Mesoporous ssz-39 molecular sieves and methods of making the same x Reaction catalyst

Abstract

The application provides a mesoporous SSZ-39 molecular sieve and a preparation method thereof and a DeNO x x catalyst. The preparation method comprises the following steps: mixing a silicon source, an aluminum source, an alkali source, an organic template agent, a cage polysiloxane and water, aging to obtain a gel; and stirring, crystallizing and calcining the gel to obtain the mesoporous SSZ-39 molecular sieve. x x catalyst. The application realizes the introduction of mesopores without reducing the relative crystallinity of the SSZ-39 molecular sieve by adding the cage polysiloxane in raw materials, and the mesoporous SSZ-39 molecular sieve has a larger mesopore volume and better DeNO x x activity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of molecular sieve synthesis, and particularly relates to a mesoporous SSZ-39 molecular sieve, a preparation method thereof and a flue gas DeNO x x catalyst. BACKGROUND

[0002] The SSZ-39 molecular sieve is a molecular sieve with AEI topology structure, which is formed by AlO4 and SiO4 tetrahedrons through oxygen atoms in a head-to-tail manner to form a double six-membered ring secondary building unit (SBU), and the double six-membered rings of adjacent two layers are arranged in a cross distribution by rotating 180 degrees around the z axis, and the double six-membered rings are connected and arranged through four-membered rings to form a aei cage (asymmetrical pear-shaped cage) with an eight-membered ring structure and a three-dimensional pore structure, and the pore size is Due to the ordered pore structure, high specific surface area, good hydrothermal stability, more surface proton acid center and excellent cation exchangeability of the SSZ-39 molecular sieve, in recent years, the SSZ-39 molecular sieve has shown excellent performance in industrial catalytic processes such as NH3-selective catalytic reduction (NH3-SCR) and methanol-to-olefin catalytic reaction (MTO).

[0003] In 1999, Zones et al. (S.I.Zones, Y.Nakagawa, S.T.Evans, G.S.Lee, Zeolite SSZ-39, US Patent: 5958370, 1999) synthesized the SSZ-39 molecular sieve for the first time by using different organic templates as templates. However, because the pore size is small, the reactants are limited, and therefore, how to improve the diffusion performance of the molecular sieve itself becomes the top priority. At present, the conventional way of introducing mesopores is often introduced on the basis of destroying the micropore structure of the molecular sieve, but this leads to the destruction of the framework and the decrease of stability, and it is difficult to maintain a high relative crystallinity.

[0004] Therefore, under the premise of not destroying the framework structure of the SSZ-39 molecular sieve and not reducing the relative crystallinity, introducing the mesopore structure as a high-efficiency DeNO x x catalyst becomes a problem to be solved at present. SUMMARY

[0005] To solve the above technical problems, the purpose of the present application is to provide a mesoporous SSZ-39 molecular sieve, a preparation method thereof and a DeNO x x catalyst. By adding a cage-like silsesquioxane substance in the raw material, the SSZ-39 molecular sieve provided by the present application can have a large mesopore volume while maintaining the relative crystallinity, and can be applied to DeNO x x reaction.

[0006] To achieve the above object, the present application provides a preparation method of mesoporous SSZ-39 molecular sieve, wherein the preparation method comprises: taking a silicon source, an aluminum source, an alkali source, an organic template agent and water as first raw materials, taking a cage polysilsesquioxane substance as second raw materials, mixing the first raw materials and the second raw materials, aging to obtain a gel; stirring, crystallizing and calcining the gel to obtain the mesoporous SSZ-39 molecular sieve.

[0007] According to a specific embodiment of the present application, preferably, the cage polysilsesquioxane substance is a POSS chemical, including one or more than two combinations of aminopropyl isobutyl polyhedral oligomeric silsesquioxane, aminopropyl heptyl-cage polysilsesquioxane, an acrylic-cage polysilsesquioxane, trans-cyclohexanediol isobutyl cage polysilsesquioxane, octaphenyl cage polysilsesquioxane, octavinyl octasilsesquioxane.

[0008] According to a specific embodiment of the present application, preferably, the silicon source includes one or more than two combinations of silicon dioxide, silica sol, silicate, orthosilicate, solid water glass, liquid water glass, silicon powder, and more preferably is silica sol.

[0009] According to a specific embodiment of the present application, preferably, the aluminum source includes one or more than two combinations of USY molecular sieve, ZSM-5 molecular sieve, Beta molecular sieve, sodium metaaluminate, aluminum hydroxide, pseudo-boehmite, aluminum isopropyl alcohol, aluminum sol, boehmite, kaolin, bentonite, and more preferably is USY molecular sieve.

[0010] According to a specific embodiment of the present application, preferably, the alkali source includes one or a combination of sodium hydroxide and potassium hydroxide, and more preferably is sodium hydroxide.

[0011] According to a specific embodiment of the present application, preferably, the organic template comprises one or a combination of two or more of the following: N,N-diethyl-2,6-dimethylpiperidinium ion, 3,5-dimethyl-N,N-dimethylpiperidinium ion, N,N-diethyl-2-ethylpiperidinium ion, N-ethyl-N-propyl-2,6-dimethylpiperidinium ion, N-methyl-N-ethyl-2,6-dimethylpiperidinium ion, N-methyl-N-ethyl-2-ethylpiperidinium ion, 2,5-dimethyl-N,N-diethylpyrrolidinium ion, 2,6-dimethyl-N,N-dimethylpiperidinium ion, 2-ethyl-N,N-dimethylpiperidinium ion, 2,2,6,6-tetramethyl-N-methyl-N-ethylpiperidinium ion, 2,2,6,6-tetramethyl-N,N-dimethylpiperidinium ion, N,N-dimethyl-N,N-bicyclononane ion. More preferably, the organic template comprises one or a combination of two or more of the following: N,N-diethyl-2,6-dimethylpiperidinium ion compound, 3,5-dimethyl-N,N-dimethylpiperidinium ion compound, N,N-dimethyl-N,N-bicyclononane ion compound.

[0012] In the above preparation method, preferably, the chemical composition of the first raw material satisfies the following molar ratio ranges: SiO2 / Al2O3 = 5-180, OH - / SiO2 = 1 or less, H2O / SiO2 = 3-80, R / SiO2 = 0.5 or less; wherein R is the number of moles of the organic template, the silicon source is calculated as silicon dioxide, the aluminum source is calculated as aluminum trioxide, and the base is calculated as hydroxide ion. Specifically, SiO2 / Al2O3 can be 5, 10, 20, 30, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, and the like, as well as ranges having any two of the above specific values as endpoints; OH - / SiO2 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, and the like, as well as ranges having any two of the above specific values as endpoints; H2O / SiO2 can be 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, and the like, as well as ranges having any two of the above specific values as endpoints; R / SiO2 can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, and the like, as well as ranges having any two of the above specific values as endpoints.

[0013] In the above preparation method, preferably, A / B = 0.01%-3%, wherein A is the mass of the cage silsesquioxane substance, and B is the total mass of the first raw material, based on 100% of the total mass of the first raw material.

[0014] In some embodiments, more preferably, the chemical composition of the first raw material satisfies the following molar ratio ranges: SiO2 / Al2O3 = 5-100, OH - / SiO2 = 0.7 or less, H2O / SiO2 = 5-40, R / SiO2 = 0.05-0.4.

[0015] In some embodiments, more preferably, A / B = 0.03%-1.5% based on the total mass of the first raw material being 100%.

[0016] The cage-structured silsesquioxane species has a large volume, which can effectively increase the construction efficiency of mesopores, so that a large mesopore volume can be produced at a lower addition amount.

[0017] In the above preparation method, preferably, the aging temperature is room temperature to 100°C, and the aging time is 0.1-100h; further, the aging time is more preferably 1-5h.

[0018] In the above preparation method, preferably, the stirring temperature is room temperature, and the stirring time is 5h or less; further, the stirring time is more preferably 0.5-1h.

[0019] In some embodiments, the stirring can be in the form of rotation.

[0020] In the above preparation method, preferably, the crystallization temperature is 120-210°C. Specifically, the crystallization temperature can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, and the like specific values and ranges with any two of the above specific values as end points.

[0021] In the above preparation method, preferably, the crystallization time is 38-120h; further, the crystallization time is more preferably 50-100h.

[0022] In the above preparation method, preferably, the calcination temperature is 400-700°C, and the calcination time is 2-6h; further, the calcination temperature is more preferably 450-600°C, and the calcination time is more preferably 3-5h.

[0023] According to the specific embodiments of the present application, preferably, the above preparation method further comprises sequentially performing the operations of cooling, filtering, washing, and drying after crystallization and before calcination.

[0024] According to the specific embodiments of the present application, preferably, the above preparation method specifically comprises the following steps:

[0025] 1. A first raw material comprising a silicon source, an aluminum source, an alkali source, an organic template agent, and water, and a second raw material comprising a cage silsesquioxane substance, wherein the first raw material and the second raw material are mixed and stirred uniformly in a certain ratio and order, and are aged at room temperature to 100 DEG C for 0.1-100 hours to obtain a gel;

[0026] The first raw material has a chemical composition satisfying the following molar ratio ranges: SiO2 / Al2O3 = 5-180, OH - / SiO2 = 1 or less, H2O / SiO2 = 3-80, and R / SiO2 = 0.5 or less, wherein R is the number of moles of the organic template agent;

[0027] In terms of the total mass of the first raw material, A / B = 0.01%-3%, wherein A is the mass of the cage silsesquioxane substance, and B is the total mass of the first raw material.

[0028] 2. The gel is placed in an autoclave and stirred at room temperature for 5 hours or less, is kept in the stirred state, and is crystallized at 120-210 DEG C for 38-120 hours, and then is cooled to 40 DEG C or less, filtered, washed, dried, and calcined at 400-700 DEG C for 2-6 hours to obtain the SSZ-39 molecular sieve.

[0029] The application further provides a mesoporous SSZ-39 molecular sieve obtained by the above preparation method.

[0030] According to a specific embodiment of the application, compared with a conventional SSZ-39 molecular sieve, the SSZ-39 molecular sieve provided by the application can introduce mesopores without reducing the relative crystallinity, has a larger mesopore volume, and thus improves the catalytic activity for DeNO x reaction.

[0031] According to a specific embodiment of the application, preferably, the mesopore volume of the mesoporous SSZ-39 molecular sieve is 0.05-0.13 cm 3 / g, and more preferably 0.08-0.13 cm 3 / g.

[0032] According to a specific embodiment of the application, preferably, the relative crystallinity of the mesoporous SSZ-39 molecular sieve is 85% or more, and more preferably 90% or more.

[0033] According to a specific embodiment of the application, preferably, the specific surface area of the mesoporous SSZ-39 molecular sieve is 680-730 m 2 / g, and more preferably 715-730 m 2 / g.

[0034] According to a specific embodiment of the present application, preferably, the micropore volume of the SSZ-39 molecular sieve with mesopores is 0.25-0.29 cm 3 / g, more preferably 0.27-0.29 cm 3 / g.

[0035] The present application also provides a DeNO x x reaction catalyst. x The DeNO x x reaction catalyst comprises the above-mentioned SSZ-39 molecular sieve, or the raw material of the DeNO x x reaction catalyst comprises the above-mentioned SSZ-39 molecular sieve. The SSZ-39 molecular sieve provided by the present application has a larger mesopore volume and retains a higher relative crystallinity, thereby showing a higher DeNO x x reaction catalytic activity: the conversion rate in the DeNO x x reaction at 350℃ can reach more than 95%, and the conversion rate in the DeNO x x reaction at 550℃ can reach more than 93%.

[0036] The present application also provides a DeNO x x reaction method, which is realized by using the above-mentioned SSZ-39 molecular sieve with mesopores or the above-mentioned DeNO x x reaction catalyst. The DeNO x x reaction method provided by the present application has a volume space velocity of 80000-150000 h -1 , preferably 120000 h -1 ; and a reaction temperature of 150℃-650℃, preferably 200-600℃.

[0037] The present application has the beneficial effect that, compared with the prior art, the present application realizes the introduction of mesopores on the basis of not reducing the relative crystallinity by introducing cage silsesquioxane substances in the process of synthesizing pure-phase SSZ-39 molecular sieve, and a larger mesopore volume is obtained, thereby improving the diffusion performance of the molecular sieve, making it have better catalytic activity, and being applicable to the field of DeNO x x reaction catalysis. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 XRD patterns of SSZ-39 molecular sieves of Examples 1-5 and Comparative Example 1. DETAILED DESCRIPTION

[0039] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but cannot be understood as limiting the implementable scope of the present application.

[0040] Example 1

[0041] The present example provides a SSZ-39 molecular sieve, and a preparation method thereof comprises:

[0042] 1. Sodium hydroxide, pure water, silica sol with a concentration of 40 wt%, 3,5-dimethyl-N,N-dimethylhydroxypiperidine aqueous solution (as an organic template agent) with a concentration of 25 wt%, aminopropyl isobutyl polyhedral oligomeric silsesquioxane and USY molecular sieve are fully mixed to obtain a raw material composition with the following molar ratio composition:

[0043] SiO2 / Al2O3 = 55,

[0044] Organic template agent (abbreviation: SDA) / SiO2 = 0.2,

[0045] Aminopropyl isobutyl polyhedral oligomeric silsesquioxane / first raw material = 0.5%,

[0046] OH - / SiO2 = 0.6,

[0047] H2O / SiO2 = 30.

[0048] 2. Aging at room temperature for 1 h to obtain a synthesis gel.

[0049] 3. The synthesis gel is loaded into an autoclave and stirred at room temperature for 0.5 h.

[0050] 4. The temperature is raised to 160°C and crystallized for 50 h.

[0051] 5. The crystallization is stopped, the temperature is lowered to below 40°C, filtered, washed, the solid sample is dried, and calcined at 550°C for 4 h to obtain a SSZ-39 molecular sieve.

[0052] The XRD pattern of the SSZ-39 molecular sieve sample of the present example is shown in Figure 1 The relative crystallinity of the sample is calculated to be 95%, the specific surface area is 725 m 2 / g, the micropore volume is 0.28 cm 3 / g, and the mesopore volume is 0.10 cm 3 / g.

[0053] Example 2:

[0054] The present example provides a SSZ-39 molecular sieve, and a preparation method thereof comprises:

[0055] 1. Mix sodium hydroxide, pure water, silica sol with a silica concentration of 40 wt%, 3,5-dimethyl-N,N-dimethylhydroxypiperidine aqueous solution (as an organic template agent) with a concentration of 25 wt%, trans-cyclohexanediol isobutylated cage silsesquioxane, and USY molecular sieve to obtain a raw material composition with the following molar ratio composition:

[0056] SiO2 / Al2O3 = 70,

[0057] Organic template agent (abbreviation: SDA) / SiO2 = 0.2,

[0058] Trans-cyclohexanediol isobutylated cage silsesquioxane / first raw material = 0.05%,

[0059] OH - / SiO2 = 0.6,

[0060] H2O / SiO2 = 30.

[0061] 2. Age at room temperature for 1 h to obtain a synthesis gel.

[0062] 3. Load the synthesis gel into an autoclave and stir at room temperature for 0.5 h.

[0063] 4. Heat to 180°C and crystallize for 60 h.

[0064] 5. Stop the crystallization, cool to below 40°C, filter, wash, dry the solid sample, and calcine at 550°C for 4 h to obtain SSZ-39 molecular sieve.

[0065] The XRD pattern of the SSZ-39 molecular sieve sample of this example is shown in Figure 1 Fig. 1. The relative crystallinity of this sample was calculated to be 91%, the specific surface area was 720 m 2 / g, the micropore volume was 0.27 cm 3 / g, and the mesopore volume was 0.11 cm 3 / g.

[0066] Example 3:

[0067] This example provides a SSZ-39 molecular sieve, and a preparation method thereof, which comprises:

[0068] 1. Mix sodium hydroxide, pure water, silica sol with a silica concentration of 40 wt%, 3,5-dimethyl-N,N-dimethylhydroxypiperidine aqueous solution (as an organic template agent) with a concentration of 25 wt%, trans-cyclohexanediol isobutylated cage silsesquioxane, and USY molecular sieve to obtain a raw material composition with the following molar ratio composition:

[0069] SiO2 / Al2O3 = 45,

[0070] Organotemplate (SDA) / SiO2= 0.2,

[0071] Octaphenylsilsesquioxane / first raw material = 1%,

[0072] OH - / SiO2= 0.5,

[0073] H2O / SiO2= 20.

[0074] 2. Age at room temperature for 1 h to obtain a synthesis gel.

[0075] 3. Load the synthesis gel into an autoclave and stir at room temperature for 0.5 h.

[0076] 4. Increase the temperature to 170°C and crystallize for 40 h.

[0077] 5. Stop the crystallization, decrease the temperature to below 40°C, filter, wash, dry the solid sample, and calcine at 550°C for 4 h to obtain the SSZ-39 molecular sieve.

[0078] The XRD pattern of the SSZ-39 molecular sieve sample of this example is shown in Figure 1 Fig. 1. The relative crystallinity of this sample was calculated to be 95%, the specific surface area was 715 m 2 / g, the micropore volume was 0.27 cm 3 / g, and the mesopore volume was 0.13 cm 3 / g.

[0079] Example 4:

[0080] This example provides a SSZ-39 molecular sieve, the preparation method of which comprises:

[0081] 1. Mix sodium hydroxide, pure water, silica sol with a concentration of 40 wt%, 3,5-dimethyl-N,N-dimethylhydroxypiperidine aqueous solution (as an organic template) with a concentration of 25 wt%, aminopropylheptyl-cage polysilsesquioxane, and ZSM-5 molecular sieve to obtain a raw material composition having the following molar ratio composition:

[0082] SiO2 / Al2O3= 45,

[0083] Organotemplate (SDA) / SiO2= 0.2,

[0084] Aminopropylheptyl-cage polysilsesquioxane / first raw material = 0.7%,

[0085] OH - / SiO2= 0.5,

[0086] H2O / SiO2 = 20.

[0087] 2. Age the synthesis gel at room temperature for 1 h.

[0088] 3. Load the synthesis gel into an autoclave and stir at room temperature for 0.5 h.

[0089] 4. Increase the temperature to 170 °C and crystallize for 40 h.

[0090] 5. Stop the crystallization, decrease the temperature to below 40 °C, filter, wash, oven dry the solid sample, and calcine at 550 °C for 4 h to obtain the SSZ-39 molecular sieve.

[0091] The XRD pattern of the SSZ-39 molecular sieve sample of this example is shown in Figure 1 Fig. 2. The relative crystallinity of this sample was calculated to be 93%, the specific surface area was 730 m 2 / g, the micropore volume was 0.29 cm 3 / g, and the mesopore volume was 0.11 cm 3 / g.

[0092] Example 5:

[0093] This example provides a SSZ-39 molecular sieve, the method for preparing which comprises:

[0094] 1. Mix sodium hydroxide, purified water, a silica sol having a concentration of 40 wt%, an aqueous 3,5-dimethyl-N,N-dimethylhydroxypiperidine solution (as an organic template agent) having a concentration of 25 wt%, octavinyl octasilsesquioxane, and BETA molecular sieve to obtain a raw material composition having the following molar ratio composition:

[0095] SiO2 / Al2O3 = 45,

[0096] organic template agent (abbreviated as SDA) / SiO2 = 0.2,

[0097] octavinyl octasilsesquioxane / first raw material = 0.3%,

[0098] OH - / SiO2 = 0.5,

[0099] H2O / SiO2 = 20.

[0100] 2. Age the synthesis gel at room temperature for 1 h.

[0101] 3. Load the synthesis gel into an autoclave and stir at room temperature for 5 h.

[0102] 4. Increase the temperature to 180 °C and crystallize for 50 h.

[0103] 5. Stop the crystallization, cool down to below 40°C, filter, wash, dry the solid sample, and calcine at 550°C for 4h to obtain the SSZ-39 molecular sieve.

[0104] The XRD pattern of the SSZ-39 molecular sieve sample of this example is shown in Figure 1 Fig. 2. The relative crystallinity of this sample was calculated to be 92%, the specific surface area was 715 m 2 / g, the micropore volume was 0.27 cm 3 / g, and the mesopore volume was 0.08 cm 3 / g.

[0105] Comparative Example 1

[0106] This comparative example provides a SSZ-39 molecular sieve, the method for preparing which comprises:

[0107] 1. Mix sodium hydroxide, pure water, a silica sol having a silica concentration of 40 wt%, a 3,5-dimethyl-N,N-dimethylhydroxypiperidine aqueous solution (as an organic template agent) having a concentration of 25 wt%, and a USY molecular sieve to obtain a raw material composition having the following molar ratio composition:

[0108] Si02 / Al203= 45,

[0109] organic template agent (abbreviated as SDA) / Si02= 0.2,

[0110] OH - / Si02= 0.5,

[0111] H20 / Si02= 20.

[0112] 2. Age for 1h at room temperature to obtain a synthesis gel.

[0113] 3. Load the synthesis gel into an autoclave and stir for 0.5h at room temperature.

[0114] 4. Increase the temperature to 160°C and crystallize for 50h.

[0115] 5. Stop the crystallization, cool down to below 40°C, filter, wash, dry the solid sample, and calcine at 550°C for 4h to obtain the SSZ-39 molecular sieve.

[0116] The XRD pattern of the SSZ-39 molecular sieve sample of this comparative example is shown in Figure 1 Fig. 2. The relative crystallinity of this sample was calculated to be 92%, the specific surface area was 715 m 2 / g, the micropore volume was 0.27 cm 3 / g, and the mesopore volume was 0.08 cm 3 / g.

[0117] Test Example 1

[0118] The present test example provides NH3-SCR reaction performance tests for SSZ-39 molecular sieve samples prepared in Examples 1-5 and Comparative Example 1, and the specific test method comprises:

[0119] (1) Ammonium exchange of molecular sieve: The SSZ-39 molecular sieves prepared in Examples 1-5 and Comparative Example 1 were used as test samples, and were mixed with ammonium nitrate and water according to a mass ratio of ammonium nitrate:molecular sieve:water = 1:1:10. After adjusting the pH to 8-8.5 with ammonia water, the mixture was exchanged at 90°C for 1h under stirring, and then was filtered, washed, dried, and calcined at 550°C for 4h. The above process was repeated 3 times until the Na2O content in the molecular sieve was less than 0.1%.

[0120] (2) Copper loading of molecular sieve: Copper acetate was dissolved in 50 times water to obtain a solution with a CuO loading of 5% on the molecular sieve. The ammonium-exchanged molecular sieve was added to the solution under stirring, and then was filtered, washed, dried, and calcined at 550°C for 4h after adjusting the pH to 8-8.5 with ammonia water.

[0121] (3) The Cu-SSZ-39 composite molecular sieves prepared in Examples 1-5 and Comparative Example 1 were tabletted, crushed, sieved, and hydrothermally aged at 650°C for 100h under a 10% H2O+90% nitrogen atmosphere. Then, 0.5g of the sample with a particle size of 40-60 mesh was used for NH3-SCR reaction, wherein the composition of the reaction mixed gas was: 1000ppm NO, 1100ppm NH3, 10Vol% O2, 10Vol% H2O, N2 as the balance gas, the volume space velocity was 120000h-1, the reaction temperature was 200-600°C, and the NO concentration in the tail gas was detected online using a MKS infrared gas analyzer. The test results are shown in Table 1. -1 x

[0122] (4) The conversion rate of NO x was defined as:

[0123]

[0124] wherein, [NO] in was the NO concentration in the reaction mixed gas, [NO] out was the NO concentration in the tail gas, [NO2] out was the NO2 concentration in the tail gas, and [N2O] out was the N2O concentration in the tail gas.

[0125] Table 1. Conversion rate of nitrogen oxides in the reaction mixed gas at different temperatures (150-350°C)

[0126] Table 1. Conversion rate of nitrogen oxides in the reaction mixed gas at different temperatures (150-350°C)​ 150℃ 350℃ 550℃ Example 1 61 96 93 Example 2 62 97 95 Example 3 60 95 96 Example 4 63 96 94 Example 5 61 99 95 Comparative Example 1 Comparative Example 2 58 95 93

[0127] From the data in Table 1, it can be seen that, compared with the raw material without adding the cage-like silsesquioxane substance, the nitrogen oxide conversion rate of the mesoporous Cu-SSZ-39 molecular sieve prepared by the cage-like silsesquioxane substance in the embodiment of the present application is overall better than that of the molecular sieve obtained without adding the cage-like silsesquioxane substance in the temperature range of 150-550℃. This shows that adding the cage-like silsesquioxane substance in the raw material can effectively improve the DeNO x activity of the SSZ-39 molecular sieve.

[0128] The above results show that the cage-like silsesquioxane substance can be used as an additive to prepare the SSZ-39 molecular sieve with high relative crystallinity and large mesopore volume, and the microporous structure is not damaged, thereby improving the diffusion performance of the SSZ-39 molecular sieve and increasing the DeNO x reaction activity. The preparation method of the SSZ-39 molecular sieve is simple, the production cost is low, and has a good popularization prospect.

Claims

1. A method for making a mesoporous SSZ-39 molecular sieve, wherein, The preparation method includes: Using silicon source, aluminum source, alkali source, organic template agent and water as the first raw material, and cage-like silsesquioxane substance as the second raw material, the first raw material and the second raw material are mixed and aged to obtain a gel; The gel was stirred, crystallized, and calcined to obtain the mesoporous SSZ-39 molecular sieve. wherein the chemical composition of the first raw material satisfies the following molar ratio ranges: SiO2 / Al2O3 = 5-180, OH - / SiO2 = 1 or less, H2O / SiO2 = 3-80, R / SiO2 = 0.5 or less, where R is the number of moles of the organic template; With the total mass of the first raw material as 100%, A / B = 0.01%-3%, where A is the mass of the cage-like silsesquioxane substance and B is the total mass of the first raw material; The cage-like silsesquioxanes include one or more of the following: aminopropyl isobutyl polyhedral oligomeric silsesquioxanes, aminopropyl heptyl-cage-like polysilsesquioxanes, acrylic-cage-like polysilsesquioxanes, trans-cyclohexanediol isobutylated cage-like silsesquioxanes, octaphenyl cage-like silsesquioxanes, and octavinyloctasilsesquioxanes.

2. The production method according to claim 1, wherein The silicon source includes one or more of silicon dioxide, silicates, and orthosilicates.

3. The method of making according to claim 2, wherein, The silicate includes solid water glass and / or liquid water glass.

4. The production method according to claim 1, wherein The silicon source is silica sol and / or silicon powder.

5. The production method according to claim 1, wherein The aluminum source includes one or more of the following: USY molecular sieve, ZSM-5 molecular sieve, Beta molecular sieve, sodium aluminate, aluminum hydroxide, boehmite, aluminum isopropoxide, aluminum sol, boehmite, kaolin, and bentonite.

6. The production method according to claim 5, wherein The aluminum source is USY molecular sieve.

7. The production method according to claim 1, wherein The organic template agent comprises one or more combinations of compounds capable of providing one of the following ions: N,N-diethyl-2,6-dimethylpiperidine ion, 3,5-dimethyl-N,N-dimethylpiperidine ion, N,N-diethyl-2-ethylpiperidine ion, N-ethyl-N-propyl-2,6-dimethylpiperidine ion, N-methyl-N-ethyl-2,6-dimethylpiperidine ion, N-methyl-N-ethyl-2-ethylpiperidine ion, 2,5-dimethyl-N,N-diethylpyrrole ion, 2,6-dimethyl-N,N-dimethylpiperidine ion, 2-ethyl-N,N-dimethylpiperidine ion, 2,2,6,6-tetramethyl-N-methyl-N-ethylpiperidine ion, 2,2,6,6-tetramethyl-N,N-dimethylpiperidine ion, and N,N-dimethyl-N,N-bicyclononane ion.

8. The production method according to claim 7, wherein The organic template agent includes one or more of the following: N,N-diethyl-2,6-dimethylpiperidine ionic compound, 3,5-dimethyl-N,N-dimethylpiperidine ionic compound, and N,N-dimethyl-N,N-bicyclononane ionic compound.

9. The method of making according to any one of claims 1-8, wherein, The chemical composition of the first raw material satisfies the following molar ratio ranges: Si02 / Al203 = 5-100, OH - / Si02 = 0.7 or less, H20 / Si02 = 5-40, R / Si02 = 0.05-0.

4.

10. The method of making according to any one of claims 1-8, wherein, Based on the total mass of the first raw material being 100%, A / B = 0.03%-1.5%.

11. The method of making according to claim 1, wherein, The aging temperature is from room temperature to 100°C, and the aging time is 0.1-100 h.

12. The production method according to claim 11, wherein The aging time is 1-5 hours.

13. The method of producing according to claim 1, wherein, The stirring temperature is room temperature, and the stirring time is less than 5 hours.

14. The production method according to claim 13, wherein The stirring time is 0.5-1 hour.

15. The method of producing according to claim 1, wherein, The crystallization temperature is 120-210℃, and the crystallization time is 38-120h.

16. The method of manufacturing according to claim 15, wherein, The crystallization time is 50-100 hours.

17. A mesoporous SSZ-39 molecular sieve obtained by the preparation method of any one of claims 1-16.

18. The mesoporous SSZ-39 molecular sieve of claim 17, wherein, The mesoporous SSZ-39 molecular sieve has a mesopore volume of 0.05 to 0.13 cm3 / g. 3 / g.

19. The mesoporous SSZ-39 molecular sieve of claim 18, wherein, The mesoporous SSZ-39 molecular sieve has a mesopore volume of 0.08 to 0.13 cm 3 / g.

20. The mesoporous SSZ-39 molecular sieve of claim 17, wherein, The relative crystallinity of the mesoporous SSZ-39 molecular sieve is 85% or more.

21. The mesoporous SSZ-39 molecular sieve of claim 20, wherein, The relative crystallinity of the mesoporous SSZ-39 molecular sieve is 90% or more.

22. The mesoporous SSZ-39 molecular sieve of claim 17, wherein, The mesoporous-containing SSZ-39 molecular sieve has a specific surface area of 680-730 m 2 / g.

23. The mesoporous SSZ-39 molecular sieve of claim 22, wherein, The mesoporous-containing SSZ-39 molecular sieve has a specific surface area of 715-730 m 2 / g.

24. The mesoporous SSZ-39 molecular sieve of claim 17, wherein, The mesoporous SSZ-39 molecular sieve has a micropore volume of 0.25 to 0.29 cm3 / g. 3 / g.

25. The mesoporous SSZ-39 molecular sieve of claim 24, wherein, The mesoporous SSZ-39 molecular sieve has a micropore volume of 0.27-0.29 cm 3 / g.

26. A flue gas denitration reaction catalyst comprising the mesoporous SSZ-39 molecular sieve of any one of claims 17-25, or a raw material of the flue gas denitration reaction catalyst comprising the mesoporous SSZ-39 molecular sieve of any one of claims 17-25.

27. A flue gas denitration method using the mesoporous SSZ-39 molecular sieve of any one of claims 17-25 or the flue gas denitration reaction catalyst of claim 26.

28. The flue gas deNOx method according to claim 27, wherein The flue gas denitration method has a volume space velocity of 80000-150000 h -1 .

29. The flue gas deNOx method according to claim 28, wherein, The flue gas denitration method has a volume space velocity of 120000 h -1 .

30. The flue gas deNOx method according to claim 27, wherein The reaction temperature of the flue gas denitration method is 150-650 ℃.

31. The flue gas de-NOx method according to claim 30, wherein The reaction temperature of the flue gas denitration method is 200-600 ℃.

Images