Preparation of Amines

Preparation of Amines: Reduction, replacement, or rearrangement reactions may be used to get aliphatic amines.

(A) Aliphatic amines are prepared by the reaction between either alcohol or an alkyl halide and ammonia.

Preparation of Amines

Copper chromite or alumina (Al2O3) may be used as a catalyst. Using a large excess of ammonia, the yield of primary amine may be increased.

Preparation of Amines

The order of reactivity of alkyl halide is

alkyl iodide > alkyl bromide > alkyl chloride

(B) Similarly by the reduction of a nitroalkane, an amine is obtained. Metal and acid or catalytic reduction may be used for this purpose.

Hafmann rearrangement

It is a commonly used method for the preparation of primary amines. One of the commonly used rearrangement reactions to get amine is Hofmann degradation or Hafmann rearrangement.

(C) Hofmann degradation may be represented by the following reaction.

Hafmann rearrangement

(D) Primary, secondary or tertiary amides may be reduced to corresponding amines by refluxing with diborane in tetrahydrofuran.


(E) Aldehyde or ketone may be converted to the corresponding amine by treatment with an excess of ammonia and hydrogen under pressure over Raney nickel at 60° – 150°C.


Alternatively, excess ammonium chloride and  H2 over platinum catalyst may be used. Such a type of reaction is known as reductive alkylation.

(F) Primary amines may be obtained by reduction of alkyl cyanides or oximes.

Primary amines

(G) Miscellaneous methods of preparation of amines :

(i) Curtius reactions :

Curtius reactions

(ii) Lossen rearrangement:

Lossen rearrangement

(iii) Wurtz reaction:

Wurtz reaction

(iv) Leuckart reaction:

Leuckart reaction

(v) Schmidt reaction:

Schmidt reaction

(vi) Grignard reaction:

Grignard reaction

(vii) Gabriel’s phthalimide synthesis:

Gabriel's phthalimide synthesis

(viii) Henze reaction (for secondary and tertiary amine):

Preparation of Amines

(ix) Decarboxylation of amino acids:

Decarboxylation of amino acids

The preparation of aromatic amines does not differ principally from the methods used for aliphatic amines. For example, the reduction of a nitro compound may be carried out either by catalytic hydrogenation or by the reagents like iron and a dilute HCI.

Preparation of Amines

Similarly, a chloro compound or phenol may be treated with ammonia (i.e. ammonolysis) at high temperature and high pressure in the presence of a catalyst to get aromatic amine.

aromatic amine

Hofmann rearrangement and many other rearrangement reactions specified in the preparation of aliphatic amines are equally applicable in the preparation of aromatic amines.

Make sure you also check our other amazing Article on : Structure and Uses of Phenol
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