Abstract: A method for preparing a ruthenium catalyst, including a step of reducing a ruthenium catalyst precursor by holding the ruthenium catalyst precursor in an aqueous solution containing a metal salt at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less. A method for producing a cycloolefin, including a step of preparing a ruthenium catalyst by the method including a step of reducing a ruthenium catalyst precursor in an aqueous solution containing a metal salt by holding the ruthenium catalyst precursor at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less, and a step of partially hydrogenating a monocyclic aromatic hydrocarbon by use of the ruthenium catalyst obtained.

Abstract: There is provided a method for producing cycloolefin where the nickel which elutes in the liquid-contact portion of the reactor is removed from the reaction system of the partial hydrogenation reaction and cycloolefin can be stably produced from a monocyclic aromatic hydrocarbon over a long term.

Abstract: A method for preparing a ruthenium catalyst, including a step of reducing a ruthenium catalyst precursor by holding the ruthenium catalyst precursor in an aqueous solution containing a metal salt at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less. A method for producing a cycloolefin, including a step of preparing a ruthenium catalyst by the method including a step of reducing a ruthenium catalyst precursor in an aqueous solution containing a metal salt by holding the ruthenium catalyst precursor at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less, and a step of partially hydrogenating a monocyclic aromatic hydrocarbon by use of the ruthenium catalyst obtained.

Abstract: A method for preparing a ruthenium catalyst, including a step of reducing a ruthenium catalyst precursor by holding the ruthenium catalyst precursor in an aqueous solution containing a metal salt at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less. A method for producing a cycloolefin, including a step of preparing a ruthenium catalyst by the method including a step of reducing a ruthenium catalyst precursor in an aqueous solution containing a metal salt by holding the ruthenium catalyst precursor at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less, and a step of partially hydrogenating a monocyclic aromatic hydrocarbon by use of the ruthenium catalyst obtained.

Abstract: A method for preparing a ruthenium catalyst, including a step of reducing a ruthenium catalyst precursor by holding the ruthenium catalyst precursor in an aqueous solution containing a metal salt at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less. A method for producing a cycloolefin, including a step of preparing a ruthenium catalyst by the method including a step of reducing a ruthenium catalyst precursor in an aqueous solution containing a metal salt by holding the ruthenium catalyst precursor at a temperature within the range of more than 180° C. and 220° C. or less and a hydrogen partial pressure within the range of 0.6 MPa or more and 5 MPa or less, and a step of partially hydrogenating a monocyclic aromatic hydrocarbon by use of the ruthenium catalyst obtained.

Abstract: There is provided a method for producing cycloolefin where the nickel which elutes in the liquid-contact portion of the reactor is removed from the reaction system of the partial hydrogenation reaction and cycloolefin can be stably produced from a monocyclic aromatic hydrocarbon over a long term.

Abstract: According to the present invention, when cycloolefins are produced by partially hydrogenating a monocyclic aromatic hydrocarbon with hydrogen in the presence of a ruthenium catalyst, water, and a metal sulfate, the decrease in catalytic activity and cycloolefin selectivity is suppressed by reducing the concentration of chloride ions dissolved in the water in which the catalyst is present to 300 wt ppm or less and regenerating a part or all of the catalyst for reuse. Zinc sulfate is preferably used as the metal sulfate. Further, the raw materials and catalyst to be supplied to the reaction preferably have a reduced chloride ion content. This method can suppress the decrease in long-term catalytic activity and cycloolefin selectivity. Furthermore, the catalytic activity and cycloolefin selectivity after catalyst regeneration can be maintained at a high level. As a result, cycloolefins can be efficiently produced for a long period of time.

Abstract: According to the present invention, when cycloolefins are produced by partially hydrogenating a monocyclic aromatic hydrocarbon with hydrogen in the presence of a ruthenium catalyst, water, and a metal sulfate, the decrease in catalytic activity and cycloolefin selectivity is suppressed by reducing the concentration of chloride ions dissolved in the water in which the catalyst is present to 300 wt ppm or less and regenerating a part or all of the catalyst for reuse. Zinc sulfate is preferably used as the metal sulfate. Further, the raw materials and catalyst to be supplied to the reaction preferably have a reduced chloride ion content. This method can suppress the decrease in long-term catalytic activity and cycloolefin selectivity. Furthermore, the catalytic activity and cycloolefin selectivity after catalyst regeneration can be maintained at a high level. As a result, cycloolefins can be efficiently produced for a long period of time.

Abstract: Disclosed is a polycarbonate diol having diol monomer units and carbonate monomer units, wherein the amount of at least one diol monomer unit selected from the group consisting of a 1,5-pentanediol unit and a 1,6-hexanediol unit is from 50 to 100% by mole, based on the total molar amount of the diol monomer units, and wherein the ratio of primary hydroxyl groups in all terminal groups of the polycarbonate diol is in a specific range. Also disclosed is a thermoplastic polyurethane obtained by copolymerizing the above-mentioned polycarbonate diol and a polyisocyanate.

Abstract: Disclosed is a method for producing a diol mixture comprising 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol, which comprises: (A) providing a dicarboxylic acid mixture comprising succinic acid, glutaric acid and adipic acid and having a nitric acid content of 3% by weight or less, based on the total weight of the succinic, glutaric and adipic acids, wherein the dicarboxylic acid mixture is prepared by denitrating an aqueous by-product solution obtained in an adipic acid production process, and (B) subjecting the dicarboxylic acid mixture to hydrogenation in the presence of water, hydrogen gas and a hydrogenation catalyst containing an active metal species comprising ruthenium and tin, to thereby obtain a hydrogenation reaction mixture comprising a diol mixture comprising 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol.

Abstract: Disclosed is a polycarbonate diol having diol monomer units and carbonate monomer units, wherein the amount of at least one diol monomer unit selected from the group consisting of a 1,5-pentanediol unit and a 1,6-hexanediol unit is from 50 to 100% by mole, based on the total molar amount of the diol monomer units, and wherein the ratio of primary hydroxyl groups in all terminal groups of the polycarbonate diol is in a specific range. Also disclosed is a thermoplastic polyurethane obtained by copolymerizing the above-mentioned polycarbonate diol and a polyisocyanate.

Abstract: Disclosed is a catalyst for hydrogenating a carboxylic acid, comprising an activated carbon having carried thereon an active metal species comprising ruthenium and tin, wherein the activated carbon is produced by subjecting a carbonaceous material to activation treatment using zinc chloride, followed by calcination. Also disclosed is a catalyst for hydrogenating a carboxylic acid, comprising an activated carbon having carried thereon an active metal species comprising ruthenium and tin, wherein the activated carbon, prior to having carried thereon the active metal species, exhibits specific pore characteristics wherein, especially, the pore volume with respect to pores each having a radius of from 10 to 100 Å is from 0.5 to 2.0 cm3/g.

Abstract: Disclosed is an aromatic copolymer comprising a plurality of aromatic copolymer chains, each comprising (A) recurring 2,6-diphenylphenol units and (B) phenolic comonomer units, each comonomer unit being independently selected from the group consisting of (i) an oxyphenylene monomer unit which is monosubstituted with a monovalent aromatic group or a halogen atom, (ii) an &agr;-oxynaphthylene monomer unit, (iii) a &bgr;-oxynaphthylene monomer unit, and (iv) an oxyphenylene monomer unit which is substituted with at least one aliphatic group, wherein the amounts of (A) and (B) are from 50 to 98% by weight and from 2 to 50% by weight, based on the weight of the aromatic copolymer, provided that, when (iv) is present as the comonomer unit, the amount of (iv) is 20% by weight or less, based on the weight of (B), and wherein the aromatic copolymer has a weight average molecular weight of from 1,000 to 3,000,000. A method for producing the aromatic copolymer is also disclosed.

Abstract: A process for producing a cycloolefin in high selectivity and yield by partial hydrogenation of a monocyclic armoatic hydrocarbon with hydrogen is disclosed. In this process, the hydrogenation reaction is carried out under a neutral or acidic condition in the presence of:(i) a particulate hydrogenating catalyst mainly comprising metallic ruthenium having an average crystallite size of 200 .ANG. or less,(ii) at least one zinc compound as a promoter,(iii) at least one additive selected from the group consisting of oxides, hydroxides and hydrates thereof Zr, Hf, Ti, Nb, Ta, Cr, Fe, Co, Al, Ga and Si, and(iv) water.