Thermal Decomposition of Cyanogen Measured in C2N2/O2 and C2N2/H2 Reaction Systems by Atomic Resonance Absorption

Abstract

AbstractThe thermal decomposition of cyanogen has been measured behind reflected shock waves in the temperature range 1900–2650 K at pressures of about 1.8–2.0 bar using Atomic Resonance Absorption Spectroscopy (ARAS). C2N2/O2 and C2N2/H2 mixtures highly diluted in argon were shock heated and O and H atom concentrations were monitored in the post shock reaction zone. Because of the fast secondary reactions of the dissociation product CN, the measured concentrations of O or H were strongly dependent on the rate of dissociation of cyanogen. The experimentally determined rate coefficient data for the dissociation of cyanogen are closely fit by the Arrhenius expression: k = · 2.97 10−7 exp(−53665 K/T)cm3/s. The present rate coefficient data is compared with the results of previous investigators and also with the estimates obtained from the weak collision unimolecular reaction rate theory.