PERFORMANCE AND POSTREACTION CHARACTERIZATION OF GAMMA-MO2N CATALYSTSIN SIMULTANEOUS HYDRODESULFURIZATION AND HYDRODENITROGENATION REACTIONS

An unsupported gamma-Mo2N catalyst was prepared to perform simultaneou s HDS of benzothiophene and HDN of indole, as well as HDS in the prese nce/absence of NH3 and HDN in the presence/absence of H2S. Pre- and po streaction catalysts were characterized using XPS, TPD, TPR, XRD, and BET techniques. While ethylbenzene was the only major hydrocarbon prod uct from benzothiophene I-IDS throughout the temperature range tested (200-380 degrees C), C6C8 alkylbenzenes and alkylcyclohexaness were ob served from indole HDN. The presence of sulfur compounds changed the p roducts of indole HDN from primarily aromatics to cyclohexanes. In the presence of sulfur compounds, the product distribution from indole re action over the Mo nitride catalysts was similar to that over a sulfid ed Mo/gamma-Al2O3 catalyst. Postreaction XPS measurements showed a pro nounced decrease in N content and the presence of MoS2 over the Mo nit ride surface. The findings of this stud. suggest that the bulk of the postreaction Mo nitride catalyst was still in the Mo2N structure and t hat it acted as a support for the MoS2 phase, which in turn, controlle d the catalytic performance. (C) 1997 Academic Press.