Kinetic study of the Ce(III)-, Mn(II)- or Fe(phen)(3)(2+)- catalyzed Belousov-Zhabotinsky reaction with 2-ketoglutaric acid

The Belousov-Zhabotinsky (BZ) reaction of bromate ion with 2-ketoglutaric a cid (KGA) in aqueous sulfuric acid catalyzed by Ce(III), Mn(II), or Fe(phen )(3)(2+) ion exhibits sustained barely damped oscillations under aerobic co nditions. In general, the reaction oscillates without an induction period. Fe(phen)(3)(2+) ion behaves differently from Ce(III) and Mn(II) ions in cat alyzing this oscillating system. The gem-diol form of KGA exhibits differen t behavior from that of the keto form of KGA in the BZ reaction. The kineti cs and mechanism of the reaction of KGA with Ce(IV), Mn(III), or Fe(phen)(3 )(3+) ion was investigated. The order of relative reactivities of metal ion s toward reaction with KGA is Mn(III) > Ce(IV) much greater than Fe(phen)(3 )(3+). Experimental results are rationalized. (C) 2001 John Wiley & Sons, I nc.