Journal of Catalysis, Vol.179, No.1, 90-99, 1998
Structural and catalytic properties of zeolite EMT containing NiMo sulfide
This work examines bifunctional catalysts made of an acidic EMT zeolite into which Ni and Mo ions were introduced, and then sulfided. Their structure and catalytic properties were compared to those of analogous NiMo/HY. Ni and Mo were loaded onto the HEMT by wet treatment, and the solids were characterized in the calcined and sulfided state by means of XRD, porosimetry, and TEM coupled with EDX analysis. When the oxidic NiMo/EMT was sulfided, the zeolite crystals fractured in a few planar directions, and the fissures appeared to be filled with MoS2 particles promoted with Ni. This is very different to the HY zeolite in which the sulfide slabs were scattered into the mesopores. With both supports, however about half of the NiMo is present outside the zeolite as incompletely sulfided particles. The catalytic properties of the sulfided NiMo/EMT were examined by measuring the conversion of an n-heptane and benzene mixture in a flow reactor under 8 MPa hydrogen pressure. With the EMT as well as with the HY support, the rate of benzene hydrogenation varied in accordance with the amount of internal Mo. The intrinsic activity of the internal Mo matched that of a commercial NiMo/Al2O3. The NiMo/zeolites exhibited high activity for the conversion of heptane, but the cracked products exceeded by far the heptane isomers. Differences in selectivity between EMT and HY catalysts are interpreted on the basis of the balance between acidic and hydrogenation functions.
Keywords:METAL SULFIDE, HEXAGONAL FAUJASITES, CROWN-ETHERS;HYDROCRACKING, LOCATION, FAU, TEMPLATES, ACIDITY, PHASES, NAEMT