The spectra of chilled hydrocarbon flames

It has been found that the spectrum of the outer cone of hydrocarbon flames struck back in a water-cooled steel burner shows the hydrocarbon flame bands in the ultra-violet which are usually known as the ethylene flame bands. Under suitable conditions these bands are relatively very strong, being almost the sole feature of the spectrum. Chemical tests show that the occurrence of these hydrocarbon flame bands is closely associated with the formation of a peroxide, probably an alkyl peroxide. The bands are not necessarily associated with the presence of aldehydes in the interconal gases. Various catalysts have little effect on the spectrum. A brief discussion on the nature of the emitter of the hydrocarbon flame bands is given. The present observations favour the radical HCO as the emitter, this being formed perhaps by the breaking up of peroxides in much the same way as CH is known spectroscopically to be formed in the breaking up of hydrocarbons.