Question

Alkyl halide on heating with alc.NH\(_3\) in a sealed tube results ....

• A. 1° amine
• B. 2° amine
• C. 3° amine
• D. all of these

Hint:

Hoffmann's ammonolysis gives mixture of primary, secondary, tertiary amines.

Answer 1

The Correct Option is D

To solve this problem, we need to understand the reaction of alkyl halides with ammonia (NH₃) in alcohol, commonly referred to as alcoholic ammonia, in a sealed tube.

The reaction of alkyl halide with ammonia typically leads to the formation of amines through a series of substitution reactions. Here's how it proceeds:

1. Primary Amine Formation: Initially, the alkyl halide reacts with ammonia to form a primary amine. The reaction can be represented as: \(R-X + NH_3 \rightarrow R-NH_2 + HX\) where \(R-X\) is the alkyl halide and \(R-NH_2\) is the primary amine.
2. Secondary Amine Formation: The primary amine formed acts as a nucleophile and can further react with another molecule of alkyl halide to form a secondary amine: \(R-NH_2 + R-X \rightarrow R_2NH + HX\) where \(R_2NH\) is the secondary amine.
3. Tertiary Amine Formation: Similarly, the secondary amine can react with another molecule of alkyl halide to form a tertiary amine: \(R_2NH + R-X \rightarrow R_3N + HX\) where \(R_3N\) is the tertiary amine.
4. Quaternary Ammonium Salt Formation: Finally, the tertiary amine can react further to form a quaternary ammonium salt: \(R_3N + R-X \rightarrow R_4N^+X^−\)

In this sequence of reactions, primary, secondary, tertiary amines, and even quaternary ammonium salts can be formed depending on the reaction conditions and the availability of the alkyl halide.

Conclusion: Since all types of amines (1°, 2°, 3°) and even quaternary ammonium salts can be formed through consecutive reactions, the correct answer is "all of these". Thus, the primary outcome of heating an alkyl halide with alcoholic ammonia is not limited to just primary, secondary, or tertiary amines but can lead to the formation of all these products.