INFRARED MATRIX-ISOLATION STUDIES OF THE REACTIONS OF DICHLOROMETHANE AND DIBROMOMETHANE WITH ATOMIC OXYGEN

The reactions of atomic oxygen with CH2Cl2 and CH2Br2 trapped in argon matrices have been studied by FTIR spectroscopy. O(1D) and (O(3P))-P-3 were generated in situ by UV photolysis of co-deposited ozone. Products were identified by employing O-18 and scrambled O-18/O-16 ozone as well as deuterated methylene halides. Kinetic studies performed on both CH2Cl2 and CH2Br2 With O(1D) under the same experimental conditions allowed the reaction pathways to be determined. With CH2Br2 as parent molecule, three routes were evident leading to (i) CHOBr, (ii) CO...(HBr)2, and (iii) CH2O. With CH2Cl2 as parent molecule, only the first two channels were observed. Carbonyl compounds rapidly decomposed under irradiation, and CO...(HX)2 was also produced as a secondary species.