What Is Benzoyl Chloride?
Benzoyl chloride, a colorless liquid with a pungent odor, is a simple aromatic acid halide derived from benzoic acid. It has a molar mass of 140.6 g/mol, with melting and boiling points of -1°C and 197°C, respectively. Its CAS number is 98-88-4.
This compound can be produced through the chlorination of benzoic acid using phosphorus pentachloride, thionyl chloride, or phosgene. Another method involves the partial hydrolysis of trichloromethylbenzene.
Properties of Benzoyl Chloride
Benzoyl chloride reacts with water to form benzoic acid and hydrogen chloride, necessitating careful storage to prevent exposure to moisture. It is toxic and can irritate the skin, eyes, and mucous membranes. Decomposition produces corrosive and highly toxic gases like hydrogen chloride and sulfur dioxide. Proper ventilation and explosion-proof equipment are essential due to the risk of forming explosive mixtures above 72°C.
Uses of Benzoyl Chloride
Benzoyl chloride is utilized in various applications, including:
1. Organic Chemistry
Its reactive thionyl chloride moiety makes it a versatile reagent in esterification reactions with alcohols and in producing benzoyl derivatives with phenol, amines, and other nucleophiles. It acts as a benzoylating agent, facilitating carbon-carbon and heteroatom bond formation. Moreover, it’s involved in the Kurtius transition for synthesizing amines, including routes to pharmaceuticals like Tamiflu, and is used in Friedel-Crafts reactions.
2. Synthesis of Substances
By reacting with sodium peroxide, benzoyl chloride can be converted into benzoyl peroxide, a radical polymerization initiator and curing agent for unsaturated polyesters. It also serves as a synthetic intermediate for dyes, chemicals, and fragrances, highlighting its importance in the chemical industry.
Other Information on Benzoyl Chloride
Legal Information
Regulated under various laws, benzoyl chloride is categorized as a flammable liquid and a deleterious substance, emphasizing the need for cautious handling and compliance with safety regulations.