Method for removing ethylene at low temperature

Abstract

The invention discloses a method for removing ethylene at a low temperature, which comprises the following steps: contacting an ethylene-containing raw material with a pre-reduced ZSM-5 type catalyst to generate an ethylene oxidation reaction; the temperature of the ethylene oxidation reaction is-25 DEG C to 35 DEG C; the ZSM-5 type catalyst comprises a carrier and an active component; the carrier is a ZSM-5 type hierarchical pore molecular sieve; the active component comprises an active element, and the active element is selected from at least one of Pt, Pd, Ag, Au, Ru, Rh, Os and Ir; the ZSM-5 type hierarchical pore molecular sieve is provided with micropores and mesopores. The low-temperature ethylene removal catalyst provided by the invention is not only high in cost benefit and excellent in efficiency, but also shows extremely high removal efficiency and durability especially in the application of catalytic removal of trace ethylene at low temperature, and indicates wide application potential.

Description

Technical Field

[0001] The present application relates to a method for removing ethylene at low temperature, belonging to the field of postharvest preservation of agricultural products. Background Art

[0002] With the growth of the population and the change of consumption patterns, the postharvest preservation of agricultural products has become an important link in the food supply chain. Ethylene, as a plant hormone, is often naturally produced during the ripening process of agricultural products and can accelerate the ripening process of other unripe agricultural products. However, this property of ethylene may cause premature ripening and decay of agricultural products during logistics and storage, resulting in economic losses and waste of resources. In the global food market, maintaining the freshness of agricultural products and extending the shelf life have become core issues in supply chain management. Effective ethylene management strategies can significantly improve transportation efficiency, reduce losses caused by over-ripening, and are also crucial for ensuring that consumers can enjoy high-quality agricultural products. Therefore, developing a technology that can remove or control ethylene under mild environmental and cost-effective conditions is an urgent challenge for the modern agricultural product supply chain.

[0003] The development of catalytic technologies and catalytic materials has attracted attention to the complete oxidation of ethylene. Previous studies used titanium-based materials for the photocatalytic oxidation of ethylene in continuous reactors, but the operating conditions of these reactors were complex and the efficiency of removing ethylene at room temperature was not high. At the same time, although ozone is a strong oxidant, excessive ozone may cause secondary pollution and requires additional chemical processes to be effectively removed, thus increasing the cost. There are also some solid thermal catalysts that show oxidation activity towards ethylene above room temperature. To overcome these limitations, zeolite-based catalysts such as ZSM-5 have been developed, which have attracted wide attention in the field of catalysts due to their unique pore structure and acidic sites. However, ZSM-5 is limited by its relatively low specific surface area and pore volume in some applications. Therefore, the hierarchical pore structure of ZSM-5 proposed in the present invention promotes the effective diffusion of substances inside the catalyst, reduces diffusion limitations, increases the reaction rate, enhances the stability and service life of the catalyst. In addition, the preparation process of this catalyst also takes into account cost-effectiveness and environmental impact, providing a new solution for the postharvest preservation of agricultural products. Summary of the Invention

[0004] One aspect of the present application provides a method for removing ethylene at low temperature, the method comprising:

[0005] Contacting a raw material containing ethylene with a pre-reduced ZSM-5 type catalyst to carry out an ethylene oxidation reaction;

[0006] The temperature of the ethylene oxidation reaction is -25°C to 35°C;

[0007] The ZSM-5 type catalyst comprises a carrier and an active component;

[0008] The carrier is a ZSM-5 type hierarchical pore molecular sieve;

[0009] The active component includes active elements, and the active elements are selected from at least one of Pt, Pd, Ag, Au, Ru, Rh, Os and Ir;

[0010] The ZSM-5 type hierarchical pore molecular sieve has micropores and mesopores.

[0011] Optionally, the temperature of the ethylene oxidation reaction is independently selected from any value of -25°C, -15°C, 0°C, 15°C, 25°C, 35°C or any range value between any two of the above.

[0012] Optionally, in the ZSM-5 type catalyst, the mass percentage of the active component in the carrier is 0.01 wt% to 10 wt%, where the mass of the active component is calculated based on the mass of the active elements.

[0013] Optionally, the ratio of the active component to the carrier is 0.01 to 7 wt%.

[0014] Optionally, the mass percentage of the active component in the carrier is independently selected from any value of 0.01 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt% or any range value between any two of the above.

[0015] Optionally, the specific surface area of the micropores is 100 - 300 m 2 / g, and the volume of the micropores is 0.05 - 0.15 cm 3 / g;

[0016] Optionally, the specific surface area of the mesopores is 200 - 550 m 2 / g, the volume of the mesopores is 0.3 - 0.8 cm 3 / g, and the pore diameter of the mesopores is 2 - 8 nm.

[0017] Optionally, the preparation method of the ZSM-5 type catalyst includes:

[0018] (1) Treating the ZSM-5 molecular sieve in an alkaline solution containing a surfactant, stirring I, drying I, and calcining I to obtain the molecular sieve after alkali treatment;

[0019] (2) Performing ammonium exchange on the molecular sieve after alkali treatment obtained in (1), drying II, and calcining II to obtain the ZSM-5 type hierarchical pore molecular sieve;

[0020] (3) Impregnate an aqueous solution containing a precursor of the active component onto the ZSM-5 type hierarchical pore molecular sieve described in step (2) in an equal volume, dry III, and calcine III to obtain a ZSM-5 type catalyst.

[0021] As a specific embodiment, the preparation method includes: subjecting the as-received molecular sieve to alkali treatment to obtain a hierarchical pore molecular sieve as the catalyst support; the noble metal active component on the support is loaded onto the support by an impregnation method. Among them, the preparation method of the supported hierarchical pore molecular sieve includes: placing the molecular sieve to be treated in a solution containing an alkali for treatment, stirring, followed by centrifugal washing, drying, and calcining to obtain a hierarchical pore molecular sieve support after alkali treatment.

[0022] This catalyst has excellent activity, selectivity, and stability for the low-temperature ethylene removal reaction system.

[0023] Optionally, in step (1), the ZSM-5 molecular sieve is a commercial microporous molecular sieve.

[0024] Optionally, in step (1), the silicon-aluminum ratio of the ZSM-5 molecular sieve is Si / Al = 20 to 1000.

[0025] In this application, the silicon-aluminum ratio refers to the molar ratio of silicon element to aluminum element.

[0026] Optionally, the alkaline substance in the alkali solution is selected from at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate;

[0027] In the alkali solution, the concentration of the alkaline substance is 0.1 to 3 mol / L.

[0028] Optionally, in the alkali solution, the concentration of the alkaline substance is 0.5 to 1 mol / L.

[0029] Optionally, the concentration of the alkaline substance is independently selected from any value of 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 2 mol / L, 3 mol / L or any range value between any two of the above.

[0030] As a specific embodiment, the microporous molecular sieve is ZSM-5, the alkali is sodium hydroxide, and the silicon-aluminum ratio of the molecular sieve is Si / Al = 30 to 300.

[0031] Optionally, the surfactant is selected from at least one of dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide;

[0032] In the alkali solution, the concentration of the surfactant is 0.05 to 0.20 mol / L.

[0033] Optionally, the concentration of the surfactant is independently selected from any value of 0.05 mol / L, 0.10 mol / L, 0.15 mol / L, 0.20 mol / L or any range value between any two of the above.

[0034] Optionally, the solid-liquid ratio of the ZSM-5 molecular sieve to the alkali solution is 1:10 to 50 g / ml.

[0035] Optionally, the solid-liquid ratio of the ZSM-5 molecular sieve to the alkali solution is 1:30 g / ml.

[0036] Optionally, the temperature of the first stirring is 30 to 90 °C, and the time of the first stirring is 10 to 60 min;

[0037] Optionally, the temperature of the first stirring is 50 to 85 °C, and the time of the first stirring is 20 to 40 min;

[0038] Optionally, the temperature of the first stirring is independently selected from any value of 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C or any range value between any two of the above.

[0039] Optionally, the time of the first stirring is independently selected from any value of 10 min, 20 min, 30 min, 40 min, 50 min, 60 min or any range value between any two of the above.

[0040] Optionally, the temperature of the first drying is 60 to 120 °C, and the time of the first drying is 10 to 24 hours;

[0041] The temperature of the first calcination is 500 to 700 °C, and the time of the first calcination is 2 to 8 h.

[0042] Preferably, the temperature of the first drying is 120 °C, the time of the first drying is 12 h, the temperature of the first calcination is 550 °C, and the time of the first calcination is 5 h.

[0043] Optionally, the temperature of the second drying is 100 to 120 °C, and the time of the second drying is 10 to 24 hours;

[0044] Optionally, the temperature of the second calcination is 400 to 600 °C, and the time of the second calcination is 2 to 5 hours.

[0045] Preferably, the temperature of the first drying is 120 °C, the time of the first drying is 12 h, the temperature of the first calcination is 550 °C, and the time of the first calcination is 3 h.

[0046] In step (3), the active component precursor is selected from at least one of H2PtCl6, PdCl, AgNO, RuCl, RhCl, OsCl, and IrCl;

[0047] Optionally, the impregnation time is 12 to 24 h.

[0048] Optionally, the impregnation time is independently selected from any value of 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h or any range value between any two of the above.

[0049] Optionally, the drying III temperature is 60 to 120 °C, and the drying III time is 10 to 24 h;

[0050] The calcination III temperature is 500 to 1000 °C, and the calcination III time is 2 to 8 h.

[0051] Preferably, the drying III temperature is 120 °C, the drying III time is 12 h, the calcination III temperature is 600 to 900 °C, and the calcination III time is 3 to 5 h.

[0052] Optionally, the calcination III temperature is independently selected from any value of 500 °C, 600 °C, 650 °C, 700 °C, 750 °C, 800 °C, 850 °C, 900 °C, 1000 °C or any range value between any two of the above.

[0053] As a specific implementation manner, in step (3), the active metal component is loaded onto the carrier by an impregnation method, including: impregnating the aqueous solution of the loading substance onto the product of the ZSM-5 hierarchical pore carrier in an equal volume, stirring, drying, and calcining to obtain the target catalyst product.

[0054] Optionally, the conditions for pre-reduction include:

[0055] The atmosphere for pre-reduction is H2.

[0056] Optionally, the pre-reduction time is 1 to 3 h, and the pre-reduction temperature is 200 to 600 °C.

[0057] Optionally, the pre-reduction temperature is independently selected from any value of 200 °C, 300 °C, 350 °C, 400 °C, 450 °C, 500 °C, 550 °C, 600 °C or any range value between any two of the above.

[0058] Optionally, the pre-reduction time is independently selected from any value of 1 h, 1.5 h, 2 h, 2.5 h, 3 h or any range value between any two of the above.

[0059] Optionally, in the raw material, the concentration of ethylene is 0.1 ppm to 1000 ppm.

[0060] Optionally, in the raw material, the concentration of ethylene is 0.1 ppm to 200 ppm.

[0061] Optionally, the space velocity of the raw material is 5000 to 10000 h -1 。

[0062] Optionally, the space velocity of the raw material is 5000 to 8000 h -1 。

[0063] Optionally, the pressure of the reaction is 0.1 to 0.5 MPa.

[0064] Optionally, the pressure of the reaction is independently selected from any value of 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa or any range value between any two of the above.

[0065] As a specific implementation manner, the reaction is carried out in a small fixed-bed continuous flow reaction device. Weigh 0.4 g of the ZSM-5 hierarchical pore catalyst and place it in a steel reaction tube (inner diameter 5 mm), and adjust the flow rate of ethylene gas to 25 ml / min.

[0066] The beneficial effects that this application can produce include:

[0067] 1) The improved catalyst of the present invention has excellent reaction performance and good stability for the low-temperature removal of ethylene, with a fast reaction rate, high yield, and good catalyst regeneration performance.

[0068] 2) This application provides a preparation method of the above catalyst. The preparation process is simple, highly operable, and can be used for large-scale industrial production

[0069] 3) The low-temperature ethylene removal catalyst provided by this application not only has high cost-effectiveness and good efficiency, but also shows extremely high removal efficiency and durability in the application of catalytically removing trace ethylene at low temperatures, indicating its broad application potential. Description of the Drawings

[0070] Figure 1 It is the nitrogen physical adsorption-desorption curve ((a) figure) and pore size distribution curve ((b) figure) of Sample 10 in Example 10 of this application # 。 Detailed Embodiments

[0071] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.

[0072] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0073] The analysis methods in the embodiments of this application are as follows:

[0074] Characterization of specific surface area and pore size distribution

[0075] A Micromeritics ASAP 2460 physical adsorption analyzer was used to characterize the specific surface area and pore size distribution.

[0076] The analysis conditions for specific surface area and pore volume were as follows: 0.1 g of the catalyst was loaded into a quartz adsorption tube and vacuum-treated at 350 °C for 12 h to remove the water and impurities adsorbed by the molecular sieve. A nitrogen adsorption / desorption experiment was carried out at a temperature of 77.4 K. The Brunauer-Emmett-Teller (BET) equation was used to calculate the micropore specific surface area of the sample, and the t-plot method was used to calculate the micropore specific surface area, micropore volume, mesopore specific surface area, and mesopore volume of the molecular sieve sample. The BJH method was used to obtain the pore size distribution of the sample.

[0077] Characterization by gas chromatography

[0078] Product analysis was carried out using an Agilent 7890B gas chromatograph for on-line analysis. The FID detector was used to analyze organic compounds (chromatographic column: Agilent HP-PLOT U), and the TCD detector was used to analyze CO2 (chromatographic column: 5A molecular sieve).

[0079] As an implementation method, the preparation method of the catalyst for low-temperature ethylene removal was carried out according to the following steps:

[0080] (1) ZSM-5 molecular sieve was added to an alkaline solution containing a surfactant, stirred at 50-85 °C for 20-40 min, centrifuged, washed, dried, and calcined;

[0081] (2) The sample obtained in (1) was subjected to ammonium exchange and calcined to obtain a ZSM-5 type hierarchical pore molecular sieve.

[0082] (3) An aqueous solution of the load was impregnated onto the product obtained in step (2) in an equal volume, stirred, dried, and calcined to obtain the target catalyst product.

[0083] (4) A small fixed-bed continuous flow reaction evaluation device was used. 0.4 g of the catalyst was weighed and placed in a steel reaction tube (inner diameter 5 mm). The flow rate of 100 ppm ethylene gas was adjusted to 25 ml / min for the complete oxidation reaction of ethylene

[0084] Preparation of the catalyst in Example 1

[0085] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 18 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio is 35), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 1; take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 1, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine it at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.0159 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, place the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 1 # , and the loading amount of the metal active component Pt is 0.1 wt%.

[0086] Preparation of the catalyst in Example 2

[0087] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio is 35), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 2; take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 2, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine it at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.0159 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, place the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 2 # , and the loading amount of the metal active component Pt is 0.1 wt%.

[0088] Preparation of the catalyst in Example 3

[0089] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of tetradecyltrimethylammonium bromide (C 14An aqueous solution with a concentration of 0.05 mol / L of TAB is heated in a water bath to 65 °C. 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) is added, and it is stirred at 65 °C for 30 min. Then, it is centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 3. 200 ml of a 0.8 mol / L ammonium nitrate solution is heated to 85 °C, 10 g of Sample 3 is added, and it is stirred and exchanged for 2 h. The exchange is repeated 3 times, followed by centrifugation and washing, drying at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.0159 g of H2PtCl6·6H2O is added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, and it is impregnated for 12 h. The solution is placed in an oven at 120 °C for 12 h and calcined at 550 °C for 3 h, denoted as Sample 3 # , and the loading amount of the metal active component Pt is 0.1 wt%.

[0090] Preparation of the catalyst in Example 4

[0091] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of dodecyltrimethylammonium bromide (C 12 An aqueous solution with a concentration of 0.05 mol / L of TAB is heated in a water bath to 65 °C. 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 300) is added, and it is stirred at 65 °C for 30 min. Then, it is centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 4. 200 ml of a 0.8 mol / L ammonium nitrate solution is heated to 85 °C, 10 g of Sample 4 is added, and it is stirred and exchanged for 2 h. The exchange is repeated 3 times, followed by centrifugation and washing, drying at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.0159 g of H2PtCl6·6H2O is added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, and it is impregnated for 12 h., The solution is placed in an oven at 120 °C for 12 h and calcined at 550 °C for 3 h, denoted as Sample 4 # , and the loading amount of the metal active component Pt is 0.1 wt%.

[0092] Preparation of the catalyst in Example 5

[0093] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of octadecyltrimethylammonium bromide (C 18An aqueous solution with a concentration of 0.05 mol / L of TAB is heated in a water bath to 65 °C, 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 300) is added, stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 5. Take 200 ml of a 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 5, stir and exchange for 2 h, repeat the exchange 3 times, then perform centrifugal washing, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.0478 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, place the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 5 # , and the loading amount of the metal active component Pt is 0.3 wt%.

[0094] Preparation of the catalyst in Example 6

[0095] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16 An aqueous solution with a concentration of 0.05 mol / L of TAB is heated in a water bath to 65 °C, 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) is added, stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 6. Take 200 ml of a 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 6, stir and exchange for 2 h, repeat the exchange 3 times, then perform centrifugal washing, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.0478 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, place the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 6 # , and the loading amount of the metal active component Pt is 0.3 wt%.

[0096] Preparation of the catalyst in Example 7

[0097] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and cetyltrimethylammonium bromide (C 14An aqueous solution with a concentration of 0.05 mol / L of TAB was heated in a water bath to 65 °C, and 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio of 35) was added. It was stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid was neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 7. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 7 was added, and it was stirred and exchanged for 2 h. The exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.0478 g of H2PtCl6·6H2O was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 12 h, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 7 # , and the loading amount of the metal active component Pt was 0.3 wt%.

[0098] Preparation of the catalyst in Example 8

[0099] 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of dodecyltrimethylammonium bromide (C 12 An aqueous solution with a concentration of 0.05 mol / L of TAB was heated in a water bath to 65 °C, and 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio of 35) was added. It was stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid was neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 8. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 8 was added, and it was stirred and exchanged for 2 h. The exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.0478 g of H2PtCl6·6H2O was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 12 h, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 8 # , and the loading amount of the metal active component Pt was 0.3 wt%.

[0100] Preparation of the catalyst in Example 9

[0101] 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and octadecyltrimethylammonium bromide (C 18An aqueous solution with a concentration of 0.05 mol / L of TAB was heated in a water bath to 65 °C, 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio of 35) was added, stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid was neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 9. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 9 was added, stirred and exchanged for 2 h, the exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.0797 g of H2PtCl6·6H2O was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 12 h, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 9 # , and the loading amount of the metal active component Pt was 0.5 wt%.

[0102] Preparation of the catalyst in Example 10

[0103] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio of 35), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 10. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 10 was added, stirred and exchanged for 2 h, the exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.0797 g of H2PtCl6·6H2O was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 12 h,, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 10 # , and the loading amount of the metal active component Pt was 0.5 wt%.

[0104] For Sample 10 # the specific surface area and pore size distribution were tested, and the test results are shown in Figure 1 , it can be seen from the figure that Sample 10 # , its mesopore size distribution is about 5 nm, and its pore volume is 0.60 cm 3 / g; the specific surface area of the micropores is 213 m 2 / g, and the volume of the micropores is 0.09 cm3 / g; The specific surface area of the mesopores is 374 m 2 / g, and the volume of the mesopores is 0.51 cm 3 / g.

[0105] Preparation of the catalyst of Example 11

[0106] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 14 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio is 35), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 11; take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 11, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine it at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.0797 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine it at 550 °C for 3 h, denoted as Sample 11 # The loading amount of the metal active component Pt is 0.5 wt%.

[0107] Preparation of the catalyst of Example 12

[0108] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of dodecyltrimethylammonium bromide (C 12 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio is 35), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 12; take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 12, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine it at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.0797 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine it at 550 °C for 3 h, denoted as Sample 12 # The loading amount of the metal active component Pt is 0.5 wt%.

[0109] Preparation of Catalyst in Example 13

[0110] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 18 TAB). Heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio is 300), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 13. Take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 13, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine it at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.1115 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly. Impregnate for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 13 # The loading amount of the metal active component Pt is 0.7 wt%.

[0111] Preparation of Catalyst in Example 14

[0112] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16 TAB). Heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio is 35), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 14. Take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 14, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine it at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.1115 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly. Impregnate for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 14 # The loading amount of the metal active component Pt is 0.7 wt%.

[0113] Preparation of Catalyst in Example 15

[0114] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 14 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio of 150), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 15. Take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 15, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.1115 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly. Immerse for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 15 # , and the loading amount of the metal active component Pt is 0.7 wt%.

[0115] Preparation of the catalyst of Example 16

[0116] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of dodecyltrimethylammonium bromide (C 12 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (silica-alumina ratio of 35), stir at 65 °C for 30 min, then centrifuge and wash until the washing liquid is neutral. Dry the obtained molecular sieve solid at 120 °C for 12 h and calcine it at 550 °C for 5 h to obtain Sample 16. Take 200 ml of 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 16, stir and exchange for 2 h, repeat the exchange 3 times, then centrifuge and wash, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.1115 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly. Immerse for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 16 # , and the loading amount of the metal active component Pt is 0.7 wt%.

[0117] Preparation of the catalyst of Example 17

[0118] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of octadecyltrimethylammonium bromide (C 18An aqueous solution with a concentration of 0.05 mol / L of TAB is heated in a water bath to 65 °C. 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) is added, and it is stirred at 65 °C for 30 min. Then it is centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 17. Take 200 ml of a 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 17, stir and exchange for 2 h, repeat the exchange 3 times, then perform centrifugal washing, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.1593 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 17 # , and the loading amount of the metal active component Pt is 1 wt%.

[0119] Preparation of the catalyst in Example 18

[0120] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16 An aqueous solution with a concentration of 0.05 mol / L of TAB is heated in a water bath to 65 °C. 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) is added, and it is stirred at 65 °C for 30 min. Then it is centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 18. Take 200 ml of a 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 18, stir and exchange for 2 h, repeat the exchange 3 times, then perform centrifugal washing, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of a solution containing 0.1593 g of H2PtCl6·6H2O and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stir evenly, impregnate for 12 h, keep the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 18 # , and the loading amount of the metal active component Pt is 1 wt%.

[0121] Preparation of the catalyst in Example 19

[0122] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of tetradecyltrimethylammonium bromide (C 14An aqueous solution with a concentration of 0.05 mol / L of TAB was heated in a water bath to 65 °C, and 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) was added. It was stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid was neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 19. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 19 was added, and it was stirred and exchanged for 2 h. The exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.1593 g of H2PtCl6·6H2O was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 12 h, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 19 # , and the loading amount of the metal active component Pt was 1 wt%.

[0123] Preparation of the catalyst in Example 20

[0124] 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 12 An aqueous solution with a concentration of 0.05 mol / L of TAB was heated in a water bath to 65 °C, and 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) was added. It was stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid was neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 20. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 20 was added, and it was stirred and exchanged for 2 h. The exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of a solution containing 0.1593 g of H2PtCl6·6H2O was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 12 h, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 20 # , and the loading amount of the metal active component Pt was 1 wt%.

[0125] Preparation of the catalyst in Example 21

[0126] 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and cetyltrimethylammonium bromide (C 16An aqueous solution with a concentration of 0.05 mol / L of TAB was heated in a water bath to 65 °C, 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) was added, stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid was neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 21. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 21 was added, stirred and exchanged for 2 h, the exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of an AgNO3 solution containing 0.0694 g was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 24 h, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 21 # , the loading amount of the metal active component Ag is 1 wt%.

[0127] Preparation of the catalyst in Example 22

[0128] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16 An aqueous solution with a concentration of 0.05 mol / L of TAB was heated in a water bath to 65 °C, 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) was added, stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid was neutral. The obtained molecular sieve solid was dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 22. 200 ml of a 0.8 mol / L ammonium nitrate solution was heated to 85 °C, 10 g of Sample 22 was added, stirred and exchanged for 2 h, the exchange was repeated 3 times, then centrifuged and washed, dried at 120 °C for 12 h, and finally calcined at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. 4.2 ml of an AgNO3 solution containing 0.2082 g was added dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve and stirred evenly, impregnated for 24 h, the solution was placed in an oven at 120 °C for 12 h, and calcined at 550 °C for 3 h, denoted as Sample 22 # , the loading amount of the metal active component Ag is 3 wt%.

[0129] Preparation of the catalyst in Example 23

[0130] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16An aqueous solution with a concentration of 0.05 mol / L of TAB is heated in a water bath to 65 °C, 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35) is added, stirred at 65 °C for 30 min, then centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 23. Take 200 ml of a 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 23, stir and exchange for 2 h, repeat the exchange 3 times, then perform centrifugal washing, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of an AgNO3 solution containing 0.3469 g and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve, stir evenly, impregnate for 24 h, place the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 23 # , and the loading amount of the metal active component Ag is 5 wt%.

[0131] Preparation of the catalyst in Example 24

[0132] Take 600 ml of an aqueous solution containing 0.5 mol / L of NaOH and 0.05 mol / L of cetyltrimethylammonium bromide (C 16 TAB), heat it in a water bath to 65 °C, add 20 g of the parent ZSM-5 molecular sieve (with a silica-alumina ratio of 35), stir at 65 °C for 30 min, then centrifuged and washed until the washing liquid is neutral. The obtained molecular sieve solid is dried at 120 °C for 12 h and calcined at 550 °C for 5 h to obtain Sample 24. Take 200 ml of a 0.8 mol / L ammonium nitrate solution, heat it to 85 °C, add 10 g of Sample 24, stir and exchange for 2 h, repeat the exchange 3 times, then perform centrifugal washing, dry at 120 °C for 12 h, and finally calcine at 550 °C for 3 h to obtain the ZSM-5 type hierarchical pore molecular sieve. Take 4.2 ml of an AgNO3 solution containing 0.4857 g and add it dropwise to 6 g of the ZSM-5 type hierarchical pore molecular sieve, stir evenly, impregnate for 24 h, place the solution in an oven at 120 °C for 12 h, and calcine at 550 °C for 3 h, denoted as Sample 24 # , and the loading amount of the metal active component Ag is 7 wt%.

[0133] Application of the catalysts in Examples 25 - 48

[0134] Take 0.40 g of the sieved sample (Samples 1 # ~24 #) was loaded into a fixed-bed reactor. First, it was pretreated at 350 °C for 60 min in a He atmosphere (30 ml / min), then switched to H2 (100 ml / min) for reduction for 120 min, and then switched back to He (30 ml / min). After turning off H2, the temperature was lowered to 25 °C. Then the reduced sample was transferred into a water-bath steel reaction tube (inner diameter 5 mm). The flow rate of 100 ppm ethylene gas was adjusted to 25 ml / min to achieve a space velocity of 7500 h -1 . Analysis was carried out at 25 °C under a pressure of 0.2 MPa. The test results are shown in Table 1.

[0135] Application of the catalysts of Examples 49 - 72

[0136] Take 0.40 g of the sieved sample (sample 1, 40 - 60 mesh) # ~24 # ) was loaded into a fixed-bed reactor. First, it was pretreated at 350 °C for 60 min in a He atmosphere (30 ml / min), then switched to H2 (100 ml / min) for reduction for 120 min, and then switched back to He (30 ml / min). After turning off H2, the temperature was lowered to 25 °C. Then the reduced sample was transferred into a water-bath steel reaction tube (inner diameter 5 mm). The flow rate of 100 ppm ethylene gas was adjusted to 25 ml / min to achieve a space velocity of 7500 h -1 . Analysis was carried out at 0 °C under a pressure of 0.2 MPa. The test results are shown in Table 1.

[0137] Table 1 Activity evaluation results in the examples

[0138] Example Sample number Reaction temperature Stability Conversion rate % Example 26 <![CDATA[Sample 2 # > 25℃ 100h 80 Example 30 <![CDATA[Sample 6 # > 25℃ 770h 100 Example 34 <![CDATA[Sample 10 # > 25℃ 1200h 100 Example 38 <![CDATA[Sample 14 # > 25℃ 1000h 100 Example 45 <![CDATA[Sample 21 # > 25℃ 300h 100 Example 46 <![CDATA[Sample 22 # > 25℃ 550h 100 Example 47 <![CDATA[Sample 23 # > 25℃ 1050h 100 Example 50 <![CDATA[Sample 2 # > 0℃ 35h 50 Example 54 <![CDATA[Sample 6 # > 0℃ 320h 100 Example 58 <![CDATA[Sample 10 # > 0℃ 700h 100 Example 62 <![CDATA[Sample 14 # > 0℃ 500h 100

[0139] It can be seen from Table 1 that in the specific preparation methods described, Example 33 showed good activity and stability at 25 °C, and Example 57 showed good activity and stability at 0 °C.

[0140] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent embodiments and all fall within the scope of the technical solution.

Claims

1. A method for removing ethylene at low temperature, characterized in that, Contact a raw material containing ethylene with a pre-reduced ZSM-5 type catalyst to carry out the ethylene oxidation reaction; The temperature of the ethylene oxidation reaction is -25°C to 35°C; The ZSM-5 type catalyst includes a carrier and an active component; The carrier is a ZSM-5 type hierarchical pore molecular sieve; The active component includes an active element selected from at least one of Pt, Pd, Ag, Au, Ru, Rh, Os, and Ir; The ZSM-5 type hierarchical pore molecular sieve has micropores and mesopores.

2. The method according to claim 1, characterized in that, In the ZSM-5 type catalyst, the mass percentage of the active component in the carrier is 0.01 wt% to 10 wt%, where the mass of the active component is calculated based on the mass of the active element; The specific surface area of the micropores is 100 to 300 m 2 / g, and the volume of the micropores is 0.05 to 0.15 cm 3 / g; The specific surface area of the mesopores is 200 to 550 m 2 / g, the volume of the mesopores is 0.3 to 0.8 cm 3 / g, and the pore diameter of the mesopores is 2 to 8 nm.

3. The method according to claim 1, characterized in that, The preparation method of the ZSM-5 type catalyst includes: (1) Treat ZSM-5 molecular sieve in an alkaline solution containing a surfactant, stir I, dry I, and calcine I to obtain the alkali-treated molecular sieve; (2) Perform ammonium exchange on the alkali-treated molecular sieve obtained in (1), dry II, and calcine II to obtain the ZSM-5 type hierarchical pore molecular sieve; (3) Impregnate the ZSM-5 type hierarchical pore molecular sieve described in step (2) with an equal volume of an aqueous solution containing a precursor of the active component, dry III, and calcine III to obtain the ZSM-5 type catalyst.

4. The method according to claim 3, characterized in that, In step (1), the silica-alumina ratio of the ZSM-5 molecular sieve is 20 to 1000.

5. The method according to claim 3, characterized in that, The alkaline substance in the alkaline solution is selected from at least one of sodium hydroxide, potassium hydroxide, and sodium carbonate; In the alkaline solution, the concentration of the alkaline substance is 0.1 to 3 mol / L; Preferably, the surfactant is selected from at least one of decyltrimethylammonium bromide, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, and octadecyltrimethylammonium bromide; In the alkaline solution, the concentration of the surfactant is 0.05 to 0.2 mol / L.

6. The method according to claim 3, characterized in that, The solid-liquid ratio of the ZSM-5 molecular sieve to the alkaline solution is 1:10 to 50 g / ml.

7. The method according to claim 3, characterized in that, In step (1), the temperature of the stirring I is 30 to 90°C, and the time of the stirring I is 10 to 60 min; The drying I temperature is 60 to 120°C, and the drying I time is 10 to 24 hours; The calcination I temperature is 500 to 700°C, and the calcination I time is 2 to 8 h; In step (2), the drying II temperature is 100 to 120°C, and the drying II time is 10 to 24 hours; The calcination II temperature is 400 to 600°C, and the calcination II time is 2 to 5 hours.

8. The method according to claim 3, characterized in that, In step (3), the precursor of the active component is selected from at least one of H2PtCl6·6H2O, PdCl, AgNO, RuCl, RhCl, OsCl, and IrCl; Preferably, the impregnation time is 12 to 24 h; The drying III temperature is 60 to 120°C, and the drying III time is 10 to 24 hours; The calcination III temperature is 500 to 1000°C, and the calcination III time is 2 to 8 h.

9. The method according to claim 1, wherein The conditions for the pre-reduction include: The atmosphere for the pre-reduction is H2; The time of pre-reduction is 1 to 3 h, and the temperature of pre-reduction is 200 to 600 °C.

10. The method according to claim 1, wherein In the raw material, the concentration of ethylene is 0.1 ppm to 1000 ppm; The space velocity of the raw material is 5000-10000 h -1 ; The pressure of the reaction is 0.1 to 0.5 MPa.

Images