ABSOLUTE AND RELATIVE RATE CONSTANTS FOR THE REACTIONS CH3C(O)O-2-2+NO2 AND THERMAL-STABILITY OF CH3C(O)O2NO2(NO AND CH3C(O)O)

A pulse-radiolysis system was used to measure absolute rate constants for the reactions of CH3C(O)O-2 radicals with NO and NO2 at 295 K and 1000 mbar total pressure of SF6. When the rate of formation and decay of NO2 using its absorption at 400.5 and 452 nm were monitored, the ra te constants k(CH3C(O)O-2 + NO) = (2.0 +/- 0.3) x 10(-11) and k(CH3C(O )O-2 + NO2) = (1.0 +/- 0.2) x 10(-11) cm(3) molecule(-1) s(-1) were de termined; Long path-length Fourier transform infrared spectrometers we re used to study the rate-constant ratio K(CH3C(O)O-2 + NO)/k(CH3C(O)O -2 + NO2) in 6-700 Torr total pressure of N-2 diluent at 243-295 K. At 295 K in 700 Ton of N-2 diluent k(CH3C(O)O-2 + NO)/k(CH3C(O)O-2 + NO2 ) = 2.07 +/- 0.21. The results are:discussed in the context of the-atm ospheric chemistry of acetylperoxy radicals.