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

Moeurs des sauvages ameriquains, compare'es aux moeurs des premiers temps. v. 3

Padre Joseph-François Lafitau pertencia a Companhia de Jesus. v.3 Occupations des hommes dans le village - Ocupations de femmes - De la guerre. No início de cada volume consta explicações das ilustrações. Vinhetas, capitulares ornamentadas, insígnia do impressor. Resumo : Os quatro volumes tratam comparativamente da vida social, religiosa, política e bélica dos índios das Américas, a partir da pesquisa do Jesuíta sobre os índios Iroqueses no Canadá. Originalmente publicado: Paris: Chez Saugrain sênior, CE Hochereau, 1724. Ao final do v. 3 inclui texto de aprovação para impressão. Encadernado em couro, marcas de nervura e ornamento dourado na lombada e brasão do bispado na capa. Ilustrações impressas por método de talho doce (em francês, taille-douce). Inclui etiqueta contracapa anterior: " Du cabinet de monseigneur L'êveque de Meaux" - "M. Louis des Garets". Nota descritiva manuscrita a lápis na folha que antecede a gravura do fronstispício.Hay

Tratado de la virtud [Manuscrito]

Letra del siglo XVII