Investigation of Radical Reactions Important in the Gyoergyi-Turanyi-Field Model of the Belousov-Zhabotinskii Reaction

Article abstract of DOI:10.1021/j100172a040

In the Gyoergyi-Turanyi-Field (GTF) model of the Belousov-Zhabotinskii (BZ) reaction, malonyl radicals (MA^.) and bromomalonyl radicals (BrMA^.) are assumed to be important intermediates.The hydrogen abstraction reactions MA^. + BrMA -> MA + BrMA^. (a) and BrMA^. + MA -> BrMA + MA^. (b) (MA, malonic acid; BrMa, bromomalonic acid) transfer from free-radical nature of the malonyl species to the bromomalonyl species and vice versa.The rates of these two reactions determine in part the relative importance of these radical intermediates.Another key radical reaction is BrMA^. + Ce⁴⁺ + H2O -> BrTTa + Ce³⁺ (c) (BrTTA, bromotartronic acid), which is a source of Br^- through decomposition of BrTTA in the model.It has been deduced from ESR and spectrophotometric experiments that reactions a-c do not contribute to the chemistry of the BZ reaction.Numerical integration of the GTF rate equations, omitting reactions a-c, shows no oscillation in BZ systems with high initial concentrations of BrMA.Experimentally, these systems exhibit oscillations with no induction period.