Cyanogen-oxygen flame

Origin of Ions in Nonhydrocarbon Flames. Of flames which do not contain hydrocarbons, only cyanogen/oxygen flames have so far been found to contain levels of natural ionization comparable with those... 

Hirschfelder et al. [7] reasoned that no dissociation occurs in the cyanogen-oxygen flame. In this reaction the products are solely CO and N2, no intermediate species form, and the C=0 and N=N bonds are difficult to break. It is apparent that the concentration of radicals is not important for flame propagation in this system, so one must conclude that thermal effects predominate. Hirschfelder et al. [7] essentially concluded that one should follow the thermal theory concept while including the diffusion of all particles, both into and out of the flame zone. 

In the 1950 s, work in this area was concerned primarily with the grosser features of cyanogen-oxygen flames, and did not lead to quantitative information which could help to determine the kinetics and mechanism of the reaction " " . 

The cyclotron resonance studies of Bulewicz and Padley indicate that the ionization in a low-pressure cyanogen/oxygen flame is in excess of the thermal level though this contradicts some early work in the field of gas chromatography. They found a dependence of electron combination on the square of the pressure, which was held to indicate that ions were produced in a termolecular process. Several possible reactions were postulated but no kinetic data were presented. Work on carbon monoxide flames has indicated the widespread occurrence of CHO+ even in supposedly dry flames. 

The classic source is a chemical combustion flame such as an acetylene-air flame. Table 2 shows flame temperatures for various fuels and oxidants. In today s instruments, acetylene-air and acetylene-nitrous oxide are the most common fuel-oxidant mixtures. In general, flames are considered relatively low-temperature sources (2000-3000°C) and have their greatest utility in determination of alkali metals and alkaline earth metals. (The cyanogen/oxygen flame shown in the table is considered an exotic flame and is rarely used in analysis both because of the toxicity of the fuel as well as the high production rate of CO as a combustion byproduct.)... 

For a thorough study of the cyanogen-air and oyanogen-oxygen flames, see Reis,... 

Cyanogen is a highly flammable gas. It forms explosive mixtures with air, LEL 6.6%, UEL 32% by volume. Reactions with oxygen, ozone, fluorine or other strong oxidizing agents can be explosive. Also, it can explode when exposed to spark, flame or heat. 

The nitrous oxide-acetylene flame is both hot and reducing. A characteristic red, interconal zone is obtained under slightly fuel-rich conditions. This red feather is due to emission by the cyanogen radical. This radical is a very efficient scavenger for oxygen, thus pulling equilibria such as... 

Free Cyanogen.—When mercuric oxide is heated, oxygen is set free as a gas and metallic mercury is left. A similar change occurs when mercuric cyanide is heated. Mercury is left and a gas is given off which is extremely poisonous, colorless, soluble in water, and which burns with a blue flame. This substance is known as cyanogen and has the composition (CN)2. 

Combustion of 100% ozone, 6 cc. per second, in excess of cyanogen (temperature of flame 5200 K.) C. Combustion of pure oxygen, 6 cc. per second, in excess of cyanogen... 

Dixon and H. F. Lowe found that dry carbon dioxide, but not moist, is dissociated to the extent of 39 per cent, by electric sparks. Dixon found that a dry mixture of carbon monoxide and oxygen united completely but without flame in contact with white-hot platinum wire, freed from occluded hydrogen, but a silver wire may be fused electrically in the mixture without effect. A dry mixture of cyanogen and oxygen is exploded by an electric spark, and the flame of the dry mixture, analysed on a moving photographic film, is identical with that of a moist mixture. ... 

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