Composite catalyst and method for directly preparing durene from synthesis gas

Abstract

The invention provides a composite catalyst and a method for directly preparing durene from synthesis gas. The composite catalyst comprises a metal-based catalyst, a chambering HZSM-5 molecular sieve and an HMCM-22 molecular sieve in a mass ratio of 1: (0.5-3.0): (0.05-0.5), wherein the metal-based catalyst comprises a metal oxide, and metal elements in the metal oxide comprise copper, zinc and zirconium in a molar ratio of 3: (1.0-2.0): (0.1-6.0). The inactivation rate of the catalyst can be effectively slowed down by increasing the proportion of ZrO2 in the copper-based catalyst, the embodied medium catalytic activity is just matched with the treatment capacity of a molecular sieve, and less aliphatic hydrocarbon selectivity and higher durene selectivity are obtained; through design and modification of the composite catalyst, the problems of easy deactivation and activity matching of the catalyst are solved, and high-selectivity production of durene is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of durene, and in particular to a method for directly preparing durene from a composite catalyst and synthesis gas. Background Art

[0002] Copper-zinc-aluminum catalysts are highly active and well-established methanol synthesis catalysts. However, operating temperatures exceeding 320°C can lead to excessive methanation and irreversible sintering deactivation. The aromatization activity temperature of HZSM-5 zeolite used with copper-zinc-aluminum catalysts must exceed 350°C, limiting their industrial application in the one-step aromatics production process. Furthermore, HZSM-5 zeolite continuously deactivates due to carbon deposition during the reaction, resulting in a decrease in aromatization capacity and, consequently, a reduction in product selectivity.

[0003] CN110075908A discloses a catalyst for the one-step synthesis of aromatics from syngas and its preparation method. The catalyst comprises a silica-alumina molecular sieve and a composite metal oxide. The surface of the silica-alumina molecular sieve is treated with silica deposition and metal modification, with the modifying metal being selected from at least one of Zn, Ga, Ag, Mo, Cu, Fe, Ni, Co, Mn, La, Pr, and Nd. The composite metal oxide is at least one of cerium oxide-zirconium oxide, zinc oxide-zirconium oxide, or zinc oxide-chromium oxide. The catalyst is prepared by first depositing silica and metal modification on the surface of the silica-alumina molecular sieve, then uniformly mixing the surface with the composite metal oxide and granulating the mixture to produce the catalyst. However, this method has a low raw material conversion rate, reaching a maximum of only 40%.

[0004] CN108079913A discloses a two-stage fluidized bed reactor and method for producing aromatics from syngas. This technology prepares the methanol synthesis catalyst and aromatization catalyst into fluidized catalysts with larger and smaller particle sizes, respectively. The lower region of the two-stage reactor is a low-temperature syngas-to-methanol region, and the upper region is a high-temperature methanol aromatization region. The heat exchanger in the lower region is connected to the heat exchanger in the upper region, so that cooling water is heat-exchanged in the lower region to become saturated steam, and the temperature of the lower region is controlled; the saturated steam is heat-exchanged in the upper region to become superheated steam, and the temperature of the upper region is controlled. However, this technology uses two fluidized bed reactors connected in series. Due to the different densities of the different catalysts, the reaction process is prone to backmixing, which reduces the reaction efficiency of the two-stage reaction. Summary of the Invention

[0005] To solve the above technical problems, the purpose of the present invention is to provide a composite catalyst and a method for directly preparing durene from synthesis gas, thereby improving the heat resistance of the catalyst and the selectivity of durene for directly preparing durene from synthesis gas.

[0006] To achieve the above object, the present invention provides a composite catalyst comprising a metal-based catalyst, an expanded pore HZSM-5 molecular sieve, and an HMCM-22 molecular sieve in a mass ratio of 1:(0.5-3.0):(0.05-0.5);

[0007] The metal-based catalyst comprises metal oxide, and the metal elements in the metal oxide comprise copper, zinc and zirconium in a molar ratio of 3: (1.0-2.0): (0.1-6.0).

[0008] According to a specific embodiment of the present invention, preferably, the metal elements in the metal oxide further include aluminum, and the molar ratio of copper, zinc, zirconium and aluminum is 3: (1.0-2.0): (0.1-6.0): (0.3-6.0).

[0009] The composite catalyst of the present invention is composed of a metal-based catalyst containing copper, zinc, and zirconium, an expanded-pore HZSM-5 molecular sieve, and HMCM-22 mixed in a specific proportion. Zr and, preferably, Al are structural additives. By regulating the ratio of Zr to Al in the structural additives and the calcination conditions, the present invention obtains a metal-based catalyst with a well-defined pore structure, a tetragonal ZrO2 structure, uniformly dispersed Cu particles, and a well-defined pore structure. Due to the structural characteristics of ZrO2, the reducing properties of CuO are weakened, slowing the migration and aggregation of Cu particles in a reducing atmosphere and ensuring the excellent thermal stability of the metal-based catalyst.

[0010] In this invention, the expanded pore HZSM-5 molecular sieve has a high number of mesopores, which enhances molecular diffusion within the pores and reduces the probability of soft carbon accumulation during the catalytic reaction. Furthermore, by adding an appropriate proportion of HMCM-22 molecular sieve, the present invention improves the selectivity of durene in the synthesis gas reaction; if a large amount of doping is added, the selectivity of pentamethylbenzene is also increased. The present invention combines a metal-based catalyst, expanded pore HZSM-5 molecular sieve, and HMCM-22 molecular sieve to significantly increase the reaction rate of direct synthesis gas to durene.

[0011] According to a specific embodiment of the present invention, preferably, the specific surface area of ​​the metal-based catalyst is 45-120m 2 / g, pore volume of 0.08-0.23cm 3 / g.

[0012] According to a specific embodiment of the present invention, preferably, the pore volume of the expanded pore HZSM-5 molecular sieve is 0.47-0.65 cm 3 / g.

[0013] According to a specific embodiment of the present invention, preferably, the metal-based catalyst is prepared by a co-precipitation method, and the preparation method of the metal-based catalyst comprises the following steps:

[0014] A metal mixed solution containing the metal element is mixed with an alkaline solution, and co-precipitated at a pH value of 6.5-8 to obtain a precipitate, which is then calcined at 500-600° C. for 4-8 hours to obtain the metal-based catalyst.

[0015] According to a specific embodiment of the present invention, preferably, in the preparation of the metal-based catalyst, the co-precipitation temperature is 50-70°C.

[0016] According to a specific embodiment of the present invention, preferably, the method for preparing the metal-based catalyst comprises the following steps:

[0017] Mix water-soluble copper salt, zinc salt, zirconium salt, aluminum salt and water in a molar ratio of 3: (1.0-2.0): (0.01-6.0): (0.01-1.0): (60-600) to prepare solution A;

[0018] Sodium carbonate, sodium hydroxide and water are mixed in a molar ratio of 1:(0.5-2.0):(100-220) to prepare solution B;

[0019] The solution A and the solution B are added to water simultaneously, and the pH value of the solution is maintained at 6.5-8.0. During the process, stirring is maintained and the water bath is kept at 50-70° C. to perform precipitation. After the precipitation is completed, the product is washed to obtain the product, and then dried and calcined in sequence to obtain the metal-based catalyst.

[0020] According to a specific embodiment of the present invention, preferably, the method for preparing the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0021] Mixing a first silicon source, a first aluminum source, a template, and a pore-enlarging agent in a molar ratio of 1:(0.07-0.17):(0.1-1):(0.01-0.2) in an alkaline aqueous solution to obtain a first gel; the pore-enlarging agent is polyethylene glycol;

[0022] The first gel is crystallized and calcined, and the ammonium salt of the calcined product is ion-exchanged and calcined again to obtain the pore-enlarged HZSM-5 molecular sieve.

[0023] The present invention adds polyethylene glycol as an auxiliary agent during the preparation of the pore-enlarged HZSM-5 molecular sieve, thereby increasing the number of mesopores of the catalyst, enhancing the molecular diffusion in the pores, and reducing the probability of accumulation of soft carbon deposits.

[0024] According to a specific embodiment of the present invention, preferably, in the preparation of the pore-expanded HZSM-5 molecular sieve, the first silicon source is ethyl orthosilicate.

[0025] According to a specific embodiment of the present invention, preferably, in the preparation of the pore-expanded HZSM-5 molecular sieve, the first aluminum source is aluminum nitrate or sodium metaaluminate.

[0026] According to a specific embodiment of the present invention, preferably, in the preparation of the pore-expanded HZSM-5 molecular sieve, the template agent is tetrapropylammonium hydroxide and / or N,N,N-trimethyl-1-adamantylammonium hydroxide.

[0027] According to a specific embodiment of the present invention, preferably, in the preparation method of the pore-expanded HZSM-5 molecular sieve, the crystallization temperature is 120-170° C., and the crystallization time is 24-72 h.

[0028] According to a specific embodiment of the present invention, preferably, in the preparation of the pore-expanded HZSM-5 molecular sieve, the temperature of the two calcinations is 500-600° C., and the time is 2-4 h.

[0029] According to a specific embodiment of the present invention, preferably, in the preparation of the pore-expanded HZSM-5 molecular sieve, the reaction temperature of the ion exchange is 80-95° C., and the reaction time is 3-9 h.

[0030] According to a specific embodiment of the present invention, preferably, the method for preparing the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0031] TEOS, tetrapropylammonium hydroxide, polyethylene glycol, and water were mixed in a molar ratio of 1:(0.1-1):(0.01-0.2):(5.0-20.0) to prepare a solution C;

[0032] Aluminum nitrate, sodium hydroxide, and deionized water were mixed in a molar ratio of 1:(1.0-3.0):(10.0-100.0) to prepare solution D;

[0033] Solution D was added to solution C, and the resulting gel was subjected to static crystallization, followed by centrifugation, washing, drying, and calcination to obtain a Na-ZSM-5 molecular sieve catalyst;

[0034] The Na-ZSM-5 molecular sieve is placed in an ammonium nitrate solution for ion exchange, and then centrifuged, washed, dried, and calcined to obtain the pore-enlarged HZSM-5 molecular sieve.

[0035] According to a specific embodiment of the present invention, preferably, when solution D is added to solution C, the mass ratio of solution C to solution D is 4-17:1.

[0036] According to a specific embodiment of the present invention, preferably, the preparation method of the HMCM-22 molecular sieve comprises the following steps:

[0037] Mixing a second silicon source, a second aluminum source, and hexamethyleneimine in a molar ratio of 1:(0.01-0.2):(0.02-0.5) in an alkaline aqueous solution to obtain a second gel;

[0038] The second gel is crystallized and calcined, and the calcined product is ion-exchanged with an ammonium salt and calcined again to obtain the HMCM-22 molecular sieve.

[0039] According to a specific embodiment of the present invention, preferably, in the preparation of HMCM-22 molecular sieve, the crystallization temperature is 120-170° C., and the crystallization time is 60-84 h.

[0040] According to a specific embodiment of the present invention, preferably, in the preparation of HMCM-22 molecular sieve, the temperature of the two calcinations is 500-600° C. and the time is 2-4 h.

[0041] According to a specific embodiment of the present invention, preferably, in the preparation of HMCM-22 molecular sieve, the reaction temperature of the ion exchange is 70-90° C., and the reaction time is 3-9 h.

[0042] According to a specific embodiment of the present invention, preferably, the preparation method of the HMCM-22 molecular sieve comprises the following steps:

[0043] Sodium metaaluminate, sodium hydroxide, and water were mixed in a molar ratio of 1:(0.01-1.0):(10.0-200.0) to prepare solution E;

[0044] Solution E was added dropwise to the silica sol, stirred thoroughly and cooled, and then hexamethyleneimine was added. The molar ratio of silica sol to hexamethyleneimine was 1:(0.2-0.5). The resulting gel was subjected to static crystallization, followed by centrifugation, washing, drying, and calcination to obtain a Na-MCM-22 molecular sieve catalyst.

[0045] The Na-MCM-22 molecular sieve is placed in an ammonium nitrate solution for ion exchange, and then centrifuged, washed, dried, and calcined to obtain the HMCM-22 molecular sieve.

[0046] According to a specific embodiment of the present invention, preferably, when the solution E is added dropwise to the silica sol, the mass ratio of the solution E to the silica sol is 0.05-0.9:1.

[0047] According to a specific embodiment of the present invention, preferably, the particle sizes of the metal-based catalyst, the expanded pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve are 20-200 meshes, respectively.

[0048] According to a specific embodiment of the present invention, preferably, the composite catalyst is prepared by the following steps:

[0049] S1. Preparation of metal-based catalysts:

[0050] Copper nitrate hydrate, zinc nitrate hydrate, zirconium nitrate hydrate, aluminum nitrate hydrate, and deionized water were mixed in a molar ratio of 3: (1.0-2.0): (0-6.0): (0-1.0): (60-600) to prepare solution A, and the mixture was placed in a (50-80)°C water bath and stirred until the solution became clear;

[0051] Sodium carbonate, sodium hydroxide and deionized water are mixed in a molar ratio of 1: (0.5-2.0): (20-100) to prepare solution B;

[0052] Solution A and solution B were added to deionized water simultaneously using a peristaltic pump, and the pH value of the solution was maintained at 6.5-8.0. Stirring and a 50-70°C water bath were maintained during the process. After the addition was completed, aging and stirring were continued for 0.5-1h, and the filtrate was filtered and washed with deionized water until the pH of the filtrate was ≤7. The resulting filter cake was dried in an oven at 100-120°C for 12-24h, and then placed in a muffle furnace for calcination at 350-550°C for 2-4h to obtain the metal-based catalyst.

[0053] S2. Preparation of pore-enlarged HZSM-5 molecular sieve:

[0054] TEOS, tetrapropylammonium hydroxide, polyethylene glycol, and deionized water were mixed in a molar ratio of 1:(0.1-1):(0.01-0.2):(5.0-20.0) to prepare a solution C;

[0055] Aluminum nitrate, sodium hydroxide, and deionized water were mixed in a molar ratio of 1:(1.0-3.0):(10-100) to prepare a solution D;

[0056] Solution D was slowly added to solution C, and the resulting gel was transferred to a hydrothermal autoclave reactor and placed in an oven at 120-170°C for static crystallization for 24-72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was then washed with deionized water to a pH of ≤7. The white solid was then dried in an oven at 100-120°C for 12-24 hours, and then calcined in a muffle furnace at 500-600°C for 2-4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0057] The Na-ZSM-5 molecular sieve is placed in a 1M NH4Cl solution with a mass of 5-15 times, placed in an 80°C water bath for 3 hours, and the operation is repeated three times; a white solid is separated using a high-speed centrifuge, and washed with deionized water until the pH is ≤ 7; the white solid is then dried in an oven at 100-120°C for 12-24 hours, and then placed in a muffle furnace for calcination at 500-600°C for 2-4 hours to obtain the pore-expanded HZSM-5 molecular sieve catalyst;

[0058] Preparation of S3, HMCM-22 molecular sieve:

[0059] Sodium metaaluminate, sodium hydroxide, and deionized water were mixed in a molar ratio of 1:(0.01-1.0):(10.0-200.0) to prepare solution E;

[0060] Solution E was gradually added dropwise to the silica sol. After thorough stirring and cooling, hexamethyleneimine was added in a molar ratio of silica sol to hexamethyleneimine of 1:(0.2-0.5). The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 120-170° C. for static crystallization for 60-84 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was then washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 100-120° C. for 12-24 hours and then calcined in a muffle furnace at 500-600° C. for 2-4 hours to obtain a Na-MCM-22 molecular sieve catalyst.

[0061] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 100-120°C and dried for 12-24 hours, and then placed in a muffle furnace at 500-600°C and calcined for 2-4 hours to obtain the HMCM-22 molecular sieve catalyst.

[0062] S4. Composite formation catalyst:

[0063] The metal-based catalyst prepared in the above step, the expanded pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve are physically mixed in a mass ratio of 1:(0.5-3.0):(0.05-0.5) to obtain a composite catalyst. It should be noted that the mixing in S4 can be achieved by conventional mechanical or physical mixing methods that can achieve uniform mixing of the two.

[0064] The present invention also provides a method for directly preparing durene from synthesis gas, which adopts the composite catalyst for catalysis.

[0065] According to a specific embodiment of the present invention, preferably, the method for directly preparing durene from synthesis gas comprises the following steps:

[0066] reducing the composite catalyst using hydrogen;

[0067] At 280-360℃ and 2-6MPa, the synthesis gas is heated at 450-3600mL·h -1 ·gcat -1The space velocity is sufficient to contact with the reduced composite catalyst for reaction, and the reaction product is subjected to gas-liquid separation to obtain tetramethylbenzene in the liquid phase product.

[0068] In the above method for directly preparing durene from synthesis gas, preferably, the reaction conditions are preferably 300-340° C. and 3-5 MPa.

[0069] During the reaction, synthesis gas first generates a methanol intermediate on the surface of the metal-based catalyst. This intermediate diffuses onto the surfaces of the expanded-pore HZSM-5 and HMCM-22 molecular sieves, where methanol dehydration, olefination, aromatization, and aromatic alkylation reactions occur at the acidic sites of the molecular sieves, resulting in highly selective durene production. The reaction products are condensed and subjected to gas-liquid separation to produce a gaseous product containing nitrogen, carbon monoxide, carbon dioxide, and C1-C4 alkanes, and a liquid product containing aliphatic hydrocarbons, aromatic hydrocarbons, dimethyl ether, methanol, and water.

[0070] In the above method for directly preparing durene from synthesis gas, preferably, the volume ratio of carbon monoxide to hydrogen in the synthesis gas is 1:1-3, more preferably 1:2.

[0071] In the above method for directly preparing durene from synthesis gas, preferably, the volume content of carbon monoxide in the synthesis gas is 31%, and the volume content of hydrogen is 62%.

[0072] In the above-mentioned method for directly preparing durene from synthesis gas, preferably, the reduction process of the composite catalyst is carried out using a mixed gas with a hydrogen volume content of 5%; the reduction conditions are: reduction at 180-280° C. for 2-8 hours.

[0073] According to a specific embodiment of the present invention, preferably, the method for directly producing durene from synthesis gas comprises the following steps: loading the composite catalyst into the constant temperature section of a fixed bed reactor, verifying the overall airtightness, introducing a mixture of nitrogen and hydrogen, and heating the reactor from room temperature to the reduction temperature under a reducing atmosphere, wherein the catalyst is partially reduced during this process; after the reduction is completed, introducing synthesis gas containing carbon monoxide, hydrogen, and nitrogen, back-pressurizing the reactor to the desired operating pressure, and then heating the reactor to the desired operating temperature. The details are as follows:

[0074] The composite catalyst is installed on the catalyst bed with a mesh size of 20-200;

[0075] After the airtightness test, the composite catalyst is reduced using a mixed gas (95% N2, 5% H2) at atmospheric pressure and 180-280°C for 2-8 hours. After the reduction is complete, synthesis gas (31% CO, 62% H2, 7% N2) is introduced, the back pressure is slowly increased to 2-6 MPa, and the temperature is raised to 280-360°C. The synthesis gas space velocity is controlled at (450-3600) mL·h -1 ·gcat-1 ;

[0076] The reaction product is subjected to gas-liquid separation to obtain a liquid phase product containing the target product heavy aromatics.

[0077] It should be noted that gas-liquid separation can be achieved by conventional methods such as gravity sedimentation, inertial collision, centrifugal separation, electrostatic attraction, and diffusion.

[0078] The synthesis gas fully contacts the composite catalyst, and CO and H2 undergo a methanol synthesis reaction on the surface of the copper-zinc-zirconium-aluminum catalyst. Methanol then diffuses through the airflow onto the surfaces of the expanded-pore HZSM-5 and HMCM-22 molecular sieves, undergoing reactions such as methanol dehydration, olefination, aromatization, and alkylation. The final reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons, and water, with durene as the primary product.

[0079] The method for directly producing durene from syngas provided by the present invention achieves a one-step catalytic conversion of syngas into durene in a single reactor. The optimized metal-based catalyst activity is better matched with the aromatization activity of the bimolecular sieve. In some specific embodiments, the CO conversion rate is 65.42%, and the overall durene selectivity is 31.65%, which is significantly superior. Furthermore, the composite catalyst shows no significant deactivation during the 100-hour reaction. This composite catalyst has excellent industrial application prospects.

[0080] The technical solution provided by the present invention has the following beneficial effects:

[0081] In the process of directly producing duren from synthesis gas, the use of highly active copper-based catalysts is prone to irreversible sintering of copper particles. The present invention effectively slows down the catalyst deactivation rate by increasing the ZrO2 ratio in the copper-based catalyst. The moderate catalytic activity exhibited is just matched with the processing capacity of the molecular sieve, resulting in less aliphatic hydrocarbon selectivity and higher duren selectivity. The expanded pore HZSM-5 molecular sieve is conducive to the diffusion of products within the pores, reducing the accumulation of soft carbon deposits that are prone to occur when producing heavy aromatics. The mixed filling of HMCM-22 molecular sieves greatly promotes the alkylation process of aromatics, and an appropriate HMCM-22 filling ratio can further increase the overall selectivity of duren. The present invention solves both the problem of easy catalyst deactivation and the problem of activity matching through the design and modification of the composite catalyst, achieving highly selective production of duren. The composite catalyst has high application value. DETAILED DESCRIPTION

[0082] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0083] Example 1

[0084] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0085] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0086] 36.24 g of copper nitrate, 22.31 g of zinc nitrate, 10.733 g of zirconium nitrate and 300 mL of deionized water were mixed to prepare solution A, which was placed in a 70°C water bath and stirred thoroughly until the solution became clear; 17.6 g of sodium hydroxide, 23.32 g of sodium carbonate and 300 mL of deionized water were mixed to prepare solution B, and solution A and solution B were gradually added to 100 ml of deionized water using a peristaltic pump simultaneously, maintaining the solution pH = 8, while stirring and maintaining a 70°C water bath; after the precipitation process was completed, the solution was aged and stirred for 0.5 h, and filtered and washed until the filtrate pH was <7; the filter cake was placed in an oven and dried at 110°C for 12 h, and then placed in a muffle furnace and calcined at 550°C for 4 h to obtain a metal-based catalyst.

[0087] The metal-based catalyst has a black solid appearance and a specific surface area of ​​75.14 m 2 / g, pore volume is 0.17cm 3 / g, and the average grain size is 9.6nm.

[0088] S2. The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0089] 19.50 g of tetraethyl orthosilicate, 14.28 g of tetrapropylammonium hydroxide, 2 g of polyethylene glycol and 10 g of deionized water were mixed to prepare solution C, which was placed in an 80° C. water bath and stirred thoroughly for 24 h. 1.04 g of aluminum nitrate, 0.55 g of NaOH and 7.5 mL of deionized water were mixed to prepare solution D. Solution D was gradually added to solution C, with a mass ratio of solution C to solution D of 5.68. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170° C. for static crystallization for 48 h. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110° C. for 12 h and then calcined in a muffle furnace at 550° C. for 4 h to obtain a Na-ZSM-5 molecular sieve catalyst.

[0090] 5 g of Na-ZSM-5 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; then a white solid was separated using a high-speed centrifuge and washed with deionized water until the pH was neutral. The white solid was then placed in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain a pore-expanded HZSM-5 molecular sieve catalyst.

[0091] The expanded pore HZSM-5 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.57 cm 3 / g, with a specific surface area of ​​369m 2 / g, and the average pore diameter is 5.64nm.

[0092] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0093] Solution E was prepared by mixing 2.05 g of sodium metaaluminate, 0.70 g of sodium hydroxide, and 80 mL of deionized water. Solution E was gradually added dropwise to 80 mL of silica gel with stirring. After the white gel cooled to room temperature, 10 mL of hexamethyleneimine was slowly added dropwise with stirring for 15 minutes. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid. The solid was washed with deionized water until the pH was neutral, then dried in an oven at 110°C for 12 hours and calcined in a muffle furnace at 550°C for 4 hours to obtain the Na-MCM-22 molecular sieve catalyst. The molar ratio of the silicon source to the aluminum source was 1:0.05.

[0094] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0095] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.26 cm 3 / g, with a specific surface area of ​​370m 2 / g.

[0096] S4. The catalyst is compounded by the following steps:

[0097] The copper-zinc-zirconium-aluminum catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve were mixed in a mass ratio of 6:6:1 to obtain a composite catalyst.

[0098] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0099] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0100] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0101] Example 2

[0102] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0103] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0104] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 21.47g of zirconium nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 17.6g of sodium hydroxide, 23.32g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is <7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0105] The metal-based catalyst has a black solid appearance and a specific surface area of ​​55.98 m 2 / g, pore volume is 0.14cm 3 / g, and the average grain size is 10.77nm.

[0106] S2. The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0107] 19.50 g of tetraethyl orthosilicate, 14.28 g of tetrapropylammonium hydroxide, 1 g of polyethylene glycol and 10 g of deionized water were mixed to prepare solution C, which was placed in an 80°C water bath and stirred thoroughly for 24 hours. 1.04 g of aluminum nitrate, 0.55 g of NaOH and 7.5 mL of deionized water were mixed to prepare solution D. Solution D was gradually added to solution C with a mass ratio of solution C to solution D of 4.93. The resulting gel was transferred to a hydrothermal autoclave reactor and placed in an oven at 170°C for static crystallization for 48 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0108] 5g of Na-ZSM-5 molecular sieve was placed in 50ml of 1M NH4Cl solution and placed in an 80°C water bath for 3 hours. This process was repeated three times. A white solid was separated using a high-speed centrifuge and washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110°C for 12 hours and calcined in a muffle furnace at 550°C for 4 hours to obtain a pore-enlarged HZSM-5 molecular sieve catalyst.

[0109] The expanded pore HZSM-5 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.57 cm 3 / g, with a specific surface area of ​​369m 2 / g, and the average pore diameter is 5.64nm.

[0110] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0111] Solution E was prepared by mixing 2.05 g of sodium metaaluminate, 0.90 g of sodium hydroxide, and 89.6 mL of deionized water. Solution E was gradually added dropwise to 90 mL of silica gel with stirring. After the white gel cooled to room temperature, 20 mL of hexamethyleneimine was slowly added dropwise with stirring for 15 minutes. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid. The solid was washed with deionized water until the pH was neutral, then dried in an oven at 110°C for 12 hours and calcined in a muffle furnace at 550°C for 4 hours to obtain the Na-MCM-22 molecular sieve catalyst. The molar ratio of the silicon source to the aluminum source was 1:0.046.

[0112] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0113] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.29 cm 3 / g, specific surface area of ​​359m 2 / g.

[0114] S4. The catalyst is compounded by the following steps:

[0115] The copper-zinc-zirconium-aluminum catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve were mixed in a mass ratio of 1:1.5:0.5 to obtain a composite catalyst.

[0116] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0117] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0118] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0119] Example 3

[0120] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0121] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0122] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 42.932g of zirconium nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 25.34g of sodium hydroxide, 33.576g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is less than 7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0123] The metal-based catalyst has a black solid appearance and a specific surface area of ​​32.45 m 2 / g, pore volume is 0.10cm 3 / g, and the average grain size is 14.03nm.

[0124] S2. The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0125] 19.50 g of tetraethyl orthosilicate, 14.28 g of tetrapropylammonium hydroxide, 2 g of polyethylene glycol and 10 g of deionized water were mixed to prepare solution C, which was placed in an 80°C water bath and stirred thoroughly for 24 hours. 1.04 g of aluminum nitrate, 0.55 g of NaOH and 7.5 mL of deionized water were mixed to prepare solution D. Solution D was gradually added to solution C with a mass ratio of solution C to solution D of 4.93. The resulting gel was transferred to a hydrothermal autoclave reactor and placed in an oven at 170°C for static crystallization for 48 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0126] 5 g of Na-ZSM-5 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours, and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain a pore-expanded HZSM-5 molecular sieve catalyst.

[0127] The expanded pore HZSM-5 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.57 cm 3 / g, with a specific surface area of ​​369m 2 / g, and the average pore diameter is 5.64nm.

[0128] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0129] Solution E was prepared by mixing 2.05 g of sodium metaaluminate, 0.45 g of sodium hydroxide, and 44 mL of deionized water. Solution E was gradually added dropwise to 78.5 mL of silica gel with stirring. After the white gel cooled to room temperature, 10.7 mL of hexamethyleneimine was slowly added dropwise with stirring for 15 minutes. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid. The solid was washed with deionized water until the pH was neutral, then dried in an oven at 110°C for 12 hours and calcined in a muffle furnace at 550°C for 4 hours to obtain the Na-MCM-22 molecular sieve catalyst. The molar ratio of the silicon source to the aluminum source was 1:0.053.

[0130] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0131] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.26 cm 3 / g, with a specific surface area of ​​370m 2 / g.

[0132] S4. The catalyst is compounded by the following steps:

[0133] The copper-zinc-zirconium-aluminum catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve were mixed in a mass ratio of 1:0.5:0.3 to obtain a composite catalyst.

[0134] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0135] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1, maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0136] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0137] Example 4

[0138] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0139] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0140] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 21.47g of zirconium nitrate, 4.69g of aluminum nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 21.12g of sodium hydroxide, 27.98g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is less than 7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0141] The metal-based catalyst has a black solid appearance and a specific surface area of ​​84.62 m 2 / g, pore volume is 0.24cm 3 / g, and the average grain size is 8.62nm.

[0142] The preparation method of S2, HZSM-5 molecular sieve comprises the following steps:

[0143] 21.80 g of tetraethyl orthosilicate, 14.28 g of tetrapropylammonium hydroxide, 2.8 g of polyethylene glycol and 12 g of deionized water were mixed to prepare solution C, which was placed in an 80°C water bath and stirred thoroughly for 24 hours. 0.52 g of aluminum nitrate, 0.25 g of NaOH and 3.5 mL of deionized water were mixed to prepare solution D. Solution D was gradually added to solution C with a mass ratio of solution C to solution D of 11.9. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 48 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0144] 5 g of Na-ZSM-5 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours, and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain an HZSM-5 molecular sieve catalyst.

[0145] The HZSM-5 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.42 cm 3 / g, specific surface area of ​​390m 2 / g.

[0146] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0147] Solution E was prepared by mixing 2.05 g of sodium metaaluminate, 0.70 g of sodium hydroxide, and 20 mL of deionized water. Solution E was gradually added dropwise to 62.7 mL of silica gel with stirring. After the white gel cooled to room temperature, 17 mL of hexamethyleneimine was slowly added dropwise with stirring for 15 minutes. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid. The solid was washed with deionized water to a neutral pH, then dried in an oven at 110°C for 12 hours and calcined in a muffle furnace at 550°C for 4 hours to obtain the Na-MCM-22 molecular sieve catalyst. The molar ratio of the silicon source to the aluminum source was 1:0.07.

[0148] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0149] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.27 cm 3 / g, specific surface area of ​​389m 2 / g.

[0150] S4. The catalyst is compounded by the following steps:

[0151] The copper-zinc-zirconium-aluminum catalyst, HZSM-5 molecular sieve, and HMCM-22 molecular sieve were mixed in a mass ratio of 1:3:0.1 to obtain a composite catalyst.

[0152] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0153] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0154] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0155] Example 5

[0156] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0157] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0158] Solution A was prepared by mixing 36.24g of copper nitrate, 22.31g of zinc nitrate, 5.37g of zirconium nitrate, 9.38g of aluminum nitrate, and 300mL of deionized water. The mixture was placed in a 70°C water bath and stirred thoroughly until the solution was clear. Solution B was prepared by mixing 21.12g of sodium hydroxide, 27.98g of sodium carbonate, and 300mL of deionized water. Solution A and Solution B were gradually added to 100mL of deionized water using a peristaltic pump, maintaining the solution pH at 8 while stirring and maintaining a 70°C water bath. After the precipitation process, the mixture was aged and stirred for 0.5h, then filtered and washed until the filtrate pH was <7. The filter cake was dried in an oven at 110°C for 12h and then calcined in a muffle furnace at 550°C for 4h to obtain the metal-based catalyst.

[0159] The metal-based catalyst has a black solid appearance and a specific surface area of ​​98.81 m 2 / g, pore volume is 0.23cm 3 / g, and the average grain size is 6.32nm.

[0160] S2. The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0161] 24.80 g of tetraethyl orthosilicate, 17.37 g of tetrapropylammonium hydroxide, 3.5 g of polyethylene glycol and 15 g of deionized water were mixed to prepare solution C, which was placed in an 80°C water bath and stirred thoroughly for 24 hours; 0.52 g of aluminum nitrate, 0.25 g of NaOH and 3.5 mL of deionized water were mixed to prepare solution D; solution D was gradually added to solution C with a mass ratio of solution C to solution D of 14.2. The obtained gel was transferred to a hydrothermal autoclave reactor and placed in an oven at 170°C for static crystallization for 48 hours; after cooling, the obtained product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0162] 5 g of Na-ZSM-5 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours, and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain a pore-expanded HZSM-5 molecular sieve catalyst.

[0163] The expanded pore HZSM-5 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.57 cm 3 / g, with a specific surface area of ​​369m 2 / g, and the average pore diameter is 5.64nm.

[0164] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0165] Solution E was prepared by mixing 2.05 g of sodium metaaluminate, 0.20 g of sodium hydroxide, and 10 mL of deionized water. Solution E was gradually added dropwise to 50.62 mL of silica gel with stirring. After the white gel cooled to room temperature, 17.2 mL of hexamethyleneimine was slowly added dropwise with stirring for 15 minutes. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid. The solid was washed with deionized water until the pH was neutral, then dried in an oven at 110°C for 12 hours and calcined in a muffle furnace at 550°C for 4 hours to obtain the Na-MCM-22 molecular sieve catalyst. The molar ratio of the silicon source to the aluminum source was 1:0.08.

[0166] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0167] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.27 cm 3 / g, specific surface area of ​​376m 2 / g.

[0168] S4. The catalyst is compounded by the following steps:

[0169] The copper-zinc-zirconium-aluminum catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve were mixed in a mass ratio of 1:2:0.4 to obtain a composite catalyst.

[0170] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0171] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1, maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0172] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0173] Example 6

[0174] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0175] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0176] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 21.47g of zirconium nitrate, 4.69g of aluminum nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 21.12g of sodium hydroxide, 27.98g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is less than 7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0177] The metal-based catalyst has a black solid appearance and a specific surface area of ​​84.62 m 2 / g, pore volume is 0.24cm 3 / g, and the average grain size is 8.62nm.

[0178] S2. The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0179] 27.30 g of tetraethyl orthosilicate, 18.48 g of tetrapropylammonium hydroxide, 3.8 g of polyethylene glycol and 18 g of deionized water were mixed to prepare solution C, which was placed in an 80°C water bath and stirred thoroughly for 24 hours. 0.48 g of aluminum nitrate, 0.30 g of NaOH and 3.2 mL of deionized water were mixed to prepare solution D. Solution D was gradually added to solution C with a mass ratio of solution C to solution D of 16.98. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 48 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0180] 5 g of Na-ZSM-5 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours, and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain a pore-expanded HZSM-5 molecular sieve catalyst.

[0181] The expanded pore HZSM-5 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.57 cm 3 / g, with a specific surface area of ​​369m 2 / g, and the average pore diameter is 5.64nm.

[0182] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0183] Solution E was prepared by mixing 2.25 g of sodium metaaluminate, 0.20 g of sodium hydroxide, and 18 mL of deionized water. Solution E was gradually added dropwise to 169 mL of silica gel with stirring. After the white gel cooled to room temperature, 34.5 mL of hexamethyleneimine was slowly added dropwise with stirring for 15 minutes. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid. The solid was washed with deionized water until the pH was neutral, then dried in an oven at 110°C for 12 hours and calcined in a muffle furnace at 550°C for 4 hours to obtain the Na-MCM-22 molecular sieve catalyst. The molar ratio of the silicon source to the aluminum source was 1:0.029.

[0184] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0185] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.23 cm 3 / g, specific surface area of ​​358m 2 / g.

[0186] S4. The catalyst is compounded by the following steps:

[0187] The copper-zinc-zirconium-aluminum catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve were mixed in a mass ratio of 1:2.5:0.5 to obtain a composite catalyst.

[0188] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0189] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0190] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0191] Example 7

[0192] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0193] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0194] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 21.47g of zirconium nitrate, 4.69g of aluminum nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 21.12g of sodium hydroxide, 27.98g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is less than 7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0195] The metal-based catalyst has a black solid appearance and a specific surface area of ​​84.62 m 2 / g, pore volume is 0.24cm 3 / g, and the average grain size is 8.62nm.

[0196] S2. The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0197] 19.50 g of tetraethyl orthosilicate, 14.28 g of tetrapropylammonium hydroxide, 2 g of polyethylene glycol and 10 g of deionized water were mixed to prepare solution C, which was placed in an 80°C water bath and stirred thoroughly for 24 hours. 1.04 g of aluminum nitrate, 0.55 g of NaOH and 7.5 mL of deionized water were mixed to prepare solution D. Solution D was gradually added to solution C with a mass ratio of solution C to solution D of 5.03. The resulting gel was transferred to a hydrothermal autoclave reactor and placed in an oven at 170°C for static crystallization for 48 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0198] 5g of Na-ZSM-5 molecular sieve was placed in 50ml of 1M NH4Cl solution, placed in an 80℃ water bath for 3h, and repeated three times. A white solid was separated using a high-speed centrifuge and washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110℃ for 12h and then calcined in a muffle furnace at 550℃ for 4h to obtain the expanded pore HZSM-5 molecular sieve catalyst. The catalyst appears as a white powder with a pore volume of 0.57cm 3 / g, with a specific surface area of ​​369m 2 / g, and the average pore diameter is 5.64nm.

[0199] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0200] Solution E was prepared by mixing 2.05 g of sodium aluminate, 0.70 g of sodium hydroxide and 80 mL of deionized water; solution E was gradually added dropwise to 160 mL of silica gel while stirring; after the white gel was cooled to room temperature, 21.8 mL of hexamethyleneimine was slowly added dropwise and stirring was maintained for 15 minutes; the obtained gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours; after cooling, the obtained product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water to a neutral pH; the white solid was then placed in an oven at 110°C for 12 hours and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain a Na-MCM-22 molecular sieve catalyst; wherein the molar ratio of the silicon source to the aluminum source was 1:0.026.

[0201] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours, and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0202] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.29 cm 3 / g, specific surface area is 391m 2 / g.

[0203] S4. The catalyst is compounded by the following steps:

[0204] The copper-zinc-zirconium-aluminum catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve were mixed in a mass ratio of 1:3:0.3 to obtain a composite catalyst.

[0205] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0206] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0207] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0208] A 60-hour stability evaluation test was conducted using this embodiment. The test results are shown in Table 2.

[0209] Example 8

[0210] This embodiment provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0211] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0212] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 21.47g of zirconium nitrate, 4.69g of aluminum nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 21.12g of sodium hydroxide, 27.98g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is less than 7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0213] The metal-based catalyst has a black solid appearance and a specific surface area of ​​84.62 m 2 / g, pore volume is 0.24cm 3 / g, and the average grain size is 8.62nm.

[0214] S2. The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps:

[0215] 31.20 g of tetraethyl orthosilicate, 22.89 g of tetrapropylammonium hydroxide, 3.2 g of polyethylene glycol and 16 g of deionized water were mixed to prepare solution C, which was placed in an 80°C water bath and stirred thoroughly for 24 hours. 1.04 g of aluminum nitrate, 0.55 g of NaOH and 7.5 mL of deionized water were mixed to prepare solution D. Solution D was gradually added to solution C with a mass ratio of solution C to solution D of 8.06. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 48 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water until the pH was neutral. The white solid was then dried in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain a Na-ZSM-5 molecular sieve catalyst.

[0216] 5 g of Na-ZSM-5 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then dried in an oven at 110°C for 12 hours, and then placed in a muffle furnace and calcined at 550°C for 4 hours to obtain a pore-enlarged HZSM-5 molecular sieve catalyst.

[0217] S3. The preparation method of HMCM-22 molecular sieve catalyst comprises the following steps:

[0218] Solution E was prepared by mixing 2.55 g of sodium metaaluminate, 0.70 g of sodium hydroxide, and 80 mL of deionized water. Solution E was gradually added dropwise to 160 mL of silica gel with stirring. After the white gel cooled to room temperature, 21.8 mL of hexamethyleneimine was slowly added dropwise with stirring for 15 minutes. The resulting gel was transferred to a hydrothermal reactor and placed in an oven at 170°C for static crystallization for 72 hours. After cooling, the resulting product was separated using a high-speed centrifuge to obtain a white solid, which was washed with deionized water to a neutral pH. The white solid was then dried in an oven at 110°C for 12 hours and then calcined in a muffle furnace at 550°C for 4 hours to obtain the Na-MCM-22 molecular sieve catalyst. The molar ratio of the silicon source to the aluminum source was 1:0.033.

[0219] 5 g of Na-MCM-22 molecular sieve was placed in 50 ml of 1 M NH4Cl solution, placed in an 80°C water bath for 3 hours, and the operation was repeated three times; a white solid was then separated using a high-speed centrifuge and washed with deionized water until the pH was neutral; the white solid was then placed in an oven at 110°C for 12 hours, and then placed in a muffle furnace for calcination at 550°C for 4 hours to obtain an HMCM-22 molecular sieve catalyst.

[0220] The HMCM-22 molecular sieve catalyst has the appearance of white powder and a pore volume of 0.28 cm 3 / g, specific surface area of ​​382m 2 / g.

[0221] S4. The catalyst is compounded by the following steps:

[0222] The copper-zinc-zirconium-aluminum catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve were mixed in a mass ratio of 3:2:1 to obtain a composite catalyst.

[0223] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0224] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0225] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0226] Comparative Example 1

[0227] This comparative example provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0228] S1. The preparation method of the metal-based catalyst comprises the following steps:

[0229] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 9.38g of aluminum nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 17.6g of sodium hydroxide, 23.32g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is <7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0230] Commercial HZSM-5 molecular sieve was used. Parameters of commercial ZSM-5 molecular sieve: pore volume 0.340 cm 3 / g, BET specific surface area is 289m 2 / g, the average pore size is 4.71nm, and the silicon / aluminum molar ratio is 50.

[0231] S2. The catalyst is compounded by the following steps:

[0232] The copper-zinc-aluminum catalyst, commercial HZSM-5 molecular sieve, and commercial HMCM-22 molecular sieve (silicon-aluminum ratio 90) were mixed in a mass ratio of 3:1:1 to obtain a composite catalyst.

[0233] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0234] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0235] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0236] Comparative Example 2

[0237] This comparative example provides a composite catalyst for direct production of durene from synthesis gas, as follows:

[0238] S1. The method for preparing a metal-based catalyst by precipitation method comprises the following steps:

[0239] Mix 36.24g of copper nitrate, 22.31g of zinc nitrate, 10.73g of zirconium nitrate, 9.38g of aluminum nitrate and 300mL of deionized water to prepare solution A, place it in a 70°C water bath and stir thoroughly until the solution is clear; mix 17.6g of sodium hydroxide, 23.32g of sodium carbonate and 300mL of deionized water to prepare solution B, and use a peristaltic pump to gradually add solution A and solution B into 100ml of deionized water at the same time, keeping the solution pH = 8, and keep stirring and 70°C water bath during the process; after the precipitation process is completed, age and stir for 0.5h, filter and wash until the filtrate pH is less than 7; the filter cake is placed in an oven and dried at 110°C for 12h, and then placed in a muffle furnace and calcined at 550°C for 4h to obtain a metal-based catalyst.

[0240] S2. The catalyst is compounded by the following steps:

[0241] The copper-zinc-zirconium-aluminum catalyst and commercial HZSM-5 molecular sieve were mixed in a mass ratio of 1:1 to obtain a composite catalyst.

[0242] The composite catalyst prepared above is used to directly produce durene from synthesis gas, and its catalytic performance is evaluated, comprising the following steps:

[0243] The composite catalyst was reduced using a mixed gas (95% N2, 5% H2) at 180°C at normal pressure for 7 h. After the reduction was complete, the temperature was raised to 320°C under a nitrogen atmosphere. Synthesis gas (31% CO, 62% H2, 7% N2) was used in the reaction process, with the back pressure slowly increased to 4.0 MPa and the synthesis gas space velocity controlled at 1350 mL·h -1 ·gcat -1 , maintaining the catalyst bed temperature at 320°C. The synthesis gas fully contacts the composite catalyst, and a series reaction of methanol synthesis and aromatization occurs. The reaction products include nitrogen, carbon monoxide, carbon dioxide, C1-C4 alkanes, aliphatic hydrocarbons, various aromatic hydrocarbons and water.

[0244] The reaction products were analyzed separately after passing through a gas-liquid separator. The liquid product analysis was performed using a clarus 580 gas chromatograph from PerkinElmer, USA, and the gas product analysis was performed using a GC900 gas chromatograph produced by Shanghai Tianpu Instrument. The reaction results are shown in Table 1.

[0245] Comparative Example 3

[0246] This comparative example provides a composite catalyst, and its preparation method is the same as that of Example 1, except that the pore-enlarging agent polyethylene glycol is not added in the preparation of the HZSM-5 molecular sieve.

[0247] The catalytic performance evaluation method of the composite catalyst is the same as that in Example 1, and the results are shown in Table 1.

[0248] Comparative Example 4

[0249] This comparative example provides a composite catalyst, the preparation method of which is the same as that of Example 1, except that polyethylene glycol, a pore-enlarging agent, is added to the preparation of the HZSM-5 molecular sieve, and the HMCM-22 molecular sieve catalyst is not prepared.

[0250] The catalytic performance evaluation method of the composite catalyst is the same as that in Example 1, and the results are shown in Table 1.

[0251] Table 1 Reaction results of direct production of durene from synthesis gas using composite catalyst

[0252]

[0253]

[0254] Note: CO Conv. represents the carbon monoxide conversion rate, other C6-C 10+ Aromatic hydrocarbons include benzene, toluene, xylene, tetramethylbenzene, pentamethylbenzene and hexamethylbenzene.

[0255] Comparative Example 3 shows that the addition of a pore-enlarging agent can improve the selectivity of the target product, durene. Comparative Example 4 shows that the MCM-22 molecular sieve prepared by the present invention can promote the conversion of the reaction products into heavy aromatic hydrocarbons, especially durene.

[0256] Table 2 Stability evaluation results of the composite catalyst of Example 7

[0257] Reaction time CO Conv. / % Distribution of durene in liquid products / % 12h 79.81 37.89 24h 75.44 35.42 36h 79.02 38.11 48h 80.11 39.24 60h 79.24 39.01

[0258] As shown in Table 1, Examples 1-3 evaluated copper-zinc-zirconium catalysts doped with different Zr ratios. As the Zr ratio increased, the specific surface area of ​​the catalyst decreased, resulting in lower CO conversion, but the overall selectivity for durene was good at low conversions. As shown in Table 2, the composite catalyst of the present invention can maintain high conversion and selectivity for an extended period, demonstrating the catalyst's superior stability.

[0259] In Examples 1-8, HMCM-22 molecular sieve catalyst was used for mixing. Compared with the comparative example, the mixture of expanded pore HZSM-5 molecular sieve and HMCM-22 molecular sieve can reduce the generation of aliphatic hydrocarbons.

[0260] Examples 4, 5, and 6 doped the copper-zinc-zirconium catalyst with a small amount of Al. This small amount of aluminum reduced the agglomeration of ZrO2 during the preparation process and increased the catalytic specific surface area and activity. The copper-zinc-zirconium-aluminum catalyst used in the above examples has zirconium as the primary structural additive and aluminum as the secondary structural additive. The specific surface area of ​​the catalyst is slightly lower than that of the copper-zinc-aluminum catalyst. Zirconium oxide dilutes the active component CuZn. By controlling the proportion of ZrO2, the CO conversion rate is controlled to 70-90% at a space velocity suitable for molecular sieve aromatization, which just meets the aromatization and alkylation processing capabilities of the molecular sieve used, thereby achieving excellent selectivity for durene. At the same time, this less active copper-based catalyst has a slower deactivation rate at high temperatures. Accordingly, the expanded pore size of the HZSM-5 molecular sieve facilitates the diffusion of large molecular aromatics, reduces the probability of soft carbon deposits, and further enhances the stability of the molecular sieve. The low-proportion mixed HMCM-22 molecular sieve catalyst facilitates the alkylation process of aromatic products and facilitates the highly selective synthesis of durene.

[0261] Through catalyst design, the present invention effectively addresses the problems of excessive methanation and rapid sintering deactivation of copper-based catalysts at high temperatures. It also optimizes diffusion within the molecular sieve, slows the accumulation of soft carbon deposits, and achieves a more selective durene product by coupling two molecular sieves. The above examples demonstrate the catalytic performance of various modified copper-zinc-zirconium-aluminum catalysts combined with expanded-pore HZSM-5 and HMCM-22 molecular sieve composite catalysts in the one-step synthesis gas to durene production process under various operating conditions, demonstrating excellent catalyst life.

Claims

1. A composite catalyst comprising a metal-based catalyst, an expanded pore HZSM-5 molecular sieve, and an HMCM-22 molecular sieve in a mass ratio of 1:(0.5-3.0):(0.05-0.5); in, The metal-based catalyst includes metal oxide, and the metal elements in the metal oxide include copper, zinc and zirconium in a molar ratio of 3: (1.0-2.0): (0.1-6.0).

2. The composite catalyst according to claim 1, wherein The metal elements in the metal oxide also include aluminum, and the molar ratio of copper, zinc, zirconium and aluminum is 3: (1.0-2.0): (0.1-6.0): (0.3-6.0).

3. The composite catalyst according to claim 1, wherein The specific surface area of ​​the metal-based catalyst is 45-120m 2 / g, pore volume of 0.08-0.23cm 3 / g; Preferably, the pore volume of the expanded HZSM-5 molecular sieve is 0.47-0.65 cm 3 / g.

4. The composite catalyst according to claim 1, wherein The metal-based catalyst is prepared by a coprecipitation method, and the preparation method of the metal-based catalyst comprises the following steps: Mixing a metal mixed solution containing the metal element with an alkaline solution, performing co-precipitation at a pH value of 6.5-8 to obtain a precipitate, and calcining the precipitate at 500-600° C. for 4-8 hours to obtain the metal-based catalyst; Preferably, the coprecipitation temperature is 50-70°C.

5. The composite catalyst according to claim 4, wherein The preparation method of the metal-based catalyst comprises the following steps: Mix water-soluble copper salt, zinc salt, zirconium salt, aluminum salt and water in a molar ratio of 3: (1.0-2.0): (0.01-6.0): (0.01-1.0): (60-600) to prepare solution A; Sodium carbonate, sodium hydroxide and water are mixed in a molar ratio of 1:(0.5-2.0):(100-220) to prepare solution B; The solution A and the solution B are added to water simultaneously, and the pH value of the solution is maintained at 6.5-8.

0. During the process, stirring is maintained and the water bath is kept at 50-70° C. to perform precipitation. After the precipitation is completed, the product is washed to obtain the product, and then dried and calcined in sequence to obtain the metal-based catalyst. The composite catalyst according to claim 1 , wherein The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps: Mixing a first silicon source, a first aluminum source, a template, and a pore-enlarging agent in a molar ratio of 1:(0.07-0.17):(0.1-1):(0.01-0.2) in an alkaline aqueous solution to obtain a first gel; the pore-enlarging agent is polyethylene glycol; The first gel is crystallized and calcined, and the calcined product is ion-exchanged with an ammonium salt and calcined again to obtain the pore-enlarged HZSM-5 molecular sieve.

7. The composite catalyst according to claim 6, wherein In the preparation method of the pore-expanded HZSM-5 molecular sieve, the first silicon source is ethyl orthosilicate; Preferably, the first aluminum source is aluminum nitrate or sodium metaaluminate; Preferably, the template is tetrapropylammonium hydroxide and / or N,N,N-trimethyl-1-adamantylammonium hydroxide.

8. The composite catalyst according to claim 6, wherein In the preparation method of the pore-enlarged HZSM-5 molecular sieve, the crystallization temperature is 120-170°C and the crystallization time is 24-72h; Preferably, the temperature of the two calcinations is 500-600°C and the time is 2-4h; Preferably, the reaction temperature of the ion exchange is 80-95° C., and the reaction time is 3-9 h.

9. The composite catalyst according to claim 6, wherein The preparation method of the pore-enlarged HZSM-5 molecular sieve comprises the following steps: TEOS, tetrapropylammonium hydroxide, polyethylene glycol, and water were mixed in a molar ratio of 1:(0.1-1):(0.01-0.2):(5.0-20.0) to prepare a solution C; Aluminum nitrate, sodium hydroxide, and deionized water were mixed in a molar ratio of 1:(1.0-3.0):(10.0-100.0) to prepare solution D; Solution D was added to solution C, and the resulting gel was subjected to static crystallization, followed by centrifugation, washing, drying, and calcination to obtain a Na-ZSM-5 molecular sieve catalyst; The Na-ZSM-5 molecular sieve is placed in an ammonium nitrate solution for ion exchange, and then centrifuged, washed, dried, and calcined to obtain the pore-enlarged HZSM-5 molecular sieve.

10. The composite catalyst according to claim 1, wherein The preparation method of the HMCM-22 molecular sieve comprises the following steps: Mixing a second silicon source, a second aluminum source, and hexamethyleneimine in a molar ratio of 1:(0.01-0.2):(0.02-0.5) in an alkaline aqueous solution to obtain a second gel; The second gel is crystallized and calcined, and the calcined product is ion-exchanged with an ammonium salt and calcined again to obtain the HMCM-22 molecular sieve. The composite catalyst according to claim 10 , wherein In the preparation method of HMCM-22 molecular sieve, the crystallization temperature is 120-170°C and the crystallization time is 60-84h; Preferably, the temperature of the two calcinations is 500-600°C and the time is 2-4h; Preferably, the reaction temperature of the ion exchange is 70-90° C., and the reaction time is 3-9 h.

12. The composite catalyst according to claim 10, wherein The preparation method of the HMCM-22 molecular sieve comprises the following steps: Sodium metaaluminate, sodium hydroxide, and water were mixed in a molar ratio of 1:(0.01-1.0):(10.0-200.0) to prepare solution E; Solution E was added dropwise to the silica sol, stirred thoroughly and cooled, and then hexamethyleneimine was added. The molar ratio of silica sol to hexamethyleneimine was 1:(0.2-0.5). The resulting gel was subjected to static crystallization, followed by centrifugation, washing, drying, and calcination to obtain a Na-MCM-22 molecular sieve catalyst. The Na-MCM-22 molecular sieve is placed in an ammonium nitrate solution for ion exchange, and then centrifuged, washed, dried, and calcined to obtain the HMCM-22 molecular sieve.

13. The composite catalyst according to claim 1, wherein The particle sizes of the metal-based catalyst, the expanded-pore HZSM-5 molecular sieve, and the HMCM-22 molecular sieve are 20-200 meshes respectively.

14. A method for directly preparing durene from synthesis gas, which is catalyzed by the composite catalyst according to any one of claims 1 to 13.

15. The method for directly preparing durene from synthesis gas according to claim 14, wherein: The steps include: reducing the composite catalyst by using hydrogen; Under the reaction conditions of 280-360℃ and 2-6MPa, the synthesis gas is heated at a rate of 450-3600mL·h -1 ·gcat -1 The space velocity is sufficient to contact with the reduced composite catalyst to react, and the reaction product is subjected to gas-liquid separation to obtain durene in the liquid product; Preferably, the reaction conditions are 300-340° C. and 3-5 MPa.

Images