Question

Distinguish between esterification and saponification reaction with the help of the chemical equations for each. State one use of each (i) esters, and (ii) saponification process.

Answer 1

Step 1:

When alcohol $\mathrm{R}-\mathrm{OH}$ reacts with an organic acid$\mathrm{R}-\mathrm{COOH}$ in an acidic medium produces the esters$\mathrm{RCOOR}$. This process is called esterification.

The esterification reaction can be written as:

$$\begin{gathered} {\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right)+{\mathrm{CH}}_3\mathrm{COOH}\left(\mathrm{l}\right)\stackrel{\mathrm{acid}\mathrm{catalyst}}{\to }{\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5\left(\mathrm{l}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right) \\ \mathrm{Ethanol}\mathrm{Ethanoic}\mathrm{acid}\mathrm{Ethyl}\mathrm{acetate} \end{gathered}$$

(i) Esterification reaction takes place in an acidic medium.

Step 2:

The hydrolysis of an ester in the presence of a strong alkali such as Sodium Hydroxide ($\mathrm{NaOH}$) produces alcohol and alkali salts of the acid is known as saponification.

The saponification reaction can be written as:

$$\begin{gathered} {\mathrm{CH}}_3{\mathrm{COOC}}_2{\mathrm{H}}_5\left(\mathrm{l}\right)\stackrel{\mathrm{NaOH}}{\to }{\mathrm{CH}}_3\mathrm{COONa}\left(\mathrm{l}\right)+{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}\left(\mathrm{l}\right) \\ \mathrm{Ethyl}\mathrm{acetate}\mathrm{Sodium}\mathrm{acetate}\mathrm{Ethanol} \end{gathered}$$

(i) Saponification reaction takes place in a strongly alkaline medium.

1. Esters are used to making perfumes.

2. Saponification process is used in the preparation of soap.