Electrophilic aromatic substitution. Part 19. The nitration of some reactive aromatic compounds in perchloric acid

Abstract

Rate profiles for nitration of m-xylene, p-xylene, mesitylene, 1,3-dimethoxybenzene, 3,5-dimethylanisole, and (when correction is made for protonation) 3,5-dimethoxytoluene and 1,3,5-trimethoxybenzene in aqueous perchloric acid are all closely similar, and probably reflect the rate of encounter between nitronium ion and aromatic compound in these media. As in sulphuric acid, anisole is nitrated slightly more slowly, and the yields of o- and p-nitroanisole are markedly acidity dependent. The rate profile for p-dichlorobenzene shows that at the highest acidity studied (72% perchloric acid) substantial conversion of nitric acid into nitronium ion has not been achieved.