Gas-phase kinetics of the reactions of the CH2F radicals with the radicals CHF2, CH3, and C2H5

The mechanisms and the rates of the reactions of the fluorinated hydrocarbon radical CH2F with the fluorinated and pure hydrocarbon radicals CHF2 CH2, and C2H5, respectively, have been studied at low pressure (around 2 mbar) and room temperature using the discharge-flow reactor technique. Mass spectrometry either with electron impact or laser induced multiphoton ionization was applied for the detection of labile and stable species. The cross combination of the radicals is mainly followed by HF elimination from the chemically activated adduct. The overall rate coefficients at 298 K for CH2F + CHF2 --> C2H2F2 + HF (1) CH2F + CH3 --> C2H4 + HF (2) CH2F + C2H5 --> C3H6 + HF (3) were derived from the analysis of the radical-time profiles by fit procedures; the following values were obtained: k(1) = (3.0 + 1.5/ - 0.7) x 10(12) cm(3) mol(-1) s(-1) k(2) = (4.0 +/- 1.5) x 10(12) cm(3) mol(-1) s(-1). k(3) = (9.0 +/- 3) x 10(12) cm(3) mol(-1) s(-1). The results are discussed in terms of chemical activation mechanisms.