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



of the table, it was accomplished under diminished pressure 

 by heating the flask in a water bath at 70-80°, collecting the 

 distillate in a side-necked receiver which was kept cool by a 

 stream of water flowing over it continuously. The salt which 

 had been filtered off from the water solution was shaken up in 

 a flask with 200 cm3 of 95 per cent alcohol, filtered, and the 

 salt washed on the filter with 100 cm3 of alcohol of the same 

 strength. These alcoholic solutions were then added to the 

 residue, obtained by evaporation of the water solution, warmed 

 in a water bath and shaken till homogeneous. The insoluble 

 salt was filtered off, shaken up again with 100-200 cm3 of hot 

 95 per cent alcohol, and again filtered. The combined alco- 

 holic solutions contained in a liter flask were then freed from 

 alcohol, water, and low-boiling products by heating under 

 diminished pressure with a water bath at 60°, collecting the 

 distillate as before. The residue, consisting chiefly of cyan- 

 acetic acid, cyanacetic ester, and some sodium or potassium 

 salt, was treated by the method described in a former paper* 

 for the conversion of cyanacetic ester to malonic ester. For 

 these experiments, 600 cm3 of absolute alcohol with 5 cm3 of 

 sulphuric acid, sp. gi\ 1*84, were placed with the product 

 obtained as described above, in a two liter flask fitted with a 

 reflux condenser and kept cool in a mixture of ice and salt, and 

 the solution saturated with gaseous hydrochloric acid, dried 

 by bubbling through concentrated sulphuric acid. At the end 

 of about twelve hours saturation was usually complete. The 

 ice mixture was then replaced by a water bath and the solution 

 boiled under the return condenser for two hours, passing the 

 current of hydrochloric acid through the mixture continuously. 

 The precipitated ammonium salt was then filtered off, shaken 

 up with 100 cm3 of absolute alcohol, filtered again and washed 

 with absolute alcohol. The alcoholic solutions were then 

 collected in a liter flask fitted for esterification, as described 

 in a former paperf from this laboratory, and 700 cm3 of abso- 

 lute alcohol distilled during a period of three to four hours 

 through the solution of ester, which was kept at a temperature 

 of 100-110°. The resulting product was purified by treating 

 with ice and a solution of sodium carbonate and shaking out 

 w T ith ether. The ether and all low-boiling products were then 

 removed and the pure malonic ester distilled under diminished 

 pressure, as described in the paper to which reference has 

 been made. The ester obtained in this manner boiled within 

 reasonable limits and was nearly pure ethyl malonate. 

 Further evidence of its purity is furnished by the fact that, on 



* This Journal, xxvi, 143. fThis Journal, xxiv, 194. 



