RECENT WORK l\ AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY. 



On the formation of ammonia from the elements, V. IIahkk and G. \ w 

 Oordt {Ztechr. Anorgan. Chem. t M [1905), No. 4, /'/>■ - ; /'/ S78,figs. S; abs. in Chem. 

 Ztg., .".) i 1905), No. /'<'. Repert. No. 12, p. 162). — The ammonia equilibrium al various 

 temperatures up to 1,020° C. was restudied. a 



The ammonia content of a mixture of nitrogen, hydrogen, and ammonia in equi- 

 librium under a pressure of one temperature was found to be 98.51 per cenl at 27 

 ( '.. 8.72 per cent at :;l'7° C, 0.2] per cent at 627° ('., 0.024 per cent at 927 I '.. and 

 0.012 percent at 1,020° C. It is claimed that the reversible reaction Ca V : ; 1 1 ^ 

 MCall.. N" a takes place readily at red heat in connection with the reaction N. 3H 

 •_'N 1 1 ,. Calcium compounds of nitrogen assist in synthesis of ammonia at such high 

 temperatures as to make their use impracticable. Manganese may possibly proveof 

 value as a catalyser in such reactions, although the high temperatures required with 

 this Bubstance, as with calcium compounds, render its use of doubtful practicability. 



The direct synthesis of ammonia, E. I*. Perman (Proc. Roy. Soc. [London], Ser. 

 A. :>: ( i9<>:,\ y No. .1 508, />/>. 167-174)- — This article records the results of attempts 

 to synthesize ammonia with a view to determining whether there is a state of equi- 

 librium between ammonia and its constituent elements at various temperatures 

 ranging as high as 1,100° ('. The experiments were conducted with carefully dried 

 and purified mixtures of nitrogen and hydrogen prepared I 1) by decomposing ammo- 

 nia in red-hot iron tubes, and | 2 i by mixing 1 volume of nitrogen obtained by heating 

 am moil i uni chlorid and so. hum nitrite and 3 volumes of hydrogen obtained by action 

 of potash solution on metallic aluminum. 



'Idie Influence not only of different degrees of temperature hut also of the presence 

 of various catalyzing agents was studied. ( omparative studies of synthesis by explo- 

 sion and by electric discharges were also made. 



The author concludes from the results obtained that ammonia can not he synthe- 

 sized by heat excepl under certain special conditions. He therefore regards the 

 decomposition of ammonia by heat as an irreversible reaction. 



He shows that " ammonia may be synthesized in small quantities from its constituent 

 elements (a) by heating with many of the metals, (b) by exploding with oxygen, 

 ['•) by Bparking. These are reversible reactions. 



••It would appear that the synthesis of ammonia is effected only when the gases 

 are ionized: the ionization would lie brought about by sparking, or i>\ tin high tem- 

 perature of an explosion of hydrogen and oxygen. The immediate decomposition of 

 the ammonia formed would he prevented by its sudden cooling. The metals in the 

 presence of moisture also produce 'nascent' or ionized hydrogen. 



" It does not appear that nitrids of the metals form an intermediate stage in the 

 formation of ammonia, for it was found that metals readily forming nitride, 

 magnesium, did not produce more ammonia than the others. 



For account of previous studies see Ztschr. Anorgan. ("hem.. 4.". | L905), \>. 111. 



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