DERIVATIVES OF CARBONIC ACID. 225 



when treated with water or caustic potassa, give up 

 the bromine and regenerate the ether. Heated with 

 alcoholic ammonia, the ether is decomposed into mer- 

 captan and ammonium sulphocyanate. When oxidized 

 with nitric acid, it yields ethylsulphurous acid (p. 51). 



Ethylene sulphocarbonate, CS.S 2 .C 2 H 4 , is formed 

 from the sodium compound and ethylene bromide or 

 chloride like the ethyl ether. Large, yellow crystals, 

 which fuse at 36.5. Slowly soluble in alcohol, easily 

 in ether and ether-alcohol. By oxidation with dilute 

 nitric acid, it is transformed into 



Ethylene oxysulpho carbonate, COS 2 .C 2 H 4 . Thin 

 plates fusing at 31, easily soluble in alcohol and ether. 

 Yields, when further oxidized with concentrated nitric 

 acid, disulphetholic acid (p. 141). 



Xanthogenic acid, C 3 H 6 OS 2 = OS j ^ H5 (Ethyl- 



disulphocarbonic acid). The potassium salt of this 

 acid separates in colorless, silky needles when carbon 

 bisulphide is added to a solution of caustic potassa in 

 alcohol. The free acid, separated from the potassium 

 salt by means of sulphuric acid at the ordinary tem- 

 perature, is oily, insoluble in water ; decomposes at 24 

 into alcohol and carbon bisulphide. 



{O C 2 TT 5 

 S C 2 H 5 



the action of ethyl chloride on potassium xanthoge- 

 nate. Colorless oil, boiling at 200. With ammonia, it 



yields xanthogenamide C 3 H 7 NOS = OS j jjfc a sub- 



stance which forms large crystals and fuses at 36. At 

 the same time there are formed ethyl sulphide and 

 ammonium sulphide ; when mixed with an alcoholic 

 solution of potassa, it gives the potassium salt of ethyl- 



( O C 2 H 5 



monosulpJiocarbonic acid, CS < ^W This salt can also 



be prepared by direct union of carbonic anhydride and 



