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Molecular rearrangement of bicyclic peroxy radicals is a key route to aerosol from aromatics.

Siddharth IyerAvinash KumarAnni SavolainenShawon BaruaChristopher David DaubLukas PichelstorferPontus RoldinOlga GarmashPrasenjit SealTheo KurténMatti P Rissanen
Published in: Nature communications (2023)
The oxidation of aromatics contributes significantly to the formation of atmospheric aerosol. Using toluene as an example, we demonstrate the existence of a molecular rearrangement channel in the oxidation mechanism. Based on both flow reactor experiments and quantum chemical calculations, we show that the bicyclic peroxy radicals (BPRs) formed in OH-initiated aromatic oxidation are much less stable than previously thought, and in the case of the toluene derived ipso-BPRs, lead to aerosol-forming low-volatility products with up to 9 oxygen atoms on sub-second timescales. Similar results are predicted for ipso-BPRs formed from many other aromatic compounds. This reaction class is likely a key route for atmospheric aerosol formation, and including the molecular rearrangement of BPRs may be vital for accurate chemical modeling of the atmosphere.
Keyphrases
  • water soluble
  • hydrogen peroxide
  • molecular dynamics
  • single molecule
  • particulate matter
  • electron transfer
  • density functional theory
  • high resolution
  • molecular dynamics simulations
  • mass spectrometry
  • monte carlo