Catalysis sulfides oxidation

Sulfides play an important role in hydrotreating catalysis. Whereas oxides are ionic structures, in which cations and anions preferably surround each other to minimize the repulsion between ions of the same charge, sulfides have largely covalent bonds as a consequence there is no repulsion which prevents sulfur atoms forming mutual bonds and hence the crystal structures of sulfides differ, in general, greatly from those of oxides. 

Federsel, H.-J. and Larsson, M. An Innovative Asymmetric Sulfide Oxidation The Process Development History behind the New Antiulcer Agent Esomeprazole in Asymmetric Catalysis on Industrial Scale, Blaser, H.U. and Schmidt, E. (Eds). Wiley-VCH New York, 2004, 413 36. 

Legros,)., Dehli, J.R. and Bolm, C. (2005) Applications of catalytic asymmetric sulfide oxidations to the syntheses of biologically active sulfoxides. Advanced Synthesis Catalysis, 347,19-31. 

Federsel H-J, Larsson M. An innovative asymmetric sulfide oxidation the process development history behind the new antiulcer agent esomeprazole. In Asymmetric Catalysis on Industrial Scale. Blaser H-U, Schmidt E, eds. 2004. Wiley-VCH, Wein-heim, Germany, pp. 413-436. 

Sulfide-mineral oxidation by microbial populations has been postulated to proceed via direct or indirect mechanisms (Tributsch and Bennett, 1981a,b Boon and Heijnen, 2001 Fowler, 2001 Sand et al., 2001 Tributsch, 2001). In the direct mechanism, it is assumed that the action taken by the attached cell or bacterium on a metal sulfide will solubilize the mineral surface through direct enzymatic oxidation reactions. The sulfur moiety on the mineral surface is oxidized to sulfate without the production of any detectable intermediates. The indirect mechanism assumes that the cell or bacteria do not act directly on the sulfide-mineral surface, but catalyze reactions proximal to the mineral surface. The products of these bacterially catalyzed reactions act on the mineral surfaces to promote oxidation of the dissolved Fe(II) and S° that are generated via chemical oxidative processes. Ferrous iron and S°, present at the mineral surface, are biologically oxidized to Fe(III) and sulfate. Physical attachment is not required for the bacterial catalysis to occur. The resulting catalysis promotes chemical oxidation of the sulfide-mineral surface, perpetuating the sulfide oxidation process (Figure 1). 

Table 9.7. I Homogeneous, surface and enzyme catalysis of carbon dioxide hydration, hydrogen sulfide oxidation and Mn oxidation... 

Parameter estimates for power law modeling of hydrogen sulfide oxidation on activated carbons [124]. Reprinted with permission flom V. Meeyoo, J.H. Lee, D.L Trimm, N.W. Cant. Catalysis Today, 44 (1998) 67... 

Chiral sulfur ligands (S-, S,N-, S,0-heterocycles and heterocycles bearing S-containing substituents) for asymmetric catalysis 07CRV5133. Oxidation of sulfides to sulfoxides 05X1933,05X8315. 

---