Hinsberg test for amines

BenzenesuKonyl chloride is a lachrymator and produces strong acids upon hydrolysis. Wear latex gloves when handling this reagent, measure it out in a hood, and avoid inhaling its vapors. Should this reagent come in contact with your skin, immediately flood the area with water and rinse it with 5% sodium bicarbonate solution. 

Preparation Sign in at www.cengage.com/login to read the MSDSs for the chemicals used or produced in this procedure. 

Mix 5 mL of 2 /W aqueous potassium hydroxide. 0.2 mL (5 drops) or 0.2 g of the amine, and 0.7 mL (15 drops) of benzenesulfonyl chloride in a test tube. Stopper the tube and shake the mixture vigorously, with cooling if necessary, until the odor of benzenesulfonyl chloride is gone (Caution ). In even the slowest case, this should take no more than about 5 min. Test the solution to see that the mixture is still basic if it is not, add sufficient 2 potassium hydroxide solution dropwise until it is. 

If the mixture forms two layers or a precipitate, note the relative densities, and separate the oil or solid by decantation or filtration. Test any oil for solubility in 0.6 M 

Test any solid for solubility in water and in dilute acid. The potassium salt of a water-insoluble sulfonamide is usually soluble in water acidifying the salt regenerates the sulfonamide, which is insoluble in aqueous acid. A solid sulfonamide of a secondary amine is insoluble in both water and acid. Acidify the solution from the original reaction mixture to pH 4 as signaled by pHydrion paper or a few drops of Congo red indicator solution the formation of a precipitate or oil indicates a primary amine. 

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