A MASS SPECTROMETRIC STUDY OF THE OXIDATION OF HYDROGEN SULPHIDE PART I. OBSERVATION AND IDENTIFICATION OF SOME INTERMEDIATES

The oxidation of hydrogen sulphide has been followed mass-spectrometrically by direct sampling from a reaction vessel having a small leak. In the neighborhood of the third explosion limit, there is a period of 8–12 seconds of accelerating reaction before the explosion; during this time peaks are observed to grow, disappearing after explosion. By using D2S/16O2 and H2S/18O2 mixtures, it has been shown that these peaks arise from the ions H2+, S2O+, H2SO+, S2+, and H2S2+. It is evident that the first two ions represent the intermediate formation of hydrogen and disulphur monoxide; the parents of the last three ions are discussed, and it is concluded that the most likely possibilities are H2SO2, S2, and H2S2. Only during the explosion itself is there any evidence for SO radical.