127 results about "Silver catalyst" patented technology

The invention relates to the technical field of catalyst carriers, and relates to a modified alpha-alumina carrier, a preparation method thereof, a supported silver catalyst and application. The modified alpha-alumina carrier is an alpha-alumina carrier with a silane coupling structure on the surface, and silane is at least one of silane compounds containing 1-3-Si-O-C-structures and containing vinyl or amino. Preferably, the silane compound is selected from at least one of vinylmethoxysilane, 3-aminopropyltriethoxysilane and methylvinyldimethoxysilane. According to the modified alpha-alumina carrier, the silane solution is adopted to treat the alpha-alumina carrier, silane contains a-Si-O-C-structure, the group can form a relatively stable structure on the surface of the carrier after hydrolysis or dehydration condensation, and influence is generated for a long time in the use process of a silver catalyst, so that the performance of the catalyst is improved.

The present invention belongs to the field of catalysts and relates to an α-alumina carrier and a preparation method thereof, a silver catalyst for ethylene epoxidation and an ethylene oxidation method. The α-alumina carrier has an α-A12O3 content of more than 90% by weight; a crushing strength of 80 to 350 N / particle; and a specific surface area of ​​1.5 to 3.0 m 2 / g; water absorption rate is 30-70%; pore volume is 0.30-0.75mL / g; the crystal morphology of the α-alumina carrier includes two sizes of flake crystals, wherein the size of the larger flake crystals is 1.0-8.0μm, and the size of the smaller flake crystals is less than 1μm. Compared with the prior art, the silver catalyst made of the α-alumina carrier provided by the present invention is used for the reaction of ethylene oxidation to produce ethylene oxide, while ensuring selectivity, and has the advantages of higher activity and stability.

The invention discloses a preparation method and application of a silver catalyst for ethylene epoxidation, and the preparation method comprises the following preparation steps: S1, preparing an alpha-aluminum oxide and nano silicon oxide composite carrier; s2, preparation of the silver catalyst for ethylene epoxidation: S21, adding an auxiliary agent and a co-auxiliary agent into a silver ammonia solution to prepare an impregnation liquid, and impregnating the composite carrier with the impregnation liquid under negative pressure; s22, filtering out the impregnation liquid, drying the impregnated composite carrier, and activating the obtained carrier in a dark room without oxygen; s23, repeatedly dipping and activating for 2-3 times; s24, performing vacuum drying on the impregnated and activated composite carrier obtained in the step S23; and S25, roasting the composite carrier obtained in S24 in an inert atmosphere to prepare a silver catalyst finished product. The silver catalyst has the beneficial effects that the silver catalyst has very good catalytic performance when being applied to preparation of ethylene oxide through ethylene oxidation. The activity is high, and the reaction temperature is 220-240 DEG C. The selectivity is high, and the highest initial selectivity can reach 85%.

A method of reducing carbon dioxide, with a catalyst including silver, copper, and melamine, where the catalyst includes 1-20 wt. % silver based on a weight of the copper, where particles of the catalyst have a polygonal shape and an average size of 0.5-3 μm, and where the copper and the silver form a complex with the melamine.

The present invention belongs to the field of industrial catalysts, and particularly relates to a silver catalyst, a preparation method thereof and an application. The method comprises the following steps: 1) impregnating an alumina support with an organic amine solution containing a silver compound; 2) leaching to remove the excess impregnating solution and centrifuging the separated solid particles of the alumina support; 3) impregnating the centrifuged solid particles with an alcohol solvent miscible with water; 4) leaching to remove the excess alcohol solvent and separating the solid particles of the alumina support; 5) heating and activating the obtained solid particles to prepare the silver catalyst. The difference in silver loading between the inside and outside of the silver catalyst prepared by the present invention is reduced, and the active component silver metal is more uniformly loaded on the support. When used in the reaction of ethylene oxidation to produce ethylene oxide, it has improved activity and stability.

The present invention discloses a nano copper-based catalyst, its preparation method, and its application in the electrocatalytic reduction of carbon dioxide and carbon monoxide. Copper chloride (or copper nitrate, copper acetate) is dissolved in ultrapure water, and a sodium borohydride solution is added dropwise. Stir at room temperature for 5-60 min, filter, and dry to obtain a nano copper catalyst. Further, through a displacement reaction, nano copper-palladium and copper-silver catalysts are obtained. The present invention is applied to the electrocatalytic reduction of carbon monoxide. In a membrane electrode assembly (MEA) electrolyzer, the Faraday efficiency of multi-carbon products (C2+) reaches up to 95%, the partial current density reaches up to 3 A cm-2, and the overall electrolyzer energy efficiency reaches up to 39%. It can stably electrolyze for 30 hours at 1 A cm-2. This nano copper catalyst is applied to the electrocatalytic reduction of carbon dioxide. In an MEA electrolyzer, the Faraday efficiency of C2+ reaches up to 66%, and the partial current density reaches up to 331 mA cm-2.

A method for catalytic vapor phase oxidation of methanol to formaldehyde may include: passing a feed stream comprising methanol and oxygen through a layered catalyst bed having a first layer comprising a first silver catalyst particles and a second layer comprising a second silver catalyst particles that are different than the first silver catalyst particles, wherein the feed stream passes through the first layer before the second layer, wherein the first silver catalyst particles has a greater reaction activity for converting methanol and oxygen to formaldehyde; and reacting the methanol and the oxygen in the presence of the catalysts to produce a product stream comprising formaldehyde.

The present application belongs to the field of silver catalysts, and relates to a silver catalyst for ethylene oxidation to produce ethylene oxide, and a preparation method and application thereof. The silver catalyst comprises an alumina carrier, silver supported thereon, nano manganese dioxide and an additive. The content of the silver is 2-39 wt% based on the total weight of the silver catalyst; the content of the nano manganese dioxide is 0.001-0.5 wt%. The silver catalyst is obtained by impregnating the alumina carrier in a silver ammonia solution, solid-liquid separation and calcination. The silver ammonia solution comprises a chelating agent, and the content of the chelating agent is 0.01-20.0 wt%. The porous alumina carrier is impregnated in the silver ammonia solution containing the chelating agent and the nano manganese dioxide, and the silver catalyst prepared therefrom has high reactivity, and is particularly suitable for the reaction of ethylene oxidation to produce ethylene oxide.

The invention relates to the technical field of synthesis of chemical products, and particularly discloses a method for synthesizing glyoxal through gas-phase catalytic oxidation of ethylene glycol. According to the scheme provided by the invention, the good catalytic activity of the catalyst is maintained, the favorable condition of a high-temperature environment is fully utilized, the defect of poor activity of a silver catalyst in the high-temperature environment is overcome, and the yield of glyoxal is favorably improved. On the basis, a more appropriate reaction temperature range is further optimized, a catalytic system at a lower temperature is improved, and a higher glyoxal yield is obtained under various different temperature conditions.

The invention belongs to the technical field of electrocatalytic carbon dioxide reduction catalysts, and discloses a silver-based catalyst suitable for fluctuating carbon dioxide electrolysis and a preparation method of the silver-based catalyst. The preparation method comprises the following steps: uniformly and continuously dropwise adding a potassium hydroxide solution into a silver nitrate solution to prepare a silver oxide catalyst, and further applying a constant reduction current to the silver oxide catalyst in the presence of carbon dioxide gas for in-situ reduction to prepare the quintuple twin crystal silver-based catalyst. The preparation method disclosed by the invention combines precipitation titration and in-situ electroreduction methods, and has the characteristics of simplicity in operation, greenness, high efficiency and suitability for mass production; meanwhile, the catalyst can maintain high selectivity to carbon monoxide products in an extremely wide potential window range of 3V when being used in an electro-catalysis carbon dioxide conversion reaction, and is very suitable for being directly matched and coupled with fluctuating renewable energy sources.

The invention discloses a silver catalyst suitable for a high airspeed condition and a one-step impregnation preparation method thereof, and belongs to the technical field of catalyst preparation. The applicable airspeed range of the silver catalyst prepared by the method is 5000-7000h <-1 >, the temperature is 227-260 DEG C, the silver content is 18-22wt%, the silver catalyst only needs one impregnation step after the catalyst impregnation liquid and the impregnation process are optimized, the obtained silver catalyst is suitable for high airspeed, the silver content in the catalyst is reduced, and the silver content in the catalyst is reduced. And the selectivity of the catalyst product is further improved. The catalyst can directly oxidize ethylene to produce ethylene oxide, the silver content is 18-22 wt%, the catalyst can be prepared by adopting a one-step impregnation method, the preparation steps are simplified, and the cost of the catalyst is reduced.

The invention discloses a preparation method of a silver catalyst, which comprises the following steps: cleaning rice husks, drying to obtain dried rice husks, and refluxing the dried rice husks in a hydrochloric acid solution for 18-25 hours; the method comprises the following steps: taking out rice hulls in a hydrochloric acid solution, washing the rice hulls with distilled water until the rice hulls are neutral, drying the neutral rice hulls, feeding the dried neutral rice hulls into ethanol according to a ratio of clean rice hulls to silver nitrate of 8: (0.8-1.2), stirring at normal temperature, and distilling the ethanol after the silver nitrate is in full contact with the clean rice hulls to obtain a solid. The invention also comprises a use method of the silver catalyst. Cheap and easily available rice husks are matched with silver, a series of treatments are carried out to form a porous carrier, the added value of the rice husks is increased, the production cost of the catalyst is greatly reduced, the performance is stable, the safety is high, and as a hydrogenation catalyst, the reaction risk of catalytic hydrogenation is greatly reduced; and the reaction safety is greatly improved.

The invention belongs to the field of silver catalysts, and relates to an alpha-alumina carrier, a preparation method thereof, a silver catalyst and application of the silver catalyst in preparation of ethylene oxide through ethylene epoxidation. The alpha-alumina carrier contains single crystal lamellar alumina, and the content of the single crystal lamellar alumina is 0.1-50 wt% on the basis of the total weight of the alpha-alumina carrier. The preparation method comprises the following steps: preparing a mixture containing micron-sized alumina, pseudo alumina monohydrate, a mineralizer and single crystal lamellar alumina, and mixing the mixture with an acid solution; and kneading the obtained material, performing extrusion molding, drying and roasting to obtain the alpha-alumina carrier. The silver catalyst prepared from the alpha-alumina carrier provided by the invention is used for preparing ethylene oxide through ethylene epoxidation, can significantly improve the selectivity and stability of the reaction, can significantly reduce the emission of a carbon dioxide by-product, improves the utilization rate of an ethylene raw material, and has a wide industrial application prospect.

The invention provides a method for preparing a 2-acyl pyrrole compound, and belongs to the technical field of organic chemical preparation, and the specific synthesis method is as follows: in an organic solvent, beta-carbonyl propargylamine is used as a starting material, and under the action of a silver catalyst and alkali, in an oxygen atmosphere, a reaction is performed for 2-6 hours at the temperature of 60-80 DEG C; the 2-acyl pyrrole compound is synthesized in one step through a cascade reaction of hydroalkylation and oxidative dehydrogenation in an alkyne molecule; according to the synthesis method, raw materials are simple and easy to obtain, reaction conditions are mild, operation is easy, the number of reaction steps is small, atom economy is high, the 2-acyl pyrrole compound is directly obtained through one-step reaction, and the yield can reach 82%.

The present invention relates to a continuous process for preparing ethylene oxide in the presence of an activated heterogeneous silver catalyst and a production unit for carrying out said process.

To provide a method for manufacturing a metal or alloy thin film imparted anion exchange membrane that uses a catalyst nucleus having a high-mounting possibility and inexpensive as compared to palladium but allows electroless deposition of a wide range of metal species on an anion exchange membrane.SOLUTION: A method for manufacturing a metal or alloy thin film imparted anion exchange membrane including a metal or alloy thin film on at least one of surfaces of an anion exchange membrane includes the steps of: imparting a silver catalytic nucleus to at least one of the surfaces of the anion exchange membrane; and immersing the anion exchange membrane imparted with the silver catalytic nucleus into an electroless deposition bath including (a) one or more types of metallic salts, (b1) amine borane, and (b2) a reductant in accordance with the metal or alloy to be deposited to reduce the metal salts and deposit the metal or alloy at the surface imparted with the silver catalytic nucleus of the anion exchange membrane.SELECTED DRAWING: None

The invention discloses a fire extinguishing agent special for a lithium ion battery fire as well as a preparation method and application thereof, and belongs to the technical field of lithium ion battery fire extinguishing agents. The main component of the special fire extinguishing agent for the lithium ion battery fire comprises a 16F fluorocarbon, and a preparation method of the 16F fluorocarbon comprises the following steps: (1) fluorination reaction: mixing cyclohexanone, silver fluoride and a catalyst, and reacting under the protection of ice bath and inert gas; (2) epoxidation reaction: adding the suprapoeia acid salt and silver metal particles, heating in a water bath, and fully reacting; and (3) further fluorination: taking the obtained product as a raw material, repeating the steps (1) and (2), and then purifying to obtain the product. The preparation method has the beneficial effects that the obtained C8F16O fluorocarbon has excellent high insulation performance, and does not cause short circuit or other electrical faults; a large amount of heat can be quickly absorbed, and the fire source temperature is effectively reduced. Due to the characteristic, the fire extinguishing efficiency is improved, and the heat radiation influence of a fire disaster on the surrounding environment is reduced.

The present application includes a method for preparing an alkylene oxide from an alkene that comprises reacting the alkene with ozone in the presence of a silver catalyst under conditions for selective partial oxidation of the alkene to provide the alkylene oxide at low temperatures.

The invention relates to a copper-indium-silver catalyst, a preparation method thereof and a method for preparing synthesis gas with an adjustable ratio of carbon monoxide to hydrogen through electrocatalysis of carbon dioxide. The preparation method comprises the following steps: dispersing a multi-walled carbon nanotube in water to obtain a dispersion liquid A; dispersing copper nitrate trihydrate, indium nitrate hydrate and silver nitrate in water to obtain dispersion liquid B; mixing the dispersion liquid A and the dispersion liquid B to obtain dispersion liquid C; adding alkali into the dispersion liquid C to obtain a mixed solution D; and filtering and drying the mixed solution to obtain the copper-indium-silver electrocatalyst. The invention also provides the copper-indium-silver catalyst prepared by the method and a method for preparing synthesis gas with an adjustable ratio of carbon monoxide to hydrogen by electrocatalysis of carbon dioxide. According to the copper-indium-silver electrocatalyst provided by the invention, an electron-rich Cu site is formed by utilizing the synergistic effect of three metals, CO2 adsorption and CO desorption are promoted, and HER is inhibited, so that CO2RR and HER are balanced, and the selectivity of carbon monoxide synthesis gas is effectively improved.

This invention relates to a method for preparing a highly efficient silver single-atom bactericidal material. The invention utilizes an oxide as a carrier, modifies the oxide surface with phenolic compounds, anchors silver ions with phenolic hydroxyl groups to achieve uniform dispersion, and finally reduces the silver ions to silver single atoms via hydrogen reduction, ultimately obtaining a single-atom silver catalyst supported on the oxide carrier surface. This invention uses inexpensive, mass-producible commercial oxides as carriers, and through two simple steps—phenolic compound modification and hydrogen reduction—obtains a highly efficient single-atom silver bactericidal material with a low loading. The preparation steps are simple, the synthesis time is short, no large-scale equipment is required, it is easy to promote and apply, and it has a wide range of applications, suitable for bactericidal use on both solid surfaces and inside liquids.

The invention relates to silver ion antibacterial non-woven fabric for a mask and a preparation method of the silver ion antibacterial non-woven fabric, and belongs to the technical field of functional fabric. The antibacterial non-woven fabric takes needle-punched non-woven fabric as a base material and is loaded with self-made silver-series antibacterial particles, a composite antibacterial agent takes tetrapod-like zinc oxide whiskers as a carrier, sulfur-containing groups and primary alcohol groups are introduced to the surface for modification, then primary alcohol is oxidized into aldehyde groups through a silver catalyst, silver and yttrium are adsorbed and reduced, and a silver-yttrium element loaded structure is formed. Silver generates active oxygen groups which interfere with the activity and function of bacteria, and yttrium element promotes silver to generate active oxygen groups, so that an excellent antibacterial effect is achieved; besides, sodium alginate is used as a main film forming material, starch and gelatin are compounded to improve initial adhesiveness, a water-soluble coating film is formed on the surface of the composite antibacterial agent, when the antibacterial non-woven fabric is applied to a mask, antibacterial components can be dissolved and released along with exhaled wet gas, and tests show that the prepared antibacterial non-woven fabric can play a stable antibacterial role within 24 h.

The invention relates to the field of early warning regulation and control methods suitable for the process of producing a silver catalyst for catalyzing ethylene epoxidation, and relates to a regulation and control method and system suitable for the process of producing a silver catalyst for catalyzing ethylene epoxidation. Comprising the following steps: (1) acquiring normal working condition historical data of impregnation liquid in an impregnation section of the silver catalyst for ethylene epoxidation; (2) performing normalization preprocessing on the historical data of the normal working condition, setting upper and lower alarm thresholds according to data distribution, and obtaining a conventional data change trend; (3) monitoring real-time sampling data of the impregnation liquid on line, judging whether the real-time sampling data conforms to a conventional data change trend or not, and sending out an alarm signal if the real-time sampling data does not conform to the conventional data change trend; and (4) receiving the alarm signal, and carrying out regulation and control processing operation. According to the regulation and control method, the solution containing the precious metal salt can be fully utilized, and the production cost is reduced to the maximum extent.

The invention discloses an ethylene oxide catalyst without chlorine injection in the use process and a preparation method and application thereof, and relates to the technical field of ethylene oxide catalysts, the preparation method comprises the following steps: obtaining an alpha-Al2O3 carrier; a silver source, a nickel source and a reducing agent are added into a solvent to be mixed, and impregnation liquid is obtained; the alpha-Al2O3 carrier is added into the impregnation liquid for impregnation, and a catalyst precursor is obtained; and reducing the catalyst precursor to obtain the ethylene oxide catalyst. By adding iron, cobalt, nickel and other transition metals, the selectivity of the silver catalyst can be effectively improved, a stabilizing effect similar to chlorination is achieved, the ethylene oxide catalyst which does not need chlorine injection in the using process is prepared, and the defects in the prior art are effectively overcome.

The invention belongs to the technical field of catalysts, and discloses a silver catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: a, preparing a silver-containing impregnation liquid; b, the alpha-aluminum oxide carrier is loaded into a rotor of a supergravity rotating packed bed, the loading amount of the alpha-aluminum oxide carrier is 200-500 g / L, the rotating speed of the rotor is 600-1500 r / min, the silver-containing impregnation liquid is sprayed to the inner edge of the rotor and fully makes contact with the alpha-aluminum oxide carrier in the rotor in the radial direction for impregnation, the alpha-aluminum oxide carrier is circularly impregnated with the silver-containing impregnation liquid, and the silver-containing impregnation liquid and the alpha-aluminum oxide carrier in the rotor are fully impregnated; the circulation flow of the silver-containing impregnation liquid is 0.5-1.0 L / min, and the circulation impregnation time is 5-30 min; and c, activating the impregnated alpha-alumina carrier to obtain the silver catalyst. The silver catalyst provided by the invention has obviously improved activity and stability.

The application discloses a carbon-loaded silver catalyst and a preparation method and application thereof. Silver nitrate and carbon are impregnated at room temperature, and then the obtained precursor is ground into powder at room temperature, and the carbon-loaded silver catalyst is obtained after calcination. The carbon-loaded silver catalyst can be applied to electrocatalytic reduction of carbon dioxide to carbon monoxide. The application mainly adjusts the calcination temperature in the preparation process to adjust the interaction between silver and carbon. The formation of the carbon-loaded silver with a carbon semi-coating structure not only strengthens the electron transfer in the reaction process, but also strengthens the adsorption and stability of an intermediate COO ‑ . In addition, the enhancement of the interaction between silver and carbon limits the reconstruction of silver in the reaction process, and realizes stability at a high current. The application in the reduction of carbon dioxide to carbon monoxide shows excellent performance in the reduction of carbon dioxide to carbon monoxide.

The invention belongs to the technical field of catalysts, and discloses an alpha-alumina carrier and a preparation method thereof, a silver catalyst for ethylene epoxidation and an ethylene oxidation method, the preparation method comprises the following steps: preparing a solid mixture; the solid mixture is put into a rotor to be evenly mixed, the rotating speed R1 of the rotor ranges from 100 r / min to 300 r / min, and the alternating interval of forward rotation and reverse rotation of the rotor ranges from 2 s to 10 s; s3, the rotating speed R2 of the rotor is adjusted to be 200-500 r / min, the alternating interval between forward rotation and reverse rotation of the rotor is 2-10 s, and the binder makes full contact with the solid mixture in the rotor in a spraying mode; s4, the rotating speed R3 of the rotor is adjusted to be 800-1500 r / min, the alternating interval between forward rotation and reverse rotation of the rotor is 2-10 s, the solid mixture added with the binder forms paste, and extrusion molding is conducted; and S5, drying the molded body, and roasting at high temperature to obtain the alpha-alumina carrier. The pore permeability of the carrier is improved, and the selectivity and stability of the silver catalyst are improved.

The application belongs to the field of catalysts, and relates to an alpha-alumina carrier and a preparation method thereof, a silver catalyst for ethylene epoxidation, and an ethylene oxidation method. The preparation method of the alpha-alumina carrier comprises the following steps: preparing a solid mixture with the following components: trihydro-alpha-Al2O3, pseudo-monohydrate Al2O3, a pore-forming agent, a combustible lubricating material, a fluoride mineralizer, and an alkaline earth metal compound; wherein the pore-forming agent is a non-spherical organic polymer particle; mixing the solid mixture, a binder, and optional water, kneading, and extruding into a shaped body; drying and calcining the shaped body to obtain the alpha-alumina carrier. The application uses different forms of non-spherical organic polymer particles as the pore-forming agent, which has no residue during the calcination of the carrier, and can form a specific pore shape, improve the connectivity between the pores of the carrier, reduce the tortuosity, and improve the permeability, which can significantly improve the activity and selectivity of the catalyst.

This invention belongs to the field of silver catalysts, and relates to an α-alumina support, its preparation method, and silver catalysts and their applications. The preparation method of the α-alumina support includes the following steps: at least one of α-Al₂O₃ and α-Al₂O₃ trihydrate is mixed uniformly with pseudo-Al₂O₃ to obtain a solid mixture; this mixture is then wet-milled with deionized water in a ball mill to obtain a slurry; the resulting slurry is spray-granulated to obtain solid microsphere powder; the solid microsphere powder is mixed uniformly with a binder, flow aid, lubricant, and pore-forming agent to obtain pressed granules; the pressed granules are dry-pressed to obtain a molded body, which is then calcined to obtain the α-alumina support. The support obtained by this invention has a more controllable shape, and when used for the oxidation of ethylene to ethylene oxide, its selectivity and stability are significantly improved while maintaining activity.

The present application relates to a kind of initiator of preparation triangular nano silver base ethylene oxide catalyst and its application, it is related to the technical field of ethylene oxide catalyst preparation, the initiator includes the following components by weight percentage: water 5~20wt%, polyvinylpyrrolidone 0.1~20wt%, normal alkane alcohol 65~85wt% and ethanol 1~20wt%;Wherein, the normal alkane alcohol is at least one in C3~C6 normal alkane alcohol.The present application is by using the initiator of this specific composition as the mother liquor system of silver base ethylene oxide catalyst impregnation liquid, the morphology control is applied to silver base ethylene oxide catalyst, after silver is uniformly dispersed in carrier, morphology is controlled synthesis, and triangular nano silver morphology silver base ethylene oxide catalyst is prepared, the preparation of controllable morphology controllable nano silver catalyst is realized, the contact area of nano silver with reactant is increased, to improve the performance of triangular nano silver base ethylene oxide catalyst.

The invention relates to the technical field of electrocatalytic reduction, and discloses a method for electrocatalytic reduction of CO2 by using a silver catalyst with a low coordination structure, and the method comprises the following steps: (1) preparing silver powder to obtain an Ag NPs electrode, and preparing an AgO electrode by using the Ag NPs electrode as a working electrode and adopting a cyclic voltammetry method; and (2) carrying out electrochemical reduction modification by taking the AgO electrode as a cathode electrode, and finishing the modification when the voltage is stable, so as to prepare the silver catalyst with a low-coordination structure. And (3) carrying out electrocatalytic reduction on CO2 by taking the silver catalyst with a low coordination structure as a cathode electrode. Through electrochemical in-situ modification, a low-coordination structure is introduced under the condition that the morphology structure and the valence of the silver catalyst are not changed, the catalytic activity and the catalytic stability are greatly improved, operation is easy and convenient, and large-scale industrial application is facilitated.