Asüülkloriid

Asüülkloriid is a class of organic compounds derived from carboxylic acids. They are characterized by the presence of a functional group with the formula RC(O)Cl, where R is an alkyl or aryl group and Cl is a chlorine atom. These compounds are highly reactive due to the electrophilic nature of the carbonyl carbon, which is made more so by the electron-withdrawing effect of the chlorine atom.

Asüülkloriidid are typically prepared by the reaction of carboxylic acids with chlorinating agents such as thionyl chloride (SOCl2), phosphorus trichloride (PCl3), or phosphorus pentachloride (PCl5). The reaction with thionyl chloride is particularly common as the byproducts, sulfur dioxide (SO2) and hydrogen chloride (HCl), are gases and easily removed, driving the reaction to completion.

The high reactivity of asüülkloriidid makes them valuable synthetic intermediates in organic chemistry. They readily undergo nucleophilic acyl substitution reactions with a variety of nucleophiles. For example, reaction with alcohols yields esters, reaction with amines produces amides, and reaction with water results in the formation of the corresponding carboxylic acid, often accompanied by the release of hydrogen chloride. This reactivity also means they are sensitive to moisture and must be handled with care. Common examples include acetyl chloride and benzoyl chloride.