The Cannizzaro reaction is a special type of organic reaction shown by aldehydes that do not have any α-hydrogen atoms (such as formaldehyde or benzaldehyde).
What happens in the reaction?
- When such aldehydes are treated with a strong base (like concentrated sodium hydroxide or potassium hydroxide), two molecules of the aldehyde react together.
- One molecule of the aldehyde is oxidized to a carboxylic acid (or its salt).
- The other molecule is reduced to an alcohol.
So, it is a disproportionation reaction (the same compound undergoes both oxidation and reduction).
Key Points
- Requires aldehydes without α-hydrogens.
- Takes place in concentrated alkali.
- Produces a mixture of alcohol and carboxylic acid (or its salt).
In short: The Cannizzaro reaction is the base-induced disproportionation of non-enolizable aldehydes into an alcohol and a carboxylic acid.