Question

How will you bring out the following conversion :
(i) Acetyl chloride to Acetaldehyde
(ii) Methanal to Ethanal.

Answer 1

How will you bring out the following conversion :
(i) Acetylchloride to acetaldehyde :

Rosenmund's reaction:

$H_2$ gas is passed through a boiling solution of acetyl chloride in xylene in the presence of $Pd$ catalyst supported by $BaS{O}_4$. The catalyst is poisoned by sulphur or quinoline. This avoids further reduction of acetaldehyde to ethyl alcohol

$C{H}_3-\underset{\underset{O}{||}}{C}-Cl\underset{sulphur}{\overset{Pd/BaS{O}_4}{\to }}C{H}_3-\underset{\underset{O}{||}}{C}-H+HCl$
(ii) $Methanal$ to $Ethanal$.
$Methanal$ reacts with $methylmagnesiumbromide$ followed by acid hydrolysis to form $ethanol$. Controlled oxidation gives $ethanal$