Acylium ion

Definition

An acylium ion is a positively charged ion with the general formula RCO+, where R is an alkyl or aryl group, and it forms during the Friedel–Crafts acylation reaction when an acyl chloride reacts with a Lewis acid catalyst. It acts as an electrophile in electrophilic aromatic substitution reactions, attacking the aromatic ring to form a new carbon-carbon bond.

Related terms

Electrophilic Aromatic Substitution: A reaction where an aromatic ring undergoes substitution by an electrophile, leading to the replacement of a hydrogen atom attached to the ring.

Friedel–Crafts Acylation: A process that introduces an acyl group into an aromatic ring via electrophilic aromatic substitution using an acyl chloride and a Lewis acid catalyst.

Lewis Acid: A chemical compound that can accept an electron pair from a donor compound, often used as a catalyst in organic reactions such as Friedel–Crafts Acylation