REACTION BETWEEN ATOMIC OXYGEN AND BROMOMETHANES STUDIED BY MATRIX-ISOLATION INFRARED-SPECTROSCOPY

The reactions of CH3Br, CHBr3, and CBr4 with atomic oxygen in argon ma trices were studied by infrared spectroscopy. Both O(D-1) and O(P-3) w as generated in situ by the UV photolysis of ozone. O(D-1) reacted wit h CH3Br to give H2CO+HBr or CO+H-2+HBr, with CBr4 to give COBr2+Br-2 o r CO+2Br(2), and with CHBr3 to give HCOBr+Br-2, COBr2+HBr or CO+HBr+Br -2. Additional experiments were carried out with CDBr3+O and CHBr3+O-1 8. The analogue reactions with O(P-3) resulted in only the carbonyl in termediates. All the carbonyl compounds decomposed upon prolonged phot olysis resulting in HBr and CO as final products in the matrix. The in itial step of the reactions is discussed, and an overall reaction path way is proposed.