Phelps and Ueming — Preparation of Formamide. 173 



Art. XVII. — The Preparation of Formamide from Ethyl 

 Formate and Ammonium Hydroxide / by I. K. Phelps and 

 C. D. Deming. 



[Contributions from the Kent Chemical Laboratory of Yale University — clxi.J 



The action of ammonia on an ester is a typical method for 

 the formation of an acid amide. Hofmann* states that this 

 reaction is particularly easy when the ester itself is somewhat 

 soluble in water; but that in the case of ethyl formate and 

 aqueous ammonia, when allowed to stand at the ordinary temper- 

 ature, a considerable part of the acid amide is hydrated to 

 ammonium formate, and the amount of acid amide formed is 

 accordingly diminished. He further states that this hydration 

 goes on to such an extent that a yield much in excess of 70 per 

 cent is impossible. 



The work given here records the results of experiments 

 which show that such hydration during reaction may be 

 avoided and the formamide may be obtained in amount equal 

 to that indicated by the theory for the action from ethyl formate 

 and ammonia. 



Ethyl formate for use in this work was prepared by treating 

 commercial sodium formate with a mixture of absolute alcohol 

 and concentrated sulphuric acid. The crude product obtained 

 as a distillate was f ractioned and portions found to boil between 

 53° and 56° were treated with fused calcium chloride to remove 

 water and alcohol, and redistilled after filtering from the cal- 

 cium chloride. This distillate was then treated with dry 

 ammonia gas obtained by boiling concentrated ammonium 

 hydroxide in a flask connected with a return condenser and 

 leading the ammonia gas obtained in this way through a lime 

 tower. The ammonium formate precipitated was separated by 

 filtration, and then, by fractional distillation, pure ethyl formate 

 distilling within two-tenths of a degree was obtained free from 

 ammonia gas or other impurity. 



In all the experiments recorded in the table definite weights 

 of the pure ethyl formate, chilled in an ice and salt mixture, 

 were treated with ammonium hydroxide of known strength 

 similarly chilled, and the temperature of the mass was not allowed 

 to rise above 0° until after the reaction between the formate 

 and the ammonia solution had been largely completed. The 

 formamide produced in each case was obtained by separating 

 from impurities by fractioning in vacuo in the usual way and 

 distilling the residue after the low-boiling impurities, largely 

 ammonia, ethyl formate, alcohol, and water, had been removed. 

 *Berichte, xv, 977. 



Am. Jour. Sci.— Fourth Series, Vol. XXIV, No. 140.— August, 1907. 

 12 



