Characterization and Hydrodesulfurization Activity of CoMo Catalysts Supported on Boron-Doped Sol-Gel Alumina

Franck Dumeignil (1, 2) , Koichi Sato (2) , Motoyasu Imamura (2) , Nobuyuki Matsubayashi (2) , Edmond Payen (1) , Hiromichi Shimada (2)

1 UCCS - Unité de Catalyse et Chimie du Solide - UMR 8181
2 NIMC - National Institute of Materials and Chemical Research

A series of hydrodesulfurization (HDS) catalysts was prepared by impregnation of Co and Mo on sol-gel B-Al2O3 supports with B/Al ratios of 0, 0.02, 0.04, 0.08, 0.20, 0.32, 0.49, and 0.61. The thiophene HDS and dibenzothiophene (DBT) HDS activities were both maximal for the catalyst with B/Al = 0.04, with respective values 70% and 42% higher than those for an industrial reference catalyst. These maxima in HDS activity correlated with the previously reported presence of isolated BO4 surface species. These BO4 species were responsible for a local maximum in the acidity of the B-Al2O3 supports when B/Al = 0.04. In contrast, the formation of mixed oxides (A9B2 and A2B) or B2O3 that also resulted in enhanced acidity of the B-Al2O3 supports had a detrimental effect on the HDS activity. The 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS activity over the CoMo/B-Al2O3 catalysts decreased when the B/Al ratio was increased. This was attributed to the strong direct desulfurization character of the CoMo catalysts supported on the B-Al2O3 supports, because high hydrogenation ability toward the C=C double bonds is essential prior to sulfur removal from 4,6-DMDBT. The excellent performance in the thiophene and DBT HDS of the CoMo/B-Al2O3 catalysts is particularly useful for ultra-deep HDS of light fractions.

Mots clés: Hydrodesulfurization; boron; alumina; sol-gel; thiophene; DBT; 6-DMDBT; acidity

Domaines: Catalyse

Franck Dumeignil, Koichi Sato, Motoyasu Imamura, Nobuyuki Matsubayashi, Edmond Payen, et al.. Characterization and Hydrodesulfurization Activity of CoMo Catalysts Supported on Boron-Doped Sol-Gel Alumina. Applied Catalysis A : General, 2006, 315, pp.18-28. ⟨10.1016/j.apcata.2006.08.034⟩. ⟨hal-00098391⟩