FTIR STUDY OF THE CL-ATOM INITIATED OXIDATION OF METHYLGLYOXAL

The kinetics and mechanism of Cl‐atom initiated reactions of CH3C(O)CHO were studied using the FTIR detection method in the photolysis (λ < 300 nm) of Cl2CH3C(O)CHO mixtures in 700 torr of N2O2 diluent at 298 ± 2 K. The observed product distribution over the O2 pressure range from 0–700 torr, combined with relative rate measurements, provided evidence that: (1) the primary step is Cl + CH3C(O)CHO → HCl + CH3C(O)CO with a rate constant of (4.8 ± 1.1) × 10−11 cm3 molecule−1 s−1; and (2) the predominant fate of the primary radical CH3C(O)CO under atmospheric conditions is unimolecular dissociation to CH3C(O) radicals and CO, rather than O2‐addition to yield the corresponding carbonylperoxy radical CH3C(O)C(O)OO. Copyright © 1990 John Wiley & Sons, Inc.