Hydrogenation of tetralin over a sulfided ruthenium on Y zeolite catalyst : Comparison with a sulfided NiMo on alumina catalyst.

Hydrogenation of tetralin at 300 degrees C, under hydrogen pressure, and in the presence of hydrogen sulfide was used to modelize the hydrogenation of aromatics in gasoils. The activity for this reaction of a sulfided ruthenium on dealuminated Y zeolite catalyst (RuKYd) was found to be much higher than that of a sulfided NiMo on alumina. Moreover, the activity of the RuKYd catalyst was dependent very much on the sulfidation method : owing to a very significant carbon deposition initiated by the zeolite acid sites, the catalyst sulfided by dimethyldisulfide in solution in n-heptane was less active than when sulfided by a H2S/H-2 mixture. This effect was not observed in the case of the NiMo/alumina catalyst, which is not acidic. On the other hand, whatever the catalyst, the presence of n-heptane as a solvent during the hydrogenation test decreased significantly the conversion of tetralin. This was due to the competitive adsorptions between the two molecules.