280 Pheljps and Tillotson, Jr. — Cyanacetic Acid. 



to dryness at a high temperature. However, it may be quickly 

 and conveniently evaporated by heating with a water bath at 

 70°-80° under diminished pressure, in which case the cyan- 

 acetic ester formed is of 90-95 per cent purity. Experiments 

 (2), (3) and (4) of series A were performed under such condi- 

 tions. If pure cyanacetic ester is to be obtained, the excess of 

 mineral acid must be removed by adding sodium acetate. In 

 this case the yield is not so good, but the ester, after fractioning 

 under diminished pressure, is pure ethyl cyanacetate. This 

 procedure was followed in experiments (4) and (5) of series JB. 

 Pure cyanacetic acid was obtained from the ester prepared 

 in this way for use in an earlier paper* on the esterification of 

 cyanacetic acid. Two parts of water with one of ester and a 

 few drops of nitric acid were heated at a temperature of about 

 60° for some time after the mixture had become homogeneous. 

 The solution was then evaporated in an open dish, at a tem- 

 perature of 50°-60°, to the point of saturation. The cyanacetic 

 acid which separated on cooling was recrystallized from a mix- 

 ture of ether and chloroform. In this manner pure cyanacetic 

 acid, melting at 66 , l°-66 , 4° (corrected), was obtained in quantity 

 and in good yield. 



* This Journal, xxvi, 264. 



