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

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

Depicting a scene from the Apocalypse

Illustration taken from Lafitau, P (1724). "Moeurs des sauvages americains, comparees aux moeurs des premiers temps". Volume 1. Page 250. Paris

Marriage ceremonies

Illustration taken from Lafitau, P (1724). "Moeurs des sauvages americains, comparees aux moeurs des premiers temps". Volume 1. Page 572. Paris

Tratado de la virtud [Manuscrito]

Letra del siglo XVII

The final initiation of a Carib soothsayer

Illustration taken from Lafitau, P (1724). "Moeurs des sauvages americains, comparees aux moeurs des premiers temps". Volume 1. Page 344. Paris

The cult of Vesta or the sacred flame - temple of Natchez in Louisiana

Illustration taken from Lafitau, P (1724). "Moeurs des sauvages americains, comparees aux moeurs des premiers temps". Volume 1. Page 167. Paris

Hercules killing a monster, half-man and half-serpent

Illustration taken from Lafitau, P (1724). "Moeurs des sauvages americains, comparees aux moeurs des premiers temps". Volume 1. Page 233. Paris

Circe with the enchantress's cup; the tree of the Garden of Hesperides; Hercules leading a chained Cerberus

Illustration taken from Lafitau, P (1724). "Moeurs des sauvages americains, comparees aux moeurs des premiers temps". Volume 1. Page 233. Paris