Phelps and Tillotson, Jr. — Cyanacetic Acid. 279 



account, the reaction between sodium chloracetate and potas- 

 sium cyanide was practically quantitative. It is therefore 

 possible to calculate from the amount of malonic ester obtained 

 from the chloracetic acid used, the amount of cyanacetic ester 

 which might be expected from 200 grm. of the same quality of 

 chloracetic acid. A series of seven experiments similarly 

 carried out gave an average of 87'1 per cent of malonic ester, 

 with a loss inherent in the process of converting the cyanacetic 

 to the malonic ester of 4*2 per cent. This gives 309*32 grm. 

 of malonic ester, which is equivalent to 218*57 grm. of cyanacetic 

 ester from 200 grm. of chloracetic acid. The loss sustained by 

 the process employed for the recovery of the ester from the 

 crude product obtained in the esterification flask, has been shown 

 in a former paper* to be 1*67 grm. for 70 grm. of cyanacetic 

 ester, and is presumably 5 grams for the 218*57 grm. under 

 consideration in these experiments. Thus if the ester formed 

 is pure ethyl cyanacetate, we should not expect to obtain more 

 than 213 '57 grm., and higher yields may be explained by the 

 conversion of some of the cyanacetic ester into malonic ester. 

 This explanation is supported by the analyses, given above, of 

 the ester obtained in experiment (2) of series A, and appears 

 justified since in the experiments of series A there was an 

 excess of sulphuric acid while the aqueous solutions of cyan- 

 acetic acid were being evaporated to dryness. The higher 

 yields obtained in experiments (2) and (3) of series B are 

 ascribed to the formation of sodium malonate from sodium 

 cyanacetate in the hot alkaline solution. In these experiments 

 the reaction took place slowly for a period of fifteen to twenty 

 minutes, which allowed more hydrolysis to take place than in 

 experiments (4) and (5) of series B, in which the action was 

 over in five minutes or less. The lower results in experiments 

 (4) and (5) of series B are explained on the assumption that the 

 cyanacetic acid, reacting with the excess of sodium acetate, 

 forms an equilibrium mixture and, since the sodium cyanacetate 

 is not dissolved by the alcohol, a loss occurs. 



The results of the work here described are in agreement with 

 those of a former paper, which show that potassium cyanide and 

 sodium chloracetate react quantitatively in alkaline solution at 

 110°. They also show that cyanacetic ester of high purity may 

 be prepared in large amounts, and in good yield, from mono- 

 chloracetic acid if precautions be taken to minimize the trans- 

 formation to malonic acid. To this end the reaction between 

 sodium chloracetate and potassium cyanide should take place 

 quickly, the alkaline solution of sodium cyanacetate should not 

 be boiled for a long time, and the solution of cyanacetic acid, 

 containing an excess of mineral acid, must not be evaporated 



* This Journal, xxvi, 264. 



