1. Friedel-Crafts Alkylation: This reaction involves the alkylation of an aromatic ring, meaning the addition of an alkyl group (R-group) to the aromatic ring. This is achieved by reacting an aromatic compound with an alkyl halide (RX) in the presence of a Lewis acid catalyst, typically aluminum chloride (AlCl₃).

2. Friedel-Crafts Acylation: This reaction involves the acylation of an aromatic ring, meaning the addition of an acyl group (R-C=O) to the aromatic ring. This is achieved by reacting an aromatic compound with an acyl halide (RCOCl) in the presence of a Lewis acid catalyst, typically aluminum chloride (AlCl₃).

Further classifications:

While the above two are the main types, there are further classifications within each type depending on the specific reagents and reaction conditions. For instance,

* Intramolecular Friedel-Crafts Reactions: These involve the reaction of a single molecule containing both an aromatic ring and a suitable alkyl or acyl group, leading to ring closure.

* Intermolecular Friedel-Crafts Reactions: These involve the reaction of two separate molecules, one containing an aromatic ring and the other containing an alkyl halide or acyl halide.

In summary, there are two primary types of Friedel-Crafts reactions: alkylation and acylation. Each type can be further categorized based on the specific reaction conditions and the nature of the reagents involved.