A mordenite molecular sieve, its preparation method and application

Abstract

The application provides a mordenite molecular sieve and a preparation method and application thereof. The mordenite molecular sieve provided by the application has an acid amount in 8-MR channels of not less than 245 mu mol / g. The preparation method of the mordenite molecular sieve comprises the following steps: aging and crystallizing a sol containing an aluminum source, a first silicon source, a second silicon source, a template agent and a surfactant to obtain mordenite molecular sieve raw powder, wherein the first silicon source comprises water glass, and the second silicon source comprises white carbon black; and drying and calcining the mordenite molecular sieve raw powder to obtain the mordenite molecular sieve. Compared with the existing mordenite molecular sieve, the mordenite molecular sieve provided by the application has a higher B acid amount, and has higher catalytic activity and dimethyl ether conversion rate in a dimethyl ether carbonylation reaction.

Description

Technical Field

[0001] This invention relates to the field of zeolite molecular sieve technology, specifically to a mordenite molecular sieve, its preparation method, and its application. Background Technology

[0002] Zeolite molecular sieves are microporous crystalline aluminosilicate materials. Due to their unique properties, such as strong acidity, high stability, renewability, and good shape selectivity, they are used as important catalysts in modern industry. Mordenite is an important type of aluminosilicate zeolite molecular sieve material, widely used as an important adsorbent and catalyst in petroleum processing and fine chemical industries. The ideal unit cell composition of mordenite is Na₈Al₈Si. 40 O 96 ·nH₂O, belonging to the orthorhombic crystal system, is formed by 5-3 structural units sharing a single edge and then further chaining together, consisting of a 12-membered ring along the

[001] direction and a confined 8-membered ring. Its microporous system consists of two channels: one is an elliptical main 12-membered ring (MR) channel parallel to the c-axis, with a channel size of… Another is an irregularly arranged 8-membered ring (MR) channel parallel to the b-axis, with hole size... For many guest molecules, the pore size of 8MR is too small to allow easy entry and exit. Therefore, mordenite is generally considered to be one-dimensional and can induce diffusion in catalytic applications.

[0003] Mordenite has been proven to be an effective molecular sieve catalyst for the carbonylation of dimethyl ether, particularly due to its high activity and high selectivity for methyl acetate. According to existing reports, the carbonylation mechanism of dimethyl ether on acidic zeolites involves the following steps: first, dimethyl ether adsorbs onto the Brønsted acid site of the mordenite molecular sieve to form a methoxy group. Subsequently, carbon monoxide activates and inserts into the methoxy group to form an acetyl intermediate. Finally, the acetyl group rapidly reacts with another molecule of dimethyl ether to generate methyl acetate and a methoxy group. The methyl acetate then diffuses out through the 12-membered ring. The formation of the acetyl group is the rate-determining step of the entire reaction; therefore, the acidity of the 8-membered ring Brønsted acid significantly affects the catalytic activity of dimethyl ether carbonylation. Thus, the preparation of mordenite zeolites with higher Brønsted acid content is of great significance. Summary of the Invention

[0004] In order to solve one of the above-mentioned technical problems in the prior art, the present invention provides a mordenite molecular sieve, its preparation method and application.

[0005] In a first aspect, the present invention provides a mordenite molecular sieve, wherein the 8-MR channels of the mordenite molecular sieve contain... The acid content is not less than 245 μmol / g.

[0006] According to some embodiments of the present invention, the 8-MR channels of the mordenite molecular sieve are... The acidity is 245-255 μmol / g.

[0007] According to some embodiments of the present invention, the silica-alumina ratio of the silicate zeolite molecular sieve is 10-30, for example, 10, 12, 15, 18, 20, 22, 25, 28, 30 or any value between them, preferably 10-20, more preferably 10-15.

[0008] According to some embodiments of the present invention, the specific surface area of ​​the mordenite molecular sieve is not less than 400 m². 2 ·g -1 For example, 440-460m 2 ·g -1 .

[0009] According to some embodiments of the present invention, the external specific surface area of ​​the mordenite molecular sieve is not less than 40 m². 2 ·g -1 For example, 40-50m 2 ·g -1 .

[0010] According to some embodiments of the present invention, the total acidity of the mordenite molecular sieve calculated by the NH3-TPD method is not less than 1100 μmol / g, for example, 1100-1150 μmol / g.

[0011] On the other hand, the present invention provides a method for preparing mordenite molecular sieves, comprising the following steps:

[0012] A sol containing an aluminum source, a first silicon source, a second silicon source, a template agent, and a surfactant is aged and crystallized to obtain mordenite molecular sieve raw powder; wherein the first silicon source includes water glass and the second silicon source includes silica.

[0013] The raw powder of the silicalite zeolite molecular sieve is dried and calcined to obtain the silicalite zeolite molecular sieve.

[0014] According to some embodiments of the present invention, the sol containing an aluminum source, a first silicon source, a second silicon source, a template agent, and a surfactant is prepared by a method comprising the following steps:

[0015] The aluminum source, the first silicon source, and water are mixed, and then the mixture is further mixed with a template agent and a surfactant to obtain a mixture; the second silicon source is then mixed with the mixture to obtain the sol.

[0016] According to some embodiments of the present invention, the aluminum source includes at least one of aluminum sulfate, aluminum nitrate, aluminum oxide, and sodium aluminate.

[0017] According to some embodiments of the present invention, the template agent includes at least one selected from ethylamine, triethylamine, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide.

[0018] According to some embodiments of the present invention, the surfactant comprises a quaternary ammonium salt cationic surfactant. In some embodiments, the surfactant comprises hexadecyltrimethylammonium bromide (CTAB).

[0019] According to some embodiments of the present invention, in the sol, the molar ratio of Al2O3 to SiO2 is 1:(10-30), for example, 1:10, 1:12, 1:15, 1:18, 1:20, 1:22, 1:25, 1:28, 1:30, or any value between them. In some embodiments, the molar ratio of Al2O3 to SiO2 in the composition is 1:(15-30). In some embodiments, the molar ratio of Al2O3 to SiO2 in the composition is 1:(15-25).

[0020] According to some embodiments of the present invention, in the sol, the molar ratio of Al2O3 to the template agent is 1:(1-3), for example, 1:1, 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, 1:2.8, 1:3, or any value between them. In some embodiments, in the composition, the molar ratio of Al2O3 to the template agent is 1:(1-2). In some embodiments, in the composition, the molar ratio of Al2O3 to the template agent is 1:(1-1.5).

[0021] According to some embodiments of the present invention, in the sol, the molar ratio of Al2O3 to the surfactant is 1:(0.05-0.3), for example, 1:0.05, 1:0.08, 1:0.1, 1:0.12, 1:0.15, 1:0.18, 1:0.2, 1:0.22, 1:0.25, 1:0.28, 1:0.3, or any value between them. In some embodiments, in the composition, the molar ratio of Al2O3 to the surfactant is 1:(0.05-0.15). In some embodiments, in the composition, the molar ratio of Al2O3 to the surfactant is 1:(0.1-0.15).

[0022] According to some embodiments of the present invention, in the sol, the molar ratio of Al2O3 to Na2O is 1:(0.9-1.6), for example, 1:0.9, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, or any value between them. In some embodiments, in the composition, the molar ratio of Al2O3 to Na2O is 1:(1.2-1.6).

[0023] According to some embodiments of the present invention, in the sol, the molar ratio of Al2O3 to water is 1:(500-900), for example, 1:500, 1:550, 1:600, 1:650, 1:700, 1:750, 1:800, 1:850, 1:900, or any value between them. According to some embodiments of the present invention, in the sol, the molar ratio of Al2O3 to water is 1:(600-800).

[0024] According to some embodiments of the present invention, the molar ratio of SiO2:Na2O:Al2O3:templator:surfactant in the sol is (10-30):(0.9-1.6):1:(1-3):(0.05-0.3). In some embodiments, the molar ratio of SiO2:Na2O:Al2O3:templator:surfactant in the sol is (15-25):(1.2-1.6):1:(1-2):(0.05-0.15).

[0025] According to some embodiments of the present invention, the molar ratio of SiO2:Na2O:Al2O3:templator:surfactant:H2O in the sol is (10-30):(0.9-1.6):1:(1-3):(0.05-0.3):(500-900). In some embodiments, the molar ratio of SiO2:Na2O:Al2O3:templator:surfactant:H2O in the sol is (15-25):(1.2-1.6):1:(1-2):(0.05-0.15):(600-800).

[0026] According to some embodiments of the present invention, the aging temperature is 20–80°C, preferably 20–40°C. According to some embodiments of the present invention, the aging time is 1–10 hours, preferably 2–6 hours.

[0027] In this invention, according to some embodiments, the crystallization temperature is 130-190°C, for example, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or any value between them, preferably 150-190°C. According to some embodiments, the crystallization time is 18-72 hours, preferably 24-72 hours. Excessively high crystallization temperatures or excessively long crystallization times will result in higher energy costs.

[0028] According to some embodiments of the present invention, the crystallization is carried out in a homogeneous reactor.

[0029] According to some embodiments of the present invention, the drying temperature is 90-120°C. According to some embodiments of the present invention, the drying time is 8-24 hours.

[0030] According to some embodiments of the present invention, the roasting temperature is 350-650°C, for example, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C or any value between them. According to some embodiments of the present invention, the roasting time is 3-6 hours.

[0031] According to some embodiments of the present invention, the preparation method further includes: subjecting the obtained mordenite molecular sieve to ammonium exchange to obtain H-type mordenite molecular sieve.

[0032] In some embodiments, the ammonium exchange is carried out in an ammonium salt solution and / or ammonia water. The ammonium salts mentioned in this invention include, but are not limited to, ammonium acetate, ammonium carbonate, and ammonium chloride.

[0033] In some embodiments, the ammonium exchange temperature is 60-90°C. In some embodiments, the solid-liquid ratio of the ammonium exchange is 1:(5-15).

[0034] On the other hand, the present invention provides the application of the mordenite molecular sieve as described above or the mordenite molecular sieve prepared by the preparation method described above in the catalytic carbonylation reaction of dimethyl ether.

[0035] The dimethyl ether carbonylation reaction described in this invention includes the reaction of producing methyl acetate by carbonylation of dimethyl ether.

[0036] In some embodiments, the dimethyl ether carbonylation reaction comprises: reacting dimethyl ether and CO under the catalysis of the mordenite molecular sieve described above. In some embodiments, the reaction temperature is 150-250°C. In some embodiments, the reaction pressure is 1-5 MPa. In some embodiments, the dimethyl ether feed rate is 0.1-1.0 Whsv. In some embodiments, the CO feed rate is 150-300 mL / min.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. This invention provides a mordenite molecular sieve with a greater number of Brønsted acid sites. The increased Brønsted acid content results in higher acidity of the molecular sieve, which exhibits better catalytic activity in the dimethyl ether carbonylation reaction and significantly improves the dimethyl ether conversion rate.

[0039] 2. The method for preparing mordenite molecular sieves provided by this invention uses silica and water glass as a mixed silicon source. Compared with conventional synthesis methods that use silica sol as a single silicon source, the synthesized mordenite has a higher Brønsted acid content and higher acidity, resulting in significantly improved catalytic activity and dimethyl ether conversion in the dimethyl ether carbonylation reaction. Furthermore, the water glass acts as both a silicon source and a base, eliminating the need for additional base sources compared to existing technologies. The method of this invention is simple in procedure and highly efficient. Attached Figure Description

[0040] Figure 1 The X-ray diffraction patterns are those of the molecular sieves obtained in Examples 1, 3, 5 and Comparative Example 1.

[0041] Figure 2 The images are scanning electron microscope (SEM) images of the molecular sieves obtained in Examples 1, 3, 5 and Comparative Example 1.

[0042] Figure 3 The nitrogen adsorption diagrams are for the molecular sieves obtained in Example 1 and Comparative Example 1.

[0043] Figure 4 The results are the evaluation results of the dimethyl ether carbonylation catalytic activity of the molecular sieves obtained in Examples 1, 2 and 4, and Comparative Examples 1 and 4. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0045] Unless otherwise specified, all reagents used in the following experiments of this invention are commercially available products or reagents prepared according to conventional methods. Unless otherwise specified, all methods used in the experiments are conventional experimental methods. Unless otherwise specified, all instruments used in the experiments are commercially available.

[0046] In this invention, "specific surface area" refers to the total area of ​​a unit mass sample, including internal and external surface areas. Non-porous samples only have external surface area, such as silicate cement and some clay mineral powders; porous and multi-porous samples have both external and internal surface areas, such as asbestos fibers, diatomaceous earth, and molecular sieves. In porous and multi-porous samples, the surface area of ​​pores with a diameter less than 2 nanometers is the internal surface area, and the surface area after deducting the internal surface area is called the external surface area. The external surface area of ​​a unit mass sample is called the "external specific surface area".

[0047] In this invention, "total pore volume" refers to the volume of all pores (generally only pores with a channel diameter of less than 50 nanometers) per unit mass of molecular sieve; "micropore volume" refers to the volume of all micropores (generally pores with a channel diameter of less than 2 nanometers) per unit mass of molecular sieve.

[0048] The silica used in the following experiments of this invention is spherical under microscopic conditions and is composed of loose polymeric primary particles with a diameter of 10-20 nanometers (the size of the polymeric particles exceeds 100 nanometers, forming dendritic or snowflake-like structures).

[0049] Example 1

[0050] Weigh out the aluminum source (sodium aluminate) and water glass and dissolve it in water. Then add the template agent tetraethylammonium hydroxide and CTAB and stir thoroughly until homogeneous. Then add fumed silica and stir vigorously to form a gel solution with a molar ratio of 20SiO2:1.4Na2O:1Al2O3:1TEAOH:0.1CTAB:700H2O.

[0051] The resulting gel solution was aged at room temperature for 4 hours, and then transferred to a homogeneous reactor at 180°C for crystallization for 48 hours to obtain mordenite molecular sieve raw powder. The obtained mordenite molecular sieve raw powder was washed, dried and calcined to obtain mordenite molecular sieve. The obtained mordenite molecular sieve was subjected to ammonium exchange with ammonium acetate at 80°C with a solid-liquid ratio of 1:10 for 3 times to obtain H-type mordenite, which was then evaluated as a catalyst.

[0052] Example 2

[0053] The difference from Example 1 is that the aluminum source "sodium aluminate" is replaced with "aluminum sulfate", the template agent "tetraethylammonium hydroxide" is replaced with "diethylamine", and the amount of each raw material is adjusted so that the composition of the prepared gel solution is as shown in Table 1, and the aging temperature, crystallization temperature and crystallization time are as shown in Table 1.

[0054] Example 3

[0055] The difference from Example 1 is that the amount of raw materials was adjusted so that the composition of the prepared gel solution is as shown in Table 1, and the aging temperature, crystallization temperature and crystallization time are as shown in Table 1.

[0056] Example 4

[0057] The difference from Example 1 is that the aluminum source "sodium aluminate" is replaced with "aluminum nitrate", and the amount of each raw material is adjusted so that the composition of the prepared gel solution is as shown in Table 1, and the aging temperature, crystallization temperature and crystallization time are as shown in Table 1.

[0058] Example 5

[0059] The difference from Example 1 is that the template agent "tetraethylammonium hydroxide" is replaced with "tetrapropylammonium hydroxide", and the amount of each raw material is adjusted so that the composition of the prepared gel solution is as shown in Table 1, and the aging temperature, crystallization temperature and crystallization time are as shown in Table 1.

[0060] Comparative Example 1

[0061] The experimental procedure is the same as in Example 1, except that the silicon source used is replaced with a conventional silica sol aqueous solution with a silica mass fraction of 40% instead of a mixed silicon source of water glass and silica. At the same time, NaOH is used to adjust the alkalinity, maintaining the same molar ratio of SiO2:Na2O as in Example 1. All other steps are the same as in Example 1, as detailed below:

[0062] Weigh out the aluminum source (sodium aluminate) and dissolve it in water. Then add the silica sol aqueous solution (silicon oxide mass fraction 40%), the template agent tetraethylammonium hydroxide and CTAB, stir thoroughly until uniform, and adjust the alkalinity with NaOH to form a gel solution. The molar ratio of the resulting gel solution is 20SiO2:1.4Na2O:1Al2O3:1TEAOH:0.1CTAB:700H2O.

[0063] The resulting gel solution was aged at room temperature for 4 hours, then transferred to a homogeneous reactor at 180°C for crystallization for 48 hours to obtain raw mordenite molecular sieve powder. The raw mordenite molecular sieve powder was washed, dried, and calcined to obtain mordenite molecular sieve. The obtained mordenite molecular sieve was subjected to ammonium exchange with ammonium acetate at 80°C with a solid-liquid ratio of 1:10 for 3 times to obtain H-type mordenite, which was then evaluated as a catalyst.

[0064] Comparative Example 2

[0065] The difference from Example 1 is that "silica" is replaced with "silica sol aqueous solution (silica mass fraction 40%)", and the raw material feeding ratio is adjusted so that the composition (molar ratio) of the resulting gel solution is the same as that of Example 1.

[0066] The results showed that using "silica sol aqueous solution (silica mass fraction 40%) and water glass as a mixed silicon source" resulted in poor crystallization and the presence of some amorphous material, making it unsuitable as a catalyst.

[0067] Comparative Example 3

[0068] The difference from Example 1 is that "white carbon black" is not added, and the raw material feeding ratio is adjusted so that the composition (molar ratio) of the resulting gel solution is the same as that of Example 1.

[0069] The results show that using water glass as a single silicon source without crystallization cannot synthesize mordenite.

[0070] Comparative Example 4

[0071] The difference from Example 1 is that silica gel and fumed silica are used as a mixed silicon source to synthesize mordenite zeolite molecular sieves. The specific steps are as follows:

[0072] Weigh out the aluminum source (sodium aluminate) and dissolve it in water. Adjust the alkalinity with NaOH. Then add the template agent tetraethylammonium hydroxide and CTAB, and stir thoroughly until homogeneous. Finally, add the silica sol aqueous solution (silica mass fraction 40%) and fumed silica, and stir vigorously to form a gel solution. The molar ratio of the resulting gel solution is 20SiO2:1.4Na2O:1Al2O3:1TEAOH:0.1CTAB:700H2O.

[0073] The resulting gel solution was aged at room temperature for 4 hours, then transferred to a homogeneous reactor at 180°C for crystallization for 48 hours to obtain raw mordenite molecular sieve powder. The raw mordenite molecular sieve powder was washed, dried, and calcined to obtain mordenite molecular sieve. The obtained mordenite molecular sieve was subjected to ammonium exchange with ammonium acetate at 80°C with a solid-liquid ratio of 1:10 for 3 times to obtain H-type mordenite, which was then evaluated as a catalyst.

[0074] Table 1

[0075]

[0076]

[0077]

[0078] Catalyst morphology and structural characterization

[0079] 1. The X-ray diffraction patterns of the molecular sieves prepared in Examples 1, 3, 5 and Comparative Example 1 are as follows: Figure 1 As shown.

[0080] 2. Scanning electron microscope images of the molecular sieves prepared in Examples 1, 3, 5 and Comparative Example 1 are shown below. Figure 2 As shown, from Figure 2 It can be seen that the molecular sieves prepared in Examples 1, 3 and 5 are small crystal blocks with a diameter of less than 100 nm, while the molecular sieve prepared in Comparative Example 1 has a plate-like structure with a diameter of 200-500 nm.

[0081] 3. The nitrogen physical absorption-desorption curves of the molecular sieves were measured using a MicrotTriStar3000 fully automated surface and porosity analyzer. To ensure accuracy, the samples were placed in a 350°C environment in the degassing station and vacuum-dried for 4 hours. The Brunauer-Emmett-Teller equation was used to calculate the surface area of ​​the samples, and the BJH model was used to determine the pore size distribution. The t-plot technique was used to calculate the size, volume, and surface area of ​​the micropores.

[0082] The nitrogen adsorption diagrams of the molecular sieves prepared in Example 1 and Comparative Example 1 are shown below. Figure 3 As shown in Table 2, the molecular sieve prepared in Example 1 has a higher adsorption capacity than the molecular sieve prepared in Comparative Example 1. Specific surface area, external specific surface area, micropore volume, and total pore volume are shown in Table 2.

[0083] 4. The molecular sieve catalysts prepared in Examples 1, 2, 3 and Comparative Example 1 were subjected to determination of silicon-to-aluminum ratio, total TPD acid content, physical adsorption, and pyridine infrared analysis. The results are shown in Table 2.

[0084] The silica-to-alumina ratio of the molecular sieve catalyst was determined using an Agilent 725 ICP-OES analyzer. The specific method was as follows: 20 mg of sample was dispersed in an HF aqueous solution, excess H3BO3 was added, and then the solution was brought to a final volume, followed by a 1 g sample for analysis.

[0085] NH3-TPD is a technique used to characterize the adsorption and dissociation of NH3 molecules on catalysts. By detecting the amount of NH3 released, it determines the amount of adsorption and the degree of dissociation at active sites on the catalyst, thus semi-quantitatively measuring the acid strength of the catalyst. This paper uses an AMI-3300 manufactured by Altamira Instruments for measurement. Before testing, the molecular sieve sample needs to be dried at 550℃ for 1 h, and the heating rate during desorption is 10℃·min. -1 The temperature was increased from 100℃ to 550℃.

[0086] The experimental method for pyridine infrared analysis is as follows: The acid strength and amount of Brønsted (B) and Lewis acids in MOR molecular sieve samples can be measured using Py-IR experiments. This study used a Nicolet NEXUS 670FT-IR spectrometer with a wavenumber range of 4000 cm⁻¹. -1 ~400cm -1The number of scans was 16. Procedure: The molecular sieve sample to be tested was compressed into discs weighing approximately 15 mg and with a diameter of 13 mm. The sample was placed in the center of the sample cell and dried under vacuum at 400℃ for 2 hours. After drying, the background spectrum was photographed and recorded at 400℃, 200℃, and 100℃. After cooling to 100℃, pyridine was adsorbed, followed by vacuum desorption. The sample spectral data were recorded at 100℃, 200℃, and 400℃. After the experiment, the background spectrum at the corresponding temperature was subtracted to obtain the infrared spectral data of pyridine adsorption and desorption.

[0087] Table 2

[0088]

[0089]

[0090] Remark:

[0091] In Table 2 above, The number of (B) and Lewis (L) acid sites was measured by FT-IR (Py-IR) at an adsorption temperature of 200 °C, and the number of acid sites was calculated using the well-known formula B = 1.88ABR. 2 / W, L=1.42ALR 2 / W, where AB and AL represent locations at 1540cm -1 and 1455cm -1 Nearby The combined absorption peak area of ​​the Lewis acid site, where R represents the radius of the catalyst particle and W represents the weight of the catalyst.

[0092] In Table 2 above, B sites in 8-MRc = (strong acid sites analyzed by NH3-TPD) - 12-MR channels characterized by Py-IR analysis Number of acid sites.

[0093] Catalyst activity evaluation

[0094] The mordenite catalysts prepared in Examples 1, 2, and 4, as well as Comparative Examples 1 and 4, were evaluated in the dimethyl ether carbonylation to methyl acetate reaction under the following evaluation conditions:

[0095] 8g of H-type mordenite prepared in Examples 1, 2, and 4, and Comparative Example 1, were weighed and packed into a high-pressure fixed bed. The experimental process parameters were: reaction temperature 200℃, reaction pressure 2.0MPa, dimethyl ether feed rate 0.5Whsv, CO feed rate 200mL / min, and the reaction gas products were analyzed by online analytical chromatography.

[0096] The results of the 25-hour experiment are shown below. Figure 4 It can be seen that the mordenite molecular sieves prepared in Examples 1, 2 and 4 exhibit better activity and higher dimethyl ether conversion rate compared with the mordenite molecular sieves prepared in Comparative Examples 1 and 4.

[0097] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A mordenite molecular sieve, characterized in that, The 8-MR channels of the mordenite molecular sieve The acid content is not less than 245 μmol / g, preferably 245-255 μmol / g.

2. The molecular sieve according to claim 1, characterized in that, The silica-to-alumina ratio of the mordenite molecular sieve is 10-30, preferably 10-20; and / or, The specific surface area of ​​the mordenite molecular sieve is not less than 400 m². 2 ·g -1 Preferably 440-460m 2 ·g -1 ; and / or, The specific surface area of ​​the mordenite molecular sieve is not less than 40 m². 2 ·g -1 Preferably 40-50m 2 ·g -1 ; and / or, The total acid content of the mordenite molecular sieve, calculated by the NH3-TPD method, is not less than 1100 μmol / g, preferably 1100-1150 μmol / g.

3. A method for preparing mordenite molecular sieves, comprising the following steps: A sol containing an aluminum source, a first silicon source, a second silicon source, a template agent, and a surfactant is aged and crystallized to obtain mordenite molecular sieve raw powder; wherein the first silicon source includes water glass and the second silicon source includes silica. The raw powder of the silicalite zeolite molecular sieve is dried and calcined to obtain the silicalite zeolite molecular sieve.

4. The preparation method according to claim 3, characterized in that, The sol was prepared by a method comprising the following steps: The aluminum source, the first silicon source, the template agent, and the surfactant are mixed with water to obtain a mixture; the second silicon source is then mixed with the mixture to obtain the sol.

5. The preparation method according to claim 3 or 4, characterized in that, The aluminum source includes at least one of aluminum sulfate, aluminum nitrate, aluminum oxide, and sodium aluminate; and / or, The template agent includes at least one selected from ethylamine, triethylamine, tetraethylammonium hydroxide, and tetrapropylammonium hydroxide; and / or, The surfactant includes quaternary ammonium salt cationic surfactants, preferably hexadecyltrimethylammonium bromide.

6. The preparation method according to any one of claims 3-5, characterized in that, In the sol, the molar ratio of Al2O3 to SiO2 is 1:(10-30), preferably 1:(15-30); and / or, In the sol, the molar ratio of Al2O3 to the template agent is 1:(1-3), preferably 1:(1-2); and / or, In the sol, the molar ratio of Al2O3 to the surfactant is 1:(0.05-0.3), preferably 1:(0.05-0.15); and / or, In the sol, the molar ratio of Al2O3 to Na2O is 1:(0.9-1.6), preferably 1:(1.2-1.6); and / or, In the sol, the molar ratio of Al2O3 to water is 1:(500-900), preferably 1:(600-800).

7. The preparation method according to any one of claims 3-6, characterized in that, In the sol, the molar ratio of SiO2:Na2O:Al2O3:templator:surfactant:H2O = (10-30):(0.9-1.6):1:(1-3):(0.05-0.3):(500-900); Preferably, in the sol, the molar ratio of SiO2:Na2O:Al2O3:template:surfactant:H2O is (15-30):(1.2-1.6):1:(1-2):(0.05-0.15):(600-800).

8. The preparation method according to any one of claims 3-7, characterized in that, The aging temperature is 20-80℃, preferably 20-40℃, and the aging time is 1-10 hours; and / or, The crystallization temperature is 130-190℃, preferably 150-190℃; the crystallization time is 18-72 hours; and / or, The drying temperature is 90-120℃, and the drying time is 8-24 hours; and / or, The roasting temperature is 350-650℃, and the roasting time is 3-6 hours.

9. The preparation method according to any one of claims 3-8, characterized in that, It also includes the following steps: The mordenite molecular sieve was subjected to ammonium exchange to obtain H-type mordenite molecular sieve; Preferably, the ammonium exchange is carried out in an ammonium salt solution and / or ammonia water, wherein the ammonium salt preferably includes at least one of ammonium acetate, ammonium carbonate, and ammonium chloride; Preferably, the ammonium exchange temperature is 60-90°C and the solid-liquid ratio is 1:(5-15).

10. The application of the mordenite molecular sieve as described in claim 1 or 2, or the mordenite molecular sieve prepared by any one of claims 3-9, in the catalytic carbonylation reaction of dimethyl ether; Preferably, the dimethyl ether carbonylation reaction includes the reaction of dimethyl ether carbonylation to produce methyl acetate.

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