Differentiate between primary, secondary, and tertiary amines using the Hinsberg test. Explain the chemical reactions involved with equations.

Q: Differentiate between primary, secondary, and tertiary amines using the Hinsberg test. Explain the chemical reactions involved with equations.

Introduction to Hinsberg Test\nBenzene sulphonyl chloride ($C6H5SO2Cl$), also known as Hinsberg's reagent, reacts with primary, secondary, and tertiary amines to yield products with distinct solubility properties in alkali. This reaction is widely used in the laboratory to distinguish between the three classes of amines. Reaction with Primary Amines\nPrimary amines react with benzene sulphonyl chloride to form N-alkylbenzene sulphonamide. $$C6H5SO2Cl + H2N-R \rightarrow C6H5SO2NH-R + HCl$$\nThe hydrogen attached to nitrogen in this sulphonamide is strongly acidic due to the electron-withdrawing effect of the sulphonyl group. Therefore, this N-alkylbenzene sulphonamide dissolves in aqueous alkali (such as $NaOH$) to form a clear soluble salt. $$C6H5SO2NH-R + NaOH \rightarrow C6H5SO2N^-RNa^+ + H2O$$ Reaction with Secondary Amines\nSecondary amines react with benzene sulphonyl chloride to form N,N-dialkylbenzene sulphonamide. $$C6H5SO2Cl + HN(R)2 \rightarrow C6H5SO2N(R)2 + HCl$$\nIn this case, the resulting sulphonamide does not contain any hydrogen atom attached to the nitrogen atom. Consequently, it is strongly acidic-free and insoluble in aqueous alkali ($NaOH$). Reaction with Tertiary Amines\nTertiary amines do not possess any replaceable hydrogen atom on the nitrogen atom and therefore do not react with benzene sulphonyl chloride at all. However, they may dissolve in dilute mineral acids due to salt formation. Summary of Identification Primary amine: Reacts to form a sulphonamide that is soluble in alkali. Secondary amine: Reacts to form a sulphonamide that is insoluble in alkali. Tertiary amine: Does not react with Hinsberg's reagent.

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Introduction to Hinsberg Test
Benzene sulphonyl chloride ($C6H5SO2Cl$), also known as Hinsberg's reagent, reacts with primary, secondary, and tertiary amines to yield products with distinct solubility properties in alkali. This reaction is widely used in the laboratory to distinguish between the three classes of amines. Reaction with Primary Amines
Primary amines react with benzene sulphonyl chloride to form N-alkylbenzene sulphonamide. $$C6H5SO2Cl + H2N-R ightarrow C6H5SO2NH-R + HCl$$
The hydrogen attached to nitrogen in this sulphonamide is strongly acidic due to the electron-withdrawing effect of the sulphonyl group. Therefore, this N-alkylbenzene sulphonamide dissolves in aqueous alkali (such as $NaOH$) to form a clear soluble salt. $$C6H5SO2NH-R + NaOH ightarrow C6H5SO2N^-RNa^+ + H2O$$ Reaction with Secondary Amines
Secondary amines react with benzene sulphonyl chloride to form N,N-dialkylbenzene sulphonamide. $$C6H5SO2Cl + HN(R)2 ightarrow C6H5SO2N(R)2 + HCl$$
In this case, the resulting sulphonamide does not contain any hydrogen atom attached to the nitrogen atom. Consequently, it is strongly acidic-free and insoluble in aqueous alkali ($NaOH$). Reaction with Tertiary Amines
Tertiary amines do not possess any replaceable hydrogen atom on the nitrogen atom and therefore do not react with benzene sulphonyl chloride at all. However, they may dissolve in dilute mineral acids due to salt formation. Summary of Identification Primary amine: Reacts to form a sulphonamide that is soluble in alkali. Secondary amine: Reacts to form a sulphonamide that is insoluble in alkali. Tertiary amine: Does not react with Hinsberg's reagent.

NCERT · Class 12 · Chemistry · AminesDifferentiate between primary, secondary, and tertiary amines using the Hinsberg test. Explain the chemical reactions involved with equations.

Reaction with Primary Amines\nPrimary amines react with benzene sulphonyl chloride to form N-alkylbenzene sulphonamide.

Reaction with Secondary Amines\nSecondary amines react with benzene sulphonyl chloride to form N,N-dialkylbenzene sulphonamide.

Reaction with Tertiary Amines\nTertiary amines do not possess any replaceable hydrogen atom on the nitrogen atom and therefore do not react with benzene sulphonyl chloride at all. However, they may dissolve in dilute mineral acids due to salt formation.

Summary of Identification