On the action of finely divided platinum on gaseous mixtures, and its application to their analysis

Abstract

In the first section of this paper the author describes the action of finely divided platinum, at common temperatures, on mixtures of hydrogen and olefiant gas with oxygen; of hydrogen and carburetted hydrogen with oxygen; of hydrogen and carbonic oxide with oxygen; of hydrogen and cyanogen with oxygen; of carbonic oxide and carburetted hydrogen with oxygen; of hydrogen, carburetted hydrogen and carbonic oxide with oxygen; and of the same with the addition of olefiant gas. From the experiments detailed under these several heads, it appears that when the compound combustible gases mixed with each other, with hydrogen, and with oxygen, are exposed to balls of platinum sponge, the several gases are not acted upon with equal facility; but that next to hydrogen, carbonic oxide is most disposed to unite with oxygen, then olefiant gas, and lastly carburetted hydrogen. By due regulation of the proportion of hydrogen, the author remarks, that it is possible to change the whole of the carbonic oxide into carbonic acid, without acting on the olefiant gas or carburetted hydrogen; he observes, however, that with respect to olefiant gas this exclusion is attended with some difficulty, and it is generally more or less converted into carbonic acid and water. The second section of this paper relates to the action of finely divided platinum upon gaseous mixtures at increased temperatures. In these experiments the gases, mixed with oxygen enough to saturate them, were severally exposed in small retorts containing a platinum sponge, and immersed in a mercurial bath, to a temperature which was gradually raised till the gases began to act on each other. It was thus found that carbonic oxide began to be converted into carbonic acid at about 300º; olefiant gas was decomposed at about 500º; carburetted hydrogen at a little above 555º; and cyanogen appeared to require a red heat.