Happohalideissa

Happohalideissa, often translated as acid halides, are a class of organic compounds characterized by a carbonyl group directly bonded to a halogen atom. The general formula for an acid halide is R-CX=O, where R represents an alkyl or aryl group, and X is a halogen, typically chlorine (Cl), bromine (Br), or iodine (I). Acyl chlorides, where X is chlorine, are the most common and reactive type of acid halide.

These compounds are derived from carboxylic acids by replacing the hydroxyl group (-OH) with a halogen atom. This transformation significantly increases the reactivity of the carbonyl carbon towards nucleophilic attack due to the electron-withdrawing nature of the halogen. This increased reactivity makes acid halides valuable intermediates in organic synthesis.

Happohalideissa readily undergo nucleophilic acyl substitution reactions. They react vigorously with water to form the corresponding carboxylic acid and a hydrogen halide. Reactions with alcohols produce esters, and reactions with amines yield amides. They can also be reduced to aldehydes or primary alcohols. Due to their high reactivity, acid halides are typically prepared and used in situ or stored carefully to prevent decomposition. Their synthesis often involves reagents like thionyl chloride (SOCl2) or phosphorus pentachloride (PCl5) acting on carboxylic acids.