Preparation method of regular square-sheet-shaped small-crystal-grain SAPO-11 molecular sieve
Through suitable raw material ratios and template agent ratios, combined with low-temperature primary crystallization and high-temperature secondary crystallization, a regular square sheet-shaped small crystallization SAPO-11 molecular sieve was successfully prepared, which solved the problems of difficult, high cost and long cycles in the prior art, and achieved efficient and low-cost molecular sieve synthesis.
Patent Information
- Application Number
- CN202411964347.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-03-11
AI Technical Summary
The method for synthesizing small particle size SAPO-11 molecular sieve in the prior art has problems such as high operation difficulty, high synthesis cost and long synthesis cycle.
By mixing deionized water, orthophosphoric acid and aluminum sources, adding a template agent and an acid silica sol, performing primary crystallization and secondary crystallization, followed by washing, drying and calculating, a regular square sheet-like small crystal SAPO-11 molecular sieve was obtained.
The synthetic pure phase molecular sieve is realized, with regular square-shaped small grains, which reduces the grain size and reduces the synthesis cost and cycle.
Smart Images
Figure CN119591124A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of molecular sieve manufacturing. Background Art
[0002] SAPO-11 molecular sieve is a type of silicoaluminophosphate molecular sieve with AEL topological structure developed by Union Carbide Corporation (UOP) in 1982, with a pore size of 0.39nm×0.64nm. Non-traditional SAPO-11 molecular sieve refers to a small-particle SAPO-11 molecular sieve obtained by a method different from the traditional one-step crystallization method, and its particle size is generally less than 2μm. The methods for synthesizing small-particle SAPO-11 molecular sieves in the prior art can be mainly divided into the following: step-by-step crystallization method, improved hydrothermal synthesis method, solvent-free method, microwave-assisted method, dry gel method, dynamic synthesis method and other methods. Various methods for synthesizing small-particle SAPO-11 molecular sieves are different. CN1356264A discloses a synthesis method in which an organic alcohol is added to the reaction system. The SAPO-11 molecular sieve has a grain size of 1 to 2 μm. This method can be used to synthesize SAPO-11 molecular sieves with smaller grains, but the addition of organic alcohols will complicate the synthesis system, increase the synthesis cost, and may also affect the acidity of the molecular sieve. Summary of the invention
[0003] In order to overcome the technical problems in the prior art of high difficulty in molecular sieve synthesis operation, high synthesis cost, long molecular sieve synthesis cycle, large size, etc., the present invention provides a preparation method of regular square plate-shaped small-grain SAPO-11 molecular sieve.
[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a method for preparing regular square plate-shaped small-grain SAPO-11 molecular sieve, characterized in that it comprises the following steps:
[0005] S1: Deionized water, orthophosphoric acid and an aluminum source are mixed according to a certain proportion, and stirred for 1-4 hours to obtain a mixed solution 1;
[0006] S2: adding the template and the acidic silica sol to the mixed solution 1, mixing, and stirring for 1-4 hours to obtain an initial gel;
[0007] S3: placing the initial gel into a crystallization kettle, performing primary crystallization and secondary crystallization to obtain a slurry crystallization product;
[0008] S4: washing, drying and calcining the slurry crystallization product in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve.
[0009] Preferably, the aluminum source in step S1 is pseudo-boehmite or aluminum isopropoxide.
[0010] Preferably, the molar ratio of deionized water, aluminum source and orthophosphoric acid in the mixed solution 1 in step S1 is 30-60:1:0.5-1.5.
[0011] Preferably, the template agent is one of di-n-propylamine and diisopropylamine or a mixture of the two. When the mixture is used, the molar ratio of di-n-propylamine to diisopropylamine is 0.1:0.9 to 0.9:0.1.
[0012] Preferably, the molar ratio of the acidic silica sol added in step S2 to the aluminum source in the mixed solution 1 is 0.1-0.5:1, and the molar ratio of the template added to the aluminum source in the mixed solution 1 is 0.5-1.5:1.
[0013] Preferably, in step S3, the primary crystallization temperature is 80-100° C., and the crystallization time is 1 h-5 h; the secondary crystallization temperature is 180° C.-200° C., and the crystallization time is 12 h-36 h.
[0014] Preferably, the calcination temperature in step S4 is 450° C. to 650° C., and the calcination time is 3 h to 6 h.
[0015] Compared with the prior art, the present invention can synthesize pure phase molecular sieves through suitable raw material ratios and suitable template agents and raw material ratios of template agents, and can make them present regular square flakes. At the same time, with low-temperature primary crystallization, the initial gel can quickly form more crystal nuclei, increase the concentration of crystal nuclei, consume most of the raw materials, thereby reducing the particle size of the crystals, and finally achieve the state of regular square flake-shaped small crystals. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 This is the XRD spectrum of the regular square plate-shaped small-grain SAPO-11 molecular sieve obtained in Example 1.
[0017] Figure 2 This is the SEM image of the regular square plate-shaped small-grain SAPO-11 molecular sieve obtained in Example 1.
[0018] Figure 3 This is the XRD spectrum of the regular square plate-shaped small-grain SAPO-11 molecular sieve obtained in Example 2.
[0019] Figure 4 This is the SEM image of the regular square plate-shaped small-grain SAPO-11 molecular sieve obtained in Example 2.
[0020] Figure 5 This is the XRD spectrum of the regular square plate-shaped small-grain SAPO-11 molecular sieve obtained in Example 3.
[0021] Figure 6This is the SEM image of the regular square plate-shaped small-grain SAPO-11 molecular sieve obtained in Example 3.
[0022] Figure 7 This is the XRD spectrum of the regular square plate-shaped small-grain SAPO-11 molecular sieve obtained in Example 4.
[0023] Figure 8 For Example 4 Figure 7 SEM image of regular square plate-shaped small grains of SAPO-11 molecular sieve. DETAILED DESCRIPTION
[0024] The present invention provides a method for preparing a regular square plate-shaped small-grain SAPO-11 molecular sieve, and the specific implementation method is as follows, comprising the following steps:
[0025] Embodiment 1:
[0026] S1: deionized water, orthophosphoric acid and pseudoboehmite were mixed in a ratio of 50:1:1, and stirred for 2 hours to obtain a mixed solution 1;
[0027] S2: adding a template agent dropwise to the mixed solution 1 in a molar ratio of 1:1 to the pseudo-boehmite in the mixed solution 1, wherein the template agent is a mixture of di-n-propylamine and diisopropylamine, and the molar ratio of di-n-propylamine to diisopropylamine is 0.5:0.5, and then adding acidic silica sol and stirring for 2 hours to obtain an initial gel, wherein the molar ratio of the acidic silica sol to the pseudo-boehmite in the mixed solution 1 is 0.3:1;
[0028] S3: The initial gel is placed in a crystallization kettle, and subjected to primary crystallization and secondary crystallization to obtain a slurry crystallization product, wherein the primary crystallization temperature is 90° C., the time is 3 h, and the secondary crystallization temperature is 190° C., the time is 24 h;
[0029] S4: The slurry crystallization product is washed, dried and calcined in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve. The drying temperature is 120° C., the calcination temperature is 550° C., and the calcination time is 4 h.
[0030] Embodiment 2:
[0031] S1: deionized water, orthophosphoric acid and pseudoboehmite were mixed in a ratio of 43:1:1, and stirred for 2 hours to obtain a mixed solution 1;
[0032] S2: adding a template agent dropwise to the mixed solution 1 in a molar ratio of 1:1 to the pseudo-boehmite in the mixed solution 1, wherein the template agent is a mixture of di-n-propylamine and diisopropylamine, and the molar ratio of di-n-propylamine to diisopropylamine is 0.9:0.1, and then adding acidic silica sol and stirring for 2 hours to obtain an initial gel, wherein the molar ratio of the acidic silica sol to the pseudo-boehmite in the mixed solution 1 is 0.2:1;
[0033] S3: The initial gel is placed in a crystallization kettle, and subjected to primary crystallization and secondary crystallization to obtain a slurry crystallization product, wherein the primary crystallization temperature is 100° C., the time is 3 h, and the secondary crystallization temperature is 190° C., the time is 24 h;
[0034] S4: The slurry crystallization product is washed, dried and calcined in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve. The drying temperature is 120° C., the calcination temperature is 550° C., and the calcination time is 4 h.
[0035] Embodiment three:
[0036] S1: deionized water, orthophosphoric acid and pseudoboehmite were mixed in a ratio of 50:1:1, and stirred for 2 hours to obtain a mixed solution 1;
[0037] S2: adding a template agent dropwise to the mixed solution 1 in a molar ratio of 1:1 to the pseudo-boehmite in the mixed solution 1, the template agent being a mixture of di-n-propylamine and diisopropylamine, the molar ratio of di-n-propylamine to diisopropylamine being 0.6:0.4, then adding acidic silica sol and stirring for 2 hours to obtain an initial gel, the molar ratio of the acidic silica sol to the pseudo-boehmite in the mixed solution 1 being 0.3:1;
[0038] S3: The initial gel is placed in a crystallization kettle, and subjected to primary crystallization and secondary crystallization to obtain a slurry crystallization product, wherein the primary crystallization temperature is 100° C., the time is 3 h, and the secondary crystallization temperature is 200° C., the time is 24 h;
[0039] S4: The slurry crystallization product is washed, dried and calcined in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve. The drying temperature is 120° C., the calcination temperature is 550° C., and the calcination time is 4 h.
[0040] Embodiment 4:
[0041] S1: deionized water, orthophosphoric acid and pseudoboehmite were mixed in a ratio of 50:1:1, and stirred for 2 hours to obtain a mixed solution 1;
[0042] S2: adding a template agent dropwise to the mixed solution 1 in a molar ratio of 1:1 to the pseudo-boehmite in the mixed solution 1, wherein the template agent is a mixture of di-n-propylamine and diisopropylamine, and the molar ratio of di-n-propylamine to diisopropylamine is 0.7:0.3, and then adding acidic silica sol and stirring for 2 hours to obtain an initial gel, wherein the molar ratio of the acidic silica sol to the pseudo-boehmite in the mixed solution 1 is 0.3:1;
[0043] S3: The initial gel is placed in a crystallization kettle, and subjected to primary crystallization and secondary crystallization to obtain a slurry crystallization product, wherein the primary crystallization temperature is 80° C., the time is 3 h, and the secondary crystallization temperature is 200° C., the time is 24 h;
[0044] S4: The slurry crystallization product is washed, dried and calcined in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve. The drying temperature is 120° C., the calcination temperature is 550° C., and the calcination time is 4 h.
[0045] Embodiment five:
[0046] S1: deionized water, orthophosphoric acid and pseudoboehmite were mixed in a ratio of 30:0.5:1, and stirred for 1 hour to obtain a mixed solution 1;
[0047] S2: adding a template agent dropwise to the mixed solution 1 at a molar ratio of 0.5:1 to the pseudo-boehmite in the mixed solution 1, wherein the template agent is di-n-propylamine, and then adding acidic silica sol, and stirring for 1 hour to obtain an initial gel, wherein the molar ratio of the acidic silica sol to the pseudo-boehmite in the mixed solution 1 is 0.1:1;
[0048] S3: The initial gel is placed in a crystallization kettle, and subjected to primary crystallization and secondary crystallization to obtain a slurry crystallization product, wherein the primary crystallization temperature is 80° C., the time is 5 h, and the secondary crystallization temperature is 180° C., the time is 30 h;
[0049] S4: The slurry crystallization product is washed, dried and calcined in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve. The drying temperature is 120° C., the calcination temperature is 450° C., and the calcination time is 6 h.
[0050] Embodiment six:
[0051] S1: deionized water, orthophosphoric acid and aluminum isopropoxide were mixed in a ratio of 60:1.5:1, and stirred for 4 hours to obtain a mixed solution 1;
[0052] S2: adding a template agent dropwise to the mixed solution 1 at a molar ratio of 1.5:1 to the aluminum isopropoxide in the mixed solution 1, wherein the template agent is diisopropylamine, and then adding acidic silica sol, and stirring for 4 hours to obtain an initial gel, wherein the molar ratio of the acidic silica sol to the aluminum isopropoxide in the mixed solution 1 is 0.5:1;
[0053] S3: The initial gel is placed in a crystallization kettle, and primary and secondary crystallizations are performed to obtain a slurry crystallization product, wherein the primary crystallization temperature is 100° C., the time is 1 h, and the secondary crystallization temperature is 200° C., the time is 12 h;
[0054] S4: The slurry crystallization product is washed, dried and calcined in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve. The drying temperature is 120° C., the calcination temperature is 650° C., and the calcination time is 3 h.
[0055] Embodiment seven:
[0056] S1: deionized water, orthophosphoric acid and aluminum isopropoxide were mixed in a ratio of 60:1.5:1, and stirred for 4 hours to obtain a mixed solution 1;
[0057] S2: adding a template agent dropwise to the mixed solution 1 in a molar ratio of 1:1 to the aluminum isopropoxide in the mixed solution 1, the template agent is a mixture of di-n-propylamine and diisopropylamine, the molar ratio of di-n-propylamine to diisopropylamine is 0.1:0.9, then adding acidic silica sol and stirring for 4 hours to obtain an initial gel, the molar ratio of the acidic silica sol to the aluminum isopropoxide in the mixed solution 1 is 0.5:1; S3: loading the initial gel into a crystallization kettle, performing primary crystallization and secondary crystallization to obtain a slurry crystallization product, the primary crystallization temperature is 100°C, the time is 1h, and the secondary crystallization temperature is 200°C, the time is 12h;
[0058] S4: The slurry crystallization product is washed, dried and calcined in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve. The drying temperature is 120° C., the calcination temperature is 650° C., and the calcination time is 3 h.
[0059] The reaction principle of the present invention is as follows: AlOOH [aluminum source] + H3PO4 [phosphorus source] + SiO2 [silicon source] + (CH3CH2CH2)2NH [di-n-propylamine-template] + CH3-NH-CH(CH3)2 [diisopropylamine-template] + H2O→xAl2O3·yP2O5 zSiO2·nH2O.
[0060] Depend on Figure 1 , 3 , 5, and 7 show that the products prepared in Examples 1, 2, 3, and 4 of the present invention are indeed SAPO-11 molecular sieves, and their diffraction peaks are the same as those of the target product. 2, 4, 6, and 8 show that the molecular sieves prepared in Examples 1, 2, 3, and 4 of the present invention have regular flake crystals.
[0061] The present invention is described by way of embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the protection scope of the present invention.
Claims
1. A method for preparing regular square flake-shaped small-grain SAPO-11 molecular sieve, characterized in that: The following steps are involved: S1: Deionized water, orthophosphoric acid and an aluminum source are mixed according to a certain proportion, and stirred for 1-4 hours to obtain a mixed solution 1; S2: adding the template and the acidic silica sol to the mixed solution 1, mixing, and stirring for 1-4 hours to obtain an initial gel; S3: placing the initial gel into a crystallization kettle, performing primary crystallization and secondary crystallization to obtain a slurry crystallization product; S4: washing, drying and calcining the slurry crystallization product in sequence to obtain regular flaky small-grain SAPO-11 molecular sieve.
2. The method for preparing a regular square plate-shaped small-grain SAPO-11 molecular sieve according to claim 1, characterized in that: The aluminum source in step S1 is pseudo-boehmite or aluminum isopropoxide.
3. The method for preparing a regular square plate-shaped small-grain SAPO-11 molecular sieve according to claim 1, characterized in that: The molar ratio of deionized water, aluminum source and orthophosphoric acid in the mixed solution 1 in step S1 is 30-60:1:0.5-1.
5.
4. The method for preparing a regular square plate-shaped small-grain SAPO-11 molecular sieve according to claim 1, characterized in that: The template agent is one of di-n-propylamine and diisopropylamine or a mixture of the two. When the mixture is used, the molar ratio of di-n-propylamine to diisopropylamine is 0.1:0.9 to 0.9:0.
1.
5. The method for preparing a regular square plate-shaped small-grain SAPO-11 molecular sieve according to claim 1, characterized in that: The molar ratio of the acidic silica sol added in step S2 to the aluminum source in the mixed solution 1 is 0.1-0.5:1, and the molar ratio of the template added to the aluminum source in the mixed solution 1 is 0.5-1.5:
1.
6. The method for preparing a regular square plate-shaped small-grain SAPO-11 molecular sieve according to claim 1, characterized in that: In step S3, the primary crystallization temperature is 80-100° C., and the crystallization time is 1 h-5 h; the secondary crystallization temperature is 180° C.-200° C., and the crystallization time is 12 h-36 h.
7. The method for preparing a regular square plate-shaped small-grain SAPO-11 molecular sieve according to claim 1, characterized in that: The calcination temperature in step S4 is 450° C. to 650° C., and the calcination time is 3 h to 6 h.