Question

What are Claisen schmidt condensation and Kolbe's Reaction ? Give one example of each.

Answer 1

• Claisen-Schmidt condensation $\to$
  

The reaction between an aldehyde or ketone having an alpha-hydrogen with an aromatic carbonyl compound lacking alpha hydrogen is called the Claisen–Schmidt condensation.

Ex- Synthesis of dibenzylideneacetone-

$2C_6{H}_5-CHO+C{H}_3-CO-C{H}_3\stackrel{NaOH/EtOH}{\to }\underset{\left(\text{Dibenzylideneacetone}\right)}{C_6{H}_5-CH=CH-CO-CH=CH-C_6{H}_5}$

• Kolbe's reaction $\to$
  

The Kolbe's reaction is a carboxylation chemical reaction that proceeds by heating sodium phenoxide with carbon dioxide under pressure $(100atm,125℃)$, then treating the product with an acid.

Ex- Reaction of phenol with $NaOH$ and $C{O}_2$ to form salicylic acid-

$C_6{H}_5-OH\stackrel{NaOH}{\to }{C}_6{H}_5-ONa\underset{\left(ii\right)H^{+}}{\overset{\left(i\right)C{O}_2}{\to }}\underset{\underset{\left(\text{Salicylic acid}\right)}{\text{2-Hydroxybenzoic acid}}}{C_6{H}_5\left(COOH\right)-OH}$