Question

The major product of the following chemical reaction is : R-CN $\xrightarrow{(1) H_3O^+, \Delta (2) SOCl_2 (3) Pd/BaSO_4, H_2}$ ? (Using $R$ as the alkyl group from the prompt skeleton)

• A. Alcohol
• B. Anhydride
• C. Alkane
• D. Aldehyde

Hint:

Rosenmund Reduction ($Pd/BaSO_4$ with $S$ or quinoline) is a poisoned catalyst method that stops the reduction of acid chlorides at the aldehyde stage, preventing further reduction to alcohol.

Answer 1

The Correct Option is D

Step 1: $R-CN \xrightarrow{H_3O^+, \Delta} R-COOH$ (Complete hydrolysis of Nitrile to Carboxylic Acid).
Step 2: $R-COOH \xrightarrow{SOCl_2} R-COCl$ (Formation of Acid Chloride).
Step 3: $R-COCl \xrightarrow{H_2, Pd/BaSO_4}$ is the Rosenmund Reduction.
Step 4: The acid chloride is reduced specifically to an aldehyde.