Cyanogen flame

Since it appears probable that the ionization processes in hydrogen flames are attributable to traces of hydrocarbon, the formation of CHO+ will explain the natural ionization in almost every flame system which has been studied. The only notable exceptions are the dry carbon monoxide or cyanogen flames, and there has been very little qualitative work on these systems. 

Other ionic recombination reactions have been postulated without any measurements, for example in cyanogen flames the process... 

Apart from the interferences which may arise from other elements present in the substance to be analysed, some interference may arise from the emission band spectra produced by molecules or molecular fragments present in the flame gases in particular, band spectra due to hydroxyl and cyanogen radicals arise in many flames. Although in AAS these flame signals are modulated (Section 21.9), in practice care should be taken to select an absorption line which does not correspond with the wavelengths due to any molecular bands because of the excessive noise produced by the latter this leads to decreased sensitivity and to poor precision of analysis. 

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... 

Brown PN, Jayson GG, Wilkinson MC. 1986. Determination of cyanogen and cyanogen chloride using gas chromatography with a flame ionization detector. Chromatographia 21 161 -164. 

Particularly important compounds have been studied by flame combustion calorimetry. Methane [92-94], ethanol [95], diethyl ether [96], carbon monoxide [92,93,97], hydrochloric acid [98], and water [93,97,99] are representative examples. With a few exceptions (HC1, H2O, D2O [100], SO2 [101], cyanogen [102,103], and some lower chloroalkanes [104,105]), measurements by flame combustion calorimetry have been limited to substances of general formula CaHbOc. 

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. 

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... 

Cyanogen evolved, burns with a peach coloured flame—cyanide of Hg or Ag. 

N 73.70% OB to C02 —24.05% white powder. V sol in w. Prepn is by reaction of Na azide with Br cyanogen at RT. When dry the salt bursts into flame it is also impact sensitive... 

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

Cyanogen is evolved (burns with violet flame and characteristic odour) very poisonous gas. 

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