The Briggs-Rauscher Reaction

Although the BZ reaction is the most famous oscillating reaction, the best demonstration is the Briggs-Rauscher reaction (Briggs and Rauscher, 1973). It oscillates dependably, colorfully, and rapidly, making it an ideal classroom demonstration. 

Two recipes are often used, one with 30% hydrogen peroxide and one with 3%. We will only present the latter, because the concentrated hydrogen peroxide is not readily available both recipes work equally well. 

Pour equal volumes of solutions B and C into a beaker equipped with a magnetic stir bar. (The demonstration can be performed without mixing, but the transitions will not be as sharp as with mixing.) Add a volume of solution A equal to the sum of the volumes of solutions B and C. An amber color will appear quickly, then turn to deep blue. The blue will disappear, leaving a clear solution. Copious bubble production will accompany these changes. The sequence will repeat the period of oscillation is initially about 15 s, but it will increase until, after several cycles of oscillation, the reaction remains deep blue. 

A large amount of I2 will be produced. The beaker should be kept covered, for example, with parafilm, to keep the vapors from escaping. The solid iodine that remains at the end of the reaction should be reduced to iodide by the addition of 5 g L of sodium thiosulfate. This reduction can be quite exothermic The cold solution should be flushed down the drain with large amounts of water. 

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Cervellati R, Honer K, Furrow SD, Neddens C and Costa S. 2001. The Briggs-Rauscher reaction as a test to measure the activity of antioxidants. Helv Chim Acta 84(12) 3533-3547. 

Cervellati R, Renzulli C, Guerra MC and Speroni E. 2002. Evaluation of antioxidant activity of some natural polyphenolic compounds using the Briggs-Rauscher reaction method. J Agric Food Chem 50(26) 7504-7509. 

T. Turanyi, Rate Sensitivity Analysis of a Model of the Briggs-Rauscher Reaction, React. Kinet. Catal. Lett. 45 (1991) 235-241. 

Fig. IH.5. a) Simple and complex oscillations of 12 for the Briggs-Rauscher reaction under different conditions, b) the limit cycle and the E, I2-plane (After Boissonade and de Kepper (1980))...

Table III.B.2. New Substrates and Media for the Briggs-Rauscher Reaction...

Vukojevic, V., Sorensen, P.G., and Hynne, F., Quenching analysis of the Briggs-Rauscher reaction, J. Phys. Chem., 97, 4091-4100, 1993. 

Figure 4.5 (a) Phase portrait of an oscillation in the Briggs-Rauscher reaction. The time interval between points is 12 s. (b) Temporal evolution of u ([ ]) corresponding to phase-space behavior in part a. (Adapted from De Kepper and Epstein, 1982.)... 

Another method is based on the inhibitory effects of free-radical scavengers toward the oscillations of the Briggs-Rauscher (BR) reaction (Cervellati and others 2001). The... 

Fig. III.3. Double oscillations of the model for Briggs-Rauscher reaction (After Boissonade (1976))...

De Kepper and Epstein (1982) identified ten reactions in the Briggs-Rauscher (B-R) system. These reactions overlap those proposed by Noyes and Furrow (1982) and by Cooke (1980-2). The regions of oscillations for the initial values of I2 and 10 j" were identified. By numerical simulations oscillations were obtained. 

IIIB) Furrow, S. D Noyes, R. M. The Oscillatory Briggs-Rauscher Reaction — 1. Exami-... 

Variants of the double autocatalysis mechanism occur in the Limited Explodator model of the BZ reaction (Noszticzius et al., 1984a) and the Briggs-Rauscher oscillator (De Kepper and Epstein, 1982). 

The chlorite-iodate-arsenite oscillator was the first oscillating reaction discovered which is based upon chlorite chemistry. The BZ reaction and its relatives are bromate oscillators, while the BL and Briggs-Rauscher oscillators are iodate systems. The initial chlorite oscillator was rapidly followed by a large family of related systems58"60, which are summarized in Table 8. We note that while most of these systems contain an iodine species (I-, I2, IOf) as well as the chlorite, at least two iodine-free chlorite oscillators exist. 

Briggs-Rauscher) and bromate oscillators (Belousov-Zhabotinskii), these new reactions are chlorite oscillators. For the chlorite oscillators, Orban et al. (1982-3) have also given a preliminary classification. 

The field of oscillating reactions, or periodic reactions, or chemical clocks, came out of this background indeed quite a number of chemical systems have been described, which show this oscillating, periodic, regular behavior (Field, 1972 Briggs and Rauscher, 1973 Shakhashiri, 1985 Noyes, 1989 Pojman etal, 1994 Jimenez-Prieto etal., 1998). 

Briggs and Rauscher discovered an oscillating reaction which is identified as an iodine clock. It resembles the iodate-hydrogen peroxide reaction of Bray (1921), and has some of the elements of the reaction of Belousov, see Section III.C. The chemicals involved are ... 

Later on Briggs and Rauscher combined the hydrogen peroxide and iodate of the BL reaction with the malonic acid and manganese ions of the BZ reaction, and discovered the... 

As more chemists began to study the BZ and Bray reactions, several variants (Orban and Koros,[ 10] Bowers, et al.,[H] ) and hybrids (Briggs and Rauscher, [12]) of these reactions were developed. However, no chemical oscillators with chemistry fundamentally different from that of the two accidentally discovered prototypes were found, and one might summarize the sources of oscillatory reactions prior to I980 as ... 

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