Investigation of the role of bicyclic peroxy radicals in the oxidation mechanism of toluene

J Phys Chem A. 2010 Oct 7;114(39):10655-63. doi: 10.1021/jp105467e.

Abstract

The products of the primary OH-initiated oxidation of toluene were investigated using the turbulent flow chemical ionization mass spectrometry technique under different oxygen, NO, and initial OH radical concentrations as well as a range of total pressures. The bicyclic peroxy radical intermediate, a key proposed intermediate species in the Master Chemical Mechanism (MCM) for the atmospheric oxidation of toluene, was detected for the first time. The toluene oxidation mechanism was shown to have a strong oxygen concentration dependence, presumably due to the central role of the bicyclic peroxy radical in determining the stable product distribution at atmospheric oxygen concentrations. The results also suggest a potential role for bicyclic peroxy radical + HO(2) reactions at high HO(2)/NO ratios. These reactions are postulated to be a source of the inconsistencies between environmental chamber results and predictions from the MCM.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Bridged Bicyclo Compounds / chemistry*
  • Hydroxyl Radical / chemistry*
  • Oxidation-Reduction
  • Peroxides / chemistry*
  • Toluene / chemistry*

Substances

  • Bridged Bicyclo Compounds
  • Peroxides
  • Hydroxyl Radical
  • Toluene