Kinetics and mechanism of Mn(II) catalyzed oxidation of acridine yellow by chloramine-T

The kinetics and mechanism of the uncatalyzed and Mn(II) catalyzed oxidation of acridine yellow (3,6-diamino-2,7-dimethyl acridine hydrochloride) dye by chloramine-T in acidic media has been studied using spectrophotometry. With excess concentrations of other reactants, the reaction rate follows pseudo first order kinetics with respect to acridine yellow. The uncatalyzed reaction has fractional order dependence on chloramine-T as well as on H+ concentration. The catalyzed reaction follows first order kinetics in catalyst [Mn(II)]. Variations of ionic strength has no influence on the reaction rate suggesting that neutral charged species are involved in the rate determining step. Increase in the addition of p-toluenesulfonamide results in decrease in rate constant values. The basic stoichiometric equation is as follows: AY(+) + ArSO2NHCl + H2O = P+ + ArSO2NH2 + CH3CH2OH + CH3CN +2HCl, where P+ = 7-aminoquinoline-2, 3-dicarboxylic acid. The lowest catalytic limit for Mn(II) has been found to be 1.0 x 10(-8) mol dm(-3). On the basis of various kinetic investigations and product analysis mechanisms have been proposed.