Final answer:
To identify if an amine is primary, secondary, or tertiary, use the Hinsberg test which involves reacting the amine with benzene sulfonyl chloride. Primary amines form soluble sulfonamides, secondary amines form insoluble sulfonamides, and tertiary amines do not react.
Step-by-step explanation:
To identify primary, secondary, and tertiary amines, you can perform a chemical test called the Hinsberg test. This test distinguishes between the three types of amines by their ability to form soluble or insoluble salts upon reaction with benzene sulfonyl chloride (Hinsberg’s reagent).
- Primary amines react with Hinsberg’s reagent to form a sulfonamide that is soluble in an alkali solution due to the presence of an acidic hydrogen atom that can be removed to form a salt.
- Secondary amines also react to form a sulfonamide, but since there are no hydrogen atoms attached to the nitrogen after the reaction, the product is insoluble in alkali.
- Tertiary amines do not react with Hinsberg’s reagent because there is no hydrogen atom available to form the sulfonamide.
Chemical equations representing these reactions are as follows:
- Primary amine: RNH2 + C6H5SO2Cl → RNH-SO2C6H5 + HCl
- Secondary amine: R2NH + C6H5SO2Cl → R2N-SO2C6H5 + HCl
- Tertiary amine: R3N + C6H5SO2Cl → no reaction