Procedure

Acetylation

1. Dissolve 3.7 g (3.6 mL) of aniline in 100 mL of 0.4 N hydrochloric acid in a 250-mL Erlenmeyer flask containing a stirbar.

2. Stir to dissolve.

3. Warm the solution to 50 ºC on a hot plate with swirling and transfer the flask to a magnetic stirrer.

4. Prepare a solution containing 6.0 g of sodium acetate trihydrate dissolved in 20 mL of water. In a separate container, measure out 4.4 mL of acetic anhydride.

5. Add the acetic anhydride in one portion to the solution of anilinium hydrochloride.

6. Stir the solution vigorously.

7. Add the solution of sodium acetate immediately and in one portion.

8. Cool the mixture to 5 ºC in an ice-water bath.

9. Continue to sitr until the crystalline product completely precipitates.

10. Collect the acetanilide by vacuum filtration.

11. Wash it with a small portion of ice-cold water.

12. Air-dry it.

13. Add 2 mL of acetic anhydride to the filtrate, swirl to dissolve the anhydride, and cool the flask in ice.

14. Additional acetanilide may precipitate; collect the solid by vacuum filtration, wash it with a small amount of cold water, and combine it with the first crop.

15. Save a small sample. Determine the melting point.

16. Use the sample directly as the starting material for the bromination.

Bromination

1. Solvent: 5 mL of acetic acid for every 0.01 mole of acetanilide

2. Concentration: 0.010 moles of bromine per 1.0 mL of solution

3. Prepare a solution of bromine in glacial acetic acid in an Erlenmeyer flask with a stirbar.

4. Add the bromine solution to the rapidly stirred solution of acetanilide over a period of 1-2 min; continue stirring the mixture for 10 min.

5. Slowly add 100 mL of ice-cold water with stirring and then add enough ice-cold saturated aqueous sodium bisulfate to discharge the color of the mixture that results.

6. Cool the mixture in an ice-water bath and collect the product by vacuum...