Kinetic and mechanistic study of the gas-phase reaction of CFCHCH (x=1, 2, 3, 4 and 6) with O under atmospheric conditions.

The relative-rate technique has been used to determine the rate coefficient for the reaction of CFCHCH (x = 1, 2, 3, 4 and 6) with ozone at (298 ± 2) K and (720 ± 5) Torr of air by FTIR (Fourier Transform Infrared Spectroscopy) and by GC-MS/SPME (Gas Chromatography-Mass Spectroscopy with Solid Phase Micro Extraction) in two different atmospheric simulation chambers. The following rate coefficients, in units of 10 cm molecule s, were obtained: (3.01 ± 0.10) for CFCHCH, (2.11 ± 0.35) for CFCHCH, (2.34 ± 0.42) for CFCHCH, (2.05 ± 0.31) for CFCHCH and (2.07 ± 0.39) for CFCHCH, where uncertainties represent ±2σ statistical error. The atmospheric lifetime of CFCHCH due to reaction with ozone was estimated from the reported rate coefficients. Additionally, the gaseous products formed in these reactions were investigated in the presence of synthetic air simulating a clean atmosphere. Perfluoroaldehydes, CFC(O)H (PFALs), formaldehyde, formic acid and CFO were identified as reaction products in the investigated reactions. The identified products made possible to propose a reaction mechanism that justifies the observed products. The atmospheric implications of these results are discussed in terms of the potential contribution of the atmospheric degradation of these species to PFAL and PFCA burden.