[paulhao]

Why stoichiometric Catalyst in Friedel Crafts Acylation is important?

Some literature says that the substrate and even the product would form complexes with AlCl3. How is this fact possible? and what complexes would it  form?

Also, is there any reason why we should have a right amount of AlCl3 catalyst?

[kriggy]

Its because the formed ketone can form some coordination complex with the AlCl₃ and deactivate it for further reactions. This is not the case for the FC alkylation. I never personaly run any of those so it might be different for different substrates but this is what we were told in class and organic chemistry portal supports it as well
https://www.organic-chemistry.org/namedreactions/friedel-crafts-acylation.shtm