Chaos within Chemistry: The Briggs-Rauscher Reaction
a. Goal(s) of project
b. Our application/rendition of chemical chaos
c. Description of experiment - Briggs-Rauscher reaction
II. Running the Reaction (actual 'wet' experiment)
a. execute reaction
b. describe what is occuring
-equations, chemicals used, functions of chemicals
c. how this is chaotic
III. Math behind the Reaction
b. interpreting the oscillations of color
c. discussing chemical INequilibrium vs. equilibrium
which is the one we are experiencing
a. summary of processes
c. interpretation of the mechanisms involved
d. "What sets this reaction apart from a regular reaction"
e. Other instances in which this scenario exists
Strogatz, Steven. Nonlinear dynamics and Chaos : with applications to physics, biology, chemistry, and engineering . Reading, MA: Addison-Wesley Publishers, 1994.
International Symposium on Synergetics, Evolution of order and chaos in physics, chemistry, and biology : proceedings of the International Symposium on Synergetics at Schloss Elmau, Bavaria. New York: Springer-Verlag , 1990.
Toda, Mikito. Geometric structures of phase space in multi-dimensional chaos : Applications to chemical reaction dynamics in complex systems. New York: Wiley Publishers, 2005.
Prigogine, I.. Resonances, instability, and irreversibility . New York: Wiley Publishers, 1997.
Epstein, Irving R.. "Chemical Chaos. (unpredictable reactions)." Chemistry and Industry 15 March 2000 November 1 2007 <http://findarticles.com/p/articles/mi_hb5255/is_199103/ai_n20268957/print>.
Wang, Hongli and Qian-Shu Li. "Ensemble simulation study of chaos in a chemical model." PCCP 5 April 2005 1 November 2007 .
This research project will focus on the chaos that occurs throughout select chemical reactions. These reactions, catalogued as oscillating chemical reactions, have a multitude of mechanisms occurring simultaneously; not only do the color of the solution vary, but the voltage, ratios of products and concentration of reactants take an irregular course. Besides interpreting what is happening during the reaction chemically, we will also attempt to interpret the quantitative data of the process in mathematical terms. In turn, it will be feasible to relate the mathematical values derived from the reaction to the chaotic, oscillatory behavior of this particular experiment. Ultimately, this dissertation will discuss the different methods to approaching the Briggs-Rauscher reaction as well as derive certain characteristics in chemistry that are often overlooked as being too complex.
The Briggs-Rauscher reaction was created, interestingly enough, by two high school chemistry teachers: Thomas Briggs and Warren Rauscher. Its intriguing oscillating chemical system has sparked much interest in the field of chemical inequilibrium and stabilization. Most elementary and fundamental chemistry is taught so that reactions are thought to be run to completion—with no aspects mentioned concerning reaction rates, concentration changes and inequilibria. Moreover, this reaction is ideal for demonstration a chemical change inside of a system. Specifically, the freshly prepared colorless solution slowly turns an amber color, then changing to a very dark blue. This slowly fades to clear and the process repeats. Usually, this change in color occurs about ten times, before finally coming to completion as a dark blue liquid that smells strongly of iodine.
Before Thomas Briggs and Warren Rauscher discovered their oscillating reaction in 1972, it must be noted that they possessed knowledge of previous less effective and distinguished similar reactions. For instance, the first homogenous oscillating chemical reaction was reported by W.C. Bray in 1921, by means of combining hydrogen peroxide and iodate in acidic solution. Later, B.P. Belousov of the Soviet Union generated the Beloousov-Zhabotinsky (BZ) reaction in 1958, which wasn’t published, due to its’ obscurity, by A.M. Zhabotinsky in 1964. The underlying achievement and distinction that parallels Briggs’ and Raucher’s work is the replacement of bromate by iodate and adding hydrogen peroxide. Finally, a starch indicator was what made this reaction such a colorful oscillation series.
The initial conditions, while appearing to be simple laboratory reagents, react to produce exotic and unconventional results. The key to the complexity of the BR reaction lies within reaction rates; while some decompositions occur slowly, some other productions can form rapidly and vice versa. In this, we see erratic and oscillatory behavior, visible in the vibrant color changes. The initial aqueous (dissolved in water) solution contains hydrogen peroxide, an iodate, divalent manganese, sulfuric acid or perchloric acid, and an organic compound with an enolic hydrogen that slowly reduces the free iodine to iodide. With starch (optional), there is an indication of an abrupt increase in the concentration of iodide ion from amber to dark blue.
Essentially, there are two components to this entire reaction of 11 mechanisms. For one, a non-radical process occurs through the slow consumption of free iodine by malonic acid in the presence of iodate. This step generates an iodide intermediate ion. Secondly, a radical process occurs in which a fast reaction between manganese and free radical intermediates, in turn converting hydrogen peroxide and iodate to free iodine and oxygen. This process is limited, however, to the rate of consumption of iodine. Overall, while part 1 is occurring at its peak speed, part 2 is not, and vice versa.
IO3(-) + 2H2O2 + CH2(COOH)2 + H(+) ICH(COOH)2 + 2O2 + 3H2O
YOUTUBE VIDEO MADE ON 12/4/07 http://www.youtube.com/watch?v=kgdDvAXZi7E