OH-initiated degradation of methyl 2-chloroacetoacetate and ethyl 2-chloroacetoacetate: Kinetics, products and mechanisms at 298 K and atmospheric pressure.

Rate coefficients for the gas-phase reactions of OH radicals with CHC(O)CHClC(O)OCH (k) and CHC(O)CHClC(O)OCHCH (k) were measured using the relative technique with different reference compounds. The experiments were performed at (298 ± 2) K and 750 Torr of nitrogen or synthetic air by in situ FTIR spectroscopy and GC-FID chromatography. The following rate coefficients (in units of cmmolecule s) were obtained: k= (2.70 ± 0.51) × 10; k= (2.30 ± 0.71) × 10 and k= (3.37 ± 0.62) × 10; k= (3.26 ± 0.85) × 10. This work reports the first kinetic study for the reactions of OH radicals with the mentioned chloroacetoacetates. Additionally, product studies are reported in similar conditions of the kinetic experiments. Acetic acid, acetaldehyde, formyl chloride, and methyl 2-chloro-2-oxoacetate were positively identified and quantified as degradation products. According to the identified products, atmospheric chemical mechanisms were proposed. The environmental implications of these reactions were assessed by the tropospheric lifetimes calculations of the title chloroesters. Significant average ozone production of 4.16 ppm for CHC(O)CHClC(O)OCH and 5.98 ppm for CHC(O)CHClC(O)OCHCH respectively were calculated.