Question

A compound X is formed by the reaction of carboxylic acid C₂H₄O₂ and alcohol in the presence of a few drops of H₂SO₄. The alcohol on oxidation with alkaline KMnO₄ followed by acidification gives the same carboxylic acid as used in this reaction. Give the names and structures of (a) carboxylic acid, (b) alcohol and (c) the compound X. Also write the reaction.

Answer 1

Step 1: Esterification:

As in step first, there is the reaction of a carboxylic acid ${\mathrm{C}}_2{\mathrm{H}}_4{\mathrm{O}}_2$and an alcohol in the presence of a few drops of sulphuric acid

The reaction is as follows,

${\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{l}\right)+{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\left(\mathrm{l}\right)\stackrel{{\mathrm{H}}_2{\mathrm{SO}}_4}{\to }{\mathrm{CH}}_3{\mathrm{COOCH}}_2{\mathrm{CH}}_3\left(\mathrm{l}\right)$

Step 2: Oxidation of alcohol:

In the next step, the alcohol in presence of oxidizing agent gives aldehyde as an intermediate, and then finally carboxylic acid

The reaction is as follows,

${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\left(\mathrm{l}\right)\stackrel{\mathrm{Alk}{\mathrm{KMnO}}_4}{\to }{\mathrm{CH}}_3\mathrm{CHO}\left(\mathrm{l}\right)\stackrel{{\mathrm{H}}^{+}}{\to }{\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{l}\right)$

Following are the compounds reacted and formed,

Carboxylic acid is ethanoic acid (${\mathrm{CH}}_3\mathrm{COOH}$).

Alcohol is ethanol (${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$)

X is ethyl ethanoate (${\mathrm{CH}}_3{\mathrm{COOCH}}_2{\mathrm{CH}}_3$)

Hence ethyl ethanoate is formed by the reaction of ethanol and acetic acid (ethanoic acid).