Mechanism of the photochemical chain reaction of substitution of the sulpho group for halogens in 4-halo-1-naphthylamines in an aqueous sodium sulphite solution

V.L. Ivanov, S.Yu. Lyashkevich

High Energy Chemistry, v.33 (4), p. 232-236 (1999), translated from Russ. Khimia Vysokikh Energii, v.33 (4), p. 274-278 (1999)

ABSTRACT. A substitution reaction, in which a halogen is replaced by the sulpho group, proceeds upon irradiation of halogenated naphthylamines (4-chloro-1-naphthylamine and 4- bromo-1-naphthylamine) in an aqueous sodium sulphite solution. The substitution reaction is a chain reaction, because the quantum yield of the reaction is higher than unity at a low intensity of absorbed light. It was found that the photosubstitution reaction involves the triplet state of halonaphthylamine and that sulphite radical anions are responsible for the chain propagation. The reaction of the photosubstitution of a halogen by sulpho group in halonaphthylamines can be sensitized by dyes.

Laboratory of Photochemistry