Mesoporous molecular sieve MCM-41 supported Co–Mo catalyst for hydrodesulfurization of dibenzothiophene in distillate fuels

Abstract

A mesoporous aluminosilicate molecular sieve with MCM-41 type structure was synthesized using aluminum isopropoxide as the Al source. Supported Co–Mo/MCM-41 catalysts were prepared by co-impregnation of Co(NO 3) 2·6H 2O and (NH 4) 6Mo 7O 24 followed by calcination and sulfidation. For comparison, conventional Al 2O 3-supported sulfided Co–Mo catalysts were also prepared using the same procedure. These two types of catalysts were examined at two different metal loading levels in hydrodesulfurization of a model fuel containing 3.5 wt% sulfur as dibenzothiophene in n-tridecane. At 350–375°C under higher H 2 pressure (6.9 MPa), sulfided Co–Mo/MCM-41 catalysts show higher hydrogenation and hydrocracking activities at both normal and high metal loading levels, whereas Co–Mo/Al 2O 3 catalysts show higher selectivity to desulfurization. Co–Mo/MCM-41 catalyst at high metal loading level is substantially more active than the Co–Mo/Al 2O 3 catalysts.