Describe the products of the following Friedl-Crafts substitution and explain the role of the AlCl3 in the reaction: C6H6 + CH3C(O)Cl + AlCl3 = ?

C6H6 + CH3C(O)Cl = C6H5C(O)CH3 + HCl

This is an example of an electrophilic aromatic substitution reaction, with the product being a ketone. The AlCl3 serves as a catalyst, converting the acyl chloride into a stronger electrophile to encourage attack by the relatively weakly nucleophilic benzene.

AlCl3 is electron-deficient so can act as a Lewis acid and accept a pair of electrons from the acyl chloride.

CH3C(O)Cl + AlCl3 = CH3C+(O) + Al-Cl4 

The CH3C+(O) now has a stronger delta + than the acyl chloride, activating it towards electrophilic substitution by the benzene.

The AlCl3 regenerated at the end of the reaction.