Bray–Liebhafsky reaction

Bray - Liebhafsky reaction is an oscillating chemical reaction. It was described as the first such response for a homogeneous system.

History

In 1916, William C. Bray and his colleague AL Caulkins started to investigate the role of hydrogen peroxide in the oxidation of iodine or the reduction of iodate. Thereby observed Bray that the oxygen development reaction of

Not continuously but was oscillating. In 1921, Bray published his work, which described an oscillating reaction in a homogeneous medium for the first time. The publication took his time, however, little attention and let the professional audience even rejection. It was alleged that the periodic behavior would contaminants from that would create heterophase interfaces, which were then regarded as a prerequisite for the occurrence of such oscillations. Having had created the theoretical basis for oscillating reactions in the 1960s Ilya Prigogine, led Bray's former employee Herman A. Liebhafsky continued the investigation of the reaction. This reaction is therefore called Bray- Liebhafsky reaction.

Only Kumud R. Sharma and Richard M. Noyes 1976 could explain the reaction mechanism.

Reaction mechanism

The complex comprises a plurality of reaction both radical and non-radical steps also. A fundamental characteristic of the system is that H2O2 has the necessary redox potential to both I2 to IO3 according

To oxidize, and IO3 -to I2 according to

To reduce. Between these two above-mentioned reactions, the system oscillates back and forth, making simultaneous jumps in concentration of the iodide and the oxygen production ( dO2/dt ) are caused and thermal oscillations arise. An increase in temperature due to an extension of the period.

As Nettostöchiometrie the reaction following reaction can be specified

Which must be a catalyst and IO3 - present.