Electron transfer reaction of theobromine (hereafter referred to as TB) and permanganate ion has been studied using spectrophotometric technique under pseudo first-order conditions at T = 24, [H+] = 3.2 × 10–1 mol dm–3and I = 1.0 mol dm–3 (Na2SO4). Stoichiometric study depicted that two moles of TB were consumed by one mole of permanganate ion. The rate of the reaction is first order in both [TB] and [MnO4-] and second order overall. It was observed that, [H+] and ionic strength respectively enhanced the rate of the reaction in the range studied. Michaelis-Mentens analysis showed no evidence of intermediate complex formation. Added anions and cations were observed to catalyze the reaction rate. The reaction conforms to the rate law as shown below: -d [MnO4-]/dt = (a+b [H+]) [TB] [MnO4-] where a = 0.041 dm3mol–1 s–1 and b= 0.028 dm3mol–1 s–1. The reaction thus occurs by an outer-sphere pathway and plausible mechanism is proposed for the reaction.
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