Aluminum-rich Beta molecular sieve and preparation method thereof

Abstract

The invention provides a method for preparing an aluminum-rich Beta zeolite molecular sieve through a one-time direct hydrothermal synthesis method under a sodium-containing condition, and the condition that impurities are easily generated when aluminum-rich Beta is synthesized under a traditional sodium-containing condition is overcome. The phosphorus-aluminum molecular sieve and the conventional aluminum source are used as the common aluminum source, so that the nucleation speed of crystal nucleus in the induction period in the crystallization process is increased, the nucleation activation energy of the molecular sieve is reduced, and the crystallization time is shortened. According to the invention, the phosphoaluminate molecular sieve is dissolved in the alkali source and the template agent to form the synthetic gel with the effects of accelerating crystallization and guiding. The adopted raw materials are easy to dissolve, and the operation steps are simple. The crystallization process is a one-step reaction, and the process is simple. According to the technical scheme, the impurity-free Beta zeolite molecular sieve with the silica-alumina ratio of 5.1 can be prepared, the solid product yield of the technical scheme is greater than 85%, and the method has the advantage of high yield and is suitable for large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic chemical synthesis, and specifically relates to a method for preparing aluminum-rich Beta molecular sieve. Background Art

[0002] Beta zeolite molecular sieve (hereinafter referred to as Beta zeolite) was first synthesized by Mobil Corporation using a hydrothermal method in 1967 (US3308069), and belongs to the BEA topology (BEA framework type, BEA is the structure code assigned by the International Molecular Sieve Association to molecular sieves with this structure, the BEA topology is as follows Figure 1 As shown, there are two intersecting twelve-membered ring channels: Figure 1 -a is a 0.66 nm×0.67 nm channel with

[100] and

[010] crystal orientations, Figure 1 -b is a 0.56 nm×0.56 nm pore with

[001] crystal orientation) and is a classic catalyst for the production of bulk and fine chemicals. In particular, the aluminum-rich (i.e., low silicon-aluminum ratio, silicon-aluminum ratio refers to the ratio of Si atoms to Al atoms in the molecular sieve) Beta molecular sieve has the advantages of dense acid sites, strong hydrophilicity and high ion exchange capacity. It is used in the alkylation of benzene, alkane cracking and hydroamination of aromatics, and selective reduction of NO after ion exchange with transition metals. x It exhibits excellent performance in other reactions.

[0003] In this context, people have been committed to developing new synthetic methods to obtain aluminum-rich Beta zeolite. Usually, Beta zeolite is prepared using tetraethylammonium hydroxide (TEAOH) as an organic structure directing agent (OSDA), and the silicon-aluminum ratio of the product is usually between 10 and 30. Theoretically, if each unit cell of Beta zeolite contains 6 TEAOH + The negative charges on the molecular sieve framework are all TEA + The corresponding silicon-aluminum ratio is 10. Vaudry et al. defined Beta zeolite with 6 aluminum atoms in the unit cell as stoichiometric zeolite, and its corresponding silicon-aluminum ratio is 9.65. Beta zeolite with a silicon-aluminum ratio lower than 9.65 is called aluminum-rich β zeolite (Zeolites, 1997, 19, 254). To incorporate more Al atoms into the framework requires more inorganic cations (such as Na + ) to balance the negative charge (AlO2 - ). However, this does not mean that simply adding more Na +The preparation of aluminum-rich Beta molecular sieve can be achieved. In fact, the synthesis of aluminum-rich Beta zeolite faces severe challenges because too much Na + The concentration will promote the formation of other dense zeolite phases such as GIS, ANA and MOR.

[0004] Qiang Zhang eliminated the formation of GIS phase by adding L-lysine, but the gel mixture needs to be stirred under an infrared lamp to evaporate excess water to achieve the required water ratio. Crystallization requires two-step reaction, first crystallizing at an initial temperature of 80°C for 48 hours, and then crystallizing at 140°C under static conditions for 48 hours, and finally obtaining pure Beta zeolite with a silicon-aluminum ratio of 6, but the two-step synthesis method is cumbersome. (Chem. Mater. 2020, 32, 2, 751-758). Patent CN111252782A first adds a small amount of aluminum source and all silicon sources and templates to react at 170°C for one day, and then adds most of the aluminum source, reacts at 170°C for two days, and finally obtains Beta zeolite with a silicon-aluminum ratio of 5. This method requires cooling, adding materials, and secondary crystallization after one day of high-temperature crystallization, and the synthesis is more complicated. Ramesh B. Borade prepared Beta with a silicon-aluminum ratio of 5.2 by reducing the amount of water (H2O / Si=5.4) and TEAOH (OSDA / SiO2=0.17), first preparing dry powder silica gel recrystallization, where the amount of liquid is just enough to wet the solid particles (fumed silica), and the low water content makes it difficult to mix the synthetic raw materials evenly, and it is difficult to use in large-scale production, and this method is prone to produce impurities such as hydrocalcium zeolite and analcime. (Microporous Mater. 5.1996, 289-297). Patent CN117509666A, under the conditions of NaOH as alkali source and TEAOH as template, after 10 wt% seed was added after dynamic reaction at 100-140℃ for 24 hours, and then dynamic secondary reaction at 140℃ for 96 hours, obtained Beta zeolite with a silicon-aluminum ratio of 3.6. This method requires two steps of high-temperature dynamic reaction, the synthesis is cumbersome, and the Beta molecular sieve needs to be added as a seed guide, which increases the synthesis cost. Patent CN118145663A, under the condition of adding potassium chloride, first dynamically aged at 50℃ for 12 hours by X molecular sieve crystallization, and then dynamically reacted at 150℃ for 72 hours to obtain Beta molecular sieve with a silicon-aluminum ratio of 5. The use of X molecular sieve is low in cost, but the two-step crystallization process is cumbersome. Patent WO97 / 33830 first used F-containing - and TEA +Under near-neutral conditions, ethyl silicate and aluminum powder were used as raw materials, and tetraethylammonium hydroxide was used as a template to synthesize pure phase Beta zeolite with a minimum silicon-aluminum ratio of 7.2, but the crystallization time was as long as 62 days. Patent CN101096274B, through high-temperature roasted silicon-aluminum co-gel as the silicon-aluminum source, crystallized at 170°C for 12 days to synthesize Beta zeolite with a silicon-aluminum ratio of 4.8, but in addition to the template agent tetraethylammonium hydroxide, it also requires the combined action of fluorides such as ammonium fluoride and hydrofluoric acid, which is not safe and environmentally friendly, and the crystallization time is long. Summary of the invention

[0005] As mentioned above, the existing synthesis technology for preparing aluminum-rich Beta molecular sieves has the disadvantages of harsh synthesis conditions, complex operation, and multi-step reactions. Aluminum-rich Beta zeolite is an important catalytic material because of its unique catalytic properties, so it is necessary to develop a more advanced method for synthesizing aluminum-rich Beta molecular sieves.

[0006] The purpose of the present invention is to prepare pure phase Beta zeolite by hydrothermal crystallization under sodium-containing conditions, using tetraethylammonium hydroxide as a template agent and partially replacing the conventional aluminum source with a phosphorus aluminum molecular sieve, wherein the silicon-aluminum ratio of the obtained product is as low as 5.1 and the solid product yield is greater than 85%. In order to achieve the above purpose, the present invention provides the following technical solutions: A method for preparing aluminum-rich Beta molecular sieve, the preparation steps are: S1, tetraethylammonium hydroxide solution, water and alkali source are mixed evenly, aluminophosphate molecular sieve is added and mixed evenly, and then a silicon source is added and heated and stirred to obtain a synthetic gel; The tetraethylammonium hydroxide, alkali source, water, aluminophosphate molecular sieve, and silicon source are mixed in a molar ratio of TEAOH: OH - :H2O:Al:Si is 0.5:0.15:16:(0.0625~0.125):1 for feeding; the OH - Only the OH contained in the alkali source - ; S2, subjecting the synthesized gel obtained in S1 to hydrothermal crystallization to obtain the final product; or, S1, tetraethylammonium hydroxide solution, water and alkali source are mixed evenly, and conventional aluminum source is added and mixed evenly; The tetraethylammonium hydroxide, alkali source and water are prepared according to a molar ratio of TEAOH: OH - : H2O is 0.5: 0.15: 16 for feeding; the OH - Only the OH contained in the alkali source - ; S2, adding aluminophosphate molecular sieve to the mixture obtained in S1 and mixing evenly, and then adding silicon source and heating and stirring to obtain synthetic gel; The molar ratio of the total amount of the conventional aluminum source in S1 and the aluminophosphate molecular sieve in S2 to the amount of TEAOH in S1 is Al: TEAOH = (0.0625~0.125): 0.5; wherein the molar ratio of the amount of the conventional aluminum source in S1 to the amount of the aluminophosphate molecular sieve in S2 is (1:3)~(3:1); The silicon source is fed at a molar ratio of Si:TEAOH of 1:0.5; S3, subjecting the synthesized gel obtained in S2 to hydrothermal crystallization to obtain a final product.

[0007] Preferably, the conventional aluminum source is selected from one or more of aluminum oxide, sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum sec-butoxide, aluminum chloride, pseudo-boehmite or aluminum isopropoxide.

[0008] Preferably, the aluminophosphate molecular sieve is selected from one or more molecular sieves having AFI, SFO, AEI, AEL, SFO, AEI, AFO, AFT, AST, AVE, EZT, OSI, PON, POR, PSI, SAF, and VFI topological structures.

[0009] Preferably, the aluminophosphate molecular sieve is selected from AlPO-5 aluminophosphate molecular sieve, SSZ-51 aluminophosphate molecular sieve, and AlPO-18 aluminophosphate molecular sieve.

[0010] Preferably, the alkali source is an alkali metal hydroxide, and the alkali metal hydroxide is selected from one or more of sodium hydroxide, potassium hydroxide or lithium hydroxide.

[0011] Preferably, the silicon source is selected from one or more of silica sol, tetraethyl orthosilicate or silicon dioxide.

[0012] Preferably, the heating and stirring treatment is a stirring treatment at 50-80° C. for 5-12 hours.

[0013] Preferably, the hydrothermal crystallization treatment is carried out under static conditions or dynamic stirring conditions at 120-150° C. for 2-7 days.

[0014] The optimal technical solution is: S1, tetraethylammonium hydroxide solution, water and an alkali source are mixed evenly, AlPO-5 type aluminophosphate molecular sieve is added and mixed evenly, and then silicon dioxide is added and heated and stirred to obtain a synthetic gel; the alkali source is selected from one of sodium hydroxide, potassium hydroxide or lithium hydroxide; The tetraethylammonium hydroxide, alkali source, water, AlPO-5 type aluminophosphate molecular sieve, and silicon dioxide are mixed according to a molar ratio of TEAOH: OH - : H2O: Al: Si is 0.5: 0.15: 16: 0.125: 1 for feeding; the OH - Only the OH contained in the alkali source - ; S2, subjecting the synthesized gel obtained in S1 to hydrothermal crystallization to obtain the final product; or, S1, mixing tetraethylammonium hydroxide solution, water and an alkali source uniformly, and adding aluminum hydroxide to mix uniformly; The tetraethylammonium hydroxide, alkali source and water are prepared according to a molar ratio of TEAOH: OH - : H2O is 0.5: 0.15: 16 for feeding; the OH - Only the OH contained in the alkali source - ; The alkali source is selected from one of sodium hydroxide, potassium hydroxide or lithium hydroxide; The conventional aluminum source is selected from aluminum hydroxide; S2, adding AlPO-5 type aluminophosphate molecular sieve to the mixture obtained in S1 and mixing evenly, and then adding silicon dioxide and heating and stirring to obtain a synthetic gel; The molar ratio of the total amount of aluminum hydroxide in S1 and the AlPO-5 type aluminophosphate molecular sieve in S2 to the amount of TEAOH in S1 is Al:TEAOH = 0.125:0.5; wherein the molar ratio of the amount of aluminum hydroxide in S1 to the amount of AlPO-5 type aluminophosphate molecular sieve in S2 is (1:3) or (1:1) or (3:1); The silicon dioxide is added according to a molar ratio of Si:TEAOH of 1:0.5.

[0015] The present invention also provides an aluminum-rich Beta molecular sieve, wherein the aluminum-rich Beta molecular sieve is prepared by mixing a silicon source, an aluminum source, a template, an alkali source, and water in a molar ratio of 1: (0.0625-0.125): (0.2-0.7): (0.1-0.3): (10-20) through a direct hydrothermal synthesis method; further, the optimal molar ratio is 1: 0.125: 0.5: 0.15: 10-26; The template agent is tetraethylammonium hydroxide; the alkali source is an alkali metal hydroxide, and the alkali metal hydroxide is selected from one or more of sodium hydroxide, potassium hydroxide or lithium hydroxide; the silicon source is selected from one or more of silica sol, tetraethyl orthosilicate or silicon dioxide; The aluminum source is a mixed aluminum source formed by combining aluminophosphate molecular sieve and a conventional aluminum source, wherein the ratio of aluminophosphate molecular sieve to the aluminum source is any value in the range of (0.01 to 0.99); or the aluminum source is completely selected from aluminophosphate molecular sieve; or the aluminum source is completely selected from conventional aluminum sources; The aluminophosphate molecular sieve is selected from one or more of the molecular sieves having AFI, SFO, AEI, AEL, SFO, AEI, AFO, AFT, AST, AVE, EZT, OSI, PON, POR, PSI, SAF, and VFI topological structures; The conventional aluminum source is selected from one or more of aluminum oxide, sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum sec-butoxide, aluminum chloride, pseudo-boehmite or aluminum isopropoxide.

[0016] Beneficial Effects The present invention provides a method for preparing aluminum-rich Beta zeolite molecular sieve by a one-time direct hydrothermal synthesis method under sodium-containing conditions, which overcomes the problem that impurities are easily generated when synthesizing aluminum-rich Beta under traditional sodium-containing conditions. The present invention uses a phosphate aluminum molecular sieve and a conventional aluminum source as a common aluminum source, thereby increasing the nucleation rate of the crystal nucleus during the induction period of the crystallization process, reducing the molecular sieve nucleation activation energy, and shortening the crystallization time. The present invention dissolves the phosphate aluminate molecular sieve in an alkali source and a template agent to form a synthetic gel with accelerated crystallization and guiding effects. The raw materials used in the present invention are easy to dissolve and the operation steps are simple. The crystallization process of the present invention is a one-step reaction and the process is simple. The technical solution of the present invention can prepare a Beta zeolite molecular sieve free of impurities with a silicon-aluminum ratio of 5.1. The solid product yield of the technical solution is greater than 85%, which has the advantages of high yield and is suitable for scale-up production. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a BEA topological structure; 1-a is a projection view along the

[001] crystal direction; 1-b is a projection view along the

[100] crystal direction; Figure 2 The XRD diagrams are obtained by performing X-ray diffraction detection on the Beta zeolite molecular sieves prepared in Comparative Example 1 and Examples 1-4; Figure 3 The XRD diagrams are obtained by performing X-ray diffraction detection on the Beta zeolite molecular sieves prepared in Comparative Example 5 and Examples 5-8; Figure 4 The XRD diagram is obtained by performing X-ray diffraction detection on the Beta zeolite molecular sieve prepared in Examples 9-12; Figure 5 The XRD diagram is obtained by performing X-ray diffraction detection on the Beta zeolite molecular sieve prepared in Examples 13-18; Figure 6The XRD diagrams are obtained by performing X-ray diffraction detection on the Beta zeolite molecular sieves prepared in Comparative Examples 3-4 and Examples 19-24; Figure 7 This is the XRD diagram obtained by performing X-ray diffraction detection on the Beta zeolite molecular sieve prepared in Examples 25-28. DETAILED DESCRIPTION

[0018] Comparative Example 1 Step 1, according to Al: TEAOH: OH - (NaOH) : H2O = 0.0625: 0.5: 0.15: 16, firstly mix sodium hydroxide with deionized water and tetraethylammonium hydroxide solution, and then add a conventional aluminum source; the conventional aluminum source is selected from aluminum hydroxide; Step 2, stirring the mixture obtained in step 1 at 25° C., and then heating at 80° C. for 12 h; Step 3, after the mixture obtained in step 2 is cooled, a silicon source M5 is added according to a molar ratio of Si: Al = 1: 0.0625 to obtain a synthetic gel; in summary, the raw material ratio of the synthetic gel is Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.0625 : 0.5: 0.15 : 16; Step 4, stirring the synthetic gel obtained in step 3 at 25° C. for 15 minutes, and then placing it in a high-pressure reactor for static hydrothermal reaction at 140° C. for 6 days; Step 5, centrifuging and drying the product obtained in step 4 to obtain the product Beta zeolite molecular sieve.

[0019] Detection Comparative Example 1 The product of Comparative Example 1 was subjected to XRD detection, and its XRD data is shown in Table 1, which indicates that it is a classic conventional Beta molecular sieve.

[0020] Table 1

[0021] w: weak mw: medium-weak m: medium s: strong vs: very strong Example 1 Step 1: Mix the alkali source (NaOH) and deionized water at a molar ratio of NaOH: H2O of 0.15:16 to obtain an alkali solution, and then add TEAOH: OH -(NaOH) is 0.5: 0.15. Tetraethylammonium hydroxide (TEAOH) solution is added to the alkali solution and mixed evenly, and then a conventional aluminum source is added (in this embodiment, the aluminum source is added twice, namely, the conventional aluminum source is added in step 1, and the aluminophosphate molecular sieve is added in step 3. The molar ratio of the total amount of the aluminum source added twice to the amount of TEAOH is Al: TEAOH = 0.0625: 0.5; wherein the amount of the conventional aluminum source in step 1 (in terms of the molar amount of Al atoms) is 75% of the total amount of the aluminum source added twice, and the amount of the aluminophosphate molecular sieve in step 3 (in terms of the molar amount of Al atoms) is 25% of the total amount of the aluminum source added twice); the conventional aluminum source is aluminum hydroxide; Step 2, stirring the mixture obtained in step 1 at 25° C., and then heating at 80° C. for 12 h; Step 3, after the mixture obtained in step 2 is cooled, add aluminophosphate molecular sieve AlPO-5 (having an AFI topological structure); then add silicon dioxide at a molar ratio of Si: TEAOH of 1:0.5 to obtain a synthetic gel; the silicon dioxide in this embodiment is selected from M5 type fumed silica; in summary, the feed ratio of each raw material in the synthetic gel is Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.0625 : 0.5: 0.15 : 16; Step 4, stirring the synthetic gel obtained in step 3 at 25° C. for 15 minutes, and then placing it in a high-pressure reactor for static hydrothermal reaction at 140° C. for 5 days; Step 5, centrifuging and drying the product obtained in step 4 to obtain Beta zeolite molecular sieve.

[0022] Example 2 The same raw materials as in Example 1 were used, the amount of the conventional aluminum source in step 1 (in terms of the molar amount of Al atoms) was 50% of the total amount of the aluminum sources in two times, and the amount of the aluminophosphate molecular sieve in step 3 (in terms of the molar amount of Al atoms) was 50% of the total amount of the aluminum sources in two times); at the same time, the static hydrothermal reaction time was adjusted to 4 days, and the others were consistent with Example 1. The obtained product was Beta molecular sieve.

[0023] Example 3 The same raw materials as in Example 1 were used, the amount of the conventional aluminum source in step 1 (in terms of the molar amount of Al atoms) was 25% of the total amount of the aluminum sources in two times, and the amount of the aluminophosphate molecular sieve in step 3 (in terms of the molar amount of Al atoms) was 75% of the total amount of the aluminum sources in two times); at the same time, the static hydrothermal reaction time was adjusted to 3 days, and the others were consistent with Example 1. The obtained product was Beta molecular sieve.

[0024] Example 4 The same raw materials as in Comparative Example 1 were used, and the conventional aluminum source was replaced with aluminophosphate molecular sieve AlPO-5; and step 2 did not require heating at 80° C. overnight, and the static hydrothermal reaction time was adjusted to 2 days. The rest was consistent with Comparative Example 1.

[0025] Detection Example 1 The product obtained in Example 4 was subjected to XRD detection, and its XRD data are shown in Table 2 Table 2

[0026] Comparative Example 2 Only the alkali source was replaced with KOH, and the other raw materials were the same as those in Comparative Example 1, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (KOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, the static hydrothermal crystallization time was changed to 7 days and the other conditions were the same as those in Comparative Example 1. The obtained product was centrifuged and dried to obtain a Beta molecular sieve, and it was found that the product contained an impurity phase.

[0027] Detection Comparative Example 2 The product of Comparative Example 2 was subjected to XRD detection, and its XRD data are shown in Table 3. A strong diffraction peak that does not belong to Beta molecular sieve appears. When the silica-aluminum ratio of the feed gel is 10 and all aluminum sources are conventional aluminum sources, the product is a mixed phase of Beta and GIS.

[0028]

[0029] Table 3 Example 5 Only the alkali source was replaced by KOH, the silicon source was replaced by silicon dioxide, and the other raw materials were the same as those in Example 1, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (KOH) : H2O = 1 : 0.1 : 0.5:0.15 : 16, the static hydrothermal crystallization time was changed to 6 days, and the rest was consistent with Example 1 to obtain a product Beta molecular sieve, and it was measured that the product contained an impurity phase.

[0030] Example 6 Only the alkali source was replaced by KOH, the silicon source was replaced by silicon dioxide, and the other raw materials were the same as those in Example 2, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH -(KOH) : H2O = 1 : 0.1 : 0.5:0.15 : 16, the static hydrothermal crystallization time was changed to 5 days, and the rest was consistent with Example 2 to obtain a product Beta molecular sieve, and it was measured that the product contained an impurity phase.

[0031] Example 7 Only the alkali source was replaced by LiOH, the silicon source was replaced by silicon dioxide, and the other raw materials were the same as those in Example 3, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (LiOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, the static hydrothermal crystallization time was changed to 4 days, and the other conditions were the same as those in Example 3 to obtain the product Beta molecular sieve, and it was measured that the product did not contain impurity phase. That is, when the silicon-aluminum ratio of the feed was 10 and the aluminum atoms provided by the phosphorus-aluminum molecular sieve AlPO-5 accounted for 75%, the obtained product was free of impurities.

[0032] Example 8 Only the alkali source was replaced by LiOH, the silicon source was replaced by silica sol, and the other raw materials were the same as those in Example 4, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (LiOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, the static hydrothermal crystallization time was changed to 3 days, and the rest was consistent with Example 4 to obtain a product Beta molecular sieve, and it was measured that the product did not contain impurity phase.

[0033] Example 9 Only the conventional aluminum source is replaced by aluminum oxide, the silicon source is replaced by silica sol, the aluminophosphate molecular sieve in the raw material is adjusted to SSZ-51 (having an SFO topological structure), and the remaining raw materials are the same as those in Example 1, and the feed molar composition is adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 7 days, and the rest are consistent with Example 1. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product contains an impurity phase.

[0034] Example 10 Only the conventional aluminum source is replaced by aluminum oxide, the silicon source is replaced by silica sol, the aluminophosphate molecular sieve in the raw material is adjusted to SSZ-51 (having an SFO topological structure), and the remaining raw materials are the same as those in Example 2, and the feed molar composition is adjusted to Si: Al: TEAOH: OH -(NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 5 days, and the rest are consistent with Example 2. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product contains an impurity phase.

[0035] Embodiment 11 Only the conventional aluminum source is replaced by aluminum oxide, the silicon source is replaced by silica sol, the aluminophosphate molecular sieve in the raw material is adjusted to SSZ-51 (having an SFO topological structure), and the other raw materials are the same as those in Example 3, and the feed molar composition is adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 4 days, the rest is consistent with Example 3. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product does not contain impurity phase.

[0036] Example 12 Only the conventional aluminum source was replaced with sodium aluminate, the silicon source was replaced with tetraethyl orthosilicate, the aluminophosphate molecular sieve in the raw material was adjusted to SSZ-51 (having an SFO topological structure), and the remaining raw materials were the same as those in Example 4, and the feed molar composition was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 3 days, the rest is consistent with Example 4. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product does not contain impurity phase.

[0037] Embodiment 13 Only the conventional aluminum source is replaced by sodium aluminate, the silicon source is replaced by tetraethyl orthosilicate, the aluminophosphate molecular sieve in the raw material is adjusted to AlPO-18 (having an AEI topological structure), and the remaining raw materials are the same as those in Example 1, and the feed molar composition is adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 7 days, and the rest are consistent with Example 1. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product contains an impurity phase.

[0038] Embodiment 14 Only the conventional aluminum source is replaced by sodium aluminate, the silicon source is replaced by tetraethyl orthosilicate, the aluminophosphate molecular sieve in the raw material is adjusted to AlPO-18 (having an AEI topological structure), and the remaining raw materials are the same as those in Example 2, and the feed molar composition is adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 5 days, and the rest are consistent with Example 2. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product contains an impurity phase.

[0039] Embodiment 15 Only the conventional aluminum source was replaced by aluminum sulfate, the silicon source was replaced by tetraethyl orthosilicate, the aluminophosphate molecular sieve in the raw material was adjusted to AlPO-18 (having an AEI topological structure), and the remaining raw materials were the same as those in Example 3, and the feed molar composition was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 4 days, the rest is consistent with Example 3. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product does not contain impurity phase.

[0040] Example 16 Only the conventional aluminum source was replaced with aluminum sulfate, the aluminophosphate molecular sieve in the raw material was adjusted to AlPO-18 (having an AEI topological structure), and the remaining raw materials were the same as those in Example 4, and the feed molar composition was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, crystallization time 3 days, the rest is consistent with Example 4. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product does not contain impurity phase.

[0041] Embodiment 17 Only the conventional aluminum source was replaced by aluminum nitrate, the silicon source was replaced by tetraethyl orthosilicate, and the other raw materials were the same as those in Example 1, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, static crystallization was changed to dynamic crystallization, the crystallization time was 6 days, and the rest was consistent with Example 1. The obtained product was centrifuged and dried to obtain a product Beta molecular sieve, and it was measured that the product contained an impurity phase.

[0042] Embodiment 18 Only the conventional aluminum source was replaced with aluminum nitrate, and the other raw materials were the same as those in Example 4, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.1 : 0.5 : 0.15 : 16, static crystallization was changed to dynamic crystallization, the crystallization time was 3 days, and the rest was consistent with Example 4. The obtained product was centrifuged and dried to obtain a product Beta molecular sieve, and it was measured that the product did not contain impurity phase.

[0043] Comparative Example 3 The same raw materials as in Comparative Example 1 were used, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the static hydrothermal aging time is changed to 7 days, and the other conditions are the same as those in Comparative Example 1. The obtained product is centrifuged and dried to obtain the product Beta molecular sieve, and it is measured that the product contains impurity phase. When the feed silicon-aluminum ratio is 8, pure phase Beta cannot be synthesized if all aluminum sources are conventional aluminum sources.

[0044] Comparative Example 4 Only the conventional aluminum source was replaced by aluminum isopropoxide, and the other raw materials were the same as those in Comparative Example 1, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the static hydrothermal aging time is changed to 6 days, and the rest is consistent with Comparative Example 1. The obtained product is centrifuged and dried to obtain an amorphous product.

[0045] Embodiment 19 Only the conventional aluminum source was replaced by aluminum isopropoxide, and the other raw materials were the same as those in Example 1, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the hydrothermal crystallization time was adjusted to 7 days, and the rest was consistent with Example 1. The obtained product was centrifuged and dried to obtain a product Beta molecular sieve, and it was measured that the product contained an impurity phase.

[0046] Embodiment 20 Only the conventional aluminum source was replaced by aluminum isopropoxide, and the other raw materials were the same as those in Example 2, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH -(NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the hydrothermal crystallization time was adjusted to 4 days, and the rest was consistent with Example 2. The obtained product Beta molecular sieve was measured to contain no impurity phase.

[0047] Embodiment 21 Only the conventional aluminum source was replaced by pseudo-boehmite, and the other raw materials were the same as those in Example 2, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the hydrothermal crystallization time was adjusted to 5 days, and the rest was consistent with Example 2. The obtained product Beta molecular sieve was measured to contain no impurity phase.

[0048] Embodiment 22 Only the conventional aluminum source was replaced by pseudo-boehmite, and the other raw materials were the same as those in Example 3, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the hydrothermal crystallization time was adjusted to 5 days, and the rest was consistent with Example 3. The obtained product Beta molecular sieve was measured to contain no impurity phase.

[0049] Embodiment 23 The same raw materials as in Example 4 were used, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the hydrothermal crystallization time was adjusted to 3 days, and the rest was consistent with Example 4. The obtained product Beta molecular sieve was measured to contain no impurity phase.

[0050] Embodiment 24 The same raw materials as in Example 4 were used, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, the hydrothermal crystallization time was adjusted to 4 days, and the rest was consistent with Example 4. The obtained product Beta molecular sieve was free of impurities Embodiment 25 Only the conventional aluminum source was replaced with aluminum chloride, the aluminophosphate molecular sieve in the raw material was adjusted to SSZ-51 (having an SFO topological structure), and the remaining raw materials were the same as those in Example 1, and the feed molar composition was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, crystallization time 7 days, the rest is consistent with Example 1. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product contains an impurity phase.

[0051] Embodiment 26 Only the aluminophosphate molecular sieve was adjusted to SSZ-51 (having an SFO topological structure), and the other raw materials were the same as those in Example 4, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, crystallization time 4 days, the rest is consistent with Example 4. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product does not contain impurity phase.

[0052] Embodiment 27 Only the conventional aluminum source was replaced with aluminum sec-butoxide, the aluminophosphate molecular sieve in the raw material was adjusted to AlPO-18 (having an AEI topological structure), and the remaining raw materials were the same as those in Example 1, and the feed molar composition was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, crystallization time 6 days, the rest is consistent with Example 1. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product contains an impurity phase.

[0053] Embodiment 28 Only the aluminophosphate molecular sieve was adjusted to AlPO-18 (having an AEI topological structure), and the other raw materials were the same as those in Example 4, and the molar composition of the feed was adjusted to Si: Al: TEAOH: OH - (NaOH) : H2O = 1 : 0.125 : 0.5 : 0.15 : 16, crystallization time 3 days, the rest is consistent with Example 4. The obtained product is centrifuged and dried to obtain a product Beta molecular sieve, and it is measured that the product does not contain impurity phase.

[0054] Detection Example 3 The products obtained from Comparative Examples 1 to 4 and Examples 1 to 28 were subjected to X-ray fluorescence spectrometry (XRF) analysis to calculate the silicon-aluminum ratio and the yield of the impurity-free sample. The XRF data and yield are shown in Table 4. Table 4

Claims

1. A method for preparing aluminum-rich Beta molecular sieve, characterized in that: The preparation steps are: S1, tetraethylammonium hydroxide solution, water and alkali source are mixed evenly, aluminophosphate molecular sieve is added and mixed evenly, and then a silicon source is added and heated and stirred to obtain a synthetic gel; The tetraethylammonium hydroxide, alkali source, water, aluminophosphate molecular sieve, and silicon source are mixed in a molar ratio of TEAOH: OH - : H2O: Al: Si is 0.5: 0.15: 16: (0.0625~0.125): 1 for feeding; the OH - Only the OH contained in the alkali source - ; S2, subjecting the synthesized gel obtained in S1 to hydrothermal crystallization to obtain the final product; or, S1, tetraethylammonium hydroxide solution, water and alkali source are mixed evenly, and conventional aluminum source is added and mixed evenly; The tetraethylammonium hydroxide, alkali source and water are prepared according to a molar ratio of TEAOH: OH - : H2O is 0.5: 0.15: 16 for feeding; the OH - Only the OH contained in the alkali source - ; S2, adding aluminophosphate molecular sieve to the mixture obtained in S1 and mixing evenly, and then adding silicon source and heating and stirring to obtain synthetic gel; The molar ratio of the total amount of the conventional aluminum source in S1 and the aluminophosphate molecular sieve in S2 to the amount of TEAOH in S1 is Al: TEAOH = (0.0625~0.125): 0.5; wherein the molar ratio of the amount of the conventional aluminum source in S1 to the amount of the aluminophosphate molecular sieve in S2 is (1:3)~(3:1); The silicon source is fed at a molar ratio of Si:TEAOH of 1:0.5; S3, subjecting the synthesized gel obtained in S2 to hydrothermal crystallization to obtain a final product.

2. The preparation method according to claim 1, characterized in that The conventional aluminum source is selected from one or more of aluminum oxide, sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum sec-butoxide, aluminum chloride, pseudo-boehmite or aluminum isopropoxide.

3. The preparation method according to claim 1, characterized in that The aluminophosphate molecular sieve is selected from one or more molecular sieves having AFI, SFO, AEI, AEL, SFO, AEI, AFO, AFT, AST, AVE, EZT, OSI, PON, POR, PSI, SAF, and VFI topological structures.

4. The preparation method according to claim 1, characterized in that The aluminophosphate molecular sieve is selected from AlPO-5 aluminophosphate molecular sieve, SSZ-51 aluminophosphate molecular sieve, and AlPO-18 aluminophosphate molecular sieve.

5. The preparation method according to claim 1, characterized in that The alkali source is an alkali metal hydroxide, and the alkali metal hydroxide is selected from one or more of sodium hydroxide, potassium hydroxide or lithium hydroxide.

6. The preparation method according to claim 1, characterized in that The silicon source is selected from one or more of silica sol, tetraethyl orthosilicate or silicon dioxide.

7. The preparation method according to claim 1, characterized in that The heating and stirring treatment is carried out under the condition of 50-80° C. and stirring for 5-12 hours.

8. The preparation method according to claim 1, characterized in that The hydrothermal crystallization treatment is carried out under static conditions or dynamic stirring conditions at 120-150° C. for 2-7 days.

9. The preparation method according to claim 1, characterized in that S1, tetraethylammonium hydroxide solution, water and an alkali source are mixed evenly, AlPO-5 type aluminophosphate molecular sieve is added and mixed evenly, and then silicon dioxide is added and heated and stirred to obtain a synthetic gel; the alkali source is selected from one of sodium hydroxide, potassium hydroxide or lithium hydroxide; The tetraethylammonium hydroxide, alkali source, water, AlPO-5 type aluminophosphate molecular sieve, and silicon dioxide are prepared according to a molar ratio of TEAOH: OH - : H2O: Al: Si is 0.5: 0.15: 16: 0.125: 1 for feeding; the OH - Only the OH contained in the alkali source - ; S2, subjecting the synthesized gel obtained in S1 to hydrothermal crystallization to obtain the final product; or, S1, mixing tetraethylammonium hydroxide solution, water and an alkali source uniformly, and adding aluminum hydroxide to mix uniformly; The tetraethylammonium hydroxide, alkali source and water are prepared according to a molar ratio of TEAOH: OH - : H2O is 0.5: 0.15: 16 for feeding; the OH - Only the OH contained in the alkali source - ; The alkali source is selected from one of sodium hydroxide, potassium hydroxide or lithium hydroxide; The conventional aluminum source is selected from aluminum hydroxide; S2, adding AlPO-5 type aluminophosphate molecular sieve to the mixture obtained in S1 and mixing evenly, and then adding silicon dioxide and heating and stirring to obtain a synthetic gel; The molar ratio of the total amount of aluminum hydroxide in S1 and the AlPO-5 type aluminophosphate molecular sieve in S2 to the amount of TEAOH in S1 is Al:TEAOH = 0.125:0.5; wherein the molar ratio of the amount of aluminum hydroxide in S1 to the amount of AlPO-5 type aluminophosphate molecular sieve in S2 is (1:3) or (1:1) or (3:1); The silicon dioxide is added according to a molar ratio of Si:TEAOH of 1:0.

5.

10. An aluminum-rich Beta molecular sieve, characterized in that: The Beta molecular sieve is prepared by mixing a silicon source, an aluminum source, a template, an alkali source, and water in a molar ratio of 1: (0.0625-0.125): (0.2-0.7): (0.1-0.3): (10-20) through a direct hydrothermal synthesis method; The template agent is tetraethylammonium hydroxide; the alkali source is an alkali metal hydroxide, and the alkali metal hydroxide is selected from one or more of sodium hydroxide, potassium hydroxide or lithium hydroxide; the silicon source is selected from one or more of silica sol, tetraethyl orthosilicate or silicon dioxide; The aluminum source is a mixed aluminum source formed by combining aluminophosphate molecular sieve and a conventional aluminum source, wherein the ratio of aluminophosphate molecular sieve to the aluminum source is any value in the range of (0.01-0.99); Or the aluminum source is completely selected from aluminophosphate molecular sieves; Or the aluminum source is completely selected from conventional aluminum sources; The aluminophosphate molecular sieve is selected from one or more of the molecular sieves having AFI, SFO, AEI, AEL, SFO, AEI, AFO, AFT, AST, AVE, EZT, OSI, PON, POR, PSI, SAF, and VFI topological structures; The conventional aluminum source is selected from one or more of aluminum oxide, sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, aluminum chloride, aluminum sec-butoxide, aluminum chloride, pseudo-boehmite or aluminum isopropoxide.

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