Cyanogen pyrolysis and the CN + NO reaction behind incident shock waves

The reaction chemistry of C 2 N 2 Ar and C 2 N 2 NOAr mixtures has been investigated behind incident shock waves. Progress of the reaction was monitored by observing the cyano radical (CN) in absorption at 388.3 nm. A quantitative spectroscopic model was used to determine concentration histories of CN. From initial slopes of CN concentration during cyanogen pyrolysis, the rate constant for C 2 N 2 + M → 2CN + M (1) was determined to be k 1 = (4.11 ± 1.8) × 10 16 exp(−47,070 ± 1400/ T ) cm 3 /mol · s. A reaction sequence for the C 2 N 2 NO system was developed, and CN profiles were computed. By comparison with experimental CN profiles the rate constant for the reaction CN + NO → NCO + N (3) was determined to be k 3 = 10 (14.0 ± 0.3) exp(−21,190 ± 1500/ T ) cm 3 /mol · s. In addition, the rate of the four‐centered reaction CN + NO → N 2 + CO (2) was estimated to be approximately three orders of magnitude below collision frequency.