Preparation of 4-Acetamidobenzenesulfonamide

Ammonia is evolved in this procedure. If possible, perform this reaction in a hood. Otherwise, use an inverted funnel attached to a vacuum source (Fig. 2.71 b) to minimize escape of vapors of ammonia into the laboratory. 

Concentrated ammonium hydroxide is caustic and may cause burns if it is allowed to come in contact with your skin. Wear latex gloves when handling or transferring this reagent, and use care when working with it. Should any of the liquid come in contact with your skin, immediately flood the affected area with cold water. 

Preparation Sign in at www.cengage.com/login to answer Pre-Lab Exercises, access videos, and read the MSDSs for the chemicals used or produced in this procedure. Review Sections 2.9, 2.10, 2.11, and 2.17. 

Apparatus A 125-mL Erlenmeyer flask, ice-water bath, apparatus for vacuum filtration, and ffame/ess heating. 

Reaction, Work-Up, and Isolation Transfer the crude A-acetamidobenzenesulfonyl chloride obtained in the previous experiment to the Erlenmeyer flask, and add 15 mb of concentrated (28%) ammonium hydroxide. A rapid exothermic reaction may occur if the crude 4-acetamidobenzenesulfonyl chloride contains acidic contaminants that were not removed by the aqueous washings in the previous step. Use a stirring rod to break up any lumps of solid that may remain the reaction mixture should be thick but homogeneous. Heat the mixture at 70-80 C for about 0.5 h. Cool the reaction mixture in an ice-water bath and collect the product by vacuum filtration. Wash the crystals with cold water and air-dry them.  

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