24:4: 



Phelps and Tillotson, Jr. — Malonic Acid. 



boiling within two-ten tlis of a degree, were hydrolyzed by 

 heating at a temperature of about 50°, a mixture of ester and 

 water in nearly equal amounts with a few drops of nitric acid, 

 for some time after the mixture became homogeneous. The 

 solution was then transferred to a porcelain dish and evapo- 

 rated to the point of saturation at a temperature not exceed- 

 ing* 60°, filtered while hot, and stirred while cooling. After 

 recrystallizing from water, the acid was dried, first in the air, 

 and then to constant weight in a desiccator over sulphuric acid. 

 The malonic acid prepared in this manner was proved to be 

 pure by titrating it against standard sodium hydroxidef and 

 barium hydroxide solutions. 



B 



Vv 



V 



cut. A is a glass tube l cm in diameter, drawn together at either end, and 

 held in place in the column by three " tears " fused to it. B is a small glass 

 rod bent into a U shape wide enough to slip easily into the column. To the 

 bottom of the U are fused one or more crosspieces of the same small glass 

 rod, thus forming a grating which allows a ready escape for the vapors and 

 the return of condensed liquid. The number of crosspieces necessary varies, 

 obviously, with the internal diameter of the column and the size of the 

 beads used. This device is also useful in connection with constricted side- 

 necked flasks, since very little constriction is sufficient to hold it in place. 

 The device can be varied for introducing a bead column in the side neck of 

 a Claisen flask by lengthening the upright rods sufficiently for the device to 

 be held in the angle of the side-neck tube. This modification obviates the 

 necessity of constricting the neck in this case. Even in distilling high boil- 

 ing point liquids like diethyl malonic ester, when the amount of liquid flow- 

 ing back is large, liquid does not collect in such a column. In practice, B 

 seems preferable to A on account of the more ready back flow of liquid. 



* F. Lamouroux, Compt. Eend., cxxviii, 998. 



f This Journal, xxvi, 138. 



