Details

Autor(en) / Beteiligte

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

Titel

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

Ist Teil von

• Angewandte Chemie (International ed.), 2022-10, Vol.61 (42), p.e202209168-n/a

Auflage

International ed. in English

Ort / Verlag

Weinheim: Wiley Subscription Services, Inc

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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 CH3CD2CD2CH3 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. High‐resolution mass spectrometry in conjunction with single photon tunable synchrotron radiation provides clear experimental evidence of organic acids and carbonyl formation from γ‐ketohydroperoxide decomposition via the Korcek mechanism. These results provide experimental and computational bounds that enable the construction of more realistic and accurate chemical kinetic mechanisms for autoignition chemistry.