A process for the hydrogenation of a polyunsaturated compound contained in a hydrocarbon feedstock in the presence of a catalyst comprising a porous support and an active phase comprising a group VIII metal, said catalyst being prepared according to the following steps: a) an organic compound containing oxygen and/or nitrogen, but not comprising sulfur, is added to the porous support; b) said porous support is brought into contact with a solution containing a salt of a precursor of the active phase; c) the porous support obtained at the end of step b) is dried;
characterized in that step a) is carried out before or after steps b) and c) and is carried out by bringing together said porous support and said organic compound under conditions of temperature, pressure and duration such that a fraction of said organic compound is transferred in the gaseous state to the porous support.

A process for the hydrogenation of a polyunsaturated compound contained in a hydrocarbon feedstock in the presence of a catalyst comprising a porous support and an active phase comprising a group VIII metal, said catalyst being prepared according to the following steps: a) an organic compound containing oxygen and/or nitrogen, but not comprising sulfur, is added to the porous support; b) said porous support is brought into contact with a solution containing a salt of a precursor of the active phase; c) the porous support obtained at the end of step b) is dried;
characterized in that step a) is carried out before or after steps b) and c) and is carried out by bringing together said porous support and said organic compound under conditions of temperature, pressure and duration such that a fraction of said organic compound is transferred in the gaseous state to the porous support.

A reaction device for reacting a liquid-phase reactant and a gas-phase reactant converted into fine bubbles includes: a porous body that includes a plurality of flow paths and in which the flow paths are separated by porous walls, the porous walls include continuous pores, and the porous body includes a reaction catalyst at least on the surface thereof; a solution supply section for supplying a solution containing a gas-phase reactant and a liquid-phase reactant to the continuous pores in the porous body; and a solution discharge section for discharging solution containing a reaction product obtained when the solution flows through the continuous pores of the porous body.

A reaction device for reacting a liquid-phase reactant and a gas-phase reactant converted into fine bubbles includes: a porous body that includes a plurality of flow paths and in which the flow paths are separated by porous walls, the porous walls include continuous pores, and the porous body includes a reaction catalyst at least on the surface thereof; a solution supply section for supplying a solution containing a gas-phase reactant and a liquid-phase reactant to the continuous pores in the porous body; and a solution discharge section for discharging solution containing a reaction product obtained when the solution flows through the continuous pores of the porous body.

A process for hydrogenation of an aromatic hydrocarbon including introducing a hydrocarbon feed comprising the aromatic hydrocarbon, a hydrogen feed comprising hydrogen, and a hydrogenation catalyst into a hydrogenation reactor operable with a liquid phase and a gas phase to produce a hydrogenation product; removing a gas phase product stream comprising the hydrogenation product; withdrawing a portion of the liquid phase; subjecting the withdrawn portion to heat exchange to provide a reduced-temperature withdrawn portion; introducing the reduced-temperature withdrawn portion back into the hydrogenation reactor; and at least one of: (a) providing at least two heat exchangers to effect the subjecting of the withdrawn portion of the liquid phase to heat exchange; (b) separating a decomposition product of the hydrogenation catalyst, the hydrogenation catalyst, or both, from the withdrawn portion of the liquid phase prior to the heat exchange; and (c) reducing exposure of the hydrogenation catalyst to an oxygen-containing species.

A process for hydrogenation of an aromatic hydrocarbon including introducing a hydrocarbon feed comprising the aromatic hydrocarbon, a hydrogen feed comprising hydrogen, and a hydrogenation catalyst into a hydrogenation reactor operable with a liquid phase and a gas phase to produce a hydrogenation product; removing a gas phase product stream comprising the hydrogenation product; withdrawing a portion of the liquid phase; subjecting the withdrawn portion to heat exchange to provide a reduced-temperature withdrawn portion; introducing the reduced-temperature withdrawn portion back into the hydrogenation reactor; and at least one of: (a) providing at least two heat exchangers to effect the subjecting of the withdrawn portion of the liquid phase to heat exchange; (b) separating a decomposition product of the hydrogenation catalyst, the hydrogenation catalyst, or both, from the withdrawn portion of the liquid phase prior to the heat exchange; and (c) reducing exposure of the hydrogenation catalyst to an oxygen-containing species.

A process for hydrogenation of an aromatic hydrocarbon including introducing a hydrocarbon feed comprising the aromatic hydrocarbon, a hydrogen feed comprising hydrogen, and a hydrogenation catalyst into a hydrogenation reactor operable with a liquid phase and a gas phase to produce a hydrogenation product; removing a gas phase product stream comprising the hydrogenation product; withdrawing a portion of the liquid phase; subjecting the withdrawn portion to heat exchange to provide a reduced-temperature withdrawn portion; introducing the reduced-temperature withdrawn portion back into the hydrogenation reactor; and at least one of: (a) providing at least two heat exchangers to effect the subjecting of the withdrawn portion of the liquid phase to heat exchange; (b) separating a decomposition product of the hydrogenation catalyst, the hydrogenation catalyst, or both, from the withdrawn portion of the liquid phase prior to the heat exchange; and (c) reducing exposure of the hydrogenation catalyst to an oxygen-containing species.

A method for preparing hexadecahydropyrene includes the step of carrying out the hydrogenation reaction to hydrocarbon oil containing pyrene compounds in the presence of a hydrogenation catalyst. The pyrene compounds are selected from at least one of pyrene and unsaturated hydrogenation products thereof. The hydrogenation catalyst contains a carrier and an active metal component loaded on the carrier. The active metal component is Pt and/or Pd and the carrier contains a small crystal size Y zeolite, alumina and amorphous silica-alumina. The small crystal size Y zeolite has an average grain diameter of 200-700 nm, a molar ratio of SiO.sub.2 to Al.sub.2O.sub.3 of 40-120, a relative crystallinity of ≥95%, and a specific surface area of 900-1,200 m.sup.2/g. The pore volume of secondary pores in 1.7-10 nm diameter is more than 50% of the total pore volume.

A method for preparing hexadecahydropyrene includes the step of carrying out the hydrogenation reaction to hydrocarbon oil containing pyrene compounds in the presence of a hydrogenation catalyst. The pyrene compounds are selected from at least one of pyrene and unsaturated hydrogenation products thereof. The hydrogenation catalyst contains a carrier and an active metal component loaded on the carrier. The active metal component is Pt and/or Pd and the carrier contains a small crystal size Y zeolite, alumina and amorphous silica-alumina. The small crystal size Y zeolite has an average grain diameter of 200-700 nm, a molar ratio of SiO.sub.2 to Al.sub.2O.sub.3 of 40-120, a relative crystallinity of ≥95%, and a specific surface area of 900-1,200 m.sup.2/g. The pore volume of secondary pores in 1.7-10 nm diameter is more than 50% of the total pore volume.

Processes are described for separating 3,4- and 4,4-dimethylbiphenyl from a mixture comprising at least 3,3-, 3,4- and 4,4-dimethylbiphenyl. In the processes, the mixture is cooled to produce a crystallization product comprising at least of the 4,4-dimethylbiphenyl from the feed mixture and a first mother liquor product. The first mother liquor product is distilled to produce a bottoms stream enriched in 4,4-dimethylbiphenyl as compared with the first mother liquor product and an overhead stream deficient in 4,4-dimethylbiphenyl as compared with the first mother liquor product. The overhead stream is then cooled to produce a second crystallization product comprising at least part of the 3,4-dimethylbiphenyl from the overhead stream and a second mother liquor product.