Question

Write the equation involved in the following reactions:
(i) Reimer-Tiemann reaction (ii) Kolbe's reaction

Answer 1

• (i) Reimer-Tiemann reaction $\to$ 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 $\to$ 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.