Question

Explain the following reactions.
(i) HVZ reaction.
(ii) Trans esterification
(iii) Methyl salicylate formation.

Answer 1

(i) Hell-Volhard-Zelinsky reaction(HVZ):
Aliphatic carboxylic acids containing a hydrogen react with chlorine or bromine in the presence of a small amount of red phosphorous to give a haloacids. This reaction is known as HVZ reaction.
(ii) In presence of a little acid, methyl acetate is cleaved by ethyl alcohol to form ethyl acetate.
$C{H}_{3}COOC{H}_3+C_2{H}_{5}OH\stackrel{H^{+}}{\to }C{H}_{3}COO{C}_2{H}_5+C{H}_{3}OH$
This is called 'trans esterification'.
(iii) When salicylic acid reacts with methanol in the presence of conc. sulphuric acid, methyl salicylate is formed.