Kinetic and Mechanistic Investigation for the Gas-Phase Tropospheric Photo-oxidation Reactions of 2,2,2-Trifluoroethyl Acrylate with OH Radicals and CI Atoms

The photo -oxidation of 2,2,2-trifluoroethyl acrylate (TFEA) (CF12CHC(0)0CH2CF3) initiated by OH radicals and Cl atoms was investigated in tropospheric conditions using both e)q)erimental and computational methods. The kinetic measurements were carried out in the temperature range of 268-363 K using the relative rate method. The ate coefficients for the reaction of OH radicals with TFEA were measured relative to diethyl ether, ethylene, and acetaldehyde. The rate coefficients for the reaction of Cl atoms with TFEA were measured relative to propylene and ethylene. The rate coefficients for the reaction of TFEA with OH radicals and Cl atoms at 298 K were experimentally measured to be keKT - 298 K (1.41 0-31) X 10-11 cm3 molectlle-1 s-1 and keKxPz - 298 K (2.37 0.50) X 10-1 cm3 molecule -1 s-1, respectively. The deduced temperature -dependent Arrhenius expressions for the reactions of OH radicals and CI atoms with TFEA are k (268 - 363 = (9.82 1.37) x 10-12 exp. [(812 152)/T] cm3 molecule -1 s-1 and icff - (268 363 K) = (1.25 0.17) X 10-11 eV. [(862 85)/T] cni3 molecule -1 s-1, respectively. To complement our experiniental results, computational calculations were performed at CCSD(T)/cc-pAIDZ//114062X/6-31+G(d,p) and CCSD(T)/cc-pVEllZ// MP2/6-311+G(d,p) levels of theory, respectively, in combination with canonical variational transition-state theory (CVT) with small curvature tunneling (SCT) over the temperature range of 200-400 K. Furthermore, the degradation mechanisms initiated by OH radicals and Cl atoms were proposed for the titled reactions based on the qualitative analysis of the products in gas chromatography mass spectroinetry (GC MS) and gas ciiromatograiiiiy_infrared spectroscopy (GC-IR). Atmospheric implications, therinochemistry, and branching ratios for the titled reactions are discussed in detail in the paper