Bimolecular Reaction of N2O with CO and the Recombination of O and CO as Studied in a Single-Pulse Shock Tube

Abstract

The reaction between N₂O and CO was studied in a single‐plus shock tube over the temperature range 1320°–2280°K, in mixtures of the reactants highly diluted with Ar. In the range of temperatures 1317°–1908°K the rate constant for the bimolecular reaction, $${\mathrm{N}}_2\mathrm{O}+\mathrm{CO}\to {\displaystyle {lim}^1}{\mathrm{N}}_2+{\mathrm{CO}}_2,$$ was found to be $k_1{\text{\hspace{0.17em}=\hspace{0.17em}1.1\hspace{0.17em}×\hspace{0.17em}10}}^{11}\exp \text{(−\hspace{0.17em}23 000\hspace{0.17em}/\hspace{0.17em}}\mathrm{RT}){\mathrm{cm}}^3{\mathrm{mole}}^{\text{−1}}·{\sec }^{\text{−1}}$ . From the rates of formation of CO₂ above 1642°K, a constant for the nonradiative third‐order recombination of O and CO was obtained (for the temperature range 1500°–3000°K), $$\mathrm{O}+\mathrm{CO}\text{+Ar5→}{\displaystyle {lim}^5}{\mathrm{CO}}_2+\mathrm{Ar},$$ $k_5{\text{\hspace{0.17em}=\hspace{0.17em}2.8\hspace{0.17em}×\hspace{0.17em}10}}^{12}\exp \text{(+\hspace{0.17em}23 800\hspace{0.17em}/\hspace{0.17em}RT)}{\mathrm{cm}}^6{\mathrm{mole}}^{\text{−2}}·{\sec }^{\text{−1}}$ . The large negative activation energy so deduced is shown to be in full agreement with the low value for the activation energy previously observed for CO₂ decomposition. An energy diagram was constructed on the basis of a recent CO flame study and results on the limiting high‐pressure CO₂ decomposition. The mechanisms for the radiative and the three‐body recombination, and the dissociation of CO₂, are discussed in terms of this energy diagram.