Sulfides H2S, CS2, COS, RSH Reduced sulfur

The radicals HSO and HSO2 quickly decompose (with O3 and O2) into several other radicals (HS, SO, HSO2 and OH k = 6 10 cm molecule s ) finally, SO2 is produced. Radical sulfur fast oxidizes A 5.265 = 2.1 10 cm molecule s ). 

It is self-evident that O reacts with O2 to give O3 and CO forms CO2 via OH attack. Finally, the oxidation of H2S is also relatively fast (2-3-day lifetime)  

Analog OH reacts with methanethiol (methyl mercaptan) CH3SH (k = 3.3 10 cm molecule s ). We can summarize that H2S is 100% converted into SO2 and CS2 with each 50 % transformed into SO2 and COS. 

The most important reduced sulfur species is DMS. Many studies have been carried out to clear the oxidation mechanisms shown in Fig. 5.28. The fate of radical intermediates such as CH3O, SO and CH3 have been described above, but many other radicals can only be grouped together within the term product on the right-hand side of the equation. Many molecules found in the reaction scheme can be identified from Table 5.18. Fig. 5.28 only shows the OH attack in addition, NO3 (nitrate radical) has been described as a very effective oxidizer. OH initiates two channels the H abstraction and the addition ks,no = 4.8 10 cm molecule s and A 5.27i = 2.2 10 cm molecule s .  

Two more channels that break down the DMS molecule are described into CH3 -l-CH3OH and CH3 + CH3SOH. Because of the nocturnal NO3 attack on DMS (H abstraction channel), its lifetime is short (only about one day). It is remarkable that via the abstraction channel only sulfate is seen at the end, whereas in the OH addition channel many stable organic sulfur species, such as methanesulfonic acid or methanesulfonate (MSA) and dimethylsulfoxide (DMSO) as well as dimethylsul-fone (DMSO2), can be identified. 

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