Dear Student,
The ethylation reaction of benzene involves the addition of an ethyl group on the benzene ring. Such a reaction is called a Friedel-Craft alkylation reaction. This reaction takes place in the presence of a Lewis acid.
Any Lewis acid like anhydrous FeCl3, SnCl4, BF3 etc. can be used during the ethylation of benzene. These are some of the Lewis acid other than anhydrous Aluminium chloride that can be used for during ethylatiob of benzene.
Regards,