Abstract
Experimental and numerical studies of the temporal behavior of the acidic bromate−1,4-cyclohexanedione batch reaction in the presence of Ce(SO4)2, MnSO4, or Ru(bipy)3SO4 catalyst are reported. With increasing concentration of catalyst and at [H2SO4] ≤ 1 mol/dm3 these systems show the following bifurcation sequences: uncatalyzed oscillations → clock reaction (with excitability) → catalyzed oscillations, while at [H2SO4] ≥ 1.5 mol/dm3 the sequence is uncatalyzed oscillations → catalyzed oscillations. A chemical mechanism based on kinetic measurements of some component reactions is suggested and used to simulate the experimentally found bifurcation sequences and the monotonic and nonmonotonic recovery of the system after perturbation of the excitable state. A reduced model for the bromate−CHD−catalyst system is developed and analyzed.