Phelps and Tillotson, Jr. — Malonic Acid or its Ester. 271 



hydrolysis of the fractionated material, pure* malonic acid 

 was obtained. 



In experiments (3), (4) and (5) in series A, (1) and (2) in 

 series E, and (2) in series C of the table, the reaction between 

 the sodium chloracetate and potassium cyanide was made to 

 take place at a temperature of 90°-95°, by allowing the cold 

 solution of chloracetate to run slowly from a separatory funnel 

 into the hot cyanide solution, an operation which took from 

 fifteen to twenty minutes. In the other experiments the two 

 solutions were mixed and the reaction allowed to take place 

 vigorously, the temperature under these conditions reaching 

 110°. It was noticed in this reaction that if the chloracetate 

 solution was distinctly alkaline a nearly colorless solution re- 

 sulted, while if acid considerable color developed. The amount 

 of color seemed to increase with the length of time of the 

 reaction. Thus when the solutions were mixed and a vigorous 

 action took place, less color resulted than when the reaction 

 went at 90°-95° for fifteen minutes, but even then the color- 

 ation was small in comparison to that formed in experiments 

 not recorded in the table, in which the reaction was made to 

 take place at the temperature of ice water during a period of 

 twelve hours. The color is possibly due to dark-colored poly- 

 meric products formed from hydrocyanic acid. Hence it is 

 advantageous to allow the reaction between potassium cyanide 

 and sodium chloracetate to proceed in alkaline solution at a 

 temperature of about 100°. But these conditions are favorable 

 for the conversion of the cyanacetate to a malonate, which is 

 to some extent decomposed in the hot alkaline solution as shown 

 by Yan't Hoff,f who explained the decomposition as taking 

 place according to the following equation : CH 2 (COOK) 2 + 

 KOH = CH 3 COOK + K 2 00 3 . For this reason prolonged 

 boiling after the reaction is over is not desirable. On acidi- 

 fying, the slight excess of sulphuric acid produces a small 

 amount of hydrochloric acid, which, in the process of evapo- 

 ration of the aqueous solution of cyanacetic acid, may also 

 cause the formation and decomposition of some malonic acid. 

 This is shown in experiment (1) of series A, in which the acid 

 solution was evaporated on a steam bath. When the volume 

 of liquid became small, decomposition was apparent, through 

 the escape of bubbles of carbon dioxide. This decomposition 

 was minimized in all the remaining experiments, except exper- 

 iment (4) of series A, by evaporating at a lower temperature, 

 under diminished pressure. In order, if possible, to entirely 

 prevent this decomposition through the hydrolyzing effect of 

 the strong acid, the excess of sulphuric acid was removed, in 

 * This Journal, Phelps and Weed, xxvi, 138. f Berichte, vii, 1382. 



