Kinetic, mechanistic and temperature dependence study of Cl reactions with CH3OC(O)H and CH3CH2OC(O)H. Atmospheric implications

• Published in: Physical chemistry chemical physics : PCCP Vol. 11; no. 2; p. 384
• Main Authors: Bravo, Iván, Aranda, Alfonso, Díaz-de-Mera, Yolanda, Moreno, Elena, Tucceri, Maria E, Rodríguez, Diana
• Format: Journal Article
• Language: English
• Published: England 14-01-2009
• Subjects: Acetic Acid - chemistry; Atmosphere - chemistry; Chlorine - chemistry; Kinetics; Propionates - chemistry; Temperature
• ISSN: 1463-9076
• DOI: 10.1039/b810285f

Reactions of Cl atoms with CH(3)OC(O)H (1) and CH(3)CH(2)OC(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) cm(3) molecule(-1) s(-1) and k(2)=(8.78+/-1.22) x 10(-12) cm(3) molecule(-1) s(-1) (errors are 2sigma) and the fitted Arrhenius expressions, k(1)=(1.7+/-1.4) x 10(-11) exp -(810+/-250)/T cm(3) molecule(-1) s(-1) and k(2)=(5.5+/-4.8) x 10(-11) exp -(556+/-268)/T cm(3) molecule(-1) s(-1) (errors are 2sigma). 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 2sigma) for reaction (1) and 0.96+/-0.11 (error is 2sigma) for reaction (2) have been measured. The tropospheric lifetimes are calculated and discussed.