the conversion of aldehyde into a mixture containing equal molar quantities of alcohol and acid in an aqueous or water-alcohol solution of alkali; for example,
2C6H5CHO + KOH → C6H5COOK + C6H5CH2OH
The Cannizzaro reaction is a redox process characteristic of aromatic and heterocyclic aldehydes as well as of aldehydes in the aliphatic series that do not contain any hydrogen atoms near the carbon, bonded with the aldehyde group. This reaction can be carried out successfully in the case of two unlike aldehydes (“crossed” Cannizzaro reaction). Thus, benzyl alcohol C6H5-CH2OH and formic acid HCOOH are produced from a mixture of benzaldehyde C6H5CHO and formaldehyde HCHO. This version of the Cannizzaro reaction is widely used for the reduction of inaccessible aldehydes into the corresponding alcohols. S. Cannizzaro discovered the reaction in 1853.