The rates of bromination of 2,6-diethylaniline, 2.4-dimethylaniline, 2.6-dichloroaniline, and 2.4-dichloroaniline have been measured over a wide range of acidities in aqueous perchloric acid, and that of 4-bromo-N-dimethylaniline in aqueous sulphuric acid. The effect of bromide ion concentration at constant acidity was also studied for the four primary amines. The inverse acidity dependence follows either Ho or Hi" according to whether the amine is primary or tertiary, and for 4-bromo-N-dimethylaniline there is an additional inverse dependence upon the water activity. The effect of bromide ion concentration shows that at low bromide-ion concentrations the rate-determining step for the primary amines is the reaction between molecular bromine and undissociated amine. At higher bromide-ion concentrations the decomposition of the Wheland intermediate becomes partially ratedetermining.
Kinetics of the Bromination of some Aromatic Amines in Aqueous Perchloric Acid
DE MARIA, Paolo
1969-01-01
Abstract
The rates of bromination of 2,6-diethylaniline, 2.4-dimethylaniline, 2.6-dichloroaniline, and 2.4-dichloroaniline have been measured over a wide range of acidities in aqueous perchloric acid, and that of 4-bromo-N-dimethylaniline in aqueous sulphuric acid. The effect of bromide ion concentration at constant acidity was also studied for the four primary amines. The inverse acidity dependence follows either Ho or Hi" according to whether the amine is primary or tertiary, and for 4-bromo-N-dimethylaniline there is an additional inverse dependence upon the water activity. The effect of bromide ion concentration shows that at low bromide-ion concentrations the rate-determining step for the primary amines is the reaction between molecular bromine and undissociated amine. At higher bromide-ion concentrations the decomposition of the Wheland intermediate becomes partially ratedetermining.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
