56240-83-6Relevant articles and documents
Conversion of SO2 to SO3 Facilitated by in Situ UV Photolysis of H2CO and SO2 in an O2 Matrix at 12 K
Green, Martina,Lee, Edward K. C.
, p. 6470 - 6475 (2007/10/02)
The photooxidation product distributions observed in photolyses of H2CO and H2CO*SO2 molecular complexes in O2 matrices at λ = 270-420 nm are compared.Photodissociation of H2CO produces RO2 species, i.e., HO2 and HC(O)OO radicals, which then efficiently oxidize SO2 to SO3 (and H2SO4).This process occurs with an efficiency of ca. 0.7 +/- 0.3 per H2CO*SO2 molecular complex photodissociated.Various photooxidation mechanisms are considered.Implications of the low-temperature/matrix photooxidation results on atmospheric photooxidation of SO2 by RO2 species are discussed.
Photooxidation of Formaldehyde in Solid Oxygen and Argon/Oxygen Matrices at 12 K
Diem, Michael,Lee, Edward K. C.
, p. 4507 - 4512 (2007/10/02)
Matrix-isolated formaldehyde in solid O2, Ar/O2, and Ar matrices at 12 K has been photolyzed by ultraviolet light in the 220 - 400 nm range.The photoproducts were identified by infrared spectroscopy.Stable oxidation products were CO, CO2, H2O, H2O2, O3, and HCOOH, whereas relatively unstable products were HO2, its hydrogen-bonded dimer (HO2)2, formylperoxy radical HC(O)OO, and performic acid.The observed photoproduct distribution is rationalized by the stoichiometry of chemical reactions involving one C atom, two H atoms, and odd numbers of O atoms in the cage.Photolysis of the Ar/O2/H2CO sample (10 percent O2 in solid Ar) gave poor yields of radical species.Under the experimental conditions employed, the photochemical oxidation process is not driven to completion, and therefore it is possible to trap reactive intermediates for spectroscopic and kinetic studies.Photodissociation threshold of H2CO and (H2CO)2 in solid Ar have been measured with tunable, pulsed UV laser photolysis to show that (H2CO)2 has a lower treshold than H2CO.
