278 Phelps and Tillotson^ Jr. — Cyanacetic Acid. 



acid acting on the chlorides present produces a small amount 

 of hydrochloric acid, which, in the process of evaporation, also 

 tends to the formation of malonic acid. In series A there was 

 a slight excess of sulphuric acid in each experiment. The ester 

 obtained, after fraction ing under diminished pressure, appeared 

 to contain malonic ester as shown by the following analyses: 



I. 0*5060 grm. of ester gave 5r5 cm3 of moist nitrogen at 21° and 

 762'6 mm . N = 11-39 per cent. 

 II. 0*5070 grm. of ester gave 51-2 cmS of moist nitrogen at 22° and 

 765*2 mm . ]ST = 11-52 per cent. 



Calculated for C.H 7 2 N, N = 12-40 per cent. 



In the experiments of series B, after adding a slight excess of 

 sulphuric acid, as indicated by logwood paper, enough of a 

 saturated solution of sodium acetate was added to destroy the 

 excess of sulphuric acid, logwood paper again being the indi- 

 cator. The ester obtained in this manner, after being fractioned 

 under diminished pressure, gave the following analyses : 



I. 0*5020 grm. of ester gave 55'2 cm3 of moist nitrogen at 23° and 

 762-3 mm . N = 12-47 per cent. 

 II. 0*5004 grm. of ester gave 55*0 cm3 of moist nitrogen at 20° and 

 7582 mm . N = 12-54 per cent. 



Calculated for C B H 7 2 N, N = 12-40 per cent. 



It is plain therefore that if pure cyan acetic ester is to be 

 obtained, the water solution of cyanacetic acid must not be 

 evaporated in the presence of mineral acids, but in the presence 

 of acetic acid no considerable decomposition takes place. The 

 operation is most conveniently performed under diminished 

 pressure, since the low temperature necessary to remove the 

 water under diminished pressure is unfavorable for the forma- 

 tion of malonic acid. 



Some loss always occurred during the distillation of the 

 alcoholic solution of cyanacetic acid. This loss has been shown 

 in the former paper,* on the preparation of malonic ester, to be 

 7'1 grm. of cyanacetic ester or about three per cent. It has 

 also been shown in a former paper,*)* that the loss inherent in 

 the process used for recovery of pure ester from the crude 

 product obtained in the esterification flask was 1*67 grm. for 

 70 grm. of pure ester or 2*4 per cent. Assuming that this 

 percentage error holds for large amounts, we have approxi- 

 mately 5 '4 per cent of cyanacetic ester lost during the pro- 

 cedure. 



In an earlier paper*); it was shown from the yield of malonic 

 ester obtained that if the purity of the chloracetic acid used and 

 the loss of malonic ester inherent in the process be taken into 



* This Journal, xxvi, 272. \ This Journal, xxvi, 265. 



\ This Journal, xxvi, 273. 



