Reaction mechanisms
Alkylation of aromatic compounds

Industrial alkylations of aromatic hydrocarbons are carried out by acid catalysis with the formation of carbonium ions. Catalysts used in this process include :

• aluminum chloride AICI₃ ;

• HF hydrofluoric acid;

• phosphoric acid H₃PO₄ ;

• boron trifluoride BF₃ ;

• sulfuric acid H₂SO₄ .

These are two-step electrophilic substitution reactions, as described below.

• Laformation of the carbonium ion by addition of a proton from an XH acid (sulfuric acid, hydrofluoric acid, phosphoric acid, Friedel-Crafts catalyst in acid medium, modified zeolites) to the alkene used, according...