Question

5. Write the equations involved in the following reactions:

(i) Reimer-Tiemann reaction

(ii) Kolbe’s reaction​

Answer 1

Answer:

(i) Reimer-Tiemann reaction → When phenol is treated with chloroform in the presence of sodium hydroxide, a −CHO group is introduced at the ortho position of the benzene ring. This reaction is known as the Reimer-Tiemann reaction. The intermediate is hydrolyzed in presence of alkalis to produce salicylaldehyde.

(ii) Kolbe's reaction → When phenol is treated with sodium hydroxide, sodium phenoxide is produced. This sodium phenoxide when treated with carbon dioxide, followed by acidification, undergoes electrophilic substitution to give ortho-hydroxybenzoic acid as the main product. This reaction is known as Kolbe's reaction.