Question

Write short notes on: (i) Williamson’s ether synthesis
(ii) Fermentation
(iii) To obtain methyl alcohol from pyroligneous acid

Hint:

Remember: Williamson’s method = ethers, fermentation = ethanol, pyroligneous acid = source of methanol.

Answer 1

(i) Williamson’s Ether Synthesis:
It is a laboratory method for the preparation of ethers. In this method, an alkoxide ion reacts with a primary alkyl halide to produce an ether.
\[ R\!-\!ONa + R'X \; \longrightarrow \; R\!-\!O\!-\!R' + NaX \] Example: \[ C_2H_5ONa + CH_3I \; \longrightarrow \; C_2H_5OCH_3 + NaI \] This method is widely used for the synthesis of symmetrical and unsymmetrical ethers. (ii) Fermentation:
Fermentation is a biochemical process in which sugars such as glucose and sucrose are converted into ethanol and carbon dioxide by the action of enzymes (zymase) produced by yeast.
\[ C_6H_{12}O_6 \; \xrightarrow{\text{zymase}} \; 2C_2H_5OH + 2CO_2 \] Fermentation is the basis of alcoholic beverages and bioethanol production. (iii) To obtain methyl alcohol from pyroligneous acid:
Pyroligneous acid is obtained by the destructive distillation of wood. It contains acetic acid, acetone, and methyl alcohol as impurities.
On neutralization and distillation, methyl alcohol is separated as the main product. Thus, wood spirit (methyl alcohol) is commercially obtained from pyroligneous acid. Conclusion:
These processes highlight important laboratory and industrial methods for preparing ethers, alcohols, and biofuels.