4-Acetamidobenzenesulfonyl chloride preparation

In this experiment, you will prepare the sulfa drug sulfanilamide by the following synthetic scheme. The synthesis involves converting acetanilide to the intermediate p-acetamidobenzenesulfonyl chloride in Step 1. This intermediate is converted to sulfanilamide by way of p-acetamidobenzenesulfonamide in Step 2. 

Chlorosulfonic acid must be handled with care because it is a corrosive liquid and reacts violently with water. The p-acetamidobenzenesulfonyl chloride should be used during the same laboratory period in which it is prepared. It is unstable and will not survive long storage. The sulfa drug may be tested on several kinds of bacteria (Instructor s Manual). 

Prepare a hot water bath at 70°C. Place the crude p-acetamidobenzenesulfonyl chloride into the original 5-mL conical vial and add 1.1 mL of dilute ammonium hydroxide solution. Stir the mixture well with a spatula and reattach the air condenser and drying tube (gas trap) using fresh, moistened glass wool. Heat the mixture in the hot water bath for 10 minutes. Allow the conical vial to cool to the touch and place it in an ice-water bath for several minutes. Collect the p-acetamidoben-zenesulfonamide on a Hirsch funnel and rinse the vial and product with a small amount of ice water. You may stop here. 

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