1872.] 



History of the Ethylene Bases. 



427 



Ethylene sulphocarbamide, ethylene urea. — When a solution of the bi- 

 sulphide of carbon compound of ethylenediamine is boiled with a metallic 

 salt (mercury chloride for example), sulphuretted hydrogen is eliminated, 

 whilst at the same time a small quantity of carbon bisulphide distils, and 

 there remains in solution a salt of ethylenediamine and the metallic com- 

 pound of a new body still containing sulphur. 



A similar change is produced by boiling with dilute acids, but in this 

 instance much carbon bisulphide is evolved. Finally, the decomposition 

 may also be effected by boiling with water ; in this case scarcely any thing but 

 sulphuretted hydrogen is given off, the product of the reaction consisting 

 almost entirely of the above-mentioned new sulphur body, which can by 

 this means be easily obtained in a pure state. 



If the aqueous solution be allowed to cool, when sulphuretted hydrogen 

 has ceased to be evolved, beautiful white prismatic crystals having an ex- 

 tremely bitter taste are deposited ; they are soluble with difficulty in ether, 

 but easily so in alcohol. Their melting-point is 1 94°; at a higher temperature 

 they are decomposed. This substance still contains sulphur which cannot 

 be removed even by boiling with lead oxide in an alkaline solution, and is 

 only detected by fusion with potassium nitrate. Analysis of the body dried 

 at 100° leads to the formula 



CS i 



c 3 h 6 n 2 s=c 2 h 4 [n 2 . 



H 2 J 



The new substance, which may be considered as ethylene sulphocarbamide 

 or ethylene sulpho-urea, is thus seen to be formed from the carbon bisulphide 

 compound by the elimination of one molecule of sulphhydric acid, 



C 3 H 3 N 2 S 2 =C 3 H 6 N 2 S+H 2 S. 



The same body, as already mentioned, is produced by boiling the carbon 

 bisulphide compound with metallic salts or with acids, the by-products 

 ethylenediamine and carbon bisulphide, always formed in larger or smaller 

 quantity, belonging to a secondary reaction, in which the original compound 

 is resolved into its constituents. Ethylene sulphocarbamide crystallizes un- 

 changed from its solution in acids, but combines with silver nitrate and 

 mercury chloride, forming crystalline compounds. The mercury salt having 

 been frequently prepared in the attempts to obtain the mustard-oil has 

 been repeatedly analyzed. Probably several double salts exist ; but under the 

 conditions in which I have operated a compound of two molecules of the 

 urea with three molecules of mercury chloride, 



2C 3 H C N 2 S, 3HgCL, 

 appeared to be the principal product. 



Platinum chloride, even in very dilute solutions, gives rise to a bright, 

 yellow amorphous precipitate, which can be heated to 100° without under- 

 going decomposition. Its composition is 



2C 3 H C N 2 S, PtCl 4 . 



VOL. XX. 2 I 



