title: Kinetics of the reactions of OH radicals with 2- and 3-methylfuran, 2,3- and 2,5-dimethylfuran, and E- and Z-3-hexene-2,5-dione, and products of OH + 2,5-dimethylfuran.
abstract: Furan and alkylfurans are present in the atmosphere from direct emissions and in situ formation from other volatile organic compounds. The OH radical-initiated reactions of furan and alkylfurans have been proposed as relatively clean in situ sources of unsaturated 1,4-dicarbonyls, some of which are otherwise not readily available. Using a relative rate method, rate constants at 296 ± 2 K for the gas-phase reactions of OH radicals with 2- and 3-methylfuran, 2,3- and 2,5-dimethylfuran, and Z- and E-3-hexene-2,5-dione have been measured, of (in units of 10(-11) cm(3) molecule(-1) s(-1)): 2-methylfuran, 7.31 ± 0.35; 3-methylfuran, 8.73 ± 0.18; 2,3-dimethylfuran, 12.6 ± 0.4; 2,5-dimethylfuran, 12.5 ± 0.4; Z-3-hexene-2,5-dione, 5.90 ± 0.57; and E-3-hexene-2,5-dione, 4.14 ± 0.02. Products of the OH radical-initiated reaction of 2,5-dimethylfuran were investigated, with 3-hexene-2,5-dione being formed with molar yields of 24 ± 3% in the presence of NO and 34 ± 3% in the absence of NO. Direct air sampling atmospheric pressure ionization mass spectrometry showed the formation of additional products of molecular weight 114, attributed to CH(3)C(O)CH ═ CHC(O)OH and/or 5-hydroxy-5-methyl-2-furanone, and 128, attributed to CH(3)C(O)OC(CH(3)) = CHCHO.
authors.affiliation: Air Pollution Research Center, University of California , Riverside, California 92521, United States.
authors.forename: Sara M
authors.initials: SM
authors.lastname: Aschmann
authors.forename: Noriko
authors.initials: N
authors.lastname: Nishino
authors.forename: Janet
authors.initials: J
authors.lastname: Arey
authors.forename: Roger
authors.initials: R
authors.lastname: Atkinson
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry*; D001272:Atmosphere / Q000737:chemistry; D005663:Furans / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D055549:Volatile Organic Compounds / Q000737:chemistry*
chemical_list: C452622:3-hexene-2,5-dione; D000393:Air Pollutants; D000475:Alkenes; D005663:Furans; D055549:Volatile Organic Compounds; D017665:Hydroxyl Radical; C029060:2-methylfuran; C039851:3-methylfuran; C037555:2,5-dimethylfuran