In the Friedel-Crafts acylation of benzene to produce acetophenone, the Lewis acid is consumed by fo — Aromatic Hydrocarbons Chemistry Question
Question
In the Friedel-Crafts acylation of benzene to produce acetophenone, the Lewis acid $AlCl_3$ is consumed by forming a complex with the carbonyl oxygen of the product. What is the minimum number of stoichiometric equivalents of $AlCl_3$ required relative to the acyl halide to successfully mono-acylate the benzene ring?
💡 Solution & Explanation
While typically referred to as a "catalyst," $AlCl_3$ forms a stable 1:1 complex with the resulting ketone. Therefore, 1 full equivalent (or slightly more) is required per mole of acyl chloride to drive the reaction to completion, unlike alkylation where it is truly catalytic.