Reactions of malonyl radicals with inorganic bromine species (oxidation numbers -1 to +5) of the Belousov-Zhabotinsky (BZ) reaction are investigated in 1 M sulfuric acid medium by electron spin resonance spectroscopy in continuous-flow experiments. A very high reaction rate is found for BrO2• (k7 ∼ 5 × 109 M-1 s-1), followed by Br2 and HOBr (k9 < 1.5 × 108 M-1 s-1 and k8 < 1 × 107 M-1 s-1, respectively). At high concentrations acidic bromate and bromide have some effect too, but this is probably due to indirect reactions. The results indicate that malonyl radical plays an important role as a second control intermediate besides bromide ion in the oscillatory mechanism of the BZ reaction.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry