In
chemistry, 'acylation' is the process of adding an
acyl group to a compound. The compound providing the acyl group is called the 'acylating agent'.
Because they form a strong
electrophile when treated with some metal
catalysts,
acyl halides are commonly used as acylating agents. For example,
Friedel-Crafts acylation uses
acetyl chloride (ethanoyl chloride),
CH3COCl, as the agent and aluminum chloride (AlCl
3) as a catalyst to add an ethanoyl(
acetyl) group to
benzene:

Friedel-Crafts acylation of benzene by ethanoyl chloride
The mechanism of this reaction is
electrophilic substitution.
Acyl halides and
anhydrides of
carboxylic acids are also commonly used acylating agents to acylate
amines to form
amides or acylate
alcohols to form
esters. The amines and alcohols are
nucleophiles; the mechanism is
nucleophilic addition-elimination.
Succinic acid is also commonly used in a specific type of acylation called ''succination''. ''Oversuccination'' occurs when more than one succinate adds to a single compound. An industrial example of acylation in the synthesis of
aspirin, in which
salicylic acid is acylated by
acetic anhydride.
Mechanism of Friedel Crafts:

Friedel-Crafts-Acylierung.png
See also
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acetyl
★
ketene
★
indicator
★
chemical synthesis
References
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NIH Thesaurus