Question

Bisphenol A is made on a large scale by a condensation of phenol with acetone. Suggest an appropriate catalyst, and propose a mechanism for this reaction. (Hint: This is a condensation because three molecules are joined with loss of water. The mechanism belongs to another class of reactions though.)

Short answer

complete mechanism for the reaction

Step-by-step solution

Bisphenol A (BPA)

It is a common intermediate in polyester and polyurethane synthesis. BPA is primarily used in the production of polycarbonate plastics. BPA enhances rigidity when added to plastic resins.

Condensation polymerization

In this process, a large number of monomer molecules combine together usually with the loss of simple molecules like water, alcohol, ammonia, carbon dioxide, hydrogen chloride etc., to form a polymer in which the molecular formula of the repeat unit is not the same as that of the monomer.

Mechanism

The reaction is catalyzed by a strong acid such as hydrochloric acid (HCl).

This reaction proceeds via electrophilic attack of the proton from the acidic catalyst to the acetone molecule.

In the final step, loss of water molecule takes place to give the final product as bisphenol A (BPA).

complete mechanism for the reaction