A Comparative Rate Method for the Study of Unimolecular Falloff Behavior

Article abstract of DOI:10.1021/j150653a034

A comparative method was applied to a high-temperature fast-flow reactor to determine relative kinetic parameters for the two-channel decomposition of cyclobutanone in the falloff region.The applicability of this method to such nonthermally equilibrated systems was assessed and found to be generally useful over a wide range of conditions.The measurements could, therefore, be used as a quantitative diagnostic tool for sensing unimolecular falloff behavior in a number of heat bath gases.A simple stepladder collisional activation-deactivation model was used to determine the energy transferred per collision.The values obtained for the heat bath gases He, Ar, SiF4, and SF6 were 3.0, 2.0, 3.5, and 4.0 kcal/mol, respectively.These are small multiples of RT and very small fractions of the activation energy, indicating that weak collisions must be a dominant feature of reaction types represented by the decomposition of cyclobutanone.