.My favorite chemical reaction is very simple/complicated - the photosynthetic splitting of water with the reduction of carbon dioxide.
My favourites are two simple reactions: The trans-esterification and the esterification reactions. Both preferrably with fatty acids involved.
Biological oils and fats usually consist from triglycerides of fatty acids and glycerol with some amounts of free fatty acids (0,1 - 100%) depending on the general quality of the oil. During the trans-esterification reaction is the glycerin replaced by another alcohol, usually MeOH or EtOH by the aid of a catalyst, usually NaOMe or KOMe. This reaction turns the oil or fat from a viscous hard-combusted liqud into a fluid easily combusted thin oil. The properties of this oil are of course depending upon the lenght and unsaturation degree of the fatty acids involved, but it is nevertheless a remarkeble change taking place. The same goes for the esterification reaction, with the exceptions that there is water formed during the reaction and that there is another catalyst empoyed, usually H2SO4.
These reactions open up new political and technical perspectives, I guess that everybody is aware of how much people all over the globe that are using this reaction in order to produce heating oil and engine fuel for themselves and their customers on a small-scale basis. Not always good quality, but it still indicates that energy can be produced and consumed locally with very low carbon footprints ,also a less vunerable system than that of today. And all this thanks to these simple reactions.
My Favorite chemical reaction, when hydrocarbon components reaction with iron oxide catalyst, and the formation of iron carbide, and then separated the carbon in the form carbon nanofibers or carbon nanotubes.
My favorite reaction is the catalytic air oxidation of heavy hydrocarbon stocks such as oils, waxes, and bitumen under mild conditions. The process may convert such stocks into fractions suitable as fuels and as intermediates. Redox couples such as Co(III)/Co(II), Mn(III)/Mn(II), or Fe(III)/(II) may be used as catalysts for this purpose.
Oscillating reactions are indeed fascinating, this one in particular. They're even observed in industrial processes. The Briggs-Rauscher Reaction is not listed in "Name Reactions, 3rd ed." (Jie Jack Li, Springer, 2006). It, along with other named oscillating reactions, should be listed in future compendia. Also, is there a descriptive compendium of oscillating reactions?