PRIMARY PRODUCTS OF THE ELEMENTARY REACTIONS OF CH2CO WITH F, CL, ANDOH IN THE GAS-PHASE

The absolute yields of the primary products of the reactions of CH2OH with F and Cl atoms and OH radicals were measured in the gas phase at room temperature using a discharge flow apparatus connected to a Far I nfrared Laser Magnetic Resonance (FIR-LMR) spectrometer. Quantitative determinations of the reaction pathways were carried out by employing reference reactions with known product yields. The measurements yielde d the branching ratios for the following channels CH2CO+F --> HCCO+HF k1c/k1 = 0.05 +/- 0.03 (1 c) --> CH2F+CO k1d/k1 = 0.87 +/- 0.06 (1 d) CH2CO+Cl --> HCCO+HCl k2c/k2 less-than-or-equal-to 0.01 (2 c) --> CH2C l+CO k2d/k2 = 0.97 +/- 0.07 (2 d) CH2CO+OH --> HCCO+H2O k3b/k3 less-th an-or-equal-to 0.01 (3 b) --> HCO+H2CO k3c/k3 less-than-or-equal-to 0. 02 (3 c) --> CH2OH+CO k3e/k3 = 0.60 +/- 0.10. (3 e) Thus, the main rea ction channels were found to be addition of the F, Cl, or OH, respecti vely, to the CH2 moiety followed by elimination of CO.