Question

Write a short note on Rosenmund reduction. Write only the chemical equation of the reaction of ethyne with water in presence of \( H_2SO_4 \) and \( HgSO_4 \).

Hint:

Rosenmund reduction is useful for selectively reducing acid chlorides to aldehydes, while ethyne hydration gives aldehydes via Markovnikov's addition.

Answer 1

Rosenmund Reduction:
In Rosenmund reduction, acid chlorides are reduced to aldehydes using hydrogen gas and palladium catalyst poisoned with barium sulfate: \[ RCOCl + H_2 \xrightarrow{Pd/BaSO_4} RCHO. \] Reaction of ethyne with water:
Ethyne reacts with water in the presence of \( H_2SO_4 \) and \( HgSO_4 \) to form acetaldehyde: \[ HC \equiv CH + H_2O \xrightarrow{H_2SO_4, HgSO_4} CH_3CHO. \]