WO2026001519A1 - Aluminosilicate molecular sieves having ultra-large pore structures, synthesis method therefor, and use thereof - Google Patents

Abstract

Provided are two aluminosilicate molecular sieves having ultra-large pore structures, designated NJU120-1 and NJU120-2. The schematic chemical composition of the as-synthesized state of the molecular sieves is: rROH:a(OH- or F-):xAl ₂O ₃:SiO ₂:wH ₂O, and the schematic chemical composition after calcination is: (HAlO ₂) _x·SiO ₂. After calcination of NJU120-1, the framework structure composed of a T(Si, Al)O ₄ tetrahedron thereof has a 22 × 10 × 10-membered cyclic three-dimensional pore channel system. After calcination of NJU120-2, the framework structure composed of a T(Si, Al)O ₄ tetrahedron thereof has a 22 × 12 × 10-membered cyclic three-dimensional pore channel system. The molecular sieves are reasonably designed, are germanium-free, high-silicon or pure-silicon, fully connected ultra-large pore molecular sieve materials, and have very important practical application value in areas including catalysis, adsorptive separation, etc.

Description

Aluminosilicate molecular sieves with ultra-large pore structures, their synthesis methods and applications Technical Field

This invention relates to the field of zeolite molecular sieve technology, and more particularly to aluminosilicate molecular sieves with ultra-large pore structures, as well as their synthesis methods and uses.

Background Technology

Zeolite molecular sieves are a class of inorganic crystalline materials with regular microporous/mesoporous channel structures. They are based on _TO₄ tetrahedra (where T atoms can be silicon, aluminum, phosphorus, germanium, gallium, etc.) as basic structural units, connected by oxygen atoms to form a regular, ordered three-dimensional framework structure. Different connection methods between _{TO₄ tetrahedra} can construct various zeolite materials with different topological configurations. Zeolite molecular sieves generally have one-dimensional or multi-dimensional channels, with pore sizes ranging from octagonal rings (approximately 0.4 nm in diameter) to thirtieth-membered rings (approximately 1.93 nm in diameter). The structural units of the molecular sieve determine its long-range ordered porous structure, while also endowing it with excellent performance in catalysis and adsorption separation: large specific surface area and uniform pore size distribution; pore size and acid-base properties can be tuned through simple ion exchange; and the silicon-to-aluminum ratio of the molecular sieve can be adjusted within a certain range by modifying the ratio of the synthesis raw materials, thereby changing the surface polarity and electric field to achieve optimal catalytic and adsorption separation effects. Hydrothermal synthesis is the most common method for synthesizing molecular sieves. Typically, it involves mixing a silicon source (such as silica sol), an aluminum source (such as inorganic aluminum salts), an alkali, and water in appropriate proportions, and heating the mixture in a hydrothermal reactor for a certain time to synthesize molecular sieve crystals. Sometimes, organic amines are added as template agents to guide the structure, but these template agents are mostly inexpensive. The excellent thermal/hydrothermal stability and low synthesis cost of molecular sieves make them promising catalytic and adsorption separation materials, meeting the needs of industrial applications. A molecular sieve with a specific structure needs further differentiation using X-ray powder diffraction (XRD), because different crystal structures result in different pore structures, leading to completely different diffraction patterns in XRD tests. Existing molecular sieves, such as type A molecular sieve (US2882243), type Y molecular sieve (US3130007), ZSM-11 molecular sieve (US3709979), ZSM-23 molecular sieve (US4076843), and ZSM-35 molecular sieve (US4016245), all have their own characteristic powder X-ray diffraction (XRD) patterns.

Molecular sieve materials can be classified into microporous, mesoporous, macroporous, and macroporous molecular sieves based on the number of rings in their pores, corresponding to window ring numbers of less than 8 members, less than 10 members, less than 12 members, and greater than 12 members, respectively. However, the crystallization of macroporous zeolite molecular sieves with more than 12 members is very difficult, usually requiring special organic structure-directing agents and the participation of germanium, such as the 30-membered ring ITQ-37 [J.Sun et al., Nature, 2009, 458, 1154-1157], the 28-membered ring ITQ-43 [J.Jiang et al., Science, 2011, 333, 1131-1134], and the 18-membered ring NUD-1 molecular sieve (CN104370296A). Firstly, germanium is expensive, and secondly, the hydrothermal stability of the molecular sieve framework is poor when germanium is present, limiting the application range of germanium-containing macroporous zeolite molecular sieves.

Due to their good stability and the ease of manipulating the chemical microenvironment within their pores, aluminosilicate zeolite molecular sieves are widely used in petrochemicals, fine chemicals, energy conversion and storage, and biomedicine. However, the number of aluminosilicate molecular sieve materials with ultra-large pores and stable framework structures is limited. Examples include the 16-membered ring channel ZEO-1 molecular sieve (Lin et al., Science, 2021, 374, 1605-1608.), the 16-membered ring channel ZEO-3 molecular sieve (Li et al., Science, 2023, 379, 283-287.), and the recently reported 20-membered ring channel ZEO-5 molecular sieve (Gao et al., Nature, 2024, 628, 99–103.). Both ZEO-3 and ZEO-5 have a pure silicon framework and are not obtained through direct hydrothermal synthesis but rather through post-processing. Ultra-large pore aluminosilicate molecular sieves have significant practical value for handling chemical processes involving macromolecules.

Summary of the Invention

This invention proposes an aluminosilicate molecular sieve with an ultra-large pore structure, as well as its synthesis method and applications. It is a novel, germanium-free, high-silicon or pure-silicon ultra-large pore molecular sieve material, which not only has very important practical application value in catalysis, adsorption separation and other fields, but also has very important theoretical significance for enriching the molecular sieve structure family.

To achieve the above objectives, the present invention adopts the following technical solution:

An aluminosilicate molecular sieve with an ultra-large pore structure has the following schematic chemical composition in its synthesized state: rROH: _a (OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O , and the following schematic chemical composition after calcination: ( _HAlO₂ ) _x · _SiO₂ .

Preferably, the molecular sieve is NJU120-1, and after calcination, the NJU120-1 has a three-dimensional channel system of 22×10×10-membered rings in its framework structure composed of T(Si,Al) _O4 tetrahedra.

Preferably, the molecular sieve is NJU120-2, and after calcination, the NJU120-2 has a three-dimensional pore system of 22×12×10-membered rings in its framework structure composed of T(Si,Al) _O4 tetrahedra.

A method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures includes the following steps:

S1, under stirring conditions, silicon source, aluminum source, organic template agent, water, and optional mineralizer ( ^F- or ^OH- ) are mixed uniformly in proportion to form a reactive gel. The chemical composition of the reactive gel is rROH:a(OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O , where R represents the positively charged group of the organic template agent; the corresponding value ranges of r, a, x _, and w are: r = 0.1-5.0, a = 0-5.0, x = 0-1.0, w = 1-100; the preferred value ranges of r, a, x, and w are: r = 0.1-2.0, a = 0-2.0, x = 0-0.5, w = 1-30.

S2, place the reaction gel under an infrared lamp or in an oven to remove excess solvent, then transfer the reaction gel to a stainless steel reactor and crystallize it under sealed conditions at a temperature of 80-240℃ for 1-60 days.

S3. After washing and drying the crystallized product, calcine it in air at 300-850℃ for 2-5 hours to remove the template agent.

Preferably, the organic template agent has a tetrahedral spatial configuration represented by the following general formula:

Wherein, _R1 and _R2 are phenyl, cyclohexyl or adamantane, _R3 and _R4 are _C1-4 alkyl (methyl, ethyl, propyl, butyl), cyclohexyl or adamantane, and X is P (phosphorus) or N (nitrogen). _R1 and _R2 are preferably adamantane, R3 _{and R4} are preferably _C1-4 alkyl, and X is preferably phosphorus.

Preferably, the organic template agent is selected from any one or more of the following:

Preferably, the silicon source is selected from at least one of silicic acid, silica gel, silica sol, tetraalkyl silicate, and water glass.

Preferably, the boron group element compound is selected from at least one of sodium aluminate, aluminum isopropoxide, aluminum sulfate hexadecoxide, aluminum hydroxide, or boric acid.

Preferably, no more than 80% of the aluminum atoms in the molecular sieve are replaced by at least one non-silicon and non-aluminum element.

Preferably, the non-silicon and non-aluminum elements are selected from at least one of the elements composed of boron, tin, zirconium, and titanium.

Preferably, in S1, the mineralizing agent used is selected from compounds containing ^F- or ^OH- ions.

Preferably, the mixture contains seed crystals at a concentration of 0.01 ppm to 10,000 ppm by weight.

Preferably, the seed crystal comprises the molecular sieve described in any one of the present invention.

A molecular sieve composition comprising the molecular sieve of the present invention, and a binder.

Preferably, the molecular sieve composition is used as an adsorbent or catalyst.

Compared with the prior art, the beneficial effects of this invention are as follows:

NJU120-1 molecular sieve features a novel 22×10×10 three-dimensional channel system, while NJU120-2 molecular sieve features a novel 22×12×10 three-dimensional channel system. These are novel, germanium-free, high-silicon or pure-silicon, fully connected, ultraporous molecular sieve materials. They not only have significant practical application value in catalysis, adsorption separation, and other fields, but also hold important theoretical significance for enriching the molecular sieve structure family.

Attached Figure Description

Figure 1 shows the more specific topological features of the framework structure of the NJU120-1 molecular sieve of the present invention;

Figure 2 shows the more specific topological features of the framework structure of the NJU120-2 molecular sieve of the present invention;

Figure 3 shows the X-ray powder diffraction pattern (Cu target Kα rays) of the NJU120-1 molecular sieve of the present invention before and after the template agent was removed by high-temperature calcination at 600℃.

Figure 4 is a schematic diagram of the pores of the NJU120-1 molecular sieve crystal structure along different directions of the present invention.

Figure 5 is a scanning electron microscope (SEM) image of the NJU120-1 molecular sieve of the present invention;

Figure 6 shows the X-ray powder diffraction pattern (Cu target Kα rays) of the NJU120-2 molecular sieve of the present invention before and after the template agent was removed by high-temperature calcination at 600℃.

Figure 7 is a schematic diagram of the pores of the NJU120-2 molecular sieve crystal structure of the present invention along different directions;

Figure 8 is a scanning electron microscope (SEM) image of the NJU120-2 molecular sieve of the present invention.

Detailed Implementation

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

Referring to Figures 1-8, the aluminosilicate molecular sieve with a large pore structure may still contain organic matter (such as organic template agents) and water in its composition immediately after synthesis. Therefore _, the schematic chemical composition of the synthesized molecular sieve is: rROH:a(OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O , where R represents the positively charged group of the organic template agent. The schematic chemical composition of the molecular sieve after calcination is: ( _HAlO₂ ) _x ·SiO₂ _, where 0≤x≤1, preferably x＝0-0.5, more preferably x＝0-0.2;

Example 1

The molecular sieve is NJU120-1, whose T (silicon, aluminum) atoms have the topological characteristics shown in Figure 1. After calcination, NJU120-1 has a three-dimensional channel system of 22×10×10-membered rings in its framework structure composed of T (Si, Al)O ₄ tetrahedra.

The molecular sieve NJU120-1 exhibits X-ray powder diffraction characteristics before and after calcination, as shown in Tables A1 and A2 below:

Table A1 X-ray powder diffraction characteristics of NJU120-1 before calcination

Table A2 X-ray powder diffraction characteristics of NJU120-1 after calcination

In the above data, w, mw, m, s, and vs represent the diffraction peak intensities, with w indicating weak, mw indicating moderate to weak, m indicating moderate, s indicating strong, and vs indicating very strong. This is known to those skilled in the art. Generally, w is less than 10, mw is 10-20, m is 20-40, s is 40-70, and vs is greater than 70.

Example 2

The molecular sieve is NJU120-2, whose T (silicon, aluminum) atoms have the topological characteristics shown in Figure 2. After calcination, NJU120-2 has a three-dimensional channel system of 22×12×10-membered rings in its framework structure composed of T (Si, Al)O ₄ tetrahedra.

NJU120-2 exhibits the X-ray powder diffraction characteristics before and after calcination, as shown in Tables A3 and A4 below:

Table A3 X-ray powder diffraction characteristics of NJU120-2 before calcination

Table A4 X-ray powder diffraction characteristics of NJU120-2 after calcination

In the above data, w, mw, m, s, and vs represent the diffraction peak intensities, with w indicating weak, mw indicating moderate to weak, m indicating moderate, s indicating strong, and vs indicating very strong. This is known to those skilled in the art. Generally, w is less than 10, mw is 10-20, m is 20-40, s is 40-70, and vs is greater than 70.

This invention also provides a method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures, comprising the following steps:

S1, under stirring conditions, silicon source, aluminum source, organic template agent, water, and optional mineralizer ( ^F- or ^OH- ) are mixed uniformly in proportion to form a reactive gel. The chemical composition of the reactive gel is rROH:a(OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O , where R represents the positively charged group of the organic template agent; the corresponding value ranges of r, a, x _, and w are: r = 0.1-5.0, a = 0-5.0, x = 0-1.0, w = 1-100; the preferred value ranges of r, a, x, and w are: r = 0.1-2.0, a = 0-2.0, x = 0-0.5, w = 1-30.

As the silicon source, any silicon source conventionally used in the art for this purpose can be used. Examples include silicic acid, silica gel, silica sol, tetraalkyl silicate, or water glass. These silicon sources can be used alone or in combination in the required proportions.

As a mineralizing agent, it can be F- ions or OH- ions; any F- or OH- ions conventionally used in the art for this purpose can be used. Examples include hydrofluoric acid, ammonium fluoride, sodium hydroxide, potassium hydroxide, etc.

As the aluminum source, any aluminum source conventionally used in the art for this purpose can be used. Examples include at least one composition of aluminum hydroxide, sodium aluminate, aluminum salts, kaolin, and montmorillonite.

S2, the reaction gel is placed under an infrared lamp or in an oven to remove excess solvent. The reaction gel is then transferred to a stainless steel reactor and, under sealed conditions, reacted at 80-240°C, preferably 120-220°C, for 1-60 days, preferably 2-45 days, more preferably 3-30 days, to induce crystallization. After crystallization, the molecular sieve can be separated from the resulting reaction mixture as a product using any conventionally known separation method, thereby obtaining molecular sieves NJU120-1 and NJU120-2, also referred to as the synthetic form of molecular sieves NJU120-1 and NJU120-2. Examples of separation methods include filtering, washing, and drying the obtained reaction mixture. Filtration, washing, and drying can be performed in any manner conventionally known in the art.

S3. After washing and drying the crystallized product, it is calcined in air at 300-850℃ for 2-5 hours to remove the template agent and any moisture present, thus obtaining the calcined molecular sieve, also known as the calcined form of molecular sieves NJU120-1 and NJU120-2. Immediately after synthesis, the molecular sieve may still contain organic matter (such as organic template agents) and water. Therefore, molecular sieves NJU120-1 and NJU120-2 may also have a schematic chemical composition as shown in the formula rROH:a(OH- or F- ₎ : _xAl₂O₃ : _SiO₂ : _wH₂O , where R represents the positively charged group of the organic template agent. Here, molecular sieves with the illustrative chemical composition "rROH:a(OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O " are calcined to remove any organic template agents and water from their pores, thereby obtaining molecular sieves with the illustrative chemical composition "( _{HAlO₂ ) x} · _SiO₂ ". Calcination can be carried out in any manner conventionally known in the art, for example, calcination temperatures are generally from 300 to 850°C, preferably 400 to 600°C, and calcination times are generally from 1 hour to 10 hours, preferably from 3 hours to 6 hours. Calcination is generally carried out in an oxygen-containing atmosphere, such as air or an oxygen atmosphere.

In the illustrative chemical composition rROH:a(OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O , _where R represents the positively charged group of the organic template agent. The organic template agent has a tetrahedral spatial configuration represented by the following general formula:

Wherein, _R1 and _R2 are phenyl, cyclohexyl or adamantane, R3 and R4 are _C1-4 alkyl (methyl, ethyl, propyl, butyl), cyclohexyl or adamantane, X is P (phosphorus) or N (nitrogen), R1 and R2 are preferably adamantane, R3 and R4 are preferably _C1-4 alkyl, and X is preferably phosphorus.

The organic template agent is selected from any one or more of the following:

Preferred These organic template agents can be used alone or in combination in the required proportions.

In molecular sieves NJU120-1 and NJU120-2, the framework Al can be partially replaced by non-silicon and non-aluminum trivalent or tetravalent elements, with a replacement rate not exceeding 80%. Here, the parameter "replacement rate" is dimensionless. The non-silicon and non-aluminum elements are selected from at least one of boron, tin, zirconium, and titanium. For example, when aluminum is replaced by the _trivalent element boron, the replacement rate = 2 × _2O₃ / (2 _{× 2O₃} + _2Al₂O₃ ) × 100% _, where X is the trivalent element; when aluminum is replaced by the tetravalent element, the replacement rate = _YO₂ / ( _YO₂ + _2Al₂O₃ ) × 100%, where Y is the tetravalent element. The molar number of the corresponding oxide is used when calculating the replacement rate. When replacing aluminum atoms with trivalent or tetravalent non-silicon and non _- aluminum elements, a source of non-silicon and non-aluminum trivalent or tetravalent elements must be added to the mixture, preferably an oxide source of non-silicon and non-aluminum trivalent or tetravalent elements. As the aforementioned oxide source, preferably one is selected from the group consisting of boron oxide source, tin oxide source, zirconium oxide source, and titanium oxide source. Specifically, as a boron oxide source, at least one can be selected from the group consisting of boron oxide, borax, sodium metaborate, and boric acid. Specifically, as a tin oxide source, at least one can be selected from the group consisting of tin tetrachloride, stannous chloride, alkyltin, alkoxytin, and organostannate. Specifically, as a zirconium oxide source, one can be selected from the group consisting of zirconium salts (zirconium nitrate, zirconium sulfate), alkylzirconium, alkoxyzirconium, and organozirconate. Specifically, as a titanium oxide source, one or more can be selected from the group consisting of tetraalkyl titanates (such as tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate), _TiCl₄ , hexafluorotitanic acid, titanium sulfate, and their hydrolysis products.

Molecular sieves NJU120-1 and NJU120-2 can be used in combination with other materials to obtain molecular sieve compositions.

Molecular sieves NJU120-1 and NJU120-2 or a molecular sieve composition can be used as adsorbents, for example, to separate at least one component from a mixture of multiple components in the gas or liquid phase by contacting the mixture with molecular sieves NJU120-1 and NJU120-2 or a molecular sieve composition to selectively adsorb the component.

Molecular sieves NJU120-1 and NJU120-2, or a combination of molecular sieves, can be used directly or after undergoing necessary treatments or transformations (such as ion exchange) conventionally performed on molecular sieves in the art, and thus as catalysts (or as catalytically active components). Therefore, according to one aspect of the invention, reactants can be subjected to a predetermined reaction in the presence of a catalyst to obtain the target product.

In order to illustrate the present invention more clearly, the following embodiments are provided. These embodiments do not limit the scope of protection of this patent in any way.

Example 1

Taking template agent 4 as an example, the general synthesis process of the template agent is illustrated. 17.93 g of n-butylbis(1-adamantyl)phosphine and 200 ml of toluene were mixed in a 500 ml round-bottom flask. At room temperature, 14.25 g of iodomethane was added dropwise to the mixture. The system was reacted at room temperature with stirring for one day. The reaction mixture was subjected to rotary evaporation to remove the solvent, yielding a crude product. Recrystallization from methanol yielded 30.55 g of the product, with a yield of 95%. The product was characterized by liquid NMR (D₂O) and electrospray mass spectrometry, confirming it as the target compound. The obtained product was dispersed in 400 ml of deionized water and subjected to column exchange using a pre-treated IRN-78 strong-base anion exchange resin (manufacturer: Thermo Fisher), yielding an aqueous solution of template agent 6. An appropriate amount of this solution was weighed and standardized with 0.1 mol/L hydrochloric acid solution, using phenolphthalein as an indicator. The standardized structure confirmed that the exchange efficiency of iodide salt to hydroxide ions reached 97%.

Example 2

The gel synthesized from molecular sieves was prepared according to a molar ratio of 0.5 ROH:0.025 Al₂O₃:SiO₂:15 H₂O. The general steps are as follows: Weigh an appropriate amount of the template agent solution from Example 1 after exchange, add 0.03 mmol (0.007 g) of aluminum isopropoxide powder, and stir for about half an hour. Then add 1.4 mmol (0.291 g) of tetraethyl orthosilicate and stir at room temperature for about two hours until the tetraethyl orthosilicate is completely dissolved. After stirring until homogeneous, place the mixed gel under an infrared lamp or in an oven at 80°C to remove excess solvent. Transfer the final reaction gel to a 5 ml stainless steel reactor with a polytetrafluoroethylene liner and react at 190°C for 24 days under sealed conditions. The product is washed twice with water and twice with ethanol, and then dried for later use. The product was directly identified by X-ray powder diffraction and confirmed as NJU-120-1. Take an appropriate amount of sample and calcine it in an air atmosphere at 600℃ for 2 hours in a muffle furnace to remove the template agent. The product is washed with water, centrifuged and dried to obtain NJU120-1 molecular sieve product.

Example 3

The gel synthesized from molecular sieves was prepared according to a molar ratio of 0.5 ROH:0.033 Al2O3:SiO2:15 H2O. The general steps are as follows: Weigh an appropriate amount of the template agent solution from Example 1 after exchange, add 0.04 mmol (0.009 g) of aluminum isopropoxide powder, stir for about half an hour, then add 1.4 mmol (0.297 g) of tetraethyl orthosilicate, stir at room temperature for about two hours until the tetraethyl orthosilicate is completely dissolved, and stir evenly. Place the mixed gel under an infrared lamp or in an oven at 80°C to remove excess solvent. Transfer the final reaction gel to a 5 ml stainless steel reactor with a polytetrafluoroethylene liner, and react at 190°C for 24 days under sealed conditions. The product is washed twice with water and twice with ethanol, and then dried for later use. The product was directly identified by X-ray powder diffraction and confirmed to be NJU-120-1. Take an appropriate amount of sample and calcine it in an air atmosphere at 600℃ for 2 hours in a muffle furnace to remove the template agent. The product is washed with water, centrifuged and dried to obtain NJU120-1 molecular sieve product.

Example 4

The gel synthesized from molecular sieves was prepared according to a molar ratio of 0.5 ROH:0.025 Al₂O₃:0.3 HF:SiO₂:15 H₂O. The general steps were as follows: An appropriate amount of the template agent solution from Example 1 (after exchange) was weighed, and 0.03 mmol (0.007 g) of aluminum isopropoxide powder was added. The mixture was stirred for about half an hour, followed by the addition of 1.4 mmol (0.291 g) of tetraethyl orthosilicate. The mixture was stirred at room temperature for about two hours until the tetraethyl orthosilicate was completely dissolved. Then, the corresponding amount of hydrofluoric acid solution was added according to the above ratio, and the mixture was stirred until homogeneous. The mixed gel was placed under an infrared lamp or in an oven at 80°C to remove excess solvent. The final reaction gel was transferred to a 5 ml stainless steel reactor with a polytetrafluoroethylene liner and reacted at 175°C for 42 days under sealed conditions. The product was washed twice with water and twice with ethanol, and then dried for later use. The product was directly identified by X-ray powder diffraction and confirmed to be NJU-120-1. Take an appropriate amount of sample and calcine it in an air atmosphere at 600℃ for 2 hours in a muffle furnace to remove the template agent. The product is washed with water, centrifuged and dried to obtain NJU120-1 molecular sieve product.

Example 5

The gel synthesized from molecular sieves was prepared according to a molar ratio of 0.5 ROH:0.050 Al₂O₃:SiO₂:5 H₂O. The general steps are as follows: Weigh an appropriate amount of the template agent solution from Example 1 after exchange, add 0.06 mmol (0.014 g) of aluminum isopropoxide powder, stir for about half an hour, then add 1.4 mmol (0.297 g) of tetraethyl orthosilicate, stir at room temperature for about two hours until the tetraethyl orthosilicate is completely dissolved, and stir evenly. Place the mixed gel under an infrared lamp or in an oven at 80°C to remove excess solvent. Transfer the final reaction gel to a 5 ml stainless steel reactor with a polytetrafluoroethylene liner, and react at 175°C for 42 days under sealed conditions. The product is washed twice with water and twice with ethanol, and then dried for later use. The product was directly identified by X-ray powder diffraction and confirmed to be NJU-120-1. Take an appropriate amount of sample and calcine it in an air atmosphere at 600℃ for 2 hours in a muffle furnace to remove the template agent. The product is washed with water, centrifuged and dried to obtain NJU120-2 molecular sieve product.

Example 6

The gel synthesized from molecular sieves was prepared according to a molar ratio of 0.5 ROH: _{0.033 Al₂O₃} : _SiO₂ : _8H₂O . The general steps are as follows: Weigh an appropriate amount of the template agent solution from Example 1 after exchange, add 0.04 mmol (0.009 g) of aluminum isopropoxide powder, stir for about half an hour, then add 1.4 mmol (0.297 g) of tetraethyl orthosilicate, stir at room temperature for about two hours until the tetraethyl orthosilicate is completely dissolved, and stir evenly. Place the mixed gel under an infrared lamp or in an oven at 80°C to remove excess solvent. Transfer the final reaction gel to a 5 ml stainless steel reactor with a polytetrafluoroethylene liner, and react at 190°C for 14 days under sealed conditions. The product is washed twice with water and twice with ethanol, and then dried for later use. The product was directly identified by X-ray powder diffraction and confirmed to be NJU-120-2. Take an appropriate amount of sample and calcine it in an air atmosphere at 600℃ for 2 hours in a muffle furnace to remove the template agent. The product is washed with water, centrifuged and dried to obtain NJU120-2 molecular sieve product.

Three-dimensional electron diffraction (3DED) tests were performed on the molecular sieves of Examples 2-6. The structural analysis results showed that the NJU-120-1 molecular sieve structure has orthogonal symmetry and belongs to the Imma space group, while the NJU-120-2 molecular sieve structure has monoclinic symmetry and belongs to the P21/n space group. Topological analysis was performed using the crystallographic structure files (CIF files) obtained after cRED testing. The topological analysis software was ToposPro 5.3.0.2, and the analysis procedure and methods were based on the operation manual provided on the official website of the software (see ToposPro website: https://topospro.com/software/). The analysis results showed that the NJU120-1 molecular sieve framework structure has 14 topologically independent T atoms. More specific topological features of the NJU120-1 molecular sieve framework structure are shown in Figure 1. The NJU120-2 molecular sieve framework has 28 topologically independent T atoms. More specific topological features of the NJU120-2 molecular sieve framework are shown in Figure 2.

The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims (19)

An aluminosilicate molecular sieve with an ultra-large pore structure is characterized in that the schematic chemical composition of _the molecular sieve in its synthesized state is: rROH:a(OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O , and the schematic chemical composition of the molecular sieve after calcination is: ( _HAlO₂ ) _x · _SiO₂ . According to claim 1, the aluminosilicate molecular sieve with an ultra-large pore structure is characterized in that the molecular sieve is NJU120-1, and after calcination, the NJU120-1 has a three-dimensional pore system of 22×10×10-membered rings in its framework structure composed of T(Si,Al) _O4 tetrahedra. According to claim 2, the aluminosilicate molecular sieve with a large pore structure is characterized in that the molecular sieve NJU120-1 has X-ray powder diffraction characteristics before and after calcination as shown in Tables A1 and A2 below. Table A1 X-ray powder diffraction characteristics of NJU120-1 before calcination

Table A2 X-ray powder diffraction characteristics of NJU120-1 after calcination

The aluminosilicate molecular sieve with ultra-large pore structure according to claims 2-3 is characterized in that the T (silicon, aluminum) atoms of the NJU120-1 have the topological characteristics shown in the figure below.
According to claim 1, the aluminosilicate molecular sieve with an ultra-large pore structure is characterized in that the molecular sieve is NJU120-2, and after calcination, the NJU120-2 has a three-dimensional pore system of 22×12×10-membered rings in its framework structure composed of T(Si,Al) _O4 tetrahedra. According to claim 5, the aluminosilicate molecular sieve with a large pore structure is characterized in that the NJU120-2 has X-ray powder diffraction characteristics before and after calcination as shown in Tables A3 and A4 below. Table A3 X-ray powder diffraction characteristics of NJU120-2 before calcination

Table A4 X-ray powder diffraction characteristics of NJU120-2 after calcination

The aluminosilicate molecular sieve with ultra-large pore structure according to claims 5-6 is characterized in that the T (silicon, aluminum) atoms of the NJU120-2 have the topological characteristics shown in the figure below.
(Continued from the table above)
The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claims 1-7 is characterized by comprising the following steps: S1, under stirring conditions, silicon source, aluminum source, organic template agent, water, and optional mineralizer ( ^F- or ^OH- ) are mixed uniformly in proportion to form a reactive gel. The chemical composition of the reactive gel is rROH:a(OH- or F-): _xAl₂O₃ : _SiO₂ : _wH₂O , where R represents the positively charged group of the organic template agent; the corresponding value ranges of r, a, x _, and w are: r = 0.1-5.0, a = 0-5.0, x = 0-1.0, w = 1-100; the preferred value ranges of r, a, x, and w are: r = 0.1-2.0, a = 0-2.0, x = 0-0.5, w = 1-30. S2, place the reaction gel under an infrared lamp or in an oven to remove excess solvent, then transfer the reaction gel to a stainless steel reactor and crystallize it under sealed conditions at a temperature of 80-240℃ for 1-60 days. S3. After washing and drying the crystallized product, calcine it in air at 300-850℃ for 2-5 hours to remove the template agent. The method for synthesizing aluminosilicate molecular sieves with ultra-large porous structures according to claim 8 is characterized in that the organic template agent has a tetrahedral spatial configuration represented by the following general formula:
Wherein, _R1 and _R2 are phenyl, cyclohexyl or adamantane, _R3 and _R4 are _C1-4 alkyl (methyl, ethyl, propyl, butyl), cyclohexyl or adamantane, and X is P (phosphorus) or N (nitrogen). _R1 and R2 are preferably adamantane, R3 and R4 are preferably _C1-4 alkyl, and X is preferably phosphorus. The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claim 9 is characterized in that the organic template agent is selected from any one or more of the following:

The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claim 8 is characterized in that the silicon source is selected from at least one of silicic acid, silica gel, silica sol, tetraalkyl silicate, and water glass. The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claim 8 is characterized in that the boron group element compound is selected from at least one of sodium aluminate, aluminum isopropoxide, aluminum sulfate hexadecylhydrate, aluminum hydroxide, or boric acid. The method for synthesizing the aluminosilicate molecular sieve with an ultra-large pore structure according to claim 8 is characterized in that no more than 80% of the aluminum atoms in the molecular sieve are replaced by at least one non-silicon and non-aluminum element. The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claim 13 is characterized in that the non-silicon and non-aluminum elements are selected from at least one of the elements composed of boron, tin, zirconium and titanium. The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claim 8 is characterized in that, in step S1, the mineralizing agent used is selected from compounds containing ^F- or ^OH- ions. The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claim 8 is characterized in that the mixture contains seed crystals of 0.01 ppm to 10,000 ppm by weight. The method for synthesizing aluminosilicate molecular sieves with ultra-large pore structures according to claim 8 is characterized in that the seed crystal comprises the molecular sieve according to any one of claims 1-7. A molecular sieve composition, characterized in that it comprises a molecular sieve according to any one of claims 1-7 or a molecular sieve synthesized by the method according to any one of claims 8-17, and a binder. The molecular sieve composition according to claim 18 is characterized in that it is used as an adsorbent or catalyst.