Acetamide [60-35-5-A] CH3CONH2
About the reaction: From lower carboxylic acids, the corresponding amide can generally be obtained by dry distillation of the ammonium salt of the carboxylic acid or, better, by heating the ammonium salt with an excess of the carboxylic acid at high temperature for a longer period and distilling off the water formed from the reaction mixture. The excess acid counteracts the dissociation of the ammonium salt into acid and ammonia.
Procedure: 80 g (1.0 mol) of ammonium acetate and 60 ml of glacial acetic acid (1.0 mol) are kept at gentle boiling on a wire gauze in a small round-bottom flask equipped with a Widmer or Vigreux column, thermometer, and descending condenser for 5-6 hours. Ensure that the temperature does not exceed 103 °C by much; the acetic acid and the water formed in the reaction distill off slowly and are collected for monitoring in a graduated cylinder. When about 80 ml has passed over, heat more strongly until the thermometer indicates 140 °C. Allow to cool slightly, pour the still warm melt into a 250-ml round-bottom flask, and distill fractionally under vacuum. (Caution! The distillate can solidify in the condenser). The main fraction passing over at 85-90 °C / 12 Torr solidifies upon cooling. Filter sharply on a Buchner funnel and dry the residue on clay in a non-evacuated desiccator. A further portion of acetamide can be distilled from the filtrate. The pure compound boils at 223 °C / 760 Torr; melting point at 80 °C. The yield is 55 g (over 90% of theory). The preparation can be used for the synthesis of acetonitrile.
Source: Gattermann, Ludwig - The Practice of Organic Chemistry, 43rd Edition, Walter de Gruyter, Berlin / New York 1982
Delivered by: Rhadon
Changed by: Mephisto
Last updated: 17/01/2006
Other name: Acetic acid amide