Iodoform Preparation in the lab for confirmation of presence of a ketone. Confirmation of the presence of a Ketone by the preparation of iodoform. The presence of a ketone can be confirmed by the preparation a yellow colored solid called iodoform. Secondary alcohols can be chemically reduced to a ketone using a reducing agent. The ketone that is produced can be converted to iodoform. Below is the procedure for the preparation of iodoform from acetone. Nail polish remover is acetone. The IUPAC name for acetone is called propanone.
Method of preparation
Acetone when mixed with potassium carbonate and solid iodine can produce iodoform
- Iodine crystals 5 grams
- Solid potassium carbonate 5 grams
- Propanone or Acetone 3.5 mL
CH3COCH3 + 3I2 → CI3COCH3 + 3HI
CI3COCH3 + NaOH → CHI3 + CH3COONa
Mass 5 grams of potassium carbonate K2CO3 . Dissolve in 20 mL of distilled water, taken in an Erlenmeyer flask. Stir the mixture constantly to ensure the potassium carbonate is completely dissolved. The mixture is then placed in a warm water bath, which is at about 75 to 80 degrees Celsius. Cool the solution when the reaction is complete. The yellow crystals formed is iodoform. Separate the iodoform from the mixture by filtration. Wash the iodoform with water. A small sample of the iodoform is recrystallized from alcohol. Dry the iodoform crystals.
Theoretical Yield of iodoform is 1.15 grams
The melting point of iodoform is 119 oC
Copyrights © Stan Vincent for the procedure. All rights reserved.