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

Abstract

The application discloses a toluene and methanol alkylation catalyst and a preparation method and application thereof. The catalyst comprises ZSM-11 molecular sieves with special morphology and metal oxides, wherein the ZSM-11 molecular sieves have a morphology of a conical body particle formed by ordered accumulation of nanorods, and the conical body bottom surface is distributed with protrusions. The catalyst is used in a toluene and methanol alkylation reaction for preparing dimethylbenzene, greatly improves generation of toluene methylation product dimethylbenzene, inhibits isomerization of para-xylene, and improves selectivity of para-xylene.

Description

Technical Field

[0001] This invention belongs to the field of catalysis, specifically relating to a toluene and methanol alkylation catalyst, its preparation method, and its application. Background Technology

[0002] p-Xylene (PX) is an important organic chemical raw material, mainly used to prepare p-toluenedicarboxylic acid (PTA), which is then used to produce polyethylene terephthalate (PET). It can also be used as a solvent and a raw material in the pharmaceutical, fragrance, and ink industries, demonstrating its wide range of applications. Industrially, PX preparation technologies mainly include xylene disproportionation and alkyl transfer, xylene-methanol alkylation, xylene isomerization, and xylene adsorption separation. With the continuous increase in pure toluene production capacity, alkylation of toluene with inexpensive methanol not only expands the downstream applications of toluene but also generates high-value-added p-xylene.

[0003] Hierarchical porous ZSM-11 molecular sieves belong to the tetragonal crystal system and have a MEL topology. Although hierarchical porous ZSM-11 molecular sieves are structurally similar to ZSM-5 molecular sieves and belong to the Pentasil family, there are few reports on their synthesis, modification, and application in toluene and methanol alkylation.

[0004] CN 102746095A discloses a method for producing petroleum-grade xylene from toluene and methanol or dimethyl ether. This method employs a modified solid acid catalyst selected from at least one of ZSM-5, ZSM-12, mordenite, USY, β-zeolite, UZM-zeolite, EU-1-zeolite, or MCM-41-zeolite, containing at least one metallic element selected from Mg, Ga, Ba, Zn, Ga, Mo, Ni, Co, W, Cu, Fe, Zr, Ti, Pt, Pd, Sn, Pb, La, or Ce, and at least one non-metallic element selected from P, S, Cl, and B, to undergo an alkylation reaction to obtain xylene. CN 104437604A discloses a Mn-Ce-hierarchical porous ZSM-11 catalyst, its preparation method, and its application in the selective reduction of NO by NH3. Using a hierarchical porous ZSM-11 molecular sieve as a support, the active component Mn and the auxiliary agent Ce are impregnated onto the hierarchical porous ZSM-11 molecular sieve to prepare a supported Mn-Ce-hierarchical porous ZSM-11 catalyst. This type of catalyst, used in the NH3-SCR reaction of NO, achieved good activity and a wide reaction temperature window. Its catalytic activity under "sulfur-containing wet flue gas" conditions was significantly higher than that of the traditional Mn-Ce-ZSM-5 catalyst. CN 104098107B uses boron, aluminum, silicon, alkali, inorganic salts, template agents, and water as raw materials. Through crystallization, filtration, washing, drying, and calcination, a hierarchical porous ZSM-11 zeolite containing boron, aluminum, and silicon in its framework is synthesized in one step. The B-Al hierarchical porous ZSM-11 zeolite synthesized by this method is used to catalyze the methanol-to-propylene reaction, exhibiting higher propylene selectivity and a higher product P / E ratio compared to B-Al-ZSM-5 or hierarchical porous ZSM-11. CN 112156807A discloses a method for preparing hierarchical Zr-(H) hierarchical ZSM-11 molecular sieves. The method uses thermally activated composite-modified natural attapulgite as modified ATP, TPAOH as a template agent, and CTAB as a mesoporous directing agent. A certain amount of ZrOCl2·8H2O solution is added, and hierarchical Zr-(H) hierarchical ZSM-11 molecular sieves are directly synthesized using an in-situ hydrothermal crystallization method. This catalyst can synthesize photocatalytic materials with strong photocatalytic performance, high photocatalytic efficiency, microporous and mesoporous pores, and large specific surface area. It is also simple to operate, environmentally friendly, and can be recycled multiple times. It plays a significant role in the degradation of azo dyes in dyeing and printing wastewater.CN101722035B describes a catalyst with shape-selective properties, comprising, by weight, the following components: a) 5-95 parts of core-shell molecular sieve material, b) 5-95 parts of binder. The core phase of the core-shell molecular sieve is selected from ZSM-5, hierarchical ZSM-11, ZSM-35, ZSM-48, β-carboxylic zeolite, MCM-22, or aluminosilicate molecular sieve. The shell molecular sieve consists of continuous, dense ZSM-5 crystals. This method can be used in the industrial production of xylene selective disproportionation and xylene methylation of aromatics. CN103121912A discloses a method for producing xylene through methylation and alkyl transfer, primarily addressing the problem in existing xylene disproportionation or xylene disproportionation and alkyl transfer technologies that the xylene yield is determined by the ring ratio of methyltoluene in the feedstock, resulting in low xylene production and the simultaneous generation of large amounts of toluene as a byproduct when heavy aromatic feedstock is insufficient. This method uses methanol and C... 12 Using aromatic hydrocarbons containing little or no xylene as raw materials, the reaction is carried out at a temperature of 300-500℃, a reaction pressure of atmospheric pressure to 10.0 MPa, and a feed weight hourly space velocity of 0.3-10 h⁻¹. 1 Under certain conditions, the raw materials come into contact with a solid acid catalyst, causing methanol and aromatics to undergo an alkylation reaction on the catalyst, while alkyl transfer occurs between the aromatics to obtain xylene products.

[0005] Currently, the main problems in the industrial synthesis of xylene are the low conversion rate of toluene and the high content of ethyltoluene byproducts, which leads to low selectivity of the target product and makes it impossible to simultaneously guarantee the conversion rate of toluene and the selectivity of xylene. Summary of the Invention

[0006] To address the problems of low toluene conversion, low selectivity of target products, and high content of ethylbenzene byproducts in the alkylation of toluene and methanol to prepare xylene in existing technologies, this invention provides a catalyst for the alkylation reaction of toluene and methanol, its preparation method, and its application. The catalyst of this invention, used in the alkylation reaction of toluene and methanol to prepare xylene, features high toluene conversion, high selectivity for xylene and p-xylene, and low content of ethylbenzene byproducts.

[0007] The first aspect of this invention provides a toluene and methanol alkylation catalyst, comprising a ZSM-11 molecular sieve and a metal oxide; the ZSM-11 molecular sieve is in the form of cone-shaped particles formed by orderly stacking of nanorods, with a particle size of 500 nm to 2 μm and a radial dimension of 20 to 60 nm for the nanorods, and the bottom surface of the cone has protrusions with a size of 100 to 300 nm; the metal oxide is selected from at least one of Group IIA, Group IVA, Group VA, Group IIIB, Group IVB, Group VIB, and Group VIII of the periodic table.

[0008] In the above technical solution, the content of the metal oxide in the catalyst, based on the mass of ZSM-11 molecular sieve, is 0.1% to 30%, preferably 0.5% to 10%.

[0009] In the above technical solution, the Group IIA metal is selected from at least one of Mg, Ca, and Ba; the Group IVA metal is selected from at least one of Sn and Pb; the Group VA metal is Bi; the Group IIIB metal is selected from at least one of La and Ce; the Group IVB metal is selected from at least one of Zr and Ti; the Group VIB metal is Mo; and the Group VIII metal is selected from at least one of Fe, Co, Ni, Cu, Pt, and Pd. Preferably, the metal is selected from at least one of La, Ce, Co, Mg, and Ba.

[0010] In the above technical solution, the size of the cone-shaped particles is preferably 800 nm to 1.5 μm; the radial dimension of the nanorod is preferably 30 to 50 nm; and the size of the protrusion is preferably 100 to 200 nm. The protrusion is ice crystal shaped.

[0011] In the above technical solution, the ZSM-11 molecular sieve is formed by the orderly stacking of nanorods into conical particles, which are then stacked in a secondary manner. Preferably, in the secondary stacking, the conical particles are stacked with their bottom surfaces facing outwards and their apexes facing inwards.

[0012] In the above technical solution, the ZSM-11 molecular sieve has a multi-level pore structure of micropores and mesopores, with the mesopore diameter being 10-50 nm.

[0013] In the above technical solution, the specific surface area of ​​the ZSM-11 molecular sieve is 325–516 m². 2 / g, pore volume is 0.29~0.59cm³ 3 / g, preferably 0.45~0.59cm 3 / g, mesoporous pore volume is 0.30~0.52cm³ 3 / g.

[0014] A second aspect of the present invention provides a method for preparing the above-mentioned toluene-methanol alkylation catalyst, comprising:

[0015] (1) Mix the first aluminum source, the first alkali source, the first template agent, the structural aid and water to obtain solution A; mix the first silicon source with solution A to obtain an initial gel, and crystallize it to obtain ZSM-11 molecular sieve seed crystals;

[0016] (2) Mix the second aluminum source, the second alkali source, the second template agent, the second silicon source and water to obtain solution B. Mix solution B with the ZSM-11 molecular sieve seed crystal obtained in step (1), and then crystallize, dry and calcine to obtain ZSM-11 molecular sieve.

[0017] (3) Load the metal onto the ZSM-11 molecular sieve obtained in step (2), shape it, and obtain the catalyst.

[0018] In the above technical solution, the method for preparing the catalyst includes:

[0019] (1) First, mix the first aluminum source, the first alkali source and water to obtain solution A; mix the first silicon source with solution A, and then add the first template agent and the structural aid to obtain the initial gel. After crystallization, ZSM-11 molecular sieve seed crystals are obtained.

[0020] (2) First, mix the second aluminum source, the second alkali source and water to obtain solution B. Mix solution B with the ZSM-11 molecular sieve seed crystal obtained in step (1), then add the second template agent. After crystallization, drying and calcination, ZSM-11 molecular sieve is obtained.

[0021] (3) Load the ZSM-11 molecular sieve obtained in step (2) with metal, shape it, and obtain the catalyst.

[0022] In the above technical solution, the structural additive is selected from at least one of hexadecyltrimethylammonium bromide (CTAB) or polydiallyldimethylammonium chloride (PDDA).

[0023] In the above technical solution, the first template agent or the second template agent is independently selected from at least one of tetrabutylammonium hydroxide (TBAOH), tetrabutylammonium bromide (TBABr), and 1,8-octanoic acid diammonium.

[0024] In the above technical solution, the first silicon source or the second silicon source is independently selected from at least one of tetraethyl orthosilicate (TEOS), sodium silicate, atomized silica gel, or silica sol.

[0025] In the above technical solution, the first aluminum source or the second aluminum source is independently selected from at least one of boehmite, aluminum nitrate, sodium aluminate, aluminum sulfate or aluminum isopropoxide.

[0026] In the above technical solution, the first alkali source or the second alkali source is independently selected from at least one of sodium hydroxide or potassium hydroxide.

[0027] In the above technical solution, in step (1), the molar ratios of the first aluminum source (calculated as Al2O3), the first silicon source (calculated as SiO2), the first alkali source (calculated as oxide (M2O, where M represents alkali metal ions), the first template agent, and water are as follows: 1SiO2: (0.10~1.0) First template agent: (0.01~0.005)Al2O3: (0.005~0.02)M2O: (80~200)H2O In the above technical solution, in step (1), the amount of the structural additive added is 10%~70% of the mass of the first silicon source (calculated as SiO2).

[0028] In the above technical solution, in step (1), the mixing conditions for preparing solution A are as follows: the temperature is 30-120℃, preferably 40-90℃, and the stirring time is 2-12 hours, preferably 2-8 hours.

[0029] In the above technical solution, the crystallization conditions in step (1) are as follows: the crystallization temperature is 140-220℃, preferably 150-180℃, and the crystallization time is 24-96 hours, preferably 48-96 hours.

[0030] In the above technical solution, in step (1), after crystallization, conventional steps such as separation and washing are performed first, and then the separated seed crystals are immediately placed in deionized water for storage. The separation can be performed by centrifugation. The washing can be performed by washing with deionized water until the pH value is 8-9.

[0031] In the above technical solution, in step (2), the molar ratios of the second aluminum source (calculated as Al2O3), the second silicon source (calculated as SiO2), the second alkali source (calculated as oxide (M2O, where M represents alkali metal ions), the second template agent, and water are as follows: 1SiO2: (0.20~1.0) Second template agent: (0.02~0.005)Al2O3: (0.005~0.02)M2O: (100~200)H2O.

[0032] In the above technical solution, in step (2), the amount of ZSM-11 molecular sieve seed crystals added is 1% to 10% of the mass of the second silicon source based on SiO2.

[0033] In the above technical solution, in step (2), the mixing conditions for preparing solution B are as follows: the temperature is 30-120℃, preferably 40-90℃, and the stirring time is 2-12 hours, preferably 2-8 hours.

[0034] In the above technical solution, in step (2), the crystallization is a two-stage crystallization, and the crystallization conditions are as follows: the first-stage crystallization temperature is 30-60°C lower than the crystallization temperature in step (1), and the first-stage crystallization time is 12-60 hours, preferably 12-48 hours; the second-stage crystallization temperature is 30-60°C higher than the first-stage crystallization temperature, and the second-stage crystallization time is 12-60 hours, preferably 24-48 hours.

[0035] In the above technical solution, the drying conditions in step (2) are as follows: the drying temperature is 60-175℃, preferably 80-130℃, and the drying time is 3-124 hours, preferably 10-48 hours. The calcination conditions are as follows: the calcination temperature is 500-800℃, preferably 530-650℃, and the calcination time is 3-12 hours, preferably 4-8 hours.

[0036] In the above technical solution, after crystallization in step (2), conventional steps such as separation and washing can be performed. The separation can be performed by centrifugation. The washing can be performed with deionized water until the pH value is 8-9.

[0037] In the above technical solution, in step (3), the ZSM-11 molecular sieve undergoes ammonium exchange before being impregnated with metal, and the ammonium exchange adopts a conventional method.

[0038] In the above technical solution, after impregnation in step (3), conventional steps such as separation, washing, and drying can be performed. The molding method can be prepared using commonly known catalyst molding methods in the art, such as granulation and extrusion molding.

[0039] In the above technical solution, in step (3), the metal is selected from at least one of Group IIA, Group IVA, Group VA, Group IIIB, Group IVB, Group VIB, and Group VIII of the periodic table. Specifically, the Group IIA metal is selected from at least one of Mg, Ca, and Ba; the Group IVA metal is selected from at least one of Sn and Pb; the Group VA metal is Bi; the Group IIIB metal is selected from at least one of La and Ce; the Group IVB metal is selected from at least one of Zr and Ti; the Group VIB metal is Mo; and the Group VIII metal is selected from at least one of Fe, Co, Ni, Cu, Pt, and Pd. Preferably, the metal is at least one of La, Ce, Co, Mg, and Ba.

[0040] In the above technical solution, in step (3), the metal source can be a soluble compound. For example, the compound of Group IIA metals is selected from one or more of nitrates, chlorates, high chloric acid, acetates, and halides; the compound of Group IVA metals is selected from one or more of ortho-acid salts, meta-acid salts, or digermanium salts; the compound of Group VA metals is selected from one or more of BiCl3, Bi(NO3)3·5H2O, or bismuthates; the compound of Group IIIB metals is selected from nitrates or chlorides of La and Ce; the compound of Group IVB metals is selected from nitrates; the compound of Group VIB metals is selected from molybdates; and the compound of Group VIII metals is selected from one or more of chlorides, nitrates, and sulfates.

[0041] In the above technical solution, in step (3), the concentration of the metal source, calculated as oxide, is 0.01 to 1 mol / L.

[0042] In the above technical solution, in step (3), based on the mass of ZSM-11 molecular sieve, the amount of metal source added, calculated as oxide, is 3% to 60%, preferably 5% to 40%.

[0043] A third aspect of the present invention provides the application of the above-mentioned catalyst in the preparation of xylene and p-xylene by the alkylation reaction of toluene and methanol.

[0044] In the above technical solution, the reaction conditions are as follows: the molar ratio of toluene to methanol is 0.1 to 10, the reaction temperature is 300 to 600°C, and the reaction pressure is 0 to 1.0 MPa.

[0045] In the above technical solution, the weight ratio of toluene to methanol is 1 to 30 h. -1 The carrier gas that carries the reactants into the catalyst bed is an inert gas, and the molar ratio of the carrier gas to the mixed feedstock is 5 to 20.

[0046] In the above technical solution, the inert gas is one of nitrogen, hydrogen, or argon.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. This invention provides a toluene and methanol alkylation catalyst, comprising a ZSM-11 molecular sieve with a special morphology and a metal oxide. The ZSM-11 molecular sieve consists of ordered, primary stacking of nanorods into conical particles, with the secondary stacking of these conical particles arranged such that the bottom surface faces outwards and the apex faces inwards, and protrusions are distributed on the bottom surface. Using this catalyst in the toluene and methanol alkylation reaction to prepare xylene and para-xylene, the benzene conversion rate reaches over 50%, the xylene selectivity reaches over 85%, and the para-xylene selectivity reaches over 55%, demonstrating promising application prospects.

[0049] 2. The catalyst of this invention first uses a structural aid to assist in the secondary crystallization process to prepare a ZSM-11 molecular sieve with a special morphology, and finally loads a metal. The catalyst prepared by this method exhibits high toluene conversion and high selectivity for xylene and p-xylene in the alkylation reaction of toluene and methanol, while effectively reducing the content of byproducts such as ethylbenzene. Attached Figure Description

[0050] Figure 1 This is the XRD pattern of the ZSM-11 molecular sieve obtained in Example 1 of the present invention;

[0051] Figure 2 This is a SEM image of the ZSM-11 molecular sieve obtained in Example 1 of this invention;

[0052] Figure 3 This is the nitrogen adsorption-desorption isotherm of the ZSM-11 molecular sieve obtained in Example 1 of this invention;

[0053] Figure 4 This is the mesopore distribution curve of the ZSM-11 molecular sieve obtained in Example 1 of the present invention;

[0054] Figure 5 This is a SEM image of the ZSM-11 molecular sieve obtained in Comparative Example 1 of this invention. Detailed Implementation

[0055] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0056] The crystal structure of the samples was analyzed using a Bruker D8 Advance X-ray diffractometer (XRD) with a Cu Kα target, λ = 0.1542 nm, tube voltage of 40 kV, and tube current of 50 mA. The relative crystallinity of the post-processed samples was calculated by dividing the peak area of ​​the parent sample at 2θ = 9.3° by 100% and the peak area of ​​other samples at the same location.

[0057] Crystal morphology was determined using a Zeiss Merlin scanning electron microscope (SEM) with an accelerating voltage of 2 kV. The sample was uniformly dispersed on a sample stage coated with conductive adhesive for testing.

[0058] The specific surface area and pore structure of the samples were determined using a Micromeritics ASAP 2020M physical adsorption instrument. Before testing, the samples were degassed under vacuum at 350℃ for 4 hours, and the specific surface area of ​​the samples was calculated using the BET method.

[0059] In this invention, the toluene / methanol alkylation to xylene and p-xylene reactions were carried out in an atmospheric pressure fixed-bed flow reactor. The products were analyzed using an Agilent 8890A gas chromatograph (GC). The product gas mixture was periodically analyzed using a gas chromatograph equipped with a flame ionization detection (FID) device and an HP-PONA capillary column (50 m × 0.2 mm × 0.5 μm). The oven temperature was maintained at 343 K.

[0060]

Example 1

[0061] 0.164 g of sodium aluminate and 0.058 g of potassium hydroxide were dissolved in 158.0 g of deionized water to form a clear solution. 20.8 g of TEOS was added to this solution, and the mixture was stirred to form a homogeneous clear solution. Then, 9.48 g of tetrabutylammonium hydroxide (TBAOH) and 10.4 g of cetyltrimethylammonium bromide (CTAB) were added as template agents. The mixture was stirred at 60 °C for 8 hours, transferred to a reaction vessel, and crystallized at 170 °C for 48 hours. After rapid cooling, centrifugation, and washing, the separated seed crystals were immediately placed in deionized water and stored, named A-1.

[0062] 0.164 g of sodium aluminate and 0.058 g of potassium hydroxide were dissolved in 255.8 g of deionized water to form a transparent solution. 20.75 g of TEOS was added to this solution, followed by 6.48 g of tetrabutylammonium hydroxide (TBAOH) as a template agent. The mixture was stirred at 60 °C for 2 hours. 0.6 g of A-1 was added, and the mixture was stirred for 1 hour. The mixture was then transferred to a reactor and crystallized at 140 °C for 12 hours, followed by further crystallization at 180 °C for 24 hours. The mixture was then rapidly cooled, centrifuged, dried at 100 °C for 10 hours, and calcined at 550 °C for 6 hours to obtain an ammonium-type molecular sieve. The obtained ammonium-type molecular sieve was then exchanged with a 0.1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:50 at 80 °C for 4 hours. This process was repeated three times. After filtration, washing, and drying, H-type molecular sieve B-1 was obtained.

[0063] 5g of B-1 was impregnated in 100ml of 0.1mol / L La(NO3)3 solution for 3 hours, then filtered, washed and dried, extruded into strips and crushed to 20-40 mesh. The resulting catalyst was denoted as Cat1.

[0064] The catalyst Cat1 contains 8.4% La2O3.

[0065] From the XRD pattern of product B-1 above ( Figure 1 As can be seen, it has a typical ZSM-11 molecular sieve structure with a specific surface area of ​​464 m². 2 / g, pore volume 0.57cm 3 / g, mesoporous pore volume is 0.46cm³ 3 / g, with a mesopore size of 4.47nm. (Scanning electron microscope image of B-1) Figure 2 As can be seen, the morphology of the molecular sieve is that the nanorods are stacked in an orderly manner from the bottom to the top of the cone to form cone-shaped particles with a particle size of 800 nm to 1 μm and a radial dimension of 40 to 50 nm for the nanorods. The bottom surface of the cone has protrusions with a size of 100 to 150 nm. The cone particles are stacked in a secondary manner with the bottom facing outward and the top facing inward.

[0066] A fixed-bed reactor was used, loaded with 3g of shaped catalyst Cat1. Toluene and methanol were mixed at a molar ratio of 1:1, vaporized, and uniformly dispersed at room temperature before entering the reactor. The reaction was carried out at a temperature of 480℃, with nitrogen as the carrier gas (molar ratio of nitrogen to the mixed feedstock was 1:3), a pressure of 0.05MPa, and a weight hourly space velocity (WHSV) of 2.0h⁻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. See Table 1 for details.

[0067]

Example 2

[0068] 0.164 g of sodium aluminate and 0.058 g of potassium hydroxide were dissolved in 70.8 g of deionized water to form a clear solution. 20.8 g of TEOS was added to this solution, and the mixture was stirred to form a homogeneous clear solution. Then, 5.66 g of 1,8-octanediamine and 10.4 g of hexadecyltrimethylammonium bromide (CTAB) were added. The mixture was stirred at 60 °C for 8 hours, transferred to a reaction vessel, and crystallized at 165 °C for 48 hours. After rapid cooling, centrifugation, and washing, the separated seed crystals were immediately placed in deionized water and stored, named A-2.

[0069] 0.164 g of sodium aluminate and 0.058 g of potassium hydroxide were dissolved in 255.8 g of deionized water to form a clear solution. 20.75 g of TEOS was added to this solution, followed by 5.66 g of 1,8-octanediamine. The mixture was stirred at 60 °C for 2 hours. 0.6 g of A-2 was added, and the mixture was stirred for 1 hour. The mixture was then transferred to a reaction vessel and crystallized at 135 °C for 12 hours. The temperature was then raised to 180 °C and crystallized for another 24 hours. The mixture was rapidly cooled, centrifuged, dried at 100 °C for 10 hours, and calcined at 550 °C for 6 hours to obtain an ammonium-type molecular sieve. The obtained ammonium-type molecular sieve was then exchanged with a 0.1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:50 at 80 °C for 4 hours. This process was repeated three times. After filtration, washing, and drying, H-type molecular sieve B-2 was obtained.

[0070] 5g of B-2 was soaked in 100ml of 0.1mol / L Ce(NO3)3 solution for 3 hours, then filtered, washed and dried, extruded into strips, and crushed to 20-40 mesh, and recorded as Cat2.

[0071] The CeO content in catalyst Cat2 is 7.2%.

[0072] The XRD pattern of product B-2 above is similar to Figure 1 Similarly, it has a typical ZSM-11 molecular sieve structure with a specific surface area of ​​504 m². 2 / g, pore volume 0.53cm 3 / g, mesoporous pore volume is 0.45cm³ 3 / g, with a mesopore size of 5.32nm. The morphology of B-2 is similar to... Figure 2 Similarly, the nanorods are orderedly stacked along the bottom to the top of the cone to form cone-shaped particles with a particle size of 800 nm to 1.3 μm and a radial dimension of 30 to 45 nm. The bottom surface of the cone has protrusions with a size of 100 to 200 nm. The cone particles are stacked in a secondary manner with the bottom facing outward and the top facing inward.

[0073] A fixed-bed reactor was used, loaded with 3g of shaped catalyst Cat2. Toluene and methanol were mixed at a molar ratio of 1:1, vaporized, and evenly dispersed at room temperature before entering the reactor. The reaction was carried out at a temperature of 480℃, with nitrogen as the carrier gas (molar ratio of nitrogen to the mixed feedstock was 1:3), a pressure of 0.05MPa, and a weight hourly space velocity (WHSV) of 2.0h⁻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. Its technical indicators are listed in Table 1.

[0074]

Example 3

[0075] 0.10 g of sodium aluminate and 0.058 g of potassium hydroxide were dissolved in 180.8 g of deionized water to form a clear solution. 20.8 g of TEOS was added to this solution, and the mixture was stirred to form a homogeneous clear solution. Then, 9.48 g of tetrabutylammonium hydroxide (TBAOH) and 10.4 g of cetyltrimethylammonium bromide (CTAB) were added as template agents. The mixture was stirred at 60 °C for 8 hours, transferred to a reaction vessel, and crystallized at 175 °C for 48 hours. After rapid cooling, centrifugation, and washing, the separated seed crystals were immediately placed in deionized water and stored, named A-3.

[0076] 0.10 g of sodium aluminate and 0.058 g of potassium hydroxide were dissolved in 179.2 g of deionized water to form a clear solution. 20.75 g of TEOS was added to this solution, followed by 12.68 g of tetrabutylammonium hydroxide (TBAOH) as a template agent. The mixture was stirred at 60 °C for 2 hours. 0.6 g of A-3 was added, and the mixture was stirred for 1 hour. The mixture was then transferred to a reactor and crystallized at 140 °C for 48 hours. The temperature was then raised to 180 °C for another 24 hours of crystallization. The mixture was rapidly cooled, centrifuged, dried at 100 °C for 10 hours, and calcined at 550 °C for 6 hours to obtain an ammonium-type molecular sieve. The obtained ammonium-type molecular sieve was then exchanged with a 0.1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:50 at 80 °C for 4 hours. This process was repeated three times. After filtration, washing, and drying, H-type molecular sieve B-3 was obtained.

[0077] 5g of B-3 was impregnated in 100ml of 0.5mol / L Mg(NO3)2 solution for 3 hours, then filtered, washed and dried, extruded into strips and crushed to 20-40 mesh. The resulting catalyst was denoted as Cat3.

[0078] The MgO content in catalyst Cat3 is 0.5%.

[0079] The XRD pattern of the above product B-3 is similar to Figure 1 Similarly, it has a typical ZSM-11 molecular sieve structure with a specific surface area of ​​386 m². 2 / g, pore volume 0.52cm 3 / g, mesoporous pore volume is 0.36cm³ 3 / g, with a mesopore size of 3.49nm. The morphology of B-3 is that of cone-shaped particles formed by the orderly stacking of nanorods from the bottom to the top of the cone, with a particle size of 900nm to 1.3μm and a radial dimension of 35 to 45nm for the nanorods; protrusions with a size of 100 to 170nm are distributed on the bottom surface of the cone; the cone particles are stacked in a secondary manner with the bottom surface facing outward and the top surface facing inward.

[0080] A fixed-bed reactor was used, loaded with 3g of shaped catalyst Cat3. Toluene and methanol were mixed at a molar ratio of 1:1, vaporized, and evenly dispersed at room temperature before entering the reactor. The reaction was carried out at a temperature of 480℃, with nitrogen as the carrier gas (molar ratio of nitrogen to the mixed feedstock was 1:3), a pressure of 0.05MPa, and a weight hourly space velocity (WHSV) of 2.0h⁻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. Its technical indicators are listed in Table 1.

[0081]

Example 4

[0082] 0.12 g of sodium aluminate and 0.08 g of NaOH were dissolved in 180.6 g of deionized water to form a clear solution. 20.8 g of TEOS was added to this solution, and the mixture was stirred to form a homogeneous clear solution. Then, 9.60 g of tetrabutylammonium bromide and 10.4 g of hexadecyltrimethylammonium bromide (CTAB) were added as template agents. The mixture was stirred at 65 °C for 8 hours, transferred to a reaction vessel, and crystallized at 180 °C for 48 hours. After rapid cooling, centrifugation, and washing, the separated seed crystals were immediately placed in deionized water and stored, named A-4.

[0083] 0.12 g of sodium aluminate and 0.01 g of potassium hydroxide were dissolved in 180 g of deionized water to form a clear solution. 20.75 g of TEOS was added to this solution, followed by 9.60 g of the template agent tetrabutylammonium bromide. The mixture was stirred at 60 °C for 2 hours. 0.8 g of A-4 was added, and the mixture was stirred for 1 hour. The mixture was then transferred to a reaction vessel and crystallized at 130 °C for 24 hours, followed by further crystallization at 160 °C for 48 hours. The mixture was then rapidly cooled, centrifuged, dried at 100 °C for 10 hours, and calcined at 550 °C for 6 hours to obtain an ammonium-type molecular sieve. The obtained ammonium-type molecular sieve was then exchanged with a 0.1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:50 at 80 °C for 4 hours. This process was repeated three times. After filtration, washing, and drying, H-type molecular sieve B-4 was obtained.

[0084] 5g of B-4 was soaked in 200ml of 0.1mol / L Co(NO3)2 solution for 3 hours, then filtered, washed and dried, extruded into strips, and crushed to 20-40 mesh, and recorded as Cat4.

[0085] The CoO content in catalyst Cat4 is 1.3%.

[0086] The XRD pattern of the above product B-4 is similar to Figure 1 Similarly, it has a typical ZSM-11 molecular sieve structure with a specific surface area of ​​413 m². 2 / g, pore volume is 0.47cm 3 / g, mesoporous pore volume is 0.50cm³ 3 / g, with a mesopore size of 5.21nm. The morphology of the molecular sieve B-4 is that of cone-shaped particles formed by the orderly stacking of nanorods from the bottom to the top of the cone, with a particle size of 900nm to 1.2μm and a radial dimension of 40 to 50nm for the nanorods; protrusions with a size of 110 to 130nm are distributed on the bottom surface of the cone; the cone particles are stacked in a secondary manner with the bottom surface facing outward and the top surface facing inward.

[0087] A fixed-bed reactor was used, loaded with 3g of shaped catalyst Cat4. Toluene and methanol were mixed at a molar ratio of 1:1, vaporized, and evenly dispersed at room temperature before entering the reactor. The reaction was carried out at a temperature of 480℃, with nitrogen as the carrier gas (molar ratio of nitrogen to the mixed feedstock was 1:3), a pressure of 0.05MPa, and a weight hourly space velocity (WHSV) of 2.0h⁻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. Its technical indicators are listed in Table 1.

[0088]

Example 5

[0089] 0.068 g NaOH was dissolved in 255.8 g deionized water. 0.75 g aluminum nitrate was added and stirred until dissolved, forming a clear solution. 20.8 g TEOS was added, followed by 7.5 g tetrabutylammonium bromide. After thorough stirring, 9.4 g polydiallyldimethylammonium chloride was added. The mixture was then transferred to a 100 ml stainless steel autoclave lined with polytetrafluoroethylene. The mixture was stirred at 60 °C for 8 hours. The mixture was then transferred to a reaction vessel and crystallized at 170 °C for 48 hours. After rapid cooling, centrifugation, and washing, the separated seed crystals were immediately placed in deionized water and stored, named A-5.

[0090] 0.75 g of aluminum nitrate and 0.068 g of potassium hydroxide were dissolved in 255.8 g of deionized water to form a transparent solution. 20.75 g of TEOS was added to this solution, followed by 7.5 g of tetrabutylammonium bromide as a template agent. The mixture was stirred at 60 °C for 2 hours. 0.6 g of A-5 was added, and the mixture was stirred for 1 hour. The mixture was then transferred to a reaction vessel and crystallized at 140 °C for 12 hours, followed by further crystallization at 180 °C for 24 hours. The mixture was then rapidly cooled, centrifuged, dried at 100 °C for 10 hours, and calcined at 550 °C for 6 hours to obtain an ammonium-type molecular sieve. The obtained ammonium-type molecular sieve was then exchanged with a 0.1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:50 at 80 °C for 4 hours. This process was repeated three times. After filtration, washing, and drying, H-type molecular sieve B-5 was obtained.

[0091] 5g of B-5 was soaked in 100ml of 0.1mol / L Ce(NO3)3 solution for 3 hours, then filtered, washed and dried, extruded into strips, and crushed to 20-40 mesh, and recorded as Cat5.

[0092] The CeO content in catalyst Cat5 is 7.3%.

[0093] The aforementioned product B-5 has a typical ZSM-11 molecular sieve structure and a specific surface area of ​​394 m². 2 / g, pore volume 0.54cm 3 / g, mesoporous pore volume is 0.47cm³ 3 / g, with a mesopore size of 4.98nm. The morphology of B-5 is that of cone-shaped particles formed by the orderly stacking of nanorods from the bottom to the top of the cone, with a particle size of 800nm ​​to 1300nm and a radial dimension of 40 to 60nm for the nanorods; protrusions with a size of 130 to 180nm are distributed on the bottom surface of the cone; the cone particles are stacked in a secondary manner with the bottom surface facing outward and the top surface facing inward.

[0094] A fixed-bed reactor was used, loaded with 3g of shaped catalyst Cat5. Toluene and methanol were mixed at a molar ratio of 1:1, vaporized, and evenly dispersed at room temperature before entering the reactor. The reaction was carried out at a temperature of 480℃, with nitrogen as the carrier gas (molar ratio of nitrogen to the mixed feedstock was 1:3), a pressure of 0.05MPa, and a weight hourly space velocity (WHSV) of 2.0h⁻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. Its technical indicators are listed in Table 1.

[0095]

Example 6

[0096] 0.06 g of sodium aluminate was added to 0.0786 g of sodium hydroxide solution and 153.66 g of deionized water to form a transparent solution. 9.707 g of silicon source TEOS was added to this solution and stirred to form a homogeneous transparent solution. Then, 5.925 g of TBAOH was added, followed by 5.0 g of PDDA. The resulting mixture was stirred at 80 °C for 2 hours to hydrolyze tetraethyl orthosilicate. The resulting solution was transferred to a 100 ml reactor and crystallized at 180 °C for 72 hours. After cooling, centrifugation, and washing, the separated seed crystals were immediately placed in deionized water and stored, named A-6.

[0097] 0.220 g of sodium aluminate was added to 0.0786 g of sodium hydroxide solution and 153.6 g of deionized water to form a transparent solution. 9.707 g of silicon source TEOS was added to this solution, followed by 5.925 g of TBAOH. The mixture was stirred at 60 °C for 2 hours, then 0.6 g of A-6 was added, and the mixture was stirred for 1 hour. The mixture was then transferred to a reactor and crystallized at 130 °C for 48 hours, followed by a constant temperature of 160 °C for 48 hours. After rapid cooling, the mixture was centrifuged, dried at 100 °C for 10 hours, and calcined at 550 °C for 6 hours to obtain an ammonium-type molecular sieve. The obtained ammonium-type molecular sieve was then exchanged with a 0.1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:50 at 80 °C for 4 hours. This process was repeated three times. After filtration, washing, and drying, H-type molecular sieve B-6 was obtained.

[0098] 5g of B-6 was soaked in 100ml of 0.1mol / L Ba(NO3)2 solution for 3 hours, then filtered, washed and dried, extruded into strips, and crushed to 20-40 mesh, and recorded as Cat6.

[0099] The catalyst Cat6 contains 3.2% BaO.

[0100] The aforementioned product B-6 has a typical ZSM-11 molecular sieve structure and a specific surface area of ​​404 m². 2 / g, pore volume 0.52cm 3 / g, mesoporous pore volume is 0.48cm³ 3 / g, with a mesopore size of 5.57nm. The morphology of B-6 is that of cone-shaped particles formed by the orderly stacking of nanorods from the bottom to the top of the cone, with a particle size of 900nm to 1.4μm and a radial dimension of 30 to 50nm for the nanorods; protrusions with a size of 100 to 200nm are distributed on the bottom surface of the cone; the cone particles are stacked in a secondary manner with the bottom surface facing outward and the top surface facing inward.

[0101] A fixed-bed reactor was used, loaded with 3g of shaped catalyst Cat6. Toluene and methanol were mixed at a molar ratio of 1:1, vaporized, and evenly dispersed at room temperature before entering the reactor. The reaction was carried out at a temperature of 480℃, with nitrogen as the carrier gas (molar ratio of nitrogen to the mixed feedstock was 1:3), a pressure of 0.05MPa, and a weight hourly space velocity (WHSV) of 2.0h⁻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. Its technical indicators are listed in Table 1.

[0102] Comparative Example 1

[0103] 0.28 g NaOH was dissolved in 280 g water, and 0.83 g aluminum nitrate was added. The mixture was stirred until dissolved, forming a transparent solution. Then, 29 g tetrabutylammonium bromide and 27 g 40% silica sol were added to this solution. The mixture was stirred at room temperature for 24 hours, transferred to a 100 ml reactor, and crystallized at 170 °C for 72 hours. After rapid cooling and centrifugation, the mixture was dried at 100 °C for 10 hours and calcined at 550 °C for 6 hours to obtain an ammonium-type molecular sieve. The obtained ammonium-type molecular sieve was then exchanged with a 0.1 mol / L ammonium chloride solution at a solid-liquid ratio of 1:50 at 80 °C for 4 hours. This process was repeated three times. After filtration, washing, and drying, the H-type catalyst DB-1 was obtained.

[0104] 5g of DB-1 was impregnated in 100ml of 0.1mol / L La(NO3)3 solution for 3 hours, then filtered, washed and dried, extruded into strips and crushed to 20-40 mesh. The resulting catalyst was denoted as DCat1.

[0105] The La2O3 content in catalyst DCat1 is 7.9%.

[0106] Molecular sieve DB-1 has a typical ZSM-11 molecular sieve structure and a specific surface area of ​​359 m². 2 / g, pore volume is 0.29cm 3 / g.

[0107] Scanning electron microscope images of DB-1 ( Figure 5 As can be seen, the molecular sieve has a columnar nanoribbon morphology with a length of 800-1200 nm, a width of 200-400 nm, and a thickness of 100-150 nm.

[0108] A fixed-bed reactor was used, loaded with 3g of shaped catalyst DCat1. Toluene and methanol were mixed at a molar ratio of 1:1, vaporized, and evenly dispersed at room temperature before entering the reactor. The reaction was carried out at a temperature of 480℃, with nitrogen as the carrier gas (molar ratio of nitrogen to the mixed feedstock was 1:3), a pressure of 0.05MPa, and a weight hourly space velocity (WHSV) of 2.0h⁻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. Its technical indicators are listed in Table 1.

[0109] Table 1

[0110]

Claims

1. A toluene and methanol alkylation catalyst, comprising a ZSM-11 molecular sieve and a metal oxide; the ZSM-11 molecular sieve has a morphology of a conical particle with nanorods orderly accumulated, the particle size of the conical particle is 500 nm to 2 μm, the radial size of the nanorods is 20 to 60 nm, and the bottom surface of the conical particle has a protrusion with a size of 100 to 300 nm; in the ZSM-11 molecular sieve, the conical particles with nanorods orderly accumulated are secondarily accumulated, and in the secondary accumulation, the conical particles are accumulated in a manner that the bottom surface faces outward and the vertex faces inward; and the metal oxide is at least one selected from metal oxides of Group IIA, Group IVA, Group VA, Group IIIB, Group IVB, Group VIB and Group VIII in the periodic table. A preparation method of the toluene and methanol alkylation catalyst, comprising: (1) mixing a first aluminum source, a first alkali source, a first template agent, a structure aid and water to obtain a solution A; mixing a first silicon source with the solution A to obtain an initial gel, and crystallizing the initial gel to obtain ZSM-11 molecular sieve seeds; (2) mixing a second aluminum source, a second alkali source, a second template agent, a second silicon source and water to obtain a solution B, mixing the solution B with the ZSM-11 molecular sieve seeds obtained in step (1), and crystallizing, drying and calcining the mixture to obtain a ZSM-11 molecular sieve; (3) loading a metal on the ZSM-11 molecular sieve obtained in step (2), and shaping to obtain the catalyst.

2. The catalyst according to claim 1, characterized in that, The ZSM-11 molecular sieve has a morphology of a conical particle with nanorods orderly accumulated, the particle size of the conical particle is 800 nm to 1.5 μm, the radial size of the nanorods is 30 to 50 nm, and the bottom surface of the conical particle has a protrusion with a size of 100 to 200 nm.

3. The catalyst of claim 1, wherein In the catalyst, the content of the metal oxide is 0.1% to 30% based on the mass of the ZSM-11 molecular sieve.

4. The catalyst of claim 3, wherein In the catalyst, the content of the metal oxide is 0.5% to 10% based on the mass of the ZSM-11 molecular sieve.

5. The catalyst of claim 1, wherein The metal in the metal oxide of Group IIA is at least one selected from Mg, Ca and Ba, the metal in the metal oxide of Group IVA is at least one selected from Sn and Pb, the metal in the metal oxide of Group VA is Bi, the metal in the metal oxide of Group IIIB is at least one selected from La and Ce, the metal in the metal oxide of Group IVB is at least one selected from Zr and Ti, the metal in the metal oxide of Group VIB is Mo, and the metal in the metal oxide of Group VIII is at least one selected from Fe, Co, Ni, Pt and Pd.

6. The catalyst of claim 1, wherein The metal in the metal oxide is at least one selected from La, Ce, Co, Mg and Ba.

7. The catalyst of claim 1, wherein The ZSM-11 molecular sieve has a hierarchical pore structure with micropores and mesopores, and the mesopore size is 10 to 50 nm.

8. The catalyst of claim 1, wherein The specific surface area of the ZSM-11 molecular sieve is 325-516 m 2 / g, and the pore volume is 0.29-0.59 cm 3 / g, and the mesopore volume is 0.30-0.52 cm 3 / g.

9. The catalyst of claim 8, wherein The ZSM-11 molecular sieve has a pore volume of 0.45 to 0.59 cm 3 / g. 10.A preparation method of the toluene and methanol alkylation catalyst according to any one of claims 1 to 9, comprising: (1) mixing a first aluminum source, a first alkali source, a first template agent, a structure aid and water to obtain a solution A; The first silicon source is mixed with solution A to obtain an initial gel, and the ZSM-11 molecular sieve seeds are obtained through crystallization; (2) The second aluminum source, the second alkali source, the second template agent, the second silicon source and water are mixed to obtain solution B, and solution B is mixed with the ZSM-11 molecular sieve seeds obtained in step (1), and the ZSM-11 molecular sieve is obtained through crystallization, drying and calcination. (3) The ZSM-11 molecular sieve obtained in step (2) is loaded with metal and shaped to obtain the catalyst.

11. The method of claim 10, wherein, The structure aid is selected from at least one of cetyltrimethylammonium bromide or polydiallyldimethylammonium chloride; the first template agent or the second template agent is each independently selected from at least one of tetrabutylammonium hydroxide, tetrabutylammonium bromide or 1,8-diammonium octane; the first silicon source or the second silicon source is each independently selected from at least one of tetraethyl orthosilicate, sodium silicate, fumed silica or silica sol; the first aluminum source or the second aluminum source is each independently selected from at least one of pseudo-boehmite, aluminum nitrate, sodium metaaluminate, aluminum sulfate or aluminum isopropoxide; and the first alkali source or the second alkali source is each independently selected from at least one of sodium hydroxide or potassium hydroxide.

12. The method of claim 10, wherein, In step (1), the molar ratio of the first aluminum source (calculated as Al2O3), the first silicon source (calculated as SiO2), the first alkali source (calculated as an oxide), the first template agent and water is as follows: (0.01-0.005):1:(0.005-0.02):(0.10-1.0):(80-200); and / or, in step (2), the molar ratio of the second aluminum source (calculated as Al2O3), the second silicon source (calculated as SiO2), the second alkali source (calculated as an oxide), the second template agent and water is as follows: (0.02-0.005):1:(0.005-0.02):(0.20-1.0):(100-200).

13. The preparation method according to claim 10, characterized in that, In step (1), the addition amount of the structure aid is 10%-70% of the mass of the first silicon source (calculated as SiO2); and / or, in step (2), the addition amount of the ZSM-11 molecular sieve seeds is 1%-10% of the mass of the second silicon source (calculated as SiO2).

14. The method of claim 10, wherein, In step (1), the crystallization conditions are as follows: the crystallization temperature is 140-220 ℃, and the crystallization time is 24-96 hours; and / or, in step (2), the crystallization is two-stage crystallization, and the crystallization conditions are as follows: the one-stage crystallization temperature is 30-60 ℃ lower than the crystallization temperature in step (1), the one-stage crystallization time is 12-60 hours; the two-stage crystallization temperature is 30-60 ℃ higher than the one-stage crystallization temperature, and the two-stage crystallization time is 12-60 hours.

15. The preparation method according to claim 14, characterized in that, In step (1), the crystallization conditions are as follows: the crystallization temperature is 150-180 ℃, and the crystallization time is 48-96 hours; and / or, in step (2), the one-stage crystallization time is 12-48 hours; and the two-stage crystallization time is 24-48 hours.

16. The method of claim 10, wherein, In step (2), the calcination conditions are as follows: the calcination temperature is 500-800 ℃, and the calcination time is 3-12 hours.

17. The method of claim 16, wherein, In step (2), the calcination conditions are as follows: the calcination temperature is 530-650 ℃, and the calcination time is 4-8 hours.

18. The method of claim 10, wherein, In step (3), the concentration of the metal source, as an oxide, is 0.01-1 mol / L.

19. The method of claim 10, wherein, In step (3), the amount of the metal added, as an oxide, is 3-60% based on the mass of the ZSM-11 molecular sieve.

20. The method of claim 19, wherein, In step (3), the amount of the metal added, as an oxide, is 5-40% based on the mass of the ZSM-11 molecular sieve.

21. Use of the catalyst of any one of claims 1-9 or the catalyst prepared by the method of any one of claims 10-20 in the alkylation of toluene with methanol to produce xylene.

22. The use according to claim 21, characterized in that, The reaction conditions of the reaction are as follows: the molar ratio of toluene to methanol is 0.1-10, the reaction temperature is 300-600 DEG C, the reaction pressure is 0-1.0 MPa, the weight space velocity of the toluene and methanol is 1-30 h -1 , and the carrier gas carrying the reaction raw materials into the catalyst bed is an inert gas.

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