Relationship between isotopic scrambling and mechanism in labeled ion molecule reactions: The reaction of CH3+ with CH4

The isotopically mixed products of the reaction of CH3+ with CD4 and CD3+ with CH4 are analyzed in terms of the reaction mechanism. It is concluded that the products are not randomly distributed, and that three separate and distinguishable reaction channels may be operative with H2 elimination from the initial ionic carbon the most likely channel. No intermediate is invoked to explain the observed results, and it is shown that significant H–D scrambling during the reaction is not necessary to account for the isotopically mixed products observed.