Influence of the hydrogen sulfide partial pressure on the hydrodeoxygenation reactions over sulfided CoMo/Carbon catallysts

摘要

This work concerns the influence of the hydrogen sulfide partial pressure on the activity in hydrodeoxygenation and sssociated eactions of a CoMo/Carbon catalyst for the transformation of guaiacol, ethylecanoate and 4-methylacetophenone. This has been studied over a wide range of hydrogen sulfide partial pressures, from 10 to 150 kPa, under a total pressure of 7 MPa, at reaction temperatures of 270 adn 200degC, An inhibition effect is observed in the hydrogenolysis pathway in guaiacol conversion and in ethyldecanoate dehydroxylation. The conversion of 4-methylacetophenone is also inhibited by hydrogen sulfide. The results have been interpreted on the basis of the existence of different active sites responsible for hydrogenolysis, hydrogenation and acid catalysed reactions. The increase in hydrogen sulfide partial pressure would decrease the average degree of reduction of the active sites and inhibit the hydrogenolysis pathway, more than the hydrogenation one. The results are compared to those observed with alumina supported catalysts in hydrodeoxygenation and hydrodesulfurisation.