Laboratory Experiments of B.Sc. II Sem BT/FS/CBZ - Experiment: 9

  Laboratory Experiments of B.Sc. II Sem BT/FS/CBZ

 

Dr. Navdeep Sharma
Institute of Sciences
SAGE University, Indore (M.P.)

 

Experiment: 9

Objective:

Preparation of Tribromophenol by Bromination of Phenol.

Principle:

Phenol is a activated aromatic compounds. Due to the presence of electron-donating –OH  group, it undergo electrophilic substitution readily with bromine, even in aqueous solution.

The reaction is:

C₆H₅OH  +  3Br₂    →    C₆H₂Br₃OH  +  3HBr

This results in white precipitates of 2,4,6-tribromophenol.

Materials Required:

Chemicals	Glassware/Equipment
Phenol	Beaker (100 mL)
Bromine water	Measuring cylinder (10/25 mL)
Distilled water	Glass rod
Ice (optional)	Filter paper and funnel

Procedure:

1. Take 1 mL of phenol in a beaker.
2. Add 20 mL of distilled water and stir to dissolve.
3. Slowly add 10 mL of bromine water dropwise with constant stirring.
4. A white precipitate of 2,4,6-tribromophenol will form.
5. Filter the precipitate, wash with cold water, and dry it between filter paper.
6. Record the melting point of the dried product.

Observation Table:

Compound Used	Product Formed	Appearance	Melting Point (°C)
Phenol	2,4,6-Tribromophenol	White precipitate	~95 °C

Result:

The bromination of phenol was successfully carried out, and the corresponding tri-brominated products were obtained as white precipitates.

Precautions:

• Handle bromine water carefully (toxic and corrosive).
• Use gloves and work in a well-ventilated area or fume hood.
• Add bromine water slowly to avoid excess reaction.
• Use dilute acid with aniline to prevent oxidation and side reactions.