[boswell] catalysis OF HYDROGENATION BY NICKEL 



Finally the apparatus was allowed to stand corked up for three 

 days along with the hydrogen remaining in the tube. Upon now 

 passing hydrogen at room temperature for one hour 0.0323 grams 

 water was obtained. 



There was still considerable oxygen remaining for on passing, at 

 the end of the experiment, hydrogen at 600°C. . 1214 g. water was 

 obtained. 



It is evident from this series of experiments that when nickel oxide 

 is reduced by hydrogen, the reduction occurs in two ways: (1) sur- 

 face nickel oxides are reduced leaving adsorbed hydrogen on the 

 nickel, and (2) the adsorbed hydrogen slowly reacts with the remaining 

 nickel oxide. It would also appear that this adsorbed hydrogen is 

 held, not only on the outer surface of the nickel, but on the inside of 

 particles for even after prolonged reduction there is still a relatively 

 large amount of water evolved on standing. It is also evident that 

 this hydrogen reacts to form free water only very slowly. 



Experiment 3. 



The object of this was to determine the amount of hydrogen 

 taken up at room temperature after nickel oxide has been reduced by 

 hydrogen. Nickel oxide was reduced for three and one half hours at 

 275°C. During the last half hour of this period 0.0076 g. water was 

 obtained. On standing over night in hydrogen at room temperature 

 75 c.c. of hydrogen was found to have been taken up. In five hours 

 more the pressure of hydrogen indicated a continuous adsorption of 

 hydrogen. 



This experiment was repeated when it was found that 40 c.c. 

 hydrogen was taken up during the night at room temperature. This 

 observation appears to be in harmony with that of Ross, Culbertson 

 and Parsons (7) who state that "at ordinary temperature hydrogen 

 is adsorbed in active nickel to a considerably greater extent than 



