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CN117258786A - Silver catalyst for producing ethylene oxide by ethylene oxidation and preparation method and application thereof - Google Patents

Silver catalyst for producing ethylene oxide by ethylene oxidation and preparation method and application thereof Download PDF

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Publication number
CN117258786A
CN117258786A CN202210669156.3A CN202210669156A CN117258786A CN 117258786 A CN117258786 A CN 117258786A CN 202210669156 A CN202210669156 A CN 202210669156A CN 117258786 A CN117258786 A CN 117258786A
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China
Prior art keywords
silver
silver catalyst
catalyst
content
rhenium
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Inventor
林伟
王辉
崔宝林
李金兵
高立新
崔秉全
魏会娟
李旻旭
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Sinopec Beijing Chemical Research Institute Co ltd
China Petroleum and Chemical Corp
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Sinopec Beijing Chemical Research Institute Co ltd
China Petroleum and Chemical Corp
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Priority to CN202210669156.3A priority Critical patent/CN117258786A/en
Publication of CN117258786A publication Critical patent/CN117258786A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/66—Silver or gold
    • B01J23/68—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/688—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with manganese, technetium or rhenium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B01J37/0213—Preparation of the impregnating solution
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D301/00—Preparation of oxiranes
    • C07D301/02—Synthesis of the oxirane ring
    • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
    • C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
    • C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
    • C07D301/10—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
    • C07D303/02—Compounds containing oxirane rings
    • C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Catalysts (AREA)

Abstract

The invention belongs to the field of silver catalysts, and relates to a silver catalyst for producing ethylene oxide by ethylene oxidation, a preparation method and application thereof. The silver catalyst comprises an alumina carrier, silver loaded on the alumina carrier, nano manganese dioxide and an auxiliary agent: wherein, the content of silver is 2 to 39 weight percent 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 immersing the alumina carrier in silver ammonia solution, carrying out solid-liquid separation and roasting, and the silver ammonia solution comprises chelating agent, wherein the content of the chelating agent is 0.01-20.0 wt%. The porous alumina carrier is immersed in silver ammonia solution containing chelating agent and nano manganese dioxide, and the silver catalyst prepared from the porous alumina carrier has high reaction activity and is especially suitable for ethylene oxide production reaction by ethylene oxidation.

Description

Silver catalyst for producing ethylene oxide by ethylene oxidation and preparation method and application thereof
Technical Field
The invention belongs to the field of silver catalysts, and particularly relates to a silver catalyst for producing ethylene oxide by ethylene oxidation, a preparation method of the silver catalyst for producing ethylene oxide by ethylene oxidation, a silver catalyst prepared by the preparation method of the silver catalyst for producing ethylene oxide by ethylene oxidation, and application of the silver catalyst in the reaction for producing ethylene oxide by ethylene oxidation.
Background
Ethylene is oxidized to mainly generate ethylene oxide under the action of a silver catalyst, and side reactions simultaneously occur to generate carbon dioxide and water, wherein the activity, the selectivity and the stability are main performance indexes of the silver catalyst. The activity refers to the reaction temperature required for the production process of the ethylene oxide to reach a certain reaction load. The lower the reaction temperature, the higher the activity of the catalyst. By selectivity is meant the ratio of the moles of ethylene converted to ethylene oxide in the reaction to the total moles of ethylene reacted. Stability is expressed as the rate of decrease in activity and selectivity, with lower rates indicating better catalyst stability. The use of a silver catalyst with high activity, high selectivity and good stability in the process of producing ethylene oxide by ethylene oxidation can greatly improve economic benefit, so that the production of the silver catalyst with high activity, high selectivity and good stability is the main direction of silver catalyst research. The performance of the silver catalyst has important relation with the composition of the catalyst and the preparation method, and also has important relation with the performance of a carrier used by the catalyst and the preparation method.
The preparation method of the silver catalyst in the prior art comprises a porous carrierThe preparation of the body (e.g. alumina) and the application of the active ingredient and the adjuvant to the support. In the preparation of silver catalyst, for alpha-Al 2 O 3 The carrier of the main component has proper specific surface and pore structure, and has enough space for the epoxidation of ethylene to diffuse out the heat of reaction, and is favorable to desorbing the reaction product ethylene oxide in time to avoid deep oxidation to produce carbon dioxide as side product. German patent WO2021260138A1 provides a shaped catalyst body for the vapor phase oxidation of ethylene to ethylene oxide having a BET surface area of from 2 to 20m 2 And comprising silver and rhenium promoters deposited on a porous-alumina catalyst support, characterized in that the support has a calcination history of at least 1460 ℃, the catalyst support having a high surface area and a small amount of ethylene oxide isomerisation and/or decomposition activity. Chinese patent CN1009437B adopts alumina trihydrate with proper proportion to prepare the alumina powder with specific surface area of 0.2-2 m 2 And/g, the pore volume is larger than 0.5mL/g, wherein pores with the pore radius larger than 30 mu m account for less than 25 percent, and the selectivity of the catalyst can reach 83 to 84 percent when the catalyst is used for ethylene epoxidation reaction.
The addition of other components to alumina supports to improve the support and improve the performance of the silver catalyst is also an important research direction. In addition, the performance of the silver catalyst can also be improved by chemically treating the alumina carrier. German patent WO2021260185A1 provides a sheet-like catalyst support, characterized in that the alpha-alumina content is at least 85wt.%, the pore volume, as determined by mercury porosimetry, is at least 0.40ml/g, and the BET surface area is from 0.5 to 5.0m 2 The platelet-shaped catalyst support is an alpha-alumina catalyst support which has a high geometric accuracy and shows a high total pore volume, allowing impregnation with a large amount of silver, while showing a sufficiently large surface area to provide an optimal dispersion of the catalytically active species, in particular the metal species. European patent EP0150238B1 claims to improve the crushing strength and abrasion resistance of a support by using a small amount of barium aluminate or barium silicate binder in the manufacture of high purity, low surface alumina supports having a specific surface area of less than 0.3m 2 /g, made up ofThe catalyst activity and selectivity were relatively low. The alumina supports used in US4740493A, US4829043a and EP0501317A1 contain some amount of Ca, al, K, na soluble salts which purportedly reduce the rate of catalyst selectivity decline during use. US5384302a states that by pretreatment of α -Al 2 O 3 Reducing the Na, K, ca, al ion content in the carrier improves the crushing strength and abrasion resistance of the carrier. Korean patent KR102258044B1, which is a method for preparing a catalyst for producing high-yield ethylene oxide from ethylene by adjusting the metal crystal size by adding polyvinyl pyrrolidone, firstly dissolves a compound containing at least one first metal selected from Ag, pd and Pt in a solvent to form a solution, contains at least one compound of a first metal selected from cesium, rhenium, molybdenum, lithium, sodium, and then adds polyvinyl pyrrolidone (PVP) having a molecular weight of 20,000 to 55,000 to the catalyst precursor solution in an amount of 0.3 to 0.6wt% based on the catalyst precursor solution. EP0712334B1 provides a silver catalyst having improved stability by supporting an effective amount of silver, an auxiliary amount of an alkali metal, an auxiliary amount of magnesium, and an auxiliary amount of rhenium on a carrier comprising at least 85% alumina and 0.001-2% magnesium in the form of an oxide. U.S. Pat. No. 3,979,B1, U.S. Pat. No. 3, 5801259A, US5733842A incorporates alkaline earth metals, silicon, zirconium into alpha-Al 2 O 3 The silver catalyst is prepared by impregnating a carrier with silver, an alkali metal promoter, a rhenium promoter and a promoter thereof, and the patent indicates that alkaline earth metals, preferably calcium, strontium and barium salts are used together with zirconium compounds, and the influence of the addition of the two on the catalyst performance cannot be known. US5739075A prepares a silver catalyst from a treated carrier by depositing a promoter amount of a rare earth metal and another promoter amount of a metal salt (alkaline earth metal or group VIII transition metal) on the surface of an alumina carrier in advance, and then calcining the catalyst, and the evaluation result shows that the selectivity reduction rate of the catalyst is smaller than that of a catalyst sample which is not subjected to the pre-deposition treatment. CN1511632a found that a silver catalyst prepared by adding a heavy alkaline earth metal compound to an alumina raw material to prepare a carrier, impregnating a solution prepared from a silver compound, an organic amine and a specific auxiliary agent, and heat-treating the solution in an oxygen-containing mixed gas, was subjected to ethylene oxidation reactionThe activity and the selectivity are improved.
Although the above patent documents respectively adopt various methods to improve the alumina carrier, which brings about different improvements to the activity, stability and selectivity of the catalyst, the requirements for the catalyst performance are continuously increased along with the large-scale industrial application of the silver catalyst with high Re selectivity, and therefore, the performance of the silver catalyst is required to be continuously improved.
Disclosure of Invention
In view of the above-described prior art, the present inventors have conducted intensive studies in the field of silver catalysts, and as a result, have found that adding an appropriate amount of a chelating agent and nano manganese dioxide to a silver-ammonia solution can significantly improve the reactivity of a silver catalyst prepared therefrom.
The first aspect of the invention provides a silver catalyst for producing ethylene oxide by oxidizing ethylene, which comprises an alumina carrier, silver loaded on the alumina carrier, nano manganese dioxide and an auxiliary agent:
wherein, based on the total weight of the silver catalyst, the content of silver is 2 to 39 weight percent, preferably 10 to 35 weight percent; the content of the nano manganese dioxide is 0.001 to 0.5wt%, preferably 0.005 to 0.1wt%, and more preferably 0.01 to 0.05wt%.
In a second aspect, the invention provides a method for preparing a silver catalyst for producing ethylene oxide by oxidizing ethylene, comprising the following steps:
(1) Obtaining a silver ammonia solution, wherein the silver ammonia solution comprises a silver-containing compound, a chelating agent, nano manganese dioxide, an amine compound, water, an alkali metal auxiliary agent, an optional rhenium auxiliary agent and a co-auxiliary agent thereof;
(2) alpha-Al 2 O 3 And (3) immersing the carrier in the silver ammonia solution obtained in the step (1), and then carrying out solid-liquid separation and roasting to obtain the silver catalyst.
In a third aspect, the present invention provides a silver catalyst produced by the production method.
In a fourth aspect, the invention provides the use of the silver catalyst in the production of ethylene oxide by oxidation of ethylene.
Compared with the prior art, the invention has the following advantages: the porous alumina carrier is soaked in silver ammonia solution containing chelating agent and nanometer manganese dioxide, and the silver catalyst prepared from the porous alumina carrier has high reaction activity and is especially suitable for ethylene oxide production reaction by ethylene oxidation.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Detailed Description
The following describes specific embodiments of the present invention in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the invention, are not intended to limit the invention.
The invention provides a silver catalyst for producing ethylene oxide by ethylene oxidation, which comprises an alumina carrier, silver loaded on the alumina carrier, nano manganese dioxide and an auxiliary agent:
wherein, based on the total weight of the silver catalyst, the content of silver is 2 to 39 weight percent, preferably 10 to 35 weight percent; the content of the nano manganese dioxide is 0.001 to 0.5wt%, preferably 0.005 to 0.1wt%, and more preferably 0.01 to 0.05wt%.
According to the present invention, the diameter of the nano manganese dioxide is preferably 1 to 100 nm, and preferably 10 to 80 nm.
According to the present invention, preferably, the alumina carrier is porous α -Al 2 O 3 A vector in which alpha-A1 2 O 3 The content is more than or equal to 90 percent, and has the following characteristics: crushing strength is 20-200N/grain; the specific surface is 0.2-3.0 m 2 /g; the water absorption rate is more than or equal to 30 percent; the pore volume is 0.30-0.85 mL/g.
According to the invention, preferably, the promoter is an alkali metal promoter and optionally a rhenium promoter and co-promoters thereof; preferably, the content of the alkali metal auxiliary is 1 to 2000ppm, preferably 5 to 1500ppm, based on the total weight of the silver catalyst; the content of rhenium metal is 0 to 2000ppm, preferably 100 to 1000ppm in atomic terms; the content of the co-promoter of the rhenium promoter is 0 to 2000ppm, preferably 100 to 1000ppm in atomic terms.
According to the present invention, preferably, the silver catalyst is obtained by immersing the alumina carrier in a silver-ammonia solution, solid-liquid separation and calcination, wherein the silver-ammonia solution comprises a silver-containing compound, a chelating agent, nano manganese dioxide, an amine compound, water, an alkali metal auxiliary agent, an optional rhenium auxiliary agent and a co-auxiliary agent thereof; the chelating agent is at least one selected from ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid and aminotriacetic acid; the chelating agent is contained in an amount of 0.01 to 20.0wt%, preferably 0.05 to 5.0wt%, based on the total weight of the silver-ammonia solution.
The invention also provides a preparation method of the silver catalyst for producing ethylene oxide by oxidizing ethylene, which comprises the following steps:
(1) Obtaining a silver ammonia solution, wherein the silver ammonia solution comprises a silver-containing compound, a chelating agent, nano manganese dioxide, an amine compound, water, an alkali metal auxiliary agent, an optional rhenium auxiliary agent and a co-auxiliary agent thereof;
(2) alpha-Al 2 O 3 And (3) immersing the carrier in the silver ammonia solution obtained in the step (1), and then carrying out solid-liquid separation and roasting to obtain the silver catalyst.
According to the present invention, preferably, in the step (1), the diameter of the nano manganese dioxide is 1 to 100 nm, preferably 10 to 80 nm; the nano manganese dioxide is added in an amount such that the nano manganese dioxide content in the silver catalyst is 0.001 to 0.5wt%, preferably 0.005 to 0.1wt%, and more preferably 0.01 to 0.05wt%, based on the total weight of the silver catalyst.
According to the present invention, preferably, in step (1), the chelating agent is selected from at least one of ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid and aminotriacetic acid; the chelating agent is contained in an amount of 0.01 to 20.0wt%, preferably 0.05 to 5.0wt%, based on the total weight of the silver-ammonia solution.
According to the present invention, preferably, in the step (1), the amine compound is selected from at least one of ammonia water, ethylamine, N-propylamine, ethylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, N-dimethylformamide, ethanolamine and propanolamine; the silver-containing compound is at least one of silver acetate, silver nitrate and silver oxalate; the amine compound is added in an amount of 10 to 90wt% based on the total weight of the silver-ammonia solution, and the silver-containing compound is added in an amount such that the silver content in the silver catalyst is 2 to 39wt%, preferably 10 to 35wt% on an atomic basis.
According to the present invention, preferably, in step (1), the alkali metal auxiliary is selected from a compound of at least one of lithium, sodium, potassium, rubidium and cesium; the rhenium promoter is selected from at least one of rhenium oxide, perrhenic acid, cesium perrhenate, methyl rhenium trioxide (VII) and ammonium perrhenate; the co-promoter of the rhenium promoter is selected from at least one of manganese, chromium, sulfur, cobalt, molybdenum, nickel-containing salts or acid forms; the addition amount of the alkali metal auxiliary agent is such that the content of the alkali metal in the silver catalyst is 1 to 2000ppm, preferably 5 to 1500ppm, based on the total weight of the silver catalyst; the rhenium promoter is added in an amount such that the content of rhenium metal in the silver catalyst is 0 to 2000ppm, preferably 100 to 1000ppm, in atomic terms; the co-promoter of the rhenium promoter is added in such an amount that the content of the co-promoter of the rhenium promoter in the silver catalyst is 0 to 2000ppm, preferably 100 to 1000ppm in terms of atom.
In the present invention, the specific choice and amounts of the alkali metal promoter, rhenium promoter and co-promoter may be any conventional choice in the art.
According to the present invention, preferably, in the step (2), the time of the impregnation is 10 to 300 minutes, and the impregnation is preferably performed under a pressure of 100mmHg or less;
the solid-liquid separation comprises leaching and drying, and preferably the drying process after leaching is carried out in an air and/or inert gas atmosphere, the drying temperature is 50-120 ℃ and the time is 0.1-12 h.
In the invention, the impregnation in the step (2) can be carried out according to a conventional method in the field, the alumina carrier is completely impregnated in the solution obtained in the step (1), the impregnation time can be 10-300 minutes, the temperature of the impregnation solution is kept below 30 ℃, and the silver-containing compound and the like are prevented from being decomposed by heating and separated out in advance; the impregnation process can be accelerated by decompressing to below 100mmHg pressure, and the surface of the carrier is suitable for full infiltration without tiny bubbles and the inner and outer surfaces.
In the present invention, the solid-liquid separation in step (2) may include leaching and drying, preferably, the leaching process is performed while minimizing the excessive impregnation liquid adhering to the surface of the support, and the leaching process may be performed while removing the excessive dust in the alumina support, and drying is performed sufficiently until no significant change in the quality of the solid occurs.
According to the present invention, preferably, in the step (2), the firing is performed in air or a nitrogen-oxygen mixture gas having an oxygen content of not more than 21%; the roasting temperature is 100-600 ℃, preferably 150-500 ℃, and the roasting time is 0.5-120 minutes, preferably 1-30 minutes.
According to the present invention, preferably, the α -Al 2 O 3 The carrier is porous alpha-Al 2 O 3 A vector in which alpha-A1 2 O 3 The content is more than or equal to 90 percent, and has the following characteristics: crushing strength is 20-200N/grain; the specific surface is 0.2-3.0 m 2 /g; the water absorption rate is more than or equal to 30 percent; the pore volume is 0.30-0.85 mL/g.
The invention also provides a silver catalyst prepared by the preparation method.
The silver catalyst of the invention can be used for the application in the reaction of producing ethylene oxide by oxidizing ethylene. Specifically, in the presence of the silver catalyst, a mixed gas of ethylene and a gas such as oxygen is reacted in a fixed bed micro-tubular reactor.
The present invention will be further described with reference to examples, but the scope of the present invention is not limited to these examples.
Determination of catalyst Performance
The various silver catalysts of the present invention were tested for initial performance and stability using a laboratory reactor (hereinafter abbreviated as "micro-reverse") evaluation apparatus. The reactor used in the micro-reaction evaluation device is a stainless steel tube with an inner diameter of 4mm, and the reactor is placed in a heating sleeve. The catalyst loading volume was 1mL, and inert packing was placed in the lower portion to allow the catalyst bed to be located in the constant temperature zone of the heating mantle.
Determination of initial Activity and Selectivity
The activity and selectivity assay conditions used in the present invention are as follows:
composition of reaction gas (mol%)
When the above reaction conditions were reached, the reactor inlet and outlet gas compositions were continuously measured. After the volume shrinkage correction is carried out on the measurement result, the selectivity is calculated according to the following formula:
selectivity of
Where Δeo is the difference in the concentration of ethylene oxide in the outlet gas and the inlet gas ring, and the average of more than 10 sets of test data was taken as the test result on the same day.
The activity of the catalyst is measured by the reaction temperature at which a certain EO concentration is reached.
The carrier samples used in the examples and comparative examples were prepared from the same carrier formulation, and specific details are found in CN88100400.6, CN1634652a and US5063195, which are not described in detail herein.
Example 1
32.1g of ethylenediamine, 10.8g of ethanolamine, 3.5g of ethylenediamine tetraacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 10mg of manganese dioxide particles (diameter: 30 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 1.
Example 2
32.1g of ethylenediamine, 10.8g of ethanolamine, 3.5g of ethylenediamine tetraacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL by weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL by weight of rhenium atoms) and 10mg of manganese dioxide particles (diameter: 60 nm) were added in this order, and uniformly mixed to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 2.
Example 3
32.1g of ethylenediamine, 10.8g of ethanolamine, 3.5g of ethylenediamine tetraacetic acid and deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 20mg of manganese dioxide particles (diameter: 30 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 3.
Example 4
32.1g of ethylenediamine, 10.8g of ethanolamine, 3.5g of ethylenediamine tetraacetic acid and deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 20mg of manganese dioxide particles (diameter: 60 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 4.
Example 5
32.1g of ethylenediamine, 10.8g of ethanolamine, 10.5g of ethylenediamine tetraacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 10mg of manganese dioxide particles (diameter: 30 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 5.
Example 6
32.1g of ethylenediamine, 10.8g of ethanolamine, 10.5g of ethylenediamine tetraacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 10mg of manganese dioxide particles (diameter: 60 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 6.
Example 7
32.1g of ethylenediamine, 10.8g of ethanolamine, 10.5g of ethylenediamine tetraacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 20mg of manganese dioxide particles (diameter: 30 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 7.
Example 8
32.1g of ethylenediamine, 10.8g of ethanolamine, 10.5g of ethylenediamine tetraacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 20mg of manganese dioxide particles (diameter: 60 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 8.
Example 9
32.1g of ethylenediamine, 10.8g of ethanolamine, 3.5g of diethylenetriamine pentaacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 10mg of manganese dioxide particles (diameter: 60 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 2.
Example 10
32.1g of ethylenediamine, 10.8g of ethanolamine, 3.5g of aminotriacetic acid and 179.8g of deionized water are added into a glass beaker with stirring to obtain a mixed solution; slowly adding 72.2g of silver oxalate into the mixed solution, and keeping the temperature below 40 ℃ and continuously stirring to completely dissolve the silver oxalate; then, 2.25mL of cesium nitrate aqueous solution (concentration: 0.03995g/mL based on the weight of cesium atoms), 2.78mL of ammonium perrhenate aqueous solution (concentration: 0.0162g/mL based on the weight of rhenium atoms), 10mg of manganese dioxide particles (diameter: 60 nm) were added in this order, and mixed uniformly to prepare 300g of impregnating solution for use.
15g of carrier is taken, placed into a glass container capable of being vacuumized, and added with the impregnating solution, and the carrier is completely immersed. After evacuating to above 10mmHg and holding for about 15 minutes, the excess solution was leached off. Finally, the impregnated support sample was placed in an air stream at 350 ℃ and heated for about 2 minutes to produce silver catalyst example 2.
Comparative example 1
Comparative example 1 the procedure was the same as in example 1 except that the chelating agent and manganese dioxide particles were not added.
Comparative example 2
The diameter of manganese dioxide particles added in comparative example 2 was 290 nm, and the rest of the procedure was the same as in example 1.
Comparative example 3
In comparative example 3, no chelating agent was added, and the other steps were the same as in example 1.
The performance of the catalyst samples was measured under the aforementioned process conditions using a microreactor evaluation device for the silver catalysts of examples and comparative examples, and the evaluation results thereof are shown in table 1.
Table 1 silver catalysts comparative examples 1-3 and examples 1-10 day 6 evaluation results
As can be seen from Table 1, the initial reactivity of the silver catalyst samples prepared by the process of adding the chelating agent and nano-sized manganese dioxide particles to the silver-ammonia solution was significantly improved.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described.
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

Claims (15)

1. The silver catalyst for producing ethylene oxide by oxidizing ethylene is characterized by comprising an alumina carrier, silver loaded on the alumina carrier, nano manganese dioxide and an auxiliary agent:
wherein, based on the total weight of the silver catalyst, the content of silver is 2 to 39 weight percent, preferably 10 to 35 weight percent; the content of the nano manganese dioxide is 0.001 to 0.5wt%, preferably 0.005 to 0.1wt%, and more preferably 0.01 to 0.05wt%.
2. The silver catalyst for ethylene oxide production according to claim 1, wherein the diameter of the nano manganese dioxide is 1 to 100 nm, preferably 10 to 80 nm.
3. The silver catalyst for ethylene oxide production according to claim 1, wherein the alumina carrier is porous α -Al 2 O 3 A vector in which alpha-A1 2 O 3 The content is more than or equal to 90 percent, and has the following characteristicsThe sign is as follows: crushing strength is 20-200N/grain; the specific surface is 0.2-3.0 m 2 /g; the water absorption rate is more than or equal to 30 percent; the pore volume is 0.30-0.85 mL/g.
4. The silver catalyst for the production of ethylene oxide by the oxidation of ethylene according to claim 1, wherein the promoter is an alkali metal promoter and optionally a rhenium promoter and co-promoters thereof; preferably, the content of the alkali metal auxiliary is 1 to 2000ppm, preferably 5 to 1500ppm, based on the total weight of the silver catalyst; the content of rhenium metal is 0 to 2000ppm, preferably 100 to 1000ppm in atomic terms; the content of the co-promoter of the rhenium promoter is 0 to 2000ppm, preferably 100 to 1000ppm in atomic terms.
5. The silver catalyst for the production of ethylene oxide by oxidation of ethylene according to any one of claims 1 to 4, wherein the silver catalyst is obtained by immersing the alumina carrier in a silver ammonia solution, solid-liquid separation and calcination, the silver ammonia solution comprising a silver-containing compound, a chelating agent, nano manganese dioxide, an amine compound, water, an alkali metal auxiliary, an optional rhenium auxiliary and a co-auxiliary thereof; the chelating agent is at least one selected from ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid and aminotriacetic acid; the chelating agent is contained in an amount of 0.01 to 20.0wt%, preferably 0.05 to 5.0wt%, based on the total weight of the silver-ammonia solution.
6. The preparation method of the silver catalyst for producing ethylene oxide by ethylene oxidation is characterized by comprising the following steps:
(1) Obtaining a silver ammonia solution, wherein the silver ammonia solution comprises a silver-containing compound, a chelating agent, nano manganese dioxide, an amine compound, water, an alkali metal auxiliary agent, an optional rhenium auxiliary agent and a co-auxiliary agent thereof;
(2) alpha-Al 2 O 3 And (3) immersing the carrier in the silver ammonia solution obtained in the step (1), and then carrying out solid-liquid separation and roasting to obtain the silver catalyst.
7. The preparation method according to claim 6, wherein in the step (1), the diameter of the nano manganese dioxide is 1 to 100 nanometers, preferably 10 to 80 nanometers; the nano manganese dioxide is added in an amount such that the nano manganese dioxide content in the silver catalyst is 0.001 to 0.5wt%, preferably 0.005 to 0.1wt%, and more preferably 0.01 to 0.05wt%, based on the total weight of the silver catalyst.
8. The production process according to claim 6, wherein in the step (1), the chelating agent is selected from at least one of ethylenediamine tetraacetic acid, diethylenetriamine pentaacetic acid and aminotriacetic acid; the chelating agent is contained in an amount of 0.01 to 20.0wt%, preferably 0.05 to 5.0wt%, based on the total weight of the silver-ammonia solution.
9. The production process according to any one of claims 6 to 8, wherein in the step (1), the amine compound is selected from at least one of ammonia water, ethylamine, N-propylamine, ethylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, N-dimethylformamide, ethanolamine, and propanolamine; the silver-containing compound is at least one of silver acetate, silver nitrate and silver oxalate; the amine compound is added in an amount of 10 to 90wt% based on the total weight of the silver-ammonia solution, and the silver-containing compound is added in an amount such that the silver content in the silver catalyst is 2 to 39wt%, preferably 10 to 35wt% on an atomic basis.
10. The production process according to any one of claims 6 to 8, wherein in step (1), the alkali metal auxiliary is selected from a compound of at least one of lithium, sodium, potassium, rubidium and cesium; the rhenium promoter is selected from at least one of rhenium oxide, perrhenic acid, cesium perrhenate, methyl rhenium trioxide (VII) and ammonium perrhenate; the co-promoter of the rhenium promoter is selected from at least one of manganese, chromium, sulfur, cobalt, molybdenum, nickel-containing salts or acid forms; the addition amount of the alkali metal auxiliary agent is such that the content of the alkali metal in the silver catalyst is 1 to 2000ppm, preferably 5 to 1500ppm, based on the total weight of the silver catalyst; the rhenium promoter is added in an amount such that the content of rhenium metal in the silver catalyst is 0 to 2000ppm, preferably 100 to 1000ppm, in atomic terms; the co-promoter of the rhenium promoter is added in such an amount that the content of the co-promoter of the rhenium promoter in the silver catalyst is 0 to 2000ppm, preferably 100 to 1000ppm in terms of atom.
11. The production method according to any one of claims 6 to 8, wherein in the step (2), the time of the impregnation is 10 to 300 minutes, and the impregnation is preferably performed at a pressure of 100mmHg or less;
the solid-liquid separation comprises leaching and drying, and preferably the drying process after leaching is carried out in an air and/or inert gas atmosphere, the drying temperature is 50-120 ℃ and the time is 0.1-12 h.
12. The production method according to any one of claims 6 to 8, wherein in the step (2), the firing is performed in air or a nitrogen-oxygen mixture having an oxygen content of not more than 21%; the roasting temperature is 100-600 ℃, preferably 150-500 ℃, and the roasting time is 0.5-120 minutes, preferably 1-30 minutes.
13. The production method according to any one of claims 6 to 8, wherein the α -Al 2 O 3 The carrier is porous alpha-Al 2 O 3 A vector in which alpha-A1 2 O 3 The content is more than or equal to 90 percent, and has the following characteristics: crushing strength is 20-200N/grain; the specific surface is 0.2-3.0 m 2 /g; the water absorption rate is more than or equal to 30 percent; the pore volume is 0.30-0.85 mL/g.
14. A silver catalyst for producing ethylene oxide by oxidizing ethylene produced by the production method according to any one of claims 6 to 13.
15. Use of the silver catalyst for producing ethylene oxide by oxidizing ethylene according to any one of claims 1 to 5 and 14 in a reaction for producing ethylene oxide by oxidizing ethylene.
CN202210669156.3A 2022-06-14 2022-06-14 Silver catalyst for producing ethylene oxide by ethylene oxidation and preparation method and application thereof Pending CN117258786A (en)

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