Preparation of Acetanilide-I

The aim of this experiment is to prepare acetanilide. 

Here, acetanilide can be prepared by acetylation of aniline. Let us take a look at the preparation of acetanilide in a virtual lab.

Apparatus Required-

• Round bottom flask 
• Sand bath 
• Pumice stones 
• Buchner funnel
• Glass rod
• Water condenser
• Inlet for cold water
• Outlet for expelled water

Chemicals Required–

• Aniline 
• Acetic anhydride
• Glacial acetic acid

To prepare acetanilide, we have to follow the following procedure: 

• Take 5 mL of aniline in a 50 mL round bottom flask and add an acetylating mixture containing 5 mL acetic anhydride and 5 mL glacial acetic acid to it. 
• Alternatively, a mixture of 5 mL acetyl chloride and 5 mL dry pyridine can be used as the acetylating mixture.
• Then, fit a water condenser on the mouth of the round bottom flask after adding a few pumice stones and reflux the reaction mixture gently for about 10-15 minutes in a sand bath. 
• Cool the reaction mixture for a while. Now, pour it slowly into about 200 mL of ice-cold water while stirring. 
• The crude solid obtained during the preparation should be filtered and washed with cold water. 
• Recrystallise the pure acetanilide from hot water containing a few drops of methanol or ethanol.
• White, shining, needle-shaped crystals are obtained. Report the yield of the compound.

Precautions

• Handle acetic anhydride carefully, as it causes irritation to the eyes. 
• If you use acetyl chloride and pyridine, handle the reagents with extreme caution. Acetyl chloride fumes in the air strongly. 
• Store acetyl chloride under dry conditions. 
• Distil pyridine before use because it absorbs moisture, and the reaction does not take place under moist conditions. 
• Wash the solid 2-3 times with cold water till the filtrate is neutral to litmus.