CN radical reactions with hydrogen cyanide and cyanogen: Comparison of theory and experiment

Absolute rate constants were obtained for CN radical reactions with HCN and C₂N₂ employing the method of laser photolysis/laser induced fluorescence. The rate constants were found to be temperature dependent in the range 300-740 K and pressure independent in the range 100-600 Torr. The rates for CN + HCN may be described well, in units of cm³/s, by k(HCN) = 2.50×10^-17T^1.71 exp( - 770/T), which includes the shock tube results of Szekely et al. at 3000 K [Int. J. Chem. Kinetics 15, 1237 (1983)]. The measured rates for CN + C₂N ₂ may be described well by k(C₂N₂) = 2.19×10^-21T^2.70 exp( - 325/T). Rice-Ramsperger- Kassel-Marcus (RRKM) theory calculations employing transition state parameters predicted by the BAC-MP4 method were able to account for the effects of temperature and pressure on both reactions.