Hydrogenation of tetralin over zeolite-supported Pd-Pt catalysts in the presence of dibenzothiophene

The sulfur tolerance of Pd-Pt bimetallic catalysts supported on various zeolites was investigated for the hydrogenation of tetralin. The reaction was carried out at a hydrogen pressure of 3.9 MPa at 553 K in the presence of dibenzothiophene at a sulfur concentration of 500 wtppm. The coexistence of Pt with Pd on USY zeolite (SiO2/Al2O3=680) greatly enhanced the tetralin hydrogenation activity and improved the sulfur tolerance, which depended on the Pd/Pt ratio and reached a maximum at a Pd : Pt mole ratio of 4 : 1. The influence of the support material, such as USY zeolite (SiO2/Al2O3=15.0), HY zeolite, HL zeolite, and H-mordenite, on the hydrogenation activity and selectivity and on the sulfur tolerance, was also investigated for the bimetallic Pd-Pt(4 : 1) catalyst. For maximizing the hydrogenation selectivity while minimizing the yield of cracked products and gases, the Pd-Pt(4 : 1) catalyst on USY zeolite (SiO2/Al2O3=680) was more effective than Pd-Pt on the other supports, although its sulfur tolerance was lower.