32 results about "Selective catalyst" patented technology

The invention relates to a modified Fe-Mo series formaldehyde catalyst and a method, the active component of the catalyst is metal salt of Fe and Mo, the auxiliary agent is salt of one or more metals M selected from K, Mg, Al, Ba and Ni, the mass ratio of M is 0.1-5%, the preferential amount of K is 0.1-0.5%, the preferential amount of Mg is 0.1-1.5%, the preferential amount of Al is 1.0-3.5%, the preferential amount of Ba is 1.0-3.5%, and the preferential amount of Ni is 2-5.0%. According to the preparation method of the catalyst, a coprecipitation method is adopted, the prepared catalyst is wide in pore size distribution by controlling the reaction speed of coprecipitation, and then the catalyst is pressed into a hollow cylinder shape or a four-leaf clover shape. According to the catalyst, the conversion rate of methanol and the selectivity of formaldehyde are improved, and the stability of the catalyst is good.

The application relates to the field of organic chemistry, in particular to a method for photocatalytic synthesis of silanol or silyl ether. The application provides a method for photocatalytic synthesis of silanol or silyl ether compound, in which, under the condition of existence of an iridium catalyst and an organic solvent, hydrosilane is reacted with any one of water, alcohol or phenol under light to obtain silanol or silyl ether. The synthesis method has high yield and selectivity, low catalyst consumption, mild reaction condition and high environmental protection and efficiency.

The present invention provides a composite catalyst and a preparation method thereof and a synthesis method of p-methoxycinnamate compounds, wherein the composite catalyst includes a carrier modified by a modifier and a metal salt and a choline substance supported by the carrier. In the presence of the composite catalyst of the present invention, a Claison-Schmidt condensation reaction is catalyzed between aromatic aldehyde compounds and acetate compounds to obtain p-methoxycinnamate. The composite catalyst provided by the present invention has high reactivity and selectivity, a stable catalyst structure, and active ingredients are not easily lost, and the recycling of the catalyst can be achieved without frequent replacement of the catalyst. The operation is simple, and the operation is conducive to continuous industrial production, significantly improving equipment utilization. The use of the composite catalyst provided by the present invention can make the preparation of p-methoxycinnamate compounds react under relatively mild reaction conditions, without corrosion to the equipment, and without wastewater or waste salt generation, which is green and environmentally friendly.

An exhaust aftertreatment unit for cleaning exhaust gases, the exhaust aftertreatment unit including a fluid channel for providing a fluid pathway for the exhaust gases, the fluid channel having an outer casing; a catalyst casing housing a selective catalyst reduction (SCR) catalyst and an ammonia slip catalyst (ASC) arranged downstream of the SCR catalyst, the catalyst casing being arranged inside the outer casing forming an intermediate space between the inner and outer casings; and a detector configured to measure ammonia and / or NOx in the exhaust gases; wherein the catalyst casing includes one or more perforations upstream of the ASC to enable a by-pass flow of exhaust gases from inside the catalyst casing into the intermediate space, and wherein the detector is arranged in the fluid channel to measure the ammonia and / or NOx in the exhaust gases including the by-pass flow.

The application discloses a shape-selective catalyst for preparing 4,4'-disubstituted diphenylmethane by alkylation and a preparation method and application thereof. The catalyst is composed of a molecular sieve and an oxide for modifying the molecular sieve. The oxide is an oxide corresponding to the highest valence of a modified element. The modified element includes phosphorus, titanium, zirconium, gallium, indium, germanium, molybdenum, tungsten, rhenium or copper. The mass content of the oxide in the catalyst is 0.01-20% in the catalyst with a mass of 100%. The catalyst has good thermal stability and chemical stability, can be repeatedly used, has a simple regeneration method and a high activity recovery rate.

The present invention relates to a highly active and selective catalyst comprising a mixture of cerium oxide, nickel oxide and ruthenium, of formula Ru / NiO-CeO2, wherein the nickel cations are inside the cerium particles, forming a mixed oxide, and wherein the ruthenium is dispersed on the surface of the NiO-CeO2 particles. The invention also relates to the use thereof in product conversion, such as the production of synthetic natural gas or hydrogen, in particular using starting materials selected from resins and plastics or using ethanol.

The invention provides a C3 fraction selective catalyst. The catalyst comprises a carrier and an active component loaded on the carrier, wherein the carrier is a metal composite oxide modified by an organic cation quaternary ammonium salt and a silane reagent; the metal element I in the metal composite oxide comprises aluminum and titanium; the metal element II in the active component comprises a main active component noble metal Pd and an optional auxiliary active component, the auxiliary active component comprises transition metal and / or alkaline earth metal, the transition metal is selected from one or more of Cu, Mn, Ni and Zn, and the alkaline earth metal is selected from one or more of Ca, Mg and Ba. The carrier is modified through the organic cation quaternary ammonium salt and the silane reagent, the dispersity of active components on the surface of the carrier can be remarkably improved, and the problem that the crushing strength of metal composite oxide is low is solved. The invention also provides a preparation method and application of the C3 fraction selective catalyst, and also provides a method for producing propylene through selective hydrogenation of C3 fractions.

Disclosed in the present invention are a system and method for preparing an aviation oil precursor from a microbial biomass residue by means of bond-breaking and reforming and catalytic pyrolysis. A gas inlet system comprises a carrier gas inlet, a nitrogen cylinder, an air cylinder, a nitrogen mass flow meter, an air mass flow meter, and a flow controller; a multi-stage pyrolysis catalysis system comprises a microbial biomass residue pusher, a first-stage heating section, a second-stage heating section, a third-stage heating section, a pyrolysis carbon collection tube, a bond-breaking catalyst bed, a shape-selective catalyst bed, a pyrolysis reactor, and a temperature controller; a product collection system comprises a fourth-stage condenser, a drying tube, and a gas collection bag. The method comprises: rapidly pyrolyzing a microbial biomass residue in a first-stage heating section; performing preliminary bond breaking and deoxidizing in a second-stage heating section to form a stable small-molecule product matching a shape-selective catalyst pore channel; and in a third-stage heating section, after entry into the shape-selective catalyst pore channel, performing aromatization for conversion into an aromatic hydrocarbon aviation oil precursor. The present invention solves the problems that intermediate products from microbial biomass residue pyrolysis show wide molecular weight distribution and do not match microporous shape-selective catalyst pore channels, target product yield is low and the like in traditional catalytic pyrolysis.

A catalyst A with isotactic selectivity and a catalyst B with random selectivity are selected to form a binary catalytic system, and the allyl block polyolefin elastomer is efficiently synthesized through chain shuttling polymerization. The melting point and the glass-transition temperature of the allyl block polyolefin elastomer can be conveniently regulated and controlled by changing the isotacticity and introducing the content of the comonomer, the melting point range is 100-160 DEG C, and the glass-transition temperature range is-50-0 DEG C. The prepared propenyl block polyolefin elastomer is novel in structure and excellent in performance and has original innovativeness.

This invention relates to the field of mixing equipment technology, and in particular to a mixing device for a selective catalyst fluid generator, comprising: a mixing cylinder having a mixing chamber, an air outlet channel formed on the right end face of the mixing cylinder, and an air inlet channel formed on the left end face of the mixing cylinder; a scraper fixed on a first feed pipe, and mixing blades installed on a second feed pipe; and a purification mechanism for removing impurities from the fluid. The purification mechanism is arranged in the air outlet channel. The rotation of the second feed pipe drives the spirally arranged mixing blades to generate a strong stirring effect. The spiral arrangement not only increases the flow path of the fluid in the mixing cylinder, but also promotes the exchange and mixing between different fluid layers. The L-shaped scraper can scrape the inner wall of the mixing cylinder, effectively preventing the fluid from depositing or scaling during the mixing process. Through the design of the purification mechanism, impurities in the fluid can be removed, improving the cleanliness of the reaction product.

A method for controlling the operation of a hydrogen combustion engine system of a vehicle. The hydrogen combustion engine system has a hydrogen combustion engine and an EATS to reduce emissions in the engine exhausts. The EATS has a selective catalyst reduction, SCR, catalyst and an ammonia slip catalyst, ASC, arranged downstream of the SCR catalyst. The method comprises: determining the temperature of the SCR catalyst; determining the temperature of the ASC; in response of determining that the temperature of the SCR catalyst is below a predetermined SCR temperature threshold value, and that the temperature of the ASC is below a predetermined ASC temperature threshold value, operating the hydrogen combustion engine in an H2 exhaust excess mode defined by an amount of unburnt H2 of at least 0.2 mol % in the engine exhausts, and using the unburnt H2 in the engine exhausts as a reductant for NOx conversion in the ASC.

The invention provides a CuO-ZnO-coated Cu-MOR high-selectivity catalyst as well as a preparation method and application of the CuO-ZnO-coated Cu-MOR high-selectivity catalyst. Specifically, the invention provides a CuO-ZnO-coated Cu-MOR catalyst capable of being used for preparing methanol through CO2 hydrogenation, the CuO-ZnO-coated Cu-MOR catalyst can be obtained by roasting a solid-phase mixture of copper salt, zinc salt and a Cu-MOR molecular sieve, the preparation method is simple and rapid, environment-friendly and energy-saving, the catalytic performance is excellent, and the methanol selectivity is high.

The invention belongs to the technical field of organic synthesis, and particularly discloses a preparation method of ocimene, which comprises the following steps: uniformly mixing alpha-pinene and a high-boiling-point solvent, preheating through a preheater, then pumping into a fixed bed reactor filled with a Ga-ZSM-5 molecular sieve catalyst at a certain flow rate for isomerization reaction, and separating and purifying to obtain the ocimene. And after the reaction, cooling by a cooler to obtain a reaction crude product, and rectifying the crude product to obtain ocimene and alloocimene. According to the method, the aprotic high-boiling-point solvent and the Ga-ZSM-5 molecular sieve are adopted as catalysts, conversion of alpha-pinene to limonene can be reduced, meanwhile, side reactions are effectively reduced, and the selectivity of ocimene is improved. The catalyst is long in service life and can be regenerated after being inactivated, the raw material conversion per pass is high, the ocimene selectivity is good, and a certain foundation is laid for industrial production of ocimene.

The invention discloses a method for preparing 4, 4 '-dihydroxybenzaldehyde through alkylation The invention discloses a shape-selective catalyst based on 4, 4 '-disubstituted diphenylmethane and a preparation method and application thereof, the catalyst is composed of a molecular sieve and an oxide for modifying the molecular sieve, the oxide is an oxide corresponding to the highest valence of a modification element, and the modification element comprises phosphorus, titanium, zirconium, gallium, indium, germanium, molybdenum, tungsten, rhenium or copper; the mass of the catalyst is 100%, the oxide accounts for 0.01-20% of the mass of the catalyst, and the balance is the molecular sieve. The catalyst has the advantages of good thermal stability, good chemical stability, reusability, simple regeneration method and high activity recovery rate.

The invention discloses a nitrogen-doped carbon modified Ni / MgAlO catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysts. The preparation method comprises the following steps: firstly, taking a magnesium source, an aluminum source, a nickel source and hexamethylenetetramine as raw materials, preparing NiO / MgAlO through hydrothermal reaction and roasting, then carrying out surface modification on the NiO / MgAlO by taking dopamine hydrochloride as a carbon source, and carrying out carbonization treatment in a nitrogen atmosphere to prepare the Ni / MgAlO catalyst. A strong electron interaction exists between a carbon modifier introduced by carbonization and nickel, and the migration rate of carbon generated by methane cracking on the surfaces of nickel particles is accelerated through a homogeneous repulsion action mechanism, so that the formation of coated carbon is reduced, and the catalytic activity of the catalyst and the selectivity to hydrogen are enhanced; the carbon modifier on the surface of the catalyst has a space shielding protection effect on nickel particles, carbon generated by methane cracking is prevented from directly covering the surfaces of the nickel particles, meanwhile, sintering agglomeration of the nickel particles at high temperature is inhibited, and the catalytic stability of nickel is enhanced.

A method for controlling the operation of a hydrogen combustion engine system of a vehicle. The hydrogen combustion engine system has a hydrogen combustion engine and an EATS to reduce emissions in the engine exhausts. The EATS has a selective catalyst reduction, SCR, catalyst and an ammonia slip catalyst, ASC, arranged downstream of the SCR catalyst. The method comprises: determining the temperature of the SCR catalyst; determining the temperature of the ASC; in response of determining that the temperature of the SCR catalyst is below a predetermined SCR temperature threshold value, and that the temperature of the ASC is below a predetermined ASC temperature threshold value, operating the hydrogen combustion engine in an H2 exhaust excess mode defined by an amount of unburnt H2 of at least 0.2 mol % in the engine exhausts, and using the unburnt H2 in the engine exhausts as a reductant for NOx conversion in the ASC.

A method for controls the operation of a hydrogen combustion engine system of a vehicle including a hydrogen combustion engine and an exhaust aftertreatment system, EATS, to reduce emissions in the engine exhausts. The EATS comprises a selective catalyst reduction, SCR, catalyst and an ammonia slip catalyst, ASC, arranged downstream of the SCR catalyst. The method includes: identifying a regeneration time window for performing regeneration of the ASC; in response of identifying the regeneration time window, operating the hydrogen combustion engine in an H2 exhaust excess mode defined by an amount of unburnt H2 of at least 1.5 mol % in the engine exhaust and regenerating the ASC by using the unburnt H2 in the engine exhausts and reaching a regeneration temperature of at least 500° C.

Systems and methods for producing light olefin(s) are disclosed. The method includes contacting a catalyst with a coke precursor to form a light olefin selective catalyst, and contacting the light olefin selective catalyst with a hydrocarbon feed under conditions sufficient to catalytically crack at least a portion of the hydrocarbon feed to form a products stream containing a light olefin, here the light olefin selective catalyst is more selective than the catalyst in catalyzing formation of the light olefin by the catalytic cracking of the hydrocarbon feed.

The application discloses a kind of nitrogen-doped carbon modified Ni / MgAlO catalyst and its preparation method and application, belong to catalytic technology field.The present application is with magnesium source, aluminium source, nickel source and hexamethylene tetramine as raw material, by hydrothermal reaction and calcination preparation NiO / MgAlO, then with hydrochloric acid dopamine as carbon source to its surface modification, again carbonization treatment under nitrogen atmosphere, preparation Ni / MgAlO catalyst.Carbonization introduced carbon modifier and nickel exist strong electronic interaction, and through the same kind of repulsion effect mechanism accelerates the migration rate of carbon produced by methane cracking on the surface of nickel particle, reduce the formation of coated carbon, enhance the catalytic activity and hydrogen selectivity of catalyst;Carbon modifier on the surface of catalyst prevents methane cracking generated carbon from directly covering the surface of nickel particle, while inhibiting nickel particle sintering agglomeration at high temperature, enhances the catalytic stability of nickel.

The application discloses a metal-modified Cu / MgO catalyst and a preparation method and application thereof in furfural preparation of pentanediol, and belongs to the technical field of catalysts. The metal-modified Cu / MgO catalyst provided by the application is composed of Cu, MgO and M, Cu serves as a metal active center and plays a main catalytic role in furfural hydrogenation, MgO and M jointly serve as carriers, on one hand, for loading Cu, and on the other hand, for loading a reaction substrate and providing alkaline sites; by adding a metal carrier M on the basis of the Cu / MgO catalyst, the metal carrier M can further improve the alkaline sites of the carrier, and in the preparation process of the catalyst, the metal carrier M can be partially reduced to form oxygen vacancies on the surface, which is favorable for the adsorption of a substrate on the catalyst, and thus the selectivity of the catalyst is improved; the catalyst has good hydrogenolysis activity and selectivity to furfural under relatively mild conditions, and no obvious polymer is produced.

An internal combustion engine system is described herein. The system uses an oxidation-enabled selective catalyst reactor (SCR) to treat NOx emissions and secondary exhaust components in an exhaust of the internal combustion engine. The oxidation-enabled SCR includes at least two stages: an NOx reduction stage having NOx reduction matrix configured to react with and reduce an amount of the NO2 and / or NO in the exhaust of the internal combustion engine; and an oxidation stage having an oxidation catalyst configured to oxidize at least a portion of the secondary exhaust components. The oxidation stage can be coated onto the NOx reduction matrix or may be substituted in for portions of the NOx reduction matrix.

An exhaust aftertreatment unit for cleaning exhaust gases, the exhaust aftertreatment unit including a fluid channel for providing a fluid pathway for the exhaust gases, the fluid channel having an outer casing; a catalyst casing housing a selective catalyst reduction (SCR) catalyst and an ammonia slip catalyst (ASC) arranged downstream of the SCR catalyst, the catalyst casing being arranged inside the outer casing forming an intermediate space between the inner and outer casings; and a detector configured to measure ammonia and / or NOx in the exhaust gases; wherein the catalyst casing includes one or more perforations upstream of the ASC to enable a by-pass flow of exhaust gases from inside the catalyst casing into the intermediate space, and wherein the detector is arranged in the fluid channel to measure the ammonia and / or NOx in the exhaust gases including the by-pass flow.

The invention discloses a multi-metal oxide catalyst for producing ethylene carbonate by a transesterification method and a preparation method thereof, the catalyst comprises an active component and a carrier, and the active component is loaded on the carrier; the active component is selected from at least one of MgO, CuO, CaO, La2O3, NiO, CeO and BaO; the carrier is selected from at least one of active carbon (AC), gamma-Al2O3, SiO or TS molecular sieve. According to the ethylene carbonate prepared by adopting the catalyst, the EG conversion per pass is more than or equal to 80%, the EC selectivity is more than or equal to 93%, the dosage of the catalyst is 1-5wt% of the total mass of dimethyl carbonate and ethylene glycol, and the single pass life of the catalyst is more than or equal to 100h.

An engine exhaust aftertreatment system architecture with coordinated emissions control is provided. An exhaust system architecture provides a coordinated control method that takes into account aspects of the aftertreatment components involved. An aftertreatment system under this architecture includes a conduit system that transports an exhaust stream from an engine to the atmosphere. A diesel oxidation catalyst unit is disposed in the conduit system. A selective catalyst reduction unit is disposed in the conduit system downstream of the DOC unit. A passive NOx adsorber unit is disposed in the conduit system downstream of the DOC unit at a location disposed a distance from the engine. This distance is effective to enable the SCR unit to heat to a conversion threshold temperature before the PNA unit heats to a release threshold temperature after a cold start of the engine.

This application discloses an in-situ preparation method for a catalyst, comprising the following steps: gasifying a nitrogen-containing substance and / or a phosphorus-containing substance to obtain a mixed gas, passing it into a reactor containing a support, and performing heat treatment I and heat treatment II to obtain the catalyst. This method enables the uniform introduction of active components and additives, resulting in a uniform distribution of active sites in the prepared catalyst, which is beneficial for improving the catalyst's activity and selectivity. When used in the reaction of acetate and NH3, the catalyst can suppress side reactions and achieve high acetonitrile selectivity. It avoids corrosiveness to reaction equipment, provides mild reaction conditions, has high atom utilization, and is suitable for continuous, stable, and large-scale production.

The application relates to application of a high-selectivity catalyst Cu-ZnO / TiO2 in synthesis of benzimidazole in a heterogeneous system and belongs to the technical field of catalyst preparation and application. The catalyst is prepared by using zinc nitrate hexahydrate as a zinc source, copper nitrate trihydrate as a copper source and P25 type titanium dioxide as a carrier, loading ZnO and Cu on the titanium dioxide by adopting a step-by-step precipitation method, reducing in a tube furnace by hydrogen, obtaining the catalyst Cu-ZnO / TiO2, and then catalyzing o-phenylenediamine to react to synthesize benzimidazole by taking CO2 as a carbon source and hydrogen as a hydrogen source. The Cu-ZnO / TiO2 catalyst with copper and zinc oxide contents of 5% and 4% respectively has excellent catalytic performance, under the reaction conditions of a CO2 pressure of 2.5 MPa, a hydrogen pressure of 3.5 MPa and a temperature of 180 DEG C, when the conversion rate of o-phenylenediamine is 100%, the selectivity of benzimidazole is greater than 99.9%, and the TOF value is 6.4 h ‑1 . The preparation method is simple, low in cost, high in selectivity when used for catalyzing o-phenylenediamine to react with CO2 and H2 to prepare benzimidazole, and has wide industrialization prospects.

This invention discloses a method for preparing cis-1,2-dibromoethylene based on steric hindrance, belonging to the field of technical organic synthesis. The method includes the following steps: (a) providing reactors A and B connected in series. Bromine is added to reactor A, and a solvent and configuration-selective catalyst are added to reactor B. This invention employs a series reactor system. Under the synergistic effect of a copper / crown ether composite catalyst and ultraviolet light, a highly selective addition reaction of acetylene with bromine is achieved by controlling the solvent system, reaction temperature, and material ratio. Using acetonitrile or perfluoroalkane as solvent, and copper chloride and crown ethers (such as 15-crown-5) as catalysts, the reaction is carried out at 30-80℃ under 200-400nm ultraviolet light. The selectivity of cis-1,2-dibromoethylene is ≥95%, which has advantages such as mild reaction conditions, solvent recyclability, and suitability for industrial production. Furthermore, the cis selectivity is improved to ≥95%; the content of the byproduct tetrabromoethane is <0.5%; and the solvent recovery rate is >98%.

A conditioning process that is employed with a high selectivity catalyst (HSC) during an initial phase (i.e., start-up) of the epoxidation process is provided. The HSC conditioning process of the present disclosure ensures that the heat release from a catalyst bed containing an HSC during a start-up operation is less than 2000 kJ / Kgcat.hr. The HSC containing catalyst bed that has been conditioned by the process of the present disclosure exhibits improved performance (i.e., EO selectivity) and reduced hot spots.

A method for controls the operation of a hydrogen combustion engine system of a vehicle including a hydrogen combustion engine and an exhaust aftertreatment system, EATS, to reduce emissions in the engine exhausts. The EATS comprises a selective catalyst reduction, SCR, catalyst and an ammonia slip catalyst, ASC, arranged downstream of the SCR catalyst. The method includes: identifying a regeneration time window for performing regeneration of the ASC; in response of identifying the regeneration time window, operating the hydrogen combustion engine in an H2 exhaust excess mode defined by an amount of unburnt H2 of at least 1.5 mol % in the engine exhaust and regenerating the ASC by using the unburnt H2 in the engine exhausts and reaching a regeneration temperature of at least 500° C.

To provide a method for producing a fluorinated olefin suitable for commercialization of CF3CF=CH2 (1234yf).SOLUTION: Provided is a method in which a feedstock material such as CCl2=CClCH2Cl is fluorinated to synthesize a compound such as CF3CCl=CH2 with a selectivity of 80 to 96%, CF3CCl=CH2 being converted to CF3CFClCH3 (244 isomer) using SbCl5 as a catalyst, and then selectively converted to 1234yf by a vapor-phase catalytic reaction using activated carbon as a catalyst, wherein, for the first step, a mixture of Cr2O3 and FeCl3 / C is used as a catalyst to achieve a high selectivity of 96% for CF3CCl=CH2, in the second step, SbCl5 / C is used as a selective catalyst for converting 1233xf to the 244 isomer CF3CFClCH3, and an intermediate is isolated, purified by distillation, and used in a subsequent step without further purification to a purity level exceeding about 95%.SELECTED DRAWING: None