Kinetic study of the Belousov-Zhabotinsky reaction with phenylmalonic acid

In a stirred batch experiment, ferroin (Fe(phen)₃²⁺) behaves differently from Ce(III) or Mn(II) in catalyzing the bromate-driven oscillating reaction with phenylmalonic acid (PhMA), bromophenylmalonic acid (BrPhMA), or dibromomalonic acid (Br₂MA). The kinetics of reactions of PhMA or BrPhMA with Ce(IV), Mn(III), or ferriin (Fe(phen)₃³⁺) ion were studied under anaerobic or aerobic conditions. The order of reactivity under anaerobic or aerobic conditions is ferriin-PhMA reaction > Mn(III)-PhMA reaction > Ce(IV)-PhMA reaction > ferriin-BrPhMA reaction ≫ Ce(IV)- or Mn(III)-BrPhMA reaction. Additional reaction processes including the redox reactions of ferroin and ferriin ions with organic bromides and inorganic bromine species are considered to rationalize the main differences between the ferroin-catalyzed and the cerous-catalyzed bromate-driven oscillating reactions.