Chevrel phases heterogeneous HDS catalysts containing molecular clusters

6 Chevrel phases heterogeneous HDS catalysts containing molecular clusters 

The thiophene HDS activities (at 400 °C, 1 atm H2) of a number of Chevrel phases were found ° ° to be comparable with those of unsupported M0S2 and 

The group of transition metal. sulfide clusters can be viewed as constituting discrete molecular fragments of the metal sulfide phases present in heterogeneous catalysts. However, with a few very notable exceptions, it has so far been difficult to identify sulfide cluster chemistry that directly reflects the mechanisms of HDS. The main exception is the desulfurization of e.g. thiophene by the sulfide vacancy cluster [(Cp )2Mo2Co2(CO)4(//3-S)2( 4-S)], a reaction which closely mimics the mechanism envisaged for the heterogeneous metal sulfide catalysts. 

The financial and environmental importance of hydrodesulfurization reactions assures continued interest in HDS research. The knowledge of the mechanisms in commercial HDS reactions is still considerably limited determination of the intimate mechanisms of these reactions constitutes a formidable challenge. The use of metal clusters as models for HDS catalysts is continuously developing and we might therefore expect that several new model systems will be investigated in the future. 

Funding for research on hydrodesulfurization provided by the European Union (TMR Network MECATSYN - Metal Clusters in Catalysis and Organic Synthesis), the Swedish Engineering Science Research Council (TER) and the Swedish Natural Science Research Council (NFR) is gratefully acknowledged. 

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