title: Investigation of the role of bicyclic peroxy radicals in the oxidation mechanism of toluene.
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.
authors.affiliation: Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, USA.
authors.forename: Adam W
authors.initials: AW
authors.lastname: Birdsall
authors.forename: John F
authors.initials: JF
authors.lastname: Andreoni
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Elrod
mesh_terms: D001643:Bridged Bicyclo Compounds / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*; D014050:Toluene / Q000737:chemistry*
chemical_list: D001643:Bridged Bicyclo Compounds; D010545:Peroxides; D017665:Hydroxyl Radical; D014050:Toluene