FULMINIC ACID, Hcno or H 2 C 2 N 2 0 2, an organic acid isomeric with cyanic and cyanuric acids; its salts, termed fulminates, are very explosive and are much employed as detonators.
The researches of Liebig (1823), Liebig and Gay-Lussac (1824), and of Liebig again in 1838 showed the acid to be isomeric with cyanic acid, and probably (Hcno) 2, since it gave mixed and acid salts.
It is usually repre- "N :C -.OH sented by the inset formula and is closely related to cyanic acid and cyamelide, the relationships existing between the three compounds being shown in the diagram (see also A.
Hantzsch, Ber., 1906, 39, p. 139): Ordinary temperature Cyamelide (CNOH) 3 Cyanic acid CNOH HO ions 1 High Cyanuric acid Decomposes with temperature
CYANAMIDE, NC NH 2j the amide of normal cyanic acid, obtained by the action of ammonia on cyanogen chloride, bromide or iodide, or by the desulphurization of thio-urea with, mercuric oxide; it is generally prepared by the latter process.
Cyanic acid and cyanates >>
In this domain his first research was on the fulminates of mercury and silver, and his study of these bodies led him to the discovery of the isomerism of cyanic and fulminic acids, for the composition of fulminic acid as found by him was the same as that of cyanic acid, as found by F.
Other reactions which introduce carboxyl groups into aromatic groups are: the action of carbonyl chloride on aromatic hydrocarbons in the presence of aluminium chloride, acid-chlorides being formed which are readily decomposed by water to give the acid; the action of urea chloride Clï¿½COï¿½NH 2, cyanuric acid (CONH) 3, nascent cyanic acid, or carbanile on hydrocarbons in the presence of aluminium chloride, acid-amides being obtained which are readily decomposed to give the acid.
One of the earliest, if not the earliest, was the investigation, published in 1830, which proved the polymerism of cyanic and cyanuric acid, but the most famous were those on the oil of bitter almonds (benzaldehyde) and the radicle benzoyl (1832), and on uric acid (1837), which are of fundamental importance in the history of organic chemistry.
When Wohler, in 1825, analysed his cyanic acid, and Liebig his quite different fulminic acid in 1824, the composition of both compounds proved to be absolutely the same, containing each in round numbers 28% of carbon, 33% of nitrogen, 37% of oxygen and 2% of hydrogen.
There are polymers which have hardly any inter-relations other than identity in composition; on the other hand, there are others which are related by the possibility of mutual transformation; examples of this kind are cyanic acid (Cnoh) and cyanuric acid (Cnoh) 3, the latter being a solid which readily transforms into the former on heating as an easily condensable vapour; the reverse transformation may also be realized; and the polymers methylene oxide (CH 2 O) and trioxymethylene (CH20)3.
Both formula and experiment proved that an increase of pressure of one atmosphere elevated the transition point for about o 04° The same laws apply to cases of more complicated nature, and one of them, which deserves to be pursued further, is the mutual transformation of cyanuric acid, C 3 H 3 N 3 O 3, cyanic acid, Chno, and cyamelide (Chno).; the first corresponding to prismatic sulphur, stable at higher temperatures, the last to rhombic, the equilibrium-symbol being: cyamelide 1 .?
° cyanuric acid; the cyanic acid corresponds to sulphur vapour, being in equilibrium with either cyamelide or cyanuric acid at a maximum pressure, definite for each temperature.
Hydroxy-urea, N H2 CO NH OH, is produced from hydroxylamine and cyanic acid (W.
Its esters are formed by passing the vapours of cyanic acid into alcohols (W.
Investigation of the cyanic ethers (1848) yielded a class of substances which opened out a new field in organic chemistry, for, by treating those ethers with caustic potash, he obtained methylamine, the simplest organic derivative of ammonia (1849), and later (1851) the compound ureas.