Alkylation is the process of substituting an alkyl group into a benzene ring, replacing a hydrogen on the ring with a group like methyl or ethyl. 

Alkylation of benzene can be catalyzed by a number of substances, including:

• Aluminum chloride: A common catalyst for the Friedel-Crafts alkylation of benzene. Aluminum chloride acts as a Lewis acid, coordinating with halogens to generate an electrophile. 
• Fluorinated alumina: Catalyzes the alkylation of benzene with propylene. 
• Methyl- and ethylsilanes: Catalyze the alkylation of benzene with ethylene and propylene. 
• Acidic zeolite catalysts: Such as mordenite, which can be used to alkylate benzene with 1-dodecene. 
• Boron trifluoride: Catalyzes the alkylation of benzene with 2-propanol, forming a carbocation intermediate that attaches to the benzene ring