432 I. K. and 21. A. Phelps — Preparation of Acetamide. 



could be recovered with a loss of less than 0-05 grm. The 

 acetamide tends to hold traces of water ; and it was not found 

 possible to remove it by fractional distillation in vacuo without 

 danger of loss of very small amounts of acetamide. 



The presence and amount of ammonium salt in the aceta- 

 mide obtained in the procedure outlined above were tested for 

 by the use of a solution of sodium cobalti-nitrite. An experi- 

 ment showed that 0*0002 grm. of ammonium chloride could be 

 readily detected in the presence of 0-50 gram of acetamide. The 

 acetamide obtained directly by fractioning in vacuo, as given 

 above, was found to contain traces of ammonia and ammonium 

 salt. In experiment (8) the erode material was transferred after 

 weighing the product obtained from the vacuum distillation to 

 a watchglass and allowed to stand in a desiccator over sulphu- 

 ric acid for twenty-four hours, and the loss sustained was 0'62 

 grm., presumably largely water with some ammonia. Some 

 of this loss must have been acetamide also, for by a separate 

 experiment with pure acetamide recrystallized from benzene 

 it was found that acetamide continually lost in weight in a 

 sulphuric acid desiccator. The acetamide from experiment (8) 

 after being dried showed the presence of not more than 0*30 

 grm. of ammonium salt, estimated by the amount of precipitate 

 produced with sodium cobalti-nitrite as compared with the 

 amount of precipitate obtained under similar conditions with 

 ammonium choricle, pure acetamide and sodium cobalti-nitrite. 

 The material obtained in experiment (22) was redistilled with 

 an air condenser under ordinary atmospheric pressure and 

 yielded 27*5 grm. of product boiling between 221° and 222°. 

 This product showed on testing with sodium cobalti-nitrite no 

 ammonium salt. Theoretically, more ammonium salt might 

 be present in those cases where the standing is longest. But 

 it was found on redistillation, under ordinary atmospheric 

 conditions, of the acetamide obtained directly by the processes 

 given above, that ammonium salt was not present in sufficiently 

 large amounts in the different experiments to be noticeable. 



It is clear from the work given that acetamide with only 

 traces of impurity may be obtained in quantities barely less 

 than quantitative for the amount of ethyl acetate taken, if 

 ethyl acetate and ammonium hydroxide are mixed in the 

 cold and allowed to stand a suitable length of time. Increas- 

 ing the amount of ammonium hydroxide employed shortens 

 the time of standing necessary for a theoretical yield, and 

 increasing the concentration of ammonia by saturating the 

 mixture of ethyl acetate and ammonium hydroxide in these 

 proportions with ammonia gas further diminishes, by one-half 

 or more, the time of standing. 



