ETHYLENE SEKIES. 115 



temperature. Can be most easily prepared by conduct- 

 ing the gas into an alcoholic solution of iodine, to 

 which is added an excess of iodine. Colorless crys- 

 tals, fusing at 73, which, when kept in a dark place, 

 slowly turn yellow. Exposed to the light, this dis- 

 coloration takes place rapidly. Sublimable ; above 

 80, however, it is resolved into iodine and ethylene. 



Ethylene nitrite, C 2 H 4 (^0 2 ) 2 . Is produced by 

 direct combination of ethylene with hyponitric acid. 

 Four-sided prisms, which fuse at 37.5. 



Chlornitrocarbon, C 2 C1 4 (T0 2 ) 2 . By heating carbon 

 chloride C 2 C1 4 with hyponitric acid in sealed tubes to 

 110-120. Colorless, crystalline mass. At 140 it is 

 resolved into C 2 C1 4 and hyponitric acid. 



Ethylene cyanide, C 4 H 4 N 2 = C 2 H 4 (CK) 2 . Is ob- 

 tained by heating ethylene chloride, or better, bromide, 

 in an alcoholic solution with potassium cyanide. 

 Crystalline mass, fusing at about 37. * Not volatile, 

 without undergoing decomposition. Heated with an 

 alcoholic solution of potassa, it yields ammonia and 

 potassium succinate ; it combines with nascent hydro- 

 gen, forming butylene diamine C 4 H 8 (NH 2 ) 2 . 



2. Propylene. 

 C 3 H 6 CH 3 .CH:CH 2 . 



Is produced together with the homologous hydrocar- 

 bons from a large number of organic bodies, when 

 these are distilled either alone or mixed with lime. It 

 can be obtained pure by heating glycerin with phos- 

 phorus iodide, or by heating the allyl iodide C 3 H 5 I, 

 which is formed simultaneously with it, with mercury 

 or zinc and fuming hydrochloric acid ; or, most readily, 

 by heating isopropyl iodide with an alcoholic solution 

 of potassa on a water-bath. It is also produced together 

 with ethyl bromide by the action of zincethyl on 

 bromoform. Colorless gas, with an odor similar to 

 that of ethylene; condensable by pressure, but is still 



