Oxidation of aromatic and aliphatic hydrocarbons by OH radicals photochemically generated from H2O2 in ice.
Oxidation of aromatic and saturated aliphatic hydrocarbons (c = 10(-3)-10(-5) mol L(-1)) by the hydroxyl radicals, photochemically produced from hydrogen peroxide (c = 10(-1)-10(-5) mol L(-1)), in frozen aqueous solutions was investigated in the temperature range of -20 to -196 degrees C. While aromatic molecules (benzene, phenol, naphthalene, naphthalen-2-ol, or anthracene) underwent primarily addition-elimination reactions to form the corresponding hydroxy compounds, saturated hydrocarbons (cyclohexane, butane, methane) were oxidized to alcohols or carbonyl compounds via hydrogen abstraction and termination reactions. The results suggest that these photoreactions, taking place in a highly concentrated liquid or solidified layers covering the ice crystals, are qualitatively similar to those known to occur in liquid aqueous solutions; however, that probability of any bimolecular reaction in the environment ultimately depends on organic contaminant concentrations and oxidants availability at specific locations of the ice matrix, temperature, wavelength, and photon flux. They, moreover, support hypotheses that oxidation of organic impurities in the snowpack can produce volatile hydroxy and carbonyl compounds, which may consequently be released to the atmosphere.
Dolinová
Jindriska
J
RECETOX, Masaryk University, Kamenice 126/3, 625 00 Brno, Czech Republic.
Rozicka
Radovan
R
Kurková
Romana
R
Klánová
Jana
J
Klán
Petr
P
D002851:Chromatography, High Pressure Liquid; D006838:Hydrocarbons / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D007053:Ice / Q000032:analysis*; D010084:Oxidation-Reduction; D010777:Photochemistry
D006838:Hydrocarbons; D007053:Ice; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide