Reaction probabilities and threshold energy in the reaction of isotopically pure hydrogen atoms and ethane

Abstract

The reaction of photochemically generated hydrogen atoms of selected energies with ethane has been investigated. It has been possible for the first time to measure reaction probabilities for H + C₂H₆→ H₂+ C₂H₅, analogous studies of all previous abstraction reactions with akanes having been for isotopically mixed systems. This was achieved by monitoring the ethyl product through scavenging and gas–liquid chromatographic analysis, as well as mass-spectrometric determination of H₂. The phenomenological laboratory threshold energy was found to be 51 ± 2 kJ mol^–1, and this value and the measured integral reaction probabilities were compared with those for D + C₂H₆ and H + C₂D₆. The onset of a substitution reaction may have been detected at high atom energies.