Abstract: The invention describes a heteropolycompound constituted by a nickel salt of a lacunary Keggin type heteropolyanion comprising tungsten in its structure, with formula: Nix+y/2AW11-yO39-5/2y, zH2O wherein Ni is nickel, A is selected from phosphorus, silicon and boron, W is tungsten, O is oxygen, y=0 or 2, x=3.5 if A is phosphorus, x=4 if A is silicon, x=4.5 if A is boron, and x=m/2+2 for the rest, and z is a number in the range 0 to 36, in which said heteropolycompound has no nickel atom in substitution for a tungsten atom in its structure, said nickel atoms being placed in the counter-ion position in the structure of said compound.

Abstract: A process for preparing a mesoporous alumina is described, comprising the following steps: a) mixing, in aqueous solution, at least one source of aluminum constituted by an aluminum alkoxide, at least one cationic surfactant and at least one organic solvent selected from methanol and ethanol; b) hydrothermally treating the mixture formed in said step a); c) drying the solid formed in said step b); d) calcining the solid formed in said step c).

Abstract: A process for preparing a mesoporous alumina is described, comprising the following steps: a) mixing, in aqueous solution, at least one source of aluminium constituted by an aluminium alkoxide, at least one cationic surfactant and at least one organic solvent selected from methanol and ethanol; b) hydrothermally treating the mixture formed in said step a); c) drying the solid formed in said step b); d) calcining the solid formed in said step c).

Abstract: The invention describes a heteropolycompound constituted by a nickel salt of a lacunary Keggin type heteropolyanion comprising tungsten in its structure, with formula: Nix+y/2AW11-yO39-5/2y,zH2O wherein Ni is nickel, A is selected from phosphorus, silicon and boron, W is tungsten, O is oxygen, y=0 or 2, x=3.5 if A is phosphorus, x=4 if A is silicon, x=4.5 if A is boron, and x=m/2+2 for the rest, and z is a number in the range 0 to 36, in which said heteropolycompound has no nickel atom in substitution for a tungsten atom in its structure, said nickel atoms being placed in the counter-ion position in the structure of said compound.

Abstract: A process is described for preparing a solution formed by at least one cobalt and/or nickel salt of at least one heteropolyanion combining molybdenum and cobalt or molybdenum and nickel in its structure, said process comprising: a) mixing at least one source of molybdenum and at least one oxidizing compound in aqueous solution to synthesize peroxomolybdate ions at an acidic pH, the (oxidizing compound/molybdenum source) mole ratio being in the range 0.1 to 20; b) introducing at least one cobalt precursor and/or at least one nickel precursor into the solution from step a) to form a solution comprising at least said salt in which the (Co+Ni)/Mo mole ratio is in the range 0.25 to 0.85.

Abstract: A process is described for preparing a solution formed by at least one cobalt and/or nickel salt of at least one heteropolyanion combining molybdenum and cobalt or molybdenum and nickel in its structure, said process comprising: a) mixing at least one source of molybdenum and at least one oxidizing compound in aqueous solution to synthesize peroxomolybdate ions at an acidic pH, the (oxidizing compound/molybdenum source) mole ratio being in the range 0.1 to 20; b) introducing at least one cobalt precursor and/or at least one nickel precursor into the solution from step a) to form a solution comprising at least said salt in which the (Co+Ni)/Mo mole ratio is in the range 0.25 to 0.85.

Abstract: A catalyst contains at least one group VIII element and at least molybdenum and/or tungsten, said elements being present at least in part in the catalyst in the dry state in the form of at least one heteropolyanion with formula MxAB6O24H6C(3-2x), tH2O; MxAB6O24H6C(4-2x), tH2O; MxA2B10O38H4C(6-2x), tH2O; MxA2B10O38H4C(8-2x), tH2O; or MxA2B10O38H4C(7-2x), tH2O, in which M is cobalt and/or nickel and/or iron and/or copper and/or zinc, A is one or two elements from group VIII of the periodic table, B is molybdenum and/or tungsten and C is an H+ ion and/or a (NR1R2R3R4)+ type ammonium ion, in which R1, R2, R3 and R4, which may be identical or different, correspond either to a hydrogen atom or to an alkyl group and/or caesium and/or potassium and/or sodium, t is a number between 0 and 15 and x takes a value in the range 0 to 4 depending on the formula.

Abstract: The invention relates to a selective desulphurisation method for thiophene derivatives contained in the hydrocarbons emitted from the distillation of crude oil, refined or not, consisting in oxidising the atoms of thiophene sulphur in sulphone in the presence of an oxidising agent and separating the sulphonated compounds from said hydrocarbons. This inventive method comprises at least one first stage involving the oxidation/absorption by heterogeneous catalysis of the sulphurous compounds in an organic environment, at a temperature of at least 40?C, at atmospheric pressure in the presence of an organic oxidiser from the family of peroxides and peracids, in the presence of a catalyst having a specific surface area greater than 100 m2/g and a porosity varying from 0.2 to 4 ml/g, and a second stage wherein the used catalyst is regenerated.

Abstract: A catalyst contains at least one group VIII element and at least molybdenum and/or tungsten, said elements being present at least in part in the catalyst in the dry state in the form of at least one heteropolyanion with formula MxAB6O24H6C(3-2x), tH2O; MxAB6O24H6C(4-2x), tH2O; MxA2B10O38H4C(6-2x), tH2O; MxA2B10O38H4C(8-2x), tH2O; or MxA2B10O38H4C(7-2x), tH2O, in which M is cobalt and/or nickel and/or iron and/or copper and/or zinc, A is one or two elements from group VIII of the periodic table, B is molybdenum and/or tungsten and C is an H+ ion and/or a (NR1R2R3R4)+ type ammonium ion, in which R1, R2, R3 and R4, which may be identical or different, correspond either to a hydrogen atom or to an alkyl group and/or caesium and/or potassium and/or sodium, t is a number between 0 and 15 and x takes a value in the range 0 to 4 depending on the formula.

Abstract: The invention provides a method for preparing catalysts, containing metals of groups VI and VIII on a carrier. The metals of groups VI and VIII metals are introduced in the form of a compound of formula M.sub.x A B.sub.12 O.sub.40 in which M is cobalt and/or nickel, A is phosphorus, silicon and/or boron, B is molybdenum and/or tungsten and x is 2 or more, 2.5 or more, or 3 or more depending on whether A is respectively phosphorus, silicon or boron. The catalysts thus obtained are useful for hydro-treating hydrocarbon feedstocks.