A method of making ssz-13 molecular sieve

Abstract

The application provides a preparation method of SSZ-13 molecular sieve and relates to the technical field of molecular sieve preparation.The preparation process of the SSZ-13 molecular sieve comprises the following steps: mixing an aluminum source and an alkali source in a water environment, adding a tetravalent silicon source to obtain a reaction gel, and then performing a hydrothermal crystallization reaction; and after the reaction is completed, the reaction slurry obtained is filtered, washed, dried and calcined to obtain the SSZ-13 molecular sieve.The SSZ-13 molecular sieve preparation method provided by the application does not need to use an organic structure template agent, simplifies the process flow, reduces the production cost, improves the product quality and environmental protection, meets the green chemistry requirements, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve preparation technology, and in particular to a method for preparing SSZ-13 molecular sieve. Background Technology

[0002] SSZ-13 is a CHA (Chabazite) type zeolite molecular sieve with a crystal structure composed of an 8-membered ring channel system. This structure endows it with high selectivity and stability. Simultaneously, its high specific surface area and silicon-to-aluminum ratio contribute to its excellent catalytic performance, good hydrothermal stability, high surface proton acidity, and exchangeable cations. Therefore, it exhibits superior performance in NOx removal (DeNOx) from diesel vehicle exhaust, methanol-to-olefins (MTO), and CO2 adsorption and separation.

[0003] SSZ-13 was originally invented by Zones of Chevron Corporation in 1985. It is prepared using the conventional hydrothermal method with N,N,N-trimethyl-1-adamantyl ammonium hydroxide (TMAdaOH) as a template agent.

[0004] US Patent 4544538 first disclosed a method for synthesizing SSZ-13 molecular sieve, which uses N,N,N-trimethyl-1-adamantaneamine (TMAA). + Organic cations were used as template agents to synthesize SSZ-13 molecular sieves. However, N,N,N-trimethyl-1-adamantaneamine was expensive, resulting in excessively high synthesis costs for SSZ-13 molecular sieves, which severely limited their industrial applications.

[0005] US Patent 60 / 826882, filed by Zone on September 25, 2006, describes a method to reduce the use of N,N,N-trimethyl-1-adamantaneamine organic cations as template agents. This method significantly reduces the use of N,N,N-trimethyl-1-adamantaneamine cations by adding benzyltrimethylammonium cations (such as benzyltrimethylammonium hydroxide). While this method reduces the use of N,N,N-trimethyl-1-adamantaneamine cations and thus lowers the synthesis cost of SSZ-13 molecular sieves, it cannot completely avoid TMAA (trimethylammonium hydroxide). + The use of.

[0006] The invention patent with publication number CN111484037A discloses a method for synthesizing SSZ-13 molecular sieves with different silica-alumina ratios by transcrystallization of Y molecular sieves. This method involves adding Y molecular sieves with different silica-alumina ratios to the initial gel, and then adding the structure-directing agent N,N,N-trimethyl-1-adamantylamine hydroxide under high temperature hydrothermal conditions to transcrystallize the Y molecular sieves into SSZ-13 molecular sieves with different silica-alumina ratios. However, this method still cannot avoid the use of organic structure-directing agents. Summary of the Invention

[0007] In view of this, the present invention provides a method for preparing SSZ-13 molecular sieve. This method does not require the use of organic structural template agents and has significant advantages in terms of process simplification, cost reduction, product quality improvement and environmental protection. Compared with the prior art, it has good application prospects.

[0008] The preparation method of the SSZ-13 molecular sieve of the present invention includes the following steps:

[0009] Aluminum source and alkali source are mixed evenly in an aqueous environment, and then tetravalent silicon source is added and stirred to react to obtain a reaction gel. The reaction gel is then subjected to a hydrothermal crystallization reaction. After the reaction is completed, the resulting reaction slurry is filtered, washed, dried and calcined to obtain SSZ-13 molecular sieve.

[0010] Preferably, the aluminum source is at least one of sodium aluminate, aluminum sulfate, aluminum nitrate, boehmite, and aluminum chloride.

[0011] Preferably, the alkali source is NaOH and / or KOH.

[0012] Preferably, the tetravalent silicon source is at least one selected from silicates, silica sols, tetraethyl orthosilicates, deposited silica, and clay. More preferably, the tetravalent silicon source is a silica sol.

[0013] Preferably, the molar ratio of the tetravalent silicon source to the aluminum source is 1:(2-50), the molar ratio of the tetravalent silicon source to the alkali metal element is 1:(0.05-0.2), and the molar ratio of the tetravalent silicon source to hydroxide ions is 1:(0.2-0.7).

[0014] Preferably, the stirring reaction time is 1 to 3 hours.

[0015] Preferably, the hydrothermal crystallization reaction temperature is 100℃~200℃, and the hydrothermal crystallization reaction time is 72~96h.

[0016] Preferably, the drying temperature is 80℃~120℃ and the drying time is 10~20h.

[0017] Preferably, the calcination temperature is 450℃~600℃ and the calcination time is 2~6h.

[0018] The SSZ-13 molecular sieve preparation method of this invention eliminates the need for traditional template agents such as N,N,N-trimethyl-1-adamantaneamine cation and benzyltrimethylammonium cation, avoiding the pollution problems associated with template agents, reducing production costs, and simplifying the process. This invention improves process flexibility by selecting different combinations of aluminum, alkali, and tetravalent silicon sources, allowing adjustment of reaction conditions according to specific needs to obtain the desired SSZ-13 molecular sieve. Simultaneously, by precisely controlling the ratio of aluminum, tetravalent silicon, and alkali sources, this invention optimizes the temperature and time of the hydrothermal crystallization reaction, as well as the drying and calcination temperatures, effectively improving crystallinity and yield, and ensuring product quality consistency. The use of common aluminum and alkali sources not only reduces raw material costs but also further reduces production costs due to the absence of expensive template agents. Furthermore, the absence of organic template agents reduces environmental pollution risks, meeting the requirements of green chemistry and improving environmental performance. In the SSZ-13 molecular sieve preparation process of this invention, the reaction time and temperature of hydrothermal crystallization and calcination are controllable, contributing to improved production efficiency and ensuring product consistency. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings.

[0020] Figure 1 The PXRD pattern of the SSZ-13 molecular sieve synthesized in Example 1;

[0021] Figure 2 The PXRD pattern of the SSZ-13 molecular sieve synthesized in Example 2;

[0022] Figure 3 The PXRD pattern of the SSZ-13 molecular sieve synthesized in Example 3 is shown below.

[0023] Figure 4 The PXRD pattern of the SSZ-13 molecular sieve synthesized in Example 4 is shown below.

[0024] Figure 5 The PXRD pattern of the SSZ-13 molecular sieve synthesized in Example 5 is shown. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] This invention provides a method for preparing SSZ-13 molecular sieve, comprising the following steps:

[0027] S1. Mix the aluminum source and the alkali source evenly in an aqueous environment, then add the tetravalent silicon source and stir to react, thus obtaining a reaction gel;

[0028] S2. Separate the crystals after hydrothermal crystallization of the reaction gel;

[0029] S3. After washing the crystals with water until neutral, dry and calcine to obtain SSZ-13 molecular sieve.

[0030] The aluminum source described in this invention is preferably at least one of sodium aluminate, aluminum sulfate, aluminum nitrate, boehmite, and aluminum chloride.

[0031] The preferred alkali source in this invention is NaOH and / or KOH.

[0032] The tetravalent silicon source described in this invention is preferably at least one of silicate, silica sol, tetraethyl orthosilicate, deposited silica, and clay. In some specific embodiments of this invention, the tetravalent silicon source is silica sol. In some preferred embodiments of this invention, the silica sol is AS-40 silica sol.

[0033] The preferred molar ratio of the tetravalent silicon source to the aluminum source in this invention is 1:(2-50), the molar ratio of the tetravalent silicon source to the alkali metal element is 1:(0.05-0.2), and the molar ratio of the tetravalent silicon source to hydroxide ions is 1:(0.2-0.7).

[0034] The preferred stirring reaction time according to the present invention is 1 to 3 hours.

[0035] In some preferred embodiments of the present invention, an aluminum source and an alkali source are mixed evenly in an aqueous environment and stirred for 1 hour, and then a tetravalent silicon source is added and stirred to react, thereby obtaining a reaction gel.

[0036] The hydrothermal crystallization reaction temperature of the present invention is preferably 100℃~200℃, and the hydrothermal crystallization reaction time is preferably 72~96h. In some preferred embodiments of the present invention, the hydrothermal crystallization reaction time is 140℃~160℃, and the hydrothermal crystallization reaction time is 72h. In some more preferred embodiments of the present invention, the hydrothermal crystallization reaction temperature is 150℃, and the hydrothermal crystallization reaction time is 72h.

[0037] The hydrothermal crystallization reaction described in this invention is preferably a dynamic hydrothermal crystallization reaction.

[0038] The hydrothermal crystallization reaction described in this invention is preferably carried out in a high-pressure reactor.

[0039] The drying temperature described in this invention is preferably 80℃~120℃, and the drying time is preferably 10~20h. In some preferred embodiments of this invention, the drying temperature is 100℃, and the drying time is 12h.

[0040] The preferred calcination temperature of this invention is 450℃~600℃, and the preferred calcination time is 2~6h. In some preferred embodiments of this invention, the calcination temperature is 550℃, and the calcination time is 4h.

[0041] To further illustrate the present invention, the following embodiments are provided for detailed description. All raw materials used in the following embodiments of the present invention are commercially available.

[0042] Example 1: A method for preparing SSZ-13 molecular sieve, the steps of which are as follows:

[0043] S1. Mix 7.78g KOH and 0.35g NaOH evenly in 81.6g deionized water;

[0044] S2. Add 4.13g of pseudoboehmite to step S1 and stir for 1 hour;

[0045] S3. Add 18.66g of AS-40 to step S2 and stir for 2 hours;

[0046] S4. The reaction gel from step S3 is transferred into a crystallization vessel for crystallization treatment, and dynamically crystallized at 150°C for 72 hours.

[0047] S5. After crystallization in step S4, the reaction slurry is filtered, washed with water until neutral, dried at 100℃ for 12 hours, and calcined at 550℃ for 4 hours to obtain SSZ-13 molecular sieve. The PXRD of the sample is as follows: Figure 1 .

[0048] Example 2: A method for preparing SSZ-13 molecular sieve, the steps of which are as follows:

[0049] S1. Mix 8.2g KOH and 0.3g NaOH evenly in 81.6g deionized water;

[0050] S2. Add 3.6g of pseudoboehmite to step S1 and stir for 1 hour;

[0051] S3. Add 18.66g of AS-40 to step S2 and stir for 2 hours;

[0052] S4. The reaction gel from step S3 is transferred into a crystallization vessel for crystallization treatment, and dynamically crystallized at 150°C for 72 hours.

[0053] S5. After crystallization in step S4, the reaction slurry is filtered, washed with water until neutral, dried at 100℃ for 12 hours, and calcined at 550℃ for 4 hours to obtain SSZ-13 molecular sieve. The PXRD of the sample is as follows: Figure 2 .

[0054] Example 3: A method for preparing SSZ-13 molecular sieve, the steps of which are as follows:

[0055] S1. Mix 8.2g KOH and 0.3g NaOH evenly in 81.6g deionized water;

[0056] S2. Add 4.13g of pseudoboehmite to step S1 and stir for 1 hour;

[0057] S3. Add 18.66g of AS-40 to step S2 and stir for 2 hours;

[0058] S4. The reaction gel from step S3 is transferred into a crystallization vessel for crystallization treatment, and dynamically crystallized at 150°C for 72 hours.

[0059] S5. After crystallization in step S4, the reaction slurry is filtered, washed with water until neutral, dried at 100℃ for 12 hours, and calcined at 550℃ for 4 hours to obtain SSZ-13 molecular sieve. The PXRD of the sample is as follows: Figure 3 .

[0060] Example 4: A method for preparing SSZ-13 molecular sieve, the steps of which are as follows:

[0061] S1. Mix 8.2g KOH and 0.3g NaOH evenly in 81.6g deionized water;

[0062] S2. Add 4.38g of pseudoboehmite to step S1 and stir for 1 hour;

[0063] S3. Add 15.3g of silica to step S2 and stir for 2 hours;

[0064] S4. The reaction gel from step S3 is transferred into a crystallization vessel for crystallization treatment, and dynamically crystallized at 150°C for 72 hours.

[0065] S5. After crystallization in step S4, the reaction slurry is filtered, washed with water until neutral, dried at 100℃ for 12 hours, and calcined at 550℃ for 4 hours to obtain SSZ-13 molecular sieve. The PXRD of the sample is as follows: Figure 4 .

[0066] Example 5: A method for preparing SSZ-13 molecular sieve, the steps of which are as follows:

[0067] S1. Mix 7.5g KOH and 0.2g NaOH evenly in 81.6g deionized water;

[0068] S2. Add 4.38g of pseudoboehmite to step S1 and stir for 1 hour;

[0069] S3. Add 15.3g of silica to step S2 and stir for 2 hours;

[0070] S4. The reaction gel from step S3 is transferred into a crystallization vessel for crystallization treatment, and dynamically crystallized at 150°C for 72 hours.

[0071] S1. After crystallization in step S4, the reaction slurry was filtered, washed with water until neutral, dried at 100℃ for 12 hours, and calcined at 550℃ for 4 hours to obtain SSZ-13 molecular sieve. The PXRD of the sample is as follows: Figure 5 .

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing SZ-13 molecular sieve, characterized in that, Includes the following steps: Aluminum source and alkali source are mixed evenly in an aqueous environment, and then tetravalent silicon source is added and stirred to react to obtain reaction gel. The reaction gel is then subjected to dynamic hydrothermal crystallization reaction at 150℃ for 72 h. After the reaction is completed, the reaction slurry is filtered, washed, dried and calcined to obtain SSZ-13 molecular sieve. The molar ratio of the tetravalent silicon source to the aluminum source is 1:(2~50), the molar ratio of the tetravalent silicon source to the alkali metal element is 1:(0.05~0.2), and the molar ratio of the tetravalent silicon source to hydroxide ions is 1:(0.2~0.7). The alkali source is a mixture of NaOH and KOH.

2. The preparation method according to claim 1, characterized in that, The aluminum source is at least one of sodium aluminate, aluminum sulfate, aluminum nitrate, boehmite, and aluminum chloride.

3. The preparation method according to claim 1, characterized in that, The tetravalent silicon source is at least one of silicate, silica sol, tetraethyl orthosilicate, deposited silica, and clay.

4. The preparation method according to claim 3, characterized in that, The tetravalent silicon source is silica sol.

5. The preparation method according to claim 1, characterized in that, The stirring reaction time is 1-3 h.

6. The preparation method according to claim 1, characterized in that, The drying temperature is 80℃~120℃, and the drying time is 10~20 h.

7. The preparation method according to claim 1, characterized in that, The roasting temperature is 450℃~600℃, and the roasting time is 2~6 h.

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