Absolute rate coefficients for the reaction of H-atoms with N 2O and some reactions of CN radicals

Abstract

The reaction of H atoms with N 2 O was studied in an isothermal flow reactor (718°K≤ T ≤1111°K) with quantitative ESR detection of atoms and radicals. The measured stoichiometry of [H] (reacted)/[OH] (formed) substantiated the reaction H+N 2 O→N 2 +OH (1) The temperature dependence of the rate coefficient of reaction (1) is described by k 1 =(2.2±0.7)·10 14 exp(− E A /RT ) cm 3 /mol sec E A =(72.4±2.9) kJ/mol Reactions of CN radicals were investigated directly in an isothermal flow reactor (275°K≤ T ≤398°K). The decay of CN radicals, produced by C 2 N 2 + hv (λ≥165 nm)→2CN in the presence of a high excess of reactants was followed by kinetic absorption spectroscopy. The rate coefficients of the reactions CN+H 2 →HCN+H CN+O 2 →NCO+O were found to be k 12 =(6±2)·10 13 exp(− E A /RT ) cm 3 /mol sec E A =(22.2±2.5) kJ/mol and k 16 =(3.2±1)·10 13 exp(− E A /RT ) cm 3 /mol sec E A =(4.2±1.4) kJ/mol For the reaction CN+O→CO+N no temperature dependence of k 17 (298°K)=(1.2±0.4)·10 13 cm 3 /mol sec between 275° and 387°K could be observed.