OXIDATION KINETICS AND MECHANISTIC INVESTIGATION OF QUININE SULPHATE BY CHLORAMINE-B IN ACIDIC CHLORIDE SOLUTIONAbstract
The kinetics of oxidation of quinine sulphate [8α, 9R-61– methoxycinchonan- 9 – ol sulphate], (QS) by Chloramine-B (Sodium N-Chlorobenzene Sulphonamide, CAB) has been studied in aqueous hydrochloric acid medium at 303 K. The reaction rate shows a first order with respect to [CAB], fractional order with respect to [HCl] and [QS]. Activation parameters were evaluated from the kinetic data at different temperatures. Negative entropy of activation indicated the involvement of a rigid complex in the activated state. The dielectric constant of the medium has a small effect on the rate. Ionic strength and the reduction product benzene sulphonamide [BSA] do not affect the reaction rate. The solvent isotope effect is studied. The reaction products are identified and characterized by spectral (IR and NMR) data. The proposed reaction mechanism and the derived rate equation are consistent with the observed kinetic data.
N. Nanda * and P. Kumar
Department of Chemistry, B. M. S. College for Women, Basavanagudi, Bangalore, Karnataka, India.
11 March 2014
29 April 2014
04 July 2014
01 September 2014