KINETICS AND MECHANISM OF PALLADIUM(II) CATALYZED OXIDATION OF AMINESAND AMINOALCOHOLS BY N-BROMOSUCCINIMIDE IN PERCHLORIC-ACID

The kinetics of oxidation of amines (EtNH2, Et2NH, Et3N) and aminoalco hols [H2NCH2CH2OH, H2N(CH2)3OH, (CH2CH2OH)2NH, (CH2CH2OH)3N] by N-brom osuccinimide (NBS) have been studied in aqueous HClO4 with PdCl2 as ca talyst, and in the presence of Hg(OAC)2 to ensure oxidation by pure NB S. The order of reaction with respect to NBS was unity, however, an in crease in [NBS]0 resulted in a decrease in the rate constant. The rate was directly proportional to [Pd(II)] for the aminoalcohols while for EtNH2 the rate was proportional to {k + k''[Pd(II)]} (where k and k'' are rate constants for the uncatalysed and catalysed paths, respectiv ely). Retarding effects for HClO4, succinimide, Cl- and AcOH on the ra te of oxidation were observed. The kinetic data support the formation of [Pd(II)-A] and [Pd(II)-(A)2] complexes (where A represents amine or aminoalcohol). A mechanism, consistent with the observed kinetic data , is proposed.