SSZ-39 molecular sieve, method for preparing the same, and de nox reaction catalyst

Abstract

The application provides a SSZ-39 molecular sieve, a preparation method thereof and a DeNOx reaction catalyst. The preparation method comprises the following steps: mixing a silicon source, an aluminum source, an alkali source, an organic template agent, an oxygen-containing substance and water, aging, and obtaining a gel; and aging, crystallizing and calcining the gel to obtain the SSZ-39 molecular sieve, wherein the oxygen-containing substance comprises one or a combination of two or more of an alcohol, a ketone, an ether and a polyhydric alcohol. The application also provides the SSZ-39 molecular sieve obtained by the above preparation method and a DeNOx reaction catalyst comprising or made of the SSZ-39 molecular sieve. The above preparation method provided by the application can effectively reduce the grain size of the SSZ-39 molecular sieve, especially the thickness of the grain, and further improve the catalytic activity of the molecular sieve by adding the oxygen-containing substance in the raw materials.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve synthesis technology, and in particular to an SSZ-39 molecular sieve, its preparation method, and a DeNOx reaction catalyst. Background Technology

[0002] SSZ-39 molecular sieve is a molecular sieve with an AEI topology. It consists of AlO4 and SiO4 tetrahedra connected end-to-end by oxygen atoms, forming a secondary structural unit (SBU) of double six-membered rings. Adjacent layers of these double six-membered rings rotate 180° around the z-axis and are arranged in a staggered pattern. The double six-membered rings are connected by four-membered rings to form an AEI cage (an asymmetric pear-shaped cage) with an eight-membered ring structure and a three-dimensional channel structure. The channel size is... Due to its ordered pore structure, high specific surface area, good hydrothermal stability, numerous surface proton acid centers, and excellent cation exchangeability, SSZ-39 molecular sieve has demonstrated excellent performance in industrial catalytic processes such as NH3- selective catalytic reduction (NH3-SCR) and methanol-to-olefins (MTO) in recent years.

[0003] Typically, SSZ-39 molecular sieves synthesized via conventional hydrothermal synthesis methods generally have relatively large crystal sizes, typically 1-3 μm. Zeolite crystal size has a significant impact on the reaction. Compared to zeolites of conventional sizes, smaller crystallites exhibit a marked change in specific surface area, particularly an increase in external specific surface area. This is because as the crystal size decreases, a large number of previously unexposed surfaces in the bulk phase become exposed, thus significantly increasing the external specific surface area. For SCR reactions, AEI zeolites have a longer run time, resulting in better resistance to carbon deposition. Since AEI zeolites typically have a cuboid morphology, shortening one dimension can effectively reduce the diffusion length and weaken the carbon deposition effect.

[0004] Existing methods for controlling the morphology of molecular sieves focus on regulating the overall particle size. These studies typically involve adding large amounts of additives to form a spatial framework outside the crystal, thereby limiting the overall crystal growth. Currently, there is a lack of methods for controlling the size of molecular sieves in specific crystal orientations. Therefore, it is necessary to propose a method to reduce the size of SSZ-39 zeolite crystals in specific directions. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide an SSZ-39 molecular sieve, its preparation method, and a DeNOx reaction catalyst. This preparation method, by adding oxygen-containing substances to the raw materials, can effectively reduce the crystal size, especially the crystal thickness, of the SSZ-39 molecular sieve, thereby improving the catalytic activity of the molecular sieve.

[0006] To achieve the above objectives, the present invention provides a method for preparing SSZ-39 molecular sieve, wherein the preparation method includes: mixing a silicon source, an aluminum source, an alkali source, an organic template agent, an oxygen-containing substance, and water, aging the mixture to obtain a gel; crystallizing and calcining the gel to obtain the SSZ-39 molecular sieve; wherein the oxygen-containing substance includes one or more combinations of alcohols, ketones, ethers, and polyols, and the oxygen-containing substance has 4 or more carbon atoms.

[0007] The crystallization of molecular sieves typically involves the following processes: condensation polymerization of silicon (e.g., silicates) and aluminum (e.g., aluminates), molecular sieve nucleation, molecular sieve crystal growth, and metastable phase transformation. The condensation polymerization of silicon and aluminum is integral to the entire molecular sieve synthesis process. This invention has discovered that oxygen-containing substances added to the raw materials can participate in the condensation polymerization of silicon and aluminum. These oxygen-containing substances, by adsorbing onto specific crystal faces of the molecular sieve, can reduce the growth rate of the molecular sieve on a particular crystal plane, thereby controlling the size of the molecular sieve. Specifically, since the crystal faces of the molecular sieve have different sizes, this invention selects oxygen-containing substances with a certain molecular weight and containing oxygen-containing functional groups. This allows the oxygen-containing substances to preferentially adhere to larger crystal faces, significantly reducing the growth rate and size of crystal faces perpendicular to the adsorbed crystal face. The larger the molecular weight of the oxygen-containing substance, the more significant the reduction in the growth rate and size of specific crystal faces.

[0008] According to a specific embodiment of the present invention, the oxygen-containing substance has 4-12 carbon atoms, for example, at least one of the alcohols, ketones, and ethers has 4-12 carbon atoms. Specifically, the number of carbon atoms in the oxygen-containing substance can be 4, 5, 6, 7, 8, 9, 10, 11, 12, etc., or a range with any two of the above specific values ​​as endpoints.

[0009] According to a specific embodiment of the present invention, among the above-mentioned oxygen-containing substances, the alcohol may include one or a combination of two or more of butanediol, n-octanol, dodecanol, lauryl alcohol, cedrol, and phytol.

[0010] According to a specific embodiment of the present invention, among the above-mentioned oxygen-containing substances, the ketone may include one or a combination of two or more of 2-adamantanone, benzophenone, and anthrone.

[0011] According to a specific embodiment of the present invention, in the above-mentioned oxygen-containing substances, the ether may include one or a combination of two or more of diphenyl ether, dibenzyl ether, diethylene glycol dibutyl ether and bis(2-bromoethyl) ether;

[0012] According to a specific embodiment of the present invention, the polyol in the above-mentioned oxygen-containing substances may include one or more of polycaprolactone diol, fatty alcohol polyoxyethylene ether, and polyether polyol.

[0013] In the above preparation method, the silicon source may include one or more of silicon dioxide, silicates, orthosilicates, kaolin, and bentonite. In some specific embodiments, the silicate may include solid water glass and / or liquid water glass, etc.; the silicon dioxide may include silica sol and / or silicon powder, etc.

[0014] In the above preparation method, the aluminum source may include one or more of the following: USY molecular sieve, NaY molecular sieve, ZSM-5 molecular sieve, Beta molecular sieve, sodium aluminate, aluminum hydroxide, boehmite, aluminum isopropoxide, aluminum sol, and boehmite.

[0015] In the above preparation method, the organic template agent may include a piperidine derivative template agent. Specifically, the organic template agent comprises one or more combinations of compounds capable of providing 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 cation. In some specific embodiments, the organic template agent includes one or more combinations of N,N-diethyl-2,6-dimethylhydropiperidine, 3,5-dimethyl-N,N-dimethylhydropiperidine, and N,N-dimethyl-N,N-bicyclononane, for example, N,N-dimethyl-N,N-bicyclononane and one of the following two: N,N-diethyl-2,6-dimethylhydropiperidine or 3,5-dimethyl-N,N-dimethylhydropiperidine.

[0016] In the above preparation method, the alkali may include sodium hydroxide and / or potassium hydroxide, etc., and sodium hydroxide is preferred.

[0017] In the above preparation method, let R be the molar number of the organic template agent and A be the molar number of the oxygen-containing substance. The chemical composition of the gel satisfies the following molar ratio range: SiO2 / Al2O3 = 5-200, OH - / SiO2=0-2, H2O / SiO2=2-80, R / SiO2=0-0.5, A / SiO2=0.0001-1; where silicon source is calculated as silicon dioxide, aluminum source as aluminum oxide, and alkali as hydroxide ions.

[0018] In some specific implementations, the silicon source is calculated as silicon dioxide and the aluminum source as aluminum oxide. The molar ratio of the silicon source to the aluminum source is generally SiO2 / Al2O3 = 5-200, for example, SiO2 / Al2O3 = 5-30. Specifically, SiO2 / Al2O3 can be specific values ​​such as 5, 10, 20, 30, 40, 45, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, etc., as well as a range with any two of the above specific values ​​as endpoints.

[0019] In some specific implementations, the silicon source is calculated as silicon dioxide and the alkali as hydroxide ions, and the molar ratio of the silicon source to the alkali can be controlled to OH. - / SiO2 = 0 - 2 (greater than 0 and less than or equal to 2), for example, OH - / SiO2=0-0.5. Specifically, OH - / SiO2 can be a specific value such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or a range with any two of the above specific values ​​as endpoints.

[0020] In some specific implementations, the silicon source is based on silicon dioxide, and the molar ratio of the silicon source to water can be controlled to H2O / SiO2 = 2-80, for example, H2O / SiO2 = 5-40. Specifically, H2O / SiO2 can be specific values ​​such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, etc., as well as a range with any two of the above specific values ​​as endpoints.

[0021] In some specific implementations, the silicon source is measured in silica, and the molar number of the organic template agent is denoted as R. The molar ratio of the silicon source to the organic template agent can be controlled to R / SiO2 = 0-0.5 (greater than 0 and less than or equal to 0.5), for example, R / SiO2 = 0-0.2. Specifically, R / SiO2 can be specific values ​​such as 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc., or a range with any two of the above specific values ​​as endpoints.

[0022] In some specific implementations, the silicon source is measured in silicon dioxide, and the molar number of oxygen-containing substances is denoted as A. The molar ratio of the silicon source to the oxygen-containing substances can be controlled to A / SiO2 = 0.0001-1, for example, A / SiO2 = 0.0001-0.1. Specifically, A / SiO2 can be specific values ​​such as 0.0001, 0.0005, 0.001, 0.005, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.5, 1, etc., as well as a range with any two of the above specific values ​​as endpoints.

[0023] In the above preparation method, the aging temperature is from room temperature to 100°C, and the aging time is 0.1-100 hours. Further, the aging time can be controlled to be 1-2 hours.

[0024] In the above preparation method, the crystallization temperature is 120-210℃, for example, it can be a specific value such as 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, etc., or a range with any two of the above specific values ​​as endpoints.

[0025] In the above preparation method, the crystallization time can be 38-150h, and can be further controlled to 50-130h.

[0026] In the above preparation method, the calcination temperature is 400-800℃ and the calcination time is 2h-6h, preferably 500℃-600℃, and the calcination time is 2h-4h.

[0027] According to a specific embodiment of the present invention, the above preparation method may further include stirring during the mixing process, wherein the stirring time may be 0-3 hours and the stirring temperature may be 30-50°C.

[0028] According to a specific embodiment of the present invention, the above preparation method may further include stirring the gel before crystallization. The stirring time may be 0-20 h, or more specifically 0.5-20 h, 0.5-10 h, 10-20 h, etc. The stirring temperature may be room temperature. The stirring method may be gel rotation.

[0029] According to a specific embodiment of the present invention, the above preparation method may further include cooling, filtering, washing, and drying operations performed sequentially after crystallization and before calcination.

[0030] According to a specific embodiment of the present invention, the above preparation method may specifically include:

[0031] 1. Mix silicon source, aluminum source, alkali source, organic template agent, oxygen-containing substance and water, and age at room temperature to 100℃ for 0.1-100h to obtain gel; wherein, after adding oxygen-containing substance, stir at 30-50℃ for 0-3h.

[0032] The chemical composition of the gel meets the following molar ratio range: SiO2 / Al2O3 = 5-200, OH - / SiO2=0-2, H2O / SiO2=2-80, R / SiO2=0-0.5, A / SiO2=0.0001-1;

[0033] Oxygen-containing substances include one or more of alcohols, ketones, ethers, and polyols;

[0034] 2. Stir the gel for 0-10 hours (specifically by rotation); keep stirring and heat the gel to 120-210℃ for 38-150 hours to crystallize; cool the crystallized product, filter, wash, dry, and calcine at 500℃-600℃ for 2-6 hours to obtain the SSZ-39 molecular sieve.

[0035] The present invention also provides an SSZ-39 molecular sieve, which is obtained by the above-described preparation method of SSZ-39 molecular sieve.

[0036] According to specific implementation schemes, the thickness of the SSZ-39 molecular sieve provided by this invention is significantly reduced compared to conventional SSZ-39 molecular sieves. The thickness of the SSZ-39 molecular sieve of this invention can be 0.1-10 μm, and can further reach 0.1-4 μm, 0.1-2 μm, 0.1-0.5 μm, etc. Specifically, the thickness of the SSZ-39 molecular sieve can be specific values ​​such as 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, etc., and a range with any two of the above specific values ​​as endpoints.

[0037] According to a specific implementation scheme, the length of the SSZ-39 molecular sieve of the present invention can be 1-2 μm. Specifically, the length of the SSZ-39 molecular sieve can be a specific value such as 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, or a range with any two of the above specific values ​​as endpoints.

[0038] This invention also provides a DeNOx reaction catalyst comprising the aforementioned SSZ-39 molecular sieve, or the raw material for the DeNOx reaction catalyst comprising the aforementioned SSZ-39 molecular sieve. The SSZ-39 molecular sieve provided by this invention has adjustable dimensions, particularly a significantly reduced thickness, thereby shortening the diffusion path of molecules within the SSZ-39 molecular sieve and improving its catalytic activity. In some specific embodiments, the SSZ-39 molecular sieve can be used as a catalyst in the NH3-SCR reaction at a reaction temperature of 150-600℃.

[0039] The beneficial effects of this invention include: by introducing oxygen-containing substances during the synthesis process, the grain size, especially the thickness dimension, can be effectively reduced, resulting in SSZ-39 molecular sieves with smaller grain thickness. The diffusion paths of molecules in this molecular sieve are shorter, carbon deposition is significantly improved, and catalytic activity is enhanced, making it suitable for use as a DeNOx reaction catalyst. Attached Figure Description

[0040] Figure 1 The image shows the SEM image of the SSZ-39 molecular sieve from Example 1.

[0041] Figure 2 This is a SEM image of the SSZ-39 molecular sieve from Example 2.

[0042] Figure 3 This is a SEM image of the SSZ-39 molecular sieve from Example 3.

[0043] Figure 4 This is a SEM image of the SSZ-39 molecular sieve from Example 4.

[0044] Figure 5 The image shows the SEM image of the SSZ-39 molecular sieve in Comparative Example 1.

[0045] Figure 6 The image shows the SEM image of SSZ-39 molecular sieve in Comparative Example 2.

[0046] Figure 7 The XRD patterns are of the SSZ-39 molecular sieves prepared in Examples 1 to 4 and Comparative Examples 1 to 2. Detailed Implementation

[0047] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0048] Example 1

[0049] This embodiment provides an SSZ-39 molecular sieve, the preparation method of which includes:

[0050] 1. Sodium hydroxide, pure water, silica sol with a concentration of 40 wt% silica, an aqueous solution of 3,5-dimethyl-N,N-dimethylhydropiperidine (as an organic template agent) with a concentration of 25 wt%, dodecanol, and USY molecular sieve were thoroughly mixed and aged at room temperature for 1 hour to obtain a gel. The chemical composition of the gel met the following molar ratio:

[0051] SiO2 / Al2O3 = 60,

[0052] Organic template agent / SiO2 = 0.2

[0053] Dodecanol / SiO2 = 0.02

[0054] OH - / SiO2=0.7,

[0055] H2O / SiO2 = 20.

[0056] 2. Place the gel into an autoclave, stir at room temperature for 0.5 hours, and then heat to 160°C to crystallize for 50 hours.

[0057] 3. After crystallization, the crystallized product is cooled to below 40°C, filtered, washed, and the solid is dried and calcined at 550°C for 4 hours to obtain SSZ-39 molecular sieve.

[0058] Figure 1 The image shows an SEM image of the SSZ-39 molecular sieve sample from this embodiment. The sample is approximately 1.0 μm-1.5 μm long and 0.2 μm-0.5 μm thick.

[0059] Example 2

[0060] This embodiment provides an SSZ-39 molecular sieve, the preparation method of which includes:

[0061] 1. Sodium hydroxide, pure water, silica sol with a concentration of 40 wt% silica, an aqueous solution of 3,5-dimethyl-N,N-dimethylhydropiperidine (as an organic template agent) with a concentration of 25 wt%, 2-adamantanone, and USY molecular sieve were thoroughly mixed and aged at room temperature for 1 hour to obtain a gel. The chemical composition of the gel met the following molar ratio:

[0062] SiO2 / Al2O3 = 60,

[0063] Organic template agent / SiO2 = 0.2

[0064] 2-Adamantane / SiO2 = 0.01

[0065] OH - / SiO2=0.5,

[0066] H2O / SiO2 = 20.

[0067] 2. The synthesized gel was placed in an autoclave and stirred at room temperature for 0.5 hours, then heated to 180°C and crystallized for 60 hours.

[0068] 3. After crystallization, the crystallized product is cooled to below 40°C, filtered, washed, and the solid is dried and calcined at 550°C for 4 hours to obtain SSZ-39 molecular sieve.

[0069] The SEM image of the sample is as follows Figure 2 As shown, the sample's length is approximately 1.0 μm-1.8 μm and its thickness is approximately 0.2 μm-0.3 μm.

[0070] Example 3

[0071] This embodiment provides an SSZ-39 molecular sieve, the preparation method of which includes:

[0072] Sodium hydroxide, pure water, silica sol with a concentration of 40 wt%, 3,5-dimethyl-N,N-dimethylhydropiperidine (as an organic template agent) aqueous solution with a concentration of 25 wt%, dibenzyl ether, and USY molecular sieve were thoroughly mixed and aged at room temperature for 1 hour to obtain a gel. The chemical composition of the gel met the following molar ratio:

[0073] SiO2 / Al2O3 = 45,

[0074] Organic template agent / SiO2 = 0.2

[0075] Dibenzyl ether / SiO2 = 0.08

[0076] OH - / SiO2=0.5,

[0077] H2O / SiO2 = 20.

[0078] 2. The synthesized gel was placed in an autoclave and stirred at room temperature for 0.5 hours, then heated to 170°C and crystallized for 40 hours.

[0079] 3. After crystallization, the crystallized product is cooled to below 40°C, filtered, washed, and the solid is dried and calcined at 550°C for 4 hours to obtain SSZ-39 molecular sieve.

[0080] The SEM image of the sample is as follows Figure 3 As shown, the sample's length is approximately 1.0 μm-1.5 μm and its thickness is approximately 0.15 μm-0.3 μm.

[0081] Example 4

[0082] This embodiment provides an SSZ-39 molecular sieve, the preparation method of which includes:

[0083] Sodium hydroxide, pure water, silica sol with a concentration of 40 wt%, 3,5-dimethyl-N,N-dimethylhydropiperidine aqueous solution with a concentration of 25 wt% (as an organic template agent), polyether polyol 560s (manufactured by Shanghai Gaoqiao Petrochemical Co., Ltd.), and USY molecular sieve were thoroughly mixed and aged at room temperature for 1 hour to obtain a gel. The chemical composition of the gel met the following molar ratio:

[0084] SiO2 / Al2O3 = 45,

[0085] Organic template agent (SDA) / SiO2 = 0.2

[0086] Polyether polyol 560s / SiO2 = 0.01

[0087] OH - / SiO2=0.5,

[0088] H2O / SiO2 = 20.

[0089] 2. The synthesized gel was placed in an autoclave and stirred at room temperature for 0.5 hours, then heated to 170°C and crystallized for 40 hours.

[0090] 3. After crystallization, the crystallized product is cooled to below 40°C, filtered, washed, and the solid is dried and calcined at 550°C for 4 hours to obtain SSZ-39 molecular sieve.

[0091] The SEM image of the sample is as follows Figure 4 As shown, the sample's length is approximately 1.0 μm-1.8 μm and its thickness is approximately 0.2 μm-0.4 μm.

[0092] Comparative Example 1

[0093] This comparative example provides an SSZ-39 molecular sieve, the preparation method of which includes:

[0094] Sodium hydroxide, pure water, silica sol with a concentration of 40 wt% silica, an aqueous solution of 3,5-dimethyl-N,N-dimethylhydropiperidine (as an organic template agent) with a concentration of 25 wt% aqueous solution, and USY molecular sieve were thoroughly mixed and aged at room temperature for 1 h to obtain a gel. The chemical composition of the gel met the following molar ratio:

[0095] SiO2 / Al2O3 = 45,

[0096] Organic template agent / SiO2 = 0.2

[0097] OH - / SiO2=0.5,

[0098] H2O / SiO2 = 20.

[0099] 2. The synthesized gel was placed in an autoclave and stirred at room temperature for 0.5 hours, then heated to 160°C and crystallized for 50 hours.

[0100] 3. After crystallization, the crystallized product is cooled to below 40°C, filtered, washed, and the solid is dried and calcined at 550°C for 4 hours to obtain SSZ-39 molecular sieve.

[0101] Figure 5 This is a SEM image of the SSZ-39 molecular sieve sample used in this comparative example. The sample is approximately 3μm-4.5μm long and 1μm-3μm thick.

[0102] Comparative Example 2

[0103] This comparative example provides an SSZ-39 molecular sieve, the preparation method of which includes:

[0104] Sodium hydroxide, pure water, silica sol with a concentration of 40 wt% silica, an aqueous solution of 3,5-dimethyl-N,N-dimethylhydropiperidine (as an organic template agent) with a concentration of 25 wt%, ethanol, and USY molecular sieve were thoroughly mixed and aged at room temperature for 1 hour to obtain a gel. The chemical composition of the gel met the following molar ratio:

[0105] SiO2 / Al2O3 = 45,

[0106] Organic template agent / SiO2 = 0.2

[0107] Ethanol / SiO2 = 0.05

[0108] OH - / SiO2=0.5,

[0109] H2O / SiO2 = 20.

[0110] 2. The synthesized gel was placed in an autoclave and stirred at room temperature for 0.5 hours, then heated to 160°C and crystallized for 50 hours.

[0111] 3. After crystallization, the crystallized product is cooled to below 40°C, filtered, washed, and the solid is dried and calcined at 550°C for 4 hours to obtain SSZ-39 molecular sieve.

[0112] Figure 6 This is a SEM image of the SSZ-39 molecular sieve sample used in this comparative example. The sample is approximately 3-4 μm long and 1-3 μm thick.

[0113] Figure 7 The images show the XRD patterns of the SSZ-39 molecular sieves prepared in Examples 1 to 4 and Comparative Examples 1 to 2. Figure 7 As can be seen from the examples, the molecular sieve samples prepared in each embodiment and comparative example all belong to the pure phase SSZ-39 molecular sieve.

[0114] Test Example 1

[0115] This test example provides NH3-SCR reaction performance tests for SSZ-39 molecular sieve samples prepared in Examples 1 to 4 and Comparative Examples 1 to 2. Specific test methods include:

[0116] (1) Ammonium exchange of molecular sieves: The SSZ-39 molecular sieves prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were used as test samples. Ammonium nitrate, molecular sieve, and water were mixed in a mass ratio of 1:1:10. The pH was adjusted to 8-8.5 using ammonia water. The mixture was exchanged at 90°C for 1 hour with stirring. After filtration, washing, drying, and calcination at 550°C for 4 hours, the process was repeated three times until the Na₂O content in the molecular sieve was less than 0.1%.

[0117] (2) Molecular sieve copper loading: Dissolve copper acetate equivalent to 5% CuO loading of molecular sieve in 50 times the amount of water, add the molecular sieve that has undergone ammonium exchange under stirring, adjust the pH to 8-8.5 with ammonia water, filter, wash, dry, and calcine at 550℃ for 4 hours.

[0118] (3) The Cu-SSZ-39 composite molecular sieves prepared by ammonium exchange and Cu loading in Examples 1 to 4 and Comparative Examples 1 to 2 were pressed into tablets, pulverized, and sieved. After hydrothermal aging at 650°C for 100 h in an atmosphere of 10% H2O and 90% nitrogen, 0.5 g of a 40-60 mesh sample was taken for NH3-SCR reaction. The composition of the reaction mixture was: 1000 ppm NO, 1100 ppm NH3, 10 vol% O2, 10 vol% H2O, with N2 as the equilibrium gas and a volume hourly space velocity of 120,000 h⁻¹. -1 The reaction temperature is 150℃-600℃, and the NOx concentration in the exhaust gas is detected online using an MKS infrared gas analyzer.

[0119] NO x Conversion rate is defined as:

[0120]

[0121] Among them, [NO] in To determine the concentration of NO in the reaction mixture, [NO] out [NO2] represents the concentration of NO in the exhaust gas. out[N2O] represents the concentration of NO2 in the exhaust gas. out This represents the concentration of N2O in the exhaust gas.

[0122] Table 1 shows the conversion rates of nitrogen oxides in the reaction mixture at different temperatures (150-350℃).

[0123] Table 1

[0124] 150℃，％ 350℃，％ 550℃，％ Example 1 67 97 96 Example 2 66 97 96 Example 3 65 96 96 Example 4 64 98 95 Comparative Example 1 52 95 93 Comparative Example 2 51 95 92

[0125] As can be seen from Table 1, compared with the addition of oxygen-containing substances in the raw materials and the addition of oxygen-containing substances with too small molecular weight (too few carbons), the SSZ-39 molecular sieve synthesized using oxygen-containing substances provided by this invention has a higher nitrogen oxide conversion rate in the range of 150-550℃ than the SSZ-39 molecular sieve synthesized without the addition of oxygen-containing substances at the same temperature. This indicates that adding oxygen-containing substances to the raw materials can effectively improve the DeNOx activity of SSZ-39 molecular sieve.

[0126] The above results demonstrate that the present invention can prepare pure-phase SSZ-39 molecular sieves with reduced thickness by using oxygen-containing substances as additives, thereby improving the DeNOx activity of SSZ-39 molecular sieves and improving carbon deposition. The preparation method of this SSZ-39 molecular sieve is simple and has low production cost, and has good prospects for promotion.

Claims

1. A method of making a SSZ-39 molecular sieve, wherein, The preparation method comprises: mixing a silicon source, an aluminum source, an alkali source, an organic template agent, an oxygen-containing substance and water, aging to obtain a gel; crystallizing and calcining the gel to obtain the SSZ-39 molecular sieve; The oxygen-containing substance comprises one or more than two combinations of alcohol, ketone, ether and polyhydric alcohol, and the number of carbon atoms of the oxygen-containing substance is greater than or equal to 4. The alcohol comprises one or more than two combinations of butanediol, n-octanol, dodecanol, lauryl alcohol, cedrol and phytol. The ketone comprises one or more than two combinations of 2-adamantanone, benzophenone and anthracene ketone. The ether comprises one or more than two combinations of diphenyl ether, benzyl ether, diethylene glycol dibutyl ether and bis (2-bromoethyl) ether. The polyhydric alcohol comprises one or more than two combinations of polycaprolactone diol and polyether polyol.

2. The production method according to claim 1, wherein The number of carbon atoms of the oxygen-containing substance is 4-12.

3. The production method according to claim 1, wherein The silicon source comprises one or more than two combinations of silicon dioxide, silicate, orthosilicate, kaolin and bentonite.

4. The production method according to claim 3, wherein The silicate comprises solid water glass and / or liquid water glass; and the silicon dioxide comprises silica sol and / or silicon powder.

5. The production method according to claim 1, wherein The aluminum source comprises one or more than two combinations of USY molecular sieve, NaY molecular sieve, ZSM-5 molecular sieve, Beta molecular sieve, sodium metaaluminate, aluminum hydroxide, pseudo-boehmite, aluminum isopropyl alcohol, aluminum sol and boehmite.

6. The production method according to claim 1, wherein The organic template agent comprises a piperidine derivative template agent.

7. The production method according to claim 1, wherein The organic template agent comprises one or more than two combinations of compounds capable of providing the following ions: 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 cation.

8. The production method according to claim 1, wherein The organic template agent comprises one or more than two combinations of N,N-diethyl-2,6-dimethylpiperidinium, 3,5-dimethyl-N,N-dimethylpiperidinium and N,N-dimethyl-N,N-bicyclononane.

9. The method of making according to any one of claims 1-8, wherein, The molar number of the organic template agent is R, and the molar number of the oxygen-containing substance is A, and the chemical composition of the gel satisfies the following molar ratio range: SiO2 / Al2O3 = 5-200, OH - / SiO2 is greater than 0 and less than or equal to 2, H2O / SiO2 = 2-80, R / SiO2 is greater than 0 and less than or equal to 0.5, A / SiO2 = 0.0001-1.

10. The production method according to claim 9, wherein The chemical composition of the gel satisfies the following molar ratio range: SiO2 / Al2O3=5-30.

11. The production method according to claim 9, wherein The chemical composition of the gel satisfies the following molar ratio ranges: OH - / SiO2 is greater than 0 and less than or equal to 0.

5.

12. The production method according to claim 9, wherein, The chemical composition of the gel satisfies the following molar ratio range: H2O / SiO2=5-40.

13. The production method according to claim 9, wherein The chemical composition of the gel satisfies the following molar ratio range: R / SiO2 is greater than 0 and less than or equal to 0.

2.

14. The production method according to claim 9, wherein The chemical composition of the gel satisfies the following molar ratio ranges: A / SiO2=0.0001-0.

1.

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

16. The method of manufacturing according to claim 15, wherein, The aging time is 1-2h.

17. The method of producing according to claim 1, wherein, The crystallization temperature is 120-210°C, and the crystallization time is 38-150h.

18. The method of making according to claim 17, wherein, The crystallization time is 50-130h.

19. An SSZ-39 molecular sieve obtained by the preparation method of any one of claims 1-18.

20. The SSZ-39 molecular sieve of claim 19, wherein, The thickness of the SSZ-39 molecular sieve is 0.1-10μm, and the length of the SSZ-39 molecular sieve is 1-2μm.

21. The SSZ-39 molecular sieve of claim 20, wherein, The thickness of the SSZ-39 molecular sieve is 0.1-4μm.

22. The SSZ-39 molecular sieve of claim 20, wherein, The thickness of the SSZ-39 molecular sieve is 0.1-2μm.

23. The SSZ-39 molecular sieve of claim 20, wherein, The thickness of the SSZ-39 molecular sieve is 0.1-0.5μm.

24. A DeNOx reaction catalyst comprising the SSZ-39 molecular sieve of any one of claims 19-23, or a raw material of the DeNOx reaction catalyst comprising the SSZ-39 molecular sieve of any one of claims 19-23.

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