Formation of NO from N2/O2 Mixtures in a Flow Reactor: Toward an Accurate Prediction of Thermal NO

ABSTRACT We have conducted flow reactor experiments for NO formation from N 2 /O 2 mixtures at high temperatures and atmospheric pressure, controlling accurately temperature and reaction time. Under these conditions, atomic oxygen equilibrates rapidly with O 2 . The experimental results were interpreted by a detailed chemical model to determine the rate constant for the reaction N 2 + O ⇌ NO + N (R1). We obtain k 1 = 1.4 × 10 14 exp(−38,300/ T ) cm 3 mol −1 s −1 at 1700–1800 K, with an error limit of ±30%. This value is 25% below the recommendation of Baulch et al. for k 1 , while it corresponds to a value k 1b of the reverse reaction 25% above the Baulch et al. evaluation. Combination of our results with literature values leads to a recommended rate constant for k 1b of 9.4 × 10 12 T 0.14 cm 3 mol −1 s −1 over 250–3000 K. This value, which reconciles the differences between the forward and reverse rate constant, is recommended for use in kinetic modeling.