title: Formation of methane sulfinic acid in the gas-phase OH-radical initiated oxidation of dimethyl sulfoxide.
abstract: Dimethyl sulfoxide (CH3S(O)CH3: DMSO) is an important product of dimethyl sulfide (CH3SCH3: DMS) photooxidation. The mechanism of the OH-radical initiated oxidation of DMSO is still highly uncertain and a major aim of recent studies has been to establish if methane sulfinic acid (CH3S(O)OH: MSIA) is a major reaction product In the present work the products of the OH-radical gas-phase oxidation of dimethyl sulfoxide have been investigated in the absence and presence of NOx All experiments were performed in a 1,080 L reaction chamber in 1,000 mbar synthetic air at 284 +/- 2 K using long-path FT-IR spectroscopy and ion chromatography to monitor and quantify reactants and reaction products. Formation of methane sulfinic acid in high yield (80-99%) was observed in both in the absence and presence of NOx, and the results support that it is the major primary reaction product Other products observed included dimethyl sulfone (CH3S(O)2CH3: DMSO2), sulfur dioxide (SO2), methane sulfonic acid (CH3S(O)2OH: MSA), and methane sulfonyl peroxynitrate (CH3S(O)2OONO2: MSPN). The formation behavior of these products is in line with their source being mainly secondary production via oxidation of a primary product, i.e. MSIA.
authors.affiliation: Physikalische Chemie/F9B, Bergische Universität-GH Wuppertal, Gauss Strasse 20, D-42097 Wuppertal, Germany.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Arsene
authors.forename: Ian
authors.initials: I
authors.lastname: Barnes
authors.forename: Karl H
authors.initials: KH
authors.lastname: Becker
authors.forename: William F
authors.initials: WF
authors.lastname: Schneider
authors.forename: Timothy T
authors.initials: TT
authors.lastname: Wallington
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Mihalopoulos
authors.forename: Iulia V
authors.initials: IV
authors.lastname: Patroescu-Klotz
mesh_terms: D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D012997:Solvents / Q000737:chemistry*; D013441:Sulfinic Acids / Q000737:chemistry*
chemical_list: D016877:Oxidants; D012997:Solvents; D013441:Sulfinic Acids; C053310:methanesulfinic acid; D017665:Hydroxyl Radical; D004121:Dimethyl Sulfoxide