Cannizzaro Reaction
The disproportionation of an aldehyde with no alpha hydrogen under concentrated alkali into an alcohol and a carboxylate.
Formula / equation
2RCHO + OH⁻ → RCH₂OH + RCOO⁻
Unit
Dimensionless
In depth
With no alpha hydrogen available, the aldol pathway is blocked, so hydroxide adds to the carbonyl and the resulting alkoxide transfers a hydride to a second aldehyde molecule. One molecule is thereby oxidised and the other reduced.
Examples in the real world
Benzaldehyde with concentrated NaOH giving benzyl alcohol and sodium benzoate; methanal behaves the same way.