Question

Aniline in a set of reactions yielded a product D?

The product D is:
A.\[{C_6}{H_5}NHOH\]
B.\[{C_6}{H_5}NHC{H_2}C{H_3}\]
C.\[{C_6}{H_5}C{H_2}N{H_2}\]
D.\[{C_6}{H_5}C{H_2}OH\]

Answer 1

Hint: Aniline is an aromatic amine having a primary aromatic amine functional group. The reaction here is an example of a coupling reaction where carbon couples with carbon to form a C-C single bond.

Complete Step by Step Solution:
In the first step, \[\left( {NaN{O_2} + HCl} \right)\]reacts with each other to form nitrous acid\[\left( {HONO} \right)\], which reacts with aniline to give a diazotization reaction and form benzene diazonium chloride salt product (A). This product (A) further reacts with copper cyanide \[\left( {CuCN} \right)\]to give a Sandmayer’s reaction and forms cyano benzene or benzonitrile product (B). Then product (B) reacts with hydrogen gas in presence of nickel catalyst to give benzylamine (C) by reduction, which further reacts with nitrous acid \[\left( {HONO} \right)\]which is an oxidising agent and forms benzyl alcohol, the final product (D). The reaction mechanism is shown below:

Image:Reaction with aniline to give benzyl alcohol

So, option D is correct.

Additional Information:Aromatic diazonium chloride salts formed by the reaction of aniline and nitrous acid are electrophiles and undergo electrophilic substitution reaction i.e., electron-loving compounds attack them. In this way, it works in coupling reactions.
In the reaction of copper cyanide with aromatic diazonium chloride salt, partial positive charges on Cu forms a bond with negative charges on chloride ion of salts and form \[CuCl\]and \[{N_2}\]releases as nitrogen gas and partial negative charges on cyanide attack the aromatic ring to form cyanobenzene.

Note: Anilines are also known as phenyl benzene or aminobenzene. Nitrous acid is a weak acid used in the preparation of diazonium salts. The reaction asked in this question is an azo coupling reaction used to form C-C bonds.