Phelps and Deming — Preparation of Formamide. 175 



use of the least amount of alcohol to remove the last traces 

 from the side-walls of the bottle. The formamide was separated 

 from low-boiling impurities by fractioning in vacuo in the 

 manner described, and the formamide distilled and weighed. 



It is obvious from the work recorded in the table that Lhfiree 

 factors are of influence in the quantitative formation of 10. 

 mide by the interaction in the cold of ethyl formate a., a 

 ammonium hydroxide, — the excess of the ammonium hydroxide 

 present, the concentration of the ammonia in the solution, and 

 the time during which the interaction of the two is allowed, 

 From experiments (1) and (2) of section A of the table it is 

 clear that w T ith fixed amounts of ethyl formate and ammonium 

 hydroxide an increase in the length of the time of the reaction 

 is decidedly advantageous. The comparison of experiments (1) 

 and (2) with experiments (5) to (12) shows that increasing the 

 amount of ammonium hydroxide gives a yield in excess of that 

 found w T ith the smaller proportion of ammonium hydroxide. 

 A comparison of experiments (5) to (12) with dne another fur- 

 ther emphasizes the point that length of time allowed for the 

 completion of the reaction after the mixture has been kept cool 

 during the first of the reaction long enough to prevent hydra- 

 tion is an important factor. It is clear that it is easily possible 

 to obtain the theoretical amount of amide by allowing the 

 mixture to stand five hours or longer. Two hours standing is 

 not quite sufficient. 



In section B of the table the results shown were obtained by 

 saturating in the cold, at —10° to 0° for about four hours, the 

 ethyl formate and ammonium hydroxide chilled before mixing 

 in a stoppered reagent bottle fitted with a rubber stopper 

 carrying in one perforation a thermometer dipping into the 

 mixture and in the other the delivery tube for the ammonia gas. 

 This mixture on fractioning in vacuo as described above and 

 distilling the formamide left in the distilling flask gave the 

 theoretical amount of formamide. 



An experiment showed that a definite weight of formamide 

 and water when fractioned in vacuo as in the process outlined 

 gave an amount of formamide differing from that taken by less 

 than 0'05 grm. 



It is evident that it is "possible to obtain from ethyl formate 

 by the action of ammonium hydroxide the theoretical amount 

 of formamide. This may be accomplished by treating the chilled 

 ethyl formate with small amounts of chilled ammonium 

 hydroxide and saturating for some hours in the cold with dry 

 ammonia gas; or, more easily, by treating chilled ethyl formate 

 with larger proportions of chilled ammonium hydroxide and 

 allowing the mixture to stand some hours before distilling in 

 vacuo. The essential thing in the operation is to keep the 

 mixture of the ethyl formate and the ammonium hydroxide at 

 a temperature so low that ammonium formate is not a product 

 of the action. 



