A ZSM-5 molecular sieve and its preparation and application

Abstract

This invention discloses a ZSM-5 molecular sieve and its preparation and application. The preparation method of the ZSM-5 molecular sieve includes: (a) mixing silicon source I, aluminum source I, water, and template agent I, followed by a first closed-loop treatment to obtain mixture A; (b) mixing mixture A with organic compound I, followed by a second closed-loop treatment to obtain mixture B; (c) mixing mixture B, silicon source II, aluminum source II, water, template agent II, and organic compound II to obtain mixture C; (d) crystallizing mixture C, followed by liquid-solid separation, washing, and drying to obtain the molecular sieve. The first closed-loop treatment conditions are: temperature 10-40℃, time 5-15 hours; the second closed-loop treatment conditions are: temperature 80-130℃, time 1-5 hours. The ZSM-5 molecular sieve of this invention, when used as a catalyst in the alkylation of benzene and ethylene to produce ethylbenzene, exhibits a significantly extended catalyst lifetime.

Description

Technical Field

[0001] This invention belongs to the technical field of catalytic chemistry and chemical engineering, and in particular relates to a ZSM-5 molecular sieve and its preparation and application. Background Technology

[0002] Ethylbenzene is an important organic chemical raw material that plays a vital role in the development of the national economy. Its downstream applications are mainly in the production of styrene, which in turn produces polymer materials such as ABS and PS, and are widely used in the automotive, electronics, aerospace, urban construction, and daily necessities industries.

[0003] Over 90% of ethylbenzene is produced by the alkylation reaction of benzene and ethylene in the presence of acidic molecular sieves. Depending on the reaction process, this can be divided into liquid-phase and gas-phase methods. The gas-phase method is suitable for various ethylene feedstocks, including pure ethylene, dilute ethylene, or ethanol. However, the gas-phase reaction temperature exceeds 320℃, making it prone to a series of side reactions that produce heavy components and tar. Over long periods, carbon deposits form, clogging the molecular sieve pores and reducing catalyst activity, necessitating catalyst regeneration. Developing catalysts with long-term stability to extend catalyst lifespan and reduce regeneration frequency can effectively save costs and minimize disruption to normal plant operations.

[0004] CN102875316A discloses a method for producing ethylbenzene by alkylation of dry gas and benzene. The method uses dry gas and benzene as reactants, and the reactants react with a catalyst to undergo a gas-phase alkylation reaction to produce ethylbenzene. The catalyst used contains the following components by weight percentage: a) 40-90% ZSM-5 molecular sieve with a crystal diameter of 5-500 nm and a silicon-aluminum molar ratio of SiO2 / Al2O3 of 30-400; b) 9-59% binder alumina or silica; c) 0.1-10% alkaline earth metal oxides and 0.1-10% rare earth metal oxides. The high-temperature steam treatment of the catalyst effectively solves the problems of poor catalyst stability and short regeneration cycle. However, the ethylene feedstock applicable to this method is dry gas, where the ethylene mass concentration is generally 10-20 wt.%, and it is not further explained whether it is applicable to feedstock gases with higher ethylene concentrations.

[0005] CN108080019A discloses a method for preparing a highly selective benzene alkylation strip catalyst. The method uses a high-silicon-to-alumina ratio (HSR) MFI zeolite molecular sieve as the catalyst matrix. The HSR MFI zeolite molecular sieve is extruded into strips using the hydrolysate of acidified silicone grease. The catalyst is then treated with the mother liquor obtained during the hydrothermal crystallization of the HSR MFI zeolite molecular sieve, and borate is added to the mother liquor. An ion exchange method is used to convert the extruded HSR MFI zeolite molecular sieve strips treated with the mother liquor into a hydrogen-form alkylation catalyst. This method utilizes the mother liquor generated during the hydrothermal synthesis of the HSR MFI zeolite molecular sieve to treat the strip catalyst, not only recovering useful components from the mother liquor and clearing the catalyst's pores, but also reducing environmental pollution throughout the entire alkylation catalyst production chain. Adding an appropriate amount of borate to the mother liquor during the catalyst treatment improves the mechanical strength of the catalyst particles, which helps extend the catalyst's lifespan. However, this method does not provide a detailed comparison of the specific lifespan of the catalysts, and the applicable raw material is ethanol, without further explanation as to whether it is applicable to dilute ethylene or pure ethylene raw materials. Summary of the Invention

[0006] To address the short lifespan of existing catalysts for the alkylation of benzene and ethylene to ethylbenzene, this invention provides a ZSM-5 molecular sieve, its preparation, and its application. The catalyst prepared using the ZSM-5 molecular sieve of this invention is particularly suitable for the reaction of benzene and high-concentration ethylene alkylation to ethylbenzene, exhibiting a significantly extended catalyst lifespan.

[0007] The first aspect of this invention provides a method for preparing ZSM-5 molecular sieve, comprising:

[0008] (a) Mix silicon source I, aluminum source I, water and template agent I, and after a first sealed treatment, obtain mixture A;

[0009] (b) Mixture A and organic matter I are mixed and subjected to a second sealing process to obtain mixture B;

[0010] (c) Mix mixture B, silicon source II, aluminum source II, water, template agent II and organic matter II to obtain mixture C;

[0011] (d) After crystallization, the mixture C is subjected to liquid-solid separation, washing, and drying to obtain the molecular sieve;

[0012] The first sealing treatment conditions are: temperature 10-40℃, time 5-15 hours; the second sealing treatment conditions are: temperature 80-130℃, time 1-5 hours.

[0013] In the above technical solution, preferably, step (a) has one or more of the following features:

[0014] In the above technical solution, preferably, the silicon source I in step (a) is one or more of tetraethyl silicate, tetrapropyl silicate, and tetrabutyl silicate;

[0015] In the above technical solution, preferably, in step (a), aluminum source I is one or more of aluminum sulfate, aluminum isopropoxide, sodium aluminate, and boehmite;

[0016] In the above technical solution, preferably, in step (a), template agent I is one or more of tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-butylamine, butanediamine, hexamethyleneimine, piperidine, piperazine, and homopiperazine;

[0017] In the above technical solution, preferably, the molar ratios of silicon source I, aluminum source I, water and template agent I in step (a) are as follows: silicon source I: aluminum source I: water: template agent I = 1:(0.0025-0.025):(5-20):(0.1-1.0), wherein silicon source I and aluminum source I are calculated as SiO2 and Al2O3, respectively.

[0018] In the above technical solution, preferably, the first sealing treatment in step (a) and the second sealing treatment in step (b) are both carried out under stirring conditions.

[0019] In the above technical solution, preferably, in step (b), organic compound I is a silane containing aminopropyl, preferably one or more of diethylenetriaminepropylmethyldimethoxysilane, N-aminoethyl-3-aminopropylmethyldiethoxysilane or N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane.

[0020] In the above technical solution, preferably, the molar ratio of organic compound I to mixture A, calculated as SiO2, is organic compound I:SiO2 = (0.02-0.3):1.

[0021] In the above technical solution, preferably, step (c) has one or more of the following features:

[0022] In the above technical solution, preferably, the silicon source II in step (c) is one or more of silica sol, silica fume, silica powder, tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, and tetrabutyl silicate.

[0023] In the above technical solution, preferably, the aluminum source II in step (c) is one or more of aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum isopropoxide, sodium aluminate, and boehmite;

[0024] In the above technical solution, preferably, in step (c) the template agent II is one or more of tetrapropylammonium bromide, tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-propylamine, propylenediamine, n-butylamine, butylenediamine, n-hexylamine, hexamethylenediamine, ammonia, hexamethyleneimine, piperidine, piperazine, and hyperpiperazine;

[0025] In the above technical solution, preferably, the organic compound II in step (c) is a phenyl-containing disilazine, preferably one or more of 1,3-diphenyltetraethyldisilazine, 1,3-dichloro-1,1,3,3-tetraphenyldisilazine, or 1,3-dimethyl-1,1,3,3-tetraphenyldisilazine.

[0026] In the above technical solution, preferably, the molar ratios of silicon source II, aluminum source II, water, template agent II, and organic matter II in step (c) are as follows: silicon source II: aluminum source II: water: template agent II: organic matter II = 1:(0.0025-0.025):(8-20):(0.1-0.3):(0.005-0.20), and the ratio of the mass of the mixture B to the total mass of the five substances silicon source II, aluminum source II, water, template agent II, and organic matter II is (0.04-0.22):1, wherein silicon source II and aluminum source II are calculated as SiO2 and Al2O3, respectively.

[0027] In the above technical solution, preferably, the crystallization conditions in step (d) are crystallization at 130-180℃ for 12-60 hours under sealed conditions.

[0028] The second aspect of the present invention provides a ZSM-5 molecular sieve prepared by the preparation method of the first aspect.

[0029] In the above technical solution, the initial static water contact angle of the molecular sieve is 110-160°, and the static benzene adsorption capacity is 180-230 mg / g.

[0030] In the above technical solution, preferably, the b-axis thickness of the ZSM-5 molecular sieve is 10-95 nm, more preferably 30-90 nm, and the exposure of the crystal plane perpendicular to the b-axis is 67%-78%, more preferably 65%-76%.

[0031] In the above technical solution, preferably, the SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 40-400.

[0032] A third aspect of the present invention provides a catalyst for the alkylation of benzene to ethylbenzene, the catalyst comprising ZSM-5 molecular sieve, wherein the synthesized state of the ZSM-5 molecular sieve is the molecular sieve prepared by the method of the first aspect.

[0033] In the above technical solution, the ZSM-5 molecular sieve in the catalyst exists in a calcined state.

[0034] In the above technical solution, the catalyst may optionally include alumina, silicon dioxide, or a mixture thereof, in addition to molecular sieves.

[0035] In the above technical solution, preferably, the catalyst may further include alumina, and based on the mass of the catalyst, the molecular sieve content is above 80%, preferably 80%-90%, and the alumina content is below 20%, preferably 10%-20%.

[0036] In the above technical solution, preferably, the micropore volume of the catalyst is 0.12-0.16 cm³. 3 ·g -1 The mesopore volume is 0.42-0.80 cm³. 3 ·g -1 Its mechanical strength is 70-110 N / cm, and its bulk density is 0.51-0.65 g·cm³. -3 .

[0037] A fourth aspect of this invention provides a method for preparing a catalyst for the alkylation of benzene to ethylbenzene, comprising:

[0038] (e) The ZSM-5 molecular sieve, alumina and polymer mixture prepared in the first aspect are mixed and shaped, and then dried, calcined, subjected to ammonium exchange, steam treatment and acid washing to obtain the catalyst.

[0039] In the above technical solution, preferably, step (e) has one or more of the following features:

[0040] In the above technical solution, preferably, the alumina in step (e) is alumina monohydrate;

[0041] In the above technical solution, preferably, the polymer mixture in step (e) is a mixture of starch and at least one substance selected from hexadecyltrimethylammonium bromide, P123 or F127, wherein the mass ratio of starch to the polymer mixture is 60%-70%.

[0042] In the above technical solution, preferably, in step (e), the mass ratio of molecular sieve, alumina and polymer mixture is: molecular sieve: alumina: polymer mixture = 1:(0.1-0.3):(0.05-0.1);

[0043] In the above technical solution, preferably, a molding aid, such as at least one of dilute nitric acid and guar gum powder, can be added in step (e);

[0044] In the above technical solution, preferably, in step (e), the dilute nitric acid is preferably an aqueous solution of nitric acid with a mass concentration of 1.5%-7%;

[0045] In the above technical solution, preferably, the mass ratio of molecular sieve, dilute nitric acid, and guar gum powder in step (e) is: molecular sieve: dilute nitric acid: guar gum powder = 1:(0.8-1.0):(0.03-0.05);

[0046] In the above technical solution, preferably, the molding in step (e) is extrusion molding, followed by drying, calcination, ammonium exchange, steam treatment, and acid washing.

[0047] In the above technical solution, preferably, in step (e), the drying conditions are: drying at 120-150℃ for 5-15 hours; calcination conditions are: calcination at 400-600℃ for 4-10 hours; ammonium exchange conditions are: treatment with an ammonium salt solution with a mass concentration of 2%-8% at 20-90℃ for 2-5 hours, repeated 4 times, wherein the ammonium salt is one of ammonium sulfate, ammonium chloride, ammonium acetate, or ammonium nitrate; steam treatment conditions are: treatment at 420-520℃ for 4-10 hours in a saturated steam atmosphere; and acid washing conditions are: treatment with an acid solution with a mass concentration of 0.5%-3.0% at 20-90℃ for 2-5 hours, wherein the acid is at least one of hydrochloric acid, sulfuric acid, nitric acid, or oxalic acid.

[0048] The fifth aspect of the present invention provides a catalyst for the alkylation of benzene to ethylbenzene prepared by the method of the fourth aspect.

[0049] In the above technical solution, preferably, the catalyst, based on the mass of the catalyst, has a molecular sieve content of 80% or more, preferably 80%-90%, and an alumina content of 20% or less, preferably 10%-20%.

[0050] In the above technical solution, preferably, the micropore volume of the catalyst is 0.12-0.16 cm³. 3 ·g -1 The mesopore volume is 0.42-0.80 cm³. 3 ·g -1 Its mechanical strength is 70-110 N / cm, and its bulk density is 0.51-0.65 g·cm³. -3 .

[0051] The sixth aspect of the present invention provides a method for producing ethylbenzene by benzene alkylation, wherein the reaction raw materials benzene and ethylene are contacted with the above-mentioned ZSM-5 molecular sieve catalyst to generate ethylbenzene.

[0052] In the above technical solution, preferably, the ethylene mass concentration in the ethylene feedstock is 8%-100%.

[0053] In the above technical solution, preferably, the reaction temperature is 300-380℃, the reaction pressure is 0.4-2.5MPa, and the ethylene mass hourly space velocity is 0.1-3.0h. -1 The molar ratio of benzene to ethylene is 4.0-6.0.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] 1. The inventors of this invention have discovered through research that when the initial static water contact angle of ZSM-5 molecular sieve is in the range of 110-160°, the outer surface is hydrophobic, and the static benzene adsorption capacity is 180-230 mg / g, the condensation of the binder and the silanol groups on the surface of the molecular sieve can be effectively inhibited during the molding process, reducing the pore-blocking effect of the binder, increasing the pore volume of the catalyst, which is beneficial to improving the overall performance of the catalyst, especially extending the catalyst's lifespan in the alkylation reaction of benzene and ethylene to ethylbenzene.

[0056] 2. The inventors of this invention discovered that the b-axis thickness and the exposure of the crystal plane perpendicular to the b-axis direction of ZSM-5 molecular sieve are crucial to the performance of the benzene alkylation catalyst. Since the crystal growth process of ZSM-5 molecular sieve follows the Ostwald-ripening and Wulff construction rules, ZSM-5 molecular sieves prepared by conventional methods often exhibit a coffin morphology, making it difficult to control the b-axis thickness and the exposure of the crystal plane perpendicular to the b-axis direction. Further research by the inventors revealed that by introducing silanes containing aminopropyl groups and silanes containing phenyl groups at different times during the molecular sieve preparation process, and controlling the two closed-loop treatment conditions, the b-axis thickness of the molecular sieve can be effectively controlled to be 10-95 nm, preferably 30-90 nm, and the exposure of the crystal plane perpendicular to the b-axis direction to be 67%-78%, preferably 65%-76%. The ZSM-5 molecular sieve of this invention, when used in the benzene alkylation to ethylbenzene reaction, significantly improves ethylene conversion, suppresses side reactions, increases the ethyl selectivity in the alkylation product, and extends catalyst lifetime, making it particularly suitable for the benzene alkylation to ethylbenzene reaction. Attached Figure Description

[0057] Figure 1 The XRD pattern of the molecular sieve prepared in Example 1 of this invention;

[0058] Figure 2 A photograph of the static water initial contact angle of the molecular sieve prepared in Example 1 of this invention;

[0059] Figure 3 The XRD pattern of the molecular sieve prepared in Comparative Example 1 of this invention is shown.

[0060] Figure 4 This is a photograph of the static water initial contact angle of the molecular sieve prepared in Comparative Example 1 of the present invention. Detailed Implementation

[0061] The present invention will now be described in detail with reference to specific embodiments, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0062] In this invention, the b-axis thickness of the molecular sieve and the exposure of the crystal planes perpendicular to the b-axis direction are obtained by analyzing SEM images. SEM images were obtained using a Hitachi S-4800 cold field emission high-resolution scanning electron microscope. The exposure of the crystal planes perpendicular to the b-axis direction is defined as the proportion of the area of ​​the 010 crystal plane of the ZSM-5 molecular sieve to the total area of ​​all crystal planes.

[0063] In this invention, the micropore volume and mesopore volume are obtained by nitrogen adsorption-desorption test. The nitrogen adsorption-desorption isotherm of the catalyst is tested at liquid nitrogen temperature using a BEL-MAX specific surface area and pore size analyzer manufactured by BELSORP Corporation of Japan. The total pore volume is calculated using the BET equation, and the micropore volume is calculated using the t-plot method. The difference between the total pore volume and the micropore volume is the mesopore volume.

[0064] In this invention, the mechanical strength is obtained using an intelligent particle strength tester. The DLIII type intelligent particle strength tester from Dalian Penghui Technology Development Co., Ltd. is used to test the mechanical strength of the catalyst. The length of the catalyst is 5mm, and it is placed horizontally on the tester. The maximum pressure that the catalyst can withstand when it is crushed is tested. The average value is taken after testing the crushing strength of 20 catalysts.

[0065] In this invention, the XRD pattern of the catalyst was obtained using a Rigaku Ultima IV X-ray powder diffractometer (Japan). The voltage was set to 35 kV, the current to 30 mA, and the scan rate to 1°·min. -1 .

[0066] In this invention, the bulk density of the catalyst is tested using a 1000mL graduated cylinder. The actual weight of the added catalyst (in grams) is divided by the actual volume, and the unit is g·cm³. -3 .

[0067] In this invention, the SiO2 / Al2O3 molar ratio is obtained by ICP testing. A Kontron Model S-35 ICP-AES analyzer is used to perform the ICP test to obtain the silicon-to-aluminum ratio data.

[0068] In this invention, the static water initial contact angle of the molecular sieve is measured using the Chengde Dingsheng JY-82C video contact angle measuring instrument. An appropriate amount of ground powder sample is placed in a tablet press and pressed into a tablet shape, then placed on the contact angle testing platform. Water droplets are added using the automatic titration system of the equipment, test photos are taken, and then the contact angle is measured using the protractor method.

[0069] In this invention, the static benzene adsorption capacity was tested using a BSD-VVS multi-station gravimetric gas vapor adsorption instrument from Best Instruments Technology Co., Ltd. Before the test, the sample was activated at 250°C for 6 hours under vacuum conditions. The cumulative adsorption capacity of the sample for benzene when the relative pressure P / P0 was 0.90 was taken as the final static benzene adsorption capacity.

[0070]

Example 1

[0071] This embodiment is used to synthesize a ZSM-5 molecular sieve and a ZSM-5 molecular sieve catalyst. The specific preparation process is as follows:

[0072] 416.6 g of tetraethyl silicate, 20 g of aluminum sulfate octadechydrate, 576 g of water, and 122 g of tetrapropylammonium hydroxide were mixed evenly and then stirred at 30 °C for 10 hours under sealed conditions to obtain mixture A1. Then, 74.8 g of diethylenetriaminopropylmethyldimethoxysilane was added to mixture A1 and mixed evenly. The mixture was stirred at 110 °C for 2 hours under sealed conditions to obtain mixture B1. The molar ratio of tetraethyl silicate (SiO2): aluminum sulfate octadechydrate (Al2O3): water: tetrapropylammonium hydroxide: diethylenetriaminopropylmethyldimethoxysilane was 1:0.015:16:0.3:0.15. Mixture C1 was obtained by mixing 69.3 g of mixture B1, 120 g of silicon powder, 20 g of aluminum sulfate octadechydrate, 468 g of water, 44.1 g of butanediamine, and 41 g of 1,3-diphenyltetraethyldisilazane. The molar ratio of silicon powder (SiO2): aluminum sulfate octadechydrate (Al2O3): water: n-butylamine: 1,3-diphenyltetraethyldisilazane was 1:0.015:13:0.25:0.06. C1 was crystallized in a sealed container at 165 °C for 36 h. The resulting solid was then centrifuged and washed repeatedly with deionized water until the pH of the washing solution reached 7.0. Finally, the washed solid was dried at 150 °C for 8 h to obtain molecular sieve D1.

[0073] Catalyst E1 was obtained by mixing 1000 g of molecular sieve D1, 200 g of alumina monohydrate, 950 g of 3.5% nitric acid aqueous solution, 45 g of guar gum powder, and 80 g of polymer mixture (including 52 g of starch and 28 g of hexadecyltrimethylammonium bromide) and extruding it into a cylindrical shape. Then, the mixture was treated with 135 °C for 10 hours, 520 °C for 4 hours, 5% ammonium chloride solution at 70 °C for 2 hours, and this process was repeated 4 times. The mixture was then treated with 490 °C in a saturated steam atmosphere for 7 hours, and finally treated with 1.5% oxalic acid solution at 70 °C for 4 hours.

[0074] The XRD pattern of molecular sieve D1 is as follows: Figure 1As shown, it exhibits typical ZSM-5 molecular sieve diffraction peaks. The static water initial contact angle photograph of molecular sieve D1 is shown below. Figure 2 As shown, the value is 133.5°, and the static benzene adsorption capacity is 210 mg / g. The b-axis thickness of the molecular sieve is 75 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 72%. The SiO2 / Al2O3 molar ratio of molecular sieve D1 is 66.

[0075] The micropore volume of catalyst E1 was determined to be 0.14 cm³. 3 ·g -1 The mesopore volume is 0.63 cm³. 3 ·g -1 Its mechanical strength is 95 N / cm, and its bulk density is 0.54 g·cm³. -3 .

[0076]

Example 2

[0077] This embodiment is used to synthesize a ZSM-5 molecular sieve and a ZSM-5 molecular sieve catalyst. The specific preparation process is as follows:

[0078] 264.4 g of tetrapropyl silicate, 16.67 g of aluminum sulfate octadechydrate, 360 g of water, and 45.1 g of ethylamine were mixed evenly and then stirred at 40°C for 5 hours under sealed conditions to obtain mixture A2. Then, 70.3 g of N-aminoethyl-3-aminopropylmethyldiethoxysilane was added to mixture A2 and mixed evenly. The mixture was stirred at 130°C for 1 hour under sealed conditions to obtain mixture B2. The molar ratio of tetrapropyl silicate (SiO2): aluminum sulfate octadechydrate (Al2O3): water: ethylamine: N-aminoethyl-3-aminopropylmethyldiethoxysilane was 1:0.025:20:1.0:0.3. Mixture C2 was obtained by mixing 119.4 g of mixture B2, 60 g of silica, 16.67 g of aluminum sulfate octadecylhydrate, 360 g of water, 61 g of tetrapropylammonium hydroxide, and 67.5 g of 1,3-dichloro-1,1,3,3-tetraphenyldisilazane. The molar ratio of silica (SiO2): aluminum sulfate octadecylhydrate (Al2O3): water: tetrapropylammonium hydroxide: 1,3-dichloro-1,1,3,3-tetraphenyldisilazane was 1:0.025:20:0.3:0.15. C2 was crystallized in a sealed container at 180 °C for 12 h. The resulting solid was then centrifuged and washed repeatedly with deionized water until the pH of the washing solution reached 7.0. The washed solid was then dried at 150 °C for 8 h to obtain molecular sieve D2.

[0079] Catalyst E2 was obtained by mixing 1000g of molecular sieve D2, 300g of alumina monohydrate, 1000g of 7% nitric acid aqueous solution, 50g of guar gum powder, and 100g of polymer mixture (including 70g of starch and 30g of P123) and extruding it into a four-leaf clover shape. Then, the mixture was treated with 150℃ for 5 hours, 600℃ for 4 hours, 8% ammonium nitrate solution at 90℃ for 3 hours, and this process was repeated 4 times. The mixture was then treated with 520℃ in a saturated steam atmosphere for 10 hours and finally treated with 3.0% nitric acid solution at 90℃ for 2 hours.

[0080] The XRD pattern of molecular sieve D2 exhibits typical diffraction peaks characteristic of ZSM-5 molecular sieves. The static initial contact angle of molecular sieve D2 with water is 155.6°, and the static benzene adsorption capacity is 185 mg / g. The b-axis thickness of the molecular sieve is 35 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 75%. The SiO2 / Al2O3 molar ratio of molecular sieve D2 is 42.

[0081] The micropore volume of catalyst E2 was determined to be 0.13 cm³. 3 ·g -1 The mesopore volume is 0.78 cm³. 3 ·g -1 Its mechanical strength is 105 N / cm, and its bulk density is 0.62 g·cm³. -3 .

[0082]

Example 3

[0083] This embodiment is used to synthesize a ZSM-5 molecular sieve and a ZSM-5 molecular sieve catalyst. The specific preparation process is as follows:

[0084] 208.3 g of tetraethyl silicate, 1.02 g of aluminum isopropoxide, 90 g of water, and 8.5 g of piperidine were mixed evenly and then stirred at 10 °C for 15 hours under sealed conditions to obtain mixture A3. Then, 7 g of N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane was added to mixture A3 and mixed evenly. The mixture was stirred at 80 °C for 5 hours under sealed conditions to obtain mixture B3. The molar ratio of tetraethyl silicate (SiO2): aluminum isopropoxide (Al2O3): water: piperidine: N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane was 1:0.0025:5:0.1:0.02. Mixture C3 was obtained by mixing 14.7 g of mixture B3, 208.3 g of tetraethyl silicate, 1.67 g of aluminum sulfate octadecahydrate, 144 g of water, 11.6 g of hexamethylenediamine, and 2.1 g of 1,3-dimethyl-1,1,3,3-tetraphenyldisilazane, where tetraethyl silicate (calculated as SiO2), aluminum sulfate octadecahydrate (calculated as Al2O3), and water:hexamethylenediamine:1,3-dimethyl-1,1,3,3-tetraphenyldisilazane = 1:0.0025:8:0.1:0.005 (molar ratio). C3 was crystallized in a sealed container at 130 °C for 60 h, then centrifuged to obtain a solid. The solid was washed repeatedly with deionized water until the pH of the washing solution reached 7.0. The washed solid was then dried at 150 °C for 8 h to obtain molecular sieve D3.

[0085] Catalyst E3 was obtained by mixing 1000g of molecular sieve D3, 100g of alumina monohydrate, 800g of 1.5% nitric acid aqueous solution, 30g of guar gum powder, and 50g of polymer mixture (including 30g of starch and 20g of hexadecyltrimethylammonium bromide) and extruding the mixture into a cylindrical shape. The mixture was then subjected to the following steps: treatment at 120℃ for 15 hours; treatment at 400℃ for 10 hours; treatment at 20℃ for 5 hours with a 2% ammonium chloride solution, repeated four times; treatment at 420℃ for 10 hours in a saturated steam atmosphere; and treatment at 20℃ for 5 hours with a 0.5% sulfuric acid solution.

[0086] The XRD pattern of molecular sieve D3 exhibits typical diffraction peaks characteristic of ZSM-5 molecular sieves. The static initial contact angle of molecular sieve D3 with water is 110.2°, and the static benzene adsorption capacity is 230 mg / g. The b-axis thickness of the molecular sieve is 87 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 70%. The SiO2 / Al2O3 molar ratio of molecular sieve D3 is 398.

[0087] The micropore volume of catalyst E3 was determined to be 0.16 cm³. 3 ·g -1 The mesopore volume is 0.43 cm³. 3 ·g -1Its mechanical strength is 72 N / cm, and its bulk density is 0.52 g·cm³. -3 .

[0088] Comparative Example 1

[0089] Compared with Example 1, the only difference is that diethylenetriaminepropylmethyldimethoxysilane was not added. The specific preparation process of ZSM-5 molecular sieve and ZSM-5 molecular sieve catalyst is as follows:

[0090] 416.6 g of tetraethyl silicate, 20 g of aluminum sulfate octadechydrate, 576 g of water and 122 g of tetrapropylammonium hydroxide were mixed evenly, and then stirred at 30 °C for 10 hours under sealed conditions to obtain mixture dA1; then stirred at 110 °C for 2 hours under sealed conditions to obtain mixture dB1, wherein the ratio of tetraethyl silicate (calculated as SiO2), aluminum sulfate octadechydrate (calculated as Al2O3), and water to tetrapropylammonium hydroxide is 1:0.015:16:0.3 (molar ratio). Mixture dC1 was obtained by mixing 69.3 g of mixture dB1, 120 g of silicon powder, 20 g of aluminum sulfate octadecylhydrate, 468 g of water, 44.1 g of butanediamine, and 41 g of 1,3-diphenyltetraethyldisilazane. The molar ratio of silicon powder (SiO2): aluminum sulfate octadecylhydrate (Al2O3): water: n-butylamine: 1,3-diphenyltetraethyldisilazane was 1:0.015:13:0.25:0.06. dC1 was crystallized in a sealed container at 165 °C for 36 h. The resulting solid was then centrifuged and washed repeatedly with deionized water until the pH of the washing solution reached 7.0. The washed solid was then dried at 150 °C for 8 h to obtain molecular sieve dD1.

[0091] Catalyst dE1 was obtained by mixing 1000 g of molecular sieve dD1, 200 g of alumina monohydrate, 950 g of 3.5% nitric acid aqueous solution, 45 g of guar gum powder, and 80 g of polymer mixture (including 52 g of starch and 28 g of hexadecyltrimethylammonium bromide) and extruding it into a cylindrical shape. Then, the mixture was treated with 135 °C for 10 hours, 520 °C for 4 hours, 5% ammonium chloride solution at 70 °C for 2 hours, and this process was repeated 4 times. The mixture was then treated with 490 °C in a saturated steam atmosphere for 7 hours, and finally treated with 1.5% oxalic acid solution at 70 °C for 4 hours.

[0092] The XRD pattern of molecular sieve dD1 is as follows: Figure 3 As shown, it exhibits typical ZSM-5 molecular sieve diffraction peaks. A photograph of the static water initial contact angle of molecular sieve dD1 is shown below. Figure 4As shown, the value is 44.2°, and the static benzene adsorption capacity is 145 mg / g. The b-axis thickness of the molecular sieve is 148 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 45%. The SiO2 / Al2O3 molar ratio of molecular sieve dD1 is 65.

[0093] The micropore volume of catalyst dE1 was determined to be 0.11 cm³. 3 ·g -1 The mesopore volume is 0.61 cm³. 3 ·g -1 Its mechanical strength is 92 N / cm, and its bulk density is 0.55 g·cm³. -3 .

[0094] Comparative Example 2

[0095] Compared with Example 1, the only difference is that 1,3-diphenyltetraethyldisilazane was not added. The specific preparation process of ZSM-5 molecular sieve and ZSM-5 molecular sieve catalyst is as follows:

[0096] 416.6 g of tetraethyl silicate, 20 g of aluminum sulfate octadechydrate, 576 g of water, and 122 g of tetrapropylammonium hydroxide were mixed evenly and then stirred at 30 °C for 10 hours under sealed conditions to obtain mixture dA2. Then, 74.8 g of diethylenetriaminopropylmethyldimethoxysilane was added to the above mixture dA2 and mixed evenly. The mixture was stirred at 110 °C for 2 hours under sealed conditions to obtain mixture dB2. In the mixture, the ratio of tetraethyl silicate (SiO2) to aluminum sulfate octadechydrate (Al2O3) to water to tetrapropylammonium hydroxide to diethylenetriaminopropylmethyldimethoxysilane was 1:0.015:16:0.3:0.15 (molar ratio). Mixture dC2 was obtained by mixing 69.3 g of dB2, 120 g of silicon powder, 20 g of aluminum sulfate octadechydrate, 468 g of water, and 44.1 g of butanediamine. The molar ratio of silicon powder (SiO2), aluminum sulfate octadechydrate (Al2O3), water, and n-butylamine was 1:0.015:13:0.25. dC2 was crystallized in a sealed container at 165 °C for 36 h. The resulting solid was then centrifuged and washed repeatedly with deionized water until the pH of the washing solution reached 7.0. The washed solid was then dried at 150 °C for 8 h to obtain molecular sieve dD2.

[0097] The catalyst dE2 was obtained by mixing 1000 g of molecular sieve dD2, 200 g of alumina monohydrate, 950 g of 3.5% nitric acid aqueous solution, 45 g of guar gum powder, and 80 g of polymer mixture (including 52 g of starch and 28 g of hexadecyltrimethylammonium bromide) and extruding it into a cylindrical shape. Then, the mixture was treated with 135 °C for 10 hours, 520 °C for 4 hours, 5% ammonium chloride solution at 70 °C for 2 hours, and this process was repeated 4 times. The mixture was then treated with 490 °C in a saturated steam atmosphere for 7 hours and 1.5% oxalic acid solution at 70 °C for 4 hours.

[0098] The XRD pattern of molecular sieve dD2 exhibits typical ZSM-5 molecular sieve diffraction peaks. The static initial contact angle of molecular sieve dD2 with water is 41.5°, and the static benzene adsorption capacity is 124 mg / g. The b-axis thickness of the molecular sieve is 163 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 62%. The SiO2 / Al2O3 molar ratio of molecular sieve dD2 is 66.

[0099] The micropore volume of catalyst dE2 was determined to be 0.10 cm³. 3 ·g -1 The mesopore volume is 0.59 cm³. 3 ·g -1 Its mechanical strength is 94 N / cm, and its bulk density is 0.53 g·cm³. -3 .

[0100] Comparative Example 3

[0101] Compared with Example 1, the only difference is that equimolar amounts of 1,3-diphenyltetraethyldisilazane are used instead of diethylenetriaminepropylmethyldimethoxysilane. The specific preparation process of ZSM-5 molecular sieve and ZSM-5 molecular sieve catalyst is as follows:

[0102] 416.6 g of tetraethyl silicate, 20 g of aluminum sulfate octadechydrate, 576 g of water, and 122 g of tetrapropylammonium hydroxide were mixed evenly and then stirred at 30 °C for 10 hours under sealed conditions to obtain mixture dA3. Then, 102.5 g of 1,3-diphenyltetraethyldisilazane was added to the above mixture dA3 and mixed evenly. The mixture was stirred at 110 °C for 2 hours under sealed conditions to obtain mixture dB3. In the mixture, the ratio of tetraethyl silicate (SiO2): aluminum sulfate octadechydrate (Al2O3): water: tetrapropylammonium hydroxide: 1,3-diphenyltetraethyldisilazane = 1:0.015:16:0.3:0.15 (molar ratio). Mixture dC3 was obtained by mixing 69.3 g of dB3, 120 g of silicon powder, 20 g of aluminum sulfate octadecylhydrate, 468 g of water, 44.1 g of butanediamine, and 41 g of 1,3-diphenyltetraethyldisilazane. The molar ratio of silicon powder (SiO2): aluminum sulfate octadecylhydrate (Al2O3): water: n-butylamine: 1,3-diphenyltetraethyldisilazane was 1:0.015:13:0.25:0.06. dC3 was crystallized in a sealed container at 165 °C for 36 h. The solid was then obtained by centrifugation and washed repeatedly with deionized water until the pH of the washing solution reached 7.0. The washed solid was then dried at 150 °C for 8 h to obtain molecular sieve dD3.

[0103] The catalyst dE3 was obtained by mixing 1000 g of molecular sieve dD3, 200 g of alumina monohydrate, 950 g of 3.5% nitric acid aqueous solution, 45 g of guar gum powder, and 80 g of polymer mixture (including 52 g of starch and 28 g of hexadecyltrimethylammonium bromide) and extruding it into a cylindrical shape. Then, the mixture was treated with 135 °C for 10 hours, 520 °C for 4 hours, 5% ammonium chloride solution at 70 °C for 2 hours, and this process was repeated 4 times. The mixture was then treated with 490 °C in a saturated steam atmosphere for 7 hours and 1.5% oxalic acid solution at 70 °C for 4 hours.

[0104] The XRD pattern of molecular sieve dD3 exhibits typical ZSM-5 molecular sieve diffraction peaks. The static initial contact angle of molecular sieve dD3 with water is 43.6°, and the static benzene adsorption capacity is 128 mg / g. The b-axis thickness of the molecular sieve is 152 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 51%. The SiO2 / Al2O3 molar ratio of molecular sieve dD3 is 66.

[0105] The micropore volume of catalyst dE3 was determined to be 0.10 cm³. 3 ·g -1 The mesopore volume is 0.58 cm³. 3 ·g -1 Its mechanical strength is 96 N / cm, and its bulk density is 0.54 g·cm³. -3 .

[0106] Comparative Example 4

[0107] Compared with Example 1, the only difference is that 1,3-diphenyltetraethyldisilazane is replaced with an equimolar amount of diethylenetriaminepropylmethyldimethoxysilane. The specific preparation process of ZSM-5 molecular sieve and ZSM-5 molecular sieve catalyst is as follows:

[0108] 416.6 g of tetraethyl silicate, 20 g of aluminum sulfate octadechydrate, 576 g of water, and 122 g of tetrapropylammonium hydroxide were mixed evenly and then stirred at 30 °C for 10 hours under sealed conditions to obtain mixture dA4. Then, 74.8 g of diethylenetriaminopropylmethyldimethoxysilane was added to the above mixture dA4 and mixed evenly. The mixture was stirred at 110 °C for 2 hours under sealed conditions to obtain mixture dB4. In the mixture, the ratio of tetraethyl silicate (SiO2) to aluminum sulfate octadechydrate (Al2O3) to water to tetrapropylammonium hydroxide to diethylenetriaminopropylmethyldimethoxysilane was 1:0.015:16:0.3:0.15 (molar ratio). Mixture dC4 was obtained by mixing 69.3 g of dB4, 120 g of silicon powder, 20 g of aluminum sulfate octadechydrate, 468 g of water, 44.1 g of butanediamine, and 29.9 g of diethylenetriaminopropylmethyldimethoxysilane. The molar ratio of silicon powder (SiO2): aluminum sulfate octadechydrate (Al2O3): water: n-butylamine: diethylenetriaminopropylmethyldimethoxysilane was 1:0.015:13:0.25:0.06. dC4 was crystallized in a sealed container at 165 °C for 36 h. The resulting solid was then centrifuged and washed repeatedly with deionized water until the pH of the washing solution reached 7.0. The washed solid was then dried at 150 °C for 8 h to obtain molecular sieve dD4.

[0109] The catalyst dE4 was obtained by mixing 1000 g of molecular sieve dD4, 200 g of alumina monohydrate, 950 g of 3.5% nitric acid aqueous solution, 45 g of guar gum powder, and 80 g of polymer mixture (including 52 g of starch and 28 g of hexadecyltrimethylammonium bromide) and extruding it into a cylindrical shape. Then, the mixture was treated with 135 °C for 10 hours, 520 °C for 4 hours, 5% ammonium chloride solution at 70 °C for 2 hours, and this process was repeated 4 times. The mixture was then treated with 490 °C in a saturated steam atmosphere for 7 hours and finally treated with 1.5% oxalic acid solution at 70 °C for 4 hours.

[0110] The XRD pattern of molecular sieve dD4 exhibits typical ZSM-5 molecular sieve diffraction peaks. The static initial contact angle of molecular sieve dD4 with water is 41.6°, and the static benzene adsorption capacity is 115 mg / g. The b-axis thickness of the molecular sieve is 178 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 60%. The SiO2 / Al2O3 molar ratio of molecular sieve dD4 is 66.

[0111] The micropore volume of catalyst dE4 was determined to be 0.09 cm³. 3 ·g -1 The mesopore volume is 0.56 cm³. 3 ·g -1 Its mechanical strength is 93 N / cm, and its bulk density is 0.53 g·cm³. -3 .

[0112] Comparative Example 5

[0113] The only difference from Example 1 is that the temperatures for the first and second sealing treatments are the same.

[0114] 416.6 g of tetraethyl silicate, 20 g of aluminum sulfate octadechydrate, 576 g of water, and 122 g of tetrapropylammonium hydroxide were mixed evenly and then stirred at 110 °C for 10 hours under sealed conditions to obtain mixture dA5. Then, 74.8 g of diethylenetriaminopropylmethyldimethoxysilane was added to the above mixture dA5 and mixed evenly. The mixture was stirred at 110 °C for 2 hours under sealed conditions to obtain mixture dB5. In the mixture, the ratio of tetraethyl silicate (SiO2) to aluminum sulfate octadechydrate (Al2O3) to water to tetrapropylammonium hydroxide to diethylenetriaminopropylmethyldimethoxysilane was 1:0.015:16:0.3:0.15 (molar ratio). Mixture dC5 was obtained by mixing 69.3 g of dB5, 120 g of silicon powder, 20 g of aluminum sulfate octadechydrate, 468 g of water, 44.1 g of butanediamine, and 41 g of 1,3-diphenyltetraethyldisilazane. The molar ratio of silicon powder (SiO2): aluminum sulfate octadechydrate (Al2O3): water: n-butylamine: 1,3-diphenyltetraethyldisilazane was 1:0.015:13:0.25:0.06. dC5 was crystallized in a sealed container at 165 °C for 36 h. The resulting solid was then centrifuged and washed repeatedly with deionized water until the pH of the washing solution reached 7.0. Finally, the washed solid was dried at 150 °C for 8 h to obtain molecular sieve dD5.

[0115] The catalyst dE5 was obtained by mixing 1000 g of molecular sieve dD5, 200 g of alumina monohydrate, 950 g of 3.5% nitric acid aqueous solution, 45 g of guar gum powder, and 80 g of polymer mixture (including 52 g of starch and 28 g of hexadecyltrimethylammonium bromide) and extruding it into a cylindrical shape. Then, the catalyst dE5 was obtained by the following steps: treatment at 135°C for 10 hours; treatment at 520°C for 4 hours; treatment at 70°C for 2 hours with 5% ammonium chloride solution, repeated 4 times; treatment at 490°C for 7 hours in a saturated water vapor atmosphere; and treatment at 70°C for 4 hours with 1.5% oxalic acid solution.

[0116] The XRD pattern of molecular sieve dD5 exhibits typical ZSM-5 molecular sieve diffraction peaks. The static initial contact angle of molecular sieve dD5 with water is 92.3°, and the static benzene adsorption capacity is 165 mg / g. The b-axis thickness of the molecular sieve is 220 nm, and the exposure of the crystal plane perpendicular to the b-axis direction is 58%. The SiO2 / Al2O3 molar ratio of molecular sieve dD5 is 66.

[0117] The micropore volume of catalyst dE5 was determined to be 0.09 cm³. 3 ·g -1 The mesopore volume is 0.52 cm³. 3 ·g -1 Its mechanical strength is 97 N / cm, and its bulk density is 0.54 g·cm³. -3 .

[0118]

Examples 4-6

[0119] Catalysts E1-E3 prepared in Examples 1-3 were applied to the benzene alkylation reaction to ethylbenzene, wherein the ethylene mass concentration was 70%, the reaction temperature was 320°C, the pressure was 2.2 MPa, and the ethylene mass hourly space velocity was 3 h⁻¹. -1 The test was conducted under the condition that the molar ratio of benzene to ethylene was 5.2. The ethylene conversion rate and the ethyl selectivity in the alkylation product were tested. The test results are shown in Table 1.

[0120] The catalysts E1-E3 prepared in Examples 1-3 were tested for their single-pass lifetime in the benzene alkylation to ethylbenzene reaction under ultra-high ethylene space velocity (UHSV) conditions, with an ethylene mass concentration of 70%, a reaction temperature of 320°C, a pressure of 2.2 MPa, and an ethylene mass space velocity of 8 h⁻¹. -1 The test was conducted under the condition that the molar ratio of benzene to ethylene was 5.2. The single-pass lifetime refers to the time elapsed from the start of the reaction until the ethylene conversion rate drops to 50% of the initial conversion rate. The test results are shown in Table 1.

[0121] Comparative Examples 6-10

[0122] Catalysts dE1-dE5 prepared in Comparative Examples 1-5 were applied to the benzene alkylation reaction to ethylbenzene, wherein the ethylene mass concentration was 70%, the reaction temperature was 320℃, the pressure was 2.2 MPa, and the ethylene mass hourly space velocity was 3 h⁻¹. -1 The test was conducted under the condition that the molar ratio of benzene to ethylene was 5.2. The ethylene conversion rate and the ethyl selectivity in the alkylation product were tested. The test results are shown in Table 1.

[0123] The catalysts dE1-dE5 prepared in Comparative Examples 1-5 were tested under ultra-high ethylene space velocity (ESV) reaction conditions in the benzene alkylation to ethylbenzene reaction, with an ethylene mass concentration of 70%, a reaction temperature of 320℃, a pressure of 2.2 MPa, and an ethylene mass hourly space velocity (ESV) of 8 h⁻¹. -1 The test was conducted under the condition that the molar ratio of benzene to ethylene was 5.2. The single-pass lifetime refers to the time elapsed from the start of the reaction until the ethylene conversion rate drops to 50% of the initial conversion rate. The test results are shown in Table 1.

[0124] Table 1 shows the test results of the catalysts obtained in each example.

[0125] Catalyst number Ethylene conversion, wt% Ethyl selectivity, wt% Single-trip lifespan, h E1 99.5 99.7 412 E2 99.6 99.8 423 E3 99.3 99.7 405 dE1 98.6 99.2 315 dE2 98.0 99.0 286 dE3 98.3 98.4 302 dE4 97.8 99.0 278 dE5 97.2 98.9 243

[0126] 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. A method for preparing ZSM-5 molecular sieve, comprising: (a) Silicon source I, aluminum source I, water and template agent I are mixed and subjected to a first sealed treatment to obtain mixture A; (b) Mixture A and organic matter I are mixed and subjected to a second sealing process to obtain mixture B; (c) Mix mixture B, silicon source II, aluminum source II, water, template agent II and organic matter II to obtain mixture C; (d) After crystallization, the mixture C is subjected to liquid-solid separation, washing, and drying to obtain the molecular sieve; The first sealing treatment conditions are: temperature 10-40 ℃, time 5-15 hours; the second sealing treatment conditions are: temperature 80-130 ℃, time 1-5 hours. In step (b), organic compound I is a silane containing aminopropyl groups, wherein the aminopropyl silane is one or more of diethylenetriaminopropylmethyldimethoxysilane, N-aminoethyl-3-aminopropylmethyldiethoxysilane, or N-(3-acryloyloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane; the molar ratio of organic compound I to mixture A, based on SiO2, is organic compound I:SiO2 = (0.02-0.3):1; In step (c), organic compound II is a phenyl-containing disilazane, wherein the phenyl-containing disilazane is one or more of 1,3-diphenyltetraethyldisilazane, 1,3-dichloro-1,1,3,3-tetraphenyldisilazane, or 1,3-dimethyl-1,1,3,3-tetraphenyldisilazane; In step (c), the molar ratios of silicon source II, aluminum source II, water, template agent II, and organic matter II are respectively: silicon source II: aluminum source II: water: template agent II: organic matter II = 1: (0.0025-0.025): (8-20): (0.1-0.3): (0.005-0.20); and / or, the mass ratio of the mixture B to the total mass of the five substances silicon source II, aluminum source II, water, template agent II, and organic matter II is (0.04-0.22): 1, wherein silicon source II and aluminum source II are calculated as SiO2 and Al2O3, respectively.

2. The preparation method according to claim 1, characterized in that: In step (a), silicon source I is one or more of tetraethyl silicate, tetrapropyl silicate, and tetrabutyl silicate; and / or, aluminum source I in step (a) is one or more of aluminum sulfate, aluminum isopropoxide, sodium aluminate, and boehmite; and / or, template agent I in step (a) is one or more of tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-butylamine, butanediamine, hexamethyleneimine, piperidine, piperazine, and homopiperazine.

3. The preparation method according to claim 1, characterized in that: In step (a), the molar ratios of silicon source I, aluminum source I, water and template agent I are as follows: silicon source I: aluminum source I: water: template agent I = 1: (0.0025-0.025): (5-20): (0.1-1.0), where silicon source I and aluminum source I are calculated as SiO2 and Al2O3, respectively.

4. The preparation method according to claim 1, characterized in that: In step (c), silicon source II is one or more of silica sol, silica fume, silica powder, tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, and tetrabutyl silicate; and / or, in step (c), aluminum source II is one or more of aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum isopropoxide, sodium aluminate, and boehmite; and / or, in step (c), template agent II is one or more of tetrapropylammonium bromide, tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-propylamine, propylenediamine, n-butylamine, butylenediamine, n-hexylamine, hexamethylenediamine, ammonia, hexamethyleneimine, piperidine, piperazine, and hyperpiperazine.

5. The preparation method according to claim 1, characterized in that, The crystallization conditions in step (d) are crystallization at 130-180 °C for 12-60 hours under sealed conditions.

6. ZSM-5 molecular sieve prepared by any of the preparation methods described in claims 1-5.

7. The molecular sieve according to claim 6, characterized in that: The molecular sieve has a static water initial contact angle of 110-160° and a static benzene adsorption capacity of 180-230 mg / g.

8. The molecular sieve according to claim 6, characterized in that: The molecular sieve has a b-axis thickness of 10-95 nm and a crystal plane exposure of 67%-78% perpendicular to the b-axis.

9. The molecular sieve according to claim 8, characterized in that: The molecular sieve has a b-axis thickness of 30-90 nm and a crystal plane exposure perpendicular to the b-axis of 65%-76%.

10. The molecular sieve according to claim 6, characterized in that: The SiO2 / Al2O3 molar ratio of the molecular sieve is 40-400.

11. A catalyst for the alkylation of benzene to ethylbenzene, characterized in that: The catalyst comprises ZSM-5 molecular sieve prepared by any one of the preparation methods of claims 1-5, optionally comprising alumina.

12. The catalyst according to claim 11, characterized in that: The catalyst, based on its mass, contains more than 80% molecular sieve and less than 20% alumina.

13. The catalyst according to claim 12, characterized in that: The catalyst, based on its mass, contains 80%-90% molecular sieve and 10%-20% alumina.

14. The catalyst according to claim 11, characterized in that: The catalyst has a micropore volume of 0.12-0.16 cm³. 3 ·g -1 The mesopore volume is 0.42-0.80 cm³. 3 ·g -1 Its mechanical strength is 70-110 N / cm, and its bulk density is 0.51-0.65 g·cm³. -3 .

15. A method for preparing a catalyst for the alkylation of benzene to ethylbenzene, comprising: (d) The ZSM-5 molecular sieve, alumina and polymer mixture prepared by any one of the methods described in claims 1-5 are mixed and shaped, and then dried, calcined, subjected to ammonium exchange, steam treatment and acid washing to obtain the catalyst.

16. The preparation method according to claim 15, characterized in that: In step (e), the alumina is alumina monohydrate; and / or, in step (e), the polymer mixture is a mixture of starch and at least one substance selected from hexadecyltrimethylammonium bromide, P123 or F127, wherein the starch accounts for 60%-70% of the mass of the polymer mixture.

17. The preparation method according to claim 15, characterized in that: In step (e), the mass ratio of molecular sieve, alumina and polymer mixture is: molecular sieve: alumina: polymer mixture = 1: (0.1-0.3): (0.05-0.1).

18. The preparation method according to claim 15, characterized in that: In step (e), the drying conditions are 120-150℃ for 5-15 hours; the calcination conditions are 400-600℃ for 4-10 hours; the steam treatment conditions are 420-520℃ for 4-10 hours in a saturated steam atmosphere; and the pickling conditions are 0.5%-3.0% acid solution at 20-90℃ for 2-5 hours.

19. A method for producing ethylbenzene by benzene alkylation, characterized in that: The reactants benzene and ethylene are contacted with any of the catalysts described in claims 11-14 or any of the catalysts prepared by the methods described in claims 15-18 to generate ethylbenzene.

20. The method according to claim 19, characterized in that: The ethylene feedstock has an ethylene mass concentration of 8%-100%; and / or, the reaction conditions are as follows: reaction temperature of 300-380 ℃, reaction pressure of 0.4-2.5 MPa, and ethylene mass hourly space velocity of 0.1-3.0 h⁻¹. -1 The molar ratio of benzene to ethylene is 4.0-6.0.

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