Preparation method and application of a supported Ag metal catalyst
By preparing a molecular sieve-supported Ag catalyst, the problems of harsh reaction conditions and high catalyst cost in the existing 2-methylpropenol production were solved, and a low-cost, highly selective and stable catalyst was achieved, which is suitable for continuous reactors and improves mass transfer capacity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2022-11-24
- Publication Date
- 2026-06-05
AI Technical Summary
Existing methods for producing 2-methylpropenol suffer from problems such as harsh reaction conditions, numerous byproducts, high catalyst costs, the use of batch reactors, and the large-scale use of solvents, which limit their industrial application.
A molecular sieve-supported Ag catalyst was prepared using a top-down method. By optimizing the catalyst design and preparation method, continuous production of 2-methylpropenol was achieved in a fixed-bed reactor using hydrogen as a reducing agent.
It achieves a low-cost, highly selective, and stable catalyst suitable for continuous reactors, with mild reaction conditions, easy separation of the catalyst from the product, and improved mass transfer capability.
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Figure CN118059928B_ABST
Abstract
Description
Technical Field
[0001] This application relates to a method for preparing and applying an Ag metal catalyst supported on a molecular sieve, which belongs to the field of chemical engineering. Background Technology
[0002] 2-Methylpropenol is widely used in the production of polymer monomers, surfactants, synthetic resin additives, and polycarboxylic acid superplasticizers, and is an extremely important fine chemical.
[0003] Currently, there are four methods for producing 2-methylpropenol: 1. Chlor-alkali process, 2. Hydrogen transfer process, 3. Selective hydrogenation process, and 4. Dehydration process. Among these, the chlor-alkali process is the most widely used in actual industrial production. This method first generates isobutylene chloride through a substitution reaction between isobutylene and chlorine, followed by a hydroxyl substitution reaction under a strongly alkaline environment to produce 2-methylpropenol. Relatively speaking, the reaction conditions of this process are quite harsh, and the generation of a large amount of byproduct ether undoubtedly brings certain difficulties to the subsequent separation process. Furthermore, the use of chlorine places higher demands on safety and equipment investment.
[0004] The process of preparing methacrolein using isobutylene, a C4 byproduct from coal and petrochemical industries, as a raw material through oxidation is relatively mature and widely used in industry. This technology has led to the rapid development of processes for preparing methacrolein alcohol from methacrolein. The hydrogen transfer method refers to the transfer of the hydroxyl H atom from a small molecule alcohol to the carbonyl group of methacrolein under the action of a catalyst, generating methacrolein alcohol and the corresponding aldehyde or ketone. US Patent 4731488 reports a method for producing unsaturated alcohols using magnesium oxide as a catalyst and ethanol as a hydrogen donor. Although the conversion rate and selectivity for unsaturated alcohols in this method both exceed 90%, no related industrial reports have been found. Ye et al. (ACS Applied Nano Material, 2020, 3, 12260-12268) investigated the selective hydrogenation activity of Pt / Uio-66 for unsaturated aldehydes. Comparing the hydrogenation results under H2 atmosphere and with isopropanol as the hydrogen donor, they found that isopropanol resulted in higher conversion rates of unsaturated aldehydes and higher selectivity for unsaturated alcohols. Furthermore, the authors found that polar solvents are more favorable for the selectivity of unsaturated alcohols. Under the reaction conditions of isopropanol as a hydrogen donor, 150℃, and 12h, the conversion rate of cinnamaldehyde was 96.7%, and the selectivity of cinnamyl alcohol was 94.6%. Gong et al. (ChemCatChem, 2019, 12, 1019-1024) prepared activated carbon-supported CoOx@Co for the selective hydrogenation of a series of unsaturated aldehydes using an ultrasonic-assisted method and investigated the activity of various alcohols as hydrogen donors. The activity order was as follows: isopropanol > ethanol > 2-butanol > 2-pentanol > methanol. Currently, the two-step process for the production of methylpropenol from isobutylene, jointly developed by the Institute of Process Engineering, Chinese Academy of Sciences and Shandong Yidali Chemical Co., Ltd., has been industrialized. The first step of this process oxidizes isobutylene to methacrolein, and the second step uses a hydrogen transfer method to produce methylpropenol. Chinese patent CN103664526A discloses this technology in detail.
[0005] Compared to the three methods mentioned above, selective hydrogenation is a more efficient and environmentally friendly approach. Although some invention patents (CN102167657B, CN106631691A, CN107056566A) have reported on this method, the use of large amounts of solvents, batch reactors, and high catalyst preparation costs in the process have become prominent issues, which have hindered its practical industrial application. Summary of the Invention
[0006] This invention innovatively improves upon some shortcomings of existing technologies by designing a superior catalyst preparation method and rationally designing and optimizing the reaction process. A molecular sieve-supported Ag catalyst with better mass transfer performance is prepared using a top-down method for the selective hydrogenation of methacrolein. Continuous production of 2-methylpropenol is achieved using hydrogen as a reducing agent and a fixed-bed reactor.
[0007] This application focuses on catalysts and optimizes the design and preparation methods of catalysts to achieve a better method.
[0008] Molecular sieves have advantages such as low cost and availability, stable structure and large specific surface area, and are widely used in petrochemical, gas separation and other fields.
[0009] The Ag metal catalyst supported on molecular sieves involved in this application has good activity, high selectivity and strong stability, and has great potential industrial application value.
[0010] According to one aspect of this application, a method for preparing a supported Ag metal catalyst is provided, the method comprising the following steps:
[0011] The molecular sieve was impregnated with an alkaline solution and a silver source solution, and then dried and calcined to obtain the supported Ag metal catalyst.
[0012] Optionally, the alkaline solution is selected from at least one of sodium hydroxide solution, sodium bicarbonate solution, and sodium carbonate solution.
[0013] Optionally, the concentration of the alkaline solution is 0.1 to 0.9 M.
[0014] Optionally, the mass ratio of the alkaline solution to the molecular sieve is 5:1 to 20:1.
[0015] Optionally, the impregnation includes impregnating the molecular sieve with an alkaline solution first and then with a silver source solution, or impregnating the molecular sieve with a silver source solution first and then with an alkaline solution.
[0016] Optionally, the alkaline solution further includes an auxiliary agent selected from at least one of cetyltrimethylammonium bromide and poloxamer F127.
[0017] Optionally, the mass ratio of the auxiliary agent to the alkaline solution is 30:1 to 200:1.
[0018] Optionally, the silver source compound in the silver source solution is selected from at least one of silver nitrate, silver nitrite, and silver acetate.
[0019] Optionally, the mass ratio of the silver source solution to the molecular sieve is 5:1 to 20:1.
[0020] Optionally, the loading of Ag metal in the supported Ag metal catalyst is 5 to 25 wt%, and the mass of the Ag metal is based on the mass of Ag element.
[0021] Optionally, the molecular sieve is selected from at least one of NaY type molecular sieve, ZSM-5 molecular sieve, and ZSM-22 molecular sieve.
[0022] Optionally, the silica-to-alumina ratio of the molecular sieve is between 10 and 300.
[0023] Optionally, the drying temperature is 25–150°C, and the drying time is 24–48 hours.
[0024] Optionally, the drying temperature is selected from any value of 25°C, 50°C, 75°C, 100°C, 125°C, or 150°C, or a range between any two of the above.
[0025] Optionally, the drying time I is selected from any value among 24h, 36h, 40h, and 48h, or a range between any two of the above points.
[0026] Optionally, the calcination temperature is 150–950°C, and the calcination time is 1–5 hours.
[0027] Optionally, the roasting temperature is selected from any value of 150℃, 200℃, 300℃, 400℃, 500℃, 800℃, 900℃, 950℃ or a range between any two of the above points.
[0028] Optionally, the roasting time is selected from any value of 1h, 2h, 3h, 4h, 5h or a range between any two of the above points.
[0029] Optionally, the roasting atmosphere is selected from at least one of nitrogen atmosphere, air atmosphere, and argon atmosphere.
[0030] According to another aspect of this application, the application of the supported Ag metal catalyst prepared by the above-described preparation method in the selective hydrogenation of methacrolein to 2-methylpropenol is provided.
[0031] Optionally, the supported Ag metal catalyst is first pre-reduced under a reducing atmosphere, and then contacted with methacrolein and hydrogen to react and generate 2-methylpropenol.
[0032] Optionally, the reducing atmosphere is selected from a hydrogen atmosphere and / or a carbon monoxide atmosphere.
[0033] Optionally, the reducing atmosphere is selected from a hydrogen atmosphere.
[0034] Optionally, the pre-reduction time is 2h to 3h, and the pre-reduction temperature is 300 to 800℃.
[0035] Optionally, the pre-restore time is selected from any value among 2h, 2.5h, and 3h, or a range between any two of the above points.
[0036] Optionally, the pre-reduction temperature is selected from any value of 300℃, 400℃, 500℃, 600℃, 700℃, 800℃ or a range between any two of the above points.
[0037] Optionally, the molar ratio of hydrogen to methacrolein is 1:1 to 20:1.
[0038] Optionally, the mass hourly space velocity (HHSV) of the methacrolein is 0.5–5 h⁻¹. -1 .
[0039] Optionally, the reaction pressure is 0.1 to 5.0 MPa.
[0040] Optionally, the reaction temperature is 50–250°C.
[0041] Optionally, the molar ratio of hydrogen to methacrolein is selected from any value among 1:1, 5:1, 10:1, 15:1, 20:1, or a range between any two of the above.
[0042] Optionally, the mass hourly space velocity (MSV) of the methacrolein is selected from 0.5 h⁻¹. -1 1h -1 2h -1 3h -1 4h -1 5h -1 Any value in the range or any two points mentioned above.
[0043] As a specific implementation method, the present invention is achieved through the following technical solution:
[0044] The first solution adopted in this invention:
[0045] (1) Prepare an aqueous solution with a concentration of 0.1 to 0.9 M using one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia.
[0046] (2) Add one of the ZSM-5 molecular sieves with a silicon-to-aluminum ratio of 10 to 300 to the above solution, with the mass ratio of the solution to the molecular sieve being between 5 and 20.
[0047] (3) Stir the above solution vigorously and keep the temperature between 30 and 90°C for 10 to 120 minutes.
[0048] (4) Centrifuge and wash the treated sample 7 times and filter it.
[0049] (5) Dry the filtered sample at 25-150℃ for 24 hours.
[0050] (6) The sample is roasted in one or more of nitrogen, argon and air at a temperature between 150 and 950°C for a time between 1 and 5 hours.
[0051] (7) Prepare an aqueous solution of silver nitrate and immerse it in the above sample. The metal loading is between 5 and 15 wt.%.
[0052] (8) The sample was dried at 25-150℃ for 24 hours.
[0053] (9) The sample is roasted in one or more of nitrogen, argon and air at a temperature between 150 and 950°C for a time between 1 and 5 hours.
[0054] (10) The calcined catalyst is pressed into tablets and crushed into 20-40 mesh particles, and then loaded into a fixed bed reactor to reduce the catalyst in situ using hydrogen in the range of 300-750°C.
[0055] (11) The reaction temperature is between 50 and 250°C, and the space velocity is between 0.5 and 5 h⁻¹. -1 The ratio of hydrogen to methacrolein is between 1 and 20.
[0056] The second solution adopted in this invention:
[0057] (1) Prepare an aqueous solution with a concentration of 0.1 to 0.9 M using one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia water, and add 0.5 g of CTAB and / or poloxamer F127 to it.
[0058] (2) Add one type of NaY molecular sieve with a silicon-to-aluminum ratio of 1 to 15 to the above solution, and the mass ratio of the solution to the molecular sieve is between 5 and 20.
[0059] (3) Stir the above solution vigorously and keep the temperature between 30 and 90°C for 10 to 120 minutes.
[0060] (4) Centrifuge and wash the treated sample 7 times and filter it.
[0061] (5) Dry the filtered sample at 25-150℃ for 24 hours.
[0062] (6) The sample is roasted in one or more of nitrogen, argon and air at a temperature between 150 and 950°C for a time between 1 and 5 hours.
[0063] (7) Prepare an aqueous solution of silver nitrate and immerse it in the above sample. The metal loading is between 5 and 15 wt.%.
[0064] (8) The sample was dried at 25-150℃ for 24 hours.
[0065] (9) The sample is roasted in one or more of nitrogen, argon and air at a temperature between 150 and 950°C for a time between 1 and 5 hours.
[0066] (10) The calcined catalyst is pressed into tablets and crushed into 20-40 mesh particles, and then loaded into a fixed bed reactor to reduce the catalyst in situ using hydrogen in the range of 300-750°C.
[0067] (11) The reaction temperature is between 50 and 250°C, and the space velocity is between 0.5 and 5 h⁻¹. -1 The ratio of hydrogen to methacrolein is between 1 and 20.
[0068] The third solution adopted in this invention:
[0069] (1) Prepare an aqueous solution with a concentration of 0.1 to 0.9 M using one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia water, and add 0.5 g of CTAB and / or poloxamer F127 to it.
[0070] (2) Add one of the ZSM-5 molecular sieves with a silicon-to-aluminum ratio of 10 to 300 to a silver nitrate solution. The mass ratio of the solution to the molecular sieve is between 5 and 20, and the mass of silver nitrate is added between 5 and 15 wt.% depending on the loading.
[0071] (3) Stir the above solution vigorously and keep the temperature between 30 and 90°C, and slowly add the alkaline solution from (1) dropwise. After the addition is complete, keep it between 10 and 120 minutes.
[0072] (4) Centrifuge and wash the treated sample 7 times and filter it.
[0073] (5) Dry the filtered sample at 25-150℃ for 24 hours.
[0074] (6) The sample is roasted in one or more of nitrogen, argon and air at a temperature between 150 and 950°C for a time between 1 and 5 hours.
[0075] (7) The calcined catalyst is pressed into tablets and crushed into 20-40 mesh particles, and then loaded into a fixed bed reactor to reduce the catalyst in situ using hydrogen in the range of 300-750°C.
[0076] (8) The reaction temperature is between 50 and 250°C, and the space velocity is between 0.5 and 5 h⁻¹. -1 The ratio of hydrogen to methacrolein is between 1 and 20.
[0077] The present invention adopts the fourth solution:
[0078] (1) Prepare an aqueous solution with a concentration of 0.1 to 0.9 M using one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia water, and add 0.5 g of CTAB and / or poloxamer F127 to it.
[0079] (2) Add one of the ZSM-22 molecular sieves with a silicon-to-aluminum ratio of 10 to 300 to a silver nitrate solution. The mass ratio of the solution to the molecular sieve is between 5 and 20, and the mass of silver nitrate is added between 5 and 15 wt.% depending on the loading.
[0080] (3) Stir the above solution vigorously and keep the temperature between 30 and 90°C, and slowly add the alkaline solution from (1) dropwise. After the addition is complete, keep it between 10 and 120 minutes.
[0081] (4) Centrifuge and wash the treated sample 7 times and filter it.
[0082] (5) Dry the filtered sample at 25-150℃ for 24 hours.
[0083] (6) The sample is roasted in one or more of nitrogen, argon and air at a temperature between 150 and 950°C for a time between 1 and 5 hours.
[0084] (7) The calcined catalyst is pressed into tablets and crushed into 20-40 mesh particles, and then loaded into a fixed bed reactor to reduce the catalyst in situ using hydrogen in the range of 300-750°C.
[0085] (8) The reaction temperature is between 50 and 250°C, and the space velocity is between 0.5 and 5 h⁻¹. -1 The ratio of hydrogen to methacrolein is between 1 and 20.
[0086] The beneficial effects that this application can produce include:
[0087] Compared to noble metal catalysts such as Pt, Pd, and Ir, the Ag catalyst supported on molecular sieves has a relatively low preparation cost, high reactivity, high selectivity for the target product, and extremely strong stability. It is produced using a continuous reactor, and the reaction is carried out under solvent-free and relatively mild reaction conditions. The heterogeneous catalyst facilitates separation from the product, and the mass transfer capacity of the catalytic system is effectively improved by post-treatment of the molecular sieve, making the reaction easier to carry out. Attached Figure Description
[0088] Figure 1 This is a graph showing the characterization results of nitrogen adsorption-desorption of the catalyst after calcination in Example 1 of this application.
[0089] Figure 2 The figure shows the nitrogen adsorption-desorption characterization results of the catalyst after comparative calcination in this application. Detailed Implementation
[0090] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0091] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0092] Conversion rate = 1 - Amount of unconverted reactants / Total amount of reactants.
[0093] Selectivity = Amount of product / Amount of reactants converted.
[0094] Example 1
[0095] Mix 10g NaOH with 100ml water to prepare a solution and store it in a polytetrafluoroethylene bottle. Place the solution in a water bath at a constant temperature of 80℃. Weigh 10g of ZSM-5 molecular sieve (silicon-to-aluminum ratio 25), add it to the solution, maintain for 40 minutes, then centrifuge and wash the sample 7 times. Place the filtered sample in a 100℃ oven and dry for 24 hours. Then calcine the dried sample at 600℃ for 5 hours under a nitrogen atmosphere. Dissolve 1g of silver nitrate in 4ml of deionized water. Weigh 3g of the treated molecular sieve sample and impregnate the molecular sieve with the silver nitrate solution. Let it stand at 25℃ for 24 hours, then dry at 120℃ for 24 hours, and finally calcine at 500℃ for 5 hours. Compress and crush the calcined catalyst into 20-40 mesh particles, load them into a fixed-bed reactor, and reduce the catalyst in situ using hydrogen at 750℃. After the fixed-bed reactor is cooled to 180°C, methacrolein is introduced at a space velocity of 2 h⁻¹. -1 The ratio of hydrogen to methacrolein was 10, and the selectivity of methacrolein and isobutyraldehyde is shown in Table 1. The nitrogen adsorption-desorption characterization results of the calcined catalyst are as follows: Figure 1 As shown, from Figure 1 It can be seen that the catalyst treated with alkali exhibits a distinct mesoporous structure.
[0096] Example 2
[0097] Mix 10g NaOH, 0.5g CTAB, and 100ml water to prepare a solution and store it in a PTFE bottle. Place the solution in a water bath at a constant temperature of 80℃. Weigh 10g of NaY molecular sieve (silicon-to-aluminum ratio 10) and add it to the solution. Maintain for 40 minutes, then centrifuge and wash the sample 7 times. Place the filtered sample in a 100℃ oven and dry for 24 hours. Then, calcine the dried sample at 600℃ for 5 hours under a nitrogen atmosphere. Dissolve 1g of silver nitrate in 4ml of deionized water. Weigh 3g of the treated molecular sieve sample and impregnate it with the silver nitrate solution. Let it stand at 25℃ for 24 hours, then dry at 120℃ for 24 hours, and finally calcine at 500℃ for 5 hours. Compress and crush the calcined catalyst into 20-40 mesh particles, and load it into a fixed-bed reactor for in-situ reduction using hydrogen at 750℃. After the fixed-bed reactor is cooled to 180°C, methacrolein is introduced at a space velocity of 2 h⁻¹. -1 The ratio of hydrogen to methacrolein is 10, and the selectivity of methacrolein and isobutyraldehyde is shown in Table 1.
[0098] Example 3
[0099] Dissolve 4g sodium carbonate, 6g sodium hydroxide, and 0.5g F127 in 100ml of water to prepare solution A. Add 10g of ZSM-5 molecular sieve with a silicon-to-aluminum ratio of 30 and 1g silver nitrate to a polytetrafluoroethylene bottle containing 100ml of water and maintain a constant temperature of 60℃. Slowly add solution A to the molecular sieve suspension using a constant flow pump and maintain the temperature for 60min. Centrifuge and wash the treated sample 7 times and filter. Dry the filtered sample at 120℃ for 24h. Finally, calcine at 500℃ for 5h. Press the calcined catalyst into tablets, crush them to 20-40 mesh, and load them into a fixed-bed reactor. Reduce the catalyst in situ using hydrogen at 750℃. After the fixed-bed reactor cools to 180℃, purge with methacrolein at a space velocity of 2h. -1 The ratio of hydrogen to methacrolein is 10, and the selectivity of methacrolein and isobutyraldehyde is shown in Table 1.
[0100] Example 4
[0101] Dissolve 4g sodium carbonate, 6g sodium hydroxide, and 0.5g F127 in 100ml of water to prepare solution A. Add 10g of ZSM-22 molecular sieve with a silicon-to-aluminum ratio of 30 and 1g silver nitrate to a polytetrafluoroethylene bottle containing 100ml of water and maintain a constant temperature of 60℃. Slowly add solution A to the molecular sieve suspension using a constant flow pump and maintain the temperature for 60min. Centrifuge and wash the treated sample 7 times and filter. Dry the filtered sample at 120℃ for 24h. Finally, calcine at 500℃ for 5h. Press the calcined catalyst into tablets, crush them to 20-40 mesh, and load them into a fixed-bed reactor. Reduce the catalyst in situ using hydrogen at 750℃. After the fixed-bed reactor cools to 180℃, purge with methacrolein at a space velocity of 2h. -1 The ratio of hydrogen to methacrolein is 10, and the selectivity of methacrolein and isobutyraldehyde is shown in Table 1.
[0102] Comparative Example
[0103] Dissolve 1g of silver nitrate in 4ml of deionized water. Weigh 3g of untreated ZSM-5 molecular sieve (silicon-to-aluminum atomic ratio 30) sample and impregnate the molecular sieve with the silver nitrate solution. Let stand at 25℃ for 24h, then dry at 120℃ for 24h, and finally calcine at 500℃ for 5h. Compress and crush the calcined catalyst into 20-40 mesh particles, and load them into a fixed-bed reactor. Reduce the catalyst in situ using hydrogen at 750℃. After the fixed-bed reactor cools to 180℃, purge with methacrolein at a space velocity of 2h. -1 The ratio of hydrogen to methacrolein is 10, and the selectivity of methacrolein and isobutyraldehyde is shown in Table 1.
[0104] Table 1 shows the activity evaluation results in the examples.
[0105]
[0106]
[0107] As can be seen from Table 1, Example 3 exhibits good activity and selectivity for the target product in the specific preparation method described above.
[0108] Figure 1 The catalyst exhibits a significant hysteresis loop, and Figure 2 The change is not obvious, indicating that the pore structure of the catalyst has changed. Figure 1 The catalyst exhibits more mesoporous structures.
[0109] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. An application of selective hydrogenation of methacrolein to prepare 2-methylpropenol, characterized in that, The supported Ag metal catalyst was first pre-reduced under a reducing atmosphere, and then reacted with methacrolein and hydrogen to produce 2-methylpropenol. The supported Ag metal catalyst was obtained by the following preparation steps: The molecular sieve was impregnated with an alkaline solution and a silver source solution, and then dried and calcined to obtain the supported Ag metal catalyst. The alkaline solution is selected from at least one of sodium hydroxide solution, sodium bicarbonate solution, and sodium carbonate solution; The concentration of the alkaline solution is 0.1~0.9M; The alkaline solution also includes an auxiliary agent selected from at least one of cetyltrimethylammonium bromide and poloxamer F127; The loading amount of Ag metal in the supported Ag metal catalyst is 5~25 wt%, and the mass of the Ag metal is based on the mass of Ag element; The molecular sieve is selected from at least one of NaY type molecular sieve, ZSM-5 molecular sieve, and ZSM-22 molecular sieve.
2. The application according to claim 1, characterized in that, The mass ratio of the alkaline solution to the molecular sieve is 5:1 to 20:
1.
3. The application according to claim 1, characterized in that, The impregnation includes impregnating the molecular sieve with an alkaline solution first and then with a silver source solution, or impregnating the molecular sieve with a silver source solution first and then with an alkaline solution.
4. The application according to claim 1, characterized in that, The mass ratio of the auxiliary agent to the alkaline solution is 30:1 to 200:
1.
5. The application according to claim 1, characterized in that, The silver source compound in the silver source solution is selected from at least one of silver nitrate, silver nitrate, and silver acetate.
6. The application according to claim 1, characterized in that, The mass ratio of the silver source solution to the molecular sieve is 5:1 to 20:
1.
7. The application according to claim 1, characterized in that, The silica-to-alumina ratio of the molecular sieve is between 10 and 300.
8. The application according to claim 1, characterized in that, The drying temperature is 25~150 ℃, and the drying time is 24~48 h.
9. The application according to claim 1, characterized in that, The roasting temperature is 150~950 ℃, and the roasting time is 1~5 h.
10. The application according to claim 1, characterized in that, The roasting atmosphere is selected from at least one of nitrogen atmosphere, air atmosphere, and argon atmosphere.
11. The application according to claim 1, characterized in that, The reducing atmosphere is selected from hydrogen atmosphere and / or carbon monoxide atmosphere.
12. The application according to claim 1, characterized in that, The pre-reduction time is 2 h to 3 h, and the pre-reduction temperature is 300 to 800 ℃.
13. The application according to claim 1, characterized in that, The molar ratio of hydrogen to methacrolein is 1:1 to 20:1; The mass hourly space velocity (MSV) of the methacrolein is 0.5–5 h⁻¹. -1 ; The reaction pressure is 0.1~5.0 MPa; The reaction temperature is 50~250 ℃.