering, University of Georgia, Athens, GA 30602, USA.
⁶ King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center (CCRC), Thuwal, 23955-6900, Saudi Arabia.
⁷ National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.
⁸ Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
⁹ Physikalisch-Technische Bundesanstalt, 38116, Braunschweig, Germany.
¹⁰ Centre National de la Recherche Scientifique (CNRS), INSIS, ICARE, 45071, Orléans Cedex 2, France.

PMID: 35895936
DOI: 10.1002/anie.202209168

Abstract

A crucial chain-branching step in autoignition is the decomposition of ketohydroperoxides (KHP) to form an oxy radical and OH. Other pathways compete with chain-branching, such as "Korcek" dissociation of γ-KHP to a carbonyl and an acid. Here we characterize the formation of a γ-KHP and its decomposition to formic acid+acetone products from observations of n-butane oxidation in two complementary experiments. In jet-stirred reactor measurements, KHP is observed above 590 K. The KHP concentration decreases with increasing temperature, whereas formic acid and acetone products increase. Observation of characteristic isotopologs acetone-d₃ and formic acid-d₀ in the oxidation of CH₃ CD₂ CD₂ CH₃ is consistent with a Korcek mechanism. In laser-initiated oxidation experiments of n-butane, formic acid and acetone are produced on the timescale of KHP removal. Modelling the time-resolved production of formic acid provides an estimated upper limit of 2 s^-1 for the rate coefficient of KHP decomposition to formic acid+acetone.

Keywords: Autoignition; Hydrocarbon Oxidation; Ketohydroperoxides; Korcek Reaction; Photoionization.

Abstract

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