Transactions of the Royal Society of Canada 



SECTION III 

 Series III MAY, 1922 Vol. XVI 



The Mechanism of the Catalysis of Hydrogénation hy Nickel 



By Maitland C. Boswell 



It is a well known fact that many compounds containing un- 

 saturated carbon atoms will, when heated along with gaseous hydrogen 

 to relatively high temperatures, combine with hydrogen to form 

 saturated compounds. Thus a mixture of ethylene and hydrogen 

 passed through a tube heated at 550°C. forms ethane. Sabatier (1) 

 discovered that metallic nickel prepared by the reduction of nickel 

 oxide by hydrogen at a temperature below 300°C. is an excellent 

 catalyst for this reaction, and that in its presence ethylene and hydro- 

 gen will combine with appreciable velocity at room temperatures, 

 while at loO°C. the velocity of combination is very great. Sabatier 

 and his students and other investigators have extended this catalytic 

 hydrogénation by nickel to a great variety of unsaturated compounds. 

 Among these processes which have assumed a large commercial 

 importance is the hydrogénation of unsaturated fats, the so-called 

 hardening of fats process, whereby the liquid fat olein present in such 

 liquid fats as cocoanut oil and cottonseed oil is transformed into the 

 solid fat stearin. 



The investigation, which is the subject of this paper, has for its . 

 object the determination of how the nickel functions in these hydro- 

 genations,^ — the mechanism of the reactions. 



As the numerous investigations on this subject have already 

 been dealt with exhaustively elsewhere, there is no necessity here to 

 do more in this regard than to review very briefly the outstanding 

 conclusions which have been arrived at by previous investigators. 

 Later in the paper these conclusions will be reconsidered and the 

 endeavour made, from the experimental data obtained in this labora- 

 tory, to show that some of the apparently contrary conclusions from 

 former researches can be reconciled, and brought into conformity with 

 another representation of the mechanism which is here proposed. 



Several investigators have measured the capacity of nickel and 

 other metals to absorb hydrogen and have connected this with the 

 catalvtic activity of nickel in hvdrogenation, the' hydrogen beipg^iir, . ^ 



1— c *- y\ 







