Kinetics of the reaction of nitric oxide with hydrogen

The reaction of nitric oxide with hydrogen has been studied in the temperature range 2400°−4500°K using a shock-tube technique. Mixtures of NO and H2 diluted in argon or krypton were heated by incident shock waves, and the infrared emission from the fundamental vibration-rotation band of NO at 5.3 microns was used to monitor the time-varying NO concentration. The decomposition of nitric oxide behind the shock was found to be modeled well by a fifteen-reaction system. A principal result of the study was the determination of the rate constant for the reaction H + N O → 1 N + OH which may be the rate-limiting step for NO removal in some combustion systems. Experimental values of k1 were obtained for each test through comparisons of measured and numerically predicted NO profiles. The data are fit closely by the expression k1=1.34×1014 exp(−49 200/RT) cm3/mole-sec. These data appear to be the first available for this rate constant.