884 results about "Asymmetric hydrogenation" patented technology

The present invention provides an improved process for the hydrogenation of 3-hydroxypropanal to 1,3-propanediol which comprises purifying an aqueous solution of 3-hydroxypropanal by contacting said aqueous solution with a purifying agent prior to hydrogenation.

The invention discloses a making method of aminophenol with substituted group through hydrogenating nitrophenol with substituted group, which adopts Ni-A/X typed loaded catalyst, wherein A is one of Co, Mn, Cu, Cr, Mo, Ca, Zn, Fe and W; the carrier X is one of their composition of zeolite molecular sieve, Al2O3, SiO2, TiO2, MgO, active charcoal or amorphic aluminium silicate; the mass percentage of Ni in the catalyst is 2-45% and the mass percentage of component A is 1-40%.

This invention provides a method of making (S)-(+)-3-(aminomethyl)-5-methylhexanoic acid (pregabalin) or a salt thereof via an asymmetric hydrogenation synthesis. Pregabalin is useful for the treatment and prevention of seizure disorders, pain, and psychotic disorders. The invention also provides intermediates useful in the production of pregabalin.

A process for the catalytic hydrogenation of an organic compound, in particular a labile organic compound, in the presence of a support catalyst with a coating containing ruthenium as active metal and a total of 1.01 to 30 wt. % of active metals. Higher stereoselectivity and a greater catalyst shelf life may be obtained by using a support catalyst of which the oxide, carbide, nitride or siliceous support material has a BET (N2) surface area smaller than 10 m2/g, particularly preferably 0.1 to 5 m2/g, prior to loading with at least one active metal diatomaceous earth with a BET (N2) surface area greater than 2 m2/g is excluded and the ruthenium content thereof makes up at least 50 wt. %, preferably at least 99 wt. % of the active metals. The process and the catalysts are particularly suitable for the hydrogenation of polyfunctional compounds such as hydroxycarbonyl compounds and aromatic amines.

The invention discloses a method for synthesizing gamma-valerolactone based on catalytic hydrogenation. According to the method, levulinic acid or levulinate derivatives in a reaction solvent is/are subject to catalytic hydrogenation for 1-10 hours by adding hydrogen gas and keeping the hydrogen gas pressure at 0.5-5.0 MPa under the action of a supported cobalt catalyst and the temperature of 50-240 DEG C, and the reaction liquid is treated to obtain the gamma-valerolactone. The cobalt catalyst prepared according to the method has excellent catalytic activity and selectivity, the conversion rate of levulinic acid or levulinate is 100 percent, the yield of the gamma-valerolactone reaches up to 99 percent above; and the method has a simple operation technology, and is low in cost, safe and environment-friendly.

The invention relates to a platinum/carbon nanotube catalyst suitable for multiphase asymmetric hydrogenation reaction. Platinum is loaded on a carbon nanotube carrier. A preparation method comprises the following steps of: heating a purified carbon nanotube in nitric acid, washing, filtering, washing by using water until the pH value of filtrate is neutral, drying to obtain the carbon nanotube carrier, soaking in aqueous solution of chloroplatinic acid, and performing ultrasonic treatment at room temperature; and stirring and impregnating a mixture of the carbon nanotube and the aqueous solution of chloroplatinic acid, raising the temperature to 110 DEG C from room temperature, drying at the temperature of 110 DEG C, grinding into fine powder, reducing by using aqueous solution of sodiumformate with heating, filtering, washing by using deionized water and drying. The invention also provides the preparation method of the catalyst and application of the catalyst to the multiphase asymmetric hydrogenation reaction.

The present invention relates to a catalyst for preparing arylamine by utilizing catalytic hydrogenation of nitrobenzene compound and its application method, belonging to the field of catalytic synthesis technology in application chemistry. Said catalyst is formed from carrier and active component, its carrier can be metal oxide; carbon materials of active carbon, carbon nano tube and porous carbon, etc.; micropore molecular sieve with different compositions or silica-base material into which one or several kinds of hetero-atoms are added, also can be organic high-molecular polymer. The active component can be double-component (multicomponent) metal formed from metal silver and gold or silver gold and palladium, platinum and copper, etc. in which the weight percentage of active metal component and carrie.r is 0.5-30%.

The invention provides a method of improving poor diesel. Said method is made up of two technique: quanlity-improving through hydrogenation and solvent extraction. Poor diesel raw material is treated through quality-improving hydrogenation catalysis bed to strip sulfur, nitrogen and aromatic hydrocarbons, then the final liquid product is extracted through solvent oil to make sure that most of the aromatic hydrocarbons are extracted and get clean diesel products which is low in sulfur, nitrogen and aromatic hydrocarbons, but high in cetane ratio, and the extracted aromatic hydrocarbons are circulated to catalysis bed. Group techniques in said invention could deeply decrease the content of sulfur, nitrogen and aromatic hydrogenation in diesel, increase the cetane ratio at the same time through making full use of their own features, therefore, making the quality of the production meet the need of fuel specification and environmental legislation, also maintain a higher diesel rate.

A method for preparing an enantiomeric chromane, by asymmetrically hydrogenating a chromene compound in the presence of an Ir catalyst having a chiral ligand. The method includes the enantioselective preparation of enantiomeric equol. A preferred Ir catalyst has a chiral phosphineoxazoline ligand. Enantiomeric chromanes of high stereoselective purity can be obtained.

The present invention relates to an improved process for preparing chiral N-substituted N-methyl-3-hydroxy-3-(2-thienyl)-propylamine on an industrial scale using an asymmetric hydrogenation as a key step and optionally a special sequence of subsequent steps, using a catalyst system consisting of rhodium and (2R, 4R)-4-(dicyclohexylphosphino)-2-(diphenyl-phosphino-methyl)-N-methyl-aminocarbonyl-pyrrolidine.

A method for preparing diaminonaphthalene by catalytic hydrogenation of dinitronaphthalene relates to a preparation technology of the diaminonaphthalene, which comprises the following steps: adding a palladium catalyst comprising active components and a carrier and adding the dinitronaphthalene and solvent to a stainless steel high-pressure reactor with an agitator, closing the reactor, replacing air in the reactor with nitrogen for at least three times and then replacing the nitrogen in the reactor with hydrogen for at least three times, and then filling the hydrogen in the reactor so that the reaction pressure in the reactor reaches 0.4-4.0MPa, heating the reactor so that the reaction temperature reaches 30-150 DEG C so as to carry out catalytic hydrogenation to prepare the diaminonaphthalene. The method adopts the hydrogenation reaction technology in the stainless steel high-pressure reactor with the agitator; a catalyst carrier is pretreated to improve the activity of the catalyst and reduce the consumption of the catalyst. By optimizing the technological conditions, the rate of conversion from the dinitronaphthalene to the diaminonaphthalene is effectively improved and high selectivity of the product diaminonaphthalene is maintained.

Disclosed are novel phosphine-phosphoramidite compounds which may be employed in combination with a catalytically-active metal to effect a wide variety of reactions such as asymmetric hydrogenations, asymmetric reductions, asymmetric hydroborations, asymmetric olefin isomerizations, asymmetric hydrosilations, asymmetric allylations, asymmetric conjugate additions, and asymmetric organometallic additions. Also disclosed are a process for the preparation of the phosphine-phosphoramidite compounds, metal complex compounds comprising at least one of the phosphine-phosphoramidite compounds and a catalytically-active metal and hydrogenation processes utilizing the metal complex compounds.

The invention discloses a catalyst for preparing halogenated aniline through catalytic hydrogenation of halogenated nitrobenzene. The catalyst comprises an activated carbon carrier and active component platinum adhered to the activated carbon carrier, and the mass percent of platinum in the catalyst is 0.1%-5%. The preparation method of the catalyst comprises the following steps: 1, pretreating activated carbon with inorganic acid, then washing to be neutral, and reserving after drying; 2, placing the dried activated carbon in carbonate aqueous solution for impregnating; 3, dissolving a platinum compound in water to obtain active component solution; 4, dripping the active component solution into the carbonate aqueous solution with impregnated activated carbon, carrying out insulated impregnating, adjusting the pH value of the system, and filtering after cooling to obtain a filter cake; 5, reducing the filter cake with a reducing agent, washing to be neutral, and drying to obtain the catalyst. The catalyst is simple in preparation process, can be repeatedly used, is high in reactivity, high in selectivity and good in stability, and can inhibit the side reactions of dehalogenation effectively.

The invention relates to a series of novel chiral phosphorus ligands of formulae (Ia) and (Ib): wherein R, 1-rR>4 and X are as defined herein. The invention also relates to chiral metal complexes prepared with these chiral phosphorus ligands. The chiral metal complexes are useful as catalysts for carrying out asymmetric hydro genation.

The invention provides a method for preparing 4-amino diphenylamine by catalytic hydrogenation. The method adopts two sections of hydrogenation reaction processes, and comprises the following steps: performing the condensation reaction of condensation solution formed by the condensation reaction of nitrobenzene and aniline which serve as raw materials under an alkaline condition by using using a noble metal hydrogenation catalyst and a nickel catalyst sequentially so as to make the conversion rate of 4-nitroso diphenylamine, 4-nitro diphenylamine and azoxybenzene achieve 100 percent; and separating the noble metal hydrogenation catalyst and the nickel catalyst by using a two-stage membrane separation component system to avoid the loss of small particles of catalyst. At the same time, the method has high degree of automation and can easily realize the continuous hydrogenation process.

The invention discloses a chiral tridentate PNN ligand and application of the same in asymmetric hydrogenation and similar reactions. The tridentate nitrogen phosphine ligand disclosed in the invention has been the first reported nitrogen phosphine ligand containing chiral oxazoline so far and has been successfully applied to high-efficiency and high-selectivity hydrogenation and similar reactions of ketone and imine salts. Compared with other ligand, the ligand provided by the invention is simpler in synthetic route, higher in yield and environment-friendlier; moreover, the metal complex of the ligand shows better selectivity and a higher turn-over number in asymmetric hydrogenation. An iridium complex of the chiral tridentate PNN ligand has successfully realized asymmetric reduction of beta-ketone ester into beta-alcohol ester (which is a raw material for synthesis of molecular drugs duloxetine and atomoxetine), asymmetric hydrogenation of alpha-hydroxyacetophenone into alpha-hydroxyphenylethyl alcohol and asymmetric hydrogenation of acetophenone into phenylethyl alcohol, which is of important significance to production of the medical industry.

The invention relates to a preparation method of Z-1,1,1,4,4,4-hexafluoro-2-butene, belonging to the field of chemical synthesis. The method comprises the following steps of taking hexachlorobutadiene (HCBD) as a raw material, performing gas-phase catalytic chlorination-fluoridation separation to obtain 2,3-dichlorohexafluoro-2-butene, performing liquid-phase dechlorination to obtain hexafluoro-2-butyne, and preparing the Z-1,1,1,4,4,4-hexafluoro-2-butene (Z-HFO-1336mzz) by means of performing gas-phase catalytic hydrogenation, wherein three reactions are included totally. The Z-1,1,1,4,4,4-hexafluoro-2-butene with high selectivity is obtained by means of performing catalytic hydrogenation by adopting the hexafluoro-2-butyne, and meanwhile the product is easily separated from side products and the raw material. The method disclosed by the invention has the advantages that the original raw material is easily obtained, the activity of a catalyst is high, the service life of the catalyst is long, the raw material can be recycled, and the standard of zero emissions is reached.

The invention discloses a method for preparing cis-pinane by asymmetric catalytic hydrogenation of alpha-pinene, and belongs to the chemical engineering field. The method comprises the process steps: in a nitrogen atmosphere, heating RhCl3.3H2O to dissolve in an ethanol solution, and forming a solution A; dissolving newly recrystallized PPh3 in a deoxygenated ethanol, and forming a solution B; adding the solution B into the solution A, refluxing for a certain period of time, filtering under reduced pressure while being hot, washing with deoxygenated ether, carrying out vacuum drying to obtain a rhodium phosphine complex RhCl(PPh3)3; and adding the prepared rhodium phosphine complex RhCl(PPh3)3, an ionic liquid and alpha-pinene into a high-pressure reaction kettle according to a certain proportion, putting a cover and sealing, respectively replacing with nitrogen gas and hydrogen gas, carrying out pressure maintaining and leakage detection, and carrying out a reaction under certain conditions to prepare cis-pinane. The method has the advantages of mild reaction conditions, high conversion rate of alpha-pinene and high enantioselectivity of cis-pinane; the ionic liquid catalyst system is easily separated from the product and can be recycled; and the process flow is simple, and the energy consumption is low.

A catalyst with high reaction activity, selectivity and stability for preparing halophenylamine by catalytic hydrogenation of halonitrobenzene is composed of carrier (ZrO2, TiO2, SiO3, or MgO) and active component (Au) (0.5-10 Wt %). Its preparing process includes such steps as providing chloroauric acid as precursor, depositing with urea, and ageing, washing, drying, and calcining at 200-350 deg.C.

An object of the present invention is to provide a method for manufacturing an optically active menthol having fewer steps, which generates less environmentally polluting waste because a catalytic reaction is involved in all of the steps, and is capable of saving a production cost. The present invention relates to a method for manufacturing an optically active menthol, including the following steps: A-1) asymmetrically hydrogenating at least one of geranial and neral to thereby obtain an optically active citronellal, B-1) conducting a ring-closure reaction of the optically active citronellal in the presence of an acid catalyst to thereby obtain an optically active isopulegol, and C-1) hydrogenating the optically active isopulegol to thereby obtain an optically active menthol.