Question

$R - \underset{\overset{||}{O}}{C} - Cl + H_2 \ce{->[Pd/BaSO_4][S]} RCHO$, the name of reaction is :

• A. Cannizaro reaction
• B. Rosenmund reduction
• C. Clemmensen reduction
• D. Wolff-Kishner reduction

Answer 1

Answer: (B)

Rosenmund reduction

Answer 2

Cannizaros reaction: The compound which does not contain $\alpha$ -hydrogen atom, undergoes self oxidation-reduction when reacted with $50\%$ aqueous or ethanolic alkali at room temperature.
$\underset{\text{formaldehyde}}{2HCHO} + H_2 \ce{->[Pd/BaSO_4]} \underset{\text{sod. formate}}{HCOONa} + \underset{\text{methanol}}{CH_3OH}$
Rosenmunds reduction: Acid chlorides when reduced by hydrogen in boiling xylene in presence of $Pd/BaS{{O}_{4}}$ ,
gives aldehyde in good yield.
$\underset{\text{acyl chloride}}{RCOCl} + H_2 \ce{->[Pd/BaSO_4]} \underset{\text{aidehyde}}{RCHO}$
Clenunensens reduction: It is commonly employed for reducing carbonyl group into methylene group.
Wolff-Kishner reduction: It is reduction of hydrazones, semicarbazones, or azines of aldehydes and ketones to hydrocarbons in vigorously basic conditions
$(C_{2}H_{5}ONa)$ or $NaOH$) with the evolution of nitrogen.
$\underset{\text{ketone}}{R_2C = O} + H_2NNH_2 \to \underset{\text{hydrazone}}{R_2C = N . NH_2}$