Experimental
Acetanilide: Measure 5.0 g of aniline into a 125-mL Erlenmeyer flask. Add 40 mL of water to the flask. Stir the contents while adding 6.5 mL of acetic
anhydride. After the addition, stir for an additional 10 min and then vacuum filter the product. Spread the solid out on a large piece of filter paper
in a petrie dish to dry quickly. Save a little for characterization and use the rest in the next step.
p-Nitroacetanilide: Add 3.0 g of acetanilide to 5 mL glacial acetic acid in a 25-mL Erlenmeyer flask. Carefully pour 5 mL concentrated sulfuric acid
into the mixture while stirring constantly. After the acetanilide has dissolved, place the flask in an ice-salt bath and cool it to 5 ºC. Prepare a
solution of 2 mL concentrated nitric acid and 1.3 mL concentrated sulfuric acid. While stirring the acetanilide solution, add dropwise the
nitric/sulfuric mixture at a rate such that the temperature does not rise over 20 ºC. After the addition, let the mixture stand at room temperature
for 20 min. Pour the reaction mixture into 25 mL of cold water with 15 g of ice. Collect the solid that forms by vacuum filtration and wash the solid
with three 30-mL portions of cold water. Recrystallize the solid from 95% ethanol and characterize it.
p-Nitroaniline: Add 2.2 g of p-nitroacetanilide and 5 mL of water to a 25 mL round bottom flask. Slowly add 5 mL concentrated sulfuric acid while
swirling. Reflux the mixture for 30 min. Cool the reaction mixture and pour the contents into a mixture of 15 g ice in 20 mL water. Slowly with
stirring add 9 M sodium hydroxide until the pH of the mixture reaches 4-5. Cool the mixture in an ice bath and collect the precipitate by vacuum
filtration. Wash the solid four times with 20 mL portions of water. Characterize the p-nitroaniline. |