Question

Methylamine can be prepared by:
A. Wurtz reaction
B. Friedel-Crafts reaction
C. Hofmann’s bromamide reaction
D. Clemmensen’s reaction

Answer 1

Hint: As we know that Methylamine can be prepared by the reaction in which we get one less carbon atom in the product than that of the reactant or we can say in which degradation of carbon takes place.

Complete answer:
- As we know that in Hofmann’s bromamide reaction, an amide reacts with an aqueous solution of sodium hydroxide and bromine that produces primary amine.
- It is found that this reaction is called a degradation reaction as the product of this reaction is a primary amine with one carbon atom less than that of the primary amide.
- In words we can write the as:
Primary amide + $B{{r}_{2}}$+ NaOH $\to$Primary amine
- We can prepare Methylamine by Hofmann’s bromamide reaction. We can see the reaction that takes place as:
\[C{{H}_{3}}-CO-N{{H}_{2}}+B{{r}_{2}}+4NaOH\to C{{H}_{3}}-N{{H}_{2}}+N{{a}_{2}}C{{O}_{3}}+2NaBr+2{{H}_{2}}O\]

- Hence, we can conclude that the correct option is (c), that is Methylamine can be prepared by Hofmann’s bromamide reaction.

Additional information:
- There are many applications of Hofmann’s bromamide reaction like: it is also used to produce aniline, used in the preparation of phthalimide, 3-aminopyridine and anthranilic acid.
- It is found that Hofmann’s bromamide reaction doesn’t change the symmetrical structure of phenyl propanamide.

Note: - It is to be noted that there is a limitation of Hofmann’s bromamide reaction, that secondary and tertiary amides cannot be used to produce primary amines.