MODELING COMPLEX TRANSIENT OSCILLATIONS FOR THE BZ REACTION IN A BATCH REACTOR

The recent observations of transient complex oscillations in the Belou sov-Zhabotinsky (BZ) reaction in a batch reactor are confirmed and an attempt is made to model this behavior using the Gyorgyi-Field mechani sm (an extension of the classic Field-Koros-Noyes model). It is seen t hat the concentration of bromomalonic acid plays an important role, ac ting somewhat like a ''slowly-varying parameter,'' causing the system to sweep through a region of oscillatory response even in the absence of reactant consumption. Complex behavior is not observed in the model if the usual ''pre-equilibrium'' assumption in made for the intermedi ate species BrO2 but does arise if a full steady-state approximation i s applied to this radical. These results may bring into question some assumptions made in the usual treatment of the cerium-catalyzed BZ sys tem in closed reactors. (C) 1997 American Institute of Physics.