Abstract: New sulfide metal catalysts are described, containing Ni, Mo and W, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by sulfidation of mixed oxide precursors, also new, characterized in that they comprise an amorphous phase and a wolframite iso structural crystalline phase, the crystallinity degree of said mixed oxides being higher than 0 and lower than 100%, preferably higher than 0 and lower than 70%. The catalysts of the invention are useful as hydrotreatment catalysts, and in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts.

Abstract: New sulfided metal catalysts are described, containing a metal X selected from Ni, Co and mixtures thereof, a metal Y selected from Mo, W and mixtures thereof, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by the sulfidation of mixed oxide precursors, also new, having general formula (A) XaYbZcOd.

Abstract: New sulfide metal catalysts are described, containing Ni, Mo and W, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by sulfidation of mixed oxide precursors, also new, characterized in that they comprise an amorphous phase and a wolframite iso structural crystalline phase, the crystallinity degree of said mixed oxides being higher than 0 and lower than 100%, preferably higher than 0 and lower than 70%. The catalysts of the invention are useful as hydrotreatment catalysts, and in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts.

Abstract: New sulfide metal catalysts are described, containing Ni, Mo and W, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by sulfidation of mixed oxide precursors, also new, characterized in that they comprise an amorphous phase and a wolframite isostructural crystalline phase, the crystallinity degree of said mixed oxides being higher than 0 and lower than 100%, preferably higher than 0 and lower than 70%. The catalysts of the invention are useful as hydrotreatment catalysts, and in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts.

Abstract: New sulfided metal catalysts are described, containing a metal X selected from Ni, Co and mixtures thereof, a metal Y selected from Mo, W and mixtures thereof, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by the sulfidation of mixed oxide precursors, also new, having general formula (A) XaYbZcOd.

Abstract: New sulfide metal catalysts are described, containing Ni, Mo and W, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by sulfidation of mixed oxide precursors, also new, characterized in that they comprise an amorphous phase and a wolframite iso structural crystalline phase, the crystallinity degree of said mixed oxides being higher than 0 and lower than 100%, preferably higher than 0 and lower than 70%. The catalysts of the invention are useful as hydrotreatment catalysts, and in particular as hydrodesulfurization, hydrodenitrogenation and/or hydrodearomatization catalysts.

Abstract: New sulfided metal catalysts are described, containing a metal X selected from Ni, Co and mixtures thereof, a metal Y selected from Mo, W and mixtures thereof, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by the sulfidation of mixed oxide precursors, also new, having general formula (A) XaYbZcOd.

Abstract: Solid superacid catalysts, in the form of spheres or microspheres, consisting of a mixed sulfated oxide of zirconium and of at least one other element selected from those of group 3, group 4, group 5, group 6, group 7, group 8 group 9, group 10, group 11, group 12, group 13, group 14, group 15 and those of the series of lanthanides, alone or combined with each other, are characterized in that they are obtained by means of a sol-gel process comprising the following steps: preparing a zirconium sol, mixed with a thickening agent and optionally with the element or elements selected; adding, only when microspheres are to be obtained, a non-ionic surface-active agent, to the sol; dripping, obtaining spheres, or atomising, obtaining microspheres, the sol into a basic gelation bath; ageing the spheres or microspheres of gel thus obtained; washing the spheres or microspheres with water up to pH=9; and draining them without drying them; impregnating the spheres or microspheres of gel with an aqueous soluti

Abstract: Zirconia ceramic fibers, for catalytic applications, partially stabilized with yttria by means of a particular sol-gel process, are functionalized with a coating, containing zirconia and, optionally, alumina and/or oxides of Cu, Ni, Co, V, Mo, W, Ce, La, Nd and/or noble metals selected from Rh, Pt, Pd, Ru, Au, mainly obtained with a "dip coating" technique.

Abstract: This invention relates to a process for obtaining pure or mixed oxide zirconia spheres, microspheres or washcoats consisting of:preparing a zirconium solution in water at a concentration, formally expressed as ZrO.sub.2, equal or lower than 400 g/l, starting from a basic zirconium carbonate additioned of conc. nitric acid up to a molar ratio ?NO.sub.3.sup.- !/?Zr.sup.4+ ! between 0.8 and 1.1, and eventually preparing one or more solutions of the other oxides when necessary;preparing a sol of zirconium, eventually mixed to other metals, by a thickening agent and, in the case of spheres and microspheres, of a surface active agent too;dripping the sol into an alkaline gelation bath for obtaining gel spheres or microspheres, or sucking the sol into the honeycomb channels in order to obtain the washcoats, with subsequent gelation with gaseous ammonia;ageing the so obtained gel;rinsing with water down to pH=9-10, only in the case of gel spheres or microspheres;drying and calcining.