Threshold energy in the abstraction reaction between hydrogen atoms and propane

Abstract

The reactions of photochemically generated deuterium atoms of selected initial translational energy with propane have been investigated. At each initial energy the relative probability of the atoms undergoing reaction or energy loss on collision with propane was investigated, and the phenomenological threshold energy was measured as 32±4 kJ mol–1 for the abstraction from the secondary C–H bonds. The ratio of relative yields per bond, secondary : primary was ∼3 at the higher energies studied. The correlation of threshold energies with bond dissociation energies, heats of reaction and activation energies is discussed for abstraction reactions with several hydrocarbons.