Briggs-Rauscher Mechanism: The Chemical Color Clock

The reactions involved in the Briggs–Rauscher (BR) mechanism are the following:
where is malonic acid.
Suppose these reactions take place in an open reactor. Then, under certain circumstances, the color of the solution in the reactor shows regular oscillation between amber and dark blue.
This Demonstration simulates the BR mechanism in a flow reactor and shows that the rate expressions given in [1] predict the observed topology of the "cross-shaped phase diagram" in which both bistability and oscillations appear as the initial condition (i.e. initial condition 1 or 2) and the input flows of the reactant species and (i.e. and ) are varied.
The Demonstration shows the presence of a limit cycle for specific values of and (e.g. and ) and sustained oscillations for the compositions. Time series for the compositions of , , , and (i.e. , , , and , respectively) are shown in green, brown, magenta, and blue, respectively. For other values of and (e.g. and ), one can see bistability. Indeed, two steady states are observed depending the choice of the initial condition (i.e. initial condition 1 or 2). Initial condition and steady state are shown by the blue and green dots, respectively.


  • [Snapshot]
  • [Snapshot]
  • [Snapshot]


The members of the sequence are the compositions of , respectively. The concentration of is taken as a constant equal to . In the program, the symbols , K1, K2, …, and k1, k2, … are the different rate constants and constants appearing in the rate laws (see [1] for details).
In the program, X10, X20, …, X100 are the 10 concentrations of the various components in the feed stream of the open reactor. The reactor’s residence time equal to ; the Mathematica variable A is a constant equal to .
[1] P. De Kepper and I. R. Epstein, "A Mechanistic Study of Oscillations and Bistability in the Briggs–Rauscher Reaction," Journal of the American Chemical Society, 104(1), 1982 pp. 49–55.
[2] M. M. Thomas, "The Briggs–Rauscher Reaction: Chemistry Clock in Color," Mathematica in Education and Research, 11(1), 2006 pp. 129–137.
    • Share:

Embed Interactive Demonstration New!

Just copy and paste this snippet of JavaScript code into your website or blog to put the live Demonstration on your site. More details »

Files require Wolfram CDF Player or Mathematica.

Mathematica »
The #1 tool for creating Demonstrations
and anything technical.
Wolfram|Alpha »
Explore anything with the first
computational knowledge engine.
MathWorld »
The web's most extensive
mathematics resource.
Course Assistant Apps »
An app for every course—
right in the palm of your hand.
Wolfram Blog »
Read our views on math,
science, and technology.
Computable Document Format »
The format that makes Demonstrations
(and any information) easy to share and interact with.
STEM Initiative »
Programs & resources for
educators, schools & students.
Computerbasedmath.org »
Join the initiative for modernizing
math education.
Powered by Wolfram Mathematica © 2014 Wolfram Demonstrations Project & Contributors  |  Terms of Use  |  Privacy Policy  |  RSS Give us your feedback
Note: To run this Demonstration you need Mathematica 7+ or the free Mathematica Player 7EX
Download or upgrade to Mathematica Player 7EX
I already have Mathematica Player or Mathematica 7+