Reactions of O2 with sulfur compounds

Initial work on the slow oxidation of hydrogen sulfide was done in the 1930 s and directed toward establishing the explosion limits, length and nature of the induction period, autocatalycity, and nature of products. The work has been summarized briefly by Marsden and reviewed in greater detail by Grewer and Semenov . We will direct our attention, however, mainly to the later work which can be used to establish the kinetics and mechanism of the reaction, referring to early papers only when they are relevant to such ends. 

Emanuel et al. °, recorded an absorption spectrum during the course of the reaction and observed the same spectrum reported earlier by Schenk from an electric discharge through a mixture of SO2 and sulfur. Agreeing with Schenk, they ascribed the spectrum to the SO soecies or its dimer, S2O2 and proposed it was formed in what they called an elementary reaction 

Kondratieva and Kondratiev S argued that the species observed had to be the dimer, SjOj. Markovich and Emanuel S3 i34 that the S2O2 is 

The light emission was identified with the familiar SO + 0 afterglow. 

More careful work on the nature of the products of the electrical discharge passed through SO2 and S has forced the re-evaluation of these conclusions on the H2S oxidation. Meschi and Myers found that the major product in such a system was not S2O2, as had been believed, but S2O, and that this was the species responsible for the banded emission spectrum observed by Markovich and Emanuel and by Norrish and Zeelenberg. In the discharge system, such a product might be formed by direct combination  

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