50 results about "Selective catalyst" patented technology

The invention provides a composite catalyst and a preparation method thereof, and a synthesis method of a p-methoxy cinnamate compound. The composite catalyst comprises a carrier modified by a modifier, and a metal salt and a choline substance loaded on the carrier. In the presence of the composite catalyst provided by the invention, a Claison-Schmidt condensation reaction of an aromatic aldehyde compound and an acetate compound is catalyzed to obtain the p-methoxycinnamate. The composite catalyst provided by the invention has the advantages of high reaction activity and selectivity, stable catalyst structure, difficult loss of active components, realization of cyclic application of the catalyst, no need of frequent replacement of the catalyst, simple operation, facilitation of continuous industrial production, substantial increase of the equipment utilization rate, and realization of industrial production. By using the composite catalyst provided by the invention, the p-methoxy cinnamate compound can be prepared under relatively mild reaction conditions, and the composite catalyst has no corrosion to equipment, does not generate waste water and waste salt, and is green and environment-friendly.

The present invention relates to a method for surface modification of a MCM-22 molecular sieve shape-selective catalyst, belonging to the technical field of chemical engineering catalysis. In this preparation method, a macromolecular organic acid is selected to selectively remove the Al sites on the outer surface of the MCM-22 molecular sieve, and then a macromolecular silyl group is grafted onto the hydroxyl defect sites generated on the outer surface of the molecular sieve due to dealumination. This method can avoid blocking the pores of MCM-22, eliminate the outer surface acidity while retaining the internal activity of the molecular sieve, and reduce the pore mouth size, thereby obtaining a MCM-22 molecular sieve shape-selective catalyst with high activity, high selectivity and high stability. When this catalyst is applied to the reaction of alkylation of toluene with dimethyl carbonate to synthesize p-xylene, the activity of the catalyst remains 36% within 20 hours, and the selectivity can reach up to 66% at most.

The present invention relates to a highly selective catalyst Ni-TiO2-P25, a preparation method thereof, and an application of a photothermal synergistic catalytic selective hydrogenation of p-chloronitrobenzene in a heterogeneous system, belonging to the field of catalytic hydrogenation. The catalyst uses nickel acetate tetrahydrate as a nickel source and P25-type TiO2 as a carrier. Active metal Ni is loaded on the P25-type TiO2 by an impregnation method, and the catalyst is placed in a tubular furnace for hydrogen reduction to obtain the catalyst Ni-TiO2-P25. The Ni-TiO2-P25 catalyst with a loading of 3.5% has excellent catalytic performance. When the photocurrent density is 0.4W / cm ‑1 Under full-spectrum irradiation, 50 mg of catalyst, 2 g of p-chloronitrobenzene, a hydrogen pressure of 3 MPa, a temperature of 80°C, and a reaction time of 3.5 hours, the conversion rate reached 100%, and the selectivity reached over 99.9%. This preparation method is simple, low-cost, has a fast catalytic hydrogenation rate, high selectivity for the target product, and is easy to separate, showing promising industrial prospects.

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 discloses a system and method for catalytic pyrolysis of broken - bond reforming of mushroom residue to prepare aviation fuel precursors. The intake system includes a carrier gas inlet, a nitrogen gas cylinder, an air cylinder, a nitrogen mass flowmeter, an air mass flowmeter and a flow controller; the multi - stage pyrolysis catalytic system includes a mushroom residue pusher, a primary heating section, a secondary heating section, a tertiary heating section, a pyrolysis carbon collection tube, a broken - bond catalyst bed, a shape - selective catalyst bed, a pyrolysis reactor and a temperature controller; the product collection system includes a four - stage condenser, a drying tube and a gas collection bag. The method involves rapid pyrolysis of mushroom residue in the primary heating section, preliminary broken - bond deoxidation in the secondary heating section to form stable small - molecule products and match the pore channels of the shape - selective catalyst, and aromatization conversion into aromatic aviation fuel precursors in the pore channels of the shape - selective catalyst in the tertiary heating section. It solves the problems in traditional catalytic pyrolysis, such as wide molecular weight distribution of mushroom residue pyrolysis intermediate products, mismatch with the pore channels of microporous shape - selective catalysts, and low yield of target products.

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.

The invention provides a tandem type carbon dioxide electrocatalytic reduction reaction device which adopts a three-liquid-phase flow channel design, a CO2 saturated electrolyte flow channel, an alkaline electrolyte flow channel and an anolyte flow channel are arranged in the same reactor, and a CO selective catalyst, an alcohol selective catalyst and an anode catalyst are selected and used in a targeted manner, so that the carbon dioxide electrocatalytic reduction reaction device is obtained. According to the device, CO generation and alcohol conversion can be integrated and coordinated in the same reactor, two-step efficient conversion of CO2 to alcohol is promoted, and the device is simple and flexible in structure and wide in applicability.

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 invention discloses a preparation method of a high-entropy oxide molecular sieve interface coupling catalyst. The preparation method comprises the following steps: 1, preparing a high-entropy metal oxide; 2, preparing an H-MCM-22 molecular sieve; 3, ball-milling the high-entropy metal oxide, the H-MCM-22 molecular sieve and the zirconium oxide balls together to obtain mixed powder; and 4, tabletting, crushing and screening the mixed powder to obtain the high-entropy oxide molecular sieve interface coupling catalyst. The invention also discloses the high-entropy oxide molecular sieve interface coupling catalyst prepared by the method and application thereof. According to the preparation method of the high-entropy oxide molecular sieve interface coupling catalyst, the high-entropy oxide molecular sieve interface coupling catalyst is composed of a high-entropy oxide composed of multi-component metal and a molecular sieve with an acidic structure regulation and control capability, and the selectivity of a C8 + component in a CO2 hydrogenation reaction is remarkably improved through an interface synergistic effect; the catalyst is simple and convenient in synthesis process, high in catalytic activity, adjustable in product distribution and suitable for large-scale preparation of high-selectivity liquid fuel.

The invention relates to a methanol-to-propylene conversion method and a catalyst used in the method, and belongs to the technical field of chemical engineering. Methanol is in contact with a high-shape-selective-activity catalyst in a parallel switching fixed bed; an active component of the catalyst is aluminum-rich Pentasil structure zeolite synthesized by taking zeolite containing 0.01%-3% of gallium as a crystal nucleus, the aluminum-rich Pentasil structure zeolite contains 6%-7% of aluminum oxide, and the crystal size is 2-4 microns; the catalyst is characterized in that a carrier which has a pore volume of 0.1-0.3 ml / g with a pore diameter of 3.5-4.5 nanometers except micropores and an n-hexane / cyclohexane adsorption ratio of more than or equal to 4 and accounts for 5-40% of the catalyst is composed of boron (accounting for 0.1-1% of the carrier)-doped high-pore-volume (0.5-1.2 ml / g) aluminum oxide and aluminum phosphate sol, and phosphorus accounts for 0.1-5% of the carrier. The MTP process and the catalyst thereof are high in conversion activity, good in product selectivity and high in material circulation and heat utilization rate, and the interval period of regeneration is prolonged.

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.

Methods, apparatuses, and systems for managing a multiple, and particularly a dual-selective catalyst reduction (SCR), exhaust aftertreatment system according to one or more determined reductant dosing strategies are disclosed. A method includes: receiving, by a controller, data indicative of a catalyst of an aftertreatment system; determining, by the controller, a reductant dosing strategy based on a comparison of the data indicative of the catalyst to a respective threshold; and commanding, by the controller, an amount of reductant dosing based on the determined reductant dosing strategy.