Directly measuring reaction kinetics of (center dot)QOOH - a crucial but elusive intermediate in hydrocarbon autoignition

• Hydrocarbon autoignition has long been an area of intense fundamental chemical interest, and is a key technological process for emerging clean and efficient combustion strategies. Carbon-centered radicals containing an -OOH group, commonly denoted (center dot)QOOH radicals, are produced by isomerization of the alkylperoxy radicals that are formed in the first stages of oxidation. These (center dot)QOOH radicals are among the most critical species for modeling autoignition, as their reactions with O-2 are responsible for chain branching below 1000 K. Despite their importance, no (center dot)QOOH radicals have ever been observed by any means, and only computational and indirect experimental evidence has been available on their reactivity. Here, we directly produce a (center dot)QOOH radical, 2-hydroperoxy-2-methylprop-1-yl, and experimentally determine rate coefficients for its unimolecular decomposition and its association reaction with O-2. The results are supported by high-level theoretical kinetics calculations. Our experimental strategy opens up a new avenue to study the chemistry of (center dot)QOOH radicals in isolation.

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NATURVETENSKAP  -- Fysik -- Atom- och molekylfysik och optik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Atom and Molecular Physics and Optics (hsv//eng)

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