The most widely practiced example of this reaction is the ethylation of benzene.
Approximately 24,700,000 tons were produced in 1999.
 (After dehydrogenation and polymerization, the commodity plastic
polystyrene is produced.) In this process,
solid acids are used as catalyst to generate the incipient carbocation. Many other electrophilic reactions of benzene are conducted, although on much smaller scale, they are valuable routes to key intermediates. The nitration of benzene is achieved via the action of the
nitronium ion as the electrophile. The
sulfonation with fuming
sulfuric acid gives
Aromatic halogenation with
iodine gives the corresponding aryl halides. This reaction is typically catalyzed by the corresponding iron or aluminum trihalide.
Friedel–Crafts reaction can be performed either as an
acylation or as an
aluminium trichloride is used, but almost any strong
Lewis acid can be applied. For the acylation reaction a
stoichiometric amount of aluminum trichloride is required.