2.8: The preparation of Acetanilide from Aniline
- Page ID
- 494264
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Safety Features
- Aniline is toxic and can be absorbed through the skin. Use in a fume hood.
- Concentrated hydrochloric acid can cause severe burns.
- Acetic anhydride is lachrymatory.
Procedure
To 60 mL water in a 100 mL Erlenmeyer flask add 2 mL concentrated hydrochloric acid with mixing.
The next step must be done in the fume hood.
Add 2 mL aniline (density 1.02 g cm-3) and swirl the mixture.
If the solution is coloured, add a small amount of decolourising charcoal, swirl the flask for about one minute, and filter off the carbon using a fluted filter paper (see the Appendix).
In a separate container dissolve 3 g sodium acetate in 10 mL water.
Warm the anilinium chloride solution to 50°C on a water bath and add 3 mL acetic anhydride (density 1.08 g cm-3).
Swirl to effect dissolution and add the aqueous sodium acetate quickly. Swirl the flask a couple of times and set it in an ice-bath for 20 min.
Filter, with suction, the crystals of the amide formed and wash with a small amount of ice-cold water. Continue to apply suction to the Büchner funnel for a few minutes.
Dry the material between filter papers and submit your sample for assessment.
Determine the yield and melting point of your product.
Inspect the I.R. spectra of aniline (starting material) and acetanilide (product) and record on your worksheet the position of the major bands that differ between the two (see Appendix 3). Relate this data to the reaction that has occurred.
Carry out the nitrous acid test on the 1° aliphatic amine and the on the 1°, 2° and 3° aromatic amines provided. Record your results in tabular form.