ZSM-5 molecular sieve, catalyst for preparing ethylbenzene by means of alkylation of benzene, and preparation and use thereof

Abstract

A ZSM-5 molecular sieve, a catalyst for preparing ethylbenzene by means of the alkylation of benzene, and the preparation and use thereof. The ZSM-5 molecular sieve does not have twin crystals; the dimension (La) in the a-axis direction is equal to 240-300 nm, the dimension (Lb) in the b-axis direction is equal to 60-90 nm, and the dimension (Lc) in the c-axis direction is equal to 1500-2200 nm; the dimension (Ld) of a crystal edge formed by the intersection of (010) and (101) crystal planes is equal to 180-220 nm, and the dimension (Le) of a crystal edge formed by the intersection of (010) and (100) crystal planes is equal to 1300-1900 nm; and the ratio (La / Lb) of the dimension in the a-axis direction to the dimension in the b-axis direction is equal to 2.5-4.5, and the ratio (Lc / Lb) of the dimension in the c-axis direction to the dimension in the b-axis direction is equal to 22.0-26.0. When the catalyst for preparing ethylbenzene by means of the alkylation of benzene, which catalyst is prepared from the ZSM-5 molecular sieve, is used in a reaction for ethylbenzene preparation by means of benzene alkylation, the conversion rate of ethylene is high, the selectivity of ethyl is high in an alkylation product, and the mass content of the critical impurity xylene is low.

Description

A ZSM-5 molecular sieve, a catalyst for alkylation of benzene to produce ethylbenzene, and its preparation and application Technical Field

[0001] The present invention belongs to the technical field of catalytic chemistry and chemical engineering, and in particular relates to a ZSM-5 molecular sieve, a benzene alkylation catalyst, and a preparation method and application thereof. Background Art

[0002] Benzene alkylation products such as ethylbenzene are important basic organic raw materials with a wide range of uses and play a vital role in the development of the national economy.

[0003] Benzene-ethylene alkylation to ethylbenzene (EB) utilizes a wide range of raw material sources and can be categorized as either a liquid-phase or vapor-phase process, depending on the reaction process. The vapor-phase process is suitable for a variety of ethylene feedstocks, including pure ethylene, dilute ethylene, or ethanol, with ethylene concentrations ranging from 10 to 100 wt%. Dilute ethylene feedstocks primarily come from tail gases from FCC and DCC units, or crude ethane cracking gas, and are relatively inexpensive compared to polymerization-grade pure ethylene.

[0004] Cheap, dilute ethylene feedstocks contain numerous impurities and produce severe side reactions during the reaction, resulting in reduced selectivity for the ethylbenzene product. The vapor-phase process operates at high reaction temperatures, typically exceeding 300°C. Furthermore, the alkylation of benzene and ethylene is a highly exothermic reaction, significantly increasing the temperature rise in the alkylation reactor, the likelihood of side reactions, and the rate of coking. This significantly increases the content of xylene, a key impurity in the ethylbenzene product, and significantly shortens the catalyst's service life. The key to vapor-phase alkylation of benzene and ethylene to ethylbenzene is developing highly active, selective, and stable alkylation catalysts suitable for a variety of ethylene feedstocks.

[0005] The technology of producing ethylbenzene by vapor-phase alkylation of benzene and ethylene has been widely studied, and the active component of the catalyst used in the vapor-phase alkylation of benzene and ethylene to produce ethylbenzene is generally ZSM-5 molecular sieve.

[0006] Chinese patent application CN102875316A discloses a method for producing ethylbenzene by alkylating dry gas with benzene. This method uses dry gas and benzene as the reactants, which are contacted with a catalyst to undergo a vapor-phase alkylation reaction to produce ethylbenzene. The catalyst comprises the following components, by weight: a) 40-90% ZSM-5 molecular sieve with a crystallite diameter of 5-500 nanometers and a SiO2 / Al2O3 molar ratio of 30-400; b) 9-59% alumina or silica as a binder; and c) 0.1-10% alkaline earth metal oxide and 0.1-10% rare earth metal oxide. This catalyst, treated with high-temperature steam, effectively addresses the issues of poor catalyst stability and short regeneration cycles. However, this method is applicable to dry gas, typically with an ethylene concentration of 10-20 wt.%, and does not specify whether it is applicable to feed gases with higher ethylene concentrations.

[0007] Chinese patent application CN101993331A discloses a method for alkylating pure ethylene or dry gas with benzene to produce ethylbenzene. The method utilizes a fixed-bed reactor loaded with at least one section of ZSM-5 molecular sieve catalyst I having a SiO2 / Al2O3 molar ratio of 50-150 and at least one section of ZSM-5 molecular sieve catalyst II having a SiO2 / Al2O3 molar ratio of 160-300. 30%-70% of the pure ethylene or dry gas enters the bed loaded with catalyst I, and the remainder enters the bed loaded with catalyst II. 80%-100% of the benzene enters the first section of the bed loaded with catalyst I from the top of the reactor, and the remaining benzene enters the subsequent catalyst beds in stages, ensuring that the difference between the inlet temperature of each catalyst bed and the temperature of the stream inlet to the reactor top is controlled to be within ±5°C.

[0008] Chinese patent application CN108080019A discloses a method for preparing a highly selective benzene alkylation catalyst strip. The method uses a high-silicon-aluminum ratio MFI zeolite molecular sieve as the catalyst matrix. The hydrolyzate of acidified silicone grease and the high-silicon-aluminum ratio MFI zeolite molecular sieve are extruded into strips. The extruded catalyst is then treated with the separated mother liquor obtained from hydrothermal crystallization of the high-silicon-aluminum ratio MFI zeolite molecular sieve, to which a boride is added. The extruded strips are then converted into a hydrogen-type alkylation catalyst using an ion exchange method. This method utilizes the mother liquor generated during the hydrothermal synthesis of the high-silicon-aluminum ratio MFI zeolite molecular sieve to treat the extruded catalyst strips. This method not only recovers useful components from the mother liquor and unclogs the catalyst pores, but also reduces environmental pollution throughout the entire alkylation catalyst production chain. The addition of an appropriate amount of boride to the mother liquor during the treatment of the extruded catalyst improves the mechanical strength of the catalyst particles, thereby extending the catalyst's service life. However, this method does not make a detailed comparison of the specific lifespan of the catalyst, and the applicable raw materials are ethanol or methanol, without further explanation on whether it is applicable to dilute ethylene or pure ethylene raw materials.

[0009] Other documents related to background technology include CN111111748A, CN114733560A, CN103073020A, and CN107512729A.

[0010] Therefore, there remains a need to provide benzene alkylation catalysts that exhibit desirable properties.

[0011] Summary of the Invention

[0012] After diligent research, the present inventors have found that the morphology, axial dimensions, and ratios thereof, as well as the crystal face areas and ratios thereof, of ZSM-5 molecular sieves have a significant impact on the performance of benzene alkylation catalysts. Further research by the present inventors has found that, during the molecular sieve preparation process, the introduction of organic matter II and organic matter III at different times can effectively control the morphology, axial dimensions, and ratios of the sheet-like molecular sieves. Furthermore, the areas and ratios of the three crystal faces (100), (010), and (101) are also within a specific range. Furthermore, the prepared ZSM-5 molecular sieve is a novel ZSM-5 molecular sieve that, when used in a benzene alkylation catalyst to produce ethylbenzene, can improve ethylene conversion, increase selectivity of ethyl products in the alkylated product, inhibit side reactions, reduce xylene content, and extend the service life of the catalyst. This has led to the completion of the present invention.

[0013] The first aspect of the present invention provides a ZSM-5 molecular sieve, wherein the molecular sieve has no twins, and the size of the a-axis direction is La = 240-300 nm, for example, 250, 260, 270, 280 or 290 nm, or in the range between any two of the values; the size of the b-axis direction is Lb = 60-90 nm, for example, 65, 70, 75, 80 or 85 nm, or in the range between any two of the values; the size of the c-axis direction is Lc = 1 500-2200nm, for example, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, 2000, 2050, 2100 or 2150nm, or in the range between any two of the values; in the molecular sieve, the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=180-220nm, for example, 185, 190, 195, 200, 205 , 210 or 215 nm, or within the range between any two of the values; the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le = 1300-1900 nm, for example, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800 or 1850 nm, or within the range between any two of the values; in the molecular sieve, the size of the a-axis direction and the b-axis direction is The dimension ratio is La / Lb=2.5-4.5, for example, 2.7, 2.9, 3.1, 3.3, 3.5, 3.7, 3.9, 4.1 or 4.3, or in the range between any two of the values; and the dimension ratio in the c-axis direction to the b-axis direction is Lc / Lb=22.0-26.0, for example, 22.5, 23.0, 23.5, 24.0, 24.5, 25.0 or 25.5, or in the range between any two of the values.

[0014] In some preferred embodiments, the area of ​​the (100) crystal plane in the molecular sieve is S1 = 75,000-180,000 nm. 2 , for example, 80,000, 90,000, 100,000, 110,000, 120,000, 130,000, 140,000, 150,000, 160,000 or 170,000 nm 2 , or within the range between any two of the values; area S2 of the (010) plane = 350,000-600,000 nm 2 , for example 400,000, 450,000, 500,000 or 550,000 nm 2, or within the range between any two of the values; the area of ​​the (101) crystal plane S3 = 10,000-20,000 nm 2 , for example, 11,000, 12,000, 13,000, 14,000, 15,000, 16,000, 17,000, 18,000 or 19,000 nm 2 , or within the range between any two of the values; in the molecular sieve, the area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.20-0.30, for example, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28 or 0.29, or within the range between any two of the values; and the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.025-0.045, for example, 0.027, 0.029, 0.031, 0.033, 0.035, 0.037, 0.039, 0.041 or 0.043. Preferably, in the molecular sieve, the (010) crystal plane exposure is S2 / (S1+S2+2S3)×100%=70%-80%, for example, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78% or 79%.

[0015] In some preferred embodiments, the infrared spectrum of the molecular sieve is in the wave number range of 690-750 cm -1 There are two peaks P1 and P2 in the spectrum, and the wavenumber ranges corresponding to the peaks of P1 and P2 are 690-710 cm -1 and 730-750cm -1 The infrared spectrum of the molecular sieve is in the wave number range of 440-560cm -1 There are two peaks P3 and P4 in the spectrum, and the wavenumber ranges corresponding to the peaks of P3 and P4 are 440-460 cm -1 and 540-560cm -1 .

[0016] In some embodiments, the ZSM-5 molecular sieve has a SiO2:Al2O3 molar ratio of 100-300.

[0017] In some embodiments, the schematic chemical composition of the as-synthesized molecular sieve, measured in moles, includes: SiO2:nAl2O3:mE2:xE3, where E2 is organic compound II, E3 is organic compound III, n is 0.0033-0.01, m is 0.0015-0.005, and x is 0.005-0.1. The as-synthesized molecular sieve refers to the uncalcined state after synthesis. When present in the as-synthesized molecular sieve, it may further contain a template and water. The template may be any template known in the art to give ZSM-5 molecular sieves, such as one or more of tetrapropylammonium bromide, tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-propylamine, propylenediamine, n-butylamine, butylenediamine, n-hexylamine, hexamethylenediamine, aqueous ammonia, hexamethyleneimine, piperidine, and piperazine. The molar ratio of the template to SiO2 may be 0.05-0.3:1. The molar ratio of water to SiO2 can be 3-20:1.

[0018] According to the present disclosure, the structural formula of the organic compound II is Wherein R1-R3 are each independently selected from C1-C6 alkoxy and C1-C6 alkoxy-C1-C6 alkyl, preferably each independently methoxy, ethoxy or 3-methoxypropyl, R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl and amino-C1-C6 alkyl, preferably each independently hydrogen, methyl, ethyl, aminomethyl or aminoethyl. Examples include but are not limited to 3-aminopropylmethoxydiethoxysilane, 3-aminopropyltriethoxysilane, and aminoethylaminopropyldimethoxyethoxysilane.

[0019] According to the present disclosure, the structural formula of the organic compound III is wherein R1-R6 are each independently selected from methyl, ethyl, propyl or phenyl, provided that 1-4 of R1-R6 are phenyl.

[0020] A second aspect of the present invention provides a method for preparing a ZSM-5 molecular sieve, the method comprising:

[0021] (a) mixing a silicon source I, an optional aluminum source I, water, an organic matter I and an organic matter II to obtain a mixture A;

[0022] (b) treating the mixture A to obtain a mixture B having a morphology-guiding effect;

[0023] (c) mixing mixture B, silicon source II, aluminum source II, water, template, and organic matter III to obtain mixture C;

[0024] (d) After the mixture C is crystallized, liquid-solid separation, washing, and drying are performed to obtain the molecular sieve.

[0025] In some embodiments, preferably, step (a) has one or more of the following features:

[0026] - In step (a), the silicon source I is one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, and tetraphenyl silicate;

[0027] - In step (a), the aluminum source I is one or more of aluminum sulfate, aluminum isopropoxide, sodium metaaluminate, and pseudo-boehmite;

[0028] - in step (a), the organic compound I is one or more of tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-butylamine, butylene diamine, hexamethyleneimine, and piperidine;

[0029] -The structural formula of organic compound II in step (a) is wherein R1-R3 are each independently selected from C1-C6 alkoxy and C1-C6 alkoxy-C1-C6 alkyl, preferably each independently methoxy, ethoxy or 3-methoxypropyl, R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl and amino-C1-C6 alkyl, preferably each independently hydrogen, methyl, ethyl, aminomethyl or aminoethyl;

[0030] -In step (a), the molar ratio of silicon source I, aluminum source I, water, organic matter I and organic matter II is silicon source I: aluminum source I: water: organic matter I: organic matter II = 1: (0-0.02): (5-20): (0.1-1): (0.05-0.3), wherein the silicon source I and the aluminum source I are calculated as SiO2 and Al2O3, respectively.

[0031] In some embodiments, preferably, the treatment in step (b) is carried out under closed conditions at 55-85° C. with stirring for 6-24 hours.

[0032] In some embodiments, preferably, step (c) has one or more of the following characteristics:

[0033] - In step (c), the silicon source II is one or more of silica sol, white carbon black, silicon powder, tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, and tetraphenyl silicate;

[0034] - In step (c), the aluminum source II is one or more of aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum isopropoxide, sodium metaaluminate, and pseudo-boehmite;

[0035] - In step (c), the template agent is one or more of tetrapropylammonium bromide, tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-propylamine, propylenediamine, n-butylamine, butylenediamine, n-hexylamine, hexamethylenediamine, aqueous ammonia, hexamethyleneimine, piperidine, and piperazine;

[0036] -The structural formula of the organic compound III in step (c) is wherein R1-R6 are each independently selected from methyl, ethyl, propyl and phenyl, provided that 1-4 of R1-R6 are phenyl;

[0037] -In step (c), the molar ratio of silicon source II, aluminum source II, water, template and organic matter III is, silicon source II: aluminum source II: water: template: organic matter III = 1: (0.0033-0.01): (8-20): (0.1-0.3): (0.01-0.10), and the ratio of the mass of the mixture B to the total mass of the five substances of silicon source II, aluminum source II, water, template and organic matter III is (0.05-0.2): 1, wherein the silicon source II and the aluminum source II are calculated as SiO2 and Al2O3, respectively.

[0038] In some embodiments, preferably, step (d) has one or more of the following characteristics:

[0039] - In step (d), the crystallization conditions are: crystallization at 110-170° C. for 12-72 hours under closed conditions;

[0040] In step (d), the liquid-solid separation method is filter paper filtration, centrifugation, or plate and frame filter press. The solid obtained by liquid-solid separation is washed multiple times with deionized water until the pH value of the washing liquid reaches 7-8. The drying condition is drying at 100-200°C for 5-12 hours.

[0041] Without being bound by any theory, it is believed that in the method of the present invention, the use of organic compound II allows mixture A to give small-sized nanoscale crystals modified with organic groups, and the use of organic compound III allows mixture C to give phenyl-modified plate-like crystals with a relatively short b-axis size and a relatively long c-axis size.

[0042] The third aspect of the present invention provides a catalyst for the alkylation of benzene to ethylbenzene, wherein the catalyst comprises a ZSM-5 molecular sieve, wherein the synthesized state of the ZSM-5 molecular sieve is the molecular sieve provided in the first aspect or the molecular sieve prepared by the method of the second aspect.

[0043] In some embodiments, in the catalyst, the ZSM-5 molecular sieve is in a calcined state.

[0044] In some embodiments, the catalyst optionally includes a binder, such as alumina, silica, or a mixture thereof, in addition to the ZSM-5 molecular sieve.

[0045] In some embodiments, preferably, in the catalyst, the content of molecular sieve is 80 mass% or more, preferably 80 mass%-90 mass%; the content of binder is 20 mass% or less, preferably 10%-20%, based on the total mass of the catalyst.

[0046] A fourth aspect of the present invention provides a method for preparing a catalyst for producing ethylbenzene by alkylation of benzene, comprising:

[0047] (e) mixing at least one of the molecular sieves described in the first aspect and the molecular sieve prepared in the second aspect, a binder and a polymer mixture, and then forming the mixture, followed by drying, calcination, ammonium exchange, steam treatment, and acid washing to obtain the catalyst.

[0048] In some embodiments, preferably, step (e) has one or more of the following characteristics:

[0049] - The binder is aluminum oxide, silicon oxide or a mixture thereof;

[0050] -The polymer mixture is a mixture of starch and a surfactant, wherein the mass ratio of starch to the polymer mixture is 55%-70%; the surfactant can be selected from, for example, a cationic surfactant and a non-ionic surfactant, such as at least one of octadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, P123 (manufactured by BASF, Germany), F127 (manufactured by BASF, Germany), polyethylene glycol ether or polyoxyethylene ethyl ether.

[0051] - The mass ratio of molecular sieve E, binder and polymer mixture is: molecular sieve E: binder: polymer mixture = 1: (0.1-0.4): (0.03-0.2);

[0052] At least one molding aid may be added in step (e), such as a peptizing acid (such as dilute nitric acid, for example, an aqueous solution of nitric acid with a mass concentration of 3%-10%), an extrusion aid (such as sesbania powder), etc.

[0053] In some embodiments, preferably, in step (e), the mass ratio of molecular sieve E, dilute nitric acid, and sesbania powder is: molecular sieve E: dilute nitric acid: sesbania powder = 1: (0.5-1.2): (0.01-0.05).

[0054] In some embodiments, preferably, the forming in step (e) is extrusion forming.

[0055] In some embodiments, preferably, the forming shape in step (e) is cylindrical, clover-shaped, four-leaf clover-shaped, gear-shaped, etc.

[0056] In some embodiments, the drying conditions are 100-200°C for 5-12 hours; the roasting conditions are 500-600°C for 4-10 hours; the ammonium exchange conditions are 2%-10% ammonium salt solution at 20-80°C for 1-10 hours, with 2-5 consecutive exchanges, and the ammonium salt is at least one of ammonium sulfate, ammonium chloride, ammonium acetate or ammonium nitrate; the steam treatment conditions are 300-450°C for 4-10 hours in a saturated steam atmosphere; the pickling conditions are 0.1%-3.0% acid solution at 20-80°C for 1-10 hours, and the acid is at least one of hydrochloric acid, sulfuric acid, nitric acid or oxalic acid.

[0057] The fifth aspect of the present invention provides a catalyst for producing ethylbenzene by alkylation of benzene prepared by the method of the fourth aspect.

[0058] In some embodiments, preferably, in the catalyst, based on the mass of the catalyst, the content of molecular sieve is more than 80%, preferably 80%-90%, and the content of binder is less than 20%, preferably 10%-20%.

[0059] A sixth aspect of the present invention provides a method for producing ethylbenzene by alkylation of benzene, wherein the reaction raw materials benzene and ethylene are contacted with the above-mentioned catalyst to generate a reaction effluent containing ethylbenzene.

[0060] In some embodiments, preferably, the mass concentration of ethylene in the ethylene feedstock is 10%-100%.

[0061] In some embodiments, preferably, the reaction temperature is 320-380°C, the reaction pressure is 0.5-2.6 MPa, and the ethylene mass space velocity is 0.2-2.5 h -1 , the molar ratio of benzene to ethylene is 4.0-7.0.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. The inventors of the present invention have found through research that the morphology, axial dimensions and ratios of ZSM-5 molecular sieves, as well as the area and ratios of crystal faces, of benzene alkylation catalysts have an important influence on their performance. Since the ZSM-5 molecular sieve crystal growth process follows the Ostwald-ripening and Wulff Construction rules, the ZSM-5 molecular sieves prepared by conventional methods are mostly coffin morphologies, and the special flaky morphology, specific axial dimensions and ratios, and specific crystal face areas and ratios are difficult to control. The inventors have found through further research that, during the molecular sieve preparation process, the introduction of organic matter II and organic matter III at different times can effectively control the flaky morphology of the molecular sieve, and the axial dimensions and ratios are within a specific range, while the areas and ratios of the three crystal faces (100), (010), and (101) are also within a specific range. When the ZSM-5 molecular sieve of the present invention is used in the benzene alkylation reaction to produce ethylbenzene, it can significantly improve the ethylene conversion rate, inhibit side reactions, reduce the content of the key impurity xylene, and extend the service life of the catalyst.

[0064] 2. The ZSM-5 molecular sieve of the present invention contains phenyl groups, and its infrared spectrum has a wave number range of 690-750cm -1 Two peaks appear within the molecular sieve. It is believed that the molecular sieve of the present invention can effectively inhibit the condensation of the binder with the silanol groups on the molecular sieve surface during the molding process, reduce the pore-blocking effect of the binder, and help improve the overall performance of the catalyst. In addition, after molding and calcination, the molecular sieve surface reserves spaces equivalent to the size of phenyl groups, which is conducive to the enrichment of benzene and increases the local benzene-olefin ratio, thereby helping to reduce the total feed benzene-olefin ratio and saving energy and reducing consumption during the reaction process.

[0065] 3. During the preparation process, the catalyst of the present invention not only uses a specific molecular sieve, but also adds a polymer mixture during the molding process, thereby reducing the blockage of the molecular sieve pores by the binder. The resulting catalyst has a high pore volume, suitable mechanical strength and suitable bulk density, and further improves the diffusion performance of the reaction molecules during the reaction process, which is beneficial to increasing the ethylene conversion rate, inhibiting side reactions, reducing the xylene content, and extending the life of the catalyst. It is particularly suitable for the gas-phase alkylation of industrial benzene and ethylene to produce ethylbenzene, and is applicable to a variety of ethylene raw materials, such as pure ethylene, dilute ethylene or ethanol.

[0066] 4. Because the alkylation of benzene and ethylene is a highly exothermic reaction, it significantly increases the temperature rise in the alkylation reactor, increasing the likelihood of side reactions and the rate of coking. This significantly increases the content of the key impurity xylene in the ethylbenzene product, significantly shortening the catalyst's service life. The catalyst of the present invention is particularly suitable for the vapor-phase alkylation of benzene and ethylene to produce ethylbenzene. Under reaction conditions with a low molar ratio of benzene to ethylene, the ethylene conversion is close to 100%, the ethyl selectivity in the alkylated product is greater than 99.6%, and the xylene content, a key impurity, is less than 600 ppm by mass.

[0067] 5. The method of the present invention can use any ethylene raw material, effectively expanding the source of ethylene raw materials, alleviating the tension of ethylene raw materials, and creating more economic benefits.

[0068] BRIEF DESCRIPTION OF THE DRAWINGS

[0069] FIG1 is an XRD spectrum of the molecular sieve prepared in Example 1 of the present invention;

[0070] FIG2 is a SEM photograph of the molecular sieve prepared in Example 1 of the present invention;

[0071] FIG3 is an infrared spectrum of the molecular sieve prepared in Example 1 of the present invention;

[0072] FIG4 is an XRD spectrum of the molecular sieve prepared in Comparative Example 1 of the present invention;

[0073] FIG5 is a SEM photograph of the molecular sieve prepared in Comparative Example 1 of the present invention. Example

[0074] The present invention will be described in detail below with reference to specific embodiments, but it should be understood that the protection scope of the present invention is not limited by these specific embodiments.

[0075] In the following examples and comparative examples, SEM images of the molecular sieves were obtained using a Hitachi S-4800 cold field emission high-resolution scanning electron microscope. The axial dimensions and crystal prism dimensions of the molecular sieves were obtained by statistically analyzing data from at least 300 grains in the SEM images. The axial distribution and crystal face names of the ZSM-5 molecular sieve are shown in the figure, where the area of ​​the (100) crystal face is S1 = Lb × Le, the area of ​​the (010) crystal face is S2 = La × Le + La × (Lc - Le) / 2, the area of ​​the (101) crystal face is S3 = Lb × Ld, and the exposure of the (010) crystal face is S2 / (S1 + S2 + 2S3) × 100%.

[0076] In the following examples and comparative examples, the XRD patterns of the molecular sieves were obtained using an Ultima IV X-ray powder diffractometer from Rigaku, Japan. The voltage was 35 kV, the current was 30 mA, and the scanning speed was 1°·min.-1 .

[0077] In the following examples and comparative examples, the SiO2 / Al2O3 molar ratio of the molecular sieve was tested using a Model S-35 ICP-AES analyzer from Kontron, Germany. Before the test, 50 mg of the sample was completely dissolved in 50 g of hydrofluoric acid solution.

[0078] In the following examples and comparative examples, infrared spectra of molecular sieves were obtained using an iS50 infrared spectrometer from Thermo Scientific, USA, using potassium bromide pellets, and the wave number test range was 400-4000 cm -1 .

[0079] [Example 1]

[0080] This example is used to illustrate the synthesis of ZSM-5 molecular sieve and the preparation of a catalyst for the alkylation of benzene to ethylbenzene.

[0081] (1) 208.3 g of tetraethyl silicate, 3.33 g of aluminum sulfate 18-hydrate, 180 g of water, 101.68 g of tetrapropylammonium hydroxide and 19.13 g of the structural formula (wherein R1 is a methoxy group, R2 and R3 are ethoxy groups, and R4 and R5 are hydrogen atoms) and an organic substance II are uniformly mixed to obtain a mixture A1, wherein tetraethyl silicate is calculated as SiO2: aluminum sulfate 18hydrate is calculated as Al2O3: water: tetrapropylammonium hydroxide: organic substance II = 1:0.005:10:0.5:0.1 (molar ratio).

[0082] (2) Mixture A1 was stirred in a sealed container at 75°C for 18 h to obtain mixture B1.

[0083] (3) 26.6 g of mixture B1, 60 g of silicon powder, 3.33 g of aluminum sulfate 18hydrate, 180 g of water, 9.02 g of ethylamine and 14.25 g of the structural formula (wherein R1 and R4 are phenyl groups, and R2, R3, R5 and R6 are methyl groups) are contacted with an organic matter III to obtain a mixture C1, wherein silicon powder is calculated as SiO2: aluminum sulfate 18hydrate is calculated as Al2O3: water: ethylamine: organic matter III = 1:0.005:10:0.2:0.05 (molar ratio).

[0084] (4) C1 was crystallized in a sealed container at 150°C for 48 hours to obtain a mixture D1, which was then centrifuged to obtain a solid. The solid was washed with deionized water several times until the pH of the washing solution reached 7.5, and then the washed solid was dried at 150°C for 10 hours to obtain molecular sieve E1.

[0085] (5) 50 g of E1, 15 g of alumina monohydrate, 30 g of a 5% nitric acid aqueous solution, 1.5 g of sesbania powder and 5 g of a polymer mixture (including 3 g of starch and 2 g of hexadecyltrimethylammonium bromide) were mixed and extruded into a cylindrical shape, and then treated at 150° C. for 8 hours; 550° C. for 6 hours; treated with a 5% ammonium sulfate solution at 50° C. for 6 hours, and exchanged 4 times continuously; treated at 400° C. in a saturated water vapor atmosphere for 6 hours; and treated with a 0.5% hydrochloric acid solution at 40° C. for 5 hours to obtain catalyst F1.

[0086] The XRD spectrum of molecular sieve E1 is shown in FIG1 , which has typical diffraction peaks of ZSM-5 molecular sieve.

[0087] The SEM photograph of molecular sieve E1 is shown in Figure 2. There are no twins in the molecular sieve. According to statistics, the size of the molecular sieve in the a-axis direction is La=293nm, the size in the b-axis direction is Lb=84nm, and the size in the c-axis direction is Lc=1970nm; the size of the crystal edge formed by the intersection of (010) and (101) crystal planes is Ld=190nm, and the size of the crystal edge formed by the intersection of (010) and (100) crystal planes is Le=1728nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=3.5, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=23.5.

[0088] The area of ​​the molecular sieve (100) crystal surface S1 = 145152nm 2 , the area of ​​(010) crystal plane S2=541757nm 2 , the area of ​​the (101) crystal plane S3=15960nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.27, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.029, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=75.4%.

[0089] The infrared spectrum of molecular sieve E1 is shown in Figure 4. -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 739cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 450cm -1 and 550cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E1 is 200.

[0090] [Example 2]

[0091] 152.2 g of tetramethyl silicate, 2.66 g of aluminum sulfate 18-hydrate, 360 g of water, 73.1 g of n-butylamine and 70.8 g of the structural formula (wherein R1 and R2 are methoxy groups, R3 is ethoxy group, R4 is 2-aminoethyl group, and R5 is hydrogen atom) and organic matter II are uniformly mixed to obtain mixture A2, wherein tetramethyl silicate is calculated as SiO2: aluminum sulfate 18hydrate is calculated as Al2O3: water: n-butylamine: organic matter II = 1:0.004:20:1:0.3 (molar ratio). Mixture A2 is stirred at 85°C for 8 hours in a sealed container to obtain mixture B2. 101 g of mixture B2, 60 g of white carbon black, 0.408 g of pseudo-boehmite, 360 g of water, 61 g of tetrapropylammonium hydroxide and 38.9 g of the structural formula (wherein R1-R3 are phenyl groups and R4-R6 are ethyl groups) and an organic compound III are contacted to obtain a mixture C2, wherein the molar ratio of silica (calculated as SiO2): pseudo-boehmite (calculated as Al2O3): water: tetrapropylammonium hydroxide: organic compound III is 1:0.004:20:0.3:0.1. C2 is crystallized in a sealed container at 170°C for 12 hours to obtain a mixture D2, which is then centrifuged to obtain a solid. The solid is washed with deionized water multiple times until the pH of the washing solution reaches 7.5, and then the washed solid is dried at 200°C for 5 hours to obtain molecular sieve E2.

[0092] 50 g of E2, 20 g of alumina monohydrate, 60 g of a 3% aqueous nitric acid solution, 2.5 g of sesbania powder and 10 g of a polymer mixture (including 7 g of starch and 3 g of P123) were mixed and extruded into a four-leaf clover shape. The catalyst F2 was then treated at 200°C for 5 hours; 600°C for 4 hours; treated with a 10% ammonium chloride solution at 80°C for 1 hour, with four consecutive exchanges; treated at 450°C in a saturated water vapor atmosphere for 4 hours; and treated with a 3% hydrochloric acid solution at 80°C for 1 hour to obtain the catalyst F2.

[0093] The molecular sieve E2 has typical ZSM-5 molecular sieve diffraction peaks as characterized by XRD.

[0094] SEM photos show that there are no twins in the molecular sieve E2. According to statistics, the size of the molecular sieve in the a-axis direction is La=270nm, the size in the b-axis direction is Lb=60nm, and the size in the c-axis direction is Lc=1560nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=180nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=1322nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=4.5, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=26.0.

[0095] The area of ​​the molecular sieve (100) crystal surface S1 = 79320 nm 2 , the area of ​​(010) crystal plane S2=389070nm 2 , the area of ​​the (101) crystal plane S3 = 10800nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.20, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.028, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=79.4%.

[0096] The infrared spectrum of molecular sieve E2 is at 690-750 cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 740cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 450cm -1 and 550cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E2 is 250.

[0097] [Example 3]

[0098] 208.3 g of tetraethyl silicate, 2.20 g of aluminum sulfate 18-hydrate, 90 g of water, 20.34 g of tetrapropylammonium hydroxide and 16.05 g of the structural formula (wherein R1 is methoxy, R2 is ethoxy, R3 is 3-methoxypropyl, R4 and R5 are methyl) and organic matter II are uniformly mixed to obtain mixture A3, wherein tetraethyl silicate is calculated as SiO2: aluminum sulfate 18hydrate is calculated as Al2O3: water: tetrapropylammonium hydroxide: organic matter II = 1:0.0033:5:0.1:0.05 (molar ratio). Mixture A3 is stirred at 55°C for 24 hours in a sealed container to obtain mixture B3. 18.23 g of mixture B3, 208.3 g of tetraethyl silicate, 2.20 g of aluminum sulfate 18hydrate, 144 g of water, 7.34 g of n-butylamine and 4.09 g of the structural formula (wherein R1, R2, R4, and R5 are phenyl groups, and R3 and R6 are methyl groups) and an organic compound III are contacted to obtain a mixture C3, wherein the molar ratio of tetraethyl silicate calculated as SiO2: aluminum sulfate 18hydrate calculated as Al2O3: water: n-butylamine: organic compound III is 1:0.0033:8:0.1:0.01. C3 is crystallized in a sealed container at 110°C for 72 hours to obtain a mixture D3, which is then centrifuged to obtain a solid. The solid is washed with deionized water multiple times until the pH of the washing solution reaches 7.5, and then the washed solid is dried at 100°C for 12 hours to obtain molecular sieve E3.

[0099] 50 g of E3, 5 g of alumina monohydrate, 25 g of a 3% aqueous nitric acid solution, 0.5 g of sesbania powder and 1.5 g of a polymer mixture (including 0.825 g of starch and 0.675 g of F127) were mixed and extruded into a four-leaf clover shape. The catalyst F3 was then treated at 100° C. for 12 hours; 500° C. for 10 hours; treated with a 2% ammonium acetate solution at 20° C. for 10 hours, with four consecutive exchanges; treated at 300° C. in a saturated water vapor atmosphere for 10 hours; and treated with a 0.1% oxalic acid solution at 20° C. for 10 hours to obtain the catalyst F3.

[0100] The molecular sieve E3 has typical ZSM-5 molecular sieve diffraction peaks as characterized by XRD.

[0101] SEM photos show that there are no twins in the molecular sieve E3. According to statistics, the size of the molecular sieve in the a-axis direction is La=240nm, the size in the b-axis direction is Lb=90nm, and the size in the c-axis direction is Lc=2200nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=220nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=1831nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=2.7, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=24.4.

[0102] The area of ​​the molecular sieve (100) crystal surface S1 = 164790 nm 2 , the area of ​​(010) crystal plane S2=483720nm 2 , the area of ​​the (101) crystal plane S3 = 19800nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.34, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.041, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=70.3%.

[0103] The infrared spectrum of molecular sieve E3 is at 690-750cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 739cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 449cm -1 and 550cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E3 is 298.

[0104] [Example 4]

[0105] 208.3 g of tetraethyl silicate, 180 g of water, 101.68 g of tetrapropylammonium hydroxide and 19.13 g of the structural formula (wherein R1 is a methoxy group, R2 and R3 are ethoxy groups, and R4 and R5 are hydrogen atoms) and organic matter II are uniformly mixed to obtain mixture A4, wherein tetraethyl silicate is calculated as SiO2: water: tetrapropylammonium hydroxide: organic matter II = 1:10:0.5:0.1 (molar ratio). Mixture A4 is stirred at 80°C for 10 hours in a sealed container to obtain mixture B4. 26.6 g of mixture B4, 60 g of silicon powder, 3.33 g of aluminum sulfate 18hydrate, 180 g of water, 9.02 g of ethylamine and 14.25 g of the structural formula (wherein R1 and R4 are phenyl groups, and R2, R3, R5, and R6 are methyl groups) and an organic compound III are contacted to obtain a mixture C4, wherein the molar ratio of silicon powder (calculated as SiO2): aluminum sulfate 18hydrate (calculated as Al2O3): water: ethylamine: organic compound III is 1:0.005:10:0.2:0.05. C4 is crystallized in a sealed container at 150°C for 48 hours to obtain a mixture D4, which is then centrifuged to obtain a solid. The solid is washed with deionized water multiple times until the pH of the washing solution reaches 7.5, and then the washed solid is dried at 150°C for 10 hours to obtain molecular sieve E4.

[0106] 50 g of E4, 15 g of alumina monohydrate, 30 g of a 5% aqueous nitric acid solution, 1.5 g of sesbania powder, and 5 g of a polymer mixture (including 3 g of starch and 2 g of cetyltrimethylammonium bromide) were mixed and extruded into a cylindrical shape. The catalyst F4 was then treated at 150° C. for 8 hours; 550° C. for 6 hours; treated with a 5% ammonium sulfate solution at 50° C. for 6 hours, with four consecutive exchanges; treated at 400° C. in a saturated water vapor atmosphere for 6 hours; and treated with a 0.5% hydrochloric acid solution at 40° C. for 5 hours to obtain the catalyst F4.

[0107] The molecular sieve E4 has typical ZSM-5 molecular sieve diffraction peaks as characterized by XRD.

[0108] SEM photos show that there are no twins in the molecular sieve E4. According to statistics, the size of the molecular sieve in the a-axis direction is La=245nm, the size in the b-axis direction is Lb=80nm, and the size in the c-axis direction is Lc=2000nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=215nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=1646nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=3.1, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=25.0.

[0109] The area of ​​the molecular sieve (100) crystal surface S1 = 131680 nm 2 , the area of ​​(010) crystal plane S2=446635nm 2 , the area of ​​the (101) crystal plane S3 = 17200nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.29, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.039, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=72.9%.

[0110] The infrared spectrum of molecular sieve E4 is at 690-750 cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 740cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 450cm -1 and 549cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E4 is 202.

[0111] [Comparative Example 1]

[0112] Compared with Example 1, the only difference is that: no structural formula is added (wherein R1 is a methoxy group, R2 and R3 are ethoxy groups, and R4 and R5 are hydrogen atoms) to obtain the organic compound II, molecular sieve E5 and further catalyst F5.

[0113] The XRD spectrum of molecular sieve E5 is shown in FIG5 , which has typical diffraction peaks of ZSM-5 molecular sieve.

[0114] The SEM photograph of molecular sieve E5 is shown in Figure 6. There is no twin. According to statistics, the size of the molecular sieve in the a-axis direction is La = 238nm, the size in the b-axis direction is Lb = 160nm, and the size in the c-axis direction is Lc = 286nm; the size of the crystal edge formed by the intersection of (010) and (101) crystal planes is Ld = 152nm, and the size of the crystal edge formed by the intersection of (010) and (100) crystal planes is Le = 97nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb = 1.5, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb = 1.8.

[0115] The area of ​​the molecular sieve (100) crystal surface S1 = 15520 nm 2 , the area of ​​(010) crystal plane S2=45577nm 2 , the area of ​​the (101) crystal plane S3 = 24320nm 2; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.34, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.534, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=41.5%.

[0116] The infrared spectrum of molecular sieve E5 is at 690-750cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 740cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 450cm -1 and 550cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E5 is 202.

[0117] [Comparative Example 2]

[0118] Compared with Example 1, the only difference is that: no structural formula is added (wherein R1 and R4 are phenyl groups, and R2, R3, R5 and R6 are methyl groups) to obtain the organic compound III, molecular sieve E6 and further catalyst F6.

[0119] The XRD characterization showed that the molecular sieve E6 had typical diffraction peaks of ZSM-5 molecular sieve.

[0120] SEM photos show that there are no twins in the molecular sieve E6. According to statistics, the size of the molecular sieve in the a-axis direction is La=360nm, the size in the b-axis direction is Lb=185nm, and the size in the c-axis direction is Lc=2100nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=228nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=1820nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=1.9, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=11.4.

[0121] The area of ​​the molecular sieve (100) crystal surface S1 = 336700nm 2 , the area of ​​(010) crystal plane S2=705600nm 2 , the area of ​​the (101) crystal plane S3=42180nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.48, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.060, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=62.6%.

[0122] The infrared spectrum of molecular sieve E6 is not in the range of 690-750 cm -1 There are two peaks in the zeolite. The SiO2 / Al2O3 molar ratio of molecular sieve E6 is 201.

[0123] [Comparative Example 3]

[0124] Compared with Example 1, the only difference is that 0.995 g of organic matter II and 14.25 g of organic matter III are added simultaneously in step (3) to obtain molecular sieve E7 and further obtain catalyst F7.

[0125] The molecular sieve E7 has typical ZSM-5 molecular sieve diffraction peaks as characterized by XRD.

[0126] SEM photos show that there are no twins in the molecular sieve E7. According to statistics, the size of the molecular sieve in the a-axis direction is La=234nm, the size in the b-axis direction is Lb=155nm, and the size in the c-axis direction is Lc=368nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=185nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=82nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=1.5, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=2.4.

[0127] The area of ​​the molecular sieve (100) crystal surface S1 = 12710 nm 2 , the area of ​​(010) crystal plane S2=52650nm 2 , the area of ​​the (101) crystal plane S3=28675nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.24, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.545, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=42.9%.

[0128] The infrared spectrum of molecular sieve E7 is at 690-750 cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 740cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 449cm -1 and 549cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E7 is 202.

[0129] [Comparative Example 4]

[0130] Compared with Example 1, the only difference is that in step (3), an equimolar amount (9.57 g) of the structural formula is used. (wherein R1 is a methoxy group, R2 and R3 are ethoxy groups, and R4 and R5 are hydrogen atoms) the alternative structural formula of the organic compound II is (wherein R1 and R4 are phenyl groups, and R2, R3, R5 and R6 are methyl groups) to obtain the organic compound III, molecular sieve E8 and further catalyst F8.

[0131] The XRD characterization showed that the molecular sieve E8 had typical diffraction peaks of ZSM-5 molecular sieve.

[0132] SEM photos show that there are no twins in the molecular sieve E8. According to statistics, the size of the molecular sieve in the a-axis direction is La=325nm, the size in the b-axis direction is Lb=130nm, and the size in the c-axis direction is Lc=2052nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=255nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=1658nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=2.5, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=15.8.

[0133] The area of ​​the molecular sieve (100) crystal surface S1 = 215540 nm 2 , the area of ​​(010) crystal plane S2=602875nm 2 , the area of ​​the (101) crystal plane S3=33150nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.36, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.055, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=68.1%.

[0134] The infrared spectrum of molecular sieve E8 is not in the range of 690-750cm -1 There are two peaks in the zeolite. The SiO2 / Al2O3 molar ratio of molecular sieve E6 is 201.

[0135] [Comparative Example 5]

[0136] Compared with Example 1, the only difference is that in step (1), an equimolar (28.5 g) structural formula is used. (wherein R1 and R4 are phenyl groups, and R2, R3, R5, and R6 are methyl groups) the alternative structural formula of the organic compound III is (wherein R1 is a methoxy group, R2 and R3 are ethoxy groups, and R4 and R5 are hydrogen atoms) to obtain the organic compound II, molecular sieve E9 and further catalyst F9.

[0137] The molecular sieve E9 has typical ZSM-5 molecular sieve diffraction peaks as characterized by XRD.

[0138] SEM photos show that there are no twins in the molecular sieve E9. According to statistics, the size of the molecular sieve in the a-axis direction is La=216nm, the size in the b-axis direction is Lb=148nm, and the size in the c-axis direction is Lc=827nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=170nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=564nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=1.5, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=5.6.

[0139] The area of ​​the molecular sieve (100) crystal surface S1=83472nm 2 , the area of ​​(010) crystal plane S2=150228nm 2 , the area of ​​the (101) crystal plane S3=25160nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.56, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.167, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=52.9%.

[0140] The infrared spectrum of molecular sieve E9 is at 690-750 cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 740cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 449cm -1 and 549cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E9 is 201.

[0141] [Comparative Example 6]

[0142] Compared with Example 1, the only difference is that in step (2), the mixture A is stirred in a closed container at 90° C. for 18 h to obtain molecular sieve E10 and further obtain catalyst F10.

[0143] The XRD characterization showed that the molecular sieve E10 had typical diffraction peaks of ZSM-5 molecular sieve.

[0144] SEM photos show that there are no twins in the molecular sieve E10. According to statistics, the size of the molecular sieve in the a-axis direction is La=305nm, the size in the b-axis direction is Lb=92nm, and the size in the c-axis direction is Lc=1450nm; the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=261nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=1026nm; the size ratio of the a-axis direction to the b-axis direction is La / Lb=3.3, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=15.8.

[0145] The area of ​​the molecular sieve (100) crystal surface S1 = 94392 nm 2 , the area of ​​(010) crystal plane S2=377590nm 2 , the area of ​​the (101) crystal plane S3=24012nm 2 ; The area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.25, the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.064, and the exposure of the (010) crystal plane is S2 / (S1+S2+2S3)×100%=72.6%.

[0146] The infrared spectrum of molecular sieve E10 is at 690-750 cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 700 cm -1 and 739cm -1 ; In the wave number range 440-560cm -1 There are two peaks, and the wave numbers corresponding to the peak apex are 450cm -1 and 550cm -1 The SiO2 / Al2O3 molar ratio of molecular sieve E10 is 201.

[0147] [Examples 5-8]

[0148] Catalysts F1-F4 prepared in Examples 1-4 were respectively applied to the alkylation of benzene to ethylbenzene, wherein the ethylene mass concentration was 50%, the reaction temperature was 340°C, the pressure was 2.2 MPa, and the ethylene mass space velocity was 0.8 h -1 Under the condition of a benzene to ethylene molar ratio of 4.0, the ethylene conversion, ethyl selectivity in the alkylation product, and the content of the key impurity xylene were tested. The test results are shown in Table 1 below.

[0149] [Comparative Examples 6-10]

[0150] Catalysts F5-F10 prepared in Comparative Examples 1-6 were respectively applied to the alkylation of benzene to ethylbenzene, wherein the ethylene mass concentration was 50%, the reaction temperature was 340°C, the pressure was 2.2 MPa, and the ethylene mass space velocity was 0.8 h-1 Under the condition of a benzene to ethylene molar ratio of 4.0, the ethylene conversion, ethyl selectivity in the alkylation product, and the content of the key impurity xylene were tested. The test results are shown in Table 1 below.

[0151] Table 1 Benzene alkylation reaction results for ethylbenzene

[0152] [Examples 9-12]

[0153] The catalysts F1-F4 prepared in Examples 1-4 were tested for their deactivation time in the benzene alkylation reaction to ethylbenzene under harsh reaction conditions, wherein the ethylene mass concentration was 50%, the reaction temperature was 400°C, the pressure was 2.2 MPa, and the ethylene mass space velocity was 20 h -1 The test was conducted under the condition that the molar ratio of benzene to ethylene was 2.0. The deactivation time refers to the time from the start of the reaction to the time when the ethylene conversion rate dropped to 40% of the initial conversion rate. The test results are shown in Table 2 below.

[0154] [Comparative Examples 11-15]

[0155] The catalysts F5-F10 prepared in Comparative Examples 1-5 were tested for their deactivation time in the benzene alkylation to ethylbenzene reaction under harsh reaction conditions, wherein the ethylene mass concentration was 50%, the reaction temperature was 400°C, the pressure was 2.2 MPa, and the ethylene mass space velocity was 20 h -1 The deactivation time is the time from the start of the reaction to the time when the ethylene conversion rate drops to 40% of the initial conversion rate. The test results are shown in Table 2 below. Under the ultra-high ethylene space velocity reaction conditions, the deactivation time of catalysts F1-F4 is significantly longer than that of catalysts F5-F10.

[0156] Table 2 Test results of catalyst deactivation time under ultra-high space velocity reaction conditions

[0157] The above describes in detail the specific embodiments of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as the contents disclosed by the present invention and fall within the scope of protection of the present invention.

Claims

1. A ZSM-5 molecular sieve, characterized in that: The molecular sieve has no twins, and the size in the a-axis direction is La=240-300nm, the size in the b-axis direction is Lb=60-90nm, and the size in the c-axis direction is Lc=1500-2200nm; In the molecular sieve, the size of the crystal edge formed by the intersection of the (010) and (101) crystal planes is Ld=180-220nm, and the size of the crystal edge formed by the intersection of the (010) and (100) crystal planes is Le=1300-1900nm; And, in the molecular sieve, the size ratio of the a-axis direction to the b-axis direction is La / Lb=2.5-4.5, and the size ratio of the c-axis direction to the b-axis direction is Lc / Lb=22.0-26.

0.

2. The molecular sieve according to claim 1, characterized in that In the molecular sieve, the area of ​​the (100) crystal plane S1 = 75000-180000 nm 2 , (010) crystal plane area S2 = 350000-600000nm 2 , (101) crystal plane area S3 = 10000-20000nm 2 ; In the molecular sieve, the area ratio of the (100) crystal plane to the (010) crystal plane is S1 / S2=0.20-0.35, and the area ratio of the (101) crystal plane to the (010) crystal plane is S3 / S2=0.025-0.045; And, in the molecular sieve, the exposure degree of (010) crystal plane is S2 / (S1+S2+2S3)×100%=70-80%.

3. The molecular sieve according to claim 1 or 2, characterized in that The infrared spectrum of the molecular sieve is in the wave number range of 690-750cm -1 There are two peaks P1 and P2 in the spectrum, and the wavenumber ranges corresponding to the peaks of P1 and P2 are 690-710 cm -1 and 730-750cm -1 ; The infrared spectrum of the molecular sieve is in the wave number range of 440-560 cm -1 There are two peaks P3 and P4 in the sample, and the wavenumber ranges corresponding to the peaks of P3 and P4 are 440-460 cm -1 and 540-560cm -1 ;and The SiO2 / Al2O3 molar ratio of the molecular sieve is 100-300.

4. The molecular sieve according to claim 1, characterized in that The chemical composition of the molecular sieve in the synthesized state includes: SiO2: nAl2O3: mE2: xE3, wherein E2 is organic matter II, E3 is organic matter III, n is 0.0033-0.01, m is 0.0015-0.005, x is 0.005-0.1, and the molecular sieve in the synthesized state optionally contains a template and water, wherein the molar ratio of the template to SiO2 is 0.05-0.3, and the molar ratio of water to SiO2 is 3-20, The structural formula of the organic substance II is wherein R1-R3 are each independently selected from C1-C6 alkoxy and C1-C6 alkoxy-C1-C6 alkyl, preferably each independently methoxy, ethoxy or 3-methoxypropyl, R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl and amino-C1-C6 alkyl, preferably each independently hydrogen, methyl, ethyl, aminomethyl or aminoethyl, The structural formula of the organic compound III is wherein R1-R6 are each independently selected from methyl, ethyl, propyl or phenyl, provided that 1 to 4 of R1-R6 are phenyl.

5. A method for preparing the ZSM-5 molecular sieve according to any one of claims 1 to 4, the method comprising: (a) mixing a silicon source I, an optional aluminum source I, water, an organic matter I and an organic matter II to obtain a mixture A; (b) treating the mixture A to obtain a mixture B having a morphology-guiding effect; (c) mixing mixture B, silicon source II, aluminum source II, water, template and organic matter III to obtain mixture C; (d) crystallizing the mixture C, and then subjecting it to liquid-solid separation, washing, and drying to obtain the molecular sieve; The organic compound I is one or more of tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-butylamine, dibutylamine, hexamethyleneimine, and piperidine; The structural formula of organic compound II is wherein R1-R3 are each independently selected from C1-C6 alkoxy and C1-C6 alkoxy-C1-C6 alkyl, preferably each independently methoxy, ethoxy or 3-methoxypropyl, R4 and R5 are each independently selected from hydrogen, C1-C6 alkyl and amino-C1-C6 alkyl, preferably each independently hydrogen, methyl, ethyl, aminomethyl or aminoethyl; The structural formula of organic compound III is Wherein R1-R6 are each independently selected from methyl, ethyl, propyl or phenyl, and 1 to 4 of R1-R6 are phenyl.

6. The preparation method according to claim 4, characterized in that: In step (a), the silicon source I is one or more of tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, and tetraphenyl silicate; and / or, in step (a), the aluminum source I is one or more of aluminum sulfate, aluminum isopropoxide, sodium aluminate, and pseudo-boehmite; Preferably, in step (a), the molar ratio of silicon source I, aluminum source I, water, organic matter I and organic matter II is silicon source I: aluminum source I: water: organic matter I: organic matter II = 1: (0-0.02): (5-20): (0.1-1.0): (0.05-0.3), wherein silicon source I and aluminum source I are calculated as SiO2 and Al2O3, respectively.

7. The preparation method according to claim 4, characterized in that: The treatment in step (b) is carried out under closed conditions at 55-85° C. with stirring for 6-24 hours; and / or the crystallization conditions in step (d) are carried out under closed conditions at 110-170° C. for 12-72 hours.

8. The preparation method according to claim 4, characterized in that In step (c), the silicon source II is one or more of silica sol, white carbon black, silicon powder, tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, and tetraphenyl silicate; and / or, the aluminum source II in step (c) is one or more of aluminum nitrate, aluminum chloride, aluminum sulfate, aluminum isopropoxide, sodium aluminate, and pseudo-boehmite; and / or, the template in step (c) is one or more of tetrapropylammonium bromide, tetrapropylammonium hydroxide, ethylamine, ethylenediamine, n-propylamine, propylenediamine, n-butylamine, butanediamine, n-hexylamine, hexamethylenediamine, ammonia water, hexamethyleneimine, piperidine, and piperazine; Preferably, in step (c), the molar ratio of silicon source II, aluminum source II, water, template and organic matter III is, silicon source II: aluminum source II: water: template: organic matter III = 1: (0.0033-0.010): (8-20): (0.1-0.3): (0.01-0.10), and the ratio of the mass of the mixture B to the total mass of the five substances of silicon source II, aluminum source II, water, template and organic matter III is (0.05-0.2): 1, wherein the silicon source II and the aluminum source II are calculated as SiO2 and Al2O3, respectively.

9. A catalyst for preparing ethylbenzene by alkylation of benzene, characterized in that: The catalyst comprises the molecular sieve according to any one of claims 1 to 4 or the molecular sieve prepared by the method according to any one of claims 5 to 9, and optionally comprises a binder such as alumina and / or silica.

10. A method for preparing a catalyst for preparing ethylbenzene by alkylation of benzene, comprising: (e) mixing the molecular sieve according to any one of claims 1 to 4, at least one of the molecular sieves prepared by the method according to any one of claims 5 to 9, a binder and a polymer mixture, and then forming the mixture, drying, calcining and ammonium exchanging. The catalyst is obtained by steam treatment and acid washing treatment.

11. The preparation method according to claim 10, characterized in that: In step (e), the binder is aluminum oxide and / or silicon oxide; and / or, in step (e), the polymer mixture is a mixture of starch and a surfactant, wherein the mass ratio of starch to the polymer mixture is 55%-70%; Preferably, in step (e), the mass ratio of molecular sieve E, binder and polymer mixture is: molecular sieve E: binder: polymer mixture = 1: (0.1-0.4): (0.03-0.2); Preferably, in step (e), the drying condition is 100-200°C for 5-12 hours; the roasting condition is 500-600°C for 4-10 hours; and the steam treatment condition is 300-450°C for 4-10 hours in a saturated steam atmosphere.

12. A method for preparing ethylbenzene by alkylation of benzene, characterized in that: The reaction raw materials benzene and ethylene are contacted with the catalyst according to claim 9 or the catalyst prepared by the method according to any one of claims 10 to 11 to form a reaction effluent containing ethylbenzene.

13. The method according to claim 12, characterized in that The ethylene mass concentration in the ethylene feedstock is 10%-100%; and / or, the reaction conditions are as follows: the reaction temperature is 320-380°C, the reaction pressure is 0.5-2.6MPa, and the ethylene mass space velocity is 0.2-2.5h -1 , the molar ratio of benzene to ethylene is 4.0-7.0.

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