Atmospheric sink of methyl chlorodifluoroacetate and ethyl chlorodifluoroacetate: temperature dependent rate coefficients, product distribution of their reactions with Cl atoms and CF2ClC(O)OH formation

MARÍA BELÉN BLANCO; IAN BARNES; PETER WIESEN; MARIANO TERUEL

Royal Society Chemistry Advances

RSC

Lugar: Cambridge; Año: 2016 vol. 6 p. 51834 - 51834

ate coefficients in function of temperature have been measured for the first time for the gas-phase reactions of chlorine atoms with methyl chlorodifluoracetate (k1) and ethyl chlorodifluoroacetate (k2) using the relative rate technique. The experiments were carried out in a 1080 L photoreactor over the temperature range 287?313 K at a total pressure of 1000 ± 10 mbar of synthetic air using in situ FTIR spectroscopy to monitor reactants and products. The following Arrhenius expressions were obtained: k(MCDFA+Cl) = (9.6 ± 5.1) x 10-12 exp [-(1363 ± 79)/T] and k(ECDFA+Cl) = (64.4 ± 29.7) x 10-12 exp [-(1110 ± 68)/T]. The kinetic results are compared with previous experimental and theoretical studies.In addition, a product study of the reactions of Cl with methyl chlorodifluoracetate and ethyl chlorodifluoroacetate is reported. The results indicate that in the absence of NOx the main fate of the alkoxy radicals formed after H-atom abstraction by Cl from the ?CH3 group in methyl chlorodif