Transition from Low to High Iodide and Iodine Concentration States in the Briggs–Rauscher Reaction: Evidence on Crazy Clock Behavior

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 122; no. 2; pp. 482 - 491
• Main Authors: Pagnacco, Maja C, Maksimović, Jelena P, Potkonjak, Nebojša I, Božić, Bojan Đ, Horváth, Attila K
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 18.01.2018
• ISSN: 1089-5639; 1520-5215; 1520-5215
• DOI: 10.1021/acs.jpca.7b11774

The Briggs–Rauscher reaction containing malonic acid may undergo a sudden transition from low (state I) to high iodide and iodine (state II) concentration states after a well-defined and strongly reproducible oscillatory period. This study clearly shows that even though the time-dependent behavior of the oscillatory state is reproducible, the time lag necessary for the appearance of the state I to state II transition after the system leaves the oscillatory state becomes irreproducible for an individual kinetic run. This crazy clock behavior of the state I to state II transition is identified by repeated experiments in which stirring rate is taken as a control parameter and all other parameters such as initial conditions, temperature, vessel surface, and the age of solution were kept constant. Surprisingly, a better stirring condition does not make the transition reproducible; it simply does not allow the transition to happen at all. The proposed mechanism, additional explanations, and proposals for this irreproducibility of state I to state II transition have been presented. Considering the fact that the number of crazy clock reactions is only a few, this study may contribute to a better understanding of fundaments of this phenomenon.