Shock tube determination of the overall rate of NH2+NO -> products in the Thermal De-NOx temperature window

The rate coefficient of the reaction NH2 + NO products (R I) was determined in shock tube experiments using frequency-modulation absorption spectrosco py for detection of NH2 Because of the sensitivity of the diagnostic system , very low reactant concentrations could be employed in order to reduce the influence of secondary reactions on the NH2 profiles. Benzylamine, C6H5CH2 NH2, was used as a thermal source of the NH2 radicals in the experiments. T o determine the reaction rate, a perturbation strategy was employed that is based on changes in the NH2 profiles when NO is added to the C6H5CH2NH2/Ar mixtures. The measured NH2 profiles were interpreted by detailed kinetic m odeling to obtain the overall reaction rate of R I in the temperature range 1262-1726 K. The lower temperature limit of the present study is in the mi ddle of the Thermal De-NOx temperature window. The present rate measurement s are consistent with both our previous determination of the rate at higher temperatures and lower temperature data. A rate expression obtained by com bining our higher temperature data and lower temperature data is k(1) = 6.83 x 10(15) T (-1.203) e(106/T (K)) cm(3) Mol(-1) s(-1) for the temperature range 200-2500 K. The estimated uncertainty of the rate coefficient is +/- 20%. (C) 2001 John Wiley & Sons, Inc.