Catalytic cycle
In
Since catalysts are regenerated, catalytic cycles are usually written as a sequence of
A catalytic cycle is not necessarily a full reaction mechanism. For example, it may be that the intermediates have been detected, but it is not known by which mechanisms the actual elementary reactions occur.
Precatalysts
Precatalysts are not catalysts but are precursors to catalysts. Precatalysts are converted in the reactor to the actual catalytic species. The identification of catalysts vs precatalysts is an important theme in catalysis research.
The conversion of a precatalyst to a catalyst is often called catalyst activation. Many metal halides are precatalysts for
Often catalytic cycles show the conversion of a precatalyst to the catalyst.
Sacrificial catalysts
Often a so-called sacrificial catalyst is also part of the reaction system with the purpose of regenerating the true catalyst in each cycle. As the name implies, the sacrificial catalyst is not regenerated and is irreversibly consumed, thereby not a catalyst at all. This sacrificial compound is also known as a stoichiometric catalyst when added in
References
- ^ Kinetics of catalytic reactions 2005 M. Albert Vannice
- .