Hydrodesulfurization of dibenzothiophene over Mo-based dispersed catalysts

The hydrodesulfurization (HDS), hydrocracking (HC) activity and selectivity of several Mo, Co and Fe-based catalyst precursors have been examined in model compound reactions of dibenzothiophene (DBT). Reactions were carried out at 400{degrees}C with 6.9 MPa of H{sub 2} for 30 min. A metal loading of 0.5 mol % (based on DBT) in tridecane as solvent resulted in a low conversion rate and only hydrogenation products. Even the addition of sulfur to the catalyst in a 4:1 molar ratio only led to a minor increase in conversion and HDS. However, a change in the molar ratio of solvent to model compound from 1:1 to 19:1 and a metal loading of 36.16 mol % lead to a dramatic increase in conversion, HDS, and HC. Furthermore, the use of higher boiling point solvents such as hexadecane and octadecane had a beneficial effect on both HDS and HC. The addition of sulfur in a 6:1 ratio of S: metal to the higher-metal-loaded runs had varying effects that were dependent upon the catalyst used.