430 1. K. and M. A. Phelps— Preparation of Acetamide. 



above. In every case, after the solution had stood a sufficient 

 time in the reagent bottle stoppered tightly so that the ammo- 

 nia gas should not escape, it was transferred to a 250 cma distil- 

 ling flask, connected with a 100 om3 distilling flask in the usual 

 way for a vacuum distillation, with the use of the least amount 

 of absolute alcohol to rinse the sides of the bottle. The low 

 boiling impurities, ammonia, alcohol, and water, were removed 

 by fractioning in vacuo in the usual way, the 250 cm3 flask being- 

 heated in a bath of hot water finally at 60° for fifteen min- 

 utes after the pressure on the manometer registered 15 mm . 

 The acetamide left in the flask was distilled by heating the 

 flask in an acid potassium sulphate bath at 140° to 150°, and 

 was collected in the receiver, cooled by a stream of cold water, 

 and weighed. 



The experiments of section A are those in which the pure 

 ammonium hydroxide of commerce was used with the ethyl 

 acetate, and after standing suitably the mixtures were distilled 

 in vacuo as given above. 



The experiments of section B were conducted in the same 

 way as those in section A, except that the ammonium hydrox- 

 ide used was saturated at —10° with dry ammonia before 

 mixing in the cold with the ethyl acetate. 



The experiments of section C were conducted in the same 

 way as those of A excepting that the entire mass of ethyl ace- 

 tate and ammonium hydroxide after mixing in the cold was 

 saturated with dry ammonia gas at — 8° to —10°. 



From an inspection of the results recorded in section A it is 

 seen that the volume of ammonium hydroxide taken for a given 

 weight of ethyl acetate, as well as the time allowed for the 

 interaction of the ethyl acetate and ammonia, influences the 

 yield of acetamide. The theoretical yield can be obtained 

 with tiie proportion and concentration of the reagents used 

 here only on long standing. Two weeks' standing at ordinary 

 temperatures with so large an amount as *J5 cm3 f the ammo- 

 nium hydroxide for 50 grm. of ethyl acetate will give the 

 yield required by theory, although for smaller proportions of 

 the ammonium hydroxide that time is not sufficient. 



It is evident from the results given in section B that a solu- 

 tion of saturated aqueous ammonia tends to give a larger yield 

 of acetamide in a given time than can be obtained by weaker 

 aqueous ammonia. 



In section C the results show that in shorter time than by 

 the procedure in experiments given in A and B of the table 

 the theoretical yield of acetamide may be obtained by satura- 

 ting in the cold the mixture of ethyl acetate and ammonium 

 hydroxide and allowing it to stand either four or six days 

 according to the proportion of the aqueous ammonia present. 



