KINETIC-STUDY OF THE OH RADICAL CHAIN IN THE REACTION SYSTEM OH+C2H4+NO+AIR

The reaction OH + C2H4 was investigated in the presence of NO and O2 at 760 +/- 5 Torr total pressure and 298 +/- 2 K. OH radicals were generated by excimer laser photolysis of H2O2 at 248 nm and were detected by laser-induced fluorescence. OH concentration-time profiles, which were measured for different C2H4, NO and O2 concentrations, exhibit a significant reformation of OH radicals which is caused by a radical chain in the reaction system. Computer simulation of the system using a kinetic model was applied to analyze the experimental results. From these calculations, a rate coefficient of (9 +/- 4) x 10(-12) cm3 s-1 was determined for the reaction HOC2H4O2 + NO --> HOC2H4O + NO2 under atmospheric conditions.