The Belousov–Zhabotinskii Reaction: Improving the Oregonator Model with the Arrhenius Equation

Abstract

Oscillating chemical reactions (OCRs) have been known since 1828, with the Belousov–Zhabotinskii (BZ) reaction the most studied example. Initially, OCRs were considered to be special cases due to the small number detected and because the oscillatory behavior did not seem to agree with the second law of thermodynamics. However, OCRs have become increasingly important not only in chemistry, but also in biology as they are the foundation of several significant phenomena: glycolysis, nerve signal transmission, heartbeats, and so forth. The BZ reaction has been examined both experimentally and theoretically. Temporal oscillations appear in both cases, but discrepancies are found between experimental results and theoretical calculations. This article addresses the discrepancies by describing (i) a simple, clear, and inexpensive experimental procedure for carrying out the reaction and determining the oscillation period and (ii) an innovative methodology that includes the effect of temperature on the original model using the Arrhenius equation. The equations resulting from this approach can easily be solved with the help of MATLAB. In addition, a user-friendly graphical interface has been developed that highlights the effects on the oscillating system caused by changes in different parameters. The effect of the temperature generated during the reaction is also analyzed. This analysis discloses temperature variations: a relevant issue that the theoretical model does not envisage. The exercise is appropriate for upper-level physical chemistry students.