The BZ Reaction: Experimental and Model Studies in the Physical Chemistry Laboratory

Abstract

The paper illustrates integrated physical chemistry-computational lab experiments at the tertiary level on the "classic" Belousov-Zhabotinsky (BZ) oscillating reaction. The complete work was designed for studying the behavior of the Ce4+/Ce3+- and Fe(phen)32+/Fe(phen)33+-catalyzed BZ systems and developing a kinetic model to interpret the experimental data. The students prepared the appropriate reactant mixtures and followed spectrophotometrically the absorbance of Ce4+ and Fe(phen)32+ ions. Then they plot the period of oscillation as a function of the initial concentration of any one of the mixture components observing in particular the difference in the dependence of the oscillation period on the [Ce4+]o and [Fe(phen)32+]o respectively. These differences suggest that the two redox couples catalyze the BZ reaction by different mechanisms. A kinetic mathematical model based on the FKN mechanism for the cerium-catalyzed reaction is presented and discussed. The numerical intergration solutions of the resulting rate equations show that the model accounts satsfactorily for the oscillations of the Ce4+/Ce3+-catalyzed system but fails to reproduce the experimental behavior of the system catalyzed by the couple Fe(phen)32+/Fe(phen)33+. It has been proved that these integrated chemistry-computational lab experiments are a powerful tool in stimulating student interest in physical chemistry and in showing the importance of chemical kinetics in the elucidation of reaction mechanism

Kinetic Determination of Silver Ion by Its Perturbation on Belousov-Zhabotinskii Oscillating Chemical Reaction Using Potentiometric Method

“…[2][3][4][5][6] Zhabotinskii obtained a linear correlation between the reactant concentration and the period of the B-Z reaction, and proposed the use of this phenomenon for chemical analysis. 7 The B-Z reaction has been of interest to a few analytical chemists who have designed kinetic methods of analysis based on the reaction.…”

“…[9][10][11][12] Tyson et al determined Hg(II) and Tl(I) in a double-line flow-injection manifold including a 30 µL flow cell and UV-VIS spectrophotometer. 13 Several other researchers have improved on the idea by adding different catalysts or inhibitors to the reaction for the determination of Fe(CN)6 [3][4][5][6][7][8][9][10][11][12][13][14]15 and Mn(II). 16 Recently, oscillating systems involving no halogen compound (particulary the CuSO4-catalyzed reaction of hydrogen peroxide with thiocyanate ion) have aroused increasing attention.…”

Quantitative similarity assessment of non-linear chemical fingerprint of traditional Chinese medicine by similarity system theory

“…For example, an improved kinetic model about the Ce(IV)/Ce(III)-catalyzed BelousovZhabotinsky (B-Z) reaction contains 80 elementary steps and 26 different chemical species [22]. Although there are many elementary steps, the reaction mechanism may be summed into two main processes, namely inductive and oscillatory processes.…”

Probing the oscillating Belousov-Zhabotinskii reaction with micrometer-sized electrodes: the effect of C, Pt, and Au

“…The BZ reaction is the oxidation of an easily brominated organic substrate catalyzed by a metallic ion in a strongly acidic medium [25]. Three major stages are considered in the reaction scheme: (1) reactions between oxybromine species; (2) autocatalytic oxidation of a metallic ion in the presence of bromate and HBrO2; and (3) reduction reactions of the catalyst and the organic substrate coupled to bromide and CO2 production [26]. A detailed analysis of the BZ reaction is complicated due to several stages and participating reactants.…”