Ru, Os and Ru-Os supported on mesoporous silica doped with zirconium as mild thio-tolerant catalysts in the hydrogenation and hydrogenolysis/hydrocracking of tetralin

Monometallic Ru and Os catalysts and bimetallic Ru-Os catalysts with molar ratios (8:1, 4:1 and 1:1) supported on a mesoporous silica doped with zirconium (molar ratio Si/Zr = 5) with a total metal loading of 5 wt.% were prepared by the wet incipient impregnation method, then dried at 120 °C and finally reduced with hydrogen at 400 °C. After a complete characterisation with XRD, XPS, N2 adsorption-desorption volumetry, H2-TPR and NH3-TPD, the catalysts were tested in the hydrogenation and ring opening of tetralin at high hydrogen pressure. Catalysts with a high Ru content display excellent hydrogenation properties even at low reaction temperatures (200-295 °C). However, catalysts with a high Os content display weak hydrogenation activity but a very good hydrogenolysis/hydrocracking activity (30-40% of cracking compounds). This high level of activity is explained by the strength of the acid centres. Catalysts with a high Ru content maintain their catalytic performance in the presence of 600 ppm of dibenzopthiophene in the feed at 320 °C, but all other catalysts are partially or totally deactivated. All catalysts are irreversibly poisoned with a feed containing 1000 ppm of dibenzothiophene.