Hinsberg reaction
Encyclopedia
The Hinsberg reaction is a chemical test
Chemical test
In chemistry, a chemical test is a qualitative or quantitative procedure designed to prove the existence of, or to quantify, a chemical compound or chemical group with the aid of a specific reagent...

 for the detection of amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...

s.It is an excellent test for distinguishing primary,secondary and tertiary amines.In this test, the amine is shaken well with Hinsberg reagent in the presence of aqueous alkali (either KOH or NaOH). A reagent containing an aqueous sodium hydroxide solution and benzenesulfonyl chloride is added to a substrate. A primary amine will form a soluble sulfonamide
Sulfonamide (chemistry)
In chemistry, the sulfonamide functional group is -S2-NH2, a sulfonyl group connected to an amine group.A sulfonamide is a compound that contains this group. The general formula is RSO2NH2, where R is some organic group. For example, "methanesulfonamide" is CH3SO2NH2...

 salt which precipitates
Precipitation (chemistry)
Precipitation is the formation of a solid in a solution or inside anothersolid during a chemical reaction or by diffusion in a solid. When the reaction occurs in a liquid, the solid formed is called the precipitate, or when compacted by a centrifuge, a pellet. The liquid remaining above the solid...

 after addition of diluted hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....

. A secondary amine in the same reaction will directly form an insoluble sulfonamide. A tertiary amine will not react with the sulfonamide but is insoluble. After adding dilute acid this insoluble amine is converted to a soluble ammonium salt. In this way the reaction can distinguish between the three types of amine.

The Hinsberg reaction was first described by Oscar Hinsberg in 1890 .

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