Acid halide

Acid Halide

An acid halide is a chemical compound that contains a halogen atom bonded to a carbonyl group. They are a type of functional group in organic chemistry, and are often used in chemical synthesis due to their reactivity.

Structure and Properties

Acid halides are characterized by the presence of a halogen atom (such as fluorine, chlorine, bromine, or iodine) bonded to a carbonyl group (C=O). This gives them the general formula RCOX, where R is an organic group and X is a halogen. The bond between the carbonyl carbon and the halogen is polar, with the halogen being more electronegative. This results in a partial positive charge on the carbonyl carbon, making it susceptible to nucleophilic attack.

Synthesis

Acid halides can be synthesized from carboxylic acids using a halogenation reaction. This typically involves treating the carboxylic acid with a halogenating agent such as thionyl chloride (for acid chlorides) or phosphorus tribromide (for acid bromides).

Reactions

Due to their high reactivity, acid halides are often used in chemical synthesis. They can react with alcohols to form esters, with amines to form amides, and with water to form carboxylic acids. They can also undergo Friedel-Crafts acylation, a type of electrophilic aromatic substitution reaction.

Safety

Acid halides can be hazardous due to their reactivity and the potential for the release of toxic halogen gases. Proper safety precautions should be taken when handling these compounds, including the use of personal protective equipment and adequate ventilation.

See Also

• Carboxylic acid
• Halogenation
• Functional group
• Chemical synthesis