[boswell] catalysis OF HYDROGENATION BY NICKEL 13 



experiment controlled by analysis was now performed with this 

 catalyst which had now activated a considerable union of ethylene 

 and hydrogen. The mixture consisted of hydrogen 90 c.c, ethylene 

 180 c.c, nitrogen 300 c.c. Temperature 150°C. Time | hour. 



Volume of gas at beginning 570 c.c. 



Volume of gas at end 500 c.c. 



Reduction of volume 70 c.c. 



Composition of gas at end 



Ethylene 29% 



Hydrogen 5 . 6% 



Ethane 5.4% 



Nitrogen 60% 



Water obtained = 0.0164 g. = 22 c.c. hydrogen. 



5.6 

 Therefore, hydrogen present at end= -rzz X 500 = 28.0 c.c. 



hydrogen used up = 90 - 28 , = 62 . c.c. 



29 

 ethylene present at end= Tzrz X 500 =145 c.c. 



Therefore, ethlyene changed to ethane is equal to 180 — 145 = 35 c.c. 

 " 35 c.c. hydrogen was used in hydrogenating ethylene to 



ethane. 

 But 62 c.c. of hydrogen disappeared. 



Therefore, 62 — 35 c.c. hydrogen was used in some reactions other 

 than hydrogénation of ethylene = 27 c.c. 

 Water formed in this reaction = 0.0164 g. 

 equivalent to 22 c.c. hydrogen. 



Therefore, in this case the hydrogen used up in excess of that 

 used in the hydrogénation of ethylene was transformed for the greater 

 part into water. This amount of water could not have formed by the 

 very slow reaction of the adsorbed hydrogen on the unchanged nickel 

 oxide, as has already been shown. It probably comes from the 

 hydroxyl groups in the surface film on the particles. 



Here again the hydrogen used up in excess of that required for hydro- 

 génation of ethylene, is relatively large, and is very much greater 

 than would have disappeared in one half hour treatment of the same 

 nickel complex with hydrogen alone. Moreover, the equivalent of 

 this excess hydrogen was almost all evolved in the form of free water. 

 There accordingly was only a small amount of this excess hydrogen 

 remaining on the catalyser as adsorbed hydrogen. Once more the 

 conclusions arrived at under experiment (5) seem to be confirmed. 



