In chemistry, the term acyl or acyl group refers to a functional group obtained from an acid by removal of a hydroxyl group.

Most commonly, the acyl group is derived from a carboxylic acid. It therefore has the formula RC(=O)-, with a double bond between the carbon and oxygen atoms (thus forming a carbonyl group), and a single bond between R and the carbon; R denotes the group that occurs in the original carboxylic acid RCOOH.

The names of acyl groups are typically derived from the corresponding acid and end in -yl, such as

• formyl (systematic name: methanoyl), derived from formic acid (systematic name: methanoic acid),
• acetyl (systematic name: ethanoyl), derived from acetic acid (systematic name: ethanoic acid),
• propionyl (systematic name: propanoyl), derived from propionic acid (systematic name: propanoic acid),
• benzoyl, derived from benzoic acid,
• acryl, derived from acrylic acid.

(Note that methyl, ethyl, propyl, butyl etc. are not acyl but alkyl groups, derived from alkanes.)

Acyl groups can also be derived from other types of acids such as sulfonic acids, phosphonic acids, and some others.

Acyl groups can be used in Friedel-Crafts acylation.

External links

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• Definition of "Acyl group" from the IUPAC Gold Book (PDF file)

Functional groups

Ацил | Acyl | Grupo acilo | Acyle