510 Drushel and Knapp — Glycocoll and Diethyl Carbonate. 



by Clarke* was also tried but was found to be much less satis- 

 factory than copper hydroxide. In no case did the yield of 

 pure glycocoll exceed 55 per cent of the chloracetic acid used. 

 It does not seem possible to increase the yield of glycocoll by 

 changing the conditions of Kraut's method in the direction of 

 lowering the temperature or increasing the concentration of 

 ammonia during the reaction. 



Diethyl Carbonate. — Since cyanformic ester is readily con- 

 verted into aminoacetic ester by reduction, it seemed desirable to 

 examine the methods of preparing cyanformic ester. In 1895 

 Nefff obtained this ester mixed with some diethyl carbonate 

 by the action of potassium cyanide upon chlorformic ester in 

 25 per cent aqueous alcohol at —13°, allowing the temperature 

 to rise slowly during the course of the reaction to —2°. 

 Under these conditions only about 50 per cent of the chlor- 

 formic ester was converted into cyanformic ester. In our 

 experiments absolute alcohol was used, resulting in the abund- 

 ant formation of diethyl carbonate without any cyanformic 

 ester. Powdered potassium cyanide was covered in a flask 

 with absolute alcohol and then one equivalent of chlorformic 

 ester mixed with an equal volume of absolute alcohol was 

 slowly added in small portions through a reflux condenser 

 under a good draught hood. Heat was evolved, hydrocyanic 

 acid was given off and the reaction mixture became red in 

 color. The mixture was finally boiled for an hour on the water 

 bath to bring the reaction to completion. The residue was 

 then filtered off and the filtrate was fractionally distilled. The 

 first fractionation gave almost pure diethyl carbonate, probably 

 according to the equation C 2 H 6 C0„C1 + KCN + C 3 H 6 OH = 

 (C 2 H 6 ) 2 C0 3 + HCN + KC1. After "redistillation the product 

 boiled at 127°, and its identity as diethyl carbonate was further 

 established by determining its molecular weight; by determin- 

 ing its saponification equivalent as 59, its specific gravity as 

 0-968 at ■ 25° ; and finally by preparing urethane from the 

 product by the action of ammonia. 



No cyanformic ester could be isolated from the reaction 

 mixture and the yield of diethyl carbonate after purification 

 was 50 per cent of the chlorformic ester used. 



*H. T. Clarke, Org. Chem., p. 290. 

 \ Ann. Chem. Phurm., cclxxxvii, 308. 



