Abstract
Rate coefficients as a function of temperature and product distribution studies have been performed 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.
Highlights
Oxygenated Volatile Organic Compounds (OVOCs) such as hydro uoroethers (HFEs) and hydrochloro uoroethers (HCFEs) have an oxygen linkage which makes the hydrogen atoms of the ether molecule more labile and increases their reactivity toward OH radicals and Cl atoms in the lower atmosphere compared to chloro uorocarbons (CFCs) and hydrochloro uorocarbons (HCFCs)
Urban sources of Cl atoms due to industrial activities can exist, and Cl concentrations higher than the concentration levels observed in marine regions have been reported, for example, in the vicinity of ceramic industries.[11]
As part of a systematic study on the kinetics and oxidation products of the atmospheric reactions of haloesters, we report in this work, rate coefficients for the reactions of Cl atoms with methyl chlorodi uoroacetate and ethyl chlorodi uoracetate measured over the temperature range 287–313 K using a relative kinetic technique: ClCF2C(O)OCH3 + Cl / products
Summary
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†. Rate coefficients as a 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 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 chlorodifluoroacetate is reaction of the radical with O2 to form the mixed anhydride CF2ClC(O)OC(O)H. In the case of ethyl chlorodifluoroacetate the main fate of the alkoxy formed via H-atom abstraction by Cl from the –CH2– entity in the ethyl group is a-ester rearrangement to produce chlorodifluoroacetic acid and the corresponding radical. Atmospheric implications are discussed according to the rate coefficients obtained as a function of temperature and altitude, and regarding the formation of chlorofluorocarboxylic acid
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
