Aromatic substitution in the gas phase. Part I. Reaction of the helium tritiide molecular ion with halogenobenzenes

Abstract

The results of a study of the reactions of the powerful Brønsted acid, the HeT⁺ ion from the β-decay of molecular tritium, with gaseous fluorobenzene, chlorobenzene, and bromobenzene are reported. In all the systems investigated, the tritiated halogenobenzene is the major product, and is accompanied, except in the case of fluorobenzene, by smaller amounts of tritiated benzene. The nature and the yields of the products, and their intramolecular tritium distribution, suggest, that reaction is analogous to electrophilic substitutions occurring in solution. Mechanisms are discussed.