Iodoform is obtained by the action of iodine on ethanol (ethyl alcohol), or on propanone (acetone) in the presence of an alkali. This reaction is called haloform reaction, and is commonly known as iodoform test.
Step 1:
Step 2: Oxidation of ethanol to ethanal (acetaldehyde).
Step 3:Ethanal so formed undergoes iodination.
Step 4: Hydrolysis (cleavage) of Cl3CHO by alkali.
Net reaction:
Step 1:
Step 2:Iodination of acetone.
Step 3:Hydrolysis (cleavage) of Cl3.CO.CH3 by alkali.
Net reaction:
The reactions for the preparation of iodoform when Na2CO3 is used in place of NaOH are as follows:
Iodoform shows chemical behavior similar to that of chloroform, but it is less stable. Some of the typical reactions given by iodoform are:
Iodoform is used as an antiseptic. Its antiseptic property is due to the liberated iodine. However, due to its unpleasant smell, it has been replaced by other formulations containing iodine. It is used in the manufacture of certain pharmaceuticals.