Shock tube studies of the N2O/Ar and N2O/H2/Ar systems

N2O decay has been monitored via infrared emission for a series of mixtures containing N2O/Ar and N2O/H2/Ar. These mixtures were studied behind reflected shock waves in the temperature interval of 1950–3075°K with total concentrations ranging from 1.2 to 2.5 × 1018 molec/cm3. In all cases the N2O decayed exponentially, and a rate constant kobs was obtained. Runs without added H2 could be described by the following Arrhenius parameters: log A = −9.72 ± 0.08 (in units of cm3/molec · sec) and EA = 203.5 ± 3.6 kJ/mole. Addition of 0.01% and 0.1% H2 was observed to increase the decay rate; the largest increase occurred between 2250 and 2500°K with 0.1% H2, where kobs doubled. Mixtures with no added H2 were analyzed by numerical integration of the following reactions: equation image Quantitative agreement between calculations and observations were obtained with both high and low choices for k2 and k3. The additional reactions equation image were included in the analysis of the mixtures containing H2. Here agreement was obtained only when low values were assigned to k2 and k3. The combinations of k1 ← k3 which agreed with all the data were k1 = 3.25 × 10−10 exp (−215 kJ/RT) and k2 = k3 = 1.91 × 10−11 exp (‐105 kJ/RT).