Ch 30 Amines - Core Points

EE Syllabus

Amines:
Preparation, Properties, Reactions
Characteristic reactions
Basicity of substituted anilines and aliphatic amines,
Preparation from nitro compounds,
Reaction with nitrous acid,
Azo coupling reaction of diazonium salts of aromatic amines,
Sandmeyer and related reactions of diazonium salts;
Carbylamine reaction;


Amines are regarded as derivatives of ammonia in which one, two or all three hydrogen atoms are replaced by alkyl or aryl group.

Preparation from nitro compounds,

Reduction of nitro compound to obtain amine can be done by using either molecular hydrogen and a catalyst (Ni or Pt) or a metal (usually granulated tin) and an acid (HCl)

Reaction with nitrous acid,
Aliphatic primary amine in reactin with nitrous acid forms unstable diazonium salt which on decomposing liberates nitrogen and mixture of alcohols and alkenes.

Basicity of substituted anilines and aliphatic amines,
Nitrogen of amines contains lone pair of electrons, which can be shared with other species and thus these act as Lewis bases.

Azo coupling reaction of diazonium salts of aromatic amines,

Sandmeyer and related reactions of diazonium salts;
The diazonium salt is treated with cuprous chloride or cuprous bromide.

Carbylamine reaction;
The treatment of a primary amine with chloroform and alcoholic potash produces carbylamine (isocyanide) which has most offensive smell. This reaction is not exhibited by secondary and tertiary amines.