Benzoyl Chloride

What is Benzoyl chloride?

Benzoyl chloride is also known as benzene carbonyl chloride. The chemical formula of benzoyl chloride is C₇H₅ClO. It is a colourless liquid, boiling point 198°,fuming in moist air. It has a pungent odour and its vapour causes profuse watering of eyes and nose. It is practically insoluble in water.

Table of Contents

• Structure of Benzoyl Chloride
• Properties of Benzoyl Chloride
• Preparation of Benzoyl Chloride
• Chemical Properties of Benzoyl Chloride
• Uses of Benzoyl Chloride
• Frequently Asked Questions

Structure of Benzoyl Chloride

Properties of Benzoyl Chloride

Preparation of Benzoyl Chloride

• Benzoyl Chloride is prepared most conveniently in the laboratory by distilling benzoic acid with phosphorus pentachloride or with thionyl chloride.

C₆H₅COOH + PCI₅  →  C₆H₅COCl  + POCl₃ + HCI

        C₆H₅COOH + SOCl₂  → C₆H₅COCl + SO₂ + HCI

• It is also produced by the action of carbonyl chloride on benzene in the presence of anhydrous aluminium chloride (Friedel Crafts reaction).

C₆H₆ + ClCOCl   →  C₆H₅COCl + HCI

• Benzoyl Chloride  is made commercially by chlorination of boiling benzaldehyde.

C₆H₅CHO  + Cl₂   → C₆H₅COCl + HCI

Chemical Properties of Benzoyl Chloride

• Benzoyl chloride is slowly hydrolysed by hot water to form benzoic acid.

C₆H₅COCl  +  H₂O  →  C₆H₅COOH + HCI

• Benzoyl chloride reacts with alcohol and phenol to form esters.

C₆H₅COCl  + C₂H₅OH  →  C₆H₅COOC₂H₅ + HCI

C₆H₅COCl  +  C₆H₅OH  →  C₆H₅COOC₆H₅ + HCI

• Benzoyl chloride undergoes Friedel Craft acylation in presence of anhydrous aluminium chloride. It reacts with benzene formed benzophenone.

C₆H₅COCl  +  C₆H₆  →  C₆H₅COC₆H₅ + HCI

Uses of Benzoyl Chloride

1. Benzoyl chloride is used in tear gases to disperse mobs.
2. Benzoyl chloride is mainly useful for the production of peroxides. 
3. It is also useful for preparation of dyes, perfumes, pharmaceuticals, and resins.
4. It is also used in photography and artificial tannin production.