Examples

1. Acid catalyzed condensation
   1. Acid catalyzed condensation of phenol and acetone to bisphenol which is an important intermediate in manufacture of epoxy resin and polycarbonates.

      

   2. Acid catalyzed synthesis of ethyl acetate ester from ethanol and acetic acid.

      

2. Acid catalyzed dehydration of ethyl alcohol to ethylene

   

3. Hydrolysis of ester
   1. Hydrolyses of carboxylic esters to form the parent carboxylic acid and an alcohol.

      

4. Acid or base catalyzed halogenation

Ketones can be halogenated in the presence of acid or base and X₂ (X= Cl, Br).

2. Catalysis by Metal ion

Metal ions can act as catalysts. Metal ions function in different ways :

1. Metal ions can act as “super acid”. It introduces positive charge into the substrate, making it more susceptible toward nucleophilic attack.
   
   
2. Metal ions can also act as template. Metal ions are able to coordinate to more than 2 ligands and thereby bring the molecules together.
   
   
3. Metal ions can act as redox catalyst. Many metal ions can accept or donate electrons by changing their oxidation state and thereby participate in redox reaction.

Examples

1. Catalysis by Cu²⁺ ions

   Cu²⁺ ions are very effective catalysts for the hydrolysis of α-amino acid esters.

   

2. Catalysis by Mg²⁺ ions

Hydrolysis of phosphate esters is catalyzed by metal ions, usually Mg²⁺.