Flow tube calibration and infrared product studies using hydrogen and hydroperoxyl gas-phase radical reactions with nitrogen oxides

Gas-phase reactions of nitrogen oxides with hydrogen and hydroperoxyl radicals were investigated in the laboratory by a newly built flow tube instrument. A multipass White cell was attached and an infrared spectrophotometer measured chemical absorbance and concentration at pressures from 2 to 62 Torr. Gas flows were optimized to maximize the production of hydrogen and hydroperoxyl radicals and to control the concentration and velocity of gaseous species. The pathlength of the White cell was measured by use of multiple IR-active gases and its value was constrained to 500--800 cm.;A product study concluded that the reaction of HO2 + NO at 62 Torr and 295 K produced 71 +/- 5% NO2, 17 +/- 3% HONO 2, and 63 +/- 42% HONO after a reaction time of 1.8 s. Another product study of the reaction of H + NO2 at 51 Torr and 295 K qualitatively showed the production of products.