Question

Write a short note on the Perkin reaction.

Answer 1

Hint: Organic reactions are the reactions involving organic compounds. Organic compounds are formed from carbon and its derivatives. Perkin reaction is also an example of organic reaction.

Complete step by step answer:
Perkin reaction is an organic reaction which is used to make cinnamic acids. It gives $\alpha ,\beta - $ unsaturated aromatic acid by the aldol condensation of an aromatic aldehyde and acid anhydride. This reaction occurs in the presence of alkali, which acts as a base catalyst in the reaction. So basically this is an aldol reaction.
Reaction:

The mechanism of reaction:

The mechanism of this reaction is long. It starts from the attacking of base on anhydride resulting in carbanion. Now this anion attacks on the carbon of aldehyde. This produces an intermediate and finally it produces unsaturated anhydride with the elimination of hydroxyl groups. Now the product is hydrolyzed and we finally get $\alpha ,\beta - $ unsaturated acid.
Note:
The mechanism of this Perkin’s reaction is not universally accepted due to some variations in mechanism of the reaction. It includes reactions between Aromatic aldehydes, aliphatic acid anhydride and the alkali salt.