RECENT ADVANCES IN SCIENCE 25 



Catalytic Reactions. — A new field of work has been opened 

 up in a series of investigations made by Lidov on the reactivity 

 of carbon (4). Lidov has attacked the question as to whether 

 carbon unites with nitrogen at the ordinary temperature. 

 Using finely-divided carbon from cotton or sulphite cellulose, 

 in which a metallic catalyst is deposited by having previously 

 moistened the carbonaceous material with a solution of ferrous 

 lactate and calcining in a current of hydrogen, he finds that 

 after the carbon has been sealed up with C0 2 -free air for 

 several months, reaction takes place in two successive stages. 

 At first the carbon unites with nitrogen to form active 

 a-monocyanogen, — C=N, and inactive /3-monocyanogen, — N = C. 

 In this stage the oxygen of the air takes no part, reaction being 

 due to the nitrogen atom. The second stage consists of the 

 addition of oxygen forming respectively a-oxan, O — C = N, 

 and /3-oxan, O — N = C. Under suitable conditions peroxan, 

 2 CN, can also be formed. 



a-monocyanogen is soluble in cuprous chloride solution, 

 and its oxidation product a-oxan is very similar to carbon 

 dioxide. The inactive compound is insoluble in cuprous 

 chloride solution, but its oxidation product /3-oxan is soluble. 

 /3-oxan differs from carbon dioxide in that its salts are easily 

 decomposed by heat, and it is not soluble in aqueous alkali. 

 The author claims that his results account for the variation 

 in the amount of nitrogen in the air at different times of the 

 year. Experiments have also been carried out with carbon 

 activated with other metals, chiefly lead and nickel. Carbon 

 activated with lead does not lose its activity for a very long 

 time, whereas that activated with iron and nickel loses its 

 activity rapidly, probably because the metal precipitated on the 

 surface of the carbon becomes converted into its higher oxide. 



The loss of activity with these latter metals is not, how- 

 ever, absolute, but is merely a matter of diminution in the 

 rate of reaction. These results are shown by the fact that the 

 amount of air treated with the activated carbon which is 

 required to precipitate barium hydroxide solution is always 

 less for lead than for iron or for nickel. Moreover, the density 

 of this mass of air is always less than that of the mass from 

 carbon activated with iron or nickel, and is on the average 

 very near the density of oxan. 



Another interesting observation in this connection is that 



