Cannizzaro Reaction in Organic Chemistry

Cannizzaro Reaction

This is the general form of the Cannizzaro reaction.
This is the general form of the Cannizzaro reaction. Todd Helmenstine

The Cannizzaro reaction is a redox disproportionation of aldehydes to carboxylic acids and alcohols in the presence of a a strong base.

The second reaction uses a similar mechanism with α-keto aldehydes.

The process is a redox reaction in which a hydride is transferred from one substrate to another. One of the aldehydes is oxidized to yield an acid, while the other is reduced to yield an alcohol. The Cannizzaro reaction sometimes produces unwanted byproducts in reactions involving aldehydes in basic conditions.

History

The Cannizzaro reaction takes its name from its discoverer, Stanislao Cannizzaro, who first achieved the reaction in 1853. Cannizzaro treated benzaldehyde with potassium carbonate (potash) to obtain benzyl alcohol and potassium benzoate. While Cannizzaro used potassium carbonate, the use of potassium hydroxide or sodium hydroxide is more common.