NITROGEN PRODUCTS 127 



pressure (becoming, for example, 18 per cent, at 200 atmos- 

 pheres at 500), undertook elaborate investigations, supported 

 financially by one of the large chemical companies of Ger- 

 many, first, to develop large scale apparatus which would with- 

 stand these high pressures, and secondly, to discover a contact- 

 agent or catalyst which would cause the hydrogen and nitrogen 

 to combine rapidly at a fairly low temperature. After years 

 of research and the expenditure of two or three millions of 

 dollars, the difficulties were largely overcome, and a practical 

 commercial process was developed. The hydrogen required 

 in this process is one of the chief factors in the cost of pro- 

 duction of the ammonia. It was manufactured by injecting 

 steam into a furnace containing red-hot coke, mixing the gases 

 so produced with a large excess of steam, passing them over a 

 contact-agent whereby the carbon monoxide (CO) present is 

 converted into carbon dioxide (CO 2 ), and removing the latter 

 from the gases by scrubbing them with cold water at a pressure 

 of 30-50 atmospheres. The chemical changes involved are 

 expressed by the equations 



The nitrogen required in the process was obtained by the dis- 

 tillation of liquefied air. 



3. The arc process like the synthetic process, involves an ex- 

 tremely simple chemical reaction; namely, 



At a very high temperature the nitrogen and oxygen of the 

 atmosphere can, as expressed by this equation, be made to 

 unite to form nitric oxide. In this case the effect of tem- 

 perature on the equilibrium is exactly the opposite of its effect 

 on the ammonia equilibrium. The higher the temperature, the 

 more nitric oxide is obtained ; but there is very little produced 



