Synthesizing an alkane includes heating a mixture including an alkene and water at or above the water vapor saturation pressure in the presence of a catalyst and one or both of hydrogen and a reductant, thereby hydrogenating the alkene to yield an alkane and water, and separating the alkane from the water to yield the alkane. The reductant includes a first metal and the catalyst includes a second metal.

A process for the preparation of a catalyst from a catalytic precursor comprising a support based on alumina and/or silica-alumina and/or zeolite and comprising at least one element of group VIB and optionally at least one element of group VIII, by impregnation of said precursor with a solution of a C1-C4 dialkyl succinate. An impregnation step for impregnation of said precursor which is dried, calcined or regenerated, with at least one solution containing at least one carboxylic acid other than acetic acid, then maturing and drying at a temperature less than or equal to 200° C., optionally a heat treatment at a temperature lower than 350° C., followed by an impregnation step with a solution containing at least one C1-C4 dialkyl succinate followed by maturing and drying at a temperature less than 200° C. without subsequent calcination step. The catalyst is used in hydrotreatment and/or hydroconversion.

A process for the preparation of a catalyst from a catalytic precursor comprising a support based on alumina and/or silica-alumina and/or zeolite and comprising at least one element of group VIB and optionally at least one element of group VIII, by impregnation of said precursor with a solution of a C1-C4 dialkyl succinate. An impregnation step for impregnation of said precursor which is dried, calcined or regenerated, with at least one solution containing at least one carboxylic acid other than acetic acid, then maturing and drying at a temperature less than or equal to 200° C., optionally a heat treatment at a temperature lower than 350° C., followed by an impregnation step with a solution containing at least one C1-C4 dialkyl succinate followed by maturing and drying at a temperature less than 200° C. without subsequent calcination step. The catalyst is used in hydrotreatment and/or hydroconversion.

A carbon-coated transition metal nanocomposite material includes carbon-coated transition metal particles having a core-shell structure. The shell layer of the core-shell structure is a graphitized carbon layer doped with oxygen and/or nitrogen, and the core of the core-shell structure is a transition metal nanoparticle. The nanocomposite material has a structure rich in mesopores, is an adsorption/catalyst material with excellent performance, can be used for catalyzing various hydrogenation reduction reactions, or used as a catalytic-oxidation catalyst useful for the treatment of volatile organic compounds in industrial exhaust gases.

A carbon-coated transition metal nanocomposite material includes carbon-coated transition metal particles having a core-shell structure. The shell layer of the core-shell structure is a graphitized carbon layer doped with oxygen and/or nitrogen, and the core of the core-shell structure is a transition metal nanoparticle. The nanocomposite material has a structure rich in mesopores, is an adsorption/catalyst material with excellent performance, can be used for catalyzing various hydrogenation reduction reactions, or used as a catalytic-oxidation catalyst useful for the treatment of volatile organic compounds in industrial exhaust gases.

A process for preparing a selective hydrogenation catalyst comprising nickel, copper and a support comprising at least one refractory oxide, comprising the following steps: bringing the support into contact with a solution containing at least one copper precursor and one nickel precursor; drying the catalyst precursor at a temperature of less than 250° C.; reducing the catalyst precursor by bringing said precursor into contact with a reducing gas at a temperature of between 150° C. and 250° C.; bringing the catalyst precursor into contact with a solution comprising a nickel precursor; a step of drying the catalyst precursor at a temperature of less than 250° C.; reducing the catalyst precursor by bringing said precursor into contact with a reducing gas at a temperature of between 150° C. and 250° C.

A process for preparing a selective hydrogenation catalyst comprising nickel, copper and a support comprising at least one refractory oxide, comprising the following steps: bringing the support into contact with a solution containing at least one copper precursor and one nickel precursor; drying the catalyst precursor at a temperature of less than 250° C.; reducing the catalyst precursor by bringing said precursor into contact with a reducing gas at a temperature of between 150° C. and 250° C.; bringing the catalyst precursor into contact with a solution comprising a nickel precursor; a step of drying the catalyst precursor at a temperature of less than 250° C.; reducing the catalyst precursor by bringing said precursor into contact with a reducing gas at a temperature of between 150° C. and 250° C.

Catalyst comprising a nickel-based active phase and an alumina support, characterized in that: the nickel is distributed both on a crust at the periphery of the support, and in the core of the support, the thickness of said crust being between 2% and 15% of the diameter of the catalyst; the nickel density ratio between the crust and the core is strictly greater than 3; said crust comprises between 40% and 80% by weight of nickel element relative to the total weight of nickel contained in the catalyst.

Catalyst comprising a nickel-based active phase and an alumina support, characterized in that: the nickel is distributed both on a crust at the periphery of the support, and in the core of the support, the thickness of said crust being between 2% and 15% of the diameter of the catalyst; the nickel density ratio between the crust and the core is strictly greater than 3; said crust comprises between 40% and 80% by weight of nickel element relative to the total weight of nickel contained in the catalyst.

A process for preparing a catalyst for the hydrogenation of aromatic or polyaromatic compounds comprising nickel, copper and a support comprising at least one refractory oxide, comprising the following steps: bringing the support into contact with a solution containing at least one copper precursor and one nickel precursor; drying the catalyst precursor at a temperature of less than 250° C.; reducing the catalyst precursor by bringing said precursor into contact with a reducing gas at a temperature of between 150° C. and 250° C.; bringing the catalyst precursor into contact with a solution comprising a nickel precursor; a step of drying the catalyst precursor at a temperature of less than 250° C.; reducing the catalyst precursor by bringing said precursor into contact with a reducing gas at a temperature of between 150° C. and 250° C.