The gas-phase reaction of CF3 radicals with HCN in the temperature range 333–523 K

Abstract

The reaction of CF₃ radicals produced by photolysis of CF₃I with HCN has been investigated in the temperature range 333–523 K. The radicals react with HCN by addition followed by a sequence of reactions of which the most important are: CF₃+ HCN ⇆ CF₃HCN (1,–1), CF₃+ CF₃HCN → HCF₃CNCF₃(2), CF₃+ CF₃HCN → CF₃H + CF₃CN(3), I + CF₃HCN → HI + CF₃CN (4) 2 CF₃ [graphic omitted] C₂F₆. Arrhenius parameters for the addition reaction relative to radical recombination were estimated from experiments at conversions [graphic omitted] 3% in the temperature range 333–453 K. The best fit to our experimental results gave log[(A₁/A^1/2_c) cm^3/2 mol^–1/2 s^–1/2]= 4.97 and E₁–½E_c= 30.9 kJ mol^–1, with systematic estimated errors of up to 0.3 and 2.4 kJ mol^–1, respectively. These parameters are compared with those obtained for other addition reactions of these radicals to substrates with a triple bond.