Acid catalysis

In acid catalysis and base catalysis a chemical reaction is catalyzed by an acid or a base. The acid is the proton donor and the base is the proton acceptor. Typical reactions catalyzed by proton transfer are esterfications and aldol reactions. In these reactions the conjugate acid of the carbonyl group is a better electrophile than the neutral carbonyl group itself. Catalysis by either acid or base can occur in two different ways: specific catalysis and general catalysis.

Use in synthesis

Acid catalysis is mainly used for organic chemical reactions. There are many possible chemical compounds that can act as sources for the protons to be transferred in an acid catalysis system. A compound such as sulfuric acid, H₂SO₄, can be used. Usually this is done to create a more likely leaving group, such as converting an OH group to a H₂O⁺ group, which can then be eliminated as water (H₂O). Acids specifically used for acid catalysis include hydrofluoric acid (in the alkylation process), phosphoric acid, toluenesulfonic acid, polystyrene sulfonate, heteropoly acids, zeolites and graphene oxide.