Kinetics of CN radical reactions with formaldehyde and 1,3,5‐trioxane

Absolute rate constants were measured for the reaction CN + CH₂O over the temperature range 297–673 K and CN + 1,3,5‐trioxane over the range of 297–600 K by the laser photolysis/laser induced fluorescence technique. The rate constants for these reactions can be effectively represented, in units of cm³/s, by: k(CH₂O) = 2.82 × 10⁻¹⁹ T^2.72 exp(718/T), and k(1,3,5‐trioxane) = 1.39 × 10⁻²³ T^4.26 exp(1333/T), respectively. Transition state theory calculations were able to fit the temperature dependence of the CN + CH₂O rates relatively well. We attempted to correlate the CN reaction rate with CH₂O and other molecules which occur through simple abstraction with the corresponding OH reaction rates, yielding only a qualitative linear correlation for a majority of the processes. The reactions which deviated significantly from linearity include those which contain strong dipoles, highlighting the significant role long‐range attractive forces play in CN and OH reactions. Using a simple electrostatic potential, cross‐sections were determined for reactions with CN. No linear correlation was found between the calculated and experimental cross sections for the majority of the reactions studied. © 1993 John Wiley & Sons, Inc.