STRUCTURAL AND CATALYTIC PROPERTIES OF ZEOLITE EMT CONTAINING NIMO SULFIDE

This work examines bifunctional catalysts made of an acidic EMT zeolit e 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 th e solids were characterized in the calcined and sulfided state by mean s of XRD, porosimetry, and TEM coupled with EDX analysis. When the oxi dic NiMo/EMT was sulfided, the zeolite crystals fractured in a few pla nar directions, and the fissures appeared to be filled with MoS2 parti cles promoted with Ni. This is very different to the HY zeolite in whi ch the sulfide slabs were scattered into the mesopores. With both supp orts, however about half of the NiMo is present outside the zeolite as incompletely sulfided particles. The catalytic properties of the sulf ided NiMo/EMT were examined by measuring the conversion of an n-heptan e 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 hydr ogenation varied in accordance with the amount of internal Mo. The int rinsic activity of the internal Mo matched that of a commercial NiMo/A l2O3. 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 interpret ed on the basis of the balance between acidic and hydrogenation functi ons. (C) 1998 Academic Press