Kinetic, mechanistic and temperature dependence study of Cl reactions.

BRAVO, I.; ARANDA, A.; DIAZ DE MERA,Y.; MORENO, E.; MARIA EUGENIA TUCCERI; RODRIGUEZ, D.

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

Año: 2009 p. 384 - 390

1463-9076

Reactions of Cl atoms with CH3OC(O)H (1) and CH3CH2OC(O)H (2) have been studied using the Discharge Flow-Mass Spectrometric (DF-MS) method. The study has been carried out at 1 Torr total pressure under pseudo-first-order conditions in the temperature range 253 K to 333 K to approach the tropospheric temperature profile. The measured room temperature rate coefficients are k(1) = (1.01 ± 0.15) x 10-12 cm3 molecule-1 s-1 and k(2) = (8.78 ± 1.22)x10-12 cm3 molecule-1 s-1 (errors are 2s) and the fitted Arrhenius expressions, k(1) =(1.7 ± 1.4) x10-11 exp -(810 ± 250)/T cm3 molecule-1 s-1 and k(2) = (5.5 ± 4.8) x10-11exp -(556 ± 268)/T cm3 molecule-1 s-1 (errors are 2s). The reactions proceed through the abstraction of an H atom to form HCl and the corresponding radical. At 298 K and 1 Torr, yields on HCl of 0.95 ± 0.09 (error is 2s) for reaction (1) and 0.96 ± 0.11 (error is 2s) for reaction (2) have been measured. The tropospheric lifetimes are calculated and discussed.