J. Phys. Chem. A 2010, 114, 3741
Comment on “Mechanistic Investigations on the Belousov-Zhabotinsky Reaction with Oxalic Acid Substrate. 2. Measuring and Modeling the Oxalic Acid-Bromine Chain Reaction and Simulating the Complete Oscillatory System” Priscilla B. Machado† and Roberto B. Faria* Escola de Química, UniVersidade Federal do Rio de Janeiro, AV. Horácio Macedo, 2030, Centro de Tecnologia, Bloco E, 21941-909 Rio de Janeiro, RJ, Brazil, and Instituto de Quı´mica, UniVersidade Federal do Rio de Janeiro, AV. Athos da SilVeira Ramos, 149, CT Bloco A, Rio de Janeiro, RJ, 21941-909, Brazil ReceiVed: December 4, 2009; ReVised Manuscript ReceiVed: January 13, 2010 In the study of BZ reaction with oxalic acid, Pelle et al.1,2 considered the reaction between oxalic acid and bromic acid, which they called (R.V) in the first paper and (R23) in the second paper. In the model they proposed to simulate this BZ modified oscillating reaction (see Table 1 in ref 2), reaction R23 was also included in a subset of most important reactions to reproduce the behavior of this oscillatory system. * Corresponding author. Instituto de Química. E-mail:
[email protected]. † Escola de Química.
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(COOH)2 + HBrO3 f 2CO2 + H2O + HBrO2 When trying to reproduce the modeling results of the second paper,2 we found a problem that HBrO3 species was not formed by any reaction in the model. This poses a problem to build a program code for this model and prevents one from reproducing their results. A second problem we raise is the fact that HBrO3 is indeed a very strong acid. This was evidenced by Raman spectroscopy,3 which indicates that this acid is fully dissociated in aqueous solution at usual concentrations and acid conditions. Considering both of these aspects together, we conclude that Pelle et al.’s model2 needs some repair to be considered a valid model to explain the experimental results of this oscillating reaction. Acknowledgment. CNPq and FAPERJ for financial support. References and Notes (1) Pelle, K.; Wittmann, M.; Lovrics, K.; Noszticzius, Z.; Turco Liveri, M. L.; Lombardo, R. J. Phys. Chem. A 2004, 108, 5377–5385. (2) Pelle, K.; Wittmann, M.; Lovrics, K.; Noszticzius, J. Phys. Chem. A 2004, 108, 7554–7562. (3) Alves, W. A.; Te´llez S., C. A.; Sala, O.; Santos, P. S.; Faria, R. B. J. Raman Spectrosc. 2001, 32, 1032–1036.
JP911520F
10.1021/jp911520f 2010 American Chemical Society Published on Web 02/12/2010
