A catalyst for the alkylation of benzene with methanol and a method for its preparation and use

Abstract

The application discloses a benzene and methanol alkylation catalyst and a preparation method and application thereof. The catalyst comprises graphene oxide-containing molecular sieves and metal oxides, and the morphology of the catalyst is a multi-stage pore column body. The preparation method of the catalyst comprises the following steps: (1) mixing a silicon source, an aluminum source, an organic template agent and water to prepare a mixed solution; (2) mixing a graphene oxide dispersion liquid with the mixed solution prepared in the step (1), and crystallizing to obtain graphene oxide-containing molecular sieves; and (3) loading a metal source on the graphene oxide-containing molecular sieves to obtain the catalyst. When the catalyst is used in a benzene and methanol alkylation reaction, the conversion rate of benzene can be effectively improved, the selectivity of toluene and xylene can be improved, and the selectivity of a byproduct ethylbenzene can be reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysis, and particularly relates to a catalyst for benzene and methanol alkylation and a preparation method thereof, and application of the catalyst in benzene and methanol alkylation. BACKGROUND

[0002] The benzene and methanol alkylation reaction for preparing toluene and xylene can effectively utilize the excess benzene and methanol resources, and can cope with the high market demand of toluene and xylene, and has high development value.

[0003] At present, there are few literatures on the benzene and methanol alkylation reaction for preparing toluene, and most of them are related literatures on preparing xylene. CN104226357A discloses improving the selectivity of xylene by adjusting the molecular sieve channel. CN102600887A discloses a catalyst prepared by loading alkaline earth and rare earth metal elements on a hydrogen type MCM-22 molecular sieve, and when the catalyst is used, the conversion rate of benzene and the selectivity of xylene are low. CN104492476A discloses a method for preparing toluene by modifying ZSM molecular sieve with alkaline metal, but the selectivity of toluene is low. CN102205251B discloses a phosphorus-modified IM-5 molecular sieve for toluene alkylation reaction, and the catalyst with the molecular sieve as an active component can minimize the side reactions in the toluene alkylation reaction, so that the selectivity of xylene reaches 100%, and the conversion rate of toluene is high. CN102464328A utilizes a mixing method to physically composite MCM-49 molecular sieve and beta molecular sieve for alkylation reaction of propylene and benzene, although the reaction result is good, but the physical compounding has little change on the pore structure and acidity of the catalyst. CN103121912A discloses a method for preparing xylene by methylation and transalkylation, mainly solves the problems that in the existing toluene disproportionation or toluene disproportionation and transalkylation technology, the xylene yield is mainly determined by the methylbenzene ring ratio in the raw material, and when the heavy aromatic hydrocarbon raw material is insufficient, the xylene production is low, and a large amount of benzene is produced. The method uses methanol and C12 or less aromatic hydrocarbon without or with a small amount of xylene as raw materials, under the conditions of a reaction temperature of 300-500 DEG C, a reaction pressure of normal pressure-10.0 MPa, and a raw material weight space velocity of 0.3-10 h-1, the raw materials are contacted with a solid acid catalyst, the alkylation reaction of methanol and aromatic hydrocarbon occurs on the catalyst, and the transalkylation of aromatic hydrocarbons occurs to obtain xylene products, which can be used in xylene industrial production. -1

[0004] ​In summary, there are still many problems in the process of preparing toluene and xylene by benzene alkylation with methanol: high content of by-product ethylbenzene, low utilization rate of methanol, low selectivity of xylene, and fast deactivation of catalyst, etc. Among them, the catalyst is the core of the alkylation reaction, and its own physicochemical properties play a decisive role in the conversion capacity and product selectivity. Therefore, providing a new catalyst for benzene alkylation with methanol is an important research topic. SUMMARY

[0005] In view of the low benzene conversion rate, low selectivity of toluene and xylene, and high content of by-product ethylbenzene in the preparation of toluene and xylene by benzene alkylation with methanol in the prior art, a new benzene alkylation catalyst with methanol, its preparation method and application are provided. The catalyst is used in toluene alkylation reaction, and has the characteristics of high benzene conversion rate, high selectivity of toluene and xylene, and low content of ethylbenzene.

[0006] The first aspect of the present application provides a benzene alkylation catalyst with methanol, which comprises a molecular sieve containing graphene oxide and a metal oxide, and the morphology of the catalyst is a multi-stage pore column body.

[0007] In the above technical solution, the molecular sieve is selected from at least one of ZSM-5 molecular sieve or ZSM-11 molecular sieve, preferably ZSM-5 molecular sieve.

[0008] In the above technical solution, the molar ratio of SiO2 / Al2O3 in the catalyst is 30-200, preferably 120-180.

[0009] In the above technical solution, the metal in the metal oxide is selected from at least one of lanthanum, cerium, cobalt, manganese, copper, vanadium, titanium, platinum or nickel, preferably at least one of lanthanum and cerium.

[0010] In the above technical solution, the thickness of graphene oxide in the molecular sieve containing graphene oxide is 0.4-1.0nm, preferably 0.5-0.8nm.

[0011] In the above technical solution, the mass content of graphene oxide in the molecular sieve containing graphene oxide is 0.01%-1.0%, preferably 0.1%-0.5%.

[0012] In the above technical solution, the mass content of the molecular sieve containing graphene oxide in the catalyst is 70%-99%, preferably 80%-95%, and the mass content of the metal oxide is 1%-30%, preferably 5%-20%, based on the weight of the catalyst.

[0013] In the above technical solution, the relative crystallinity of the catalyst is 85%-120%, the specific surface area is 400-1300m 2 / g, preferably 800-1300m2 / g. In the above technical solution, the catalyst has a hierarchical porous column morphology, and the thickness of the hierarchical porous column is 300-1100 nm. The thickness of the hierarchical porous column refers to its length along the b-axis orientation.

[0014] In the above technical solution, the catalyst simultaneously contains micropores, mesopores, and macropores. Mesopores refer to pores with a diameter of 2-50 nm, micropores refer to pores with a diameter less than 2 nm, and macropores refer to pores with a diameter greater than 50 nm. Further, the mesopores account for 30%-65% of the total pore volume, preferably 45%-61%, the micropores account for 30%-45% of the total pore volume, preferably 35%-45%, and the macropores account for 4%-15% of the total pore volume, preferably 4%-12%.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst, comprising:

[0016] (1) Prepare a mixture by mixing silicon source, aluminum source, organic template agent and water;

[0017] (2) Mix the graphene oxide dispersion with the mixture prepared in step (1), crystallize, and obtain a molecular sieve containing graphene oxide;

[0018] (3) The catalyst is prepared by loading a metal source onto a molecular sieve containing graphene oxide.

[0019] In the above technical solution, in step (1), the aluminum source is selected from one or more of sodium aluminate, boehmite, aluminum hydroxide, aluminum isopropoxide, aluminum nitride, aluminum sulfide, or aluminum powder; the silicon source is selected from one or more of tetraethyl orthosilicate, sodium silicate nonahydrate, silica sol, water glass, silica, fumed silica, or methyl orthosilicate; the organic base template agent is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide (TPAOH), or tetrabutylammonium hydroxide; and the water is preferably deionized water. The molar ratio of silicon source (SiO2), aluminum source (Al2O3), organic template agent, and water is 1:0.005-0.033:0.1-1.0:12-150.

[0020] In the above technical solution, in step (2), the amount of graphene oxide added is 0.01%-1.0% of the mass of silicon source in the mixture prepared in step (1) as SiO2, preferably 0.1%-0.5%.

[0021] In the above technical solution, in step (2), the preparation method of the graphene oxide dispersion liquid is as follows: graphene oxide is dispersed in water (preferably ultrapure water), and ultrasonic is performed to form a graphene oxide dispersion liquid. The amount of graphene oxide is 0.1-50 mg per 100 mL of aqueous solution, and the ultrasonic conditions are as follows: the frequency is 20-40 kHz, the power is 1000-2000 W, the ultrasonic time is 30 s-60 min, and preferably 10-30 min.

[0022] In the above technical solution, in step (2), the crystallization treatment conditions are as follows: the crystallization temperature is 120-220℃, preferably 120-180℃, and the crystallization time is 12-124 hours, preferably 6-48 hours.

[0023] In the above technical solution, in step (2), the crystallized material is separated, washed, dried and calcined to obtain the molecular sieve containing graphene oxide. The drying conditions are as follows: the drying temperature is 40-150℃, preferably 80-120℃, and the drying time is 3-124 hours, preferably 12-48 hours. The calcination conditions are as follows: the calcination temperature is 500-950℃, preferably 550-800℃, and the calcination time is 2-24h, preferably 4-10h.

[0024] In the above technical solution, in step (3), the metal source can be loaded by at least one of the conventional loading methods, such as impregnation or physical mixing followed by extrusion.

[0025] In the above technical solution, in step (3), according to the loading method, the metal source can be selected from the above-mentioned metal compounds or metal oxides, and the metal compounds include but are not limited to lanthanum nitrate, cerium nitrate, molybdenum oxide, and cobalt trioxide.

[0026] The third aspect of the present application provides the use of the above-mentioned catalyst in the preparation of toluene and xylene from benzene and methanol.

[0027] In the above technical solution, benzene and methanol are contacted with the above-mentioned catalyst for reaction, and the reaction conditions are as follows: the molar ratio of benzene to methanol is 0.1-10, the mass space velocity of the reaction raw material is 0.1-5.0 hours -1 , the reaction temperature is 350-500℃, and the reaction pressure is 0.1-1.0 MPa. The reaction raw material can be carried by a carrier gas when entering the catalyst bed, and the carrier gas can be an inert gas (such as nitrogen), and the molar ratio of the carrier gas to the mixed raw material is 5-20.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The catalyst of the present application is modified by using graphene oxide and specific metal to molecular sieve, so that the catalyst forms a columnar morphology, and the relative crystallinity of the molecular sieve remains basically unchanged. When used in the benzene and methanol alkylation reaction, the catalyst can effectively improve the conversion rate of benzene, and improve the selectivity of toluene and xylene, and reduce the selectivity of by-product ethylbenzene. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the XRD (X-ray diffraction) spectrum of the catalyst prepared in Example 1, Example 2, Example 8, Comparative Example 1 and Comparative Example 2 of the present application;

[0031] Figure 2 is the SEM (scanning electron microscope) graph of the catalyst prepared in Example 1 of the present application;

[0032] Figure 3 is the SEM (scanning electron microscope) graph of the catalyst prepared in Comparative Example 1 of the present application;

[0033] Figure 4 is the SEM (scanning electron microscope) graph of the catalyst prepared in Example 8 of the present application. DETAILED DESCRIPTION

[0034] The present application will be further described in conjunction with the examples, but the present application is not limited to the examples.

[0035] In the present application, the crystal structure of the sample is analyzed by using a Bruker D8 Advance X-ray diffractometer (XRD), the light source is a Cu Kα target, λ = 0.1542 nm, the tube voltage is 40 kV, and the tube current is 50 mA. The peak area of the molecular sieve obtained in Comparative Example 1 at 2θ = 9.3 ° The relative crystallinity of the treated sample is calculated by dividing the peak area of the other samples at this position by the peak area of Comparative Example 1 at this position.

[0036] In the present application, the crystal morphology is observed by Zeiss Merlin scanning electron microscope (SEM), the accelerating voltage of the SEM is 2 kV, the sample is uniformly dispersed on the sample stage with conductive glue, and the test is carried out.

[0037] In the present application, the reaction of benzene / methanol alkylation to prepare toluene and xylene is carried out in a normal pressure fixed bed reactor. The product is analyzed by Agilent 8890A gas chromatograph (GC). The gas chromatograph equipped with a flame ionization detection (FID) device and a HP-PONA capillary column (50 m x 0.2 mm x 0.5 μm) is used to analyze the product gas mixture regularly. The oven temperature is kept at 343 K.

[0038] In this invention, the specific surface area and pore structure of the catalyst were tested on a Micromeritics ASAP 2020M physical adsorption instrument. Before the test, the sample was degassed under vacuum at 350°C for 4 h, and the specific surface area of ​​the sample was calculated using the BET method. Example 1

[0039] Weigh 14.0 g of tetraethyl orthosilicate and 11.0 g of tetrapropylammonium hydroxide, dissolve them in 42 g of deionized water, stir until homogeneous, then add 0.20 g of aluminum isopropoxide and stir until homogeneous to form a transparent solution A-1. Add 15 mg of graphene oxide (0.5 nm thick) to A-1 and disperse it in 10 mL of ultrapure water to form a homogeneous mixture B-1, stir until homogeneous, and then sonicate it for 30 s in an ultrasonic machine at a frequency of 20 kHz and a power of 2000 W. This solution is recorded as solution C-1. Then, transfer the raw material to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene and place it in an oven for crystallization at 180 °C for 96 h. Wash and filter the obtained product, dry it at 100 °C for 12 h, and calcine it at 650 °C for 6 h to obtain product D-1.

[0040] Take 10g of product D-1, add 100ml of 0.1mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, filter and wash, and dry at 100℃ for 12 hours to obtain the final product E-1. The SiO2 / Al2O molar ratio in catalyst E-1 is 140.

[0041] The XRD pattern of product E-1 is shown below. Figure 1 It exhibits a typical ZSM-5 molecular sieve structure with a relative crystallinity of 90%. A scanning electron microscope image of product E-1 can be found here. Figure 2 ,Depend on Figure 2 The catalyst surface exhibits a hierarchical porous structure, with E-1 having a specific surface area of ​​1205 m². 2 / g. The mesopores account for 45% of the total pore volume, the micropores account for 43% of the total pore volume, and the macropores account for 12% of the total pore volume.

[0042] The above-mentioned product E-1 powder was compressed into tablets and sieved to obtain 20-40 mesh catalyst particles Cat1. Using a fixed-bed reactor, 5 g of shaped catalyst Cat1 was loaded. At room temperature, benzene and methanol were mixed in a molar ratio of 1:1, vaporized, and evenly dispersed before entering the reactor. The reaction was carried out at a reaction temperature of 500℃, atmospheric pressure, and a benzene-methanol mass hourly space velocity of 2.0 h⁻¹. -1 The reaction was carried out under certain conditions, and a gaseous product stream was obtained after the reaction. After cooling, the stream was passed into a gas-liquid separator for separation. The liquid product was sampled and analyzed. The test results are shown in Table 1. Example 2

[0043] Take 14.0 g of tetraethyl orthosilicate, 11.0 g of tetrapropylammonium hydroxide dissolved in 42 g of deionized water, stir evenly, then add 0.20 g of aluminum isopropoxide, stir evenly, form a transparent solution A-2. Add 15 mg of graphene oxide (thickness of 0.5 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-2, stir evenly, then ultrasonic in a ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-2, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 180℃ for 96 h. The obtained product is washed, suction filtered and dried at 100℃ for 12 h, then calcined at 650℃ for 6 h to obtain product D-2.

[0044] Take 10 g of product D-2, add 100 ml of 0.1 mol / L cerium nitrate solution, stir at 40℃ for 4 hours, suction filter and wash, then dry at 100℃ for 12 h to obtain the final product E-2. The molar ratio of SiO2 / Al2O in the catalyst E-2 is 140.

[0045] The XRD spectrum of product E-2 is shown in Figure 1 , which has a typical ZSM-5 molecular sieve structure, and the relative crystallinity is 95%. The specific surface area of E-2 is 1186 m 2 / g. The mesopore accounts for 50% of the total pore volume, the micropore accounts for 40% of the total pore volume, and the macropore accounts for 10% of the total pore volume.

[0046] The above product E-2 powder is pressed and sieved to obtain 20-40 mesh catalyst particles Cat2. A fixed bed reactor is used, 5 g of shaped catalyst Cat2 is loaded, at room temperature, benzene and methanol are mixed, gasified and uniformly dispersed at a molar ratio of 1:1, then enter the reactor, and the reaction is carried out at a reaction temperature of 500℃, normal pressure, benzene and methanol mass space velocity of 2.0 h -1 . After the reaction, a gas product stream is obtained, which is cooled and introduced into a gas-liquid separator for separation, and the liquid product is sampled and analyzed, and the test results are shown in Table 1. Example 3

[0047] Take 14.0 g of tetraethyl orthosilicate, 11.0 g of tetrapropylammonium hydroxide dissolved in 84 g of deionized water, stir evenly, then add 0.20 g of aluminum isopropoxide, stir evenly, form a transparent solution A-3. To A-3, add 15 mg of graphene oxide (thickness of 0.5 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-3, stir evenly, then ultrasonic in a ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-3, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 180℃ for 96 h. The obtained product is washed, suction filtered and dried at 100℃ for 12 h, then calcined at 650℃ for 6 h to obtain product D-3.

[0048] Take 10 g of product D-3, add 50 ml of 0.2 mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, suction filter and wash, then dry at 100℃ for 12 h to obtain the final product E-3. In the catalyst E-3, the molar ratio of SiO2 / Al2O is 140.

[0049] Product E-3 has a typical ZSM-5 molecular sieve structure, and the relative crystallinity is 92%. The specific surface area of E-3 is 1130 m 2 / g. The mesopore accounts for 60% of the total pore volume, the micropore accounts for 35% of the total pore volume, and the macropore accounts for 5% of the total pore volume.

[0050] The above product E-3 powder is pressed and sieved to obtain 20-40 mesh catalyst particles Cat3. A fixed bed reactor is used, 5 g of shaped catalyst Cat3 is loaded, at room temperature, benzene and methanol are mixed, gasified and dispersed uniformly at a molar ratio of 1:1, then enter the reactor, and the reaction is carried out at a reaction temperature of 500℃, normal pressure, benzene and methanol mass space velocity of 2.0 h -1 The gaseous product stream is obtained after the reaction, cooled and introduced into a gas-liquid separator for separation, and the liquid product is sampled and analyzed, and the test results are shown in Table 1. Example 4

[0051] Take 14.0 g of tetraethyl orthosilicate, 11.0 g of tetrapropylammonium hydroxide dissolved in 105 g of deionized water, stir evenly, then add 0.15 g of aluminum isopropylate, stir evenly, form a transparent solution A-4. To A-4, add 10 mg of graphene oxide (thickness of 0.5 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-4, stir evenly, then ultrasonic in a ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-4, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 180℃ for 96 h. The obtained product is washed, suction filtered, then dried at 100℃ for 12 h, and calcined at 650℃ for 6 h to obtain product D-4.

[0052] Take 10 g of product D-4, add 50 ml of 0.1 mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, suction filter and wash, then dry at 100℃ for 12 h to obtain the final product E-4. In the catalyst E-4, the molar ratio of SiO2 / Al2O is 180.

[0053] Product E-4 has a typical ZSM-5 molecular sieve structure, and the relative crystallinity is 85%. The specific surface area of E-4 is 1052 m 2 / g. The mesopore accounts for 52% of the total pore volume, the micropore accounts for 38% of the total pore volume, and the macropore accounts for 10% of the total pore volume.

[0054] The above product E-4 powder is pressed and sieved to obtain 20-40 mesh catalyst particles Cat4. A fixed bed reactor is used, 5 g of shaped catalyst Cat4 is loaded, at room temperature, benzene and methanol are mixed, gasified and dispersed uniformly at a molar ratio of 1:1, then enter the reactor, and the reaction is carried out at a reaction temperature of 500℃, normal pressure, benzene and methanol mass space velocity of 2.0 h -1 The gas product stream after reaction is cooled and introduced into a gas-liquid separator for separation, and the liquid product is sampled and analyzed, and the test results are shown in Table 1. Example 5

[0055] Take 14.0 g of tetraethyl orthosilicate, 7.35 g of tetrapropylammonium hydroxide dissolved in 42 g of deionized water, stir evenly, then add 0.16 g of aluminum isopropylate, stir evenly, form a transparent solution A-5. To A-5, add 15 mg of graphene oxide (thickness of 0.8 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-5, stir evenly, then ultrasonic in a ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-5, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 180℃ for 96 h. The obtained product is washed, suction filtered and dried at 100℃ for 12 h, then calcined at 650℃ for 6 h to obtain product D-5.

[0056] Take 10 g of product D-5, add 50 ml of 0.1 mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, suction filter and wash, then dry at 100℃ for 12 h to obtain the final product E-5. In the catalyst E-5, the molar ratio of SiO2 / Al2O is 175.

[0057] Product E-5 has a typical ZSM-5 molecular sieve structure, and the relative crystallinity is 90%. The specific surface area of E-5 is 1295 m 2 / g. The mesopore accounts for 50% of the total pore volume, the micropore accounts for 42% of the total pore volume, and the macropore accounts for 8% of the total pore volume.

[0058] The above product E-5 powder is pressed and sieved to obtain 20-40 mesh catalyst particles Cat5. A fixed bed reactor is used, 5 g of shaped catalyst Cat5 is loaded, at room temperature, benzene and methanol are mixed, gasified and dispersed uniformly at a molar ratio of 1:1, then enter the reactor, and the reaction is carried out at a reaction temperature of 500℃, normal pressure, benzene and methanol mass space velocity of 2.0 h -1 The gaseous product stream is obtained after the reaction, cooled and introduced into a gas-liquid separator for separation, and the liquid product is sampled and analyzed, and the test results are shown in Table 1. Example 6

[0059] Take 14.0 g of tetraethyl orthosilicate, 5.5 g of tetrapropylammonium hydroxide dissolved in 42 g of deionized water, stir evenly, then add 0.18 g of aluminum isopropoxide, stir evenly, form a transparent solution A-6. To A-6, add 15 mg of graphene oxide (thickness of 0.8 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-6, stir evenly, then ultrasonic in a ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-6, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 180℃ for 96 h. The obtained product is washed, suction filtered and dried at 100℃ for 12 h, then calcined at 550℃ for 4 h to obtain product D-6.

[0060] Take 10 g of product D-6, add 50 ml of 0.1 mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, suction filter and wash, then dry at 100℃ for 12 h to obtain the final product E-6. In the catalyst E-6, the molar ratio of SiO2 / Al2O is 155.

[0061] Product E-6 has a typical ZSM-5 molecular sieve structure, and the relative crystallinity is 90%. The specific surface area of E-6 is 1163 m 2 / g. The mesopore accounts for 53% of the total pore volume, the micropore accounts for 42% of the total pore volume, and the macropore accounts for 5% of the total pore volume.

[0062] The above product E-6 powder is pressed and sieved to obtain 20-40 mesh catalyst particles Cat6. A fixed bed reactor is used, 5 g of shaped catalyst Cat6 is loaded, at room temperature, benzene and methanol are mixed, gasified and dispersed uniformly at a molar ratio of 1:1, then enter the reactor, and the reaction is carried out at a reaction temperature of 500℃, normal pressure, benzene and methanol mass space velocity of 2.0 h -1 The gaseous product stream is obtained after the reaction, cooled and introduced into a gas-liquid separator for separation, and the liquid product is sampled and analyzed, and the test results are shown in Table 1. Example 7

[0063] Take 14.0 g of tetraethyl orthosilicate, 11.0 g of tetrapropylammonium hydroxide dissolved in 42 g of deionized water, stir evenly, then add 0.18 g of aluminum isopropylate, stir evenly, form a transparent solution A-7. To A-7, add 15 mg of graphene oxide (thickness of 0.5 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-7, stir evenly, then ultrasonic in a ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-7, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 180℃ for 48 h. The obtained product is washed, suction filtered and dried at 100℃ for 12 h, then calcined at 650℃ for 6 h to obtain product D-7.

[0064] Take 10 g of product D-7, add 50 ml of 0.1 mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, suction filter and wash, then dry at 100℃ for 12 h to obtain the final product E-7. In the catalyst E-7, the molar ratio of SiO2 / Al2O3 is 155.

[0065] Product E-7 has a typical ZSM-5 molecular sieve structure, and the relative crystallinity is 85%. The specific surface area of E-7 is 1180 m 2 / g. The mesopore accounts for 48% of the total pore volume, the micropore accounts for 42% of the total pore volume, and the macropore accounts for 10% of the total pore volume.

[0066] The above product E-7 powder is pressed and sieved to obtain 20-40 mesh catalyst particles Cat7. A fixed bed reactor is used, 5 g of shaped catalyst Cat7 is loaded, at room temperature, benzene and methanol are mixed, gasified and dispersed uniformly at a molar ratio of 1:1, then enter the reactor, and the reaction is carried out at a reaction temperature of 500℃, normal pressure, benzene and methanol mass space velocity of 2.0 h -1 The gaseous product stream is obtained after reaction, cooled and introduced into a gas-liquid separator for separation, and the liquid product is sampled and analyzed, and the test results are shown in Table 1. Example 8

[0067] Take 14.0 g of tetraethyl orthosilicate, 15.0 g of tetrabutylammonium hydroxide dissolved in 65 g of deionized water, stir evenly, then add 0.12 g of sodium aluminate, stir evenly, form a transparent solution A-8. Add 15 mg of graphene oxide (thickness of 0.5 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-8, stir evenly, then ultrasonic in the ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-8, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 160℃ for 72 h. The obtained product is washed, filtered and dried at 100℃ for 12 h, then calcined at 650℃ for 6 h to obtain product D-8.

[0068] Take 10 g of product D-8, add 50 ml of 0.1 mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, filter and wash, then dry at 100℃ for 12 h to obtain the final product E-8. The molar ratio of SiO2 / Al2O3 in the catalyst E-8 is 188.

[0069] The product E-8 has a typical ZSM-11 molecular sieve structure, and the relative crystallinity is 85%. The specific surface area of E-8 is 1180 m 2 / g. The mesopore accounts for 56% of the total pore volume, the micropore accounts for 40% of the total pore volume, and the macropore accounts for 4% of the total pore volume.

[0070] The above product E-8 powder is pressed and sieved to obtain 20-40 mesh catalyst particles Cat8. A fixed bed reactor is used, 5 g of shaped catalyst Cat8 is loaded, and benzene and methanol are mixed, vaporized and uniformly dispersed at a molar ratio of 1:1 at room temperature. The mixture is then introduced into the reactor, and the reaction is carried out at a reaction temperature of 500℃, atmospheric pressure, and a benzene and methanol mass space velocity of 2.0 h -1 The gaseous product stream is obtained after the reaction, cooled and introduced into a gas-liquid separator for separation, and the liquid product is sampled and analyzed. The test results are shown in Table 1. Comparative Example 1

[0071] Take 14.0 g of tetraethyl orthosilicate, 15.0 g of tetrabutylammonium hydroxide dissolved in 65 g of deionized water, stir evenly, then add 0.12 g of sodium aluminate, stir evenly, form a transparent solution A-8. Add 15 mg of graphene oxide (thickness of 0.5 nm) dispersed in 10 mL of ultrapure water to form a homogeneous solution B-8, stir evenly, then ultrasonic in the ultrasonic machine with a frequency of 20 kHz and a power of 2000 W for 30 s, record as solution C-8, then transfer the raw materials to a 100 mL polytetrafluoroethylene lined stainless steel autoclave, and place it in an oven at 160℃ for 72 h. The obtained product is washed, filtered and dried at 100℃ for 12 h, then calcined at 650℃ for 6 h to obtain product D-8.

[0072] Take 10g of product D-d1, add 50ml of 0.1mol / L lanthanum nitrate solution, stir at 40℃ for 4 hours, filter and wash, and dry at 100℃ for 12 hours to obtain the final product E-d1. The SiO2 / Al2O molar ratio in catalyst E-d1 is 140.

[0073] The XRD pattern of product E-d1 is shown below. Figure 1 It exhibits a typical ZSM-5 molecular sieve structure with a relative crystallinity of 90%. A scanning electron microscope image of product E-d1 can be found here. Figure 3 ,Depend on Figure 3 The molecular sieve can be seen to be columnar, and the specific surface area of ​​E-d1 is 539 m². 2 / g. The mesopores account for 4% of the total pore volume, and the micropores account for 96% of the total pore volume.

[0074] The above-mentioned product E-d1 powder was compressed into tablets and sieved to obtain 20-40 mesh catalyst particles DCat1. A fixed-bed reactor was used, with 5 g of the shaped catalyst DCat1 loaded. At room temperature, benzene and methanol were mixed in a molar ratio of 1:1, vaporized, and evenly dispersed before entering the reactor. The reaction was carried out at a reaction temperature of 500℃, atmospheric pressure, and a benzene-methanol mass hourly space velocity of 2.0 h⁻¹. -1 The reaction was carried out under certain conditions, and a gaseous product stream was obtained after the reaction. After cooling, the stream was passed into a gas-liquid separator for separation. The liquid product was sampled and analyzed. The test results are shown in Table 1. Comparative Example 2

[0075] The product D-1 powder prepared according to the method of Example 1 was compressed into tablets and sieved to obtain 20-40 mesh catalyst particles DCat2. Using a fixed-bed reactor, 5 g of the shaped catalyst DCat2 was loaded. At room temperature, benzene and methanol were mixed in a molar ratio of 1:1, vaporized, and uniformly dispersed before entering the reactor. The reaction was carried out at a reaction temperature of 500°C, atmospheric pressure, and a benzene-methanol mass hourly space velocity of 2.0 h⁻¹. -1 The reaction was carried out under certain conditions, and a gaseous product stream was obtained after the reaction. After cooling, the stream was passed into a gas-liquid separator for separation. The liquid product was sampled and analyzed. The test results are shown in Table 1.

[0076] Table 1. Evaluation results of catalyst performance

[0077] Sample Benzene conversion, % Toluene and xylene selectivity, % Selectivity to ethylbenzene, % Example 1 Cat 1 64.7 83.9 2.5 Example 2 Cat 2 64.2 83.5 2.2 Example 3 Cat 3 65.2 84.2 2.2 Example 4 Cat 4 64.2 84.1 2.5 Example 5 Cat 5 64.5 83.7 2.7 Example 6 Cat 6 64.1 83.1 2.8 Example 7 Cat 7 64.6 83.8 2.6 Example 8 Cat 8 62.9 81.3 3.2 Comparative Example 1 DCat 1 56.7 74.8 3.2 Comparative Example 2 DCat 2 Comparative Example 3 DCat 3 Comparative Example 4 DCat 4 Comparative Example 5 DCat 5 Comparative Example 6 DCat 6 Comparative Example 7 DCat 7 Comparative Example 8 DCat 8 62.4 78.2 8.1

[0078] The embodiments described above are merely illustrative of the detailed technical solutions of the present invention, but the present invention is not limited to the detailed technical solutions described above, that is, the present invention does not depend on the steps described in the above embodiments for implementation. In summary, any improvements made to the present invention by those skilled in the art, including the substitution of the raw materials and additives described in the present invention, the selection of specific implementation methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A benzene-methanol alkylation catalyst, comprising a graphene oxide-containing molecular sieve and a metal oxide, wherein the catalyst has a hierarchical porous column morphology; the catalyst simultaneously contains micropores, mesopores, and macropores, wherein the mesopores account for 30%-65% of the total pore volume, the micropores account for 30%-45% of the total pore volume, and the macropores account for 4%-15% of the total pore volume; the molecular sieve is a ZSM-5 molecular sieve; the metal in the metal oxide is selected from at least one of lanthanum, cerium, cobalt, manganese, copper, vanadium, titanium, platinum, or nickel; the graphene oxide-containing molecular sieve has a graphene oxide content of 0.01%-1.0% by mass; and the catalyst, based on the weight of the catalyst, has a graphene oxide-containing molecular sieve content of 70%-99% by mass and a metal oxide content of 1%-30% by mass.

2. The catalyst according to claim 1, characterized in that, The metal in the metal oxide is at least one of lanthanum and cerium.

3. The catalyst according to claim 1, characterized in that, In the graphene oxide-containing molecular sieve, the thickness of the graphene oxide is 0.4-1.0 nm; and / or, in the graphene oxide-containing molecular sieve, the mass content of the graphene oxide is 0.1%-0.5%.

4. The catalyst according to claim 3, characterized in that, In the graphene oxide-containing molecular sieve, the thickness of the graphene oxide is 0.5-0.8 nm.

5. The catalyst according to claim 1, characterized in that, In the catalyst, based on the weight of the catalyst, the mass content of the graphene oxide-containing molecular sieve is 80%-95%, and the mass content of the metal oxide is 5%-20%.

6. The catalyst according to claim 1, characterized in that, The catalyst has a relative crystallinity of 85%-120% and a specific surface area of ​​400-1300 m². 2 / g.

7. The catalyst according to claim 6, characterized in that, The catalyst has a specific surface area of ​​800-1300 m². 2 / g.

8. The catalyst according to claim 1, characterized in that, The catalyst has the morphology of a hierarchical porous column with a thickness of 300-1100 nm.

9. The catalyst according to claim 1, characterized in that, The mesopores account for 45%-61% of the total pore volume, the micropores account for 35%-45% of the total pore volume, and the macropores account for 4%-12% of the total pore volume.

10. A method for preparing the catalyst according to any one of claims 1-9, comprising: (1) Prepare a mixture by mixing silicon source, aluminum source, organic base template agent and water; (2) Mix the graphene oxide dispersion with the mixture prepared in step (1), crystallize, and obtain a molecular sieve containing graphene oxide; (3) The catalyst is prepared by loading a metal source onto a molecular sieve containing graphene oxide.

11. The preparation method according to claim 10, characterized in that, In step (1), the aluminum source is selected from one or more of sodium aluminate, boehmite, aluminum hydroxide, aluminum isopropoxide, aluminum sulfide, or aluminum powder; the silicon source is selected from one or more of tetraethyl orthosilicate, sodium silicate nonahydrate, silica sol, water glass, silica, or methyl orthosilicate; the organic base template agent is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide; wherein, the molar ratio of silicon source (SiO2), aluminum source (Al2O3), organic base template agent, and water is 1:0.005-0.033:0.1-1.0:12-150.

12. The preparation method according to claim 10, characterized in that, In step (2), the preparation method of the graphene oxide dispersion is as follows: dispersing graphene oxide in water and sonicating it to form a graphene oxide dispersion; wherein, the amount of graphene oxide used is 0.1-50 mg / 100 mL of aqueous solution, and the sonication conditions are as follows: frequency is 20-40 kHz, power is 1000-2000 W, and sonication time is 30 s-60 min.

13. The preparation method according to claim 10, characterized in that, In step (2), the crystallization conditions are as follows: the crystallization temperature is 120-220℃ and the crystallization time is 12-124 hours; and / or, in step (2), the crystallized material is dried and calcined to obtain the graphene oxide-containing molecular sieve; the drying conditions are as follows: the drying temperature is 40-150℃ and the drying time is 3-124 hours; the calcination conditions are as follows: the calcination temperature is 500-950℃ and the calcination time is 2-24 hours.

14. The preparation method according to claim 13, characterized in that, In step (2), the crystallization conditions are as follows: the crystallization temperature is 120-180℃ and the crystallization time is 6-48 hours; and / or, in step (2), the crystallized material is dried and calcined to obtain the graphene oxide-containing molecular sieve; the drying conditions are as follows: the drying temperature is 80-120℃ and the drying time is 12-48 hours; the calcination conditions are as follows: the calcination temperature is 550-800℃ and the calcination time is 4-10 hours.

15. The preparation method according to claim 10, characterized in that, In step (3), the metal source is loaded by at least one of impregnation or physical mixing followed by extrusion molding.

16. The use of the catalyst according to any one of claims 1-9 or the catalyst prepared by any one of claims 10-15 in the alkylation of benzene and methanol to prepare toluene and xylene.

17. The application according to claim 16, characterized in that, The reaction conditions for the alkylation of benzene and methanol are as follows: the molar ratio of benzene to methanol is 0.1-10, and the mass hourly space velocity (WHSV) of the reactants is 0.1-5.0 h⁻¹. -1 The reaction temperature is 350-500℃ and the reaction pressure is 0.1-1.0MPa.

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