Mcm-22 molecular sieve, method of making and use thereof

Abstract

The application discloses MCM-22 molecular sieve, a preparation method and application thereof. The application adopts a small amount of N,N,N-trimethyladamantylammonium and cyclohexylamine dual organic structure directing agents in a hydrothermal synthesis system, and synthesizes MCM-22 molecular sieve through one-step crystallization and calcination. The method can directly synthesize MCM-22 molecular sieve without adding seeds and without temperature change crystallization operation, and the yield of the MCM-22 molecular sieve prepared after calcination is high. The content of non-framework aluminum in the MCM-22 molecular sieve prepared by the preparation method is less than 5% of the total aluminum content, the content of aluminum located at the half-supercage T2 site of the framework is higher than 10% of the total aluminum content, and the MCM-22 molecular sieve has good performance when used as a catalyst for a liquid phase alkylation reaction of benzene and ethylene to prepare alkylbenzene.

Description

Technical Field

[0001] This invention belongs to the field of molecular sieve synthesis technology, specifically relating to an MCM-22 molecular sieve, its preparation method, and its application. Background Technology

[0002] MWW-structured molecular sieves possess two independent, non-interconnected ten-membered ring channel systems: one set consists of two-dimensional sinusoidal channels with an approximately elliptical cross-section and a pore size of 0.41 nm × 0.51 nm; the other set contains approximately cylindrical twelve-membered ring supercages with dimensions of 0.71 nm × 0.71 nm × 1.82 nm, which are connected to the outside environment through slightly distorted ten-membered ring windows (0.40 nm × 0.55 nm). Typical MWW-type molecular sieves include MCM-22, MCM-49, ITQ-1, SSZ-25, ERB-1, and SCM-1.

[0003] In the synthesis of MCM-22 molecular sieves, expensive or highly toxic piperidine or hexamethyleneimine are typically required as organic structure-directing agents, significantly increasing synthesis costs. CN106517232B discloses a method for synthesizing H-MCM-22 molecular sieves and the synthesized molecular sieve, using hexamethyleneimine, piperidine, and homopiperazine as active structure-directing agents, with a large amount of these active structure-directing agents used. CN114314607A discloses an MCM-22 molecular sieve and its preparation method, as well as a method for alkylation of benzene catalyzed by molecular sieves, wherein the organic structure-directing agents are hexamethyleneimine and morpholine, which are also used extensively and are highly toxic. CN103058210B discloses a method for preparing MCM-22 molecular sieves, using hexamethyleneimine as the organic structure-directing agent; the synthesis steps are complex, and the gas-phase transfer method is difficult to industrialize. Furthermore, when synthesizing MCM-22 molecular sieves using only the seed crystal method, the product yield is extremely low and the amount of seed crystals used is extremely large, which greatly reduces the synthesis efficiency of the molecular sieve. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the preparation process of MCM-22 molecular sieve in the prior art requires the addition of seed crystals and a large amount of organic structure directing agent, which leads to low molecular sieve synthesis efficiency and high cost. The present invention provides an MCM-22 molecular sieve, its preparation method and application. The molecular sieve prepared by this method has a unique chemical composition and morphology. As a catalyst, it is used in the liquid-phase alkylation reaction of benzene and ethylene to produce ethylbenzene and has good catalytic performance.

[0005] The first aspect of the present invention provides an MCM-22 molecular sieve, wherein the content of non-framework aluminum in the MCM-22 molecular sieve is less than 5% of the total aluminum content, and the content of aluminum located at the T2 site of the framework semi-supercage is more than 10% of the total aluminum content, preferably 11% to 15%.

[0006] Furthermore, the MCM-22 molecular sieve crystals have a nanosheet morphology, with a crystal thickness not exceeding 20 nm, preferably 5–16 nm, and a nanosheet size not exceeding 800 nm, preferably 150–800 nm.

[0007] A second aspect of this invention provides a method for preparing MCM-22 molecular sieve, comprising the following steps:

[0008] The MCM-22 molecular sieve is prepared by mixing silicon source, aluminum source, sodium hydroxide, organic structure directing agent a, organic structure directing agent b and water, crystallizing and calcining.

[0009] The silicon source (calculated as SiO2), aluminum source (calculated as Al2O3), sodium hydroxide, organic structure directing agent a (SDA1) (calculated as N,N,N-trimethyladamantane), organic structure directing agent b (SDA2) (calculated as cyclohexylamine), and water are present in a molar ratio of SiO2:Al2O3:NaOH:SDA1:SDA2:H2O = 1:0.020~0.039:0.07~0.22:0.031~0.060:0.020~0.050:12~50, preferably SiO2:Al2O3:NaOH:SDA1:SDA2:H2O = 1:0.021~0.037:0.08~0.20:0.033~0.058:0.022~0.046:14~40.

[0010] Furthermore, the silicon source is silica sol; the aluminum source is sodium aluminate.

[0011] Furthermore, the sodium aluminate contains 38% to 43% Al2O3 by weight and 30% to 33% Na2O by weight.

[0012] Furthermore, the crystallization conditions of the reaction mixture are crystallization at 130–180°C for 2.00–3.75 days, preferably at 140–170°C for 2.25–3.50 days.

[0013] Furthermore, the crystallization process of the reaction mixture is a dynamic crystallization by rotation or stirring, with a rotation or stirring speed of 10 to 300 rpm, preferably 10 to 100 rpm.

[0014] Furthermore, the crystallization can be carried out in any manner conventionally known in the art, such as by mixing the silicon source, aluminum source, sodium hydroxide, organic structure directing agent a, organic structure directing agent b and water in a predetermined ratio, and then heating the resulting mixture under crystallization conditions.

[0015] Furthermore, after the crystallization step, the product can be obtained from the obtained mixture by any conventionally known separation method. Examples of such separation methods include filtering, washing, and drying the obtained mixture. Here, the filtration, washing, and drying can be performed in any manner conventionally known in the art. Specifically, for example, the filtration can be performed by simply vacuum filtering the obtained product mixture. For example, washing can be performed using deionized water and / or ethanol. For example, the drying temperature can be 40–250°C, preferably 60–150°C, and the drying time can be 8–30 h, preferably 10–20 h. This drying can be carried out under normal pressure or under reduced pressure.

[0016] Furthermore, no seed crystals need to be added during the crystallization process of the molecular sieve.

[0017] Furthermore, the molecular sieve before calcination has a schematic chemical composition as shown in the formula "mSiO2·nAl2O3·pSDA1·qSDA2", where 26≤m / n≤50, 15≤m / p≤50, 0.61≤p / q≤3.0, SDA1 is N,N,N-trimethyladamantaneammonium, and SDA2 is cyclohexylamine.

[0018] Furthermore, the molecular sieve before calcination has a schematic chemical composition as shown in the formula "mSiO2·nAl2O3·pSDA1·qSDA2", where 27≤m / n≤48, 16≤m / p≤48, and 0.65≤p / q≤2.90.

[0019] Furthermore, the calcination can be carried out in any manner conventionally known in the art, for example, the calcination temperature is generally 300–800°C, preferably 400–650°C, and the calcination time is generally 1–10 hours, preferably 3–6 hours. In addition, the calcination is generally carried out in an oxygen-containing atmosphere, such as air or an oxygen atmosphere.

[0020] Furthermore, the yield of the MCM-22 molecular sieve product exceeds 80%.

[0021] Furthermore, the content of non-framework aluminum in the MCM-22 molecular sieve is less than 5% of the total aluminum content, and the content of aluminum located at the T2 site of the framework semi-supercage is more than 10% of the total aluminum content, preferably 11% to 15%.

[0022] Furthermore, the MCM-22 molecular sieve crystals have a nanosheet morphology, with a crystal thickness not exceeding 20 nm, preferably 5–16 nm, and a nanosheet size not exceeding 800 nm, preferably 150–800 nm.

[0023] Furthermore, the MCM-22 molecular sieve is a sodium-type MCM-22 molecular sieve, and the total specific surface area of ​​the sodium-type MCM-22 molecular sieve is not less than 450 m². 2 / gram, preferably 450-600 meters 2 / gram; the specific surface area of ​​the sodium-type MCM-22 molecular sieve is not less than 70 m². 2 / gram, preferably 70-150 meters 2 / g; the total pore volume of the sodium-type MCM-22 molecular sieve is not less than 0.70 cm³. 3 / gram, preferably 0.70 to 1.50 cm 3 / g; the micropore volume of the sodium-type MCM-22 molecular sieve is not less than 0.10 cm³. 3 / gram, preferably 0.10 to 0.18 cm 3 / gram.

[0024] Furthermore, the ammonium ion exchange of the molecular sieve involves exchanging the alkali metal cations Na in the sodium-type MCM-22 molecular sieve. + Exchange for NH4 + Sodium-type MWW molecular sieves and ammonium salts are exchanged at a solid-liquid mass ratio of 1:5 to 1:20 at 20 to 60°C for 0.5 to 4 hours. This exchange can be done once or multiple times. After the ammonium ion exchange, the mixture is dried at 60 to 120°C for 4 to 24 hours and then calcined at 400 to 650°C for 1 to 12 hours in an oxygen or air atmosphere to obtain hydrogen-type MCM-22 molecular sieves.

[0025] Furthermore, the ammonium salt used in the exchange is selected from at least one of ammonium chloride, ammonium nitrate, ammonium carbonate, and ammonium sulfate; the concentration of ammonium ions in the ammonium salt solution is 0.1–1 mol / L.

[0026] Furthermore, the total acid content of the hydrogen-type MCM-22 molecular sieve is not less than 600 μmol / g, preferably 600 to 1300 μmol / g; the strong acid content of the molecular sieve is not less than 220 μmol / g, preferably 220 to 500 μmol / g.

[0027] A third aspect of the present invention also provides an MCM-22 molecular sieve composition comprising an MCM-22 molecular sieve prepared according to any of the methods described in the first aspect or according to any of the methods described in the second aspect, and a binder.

[0028] The fourth aspect of the present invention also provides the use of the MCM-22 molecular sieve prepared according to any of the methods described in the first aspect or according to any of the methods described in the second aspect, or the MCM-22 molecular sieve composition described in the third aspect as an adsorbent or a catalyst for the conversion of organic compounds.

[0029] Furthermore, the application is the liquid-phase alkylation of benzene and ethylene to produce alkylbenzene.

[0030] Furthermore, the process conditions are as follows: reaction temperature 150–250℃, reaction pressure 1.0–4.0 MPa, benzene / ethylene molar ratio 1.0–5.0, and ethylene mass hourly space velocity 0.5–10 h⁻¹. 1 .

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] The MCM-22 molecular sieve of this invention is prepared by adding a small amount of dual organic directing agents (N,N,N-trimethyladamantane ammonium and cyclohexylamine) to a hydrothermal synthesis system, followed by one-step crystallization and calcination. The preparation process requires no seed crystals and no temperature-dependent crystallization operation. This method can reduce costs and improve the synthesis efficiency of molecular sieves. The molecular sieve synthesized through the coordinated steps possesses unique properties and shows good catalytic performance and industrial application prospects as a catalyst in the alkylation reaction of benzene and ethylene.

[0033] In the MCM-22 molecular sieve of this invention, the content of non-framework aluminum is less than 5% of the total aluminum content, and the content of aluminum located at the T2 site of the framework semi-supercage is more than 10% of the total aluminum content. The molecular sieve crystals have a nanosheet morphology, the thickness of the crystals is no more than 20 nm, and the size of the nanosheets is no more than 800 nm.

[0034] The MCM-22 molecular sieve of this invention exhibits good catalytic performance as a catalyst in the liquid-phase alkylation of benzene and ethylene to produce ethylbenzene. The conversion rate of the reactant ethylene is >40%, the selectivity of the product ethylbenzene is as high as >91%, and the selectivity of alkylbenzene is as high as >95%. Attached Figure Description

[0035] Figure 1 The X-ray diffraction pattern of the sample in Example 1;

[0036] Figure 2 This is a scanning electron microscope image of the sample in Example 1;

[0037] Figure 3 For the samples in Example 1 and Example 2 13 C10 NMR spectrum;

[0038] Figure 4 For the samples in Example 1 and Example 2 27 Al NMR spectrum;

[0039] Figure 5 The X-ray diffraction pattern of the sample in Example 2;

[0040] Figure 6 This is a scanning electron microscope image of the sample in Example 2;

[0041] Figure 7 The X-ray diffraction pattern of the sample in Example 3;

[0042] Figure 8 This is a scanning electron microscope image of the sample in Example 3;

[0043] Figure 9 The X-ray diffraction pattern of the sample in Example 4;

[0044] Figure 10 This is a scanning electron microscope image of the sample in Example 4;

[0045] Figure 11 The X-ray diffraction pattern of the sample in Comparative Example 1 is shown.

[0046] Figure 12 The X-ray diffraction pattern of the sample in Comparative Example 2;

[0047] Figure 13 The X-ray diffraction pattern of the sample in Comparative Example 3 is shown.

[0048] Figure 14 The X-ray diffraction pattern of the sample in Comparative Example 4;

[0049] Figure 15 For the samples in Comparative Example 4 27 Al NMR spectrum;

[0050] Figure 16 The image shows the X-ray diffraction pattern of the sample in Comparative Example 5. Detailed Implementation

[0051] In the context of this specification, the structure of the molecular sieve is determined by X-ray diffraction (XRD), which is measured using an X-ray powder diffractometer with a Cu-Kα ray source and a nickel filter. Before sample testing, the crystallinity of the molecular sieve sample is observed using a scanning electron microscope (SEM) to confirm that the sample contains only one type of crystal, i.e., the molecular sieve sample is a pure phase. XRD testing is then performed to ensure that there are no interfering peaks from other crystals in the diffraction pattern.

[0052] In the context of this specification, including in the following examples and comparative examples, the X-ray powder diffractometer used for the molecular sieves is a Panalytical X-PERPRO type X-ray powder diffractometer, used to analyze the phase composition of the samples, and a CuKα ray source. Nickel filter, 2θ scanning range 2~50°, operating voltage 40KV, current 40mA, scanning rate 10° / min.

[0053] In the context of this specification, including in the following examples and comparative examples, the scanning electron microscope (SEM) used for the molecular sieves is an S-4800II field emission scanning electron microscope. The molecular sieves were observed using this SEM at a magnification of 40,000x. A random field of view was selected, and the average sum of the crystal sizes in that field of view was calculated. This operation was repeated a total of 10 times, and the average sum of the 10 averages was taken as the crystal size.

[0054] In the context of this specification, including in the following examples and comparative examples, the method for measuring the crystal thickness of the molecular sieve is as follows: the molecular sieve is observed using a transmission electron microscope (FEI G2F30 transmission electron microscope, operating voltage 300kV) at a magnification of 100,000x, a field of view is randomly selected, and the thickness of all crystals in that field of view is measured. This operation is repeated 5 times, and the average value of the 5 measurements is taken as the average thickness of the crystal.

[0055] In the context of this specification, including in the following examples and comparative examples, the pore volume, specific surface area, and external specific surface area of ​​the molecular sieve were measured by the nitrogen physical adsorption-desorption method (BET method): the nitrogen physical adsorption-desorption isotherm of the molecular sieve was measured using a Micromeretic ASAP2020M physical adsorption instrument, and then calculated using the BET equation and t-plot equation. The experimental conditions for this molecular sieve were: measurement temperature -196°C; before measurement, the molecular sieve was heat-treated at 550°C in air for 6 hours, and then pretreated in vacuum at 350°C for 4 hours.

[0056] In the context of this specification, including in the following examples and comparative examples, the content of each element in the molecular sieve was determined by inductively coupled plasma atomic emission spectrometry (ICP) using a Varian 725-ES instrument. The analytical sample was dissolved in hydrofluoric acid prior to the test, and the content was expressed in moles.

[0057] In the context of this specification, including the following examples and comparative examples, the acid content of the molecular sieves was determined using NH3-TPD chemisorption-desorption curves (Altamira AMI-3300 instrument). Before testing, the samples were activated at 550°C for 1 hour, ammonia was adsorbed at 100°C for 20 minutes, and then desorbed and detected at 100–600°C. The acid content corresponding to desorption temperatures above 300°C, determined by Gaussian peak segmentation, can be considered as the acid content of strong acids.

[0058] In the context of this specification, including in the following examples and comparative examples, the content of framework aluminum and non-framework aluminum in the molecular sieve is determined by... 27Al NMR spectroscopy was performed using a Bruker AvanceⅢ / WB-400 instrument. Peaks with chemical shifts around 0 ppm corresponded to non-framework aluminum, while peaks with chemical shifts in the range of 65–35 ppm corresponded to framework aluminum. The percentage of the non-framework aluminum peak area relative to the sum of the two peak areas (total peak area) represents the non-framework aluminum content. Simultaneously, Gaussian peak partitioning was used; the percentage of the area corresponding to the peak with a chemical shift around 60 ppm relative to the total peak area represents the aluminum content at the framework semi-supercage T2 site.

[0059] In the context of this specification, including in the following examples and comparative examples, the types of organic matter in the molecular sieves before calcination are determined by... 13 The chemical shifts of organic compounds in the molecular sieve were determined by comparing them with the standard chemical shifts and peak areas of N,N,N-trimethyladamantane ammonium and cyclohexylamine. The chemical shifts of standard cyclohexylamine were 50.4 ppm, 35.5 ppm, 25.8 ppm, and 24.6 ppm, and the chemical shifts of standard N,N,N-trimethyladamantane ammonium were 73.0 ppm, 48.0 ppm, 36.5 ppm, 32.5 ppm, and 29.8 ppm.

[0060] In the context of this specification, including in the following examples and comparative examples, the organic content in the molecular sieve before calcination was determined by thermogravimetric analysis (TGA) using an SDT Q600 V20.9 Build 20 instrument. The sample was heated from 50°C to 800°C at a rate of 10°C / min in air or oxygen atmosphere to detect weight loss. The percentage of weight loss of the sample within the range of 200–700°C was taken as the organic content of the sample.

[0061] In the context of this specification, including in the following examples and comparative examples, the yield of molecular sieves refers to the percentage of the mass of the calcined sample relative to the sum of the masses of SiO2 and Al2O3 contained in the raw material.

[0062] In the context of this specification, including in the following examples and comparative examples, the catalyst is used to carry out the alkylation reaction of benzene and olefins:

[0063] Benzene conversion rate % = (molar amount of benzene in feed - molar amount of benzene in effluent) / (molar amount of benzene in feed) × 100%.

[0064] Selectivity of alkylbenzene % = (molar amount of target alkylbenzene in the product) / (total molar amount of alkylbenzene in the product) × 100%.

[0065] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0066] Example 1

[0067] A mixture was prepared by stirring 17.51 ​​g of deionized water, 0.725 g of sodium aluminate (containing 40.5 wt% Al₂O₃ and 30.6 wt% Na₂O), 0.145 g of sodium hydroxide, 3.64 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.34 g of cyclohexylamine (organic structure directing agent b), and 12.98 g of silica sol (containing 40.0 wt% SiO₂) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0068] SiO2 / Al2O3 = 30;

[0069] NaOH / SiO2 = 0.12;

[0070] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.05;

[0071] Cyclohexylamine / SiO2 = 0.040;

[0072] H2O / SiO2 = 18.

[0073] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 20 rpm for 3 days. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and then calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 91 wt%, and the specific surface area was 546 m². 2 / gram, with an external specific surface area of ​​125 m² measured by the BET method. 2 / g; Total pore volume 1.16cm 3 / gram, micropore volume is 0.15 cm³ 3 / gram.

[0074] The XRD pattern of the molecular sieve before calcination is shown below. Figure 1 As shown, this is the MCM-22 molecular sieve with an MWW structure; the SEM image is shown below. Figure 2 As shown, the crystals are in the form of nanosheets, with a thickness of 11 nm and a size of 420 nm. Inductively coupled plasma atomic emission spectrometry (ICP) determined the SiO2 / Al2O3 molar ratio of the molecular sieve before calcination to be 30.1; the molecular sieve before calcination... 13 The C NMR spectrum is as follows Figure 3As shown, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) is 1:0.8, and the chemical composition of the molecular sieve before calcination is "1SiO2·0.033Al2O3·0.045SDA1·0.038SDA2". The molecular sieve before calcination... 27 Al NMR spectrum as shown Figure 4 As shown, the aluminum content in the non-skeletal structure is 3.5%, and the aluminum content at the T2 site of the skeletal semi-supercage is 13.2%.

[0075] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 1032 μmol / g and the strong acid content was 387 μmol / g by NH3-TPD.

[0076] Example 2

[0077] A mixture was prepared by stirring 12.80 g of deionized water, 0.845 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.229 g of sodium hydroxide, 2.52 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.27 g of cyclohexylamine (organic structure directing agent b), and 13.61 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0078] SiO2 / Al2O3 = 27;

[0079] NaOH / SiO2 = 0.15;

[0080] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.033;

[0081] Cyclohexylamine / SiO2 = 0.030;

[0082] H2O / SiO2 = 14.

[0083] The mixture was placed in a stainless steel reactor and heated to crystallize at 165°C with a stirring speed of 40 rpm for 2.5 days. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and then calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 92 wt%, and the specific surface area was 515 m². 2 / gram, with an external specific surface area of ​​86 m² measured by the BET method. 2 / g; Total pore volume 0.91cm 3 / gram, micropore volume is 0.17 cm³ 3 / gram.

[0084] The XRD pattern of the molecular sieve before calcination is shown below. Figure 5 As shown, this is the MCM-22 molecular sieve with an MWW structure; the SEM image is shown below. Figure 6 As shown, the crystals are in the form of nanosheets, with a thickness of 16 nm and a size of 460 nm. The SiO2 / Al2O3 molar ratio of the molecular sieve before calcination was determined to be 27.2 using inductively coupled plasma atomic emission spectrometry (ICP). The molecular sieve before calcination... 13 The C NMR spectrum is as follows Figure 3 As shown, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) is 1:1.3, and the chemical composition of the molecular sieve before calcination is "1SiO2·0.037Al2O3·0.021SDA1·0.027SDA2". The molecular sieve before calcination... 27 Al NMR spectrum as shown Figure 4 As shown, the aluminum content in the non-skeletal structure is 4.1%, and the aluminum content at the T2 site of the skeletal semi-supercage is 14.8%.

[0085] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 1163 μmol / g and the strong acid content was 466 μmol / g by NH3-TPD.

[0086] Example 3

[0087] A mixture was prepared by stirring 17.44 g of deionized water, 0.738 g of sodium aluminate (containing 42.5 wt% Al2O3 and 30.6 wt% Na2O), 0.486 g of sodium hydroxide, 5.16 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.37 g of cyclohexylamine (organic structure directing agent b), and 16.15 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0088] SiO2 / Al2O3 = 35;

[0089] NaOH / SiO2 = 0.18;

[0090] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.057;

[0091] Cyclohexylamine / SiO2 = 0.035;

[0092] H2O / SiO2 = 16.

[0093] The mixture was placed in a stainless steel reactor and heated to crystallize at 165°C and a stirring speed of 30 rpm for 2.25 days. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 89 wt%, the specific surface area was 556 m² / g, and the external specific surface area measured by the BET method was 136 m² / g. 2 / g; Total pore volume 1.24 cm 3 / gram, with a micropore volume of 0.14 cm³ / gram.

[0094] The XRD pattern of the molecular sieve before calcination is shown below. Figure 7 As shown, this is the MCM-22 molecular sieve with an MWW structure; the SEM image is shown below. Figure 8 As shown, the crystals are in the form of nanosheets, with a thickness of 10 nm and a size of 440 nm. The SiO2 / Al2O3 molar ratio of the molecular sieve before calcination was determined to be 34.8 using inductively coupled plasma atomic emission spectrometry (ICP). The molecular sieve before calcination... 13 C NMR spectrum and Figure 3 Similar to Example 1, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) was 1:0.7, and the chemical composition of the molecular sieve before calcination was "1SiO2·0.029Al2O3·0.048SDA1·0.034SDA2". The molecular sieve before calcination... 27 Al NMR spectrum and Figure 4 Similar to Example 1, the content of non-skeletal aluminum is 3.8%, and the content of aluminum at the T2 site of the skeletal semi-supercage is 12.9%.

[0095] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 915 μmol / g and the strong acid content was 338 μmol / g by NH3-TPD.

[0096] Example 4

[0097] A mixture was prepared by stirring 46.91 g of deionized water, 0.577 g of sodium aluminate (containing 40.5 wt% Al₂O₃ and 30.6 wt% Na₂O), 0.189 g of sodium hydroxide, 3.55 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.41 g of cyclohexylamine (organic structure directing agent b), and 13.78 g of silica sol (containing 40.0 wt% SiO₂) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0098] SiO2 / Al2O3 = 40;

[0099] NaOH / SiO2 = 0.11;

[0100] N,N,N-trimethyladamantane ammonium / SiO2 = 0.046;

[0101] Cyclohexylamine / SiO2 = 0.045;

[0102] H2O / SiO2 = 35.

[0103] The mixture was placed in a stainless steel reactor and heated to crystallize at 155°C and 10 rpm for 3.5 days. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and then calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 87 wt%, and the specific surface area was 562 m². 2 / gram, with an external specific surface area of ​​118 m² measured by the BET method. 2 / g; Total pore volume 0.98cm 3 / gram, micropore volume is 0.15 cm³ 3 / gram.

[0104] The XRD pattern of the molecular sieve before calcination is shown below. Figure 9 As shown, this is the MCM-22 molecular sieve with an MWW structure; the SEM image is shown below. Figure 10 As shown, the crystals are in the form of nanosheets, with a thickness of 11 nm and a size of 380 nm. The SiO2 / Al2O3 molar ratio of the molecular sieve before calcination was determined to be 40.3 using inductively coupled plasma atomic emission spectrometry (ICP). The molecular sieve before calcination... 13 C NMR spectrum and Figure 3 Similar to Example 1, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) was 1:1.0, and the chemical composition of the molecular sieve before calcination was "1SiO2·0.025Al2O3·0.041SDA1·0.042SDA2". The molecular sieve before calcination... 27 Al NMR spectrum and Figure 4Similar to Example 1, the content of non-skeletal aluminum is 3.6%, and the content of aluminum at the T2 site of the skeletal semi-supercage is 13.5%.

[0105] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 813 μmol / g and the strong acid content was 274 μmol / g by NH3-TPD.

[0106] Example 5

[0107] A mixture was prepared by stirring 30.07 g of deionized water, 0.579 g of sodium aluminate (containing 40.5 wt% Al₂O₃ and 33 wt% Na₂O), 0.318 g of sodium hydroxide, 3.12 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.26 g of cyclohexylamine (organic structure directing agent b), and 15.90 g of silica sol (containing 40.0 wt% SiO₂) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0108] SiO2 / Al2O3 = 46;

[0109] NaOH / SiO2 = 0.13;

[0110] N,N,N-trimethyladamantane ammonium / SiO2 = 0.035;

[0111] Cyclohexylamine / SiO2 = 0.025;

[0112] H2O / SiO2 = 22.

[0113] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C and 80 rpm for 2.75 days. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and then calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 86 wt%, and the specific surface area was 497 m². 2 / gram, with an external specific surface area of ​​93 m² measured by the BET method. 2 / g; Total pore volume 0.86cm 3 / gram, micropore volume is 0.17 cm³ 3 / gram.

[0114] XRD pattern of molecular sieve before calcination and Figure 1 Similarly, it is an MCM-22 molecular sieve with an MWW structure; the SEM image is similar to... Figure 2 Similarly, the crystals are in the form of nanosheets, with a thickness of 13 nm and a size of 490 nm. The SiO2 / Al2O3 molar ratio of the molecular sieve before calcination was determined to be 45.6 using inductively coupled plasma atomic emission spectrometry (ICP). The molecular sieve before calcination... 13 C NMR spectrum and Figure 3 Similar to Example 1, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) was 1:1.0, and the chemical composition of the molecular sieve before calcination was "1SiO2·0.022Al2O3·0.025SDA1·0.024SDA2". The 27Al NMR spectrum of the molecular sieve before calcination is... Figure 4 Similar to Example 2, the content of non-skeletal aluminum is 3.9%, and the content of aluminum at the T2 site of the skeletal semi-supercage is 14.6%.

[0115] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 646 μmol / g and the strong acid content was 229 μmol / g by NH3-TPD.

[0116] Example 6

[0117] A mixture was prepared by stirring 38.75 g of deionized water, 0.658 g of sodium aluminate (containing 40.5 wt% Al₂O₃ and 30.6 wt% Na₂O), 0.414 g of sodium hydroxide, 3.69 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.24 g of cyclohexylamine (organic structure directing agent b), and 16.48 g of silica sol (containing 40.0 wt% SiO₂) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0118] SiO2 / Al2O3 = 42;

[0119] NaOH / SiO2 = 0.15;

[0120] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.040;

[0121] Cyclohexylamine / SiO2 = 0.022;

[0122] H2O / SiO2 = 26.

[0123] The mixture was placed in a stainless steel reactor and heated to crystallize at 170°C and a stirring speed of 30 rpm for 2.25 days. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and then calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 87 wt%, and the specific surface area was 541 m². 2 The specific surface area measured by the BET method is 129 m² / g; the total pore volume is 0.95 cm³ / g, and the micropore volume is 0.15 cm³ / g. 3 / gram.

[0124] XRD pattern of molecular sieve before calcination and Figure 1 Similarly, it is an MCM-22 molecular sieve with an MWW structure; the SEM image is similar to... Figure 2 Similarly, the crystals are in the form of nanosheets, with a thickness of 12 nm and a size of 520 nm. The SiO2 / Al2O3 molar ratio of the molecular sieve before calcination was determined to be 42.0 using inductively coupled plasma atomic emission spectrometry (ICP). The molecular sieve before calcination... 13 C NMR spectrum and Figure 3 Similar to Example 1, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) was 1:0.6, and the chemical composition of the molecular sieve before calcination was "1SiO2·0.024Al2O3·0.035SDA1·0.022SDA2". The 27Al NMR spectrum of the molecular sieve before calcination is... Figure 4 Similar to Example 2, the content of non-skeletal aluminum is 4.6%, and the content of aluminum at the T2 site of the skeletal semi-supercage is 14.4%.

[0125] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 779 μmol / g and the strong acid content was 245 μmol / g by NH3-TPD.

[0126] Example 7

[0127] A mixture was prepared by stirring 34.22 g of deionized water, 0.820 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.383 g of sodium hydroxide, 3.44 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.41 g of cyclohexylamine (organic structure directing agent b), and 16.14 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0128] SiO2 / Al2O3 = 33;

[0129] NaOH / SiO2 = 0.16;

[0130] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.038;

[0131] Cyclohexylamine / SiO2 = 0.038;

[0132] H2O / SiO2 = 24.

[0133] The mixture was placed in a stainless steel reactor and heated to crystallize at 165°C with a stirring speed of 50 rpm for 2.5 days. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and then calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 89 wt%, and the specific surface area was 506 m². 2 / gram, with an external specific surface area of ​​91 m² measured by the BET method. 2 / g; Total pore volume 0.82cm 3 / gram, micropore volume is 0.17 cm³ 3 / gram.

[0134] XRD pattern of molecular sieve before calcination and Figure 1 Similarly, it is an MCM-22 molecular sieve with an MWW structure; the SEM image is similar to... Figure 2 Similarly, the crystals are in the form of nanosheets, with a thickness of 15 nm and a size of 550 nm. The SiO2 / Al2O3 molar ratio of the molecular sieve before calcination was determined to be 33.1 using inductively coupled plasma atomic emission spectrometry (ICP). The molecular sieve before calcination... 13 C NMR spectrum and Figure 3 Similar to Example 1, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) was 1:1.2, and the chemical composition of the molecular sieve before calcination was "1SiO2·0.030Al2O3·0.029SDA1·0.035SDA2". The molecular sieve before calcination... 27 Al NMR spectrum and Figure 4Similar to Example 2, the non-skeletal aluminum content was 4.4%, and the aluminum content at the T2 site of the skeletal semi-supercage was 14.1%.

[0135] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 947 μmol / g and the strong acid content was 352 μmol / g by NH3-TPD.

[0136] Example 8

[0137] A mixture was prepared by stirring 24.84 g of deionized water, 0.677 g of sodium aluminate (containing 40.5 wt% Al2O3 and 30.6 wt% Na2O), 0.443 g of sodium hydroxide, 3.70 g of N,N,N-trimethyladamantane ammonium solution (containing 25.12 wt% N,N,N-trimethyladamantane ammonium) (organic structure directing agent a), 0.43 g of cyclohexylamine (organic structure directing agent b), and 15.35 g of silica sol (containing 40.0 wt% SiO2) at room temperature for 3 hours. The final material ratio (molar ratio) was:

[0138] SiO2 / Al2O3 = 38;

[0139] NaOH / SiO2 = 0.17;

[0140] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.043;

[0141] Cyclohexylamine / SiO2 = 0.042;

[0142] H2O / SiO2 = 20.

[0143] The mixture was placed in a stainless steel reactor and heated at 160°C with a stirring speed of 100 rpm for 3.25 days to crystallize. After crystallization, the mixture was filtered, washed, dried overnight in an oven at 100°C, and then calcined in air at 550°C for 6 hours to obtain sodium-type MCM-22 molecular sieve. The yield of the molecular sieve was 91 wt%, and the specific surface area was 472 m². 2 / gram, with an external specific surface area of ​​104 m² / g as measured by the BET method; total pore volume of 0.77 cm³. 3 / gram, micropore volume is 0.16 cm³ 3 / gram.

[0144] XRD pattern of molecular sieve before calcination and Figure 1 Similarly, it is an MCM-22 molecular sieve with an MWW structure; the SEM image is similar to... Figure 2Similarly, the crystals are in the form of nanosheets, with a thickness of 14 nm and a size of 360 nm. The SiO2 / Al2O3 molar ratio of the molecular sieve before calcination was determined to be 38.4 using inductively coupled plasma atomic emission spectrometry (ICP). The molecular sieve before calcination... 13 C NMR spectrum and Figure 3 Similar to Example 1, the ratio of N,N,N-trimethyladamantane ammonium (SDA1) to cyclohexylamine (SDA2) was 1:0.9, and the chemical composition of the molecular sieve before calcination was "1SiO2·0.026Al2O3·0.040SDA1·0.037SDA2". The molecular sieve before calcination... 27 Al NMR spectrum and Figure 4 Similar to Example 1, the non-skeletal aluminum content is 3.7%, and the aluminum content at the T2 site of the skeletal semi-supercage is 13.7%.

[0145] Sodium-type molecular sieve was subjected to ammonium ion exchange with 0.2 mol / L NH4NO3 solution (mass ratio 1:20) at 45℃ for 2 hours, followed by centrifugation and washing. The ammonium ion exchange was repeated twice. The resulting sample was dried overnight at 100℃ and calcined in air at 550℃ for 6 hours to obtain hydrogen-type MCM-22 molecular sieve sample. The total acid content of the molecular sieve was determined to be 858 μmol / g and the strong acid content was 311 μmol / g by NH3-TPD.

[0146] Comparative Example 1

[0147] The material ratio and crystallization temperature are the same as in Example 1, except that the synthesis time is extended to 5 days.

[0148] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 20 rpm for 5 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 11 As shown, the sample is a mixture of FER and MWW structures, and is not an MWW molecular sieve.

[0149] Comparative Example 2

[0150] The material ratio is the same as in Example 1, except that N,N,N-trimethyladamantane ammonium (SDA1) is not added. The final material ratio (molar ratio) is:

[0151] SiO2 / Al2O3 = 30;

[0152] NaOH / SiO2 = 0.12;

[0153] Cyclohexylamine / SiO2 = 0.04;

[0154] H2O / SiO2 = 18.

[0155] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 20 rpm for 3 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 12 As shown, the sample did not crystallize and was an amorphous material, therefore it is not an MWW molecular sieve.

[0156] Comparative Example 3

[0157] The material ratio is the same as in Example 3, except that cyclohexylamine (SDA2) is not added. The final material ratio (molar ratio) is:

[0158] SiO2 / Al2O3 = 35;

[0159] NaOH / SiO2 = 0.18;

[0160] N,N,N-Trimethyladamantaneammonium / SiO2 = 0.057;

[0161] H2O / SiO2 = 16.

[0162] The mixture was placed in a stainless steel reactor and heated at 165°C with a stirring speed of 30 rpm for 2.25 days to crystallize. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 13 As shown, the sample did not crystallize and was an amorphous material, not a MWW molecular sieve.

[0163] Comparative Example 4

[0164] The material ratio is the same as in Example 1, except that more N,N,N-trimethyladamantane ammonium is added. The final material ratio (molar ratio) is:

[0165] SiO2 / Al2O3 = 30;

[0166] NaOH / SiO2 = 0.12;

[0167] N,N,N-trimethyladamantane ammonium / SiO2 = 0.15;

[0168] Cyclohexylamine / SiO2 = 0.04;

[0169] H2O / SiO2 = 18.

[0170] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 20 rpm for 3 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 14 The image shown is of the MWW molecular sieve. However, the sample... 27 Al NMR spectrum as shown Figure 15 As shown, the content of non-skeletal aluminum is 6.6%, and the content of aluminum at the T2 site of the skeletal semi-supercage is 5.9%.

[0171] Comparative Example 5

[0172] The material ratio is the same as in Example 1, except that the added sodium aluminate contains different contents of Al2O3 and Na2O (containing 50.6% by weight of Al2O3 and 45.2% by weight of Na2O). The raw materials are prepared in the same amount of substances.

[0173] The mixture was placed in a stainless steel reactor and heated to crystallize at 160°C with a stirring speed of 20 rpm for 3 days. After crystallization, the mixture was filtered, washed, and dried overnight in an oven at 100°C. The XRD pattern of the obtained product is shown below. Figure 16 As shown, the raw material was only partially crystallized, and the sample was a mixture of amorphous material and MWW molecular sieve.

[0174] Examples 9-16

[0175] The hydrogen-form MCM-22 molecular sieve powder samples synthesized in Examples 1-8 were crushed and sieved to obtain 0.35 g of the 20-40 mesh particle size fraction, which was then placed in a fixed-bed reactor for liquid-phase alkylation reaction of benzene and ethylene. The reaction conditions were: reaction temperature of 155-220℃, preferably 180-210℃; reaction pressure of 1.5-3.5 MPa; benzene-to-ethylene molar ratio of 1.5-4.5; and ethylene mass hourly space velocity of 2-8 h⁻¹. 1 The specific reaction conditions for each embodiment are shown in Table 1. The products, catalyst activity, and product selectivity were analyzed using a Shimadzu GC-2014 gas chromatograph, as shown in Table 1.

[0176] Comparative Examples 7-8

[0177] Similar to Examples 9-16, the catalyst obtained after treating the hydrogen-type MWW molecular sieve synthesized in Comparative Example 4 was reacted. The catalyst activity and product selectivity are shown in Table 1.

[0178] Table 1. Catalyst performance results for Examples 9-16 and Comparative Examples 7-8

[0179]

[0180] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An MCM-22 molecular sieve, characterized in that, The non-framework aluminum content in the MCM-22 molecular sieve is less than 5% of the total aluminum content, while the aluminum content at the T2 site of the framework semi-supercage is higher than 11% to 15% of the total aluminum content. The MCM-22 molecular sieve crystals have a nanosheet morphology, with a crystal thickness of no more than 20 nm and a nanosheet size of no more than 800 nm. Before calcination, the molecular sieve has a schematic chemical composition as shown in the formula "mSiO2•nAl2O3•pSDA1•qSDA2", where 26≤m / n≤50, 15≤m / p≤50, 0.61≤p / q≤3.0, SDA1 is N,N,N-trimethyladamantaneammonium, and SDA2 is cyclohexylamine.

2. The molecular sieve according to claim 1, characterized in that, The thickness of the MCM-22 molecular sieve crystal is 5~16nm, and the size of the nanosheets is 150~800nm.

3. A method for preparing the MCM-22 molecular sieve according to any one of claims 1-2, comprising the following steps: The MCM-22 molecular sieve is prepared by mixing silicon source, aluminum source, sodium hydroxide, organic structure directing agent a, organic structure directing agent b and water, crystallizing and calcining. The silicon source is calculated as SiO2, the aluminum source as Al2O3, sodium hydroxide, organic structure directing agent a as N,N,N-trimethyladamantane ammonium, organic structure directing agent b as cyclohexylamine, and water, in a molar ratio of SiO2:Al2O3:NaOH:SDA1:SDA2:H2O=1:0.020~0.039:0.07~0.22:0.031~0.060:0.020~0.050:12~50; The aluminum source is sodium aluminate, wherein the content of Al2O3 in the sodium aluminate is 38%~43% by weight, and the content of Na2O is 30%~33% by weight. The reaction mixture was crystallized at 130-180°C for 2.00-3.75 days.

4. The preparation method according to claim 3, characterized in that, The silicon source is calculated as SiO2, the aluminum source as Al2O3, sodium hydroxide, organic structure directing agent a as N,N,N-trimethyladamantane ammonium, organic structure directing agent b as cyclohexylamine, and water, in a molar ratio of SiO2:Al2O3:NaOH:SDA1:SDA2:H2O=1:0.021~0.037:0.08~0.20:0.033~0.058:0.022~0.046:14~40.

5. The preparation method according to claim 3 or 4, characterized in that, The silicon source is silica sol.

6. The preparation method according to claim 5, characterized in that, The reaction mixture was crystallized at 140-170°C for 2.25-3.50 days.

7. The preparation method according to claim 3, characterized in that, The crystallization process of the reaction mixture is a dynamic crystallization by rotation or stirring, with a rotation or stirring speed of 10~300 rpm.

8. The preparation method according to claim 7, characterized in that, The rotation or stirring speed is 10~100 rpm.

9. The preparation method according to claim 3, characterized in that, No seed crystals need to be added during the crystallization process of the molecular sieve.

10. The preparation method according to claim 3, characterized in that, 27≤m / n≤48, 16≤m / p≤48, 0.65≤p / q≤2.

90.

11. An MCM-22 molecular sieve composition comprising the MCM-22 molecular sieve according to any one of claims 1 to 2 or the MCM-22 molecular sieve prepared according to any one of claims 3 to 10, and a binder.

12. The use of the MCM-22 molecular sieve according to any one of claims 1 to 2, or the MCM-22 molecular sieve prepared according to any one of claims 3 to 10, or the MCM-22 molecular sieve composition according to claim 11 as a catalyst for the conversion of organic compounds.

13. The application according to claim 12, characterized in that, The application is the liquid-phase alkylation of benzene and ethylene to produce alkylbenzene.

14. The application according to claim 13, characterized in that, The process conditions are: reaction temperature 150~250℃, reaction pressure 1.0~4.0MPa, benzene / ethylene molar ratio 1.0~5.0, ethylene mass space velocity 0.5~10h -1 .

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