Electrophilic halogenation

In organic chemistry electrophilic halogenation is a type of halogenation. This chemical reaction is typical of aromatic compounds. This type of halogenation is a very useful method for adding substituents to an aromatic system.

An example is the chlorination of benzene:

Overall: C₆H₆ + Cl₂ → C₆H₅Cl + HCl

A few types of aromatic compounds, such as phenol, will react without a catalyst, but for typical benzene derivatives with less reactive substrates, a Lewis acid catalyst is required.

Typical Lewis acid catalysts include AlCl₃, FeCl₃, FeBr₃, and ZnCl₂. These work by forming a highly electrophilic complex which attacks the benzene ring.