Formation of BrO₂ in the Belousov-Zhabotinsky-System Reaction of Aliphatic Alcohols with Bromate

Abstract

BrO2 was found as an intermediate in the reaction of bromate with alcohols (e.g. methanol, isopropanol, allylalcohol) or ketones (e.g. acetone). This reaction may be important for the understanding of bromate driven oscillators.

Localized Chemical Wave Emission and Mode Switching in a Patterned Excitable Medium

“…2(c)]. These parameter values agree roughly (within two or less orders of magnitude) with previous experimental estimates of rate constants k P1 and k P2 for methanol [18,20] and k P1 for formaldehyde [19].…”

“…[16]] and accounts for perturbations due to formaldehyde and methanol. Both of these triggering reagents enhance (i) production of HBrO 2 via reaction with HBrO 3 [18,19] and (ii) production of Br ÿ by reaction with Br 2 [20]. To adequately describe these processes, it is necessary to augment the original, irreversible Oregonator model to include Br 2 as an additional reactive intermediate.…”

Contribution of Malonyl Radical Control in the Classical Belousov-Zhabotinsky Reaction

“…It turns out that the measured spectrum b) is nearly identical with the Buxton and Dainton spectrum in the wavelength range from 370 to 500 nm. In the range from 500 to 600 nm there is some significant deviation, however, although earlier spectra obtained in bromate chemistry experiments in 1 M H 2 S0 4 solution [16,22,23,24] agree with the Buxton and Dainton experiment within the limit of error. One possible explanation for the observed deviation seems to be the fact that in the experiment presented here 10 M sulfuric acid is used as a solvent, and the spectrum is changed due to the formation of (HBr0 2 ) + as suggested by Zhabotinsky [25].…”

Perturbation of the Oscillatory BZ Reaction with Methanol and Ethylene Glycol: Experiments and Model Calculations

“…To understand the effect of the primary alcohol endgroups in the present paper, we study two primary alcohols, methanol (MeOH) and ethylene glycol, as perturbants. Methanol was chosen because its most important reactions in the BZ reaction were clarified by Försterling et al According to them, methanol reacts with acidic bromate in a rate-determining first step (R1; here we follow the notations of the cited paper): producing the autocatalytic intermediate bromous acid and formaldehyde. Then, in a rapid second step, formaldehyde reacts with acidic bromate to produce one more bromous acid and formic acid, which is an inert endproduct in the BZ system: In the BZ system, the autocatalytic intermediate produced in R1 and R2 takes part in the autocatalytic cycle or removes the inhibitory bromide, depending on the state of the oscillatory reaction where autocatalytic and inhibitory phases follow each other alternately.…”

“…Then, in a rapid second step, formaldehyde reacts with acidic bromate to produce one more bromous acid and formic acid, which is an inert endproduct in the BZ system: In the BZ system, the autocatalytic intermediate produced in R1 and R2 takes part in the autocatalytic cycle or removes the inhibitory bromide, depending on the state of the oscillatory reaction where autocatalytic and inhibitory phases follow each other alternately. In a reaction where only methanol and acidic bromate was present, Försterling et al could determine the rate constant of the following overall net process: which is a sum of R1, R2, and R5, the disproportionation of bromous acid: As R2 and R5 are fast reactions, the rate of the whole net process R6 is determined by R1. Thus, the HBrO 2 inflow caused by the perturbing methanol in the BZ reaction can be determined as because both R1 and R2 produce one HBrO 2 molecule.…”