When a primary amine reacts with \(CHCl_3\) in presence of ethanolic \(KOH\) to produce a foul smelling compound, the reaction is called:

Carbylamine test

The correct answer is option 4. Carbylamine test.

Carbylamine reaction mechanism includes the addition of amine to the intermediate created from the dehydrohalogenation of chloroform. This intermediate is called dichlorocarbene. The carbylamine reaction is also known as Hofmann isocyanide synthesis. It is the reaction of a primary amine, chloroform and a base to synthesize isocyanides. The dichlorocarbene intermediate is very important for this conversion. The carbylamine reaction cannot be used to synthesize isocyanides from secondary or tertiary amines. In general, the carbylamine reaction can be written as –

\(R-NH_2 + CHCl_3 + 3KOH \longrightarrow RNC + 3KCl + 3H_2O\)

Here are a few examples of the carbylamine reaction.

Example:

The reaction mechanism of carbylamine reaction is as follows. The reaction mechanism includes the reaction of a primary amine to the intermediate (dichloroCarbene) formed from the dehydrohalogenation of chloroform. This intermediate is called dichlorocarbene. The heat in the reaction is required to generate the dichlorocarbene from chloroform.