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

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 γ-KHP a carbonyl acid. Here we characterize formation its formic acid+acetone products from observations n-butane oxidation two complementary experiments. In jet-stirred reactor measurements, KHP observed above 590 K. The concentration decreases increasing temperature, whereas acid acetone increase. Observation characteristic isotopologs acetone-d3 acid-d0 CH3CD2CD2CH3 consistent Korcek mechanism. laser-initiated experiments n-butane, are produced on timescale removal. Modelling time-resolved production provides estimated upper limit 2 s−1 for rate coefficient acid+acetone.