174: Phelps and Deming — Preparation of Formamide. 



In certain experiments the ethyl formate and ammonium 

 hydroxide were mixed in a 250 om3 distilling flask and the mix- 

 ture was fractioned in vacuo as soon as it had become homo- 

 geneous. In this process the 250 cm3 distilling flask containing 

 th<* mixture was connected to a 100 cm3 distilling flask used as a 

 ..er and the formamide was separated from low-boiling 

 „ purities by fractioning in vacuo in the usual way, the distilling 

 flask being heated in a water bath at 60° for fifteen minutes 

 after the pressure on the manometer registered 15 mm . The 

 formamide was then distilled over, by heating the distilling 

 flask in a bath of sulphuric acid and potassium sulphate,* and 

 caught in the receiver chilled by a current of cold water. 



In other experiments the distillation was not made as soon 

 as the ethyl formate and ammonium hydroxide had become 

 homogeneous. In each of these experiments a definite weight 

 of ethyl formate held in a 250 cm3 glass-stoppered reagent bottle 

 was treated with pure, commercial ammonium hydroxide of 

 known strength, after chilling each in a mixture of ice and 

 salt, slowly enough so that at no time during mixing did 

 the temperature of the mixture rise above 0°. The mix- 

 ture at this time consisting of two layers became homogeneous 

 in about five minutes, but was allowed to stand in the ice mix- 

 ture for fifteen minutes ; for the heat given out showed that 

 the reaction progressed after the mass had become homogene- 

 ous. This solution was kept tightly stoppered for a definite 





Ethyl 



fnvm sip 



Ammonium 



hydroxide 



Sp. gr. -90 



cm 3 . 



Time of standing 



Formamide 





Theory 

 grm. 



Found 



No. 



grm. 



hr. 



min. 



grm. 



(0 



50 



30 



A 

 4 



30 



30-41 



19-06 



(2) 



50 



30 



240 





30'41 



23-40 



(3) 



50 



50 







30-41 



23-57 



(4) 



• 50 



50 







30-41 



22-60 



(5) 



50 



50 



1 





30-41 



28-08 



(6) 



50 



50 



1 





30-41 



27-40 



(<) 



50 



• 50 



2 





30-41 



29-33 



(8) 



50 



50 



2 





30-41 



29-78 



(9) 



50 



50 



2 





30-41 



29-80 



(10) 



50 



50 



5 





30-41 



30-48 



(11) 



50 



50 



5 





30-41 



30-45 



(12) 



50 



50 



6 



30 



30-41 



30-50 





Treatment 



with NH 4 OH and saturation of mixture with NH 3 





(13) 



50 



10 



4 





30-41 



30-45 



(14) 



50 



10 



4 





30-41 



30-00 



(15) 



50 



20 



4 





30-41 



30-25 



time, after which it was transferred to a 250 cm3 distilling flask 



connected to a 100 cm3 distilling flask used as a receiver with the 



*H. Scudder, Jour. Am. Chern. Soc, xxv, 161. 



