Cyanogen

Preparation

Cyanogen is typically generated from cyanide compounds. One laboratory method entails thermal decomposition of mercuric cyanide: : Or, one can combine solutions of copper(II) salts (such as copper(II) sulfate) with cyanides; an unstable copper(II) cyanide is formed which rapidly decomposes into copper(I) cyanide and cyanogen. :

Industrially, it is created by the oxidation of hydrogen cyanide, usually using chlorine over an activated silicon dioxide catalyst or nitrogen dioxide over a copper salt. It is also formed when nitrogen and acetylene are reacted by an electrical spark or discharge.

Reactions

For the two less stable isomers of cyanogen, the order of the atoms differs. Isocyanogen (or cyanogen cyanide) is . It has been detected in the interstellar medium.

Addition of disulfur dichloride to cyanogen gives 3,4-dichloro-1,2,5-thiadiazole.

Paracyanogen

History

Cyanogen was first synthesized in 1815 by Joseph Louis Gay-Lussac, who determined its empirical formula and named it. Gay-Lussac coined the word "cyanogène" from the Greek words κυανός (kyanos, blue) and γεννάω (gennao, to create), because cyanide was first isolated by Swedish chemist Carl Wilhelm Scheele from the pigment Prussian blue. It attained importance with the growth of the fertilizer industry in the late 19th century and remains an important intermediate in the production of many fertilizers. It is also used as a stabilizer in the production of nitrocellulose.

Cyanogen is commonly found in comets. In 1910 a spectroscopic analysis of Halley's Comet found cyanogen in the comet's tail, which led to public fear that the Earth would be poisoned as it passed through the tail. People in New York wore gas masks, and merchants sold quack "comet pills" claimed to neutralize poisoning. Because of the extremely diffuse nature of the tail, there was no effect when the planet passed through it.

Safety

Like other cyanides, cyanogen is very toxic, as it readily undergoes reduction to cyanide, which poisons the cytochrome c oxidase complex, thus interrupting the mitochondrial electron transfer chain. Cyanogen gas is an irritant to the eyes and respiratory system. Inhalation can lead to headache, dizziness, rapid pulse, nausea, vomiting, loss of consciousness, convulsions, and death, depending on exposure. Lethal dose through inhalation typically ranges from 100 to.

Cyanogen produces the second-hottest-known natural flame (after dicyanoacetylene aka carbon subnitride) with a temperature of over 4525 C when it burns in oxygen.

References

References

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