HYDRODESULFURATION OF THIOPHENE ON ULTRAS TABLE ZEOLITE-Y CATALYSTS -THE INFLUENCE OF THE IMPREGNATION MEDIUM

For ultrastable zeolite Y (USY) supported tungsten sulfide catalysts, the influence of the preparation medium (NaOH or NH4OH) on the hydrode sulfuration (HDS) of thiophene is examined. The impregnation of USY wi th aqueous solutions of ammonium metatungtate at pH 11 adjusted with a NaOH solution results in catalyst non acidic and practically without HDS activity. However, similar preparations in ammonia medium leads to catalysts with high acidity and initially active for tiophene HDS, bu t which deactivate strongly. Comparison of these results with those fo r tungsten-free similarly treated-zeolites reveals that the thiophene HDS activity is due to both the zeolite acid sites and the tungsten su lfide into and/or supported on the zeolite.