Laboratory Experiments of B.Sc. II Sem BT/FS/CBZ - Experiment: 8

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

 

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

 

Experiment: 8

Objective:

Benzoylation of Amines

Principle:

    Benzoylation is an acylation reaction in which the hydrogen atom of –NH₂ group is replaced by a benzoyl group (C₆H₅CO–).
    This reaction is carried out in the presence of aqueous NaOH to neutralize the HCl formed.

    The general reaction is:

C₆H₅NH₂  +  C₆H₅COCl    →    NaOHC₆H₅NHCOC₆H₅  +  HCl

This reaction is also called the Schotten–Baumann reaction.

Materials Required:

Chemicals	Apparatus
Aniline	Beaker (100 mL)
Benzoyl chloride	Measuring cylinder
Sodium hydroxide (NaOH)	Stirring rod
Distilled water	Funnel and filter paper
Ice (optional)	Conical flask

 

Procedure:

1. Dissolve 2 mL of aniline in 10 mL of 10% NaOH solution in a beaker.
2. Cool in an ice bath.
3. Slowly add 2.5 mL of benzoyl chloride dropwise while stirring.
4. Stir vigorously for 20 minutes.
5. A white solid of benzoyl derivative of aniline (benzanilide) forms.
6. Filter, wash with water, and recrystallize from ethanol.
7. Dry and note the melting point of benzanilide.

Observation Table:

Compound Used	Product Formed	Appearance	Melting Point (°C)
Aniline	Benzanilide	White crystals	~163–165 °C

 

Result:

    The benzoylation reaction of aniline was successfully carried out to yield the corresponding benzoyl derivative.

Precautions:

• Benzoyl chloride is corrosive and irritating—handle with care.
• Carry out the experiment in a well-ventilated area or fume hood.
• Maintain low temperature using ice during addition.
• Stir continuously to ensure complete reaction.