Question

Which catalyst is used in the Rosenmund Reduction?

• A. Pd–BaSO$_4$
• B. Ni catalyst
• C. Pt catalyst
• D. Cu catalyst

Hint:

Rosenmund Reduction:
Acid Chloride \(\rightarrow\) Aldehyde using \(Pd-BaSO_4\).

Answer 1

The Correct Option is A

Concept:
Rosenmund Reduction is an important organic reaction used to convert acid chlorides into aldehydes. The reaction involves hydrogenation of acid chlorides in the presence of a specially poisoned palladium catalyst.

Step 1: Understanding the reaction
\[ RCOCl + H_2 \rightarrow RCHO + HCl \] In this reaction, the acid chloride is reduced to an aldehyde.

Step 2: Role of the catalyst
The catalyst used is palladium deposited on barium sulfate (\(Pd-BaSO_4\)). The catalyst is often “poisoned” with substances such as sulfur or quinoline to prevent further reduction of the aldehyde to alcohol.

Step 3: Importance of poisoning
Without poisoning, the aldehyde formed could be further reduced to a primary alcohol. The poisoned catalyst ensures the reaction stops at the aldehyde stage. Conclusion:
Thus, the catalyst used in Rosenmund Reduction is Pd–BaSO$_4$, commonly known as the Rosenmund catalyst.