Abstract.
Comparative study of the kinetics of oxidation of
phenylpropanolamine hydrochloride (PPA) by chloramine-B (CAB)
and chloramine-T(CAT) catalyzed by Pd (II) chloride in
perchloric acid médium has been studied at 308 K. Addition of
mercuric acetate ions and the reduction product of oxidants,
benzenesulfonamide (BSA),methyl benzene sulphonamide have no
significant effect on the rate of reaction. Reaction follows
first order kinetics in case of oxidants and
Pd(II)chloride.Increase in [H+] showed positive
effect in case of chloramines-B oxidation while showed
negligible effect in case of chloramines-T oxidation.Addition of
chloride ions showed negligible effect in case of Chloramine-B
while positive effect in case of chloramine-T. Phenylpropalamine
(substrate) followed zero orde kinetics in case of both
oxidants. The reaction was studied at different temperatures and
the activation parameters have been computed from the Arrhenius
plot. The stoichiometery of the reaction was found to be 1:1 and
the main oxidation producís of PPA were found to be benzaldehyde
and acetaldehyde.Formation and decomposition constant of
Oxidant-PPA complexes in the reaction scheme have been
evaluated. The conjúgate acid C6H5S02NHCl,and
CH3C6H4S02NHCl has
been assumed to be the reactive species of chloramine-B and
chloramines-T respectively.The observed results have been
explained by plausible mechanisms and relative rate law has been
deduced.
Keywords: Phenylpropanolamine hydrochloride,
chloramine-B,chloramine-T, oxidation Kinetics, Pd(II)-catalysis,
perchloric acid medium.