Aluminum Chloride (AlCl3) is used as a Lewis acid catalyst for a variety of reactions. The most well-known application of AlCl3 is in Friedel-Crafts reactions. Friedel-Crafts alkylations generally only require a catalytic amount of AlCl 3, whereas Friedel-Craftacylations require greater than one equivalent of AlCl 3. This is because the Lewis acidity of AlCl 3 results in strong complexes with carbonyl groups.