New Observations on the Belousov-Zhabotinskii Reaction. The Oscillating Reaction of Organic Gallic Acid and Potassium Bromate Catalyzed by 1,10-o-Phenanthroline-Iron(II) Complex

The oscillating reaction involving organic gallic acid (GA), potassium bromate, and a metal ion complex has been reinvestigated. In contrast to other previous reports, this oscillating reaction is catalyzed by the [Fe(phen)_n]²⁺ ion (phen = 1,10-o-phenanthroline, n=1, 2, 3) rather than by the cerium ion. The characteristics of the oscillations depend on the temperature and on the concentrations of the potassium bromate, gallic acid, [Fe(phen)_n]²⁺, and sulfuric acid. A cyclic voltammetric study indicates that the redox potential and the reversibility of the [Fe(phen)_n]^2+/3+ couple play a major role in catalyzing this oscillating system.