Flame photometric studies of reactions induced by nitric oxide in hydrogen-oxygen—nitrogen flames

Abstract

Abstract It has been found that nitric oxide is an effective homogeneous catalyst for the recombination of atomic hydrogen and hydroxyl radicals in fuel-rich flames of hydrogen, oxygen and nitrogen at atmospheric pressure. The results are consistent with the mechanism H + NO + M ⇌ HNO +M, HNO + H → H2 + NO (k4), HNO + HO → H2O + NO or H2 + NO2 (k5), and the following values for k4 and k5 are obtained: k4 = (1·0 ± 0·5) x 10-11cm3 molecule-1 s-1, k5 = (1·5 ±0·5) x 10-10 cm3 molecule-1 s-1, with no significant temperature effect from 1600 to 2000 °K. Alternative mechanisms are discussed.