Gas-phase chemistry of atmospheric Cl atoms: a PLP-RF kinetic study with a series of ketones

The pulsed laser photolysis-resonance fluorescence technique (PLP-RF) has been used to determine the absolute rate coefficients for the gas-phase reactions of Cl atoms with a series of ketones at room temperature (298 K). The rate coefficients obtained (in units of cm3 molecule−1 s−1) are: 2-butanone (3.30±0.20)×10−11, 2,3-butadione (4.92±0.44)×10−13, 2-pentanone (4.57±0.28)×10−11, 3-pentanone (4.50±0.32)×10−11, 2-hexanone (6.54±0.58)×10−11, 3-hexanone (6.69±0.62)×10−11 and cyclohexanone (6.75±0.52)×10−11. The measured values were independent of pressure over the range 20–200 Torr. These rate coefficients were compared with previous studies carried out by different techniques, when data were available. Results and atmospheric implications are discussed and compared with the reactivity with OH radicals.