Mesoporous silicate molecular sieve as well as preparation method and application thereof

Abstract

The invention provides a mesoporous silicate molecular sieve as well as a preparation method and application thereof, and belongs to the technical field of molecular sieves. The framework component of the mesoporous silicate molecular sieve provided by the invention is only silica, 14 kinds of topology independent atoms are contained in the framework, a 36-membered ring one-dimensional mesoporous channel system is contained in the crystal structure of the mesoporous silicate molecular sieve, and the material is good in thermal stability and can be applied as a catalyst or an adsorbent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of molecular sieves, and particularly relates to a mesoporous silicate molecular sieve and a preparation method and application thereof. BACKGROUND

[0002] Silicate molecular sieve materials are widely used in catalysis and adsorption separation fields. The nanoscale confined space provided by the silicate molecular sieve materials can provide suitable shape-selective effect for specific guest molecules. Each type of molecular sieve has its own special pore system. According to the pore size of the porous material, it can be divided into microporous (pore diameter less than 2 nm), mesoporous (pore diameter of 2-50 nm) and macroporous (pore diameter greater than 50 nm). Among them, the microporous molecular sieve can be divided into small pores, medium pores, large pores and super large pores, which correspond to 8-membered rings and below, 9-10-membered rings, 11-12-membered rings and more than 12-membered rings, respectively. At the same time, the molecular sieves can also be divided into one-dimensional, two-dimensional and three-dimensional pore molecular sieves according to the connectivity of the pore system in the molecular sieves.

[0003] The crystalline molecular sieve materials with specific structures need to be further distinguished by powder X-ray diffraction: because their crystal structures are different, the pore systems are also completely different, so they show completely different pattern characteristics in the diffraction experiment. Taking known molecular sieves as an example, A-type zeolite (see US2882243A), Y-type zeolite (see US3130007A), etc., all have their own unique diffraction patterns. In addition, molecular sieve materials with different topological structures also show their own unique topological characteristics. According to the definition and explanation of the International Zeolite Association, each type of molecular sieve framework topological type can be uniquely determined by its coordination sequence (Coordination Sequences) and vertex symbol (Vertex Symbols). Both parameters can be used as a basis for distinguishing different framework structures (see the official website of the International Zeolite Association https: / / europe.iza-structure.org / IZA-SC / DatabaseHelp_Structures.html#CS).

[0004] Traditional microporous molecular sieves generally have long-range ordered crystal structures, which make them have high stability and are sufficient to handle most substrates below 1 nm. However, with the increasing demand for processing of large molecule substrates in the fields of petroleum refining, waste plastic recycling, special organic reactions and life sciences, it is urgent to develop new molecular sieve materials with large size regular pores.

[0005] The discovery of ordered mesoporous materials in the late 20th century was a milestone in the field of porous material creation. Mobil Corporation successfully prepared the M41S series of mesoporous materials using surfactants as template agents, expanding the pore size of ordered porous materials to more than 2 nm. Since then, the advent of new mesoporous materials such as SBA-15, MAS-9, and others has continuously broken through the limits of pore size and stability. However, the intrinsic characteristic of long-range disorder at the atomic scale of such ordered mesoporous materials makes their thermal stability and hydrothermal stability relatively low, which still needs to be improved. Therefore, strategies such as zeolitization of pore walls and mesoporous zeolite have been designed to build a multi-level pore system to solve this problem, but they still face the challenges of non-uniform mesopore size and difficulty in generating through mesopores, making shape-selective catalysis of macromolecular substrates difficult to perform.

[0006] Another viable option is to expand the pore size limit of crystalline microporous molecular sieves, which greatly depends on the design of organic template agents. In 2021, the team of Chen Feijian synthesized the first stable zeolite with a three-dimensional super-large pore cross system using a large-volume and stable quaternary phosphonium salt template agent, opening up the exploration of phosphorus-based template agents to synthesize new stable super-large pore zeolites (CN114538466A). Since then, the emergence of various stable super-large pore zeolites such as ZEO-3 (CN115611293A), ZEO-5, NJU120-1, NJU120-2 (CN120157148A), and others has continuously refreshed the pore size limit of microporous molecular sieves. Until the appearance of ZMQ-1 (CN118515294A), the upper limit of crystalline pore size was raised to the mesoporous level. Unfortunately, the narrow pore leads to a maximum free sphere diameter of only 1.2 nm, and the design of traditional microporous template agents restricts the breakthrough of such materials beyond the microporous limit. Therefore, it is still difficult to obtain crystalline mesoporous molecular sieves with uniform pore size and long-range order.

[0007] In summary, the creation of regular crystalline pore materials with mesoporous size is still lacking in practice. SUMMARY

[0008] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a mesoporous silicate molecular sieve, a preparation method thereof, and an application thereof. The silicate molecular sieve has a one-dimensional mesoporous pore system with a 36-membered ring, a long-range order at the atomic scale, and good stability, and can be used as a catalyst or an adsorbent.

[0009] To achieve this purpose, the present application adopts the following technical solutions:

[0010] In a first aspect, the present application provides a mesoporous silicate molecular sieve, which has the following X-ray powder diffraction characteristics:

[0011]

[0012]

[0013] wherein relative intensity = I / I0 x 100, I is the intensity of the diffraction peak, and I0 is the intensity of the strongest diffraction peak. w, mw, m, s, vs represent the relative intensity of the diffraction peak, w is weak, mw is medium weak, m is medium, s is strong, and vs is very strong, which 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.

[0014] In some embodiments of the present application, the mesoporous silicate molecular sieve has a one-dimensional mesopore channel system with 36-membered rings in the crystal structure of the mesoporous silicate molecular sieve.

[0015] In some embodiments of the present application, the mesoporous silicate molecular sieve has 14 topologically independent T atoms in the framework, and the topological characteristics are as follows:

[0016]

[0017]

[0018] wherein T represents a Si atom.

[0019] From T1 to T14, the 14 topologically independent T atoms in the framework structure of the mesoporous silicate molecular sieve JU-69 of the present application are represented; from N1 to N12, the coordination sequences of the T atoms from the first layer to the twelfth layer are represented. Due to the different naming orders of the T atoms, the 14 topologically independent T atoms named in different orders may not correspond one-to-one to the coordination sequences of the T atom orders in the table, but the structures belonging to the topology of the mesoporous silicate molecular sieve of the present application all contain and only contain the coordination sequences of the 14 topologically independent T atoms in the table, and the coordination sequences correspond one-to-one.

[0020] In some embodiments of the present application, the mesoporous silicate molecular sieve has a chemical composition of SiO 2.079 .

[0021] The present application designs a kind of organic template with dumbbell-shaped configuration, and synthesizes a crystalline mesoporous silicate molecular sieve (named JU-69 in the present application) using the same. The mesoporous silicate molecular sieve has crystalline pore walls, and its crystal structure is long-range ordered at atomic scale like microporous molecular sieve, which is different from traditional ordered mesoporous materials. Moreover, the mesoporous silicate molecular sieve provided by the present application has a one-dimensional mesoporous pore system with 36-membered rings, the minimum size of the pore opening is more than 2 nm, and there is no microporous channel, which breaks through the microporous limitation of crystalline zeolite molecular sieve. In addition, the mesoporous silicate molecular sieve provided by the present application has a pure siloxane skeleton component, which makes it have good stability.

[0022] The mesoporous silicate molecular sieve provided by the present application not only has very important practical application value (for example, used as a catalyst or an adsorbent), but also has important theoretical and guiding significance for enriching the molecular sieve structure family and further breaking through the channel limit of crystalline zeolite molecular sieve.

[0023] In a second aspect, the present application provides a preparation method of the mesoporous silicate molecular sieve according to the first aspect, which comprises the following steps:

[0024] (1) mixing a silicon source, an organic template and water, aging under alkaline conditions, removing excess solvent to obtain a gel;

[0025] (2) crystallizing the gel to obtain a crystallization product;

[0026] (3) calcining the crystallization product to remove the organic template to obtain the mesoporous silicate molecular sieve;

[0027] The cation of the organic template is selected from one or more of the cations having the structures shown in the following general formula:

[0028]

[0029] R1 and R2 are adamantyl groups;

[0030] R3 is a methyl group, an ethyl group, a propyl group or a butyl group, preferably an ethyl group or a butyl group, more preferably an ethyl group;

[0031] X is phosphorus or nitrogen, preferably phosphorus;

[0032] n represents the number of methylene groups, and is an integer from 2 to 16 (for example, it can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16), preferably an integer from 6 to 12, more preferably an integer from 10 to 12.

[0033] It is to be noted that the basic condition in step (1) can be achieved by using a basic organic template agent (e.g. the anion of the organic template agent is OH - ); or a non-basic organic template agent (e.g. the anion of the organic template agent is Cl - , Br - or I - ), and adjusting the pH to basic by adding a pH adjuster (e.g. NaOH, KOH) afterwards.

[0034] In some embodiments of the present application, the cation of the organic template agent is selected from one or more of the following cations:

[0035]

[0036] The specific structural formulae of these cations are shown in the following table:

[0037]

[0038]

[0039] In some preferred embodiments of the present application, the cation of the organic template agent is selected from one or more of the following cations:

[0040]

[0041] In some preferred embodiments of the present application, the cation of the organic template agent is selected from one or more of the following cations:

[0042]

[0043] In some embodiments of the present application, the anion of the organic template agent is selected from one or more of OH - , Cl - , Br - and I - , preferably OH - .

[0044] In some embodiments of the present application, the chemical composition of the gel is SiO2: rROH: wH2O;

[0045] wherein R represents the cation of the organic template agent, and r, w respectively represent the equivalent of the corresponding component when the Si amount is 1.

[0046] r = 0.05-1, for example, can be 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, 0.25, 0.28, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1, etc., preferably r = 0.05-0.5;

[0047] w = 1-100, for example, can be 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 12, 15, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90 or 100, etc.; preferably w = 1-10.

[0048] However, the present application is not limited to the listed values, other unlisted values within the above ranges are also applicable.

[0049] It should be noted that ROH in the present application is only used to represent the type of anion and cation in the molecule, and is not a chemical formula, i.e., the ratio of cation (R) and anion (OH) in the molecule is not 1:1.

[0050] In the present application, the type of the silicon source is not particularly limited, which can be a silicon source known in the art for preparing mesoporous silicate molecular sieves. For example, the silicon source can be selected from one or more of silicic acid, silica gel, silica sol, tetraalkyl silicate and water-soluble silicate. As a non-limiting example, the water-soluble silicate can be water glass.

[0051] In some embodiments of the present application, seeds are further added in the mixing step in step (1), and the seeds are the crystallization product in step (2) and / or the mesoporous silicate molecular sieve of the first aspect.

[0052] In the present application, the crystallization product only removes the organic template agent in the calcination process, and the framework structure does not change, so the crystal structure is the same as that of the prepared mesoporous silicate molecular sieve. By adding the crystallization product and / or the mesoporous silicate molecular sieve as seeds, the nucleation energy barrier of the crystals in the gel crystallization process is reduced, the crystallization is easier to occur, and the crystallization speed is faster.

[0053] As a person skilled in the art would readily understand, the crystallization product and the mesoporous silicate molecular sieve can also be prepared without adding seeds in the present application, and the prepared crystallization product and the mesoporous silicate molecular sieve can be used as seeds in the subsequent preparation process.

[0054] In some embodiments of the present application, the mass content of the seed crystal in the gel is 0.01-10000 ppm; for example, it can be 0.01 ppm, 0.1 ppm, 1 ppm, 5 ppm, 10 ppm, 50 ppm, 100 ppm, 200 ppm, 300 ppm, 500 ppm, 600 ppm, 800 ppm, 1000 ppm, 2000 ppm, 3000 ppm, 5000 ppm, 6000 ppm, 8000 ppm or 10000 ppm, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0055] In some embodiments of the present application, the aging method is stirring at a temperature of 15-30°C (for example, it can be 15°C, 18°C, 20°C, 22°C, 23°C, 25°C, 26°C, 28°C or 30°C, etc.) for 2-24 h (for example, it can be 2 h, 3 h, 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h or 24 h, etc.). However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0056] In the present application, the method for removing excess solvent is not particularly limited, and can be routinely selected by those skilled in the art. For example, infrared light irradiation or oven baking can be used.

[0057] In some embodiments of the present application, the crystallization temperature is 80-240°C, for example, it can be 80°C, 90°C, 100°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 220°C, 230°C or 240°C, etc.; preferably, it is 80-220°C, more preferably, it is 100-190°C. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0058] In some embodiments of the present application, the crystallization time is 1-60 days, for example, it can be 1 day, 2 days, 3 days, 5 days, 6 days, 8 days, 10 days, 12 days, 15 days, 18 days, 20 days, 22 days, 25 days, 28 days, 30 days, 35 days, 40 days, 45 days, 50 days, 55 days or 60 days, etc.; preferably, it is 1-45 days, more preferably, it is 1-30 days. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable.

[0059] In some embodiments of the present application, the preparation method further comprises washing and drying the obtained product after the crystallization.

[0060] The washing and drying can be performed in a conventional manner known in the art. For example, the washing can be performed using water or ethanol for multiple times; and the drying can be performed using an oven.

[0061] In some embodiments of the present application, the calcination temperature is 400-650℃, for example, it can be 400℃, 420℃, 450℃, 480℃, 500℃, 520℃, 550℃, 580℃, 600℃, 620℃ or 650℃, etc.; and the time is 2-6h, for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, etc. However, the present application is not limited to the listed values, and other unlisted values within the range are also applicable. It should be noted that the calcination time refers to the time after the calcination temperature is reached, and does not include the heating time.

[0062] In some embodiments of the present application, the atmosphere during the calcination is air, oxygen, hydrogen, nitrogen or an inert element gas. Among them, the inert element gas can be one or more of helium, neon and argon.

[0063] In some embodiments of the present application, the atmosphere during the calcination is air or oxygen, and the preparation method further comprises: after the calcination, washing and drying the obtained product.

[0064] In the present application, when the atmosphere during the calcination is air or oxygen, and the template agent contains phosphorus, phosphorus oxide may be left in the product after the calcination, and therefore the calcination product is washed at this time to remove the phosphorus oxide.

[0065] In a third aspect, the present application provides a molecular sieve composition, which comprises: the mesoporous silicate molecular sieve according to the first aspect or the mesoporous silicate molecular sieve prepared by the preparation method according to the second aspect, and a binder.

[0066] In a fourth aspect, the present application provides the use of the mesoporous silicate molecular sieve according to the first aspect, the mesoporous silicate molecular sieve prepared by the preparation method according to the second aspect or the molecular sieve composition according to the third aspect as a catalyst or an adsorbent.

[0067] Compared with the prior art, the present application has the following beneficial effects:

[0068] The present application designs a kind of organic template with dumbbell-shaped configuration, and synthesizes a crystalline mesoporous silicate molecular sieve by using it.The mesoporous silicate molecular sieve has crystalline pore wall, and its crystal structure is long-range ordered on atomic scale like microporous molecular sieve, which is different from traditional ordered mesoporous material.Further, the mesoporous silicate molecular sieve provided by the present application has 36-membered ring one-dimensional mesoporous pore system, and the minimum size of pore opening is more than 2nm, and there is no microporous channel, which breaks through the microporous limit of crystalline zeolite molecular sieve.In addition, the mesoporous silicate molecular sieve provided by the present application has pure siloxane skeleton component, which makes it have good stability.

[0069] The mesoporous silicate molecular sieve provided by the present application not only has very important practical application value (for example, used for catalyst or adsorbent), but also has important theoretical and guiding significance for enriching the molecular sieve structure family and further breaking through the channel limit of crystalline zeolite molecular sieve. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1 X-ray powder diffraction pattern of the mesoporous silicate molecular sieve provided for the embodiment 1 of the present application;

[0071] Figure 2 SEM image of the mesoporous silicate molecular sieve provided for the embodiment 1 of the present application;

[0072] Figure 3 Crystal structure diagram of the mesoporous silicate molecular sieve provided for the embodiment of the present application in bc plane;

[0073] Figure 4 Crystal structure diagram of the mesoporous silicate molecular sieve provided for the embodiment of the present application in ac plane;

[0074] Figure 5 Crystal structure diagram of the mesoporous silicate molecular sieve provided for the embodiment of the present application in ab plane. DETAILED DESCRIPTION

[0075] The technical solutions of the present application will be further described below by combining with the drawings and through specific embodiments. It should be understood by those skilled in the art that the specific embodiments are only used to help understanding the present application, and should not be regarded as specific limitation to the present application.

[0076] Synthesis of organic template:

[0077] The general synthesis method of organic template is described below by taking organic templates 4-1 and 4-2 as examples.

[0078] The cations of organic templates 4-1 and 4-2 are both

[0079] The anion of organic template 4-1 is I -The anion of the organic template 4-2 is OH - .

[0080] (1) 50 g of di-1-adamantyl phosphine and 40 mL of iodoethane were dissolved in 150 mL of di-n-butyl ether, and the reaction was carried out overnight under argon protection and at 130°C. After the reaction was completed, it was cooled to room temperature, and the reaction system was diluted with excess methyl tert-butyl ether, stirred for half an hour, and then filtered, and the solvent was removed by suction, to obtain 77.61 g of white solid, with a yield of 99%. The intermediate product was di-(1-adamantyl)ethyl phosphine iodate. The product was characterized by liquid nuclear magnetic resonance (CDCl3) and electrospray mass spectrometry, and was confirmed to be the target compound.

[0081] (2) 50 g of the intermediate product obtained in step (1) and 4.22 g of NaOH were added to 150 mL of acetonitrile, and the reaction was refluxed under argon protection for half an hour. Then, 17.30 g of 1,12-dibromododecane was added to the system, and the reaction was refluxed overnight under argon protection. After the reaction was completed, it was cooled to room temperature. After the reaction mixture was subjected to rotary evaporation to remove the excess solvent, the product was washed out with chloroform, and the inorganic salt was removed by filtration. The chloroform solution was concentrated, and the product was precipitated in methyl tert-butyl ether, to obtain 55.82 g of solid, with a yield of 95%. The product was the organic template 4-1, and the product was characterized by liquid nuclear magnetic resonance (CDCl3) and electrospray mass spectrometry, and was confirmed to be the target compound.

[0082] (3) The obtained organic template 4-1 was dispersed in 400 mL of deionized water, and column exchange was performed using a pre-treated 717 strong base type anion exchange resin (manufacturer: National Pharmaceutical Group), to obtain an aqueous solution of the organic template 4-2. An appropriate amount of the solution was weighed, and was calibrated with a 0.1 mol / L hydrochloric acid solution, with phenothalin as an indicator. The calibration result showed that the exchange efficiency of iodine salt to hydroxyl group reached 92%.

[0083] The above is a general synthesis method of the template, and other templates can be synthesized by replacing the corresponding raw materials according to the above method.

[0084] Example 1

[0085] This example provides a mesoporous silicate molecular sieve, and a preparation method thereof is as follows:

[0086] (1) An aqueous solution of the organic template 4-2 (containing 1 mmol of the template) was taken, and 2 mmol (0.5285 g) of tetraethyl orthosilicate was added thereto, which was stirred at room temperature for 2 h, and then the mixture was placed in an oven at 80°C to remove the excess solvent, to obtain a gel;

[0087] The chemical composition of the gel is SiO2:0.5ROH:5H2O, wherein ROH represents the organic template 4-2;

[0088] (2) The gel was transferred into a 5 mL stainless steel autoclave with a Teflon liner and reacted at 175°C for 28 days under sealed conditions. The product was washed with water twice, washed with ethanol twice, and dried to obtain a crystallized product;

[0089] (3) A proper amount of the crystallized product was calcined at 600°C for 2 hours in an air atmosphere in a muffle furnace to remove the template. The product was washed with water, centrifuged, and dried to obtain a mesoporous silicate molecular sieve.

[0090] Example 2

[0091] This example provides a mesoporous silicate molecular sieve, the preparation method of which is as follows:

[0092] (1) A water solution of the organic template 4-2 (containing 6 mmol of the template) was taken, 20 mmol (5.285 g) of tetraethyl orthosilicate was added thereto, and the mixture was stirred at room temperature for 2 h. Then, the mixture was placed in an oven at 80°C to remove the excess solvent, to obtain a gel;

[0093] The chemical composition of the gel is SiO2:0.3ROH:7H2O, wherein ROH represents the organic template 4-2;

[0094] (2) The gel was transferred into a 20 mL stainless steel autoclave with a Teflon liner and reacted at 190°C for 7 days under sealed conditions. The product was washed with water twice, washed with ethanol twice, and dried to obtain a crystallized product;

[0095] (3) A proper amount of the crystallized product was calcined at 600°C for 2 hours in an air atmosphere in a muffle furnace to remove the template. The product was washed with water, centrifuged, and dried to obtain a mesoporous silicate molecular sieve.

[0096] Example 3

[0097] This example provides a mesoporous silicate molecular sieve, the preparation method of which is as follows:

[0098] (1) A water solution of the organic template 4-2 (containing 60 mmol of the template) was taken, 100 mmol (26.426 g) of tetraethyl orthosilicate was added thereto, and the mixture was stirred at room temperature for 2 h. Then, the mixture was placed in an oven at 80°C to remove the excess solvent, to obtain a gel;

[0099] The chemical composition of the gel is SiO2:0.6ROH:4H2O, wherein ROH represents the organic template 4-2;

[0100] (2) The gel was transferred into a 100 mL stainless steel autoclave with a Teflon liner and reacted at 140°C for 14 days under sealed conditions. The product was washed with water twice, washed with ethanol twice, and dried to obtain a crystallized product;

[0101] (3) Take an appropriate amount of the obtained crystallized product, and calcine in a muffle furnace at 600 DEG C in an air atmosphere for 2 hours to remove the template agent, and the product is washed with water, centrifuged and dried to obtain the mesoporous silicate molecular sieve.

[0102] The molecular sieve materials of Examples 1-3 are all still structurally clear after high-temperature calcination at 600 DEG C, indicating that the structures are stable.

[0103] Material characterization:

[0104] 1. The mesoporous silicate molecular sieve is subjected to phase identification by powder X-ray diffraction (light source is Cu target Kα ray).

[0105] The characterization results of the mesoporous silicate molecular sieve provided by Example 1 are shown in Table 1 and Table 2. Figure 1

[0106] Table 1

[0107]

[0108]

[0109] Among them, the relative intensity = I / I0 x 100, I is the intensity of the diffraction peak, I0 is the intensity of the strongest diffraction peak. w, mw, m, s, vs represent the relative intensity of the diffraction peak, w is weak, mw is medium weak, m is medium, s is strong, vs is very strong, which is known by 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.

[0110] The X-ray powder diffraction characteristics of the mesoporous silicate molecular sieves provided by Examples 2-3 are basically the same as those of Example 1.

[0111] 2. The composition of the mesoporous silicate molecular sieve is analyzed by ICP. The results show that the silicon-phosphorus ratio of the mesoporous silicate molecular sieves provided by Examples 1-3 is above 910:1, and the phosphorus element in the organic template agent has been basically removed.

[0112] 3. The morphology of the mesoporous silicate molecular sieve is observed by scanning electron microscope (SEM). The SEM image of the mesoporous silicate molecular sieve provided by Example 1 is shown in Table 2. Figure 2

[0113] 4. The mesoporous silicate molecular sieve is tested by continuous rotation electron diffraction (cRED), and the crystallographic structure file (CIF file) is obtained. The structure analysis results show that the crystal structure of the mesoporous silicate molecular sieves provided by Examples 1-3 all belong to the trigonal system and are P-3 space group. ​​

[0114] The unit cell parameters of the mesoporous silicate molecular sieves provided in Examples 1-3 were obtained from powder X-ray diffraction data: a = b = 90°, g = 120°.

[0115] The chemical composition of the mesoporous silicate molecular sieves provided in Examples 1-3 was calculated from the crystallographic structure file to be SiO 2.079 .

[0116] The crystal structure of the mesoporous silicate molecular sieves provided in Examples 1-3 is shown in Figure 3 , Figure 4 and Figure 5 .

[0117] As can be seen from Figures 3 to 5 , in the c-axis direction of the crystal structure of the mesoporous silicate molecular sieves provided in Examples 1-3, there are through 36-membered ring channels, while there are no openings of more than 8-membered rings in other directions. Therefore, the structure is described as a 36-membered ring one-dimensional mesoporous channel system.

[0118] As can be seen from the crystallographic structure file, the mesoporous silicate molecular sieves provided in Examples 1-3 have a minimum size of the pore opening of more than 2 nm, and the crystal structure is long-range ordered at the atomic scale.

[0119] 5. Topological analysis was performed using the crystallographic structure file (CIF file) obtained after cRED testing. The topological analysis software was based on ToposPro 5.3.0.2, and the analysis process and method were based on the operation manual given on the official website of the software (see ToposPro website: https: / / topospro.com / software / ).

[0120] The analysis results showed that the mesoporous silicate molecular sieves provided in Examples 1-3 had 14 topologically independent T atoms in the framework, and the specific topological characteristics are shown in the following table:

[0121]

[0122]

[0123] The above description is merely a specific implementation of the present disclosure, which enables those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A mesoporous silicate molecular sieve characterized by, The mesoporous silicate molecular sieve has the following X-ray powder diffraction characteristics:

2. The mesoporous silicate molecular sieve of claim 1, wherein, The mesoporous silicate molecular sieve has a one-dimensional mesoporous pore system with 36-membered rings in the crystal structure.

3. The mesoporous silicate molecular sieve of claim 1 or 2, wherein, The framework of the mesoporous silicate molecular sieve has 14 topologically independent T atoms, and the topological characteristics are as follows: T represents a Si atom; Preferably, the mesoporous silicate molecular sieve has a chemical composition of SiO 2.079 .

4. A process for the preparation of the mesoporous silicate molecular sieve of any one of claims 1 to 3, characterized in that, The preparation method comprises the following steps: (1) mixing a silicon source, an organic template agent and water, aging under alkaline conditions, removing excess solvent to obtain a gel; (2) crystallizing the gel to obtain a crystallization product; (3) calcining the crystallization product to remove the organic template agent to obtain the mesoporous silicate molecular sieve; The cation of the organic template agent is selected from one or more of the cations having the structures shown in the following general formula: R1 and R2 are adamantyl groups; R3 is a methyl group, an ethyl group, a propyl group or a butyl group, preferably an ethyl group or a butyl group, more preferably an ethyl group; X is phosphorus or nitrogen, preferably phosphorus; n represents the number of methylene groups, and is an integer of 2-16, preferably an integer of 6-12, more preferably an integer of 10-12.

5. The preparation method according to claim 4, characterized in that, The cation of the organic template agent is selected from one or more of the following cations: Preferably, the cation of the organic template agent is selected from one or more of the following cations: More preferably, the cation of the organic template agent is selected from one or more of the following cations: Preferably, the anion of the organic template is selected from one or more of OH - , CI - , Br - , and I - , preferably OH - .

6. The production method according to claim 4 or 5, characterized by, The chemical composition of the gel is SiO2:rROH:wH2O; R represents the cation of the organic template agent, r = 0.05-1, and w = 1-100; preferably r = 0.05-0.5, and w = 1-10; Preferably, the silicon source is selected from one or more of silicic acid, silica gel, silica sol, tetraalkyl silicate and water-soluble silicate.

7. The method of any one of claims 4-6, wherein, Seeds are further added in the mixing step in step (1), and the seeds are the crystallization product in step (2) and / or the mesoporous silicate molecular sieve according to any one of claims 1-3; Preferably, the mass content of the seeds in the gel is 0.01-10000 ppm.

8. The method of any one of claims 4-7, wherein, The aging method is stirring at a temperature of 15-30°C for 2-24 h; Preferably, the crystallization temperature is 80-240°C, preferably 80-220°C, more preferably 100-190°C; Preferably, the crystallization time is 1-60 days, preferably 1-45 days, more preferably 1-30 days; Preferably, the preparation method further comprises washing and drying the obtained product after the crystallization; Preferably, the calcination temperature is 400-650°C, and the time is 2-6 h; Preferably, the atmosphere during the calcination is air, oxygen, hydrogen, nitrogen or an inert element gas; Preferably, the atmosphere during the calcination is air or oxygen, and the preparation method further comprises washing and drying the obtained product after the calcination.

9. A molecular sieve composition characterized by, The molecular sieve composition comprises the mesoporous silicate molecular sieve according to any one of claims 1-3 or prepared by the preparation method according to any one of claims 4-8, and a binder.

10. Use of a mesoporous silicate molecular sieve according to any one of claims 1 to 3, a mesoporous silicate molecular sieve produced according to the method of any one of claims 4 to 8 or a molecular sieve composition according to claim 9 as a catalyst or adsorbent.

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