A hydroprocessing catalyst or catalyst precursor has been developed. The catalyst is a unique crystalline ammonia transition metal molybdotungstate material. The hydroprocessing using the crystalline ammonia transition metal molybdotungstate material or a decomposition product thereof may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

The present invention provides a catalyst carrier with shift and adsorption purification performance, comprising modified bauxite in the raw material components which fluxing and pore forming effects. Most iron oxide contained in the bauxite is removed after modification, so that there are a large amount of highly active aluminosilicate compounds in the modified bauxite. When preparing the catalyst, the aluminosilicate compound serves as a low melting point flux and can significantly increase the migration rate of magnesium and aluminum ions during the calcinating process and promote the generation of MgAl.sub.2O.sub.4 at low temperatures, thereby the catalyst carrier of the present invention has strong anti-hydration capacity and mechanical strength. In addition, when the modified bauxite is used as macroporous hard template for the preparation of the catalyst, macro pores can be formed in the structure of the catalyst carrier after calcinating treatment, so that the catalyst carrier of the present invention has strong adsorption purification ability on macromolecular particles including oil pollution and dust.

A hydroprocessing catalyst or catalyst precursor has been developed. The catalyst is a poorly crystalline transition metal molybdotungstate material or a metal sulfide decomposition product thereof. The hydroprocessing using the crystalline ammonia transition metal molybdotungstate material may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A hydroprocessing catalyst or catalyst precursor has been developed. The catalyst is a transition metal molybdotungstate material or metal sulfides derived therefrom. The hydroprocessing using the transition metal molybdotungstate material may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A hydroprocessing catalyst has been developed. The catalyst is a crystalline transition metal molybdotungstate material. The hydroprocessing using the crystalline ammonia transition metal molybdotungstate material may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

The invention relates to a process for the rejuvenation of an at least partially spent catalyst resulting from a hydrotreating process, said at least partially spent catalyst resulting from a fresh catalyst comprising a metal from group VIII, a metal from group VIb, an oxide support, and optionally phosphorus, said at least partially spent catalyst additionally comprising carbon in a content of between 2% and 20% by weight, with respect to the total weight of the at least partially spent catalyst, and sulfur in a content of between 1% and 8% by weight, with respect to the total weight of the at least partially spent catalyst, said process comprising the following stages: a) said spent catalyst is brought into contact with an impregnation solution containing a compound comprising a metal from group VIb, b) a drying stage is carried out at a temperature of less than 200 C.

The present invention is in the field of heterogeneous catalysis.

Particularly, the present invention relates to a process for preparing catalysts advantageously usable in the hydrotreatment processes, for example in hydrodesulphurization, hydrodenitrogenation, hydrodearomatization processes of hydrocarbons.

More in particular, the present invention relates to a process for obtaining said catalysts, which comprise mixed oxides of Nickel, Aluminum, Molybdenum and Tungsten and optionally a transition metal Me selected from the group consisting of Zn, Mn, Cd, and a mixture thereof, an organic component C, and possibly an inorganic binder B.

Said mixed oxides comprise an amorphous phase and a pseudo-crystalline phase isostructural to Wolframite.

The present invention further relates to said hydrotreatment catalysts and a hydrotreatment process wherein said catalysts are used.

Provided is a method for preparing a diol. In the method, a saccharide and hydrogen as raw materials are contacted with a catalyst in water to prepare the diol. The employed catalyst is a composite catalyst comprised of a main catalyst and a cocatalyst, wherein the main catalyst is a water-insoluble acid-resistant alloy; and the cocatalyst is a soluble tungstate and/or soluble tungsten compound. The method uses an acid-resistant, inexpensive and stable alloy needless of a support as a main catalyst, and can guarantee a high yield of the diol in the case where the production cost is relatively low.

Proposed are an unsupported metallic catalyst for a selective ring-opening (SRO) reaction and a method of using the same catalyst, wherein the catalyst contains nickel (Ni), molybdenum (Mo), and tungsten (W).

Bulk catalysts comprised of nickel, molybdenum, tungsten and titanium and methods for synthesizing bulk catalysts are provided. The catalysts are useful for hydroprocessing, particularly hydrodesulfurization and hydrodenitrogenation, of hydrocarbon feedstocks.