E Preparation of Sulfanilamide

Concentrated hydrochloric acid is corrosive and may cause serious 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 acid come in contact with your skin, immediately i ood the affected area with cold water and then rinse it with 5% sodium bicarbonate solution. 

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. 2.17. and 2.22. 

Apparatus A 50-mL round-bottom flask, ice-water bath, apparatus for heating under reflux, magnetic stirring, vacuum filtration, and flameless heating. 

Setting Up Prepare 20 mL of a solution of dilute hydrochloric acid by adding 10 mL of concenfrafed hydrochloric acid to 10 mL of water swirl to mix. Equip the round-bottom flask with a stirbar and add the 4-acetamidobenzenesulfonamide and an amount of dilute hydrochloric acid that is about twice the weight of the crude 4-acetamidobenzenesulfonamide. Assemble the apparatus for heating under reflux. 

Reaction, Work-Up, and Isolation Heat the reaction mixture with stirring under gentle reflux for 45 min and then allow the mixture to cool to room temperature. If any solid, which is unreacted starting material, appears on cooling, reheat the mixture under reflux for an additional 15 min. Add an equal volume of water to the cooled solution and transfer the resulting mixture to a beaker. Neutralize the excess hydrochloric acid by adding small quantities of solid sodium carbonate until the solution is slightly alkaline. 

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