Illustrated Glossary of Organic Chemistry

Iodoform reaction: A chemical reaction in which a methyl ketone is oxidized to a carboxylate by reaction with aqueous HO^- and I₂. The reaction also produces iodoform (CHI₃), a yellow solid which may precipitate from the reaction mixture. The iodoform reaction been used as a chemical test for the presence of a methyl ketone moiety.

In this typical iodoform reaction, acetophenone (a methyl ketone) is treated with aqueous NaOH and I₂ to produce sodium benzoate and iodoform.

	+
Aqueous acetophenone + NaOH Colorless		Aqueous I2 + KI Brown (due to I3- ion)		Iodoform precipitate Yellow

The yellow precipitate confirms the presence of the methyl ketone moiety in acetophenone.