Method for synthesizing mesitylene through isomerization of unsym-trimethylbenzene

Abstract

According to the method, a heteroatom EWT structure molecular sieve with a framework containing aluminum atoms and heteroatoms is adopted as a catalyst, the molecular sieve has the advantage of improving the utilization rate of an acid center, and when the molecular sieve is used for a gas-phase non-hydroisomerization reaction of the unsym-trimethylbenzene, the utilization rate of the acid center is increased; according to the present invention, the activity, the selectivity and the stability are high, the catalytic performance is significantly improved, the mesitylene selectivity and the mesitylene yield are higher than the heteroatom-free [Si, Al]-EWT structure molecular sieve, and the by-products such as tetratoluene and xylene are significantly reduced.

Description

Technical Field

[0001] This disclosure relates to the field of petrochemical technology, and more specifically, to a method for isomerizing trimesyl toluene to synthesize mesitylene. Background Technology

[0002] Mesitylene, chemically known as 1,3,5-trimethylbenzene, is a valuable fine chemical raw material with a wide range of applications. Its main use is in the production of mesityleneamine, an intermediate in the synthesis of the dyes Reactive Brilliant Blue K-3R and Praslan RAW. It can also be used to synthesize wheat herbicides, antioxidants, pharmaceuticals, and other chemical products and intermediates. In recent years, the development of downstream products of mesitylene has boosted its domestic demand, thus indicating a promising market prospect.

[0003] Currently, the more mature and promising methods for producing mesitylene reported in domestic and international research mainly include the following: isomerization of mesitylene, distillation separation of heavy aromatics, extractive distillation, molecular sieve adsorption separation, complexation separation, alkylation separation, and atmospheric pressure liquid-phase alkylation of mesitylene.

[0004] Isomerization of pseudotrimethylbenzene is one of the main methods for producing mesitylene. Zhang Weijiang et al. conducted research on isomerization reactions using aluminum trichloride as a catalyst. However, aluminum trichloride is easily hydrolyzed to generate hydrochloric acid, causing severe corrosion to the equipment. Zhang Pengfei et al. used a solid acid catalyst to study the liquid-phase isomerization of pseudotrimethylbenzene to prepare mesitylene under pressure. This study solved the problem of o-ethylbenzene accumulation during the reaction, but no reports of its industrial production have been found.

[0005] To improve catalyst stability, it is necessary to add metal components that inhibit coking and operate under hydrogen-exposed conditions. However, the aforementioned hydrogen-exposed operation is complex, has harsh operating conditions, high equipment requirements, large investment, is limited by hydrogen sources, has poor adaptability, leads to the accumulation of o-toluene, and results in the trimethylbenzene product failing to meet quality requirements. Furthermore, the energy consumption is high and the reaction is highly dangerous when carried out under gas-phase conditions. Summary of the Invention

[0006] The purpose of this disclosure is to provide a method for synthesizing mesitylene by isomerization of pseudotrimethylbenzene. This method uses a heteroatom EWT structure molecular sieve containing aluminum atoms and heteroatoms in its framework as a catalyst. This molecular sieve has advantages in improving the utilization rate of acid centers. When used in the gas-phase non-hydroisomerization reaction of pseudotrimethylbenzene, it has high activity, selectivity and stability, and the catalytic performance is significantly improved. The selectivity and yield of mesitylene are higher than those of the [Si,Al]-EWT structure molecular sieve without heteroatoms, while the byproducts such as tetramethylbenzene and xylene are significantly reduced.

[0007] To achieve the above objectives, this disclosure provides a method for isomerizing pseudotrimethylbenzene to synthesize mesitylene. The method includes: contacting pseudotrimethylbenzene with a catalyst under gas-phase non-hydroisomerization reaction conditions; wherein the catalyst is a heteroatom EWT structured molecular sieve, the framework of which contains silicon, aluminum, and heteroatoms, and the molar ratio of silicon (calculated as SiO2) to aluminum (calculated as Al2O3) in the heteroatom EWT structured molecular sieve is 30 or more. The molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the molecular sieve is 30 or more; the heteroatom elements include one or more of boron, iron, titanium, gallium, and germanium; the total acid content of the heteroatom EWT structure molecular sieve, as measured by the NH3-TPD method, is 700–790 μmol / g, the Brønsted acid content, as measured by the pyridine adsorption infrared method at 350℃, is 15–60 μmol / g, the Lewis acid content is 65–140 μmol / g, and the ratio of Brønsted acid content to Lewis acid content is 0.25–0.7.

[0008] Optionally, the conditions for the gas-phase non-hydroisomerization reaction include: contacting the catalyst with p-xylene under a nitrogen atmosphere, wherein the nitrogen flow rate is 10–20 mL / min, preferably 14–18 mL / min; the contact temperature is 240–450 °C, preferably 280–360 °C; the contact time is 10–500 h, preferably 20–350 h; and the pressure is 0.1–2.0 MPa, preferably 0.5–1.5 MPa. Preferably, the reaction is carried out in a fixed-bed reactor, and the mass hourly space velocity (WHSV) of the p-xylene is 0.5–3.5 h⁻¹. -1 Preferably, it is 0.5 to 1.5 hours. -1 .

[0009] Optionally, the molar ratio of silicon (calculated as SiO2) to aluminum (calculated as Al2O3) in the heteroatom EWT structure molecular sieve is 35–180, preferably 40–120; the molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the heteroatom EWT structure molecular sieve is 30–220.

[0010] Optionally, when the heteroatom element is boron, the molar ratio of silicon (calculated as SiO2) to boron (calculated as B2O3) in the heteroatom EWT structure molecular sieve is 120–180, preferably 150–180; when the heteroatom element is one or more of iron, titanium, gallium, and germanium, the molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the heteroatom EWT structure molecular sieve is 120–220, preferably 150–200.

[0011] Optionally, the total acid content of the heteroatom EWT structured molecular sieve, as determined by the NH3-TPD method, is 750–790 μmol / g; the Brønsted acid content, as determined by pyridine adsorption infrared spectroscopy at 350 °C, is 30–55 μmol / g; the Lewis acid content is 70–138 μmol / g; and the ratio of Brønsted acid content to Lewis acid content is 0.4–0.68. The total specific surface area of ​​the heteroatom EWT structured molecular sieve is 500–680 m² / g. 2 / g, preferably 540-650m 2 / g; average pore size is 0.5–20 nm, preferably 2–5 nm; total pore volume is 0.25–0.60 cm³. 3 / g, preferably 0.30~0.55cm 3 / g; the volume of mesopores with a pore size of 2.0–20.0 nm is 0.05–0.35 cm³. 3 / g, preferably 0.10~0.25cm 3 / g; the mesopore volume with a pore size of 2.0 to 20.0 nm accounts for 30 to 80% of the total pore volume, preferably 35 to 70%; the average particle size of the heteroatom EWT structure molecular sieve is 0.2 to 1.5 μm, preferably 0.3 to 1.0 μm; the relative crystallinity is 50 to 100%, preferably 65 to 90%; preferably, the heteroatom EWT structure molecular sieve is a hydrogen-type heteroatom EWT structure molecular sieve.

[0012] Optionally, the method further includes preparing the catalyst using the following steps:

[0013] (1) A silicon source, a heteroatom element source, a first alkali source, a first organic template agent and water are mixed, and the resulting first material to be crystallized is subjected to a first crystallization to obtain molecular sieve raw powder; the molecular sieve raw powder is calcined to obtain sodium-type molecular sieve;

[0014] (2) The sodium molecular sieve is subjected to ion exchange with an acid solution, the obtained molecular sieve intermediate is mixed with an aluminum source, a second alkali source and a second organic template agent, and the obtained second crystallization material is subjected to a second crystallization.

[0015] The heteroatom elements include one or more of boron, iron, titanium, gallium, and germanium; the first organic template agent and the second organic template agent are respectively a cyclic bis-quaternary ammonium base compound and / or a cyclic bis-quaternary ammonium salt compound; the temperature of the first crystallization is 60–180°C, preferably 100–170°C; the time is 96–168 h, preferably 96–144 h; the temperature of the second crystallization is 60–180°C, preferably 100–170°C; the time is 96–168 h, preferably 96–144 h.

[0016] Optionally, the silicon source is selected from one or more of silica sol, water glass, solid silica gel, tetraethyl orthosilicate, and fumed silica, preferably solid silica gel; the heteroatom element source is selected from one or more of boron oxide, iron oxide, titanium oxide, gallium oxide, and germanium oxide, preferably boron oxide; the first alkali source and the second alkali source are respectively selected from one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide, preferably both of the first alkali source and the second alkali source are sodium hydroxide; the aluminum source is selected from one or more of aluminum chloride, aluminum sulfate, hydrated alumina, sodium aluminate, and aluminum sol, preferably sodium aluminate; the first organic template agent and the second organic template agent are respectively selected from at least one having the structure shown in formula (1):

[0017]

[0018] R1, R2, R3, and R4 are each independently selected from alkyl groups having 1 to 4 carbon atoms. Preferably, R1, R2, R3, and R4 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl, preferably methyl or ethyl; m is 2 or 3; n is any integer from 1 to 10; X - This includes hydroxide ions or halide anions.

[0019] Optionally, the silicon source is SiO2, and the heteroatom element source is heteroatom oxide. When the heteroatom element is boron, the molar ratio of SiO2 to B2O3 in the first material to be crystallized is 30 to 180, preferably 60 to 150. When the heteroatom element is one or more of iron, titanium, gallium, and germanium, the molar ratio of SiO2 to heteroatom oxide in the first material to be crystallized is 30 to 210, preferably 60 to 180.

[0020] Optionally, in step (1), the silicon source is SiO2, the heteroatom element source is heteroatom oxide, the first organic template agent is T1, and when the heteroatom element in the first material to be crystallized is boron, the molar ratio of SiO2 to B2O3 is 30-210, preferably 60-180; when the heteroatom element is one or more of iron, titanium, gallium and germanium, the molar ratio of SiO2 to heteroatom oxide is 30-210, preferably 30-150; and when the heteroatom element is OH... - The molar ratio of the first alkali source to SiO2 is 0-1.0, preferably 0.1-0.3; the molar ratio of T1 to SiO2 is 0.02-0.5, preferably 0.08-0.15; the molar ratio of H2O to SiO2 is 5-20, preferably 5-10; in step (2), the aluminum source is Al2O3, the second organic template agent is T2, and the molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 30 or more, preferably 30-180, more preferably 45-150; the OH-- The molar ratio of the second alkali source to SiO2 is 0.2 to 1.0, preferably 0.2 to 0.5; the molar ratio of T2 to SiO2 is 0.02 to 0.5, preferably 0.08 to 0.15; and the molar ratio of H2O to SiO2 is 5 to 20, preferably 5 to 10.

[0021] Optionally, in step (1), the calcination temperature is 400–650°C and the time is 1–7 h; in step (2), the weight ratio of the acid solution to the sodium molecular sieve is (1–100):1, the concentration of the acid solution is 0.01–0.10 mol / L, the ion exchange temperature is 60–90°C, and the time is 2–24 h; the acid solution is selected from one or more of hydrochloric acid, nitric acid, and sulfuric acid.

[0022] This disclosure provides a method for synthesizing mesitylene via the isomerization of pseudotrimethylbenzene. This method utilizes a heteroatom-EWT structured molecular sieve with aluminum and heteroatoms in its framework as a catalyst. This heteroatom-EWT molecular sieve possesses a 3D channel system composed of 21-membered and 10-membered rings, exhibiting a suitable distribution of acidic centers and demonstrating advantages in improving the utilization rate of acidic centers. Furthermore, the aluminum atoms in the framework of this heteroatom-EWT molecular sieve can adjust the acidity of the sieve, while the heteroatoms can adjust the position of the aluminum atoms and the acid type, making the acidity of the molecular sieve more suitable. When this heteroatom-EWT molecular sieve is used in the gas-phase non-hydroisomerization reaction of pseudotrimethylbenzene, its activity, selectivity, and stability are all high, and its catalytic performance is significantly improved. The selectivity and yield of mesitylene are both higher than those of [Si,Al]-EWT molecular sieves without heteroatoms, and byproducts such as tetramethylbenzene and xylene are significantly reduced. This disclosure employs a two-stage crystallization method of crystallization-decomposition-dissolution-recrystallization. First, EWT structured molecular sieves containing silicon and heteroatoms are prepared. Then, some framework heteroatoms are removed to form silanol nests, providing vacancy sites to facilitate Al atoms entering the framework to complete isomorphous substitution, thereby preparing molecular sieves with a lower silicon-to-aluminum ratio. At the same time, the acidity of the molecular sieve is improved to meet the requirements of acidic catalytic reactions.

[0023] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is the XRD pattern of the [B,Al]-EWT structured molecular sieve prepared in Example 1 of this disclosure;

[0026] Figure 2 This is a SEM image of the [B,Al]-EWT structured molecular sieve prepared in Example 1 of this disclosure;

[0027] Figure 3 This is a TEM image of the [B,Al]-EWT structured molecular sieve prepared in Example 1 of this disclosure;

[0028] Figure 4 This is an isotherm curve of the [B,Al]-EWT structured molecular sieve prepared in Example 1 of this disclosure. Detailed Implementation

[0029] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0030] This disclosure provides a method for isomerizing pseudotrimethylbenzene to synthesize mesitylene. The method includes: contacting pseudotrimethylbenzene with a catalyst under gas-phase non-hydroisomerization reaction conditions; wherein the catalyst is a heteroatom EWT structure molecular sieve, the framework of which contains silicon, aluminum, and heteroatom elements, the molar ratio of silicon (based on SiO2) to aluminum (based on Al2O3) in the heteroatom EWT structure molecular sieve is 30 or more, and the molar ratio of silicon (based on SiO2) to aluminum (based on Al2O3) in the heteroatom EWT structure molecular sieve is 30 or more. The molar ratio of silicon (based on iO2) to heteroatom elements (based on heteroatom oxides) is 30 or more; the heteroatom elements include one or more of boron, iron, titanium, gallium, and germanium; the total acid content of the heteroatom EWT structure molecular sieve, as determined by the NH3-TPD method, is 700–790 μmol / g, the Brønsted acid content, as determined by pyridine adsorption infrared spectroscopy at 350 °C, is 15–60 μmol / g, the Lewis acid content is 65–140 μmol / g, and the ratio of Brønsted acid content to Lewis acid content is 0.25–0.7.

[0031] The method for synthesizing mesitylene by isomerization of pseudotrimethylbenzene disclosed herein uses a heteroatom-EWT structured molecular sieve containing aluminum atoms and heteroatoms in its framework as a catalyst. This heteroatom-EWT structured molecular sieve has a 3D channel system composed of 21-membered and 10-membered rings, exhibiting a suitable distribution of acidic centers, which can significantly improve the utilization rate of the acidic centers in the molecular sieve. Furthermore, the aluminum atoms in the molecular sieve framework can adjust the acidity of the molecular sieve, while the heteroatoms can adjust the position of the aluminum atoms and the acid distribution, thus making its acidity more suitable. When this heteroatom-EWT structured molecular sieve is used in the gas-phase non-hydroisomerization reaction of pseudotrimethylbenzene, it exhibits high activity, selectivity, and stability, with significantly improved catalytic performance. The selectivity and yield of mesitylene are higher than those of [Si,Al]-EWT structured molecular sieves without heteroatoms, and byproducts such as tetramethylbenzene and xylene are significantly reduced.

[0032] In one embodiment of this disclosure, the conditions for the gas-phase non-hydroisomerization reaction include: contacting the catalyst with pseudotrimethylbenzene under a nitrogen atmosphere, wherein the nitrogen flow rate is 10–20 mL / min, preferably 14–18 mL / min; the contact temperature is 240–450 °C, preferably 280–360 °C; the contact time is 10–500 h, preferably 20–350 h; and the pressure is 0.1–2.0 MPa, preferably 0.5–1.5 MPa. In a preferred embodiment, the reaction is carried out in a fixed-bed reactor, and the mass hourly space velocity (WHSV) of the pseudotrimethylbenzene is 0.5–3.5 h⁻¹. -1 Preferably, it is 0.5 to 1.5 hours. -1 In the above embodiments, by selecting preferred gas-phase non-hydroisomerization reaction conditions, it is beneficial for pseudotrimethylbenzene to fully contact with the catalyst, thereby further improving the conversion rate of pseudotrimethylbenzene and the product selectivity.

[0033] In one embodiment of this disclosure, the molar ratio of silicon (calculated as SiO2) to aluminum (calculated as Al2O3) in the heteroatom EWT structured molecular sieve is 35–180, preferably 40–120; the molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the heteroatom EWT structured molecular sieve is 30–220. In the above embodiment, by selecting preferred silicon-to-aluminum ratios and silicon-to-heteroatom ratios, the acid distribution and acid strength of the molecular sieve can be further adjusted, thereby improving the catalytic activity of the molecular sieve.

[0034] In one embodiment of this disclosure, when the heteroatom element is boron, the molar ratio of silicon (calculated as SiO2) to boron (calculated as B2O3) in the heteroatom EWT structure molecular sieve is 120–180, preferably 150–180; when the heteroatom element is one or more of iron, titanium, gallium, and germanium, the molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the heteroatom EWT structure molecular sieve is 120–220, preferably 150–200.

[0035] In one embodiment of this disclosure, the total acid content of the heteroatom EWT structured molecular sieve, as measured by the NH3-TPD method, is 750–790 μmol / g; the Brønsted acid content, as measured by pyridine adsorption infrared spectroscopy at 350°C, is 30–55 μmol / g; the Lewis acid content is 70–138 μmol / g; and the ratio of Brønsted acid content to Lewis acid content is 0.4–0.68. In the above embodiment, selecting a molecular sieve with optimal acid strength is beneficial for improving the catalytic activity and selectivity of the molecular sieve.

[0036] In another embodiment, the total specific surface area of ​​the heteroatom EWT structured molecular sieve is 500–680 m². 2 / g, preferably 540-650m2 / g; average pore size is 0.5–20 nm, preferably 2–5 nm; total pore volume is 0.25–0.60 cm³. 3 / g, preferably 0.30~0.55cm 3 / g; the volume of mesopores with a pore size of 2.0–20.0 nm is 0.05–0.35 cm³. 3 / g, preferably 0.10~0.25cm 3 / g; the mesopore volume with a pore size of 2.0–20.0 nm accounts for 30–80% of the total pore volume, preferably 35–70%; the average particle size of the heteroatom EWT structure molecular sieve is 0.2–1.5 μm, preferably 0.3–1.0 μm; the relative crystallinity is 50–100%, preferably 65–90%; preferably, the heteroatom EWT structure molecular sieve is a hydrogen-type heteroatom EWT structure molecular sieve. In the above embodiments, the heteroatom EWT structure molecular sieve has a rich pore structure, which is beneficial for catalyzing the isomerization reaction of pseudotrimethylbenzene and improving the selectivity of mesitylene.

[0037] In one embodiment of this disclosure, the method further includes preparing the catalyst by the following steps:

[0038] (1) A silicon source, a heteroatom element source, a first alkali source, a first organic template agent and water are mixed, and the resulting first material to be crystallized is subjected to a first crystallization to obtain molecular sieve raw powder; the molecular sieve raw powder is calcined to obtain sodium-type molecular sieve;

[0039] (2) The sodium molecular sieve is subjected to ion exchange with an acid solution, the obtained molecular sieve intermediate is mixed with an aluminum source, a second alkali source and a second organic template agent, and the obtained second crystallization material is subjected to a second crystallization.

[0040] The heteroatom element includes one or more of boron, iron, titanium, gallium, and germanium. The first organic template agent and the second organic template agent are respectively a cyclic bis-quaternary ammonium base compound and / or a cyclic bis-quaternary ammonium salt compound. The temperature of the first crystallization is 60–180°C, preferably 100–170°C; the time is 96–168 h, preferably 96–144 h. The temperature of the second crystallization is 60–180°C, preferably 100–170°C; the time is 96–168 h, preferably 96–144 h. A cyclic bis-quaternary ammonium base compound refers to a cyclic compound containing two quaternary ammonium bases, and the nitrogen atoms of the two quaternary ammonium bases are not directly connected. A cyclic bis-quaternary ammonium salt compound refers to a cyclic compound containing two quaternary ammonium salts, and the nitrogen atoms of the two quaternary ammonium salts are not directly connected.

[0041] In the above embodiments, an EWT-structured molecular sieve containing silicon and heteroatoms is first prepared by employing a secondary crystallization method of crystallization-decomposition-dissolution-recrystallization. Then, some framework heteroatoms are removed to form silanol nests, providing vacancy sites to facilitate the entry of Al atoms into the framework for isomorphous substitution, thereby preparing a molecular sieve with a lower silicon-to-aluminum ratio. This improves the acidity of the molecular sieve and meets the requirements of acidic catalytic reactions. The method disclosed herein can synthesize ultra-large porous molecular sieves with a 3D channel system composed of 21-membered and 10-membered rings, effectively improving the pore structure of the molecular sieve. This allows for the introduction of larger aluminum atoms and heteroatoms into the molecular sieve framework, optimizing the acid distribution and acid strength of the molecular sieve, and obtaining higher selectivity and yield for mesitylene.

[0042] In one embodiment of this disclosure, the silicon source is selected from one or more of silica sol, water glass, solid silica gel, tetraethyl orthosilicate, and silica, preferably solid silica gel; the heteroatom element source is selected from one or more of boron oxide, iron oxide, titanium oxide, gallium oxide, and germanium oxide, preferably boron oxide; the first alkali source and the second alkali source are respectively selected from one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide, preferably both of the first and second alkali sources are sodium hydroxide; the aluminum source is selected from one or more of aluminum chloride, aluminum sulfate, hydrated alumina, sodium aluminate, and aluminum sol, preferably sodium aluminate; the first organic template agent and the second organic template agent are respectively selected from at least one having the structure shown in formula (1): R1, R2, R3, and R4 are each independently selected from alkyl groups having 1 to 4 carbon atoms. Preferably, R1, R2, R3, and R4 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl, preferably methyl or ethyl; m is 2 or 3; n is any integer from 1 to 10; X - This includes hydroxide ions or halide anions.

[0043] In one embodiment of this disclosure, the silicon source is SiO2, and the heteroatom element source is heteroatom oxide. When the heteroatom element is boron, the molar ratio of SiO2 to B2O3 in the first material to be crystallized is 30 to 180, preferably 60 to 150. When the heteroatom element is one or more of iron, titanium, gallium, and germanium, the molar ratio of SiO2 to heteroatom oxide in the first material to be crystallized is 30 to 210, preferably 60 to 180.

[0044] In one embodiment of this disclosure, in step (1), the silicon source is SiO2, the heteroatom element source is heteroatom oxide, the first organic template agent is T1, and when the heteroatom element in the first material to be crystallized is boron, the molar ratio of SiO2 to B2O3 is 30-210, preferably 60-180; when the heteroatom element is one or more of iron, titanium, gallium, and germanium, the molar ratio of SiO2 to heteroatom oxide is 30-210, preferably 30-150; and when the heteroatom element is OH... - The molar ratio of the first alkali source to SiO2 is 0-1.0, preferably 0.1-0.3; the molar ratio of T1 to SiO2 is 0.02-0.5, preferably 0.08-0.15; the molar ratio of H2O to SiO2 is 5-20, preferably 5-10; in step (2), the aluminum source is Al2O3, the second organic template agent is T2, and the molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 30 or more, preferably 30-180, more preferably 45-150; the OH- - The molar ratio of the second alkali source to SiO2 is 0.2 to 1.0, preferably 0.2 to 0.5; the molar ratio of T2 to SiO2 is 0.02 to 0.5, preferably 0.08 to 0.15; and the molar ratio of H2O to SiO2 is 5 to 20, preferably 5 to 10.

[0045] In one embodiment of this disclosure, in step (1), the calcination temperature is 400–650°C and the time is 1–7 h; in step (2), the weight ratio of the acid solution to the sodium molecular sieve is (1–100):1, the concentration of the acid solution is 0.01–0.10 mol / L, the ion exchange temperature is 60–90°C, and the time is 2–24 h; the acid solution is selected from one or more of hydrochloric acid, nitric acid, and sulfuric acid.

[0046] The present invention will be further illustrated by the following examples, but this disclosure is not limited thereto.

[0047] In the embodiments and comparative examples of this disclosure, a Quanta 200F scanning electron microscope (SEM) from FEI Corporation was used for microscopic morphology analysis, with the working voltage of the SEM being 20 kV; the average particle size of the catalyst was measured using a Japan Hitachi S-4800type instrument.

[0048] The crystallinity of the molecular sieve was determined using the RIPP 146-90 standard method. For details of the RIPP standard method mentioned here, please refer to "Analytical Methods for Petrochemical Products", edited by Yang Cuiding et al., 1990 edition.

[0049] The chemical composition of the molecular sieve was determined using a Rigaku Electric Co., Ltd. 3013 X-ray fluorescence spectrometer. The silicon-to-aluminum ratio and silicon-to-heteroatom ratio of the molecular sieve were calculated. A tungsten target was used, with an excitation voltage of 40 kV and an excitation current of 50 mA.

[0050] Total specific surface area, total pore volume, and mesopore volume were measured using the nitrogen adsorption BET specific surface area method, employing an AS-3 or AS-6 static nitrogen adsorption instrument manufactured by Quantachrome Instruments. The specific method involved placing the sample in the sample processing system and evacuating it to a vacuum of 1.33 × 10⁻⁶ at 300°C. -2 The sample was purified by holding it at a pressure of 4 h under the pressure of liquid nitrogen. The adsorption and desorption of nitrogen on the purified sample under different specific pressures P / P0 were tested at a liquid nitrogen temperature of -196℃. The N2 adsorption-desorption isotherm curves were obtained, and then the total specific surface area, total pore volume and mesopore volume were calculated using the two-parameter BET formula.

[0051] Total acid content was measured using the NH3-TPD method with an Autochem II 2920 temperature-programmed desorption instrument from Micron Technology, USA. The specific method was as follows: 0.2 g of the sample to be tested was weighed and placed in a sample tube, which was then placed in a thermal conductivity cell furnace. He gas was used as the carrier gas (50 mL / min), and the temperature was increased to 600 °C at a rate of 20 °C / min. The sample was purged for 60 min to remove impurities adsorbed on the catalyst surface. The temperature was then reduced to 100 °C and held for 30 min. The sample was then switched to an NH3-He mixed gas (10.02% NH3 + 89.98% He) for adsorption for 30 min. The sample was then purged with He gas for another 90 min until the baseline stabilized to desorb the physically adsorbed ammonia. The temperature was increased to 600 °C at a rate of 10 °C / min and held for 30 min to complete the desorption. The gas composition changes were detected using a TCD detector, and the total acid content was obtained by automatic integration of the results.

[0052] The acid content of Brønsted (B) and Lewis (L) acids was measured using the 2,6-di-tert-butylpyridine adsorption infrared spectroscopy method, employing a Vertex 70 instrument manufactured by Bruker Instruments. The specific method involved pressing the catalyst to a concentration of 10 mg / cm³. 2 Thin slices were placed in an infrared cell with a CaF2 window. The cell was first evacuated to 400°C, then cooled to 150°C to adsorb 2,6-di-tert-butylpyridine for 15 minutes. After evacuation for 1 hour, the cell was cooled to room temperature, and spectra were collected. The amounts of Brønsted acid and Lewis acid were calculated. See Applied Catalysis A: General, 294, 2005: 92.

[0053] The conversion rate of pseudotrimethylbenzene, the selectivity of mesitylene, and the selectivity of byproducts were calculated using the gas chromatography peak area normalization method. The specific testing method was as follows: nitrogen as the carrier gas, FID detector, column temperature 80℃, injector temperature 260℃, and detector temperature 250℃. The programmed temperature was 0℃ initially, held for 0 min at a rate of 3℃ / min, and reached a final temperature of 50℃ with a holding time of 20 min. The injection volume was 0.2 μL.

[0054] Preparation Example 1

[0055] (1) Add an aqueous solution containing 0.01425 mol of the first organic template agent (denoted as T1, with the structure as follows) to the polytetrafluoroethylene liner. Where m = 2, n = 3, R1, R2, R3 and R4 are all methyl groups, T1 has a molar mass of 248 g / mol and a mass fraction of 25.74%), and 0.00212 mol of boric acid; then add 0.02 mol of sodium hydroxide (the first alkali source) and 0.051 mol of water, and finally add 0.095 mol of coarse solid silica gel, stir evenly, and obtain the first material to be crystallized, wherein the molar ratio of SiO2 to B2O3 in the first material to be crystallized is 90, with OH... - The molar ratio of the first alkali source to SiO2 was 0.21, the molar ratio of T1 to SiO2 was 0.15, and the molar ratio of H2O to SiO2 was 6.5. The polytetrafluoroethylene-lined cap was sealed, and the mixture was placed in a stainless steel crystallization autoclave. The autoclave was then placed in a rotary oven, and the crystallization temperature program was set. The first crystallization was initiated at 160℃ for 144 hours. After the first crystallization, the autoclave was allowed to cool to room temperature. The autoclave was then opened, and the product was washed and filtered with deionized water. Finally, it was dried in an oven at 80℃ for 12 hours. The resulting molecular sieve powder was then calcined in a muffle furnace at 550℃ for 5 hours to remove the template agent, yielding a boron-containing sodium-type molecular sieve.

[0056] (2) Ion exchange of sodium molecular sieve with hydrochloric acid solution is carried out as follows: hydrochloric acid solution and sodium molecular sieve are mixed at a weight ratio of 40:1, heated to 80°C under stirring and reflux conditions, and kept for 12 hours (i.e., the temperature of ion exchange is 80°C and the time is 12 hours). After washing, filtering and drying, molecular sieve intermediate is obtained; the concentration of hydrochloric acid solution is 0.03 mol / L. Add the following to a polytetrafluoroethylene (PTFE) liner: an aqueous solution containing 0.01425 mol of a second organic template agent (denoted as T2, T2 having the same structure as T1, with a molar mass of 248 g / mol and a mass fraction of 25.74%), 1.72 mL of sodium aluminate (containing 101.5 g / L alumina, 194 g / L sodium hydroxide, 150.35 g / L sodium oxide, with a specific gravity of 1.227 g / mL and a mass fraction of 20.50%), 0.02 mol of sodium hydroxide (a second alkali source), and 0.198 mol of water. Then add a molecular sieve intermediate and stir the resulting second crystallization material evenly. The molar ratio of SiO2 to Al2O3 in the second crystallization material is 5:6. - The molar ratio of the second alkali source to SiO2 was 0.30, the molar ratio of T2 to SiO2 was 0.15, and the molar ratio of H2O to SiO2 was 9.0. Finally, the polytetrafluoroethylene liner was sealed and placed in a stainless steel crystallization kettle, which was then placed in a rotary oven for a second crystallization at 160℃ for 144h. This yielded a molecular sieve with a [B,Al]-EWT structure containing aluminum and boron atoms in its framework, namely catalyst 1, denoted as C1. Its physicochemical properties are shown in Tables 1-2.

[0057] The XRD pattern of the prepared catalyst C1 is as follows: Figure 1 As shown, the SEM image is as follows: Figure 2 As shown, the TEM image is as follows Figure 3 As shown, the isotherm curve is as follows: Figure 4 As shown.

[0058] Among them, from Figure 1 It can be seen that the XRD pattern of C1 shows peaks near 2θ = 5.1°, 8.2°, and 8.9°, indicating that catalyst C1 is an EWT structure molecular sieve with a relative crystallinity of 70%. Figure 2 It can be seen that the average particle size of C1 is 0.4–0.8 μm; from Figure 3 It can be seen that C1 has a layered nanosheet morphology and a large specific surface area; from Figure 4 It can be seen that C1 has a porous structure.

[0059] Preparation Example 2

[0060] The preparation method is the same as in Example 1, except that: iron oxide is used instead of boric acid; the molar ratio of SiO2 to Fe2O3 in the first material to be crystallized is 80; the temperature of the first crystallization is 160℃ and the time is 96h; the molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 45; the temperature of the second crystallization is 165℃ and the time is 120h, thus obtaining a [Fe,Al]-EWT structure molecular sieve with an aluminum and iron atom framework, namely catalyst 2, denoted as C2.

[0061] The XRD pattern of C2 shows peaks near 2θ = 5.1°, 8.2°, and 8.9°, indicating that catalyst C2 is an EWT structure molecular sieve.

[0062] Preparation Example 3

[0063] The preparation method is the same as in Example 1, except that titanium oxide is used instead of boric acid. The molar ratio of SiO2 to TiO2 in the first material to be crystallized is 100, the temperature of the first crystallization is 140℃, and the time is 144h. The molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 50, the temperature of the second crystallization is 175℃, and the time is 96h. A [Ti,Al]-EWT structure molecular sieve with aluminum and titanium atoms in its framework is obtained, namely catalyst 3, denoted as C3.

[0064] The XRD pattern of C3 shows peaks near 2θ = 5.1°, 8.2°, and 8.9°, indicating that catalyst C3 is an EWT structure molecular sieve.

[0065] Preparation Example 4

[0066] The preparation method is the same as in Example 1, except that gallium oxide is used instead of boric acid. The molar ratio of SiO2 to Ga2O3 in the first material to be crystallized is 90, the temperature of the first crystallization is 140℃, and the time is 148h. The molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 55, the temperature of the second crystallization is 165℃, and the time is 96h. A [Ga,Al]-EWT structure molecular sieve with aluminum and gallium atoms in its framework is obtained, namely catalyst 4, denoted as C4.

[0067] The XRD pattern of C4 shows peaks near 2θ = 5.1°, 8.2°, and 8.9°, indicating that catalyst C4 is an EWT structure molecular sieve.

[0068] Preparation Example 5

[0069] The preparation method is the same as in Example 1, except that germanium oxide is used instead of boric acid. The molar ratio of SiO2 to GeO2 in the first material to be crystallized is 100, the temperature of the first crystallization is 140℃, and the time is 48h. The molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 45, the temperature of the second crystallization is 175℃, and the time is 96h. A [Ge,Al]-EWT structure molecular sieve with aluminum and germanium atoms in the framework is obtained, namely catalyst 5, denoted as C5.

[0070] The XRD pattern of C5 shows peaks near 2θ = 5.1°, 8.2°, and 8.9°, indicating that catalyst C5 is an EWT structure molecular sieve.

[0071] Preparation Example 6

[0072] The preparation method is the same as in Example 1, except that the molar ratio of SiO2 to B2O3 in the first material to be crystallized is 90, and the molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 120, resulting in a [B,Al]-EWT molecular sieve with an aluminum and boron skeleton, namely catalyst 6, denoted as C6.

[0073] The XRD pattern of C6 shows peaks near 2θ = 5.1°, 8.2°, and 8.9°, indicating that catalyst C6 is an EWT structure molecular sieve.

[0074] Preparation Example 7

[0075] The preparation method was the same as in Example 1, except that the temperature of the first crystallization was 150°C and the time was 148 h. After the first crystallization, the crystallization vessel was cooled to room temperature, the vessel was opened, and the product was washed and filtered with deionized water. Finally, it was dried in an oven at 120°C for 24 h. The resulting molecular sieve powder was calcined in a muffle furnace at 580°C for 10 h to remove the template agent, thus obtaining a sodium-type molecular sieve. The temperature of the second crystallization was 170°C and the time was 96 h, resulting in a heteroatom EWT structure molecular sieve 7 with an aluminum and boron atom framework, i.e., catalyst 7, denoted as C7.

[0076] The XRD pattern of C7 shows peaks near 2θ = 5.1°, 8.2°, and 8.9°, indicating that catalyst C7 is an EWT structure molecular sieve.

[0077] Preparation of Comparative Example 1

[0078] (1) Sodium hydroxide (alkali source), sodium aluminate (aluminum source), and the structure as shown in formula (1) are added. An organic template agent (m=2, n=4, R1, R2, R3, and R4 are all methyl groups) is dissolved in water and mixed thoroughly to form a solution. Solid silica gel (silicon source) is added to the solution and mixed thoroughly to form a gel-like material to be crystallized. The molar ratios of the materials in the material to be crystallized are: n(SiO2) / n(Al2O3) = 60, n(T) / n(SiO2) = 0.15, n(OH) = 60, n(T) / n(SiO2) = 0.15, n(OH) = 60, n(T) / n(Al2O3 ... - ) / n(SiO2)=0.08, n(H2O) / n(SiO2)=10, where T is an organic template agent;

[0079] (2) The gel-like material to be crystallized was subjected to a crystallization reaction under autogenous pressure. The first stage of crystallization was carried out at a temperature of 120℃ for 24 hours, and then the temperature was raised to 160℃ for a second stage of crystallization under autogenous pressure for 120 hours. After crystallization, the material was filtered, washed and dried, and then subjected to ammonium exchange with an ammonium salt solution. After exchange, the material was filtered and dried, and then calcined at 550℃ for 4 hours to obtain a hydrogen-form EWT molecular sieve, which is the comparative catalyst 1, denoted as D1. Its physicochemical properties are shown in Tables 1-2.

[0080] Preparation of Comparative Example 2

[0081] ZSM-5 molecular sieve with n(SiO2) / n(Al2O3) = 40 (commercially purchased from Sinopec Changling Catalyst Plant) was subjected to ammonium exchange with ammonium salt. After filtration and drying, the exchanged material was calcined at 550℃ for 4 hours to obtain hydrogen-form ZSM-5 molecular sieve, which is the comparative catalyst 2, denoted as D2. Its physicochemical properties are shown in Tables 1-2.

[0082] Table 1

[0083]

[0084] Table 2

[0085]

[0086]

[0087] As can be seen from the data in Tables 1 and 2 above, the heteroatom EWT structure molecular sieve used in this disclosure has a low silica-alumina ratio, suitable acidity and acid strength, and a porous structure, which shows advantages in improving the utilization rate of acid centers and can improve the catalytic activity of the molecular sieve.

[0088] The following reaction examples illustrate the application of molecular sieves with different heteroatom EWT structures in the isomerization reaction of pseudotrimethylbenzene.

[0089] Example 1

[0090] A continuous flow pressurized fixed-bed reactor was loaded with 2g of C1 as a catalyst, and pseudotrimethylbenzene was added as a reactant. The reaction conditions were: temperature 300℃, pressure atmospheric pressure, nitrogen flow rate 16mL / min, and pseudotrimethylbenzene mass hourly space velocity (WHSV) 0.5h⁻¹. -1 The reaction time was 30 hours, and the evaluation results are shown in Table 3.

[0091] In the various embodiments and comparative examples:

[0092]

[0093]

[0094] Mesitylene yield = Metatrimethylbenzene conversion × Mesitylene selectivity × 100%

[0095]

[0096] Examples 2-7

[0097] Same as Example 1, except that C2 to C7 are used instead of C1 respectively, and the evaluation results are shown in Table 3.

[0098] Comparative Examples 1-2

[0099] Same as Example 1, except that D1 to D2 are used instead of C1 respectively, and the evaluation results are shown in Table 3.

[0100] Table 3

[0101]

[0102] As can be seen from the results in Table 3 above, the heteroatom EWT structure molecular sieve provided in this disclosure contains aluminum atoms and heteroatoms in its framework, giving the molecular sieve suitable acidity and acid strength. Furthermore, the 3D channel system composed of 21-membered and 10-membered rings in the heteroatom EWT structure molecular sieve can improve the utilization rate of acidic centers, resulting in high activity, selectivity, and stability. When used as a catalyst in the gas-phase non-hydroisomerization reaction of pseudotrimethylbenzene, it maintains high selectivity and yield of mesitylene, while significantly reducing byproducts such as tetramethylbenzene and xylene. In contrast, Comparative Examples 1 and 2, using EWT structure molecular sieves without heteroatoms in their framework as catalysts, exhibited lower selectivity for mesitylene and higher contents of byproducts such as tetramethylbenzene and xylene in the gas-phase non-hydroisomerization reaction of pseudotrimethylbenzene. Therefore, the heteroatom EWT structure molecular sieve provided in this disclosure has superior performance compared to the molecular sieves provided in the comparative examples.

[0103] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0105] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for isomerizing trimellitene to synthesize mesitylene, characterized in that, The method includes: contacting a catalyst with pseudotrimethylbenzene under gas-phase non-hydroisomerization reaction conditions; wherein the catalyst is a heteroatom EWT structure molecular sieve, the framework of which contains silicon, aluminum, and heteroatom elements, the molar ratio of silicon (calculated as SiO2) to aluminum (calculated as Al2O3) in the heteroatom EWT structure molecular sieve is 30 or more, and the molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the heteroatom EWT structure molecular sieve is 30 or more; the heteroatom elements include one or more of boron, iron, titanium, gallium, and germanium. The total acid content of the heteroatom EWT structured molecular sieve, as determined by the NH3-TPD method, was 700–790 μmol / g. The Brønsted acid content, as determined by the pyridine adsorption infrared method at 350 °C, was 15–60 μmol / g, and the Lewis acid content was 65–140 μmol / g. The ratio of Brønsted acid content to Lewis acid content was 0.25–0.

7.

2. The method according to claim 1, characterized in that, The conditions for the gas-phase non-hydroisomerization reaction include: contacting the catalyst with p-xylene under a nitrogen atmosphere, wherein the nitrogen flow rate is 10–20 mL / min, preferably 14–18 mL / min; the contact temperature is 240–450 °C, preferably 280–360 °C; the contact time is 10–500 h, preferably 20–350 h; and the pressure is 0.1–2.0 MPa, preferably 0.5–1.5 MPa. Preferably, the reaction is carried out in a fixed-bed reactor, and the mass hourly space velocity (WHSV) of the pseudotrimethylbenzene is 0.5–3.5 h⁻¹. -1 Preferably, it is 0.5 to 1.5 hours. -1 .

3. The method according to claim 1, characterized in that, The molar ratio of silicon (calculated as SiO2) to aluminum (calculated as Al2O3) in the heteroatom EWT structure molecular sieve is 35–180, preferably 40–120; the molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the heteroatom EWT structure molecular sieve is 30–220.

4. The method according to claim 1 or 3, characterized in that, When the heteroatom element is boron, the molar ratio of silicon (calculated as SiO2) to boron (calculated as B2O3) in the heteroatom EWT structure molecular sieve is 120-180, preferably 150-180. When the heteroatom element is one or more of iron, titanium, gallium and germanium, the molar ratio of silicon (calculated as SiO2) to heteroatom elements (calculated as heteroatom oxides) in the heteroatom EWT structure molecular sieve is 120 to 220, preferably 150 to 200.

5. The method according to claim 1, characterized in that, The total acid content of the heteroatom EWT structure molecular sieve, as determined by the NH3-TPD method, is 750–790 μmol / g. The Brønsted acid content, as determined by the pyridine adsorption infrared method at 350 °C, is 30–55 μmol / g, and the Lewis acid content is 70–138 μmol / g. The ratio of Brønsted acid content to Lewis acid content is 0.4–0.

68. The total specific surface area of ​​the heteroatom EWT structured molecular sieve is 500–680 m². 2 / g, preferably 540-650m 2 / g; average pore size is 0.5–20 nm, preferably 2–5 nm; total pore volume is 0.25–0.60 cm³. 3 / g, preferably 0.30~0.55cm 3 / g; the volume of mesopores with a pore size of 2.0–20.0 nm is 0.05–0.35 cm³. 3 / g, preferably 0.10~0.25cm 3 / g; the percentage of mesopore volume with a pore size of 2.0 to 20.0 nm in the total pore volume is 30 to 80%, preferably 35 to 70%; the average particle size of the heteroatom EWT structure molecular sieve is 0.2 to 1.5 μm, preferably 0.3 to 1.0 μm; the relative crystallinity is 50 to 100%, preferably 65 to 90%; Preferably, the heteroatom EWT structured molecular sieve is a hydrogen-type heteroatom EWT structured molecular sieve.

6. The method according to claim 1, characterized in that, The method further includes preparing the catalyst using the following steps: (1) A silicon source, a heteroatom element source, a first alkali source, a first organic template agent and water are mixed, and the resulting first material to be crystallized is subjected to a first crystallization to obtain molecular sieve raw powder; the molecular sieve raw powder is calcined to obtain sodium-type molecular sieve; (2) The sodium molecular sieve is subjected to ion exchange with an acid solution, the obtained molecular sieve intermediate is mixed with an aluminum source, a second alkali source and a second organic template agent, and the obtained second crystallization material is subjected to a second crystallization. The heteroatom elements include one or more of boron, iron, titanium, gallium, and germanium; the first organic template agent and the second organic template agent are respectively a cyclic bis-quaternary ammonium base compound and / or a cyclic bis-quaternary ammonium salt compound; the temperature of the first crystallization is 60–180°C, preferably 100–170°C; the time is 96–168 h, preferably 96–144 h; the temperature of the second crystallization is 60–180°C, preferably 100–170°C; the time is 96–168 h, preferably 96–144 h.

7. The method according to claim 6, characterized in that, The silicon source is selected from one or more of silica sol, water glass, solid silica gel, tetraethyl orthosilicate and fumed silica, preferably solid silica gel; The heteroatom element source is selected from one or more of boron oxide, iron oxide, titanium oxide, gallium oxide and germanium oxide, preferably boron oxide; The first alkali source and the second alkali source are respectively selected from one or more of sodium hydroxide, potassium hydroxide and lithium hydroxide. Preferably, the first alkali source and the second alkali source are both sodium hydroxide. The aluminum source is selected from one or more of aluminum chloride, aluminum sulfate, hydrated aluminum oxide, sodium aluminate and aluminum sol, preferably sodium aluminate; The first organic template agent and the second organic template agent are each selected from at least one having the structure shown in formula (1): R1, R2, R3, and R4 are each independently selected from alkyl groups having 1 to 4 carbon atoms. Preferably, R1, R2, R3, and R4 are each independently selected from one or more of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl, preferably methyl or ethyl; m is 2 or 3; n is any integer from 1 to 10; X - This includes hydroxide ions or halide anions.

8. The method according to claim 6, characterized in that, The silicon source is SiO2, and the heteroatom element source is heteroatom oxide. When the heteroatom element is boron, the molar ratio of SiO2 to B2O3 in the first material to be crystallized is 30 to 180, preferably 60 to 150. When the heteroatom element is one or more of iron, titanium, gallium and germanium, the molar ratio of SiO2 to heteroatom oxide in the first material to be crystallized is 30 to 210, preferably 60 to 180.

9. The method according to claim 6, characterized in that, In step (1), the silicon source is SiO2, the heteroatom element source is heteroatom oxide, the first organic template agent is represented by T1, and when the heteroatom element in the first material to be crystallized is boron, the molar ratio of SiO2 to B2O3 is 30-210, preferably 60-180; when the heteroatom element is one or more of iron, titanium, gallium and germanium, the molar ratio of SiO2 to heteroatom oxide is 30-210, preferably 30-150; and when the heteroatom element is OH... - The molar ratio of the first alkali source to SiO2 is 0 to 1.0, preferably 0.1 to 0.3; the molar ratio of T1 to SiO2 is 0.02 to 0.5, preferably 0.08 to 0.15; and the molar ratio of H2O to SiO2 is 5 to 20, preferably 5 to 10. In step (2), the aluminum source is Al2O3, the second organic template agent is T2, and the molar ratio of SiO2 to Al2O3 in the second material to be crystallized is 30 or more, preferably 30 to 180, more preferably 45 to 150; OH - The molar ratio of the second alkali source to SiO2 is 0.2 to 1.0, preferably 0.2 to 0.5; the molar ratio of T2 to SiO2 is 0.02 to 0.5, preferably 0.08 to 0.15; and the molar ratio of H2O to SiO2 is 5 to 20, preferably 5 to 10.

10. The method according to claim 6, characterized in that, In step (1), the calcination temperature is 400-650℃ and the time is 1-7h; In step (2), the weight ratio of the acid solution to the sodium molecular sieve is (1-100):1, the concentration of the acid solution is 0.01-0.10 mol / L, the temperature of the ion exchange is 60-90℃, and the time is 2-24h; the acid solution is selected from one or more of hydrochloric acid, nitric acid, and sulfuric acid.

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