Identification of Primary Amines, Secondary Amines and Tertiary Amines

When an organic compound with one or more hydrogen atoms of the ammonia molecule is replaced with an alkyl or even an aryl group, these compounds are classified as amines, These are carbon atoms which are bonded to the nitrogen atom and their bond is quite strong. Amines are similarly divided into 3 different types; which are:

  1. Primary amine
  2. Secondary amine
  3. Tertiary amine

Once it bonds with 2 carbon atoms it is called as a secondary amine and when it bonds with 3, it is called as a tertiary amine. Primary, Secondary and Tertiary amines all show different chemical properties and also have physical, observable changes. They are mainly used in industrial and commercial applications.

Amines usually have particularly distinct properties about them, such as odors, these odors usually that of rotting eggs or fishes. Aliphatic amines are amines that are less dense than water and are usually stronger bonds of ammonia than aromatic amines. The major industrial applications are in making rubber, dyes, pharmaceuticals and synthetic resins and fibers. Certain tests are carried out for the identification of primary amines, secondary amines, and tertiary amines. One of the most popular tests is Hinsberg test and the reaction produced from this test is called the Hinsberg reaction.

Hinsberg test

A chemical test that is most commonly used for the identification of primary, secondary and tertiary amines is called the Hinsberg test. An amine in the presence of an aqueous alkali interacts with a Hinsberg reagent. Thus, this is what is meant as the Hinsberg test. After the reaction, the following observations are observed:

Getting a primary amine to react with a Hinsberg reagent usually leads to an amide being formed, called as N-ethylbenzenesulphonyl amide, whereas the reagent used is called benzenesulfonyl chloride. This is strongly acidic as the hydrogen that is attached as a part of the nitrogen compound. Thus, this solution is also soluble in alkali.

 Identification of Primary Amines
 Identification of Primary Amines

Thus, Hinsberg test is effective for the identification of primary amines, secondary amines, and tertiary amines. Amines are usually used for a variety of different purposes such as a variety of different medicines and photographs. Apart from this, the amine is also used for the synthesis of rocket propellants and insecticides. Thus, amines have a whole host of different uses in the industry along with their traditional chemical uses. It is also used in heavy-duty military functions such as the creation of synthetic fibers, used in the production of Kevlar, which is the key component in creating helmets and bulletproof vests for protection of soldiers in warfare.

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