Measurement of the rate constant for H+O2+M→HO2+M (M=N2, Ar) using kinetic modeling of the high-pressure H2/O2/NOx reaction

The reaction of dilute H2/O2/N2 and H2/O2/Ar mixtures perturbed with small quantities of NO has been studied in a variable-pressure flow reactor between 800 and 900 K. At high pressures (10–14 atm), the consumption of H2 and the conversion of NO to NO2 were highly sensitive to the pressure-dependent reaction {fx1} Rate coefficient data for the low-pressure limit {fx2} were inferred by comparison of the experimental data with a reaction mechanism that uses the high-pressure limit k2,∞=4.52×1013 (T/300)0.6 with FcN2=0.5 and FcAr=0.45. The data obtained with M=Ar are consistent with previous shock-tube data at comparable temperatures and are in good agreement with recent recommendations for k2,0Ar. However, the data obtained for M=N2 are 40% lower than recent recommendations and are combined with previously published data to yield {fx3} over the temperature range 300–1600 K. The rate coefficient data obtained in this study are insensitive to the competing reaction {fx4} and, when used with the k1 recommendation from Pirraglia et al. [27], are in good agreement with H2/O2 explosion limit data in the intermediate temperature range of 700\2-900K.