Chemistry of Hydrodesulfurization

S-ring not Opened S-ring Opened Proton Attack(exo) 

The hydrogenative pathway involves the initial hydrogenation of one or more of the carbon-carbon double bonds adjacent to the sulfur atom in the aromatic system. Hydrogenation destabilizes the aromatic ring system, weakens the sulfur-carbon bond and provides a less sterically hindered environment for the sulfur atom. Metal insertion is thus more facile. 

Alkvl Benzothiophenes Relative Reactivity Alkvl Dibenzothlopenes Relative Reactivity 

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Current emphasis in hydrodesulfurization of fuels has generated considerable interest in the reactions of molybdenum compounds with hydrogen sulfide or mixtures of H2S/H2. The following section will outline some of the pertinent reactions of molybdenum compounds with hydrogen sulfide or mixtures of H2S/H2. Details of the chemistry of hydrodesulfurization catalysts containing molybdenum are referenced later in this report. 

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