SUPPLEMENT. 



Art. XX Y. — On the Esterification of Malonic Acid ; by 

 I. K. Phelps and E. W. Tillotson, Jr. 



[Contributions from the Kent Chemical Laboratory of Yale Univ. — clxxxi.] 



Finkelstein* has shown that diethyl malonic ester may be 

 prepared by dissolving malonic acid in the least possible 

 amount of absolute alcohol before saturating with hydrochloric 

 acid gas. The excess of alcohol is then distilled off, the resi- 

 due poured into water, neutralized with sodium carbonate, and 

 extracted with ether. On evaporation of the ether, diethyl 

 malonic ester, boiling for the most part at 195°, is obtained. 

 He gives no quantitative results. Conradf has followed a pre- 

 cisely similar procedure, using the calcium salt of malonic acid 

 instead of the acid itself. The yield given is 70 per cent of 

 that theoretically possible. Quite recently BogojawlenskyJ, 

 by boiling a solution of malonic acid in alcohol under a return 

 condenser for six to seven hours, in the presence of anhydrous 

 copper sulphate or potassium pyrosulphate as dehydrating 

 agents, has obtained yields of malonic ester 68 per cent of that 

 theoretically possible. In former papers§ from this laboratory 

 studies of conditions giving high yields of the ethyl esters of 

 succinic and benzoic acids have been made. And, further, 

 the effect upon the quantity of ester produced, caused by vary- 

 ing three factors in the reaction, was shown. These factors 

 were, first, the quantity of alcohol, second, certain catalyzers, 

 and third, the period of the time of action. In this paper a 

 similar study of the esterification of malonic acid with ethyl 

 alcohol is recorded. For the preparation of pure malonic acid, 

 the diethyl ester was purified by repeated fractional distilla- 

 tions under atmospheric pressure. || Portions of malonic ester, 



*Ann., cxxxiii, 338. flbid., cciv, 126. 



JBerichte, xxxviii, 3344. 



§ This Journal, xxii, 368 ; xxiv, 194 ; xxv, 39. 



|| In distilling the ester, the following simple modification of the Hempel 

 bead column was found advantageous. To the lower end of the column, 

 which was 15 mm in diameter, was fused a glass tube 7 ram inside diameter and 

 5 cm long, the lower end of which was ground off at an angle. To prevent 

 the beads from falling through this tube, two devices were made use of. 

 Either A, shown by itself, or B, shown in position in such a column in the 



