Method for preparing methyl-ethylbenzene through hydrogenation coupling of carbon dioxide and ethylbenzene

Abstract

The invention discloses a method for preparing methyl-ethylbenzene through hydrogenation coupling of carbon dioxide and ethylbenzene. The preparation method comprises the following steps: enabling mixed gas of carbon dioxide and hydrogen, ethylbenzene and a combined catalyst to be in contact and react to obtain an aromatic hydrocarbon product containing methyl-ethylbenzene, wherein the combined catalyst comprises a first component and a second component; the first component is an oxide with carbon dioxide hydrogenation activity and accounts for 10-90% of the mass fraction of the combined catalyst; and the second component is a zeolite molecular sieve with acid sites and accounts for 10-90% of the mass fraction of the combined catalyst. The catalyst is prepared by combining an oxide material with carbon dioxide hydrogenation performance and a modified zeolite molecular sieve material through a proper method, and high-selectivity methyl ethylbenzene is prepared.

Description

Technical Field

[0001] The present application relates to a method for preparing ethylmethylbenzene by coupling carbon dioxide hydrogenation with ethylbenzene, belonging to the technical field of aromatic hydrocarbon preparation. Background Art

[0002] Ethylmethylbenzene is a raw material for the production of methylstyrene. As a monomer with low toxicity and low volatility, methylstyrene can be widely used in the production of various high-molecular polymers with important industrial application values, such as polymethylstyrene, unsaturated polyester, reinforcing fibers, alkyl coatings, etc., showing superior properties beyond polymers based on common monomers such as styrene. However, its current production capacity is still relatively low, and its large-scale application awaits further upgrading of the upstream and downstream industries.

[0003] Except for a small amount from the separation of reformed C9 aromatics, most of the production of ethylmethylbenzene is obtained by the alkylation reaction of toluene with ethylating reagents such as ethanol or ethylene in the presence of a catalyst. The typical products are three isomers of ethylmethylbenzene with a thermodynamic equilibrium composition and a small amount of other aromatic products (CN104557375A)(CN102503762A)(CN105367373A)(CN105536862A). The main problems are the dependence on high-value high-purity ethanol or ethylene as raw materials and the high energy consumption for product separation.

[0004] Utilizing hydrogen (H 2 ) prepared from industrial waste gas or other sources of CO 2 and renewable energy as raw materials can obtain high-value aromatic hydrocarbon products. The traditional scheme can obtain a relatively high proportion of aromatic hydrocarbon products by combining the modified Fischer-Tropsch (FT) route with zeolite molecular sieve using carbon monoxide as a medium (CN107840778A). Methanol intermediates can also be obtained through an oxide catalyst and then aromatic hydrocarbon products can be obtained through the Methanol to Aromatics (MTA) route (CN113976170A, CN108160104A, CN110743606A). However, none of the above schemes can obtain a single aromatic hydrocarbon product with high selectivity, and there is an inevitable hydrogen transfer reaction, resulting in the formation of a large amount of low-value saturated alkanes, reducing the carbon utilization rate of the reaction. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing ethylmethylbenzene by coupling carbon dioxide hydrogenation with ethylbenzene alkylation using a combined catalyst, opening up a reaction route without using ethanol or ethylene as raw materials, and at the same time overcoming the problem that it is difficult to obtain a single high-value aromatic hydrocarbon product with high selectivity by carbon dioxide hydrogenation.

[0006] In one aspect of the present application, a method for highly selectively preparing methyl ethyl benzene in the reaction of hydrogenating carbon dioxide and coupling with ethyl benzene alkylation is provided. A combined catalyst obtained by combining two key active component materials in a certain combination is used, and carbon dioxide, hydrogen and ethyl benzene vapor are co-fed to obtain an aromatic hydrocarbon product containing methyl ethyl benzene.

[0007] The preparation method includes:

[0008] Contacting a mixed gas of carbon dioxide and hydrogen, ethyl benzene with the combined catalyst to carry out a reaction to obtain an aromatic hydrocarbon product containing methyl ethyl benzene;

[0009] Wherein, the combined catalyst is reduced in a hydrogen atmosphere;

[0010] The combined catalyst includes a first component and a second component;

[0011] The first component is an oxide having carbon dioxide hydrogenation activity, and the mass fraction of the first component in the combined catalyst is 10% - 90%;

[0012] The second component is a zeolite molecular sieve having acidic sites, and the mass fraction of the second component in the combined catalyst is 10% - 90%.

[0013] Optionally, the mass fraction of the first component in the combined catalyst is independently selected from any value in 10%, 30%, 50%, 70%, 90%, 100% or any range value between any two of the above.

[0014] Optionally, the mass fraction of the second component in the combined catalyst is independently selected from any value in 10%, 30%, 50%, 70%, 90%, 100% or any range value between any two of the above.

[0015] This application uses a combined catalyst obtained by combining two or more component materials in a certain combination.

[0016] Optionally, the first component is selected from at least one of oxides of elements of IIIA, IIB, IVB, VIB.

[0017] Optionally, the first component is selected from at least one of oxides of Zn, Zr, Al, Cr, Ga, In.

[0018] Optionally, the first component further includes a carrier, and the oxide is supported on the carrier;

[0019] The carrier is selected from at least one of silica and alumina.

[0020] Optionally, the preparation of the oxide used in this application can be achieved by one or more of the impregnation method, sol-gel method, precipitation method, template method, and mechanical mixing method, including the following steps:

[0021] a. Impregnation method: Using a commercially purchased or pre-prepared oxide material as a carrier, mixing it uniformly with a solution prepared from soluble salts of another metal or multiple metals, and removing the solvent by evaporation or other means;

[0022] Sol-gel method: Mixing soluble salts of one or more metals with specific organic ligands, adjusting parameters such as pH and temperature to form a sol, removing part of the solvent by evaporation or other means, and forming a dry gel at a higher temperature;

[0023] Precipitation method: Preparing a solution from soluble salts of one or more metals, using an alkaline reagent as a precipitant to adjust the pH to precipitate the oxide, with an optional pH range of 5 to 10, preferably 6 to 8; solid-liquid separation is carried out by filtration, centrifugation, etc., and the solid is washed to remove excess ions;

[0024] Template method: Mixing a solution prepared from soluble salts of one or more metals with templates such as activated carbon and silica sol to form a suspension, adjusting the pH to precipitate the metal or evaporating the solvent;

[0025] Mechanical mixing method: Mechanically mixing soluble salts of one or more metals in solid form with an inert carrier by ball milling or other means;

[0026] b. Drying: The temperature is 40 to 150 °C, preferably 80 to 120 °C; under static air, blowing, or vacuum conditions, drying for 2 to 24 h, preferably 8 to 12 h;

[0027] c. Calcination: The temperature is 200 to 800 °C, preferably 200 to 600 °C; in static air, calcining for 2 to 12 h, preferably 4 to 8 h.

[0028] Optionally, the second component mainly consists of silicon, aluminum, and oxygen, and is selected from at least one of H-Y zeolite, H-MCM-22 zeolite, H-ZSM-5 zeolite, H-MOR zeolite, and H-Beta zeolite;

[0029] Optionally, the second component is H-ZSM-5 zeolite;

[0030] Optionally, the silicon-aluminum atomic ratio of the zeolite molecular sieve is 1 to 500.

[0031] Optionally, the silicon-aluminum atomic ratio of the zeolite molecular sieve is 10 to 200.

[0032] Optionally, the silicon-aluminum atomic ratio of the zeolite molecular sieve is 30 to 50.

[0033] Optionally, the silicon-aluminum atomic ratio of the zeolite molecular sieve is independently selected from any value among 1, 10, 30, 40, 50, 100, 150, 200, 300, 400, 500 or any range of values ​​between any two of the above points.

[0034] Optionally, the zeolite molecular sieve is modified by at least one of loading metals and their oxides, non-metals and their oxides, etching, and hydrothermal treatment.

[0035] Optionally, the zeolite molecular sieve is modified by loading non-metal and its oxide.

[0036] Optionally, the zeolite molecular sieve is modified by loading a modifier;

[0037] The modifier is selected from at least one of Zn, Ga, Mg, Mn, Mo, P, and Si.

[0038] Optionally, the modifier is Si.

[0039] Optionally, the mass fraction of the modifier in the zeolite molecular sieve is 0.1% to 20%.

[0040] Optionally, the mass fraction of the modifier in the zeolite molecular sieve is 1% to 10%.

[0041] Optionally, the mass fraction of the modifier in the zeolite molecular sieve is independently selected from any value among 0.1%, 1%, 2%, 4%, 6%, 8%, 10%, 15%, 20% or any range of values ​​between any two of the above points.

[0042] Optionally, the modification method of the zeolite molecular sieve can be achieved by one or more of an impregnation method, a solid phase grinding method, and a chemical deposition method:

[0043] a. Impregnation method: a pre-prepared zeolite molecular sieve material is used as a carrier, a solution prepared with one or more element precursors is mixed with it evenly, and the solvent is removed by evaporation or the like;

[0044] Solid phase grinding method: Precursors of one or more elements and zeolite molecular sieve materials are mechanically mixed by ball milling or other methods;

[0045] Chemical deposition method: disperse the precursor compound containing one or more elements and the zeolite molecular sieve material in a specific solvent, and try to remove the solvent;

[0046] b. Drying: temperature 40 to 150 ° C, preferably 80 to 120 ° C; under still air, blast or vacuum conditions, drying for 2 to 24 hours, preferably 8 to 12 hours;

[0047] c. Calcination: The temperature is 200 - 800 °C, preferably 200 - 600 °C; in static air, calcination is carried out for 2 - 12 h, preferably 4 - 8 h.

[0048] Optionally, the first component and the second component are combined by at least one of powder mechanical grinding and particle physical mixing.

[0049] Optionally, the powder mechanical grinding includes:

[0050] Mechanically grind the oxide powder and the zeolite molecular sieve powder, extrude I, crush, screen I, and mix evenly;

[0051] The time of the mechanical grinding is 1 - 30 min.

[0052] Optionally, the time of the mechanical grinding is 5 - 10 min.

[0053] Optionally, the pressure of the extrusion I is 5 - 30 MPa.

[0054] Optionally, the pressure of the extrusion I is 15 - 20 MPa.

[0055] Optionally, the particle size of the screening I is 10 - 80 mesh.

[0056] Optionally, the particle size of the screening I is 20 - 60 mesh.

[0057] Optionally, the particle physical mixing includes:

[0058] Extrude the oxide powder and the zeolite molecular sieve powder separately for II, crush, screen II, and mix evenly.

[0059] Optionally, the pressure of the extrusion II is 5 - 30 MPa.

[0060] Optionally, the pressure of the extrusion II is 15 - 20 MPa.

[0061] Optionally, the particle size of the screening II is 10 - 80 mesh.

[0062] Optionally, the particle size of the screening II is 20 - 60 mesh.

[0063] As a specific implementation manner, the two key components adopted in this application can be combined by means such as powder mechanical grinding and particle physical mixing:

[0064] a. Powder mechanical grinding: Mix the oxide material and zeolite molecular sieve material powders evenly in an agate mortar, grind for 1 - 30 min, preferably 5 - 10 min; extrude the obtained powder under 5 - 30 MPa, preferably 15 - 20 MPa; crush and screen out particles with a mesh size of 10 - 80 meshes, preferably 20 - 60 meshes.

[0065] b. Particle physical mixing: Extrude the oxide material and zeolite molecular sieve material powders separately under 5 - 30 MPa, preferably 15 - 20 MPa; crush and screen out particles with a mesh size of 10 - 80 meshes, preferably 20 - 60 meshes; mix the two kinds of particles evenly according to the designed ratio.

[0066] Optionally, the combined catalyst used in this application can be diluted or not diluted with inert materials such as quartz sand.

[0067] Optionally, the pressure of the hydrogen atmosphere is 0.1 - 10.0 MPa.

[0068] Optionally, the pressure of the hydrogen atmosphere is independently selected from any value among 0.1 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, 6 MPa, 8 MPa, 10 MPa or any range value between any two of the above.

[0069] Optionally, the reduction temperature is 300 - 600 °C.

[0070] Optionally, the reduction temperature is independently selected from any value among 300 °C, 400 °C, 500 °C, 600 °C or any range value between any two of the above.

[0071] Optionally, the reduction time is 0.5 - 8 h.

[0072] Optionally, the reduction time is 1 - 3 h.

[0073] Optionally, the reduction time is independently selected from any value among 0.5 h, 1 h, 2 h, 3 h, 4 h, 6 h, 8 h or any range value between any two of the above.

[0074] Optionally, the reaction temperature is 200 - 600 °C.

[0075] Optionally, the reaction temperature is 300 - 500 °C.

[0076] Optionally, the reaction temperature is independently selected from any value among 200 °C, 300 °C, 320 °C, 340 °C, 360 °C, 380 °C, 400 °C, 420 °C, 440 °C, 460 °C, 480 °C, 500 °C, 600 °C or any range value between any two of the above.

[0077] Optionally, the pressure of the reaction is 0.5 to 10 MPa.

[0078] Optionally, the pressure of the reaction is 1 to 4 MPa.

[0079] Optionally, the pressure of the reaction is independently selected from any value of 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa, 6 MPa, 8 MPa, 10 MPa or any range value between any two of the above.

[0080] Optionally, the volume ratio of carbon dioxide to hydrogen is 1:1 to 1:6.

[0081] Optionally, the volume ratio of carbon dioxide to hydrogen is 1:3.

[0082] Optionally, the volume ratio of carbon dioxide to hydrogen is independently selected from any value of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6 or any range value between any two of the above.

[0083] Optionally, the mixed gas further includes an inert gas;

[0084] The inert gas is selected from at least one of nitrogen and argon.

[0085] Optionally, the inert gas is argon.

[0086] Optionally, the space velocity of the mixed gas is 600 to 48000 mL g -1 h -1 。

[0087] Optionally, the space velocity of the mixed gas is 6000 to 24000 mL g -1 h -1 。

[0088] Optionally, the space velocity of the mixed gas is independently selected from 600 mL g -1 h -1 、6000 mL g -1 h -1 、12000 mL g -1 h -1 、18000 mL g -1 h -1 、24000 mL g -1 h -1 、30000 mL g -1 h -1 、36000 mL g -1 h -1 、42000 mL g -1 h -1 、48000 mL g-1 h -1 Any range value between.

[0089] Optionally, the mass hourly space velocity of the ethylbenzene is 0.1 - 10 h -1 .

[0090] Optionally, the mass hourly space velocity of the ethylbenzene is 1 - 4 h -1 .

[0091] Optionally, the mass hourly space velocity of the ethylbenzene is independently selected from 0.1 h -1 , 1 h -1 , 2 h -1 , 3 h -1 , 4 h -1 , 6 h -1 , 8 h -1 , 10 h -1 or any range value between any two of the above.

[0092] As a specific implementation, carbon dioxide, hydrogen, and ethylbenzene vapor are co-fed and contacted with a catalyst bed for reaction to obtain an aromatic product containing methyl ethylbenzene. The carbon dioxide - hydrogen mixture can be diluted with a certain proportion of inert gas, and the inert gas can be selected but not limited to nitrogen and argon, preferably argon.

[0093] In the process adopted in this application, the product stream enters a gas - liquid separation device to obtain a liquid - phase product stream mainly composed of aromatic products, and the non - condensable gas stream is vented or can be recycled after purification and separation.

[0094] The beneficial effects that can be produced by this application include:

[0095] (1) This application uses a catalyst composed of an oxide material with carbon dioxide hydrogenation performance and a modified zeolite molecular sieve material combined by an appropriate method to achieve the preparation of highly selective methyl ethylbenzene. This application adopts a reaction route that does not require ethanol or ethylene as raw materials, and at the same time overcomes the problem that it is difficult to obtain a single high - value aromatic product with high selectivity in carbon dioxide hydrogenation, achieving a 10% single - pass conversion rate of carbon dioxide, an ethylbenzene conversion rate of up to 23%, and the total selectivity of methyl ethylbenzene in the liquid - phase product can reach up to 84%, among which the para - isomer accounts for up to 75%.

[0096] (2) This application provides an efficient method for obtaining a higher - yield methyl ethylbenzene product through the carbon dioxide hydrogenation - coupled ethylbenzene alkylation route, overcomes the problems of low yield of methyl ethylbenzene products, high separation energy consumption in the general carbon dioxide hydrogenation route, and the dependence of the alcohol - based or olefin - based alkylation route on high - purity and high - value raw materials, is expected to partially replace the traditional petroleum route, and broadens the catalytic synthesis route for the resource - based conversion of carbon dioxide into high - value aromatic products. Description of the Drawings

[0097] Figure 1 This is the stability evaluation result of this application for 50 hours. Detailed implementation manners

[0098] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.

[0099] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0100] CO in the embodiments of this application 2 The conversion rates of ethylbenzene, the selectivity of CO, and the selectivity of aromatic hydrocarbon products in the liquid-phase products are calculated as follows:

[0101]

[0102]

[0103]

[0104] According to an implementation manner of this application, a combined catalyst obtained by combining two or more active component materials in a certain combination manner is used. The first key component is an oxide material with carbon dioxide hydrogenation activity, accounting for 10% to 90% of the mass of the combined catalyst. The second key component is a zeolite molecular sieve material with acidic sites, accounting for 10% to 90% of the mass of the combined catalyst. Preferably, the mass fraction of the oxide is 30% to 60%, and preferably the mass fraction of the zeolite molecular sieve is 30% to 60%.

[0105] The first key component adopted in this application is an oxide material with carbon dioxide hydrogenation activity, including one or more of the oxides of elements in Group IIIA, IIB, IVB, and VIB. Preferably, it is one or more of the oxides of elements such as Zn, Zr, Al, Cr, Ga, and In. More preferably, it is an oxide containing two elements of metal Zn and Zr.

[0106] The preparation of the oxide adopted in this application can be realized by one or more of the impregnation method, sol-gel method, precipitation method, template method, and mechanical mixing method. The sol-gel method is preferred. A soluble salt of metal Zn and Zr and a specific organic ligand are mixed, and parameters such as pH and temperature are adjusted to form a sol. Part of the solvent is removed by evaporation or the like, and a dry gel is formed at a higher temperature. After calcination, the oxide material is obtained. In this application, the metal salt is preferably one or two of nitrate and acetate, more preferably nitrate. The organic ligand in this application is preferably citric acid. The evaporation temperature is preferably 40 to 120 °C. The temperature for forming the dry gel is preferably 120 to 240 °C. The calcination temperature is preferably 400 to 600 °C, and the time is preferably 4 to 12 h.

[0107] The second key component used in this application is a zeolite molecular sieve material with acidic sites, mainly composed of silicon, aluminum, and oxygen, including one or more of H-Y molecular sieve, H-MCM-22 molecular sieve, H-ZSM-5 molecular sieve, H-MOR molecular sieve, and H-Beta molecular sieve, preferably H-ZSM-5 molecular sieve; the silicon-aluminum atomic ratio of the molecular sieve can be between 1 and 500, preferably between 10 and 200, and more preferably between 30 and 50.

[0108] The zeolite material used in this application can be modified by one or more of the methods such as loading metals and their oxides, non-metals and their oxides, etching, and hydrothermal treatment, preferably modified by metals and their oxides.

[0109] The modification of the zeolite material used in this application can use one or more of the elements such as Zn, Ga, Mg, Mn, Mo, P, Si, etc.; preferably silicon as the modifier, and the added mass fraction can be between 0.1% and 20%, preferably between 1% and 10%. The modification method can be achieved by one or more of the impregnation method, solid-phase grinding method, and chemical deposition method. The preferred modification method is the impregnation method: using a pre-prepared zeolite molecular sieve material as the carrier, mixing it evenly with the organosilicon precursor tetraethyl orthosilicate, removing the solvent by evaporation and other means, and obtaining the modified zeolite molecular sieve material after drying and calcination; the drying temperature is 40 - 150°C, preferably 80 - 120°C, the drying time is 2 - 24h, preferably 8 - 12h; the calcination temperature is 200 - 800°C, preferably 200 - 600°C, and the calcination time is 2 - 12h, preferably 4 - 8h.

[0110] The two key components used in this application can be combined by means such as powder mechanical grinding and particle physical mixing, preferably powder mechanical grinding: mixing the oxide material and the zeolite molecular sieve material powder evenly in an agate mortar, grinding for 1 - 30min, preferably 5 - 10min; extruding the obtained powder at 5 - 30MPa, preferably 15 - 20MPa; crushing, and screening out particles with a mesh size of 10 - 80, preferably 20 - 60.

[0111] The combined catalyst used in this application can be diluted or not diluted with inert materials such as quartz sand, preferably diluted; under a pressure of 0.1 - 10.0MPa and in a hydrogen atmosphere, at a temperature of 300 - 600°C, reduce for 0.5 - 8h, preferably 1 - 3h.

[0112] This application uses carbon dioxide, hydrogen, and ethylbenzene vapor as co-feed, contacts and reacts with the catalyst bed to obtain an aromatic hydrocarbon product containing methyl ethylbenzene.

[0113] The reaction temperature used in this application can be 200 - 600 °C, preferably 300 - 500 °C; the reaction pressure is 0.5 - 10 MPa, preferably 1 - 4 MPa; the carbon dioxide to hydrogen ratio can be 1:1 - 1:6, preferably 1:3; it can be diluted with a certain proportion of inert gas, and the inert gas can be selected but not limited to nitrogen and argon, preferably argon; the space velocity is 600 - 48000 mL g -1 h -1 , preferably 6000 - 24000 mL g -1 h -1 ; the mass space velocity of ethylbenzene is 0.1 - 10 h -1 , preferably 1 - 4 h -1 。

[0114] The specific embodiments of the present invention are specifically described below through specific examples. The described examples are only partial embodiments of the present invention, and all other embodiments obtained by modifying and changing the specific embodiments based on the spirit of the present invention belong to the protection scope of the present invention.

[0115] Example 1

[0116] Catalyst preparation:

[0117] Dissolve 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate in 50 mL of ultrapure water, continuously stir and evaporate the solvent at 90 °C, heat-treat the obtained sol at 180 °C to obtain a xerogel, and calcine it at 500 °C for 10 h to obtain the required oxide material.

[0118] Mix 1 g of H-ZSM-5 zeolite molecular sieve with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stir at 60 °C for 4 h, evaporate the solvent at 80 °C, dry at 120 °C for 12 h, and calcine at 500 °C for 4 h. Repeat the above operations 2 times to obtain a modified zeolite molecular sieve.

[0119] Take equal masses of the oxide and the modified H-ZSM-5 zeolite molecular sieve with a silicon-aluminum atomic ratio of 50, mix them evenly, grind for 15 min, extrude at 15 MPa, crush, and screen out 250 mg of particles with a mesh size of 40 - 60 for standby.

[0120] Performance evaluation:

[0121] The shaped catalyst is diluted with quartz sand at a mass ratio of 1:5, filled into the constant temperature section of the stainless steel tube of the fixed bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature is 320 °C, the pressure is 3 MPa, the volume ratio of carbon dioxide: hydrogen: argon is 23:69:8, and the space velocity is 12000 mL g -1 h -1 , and the mass space velocity of ethylbenzene is 1 h -1 。

[0122] For easy comparison, the reaction results are summarized in Table 1.

[0123] Example 2

[0124] Catalyst preparation:

[0125] Dissolve 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate in 50 mL of ultrapure water, continuously stir and evaporate the solvent at 90 °C, heat-treat the obtained sol at 180 °C to obtain a xerogel, and calcine at 500 °C for 10 h to obtain the required oxide material.

[0126] Mix 1 g of H-ZSM-5 zeolite molecular sieve with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stir at 60 °C for 4 h, evaporate the solvent at 80 °C, dry at 120 °C for 12 h, and calcine at 500 °C for 4 h. Repeat the above operations 2 times to obtain the modified zeolite molecular sieve.

[0127] Take equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silicon-aluminum atomic ratio of 50, mix them evenly, grind for 15 min, extrude at 15 MPa, crush, and screen out 250 mg of particles with a mesh size of 40 - 60 for standby.

[0128] Performance evaluation:

[0129] The shaped catalyst is diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature is 340 °C, the pressure is 3 MPa, the volume ratio of carbon dioxide: hydrogen: argon is 23:69:8, and the space velocity is 12000 mL g -1 h -1 , and the mass hourly space velocity of ethylbenzene is 1 h -1 .

[0130] For easy comparison, the reaction results are summarized in Table 1.

[0131] Example 3

[0132] Catalyst preparation:

[0133] Dissolve 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate in 50 mL of ultrapure water, continuously stir and evaporate the solvent at 90 °C, heat-treat the obtained sol at 180 °C to obtain a xerogel, and calcine at 500 °C for 10 h to obtain the required oxide material.

[0134] 1 g of H-ZSM-5 zeolite molecular sieve was mixed with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stirred at 60 °C for 4 h, the solvent was evaporated at 80 °C, dried at 120 °C for 12 h, calcined at 500 °C for 4 h, and the above operations were repeated 2 times to obtain the modified zeolite molecular sieve.

[0135] Equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silicon-aluminum atomic ratio of 50 were mixed evenly, ground for 15 min, extruded at 15 MPa, crushed, and 250 mg of particles with a mesh size of 40 - 60 were sieved out for standby.

[0136] Performance evaluation:

[0137] The shaped catalyst was diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature was 360 °C, the pressure was 3 MPa, the volume ratio of carbon dioxide:hydrogen:argon was 23:69:8, and the space velocity was 12000 mL g -1 h -1 , and the mass hourly space velocity of ethylbenzene was 1 h -1 .

[0138] For easy comparison, the reaction results are summarized in Table 1.

[0139] Example 4

[0140] Catalyst preparation:

[0141] 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate were dissolved in 50 mL of ultrapure water, and the solvent was continuously stirred and evaporated at 90 °C. The obtained sol was heat-treated at 180 °C to obtain a dry gel, and calcined at 500 °C for 10 h to obtain the required oxide material.

[0142] 1 g of H-ZSM-5 zeolite molecular sieve was mixed with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stirred at 60 °C for 4 h, the solvent was evaporated at 80 °C, dried at 120 °C for 12 h, calcined at 500 °C for 4 h, and the above operations were repeated 2 times to obtain the modified zeolite molecular sieve.

[0143] Equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silicon-aluminum atomic ratio of 50 were mixed evenly, ground for 15 min, extruded at 15 MPa, crushed, and 250 mg of particles with a mesh size of 40 - 60 were sieved out for standby.

[0144] Performance evaluation:

[0145] The shaped catalyst was diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless-steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature was 380 °C, the pressure was 3 MPa, the volume ratio of carbon dioxide: hydrogen: argon was 23:69:8, and the space velocity was 12,000 mL g -1 h -1 , and the mass space velocity of ethylbenzene was 1 h -1 .

[0146] For easy comparison, the reaction results are summarized in Table 1.

[0147] Example 5

[0148] Catalyst preparation:

[0149] 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate were dissolved in 50 mL of ultrapure water, the solvent was continuously stirred and evaporated at 90 °C, the obtained sol was heat-treated at 180 °C to obtain a dry gel, and calcined at 500 °C for 10 h to obtain the required oxide material.

[0150] 1 g of H-ZSM-5 zeolite molecular sieve was mixed with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stirred at 60 °C for 4 h, the solvent was evaporated to dryness at 80 °C, dried at 120 °C for 12 h, and calcined at 500 °C for 4 h. The above operations were repeated 2 times to obtain a modified zeolite molecular sieve.

[0151] An equal mass of the oxide and H-ZSM-5 zeolite molecular sieve with a silicon-aluminum atomic ratio of 50 were mixed evenly, ground for 15 min, extruded at 15 MPa, crushed, and 250 mg of particles with a mesh size of 40 - 60 were screened out for standby.

[0152] Performance evaluation:

[0153] The shaped catalyst was diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless-steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature was 400 °C, the pressure was 3 MPa, the volume ratio of carbon dioxide: hydrogen: argon was 23:69:8, and the space velocity was 12,000 mL g -1 h -1 , and the mass space velocity of ethylbenzene was 1 h -1 .

[0154] For easy comparison, the reaction results are summarized in Table 1.

[0155] Example 6

[0156] Catalyst preparation:

[0157] Dissolve 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate in 50 mL of ultrapure water, continuously stir and evaporate the solvent at 90 °C, heat-treat the obtained sol at 180 °C to obtain a xerogel, and calcine it at 500 °C for 10 h to obtain the required oxide material.

[0158] Mix 1 g of H-ZSM-5 zeolite molecular sieve with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stir at 60 °C for 4 h, evaporate the solvent at 80 °C, dry at 120 °C for 12 h, and calcine at 500 °C for 4 h. Repeat the above operations twice to obtain the modified zeolite molecular sieve.

[0159] Take equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silica-alumina atomic ratio of 50, mix them evenly, grind for 15 min, extrude at 15 MPa, crush, and screen out 250 mg of particles with a mesh size of 40 - 60 for standby.

[0160] Performance evaluation:

[0161] The shaped catalyst is diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless-steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature is 360 °C, the pressure is 0.5 MPa, the volume ratio of carbon dioxide: hydrogen: argon is 23:69:8, and the space velocity is 12000 mL g -1 h -1 , and the mass hourly space velocity of ethylbenzene is 1 h -1 .

[0162] For easy comparison, the reaction results are summarized in Table 1.

[0163] Example 7

[0164] Catalyst preparation:

[0165] Dissolve 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate in 50 mL of ultrapure water, continuously stir and evaporate the solvent at 90 °C, heat-treat the obtained sol at 180 °C to obtain a xerogel, and calcine it at 500 °C for 10 h to obtain the required oxide material.

[0166] Mix 1 g of H-ZSM-5 zeolite molecular sieve with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stir at 60 °C for 4 h, evaporate the solvent at 80 °C, dry at 120 °C for 12 h, and calcine at 500 °C for 4 h. Repeat the above operations twice to obtain the modified zeolite molecular sieve.

[0167] Equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silica-alumina atomic ratio of 50 were mixed evenly, ground for 15 min, extruded under 15 MPa, crushed, and 250 mg of particles with a mesh size of 40 - 60 were screened out for standby.

[0168] Performance evaluation:

[0169] The shaped catalyst was diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless-steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h under a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature was 360 °C, the pressure was 1.0 MPa, the volume ratio of carbon dioxide: hydrogen: argon was 23:69:8, and the space velocity was 12000 mL g -1 h -1 , and the mass space velocity of ethylbenzene was 1 h -1 .

[0170] For easy comparison, the reaction results are summarized in Table 1.

[0171] Example 8

[0172] Catalyst preparation:

[0173] 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate, and 7.56 g of citric acid monohydrate were dissolved in 50 mL of ultrapure water, and the solvent was continuously stirred and evaporated at 90 °C. The obtained sol was heat-treated at 180 °C to obtain a dry gel, and calcined at 500 °C for 10 h to obtain the required oxide material.

[0174] 1 g of H-ZSM-5 zeolite molecular sieve was mixed with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stirred at 60 °C for 4 h, the solvent was evaporated to dryness at 80 °C, dried at 120 °C for 12 h, and calcined at 500 °C for 4 h. The above operations were repeated 2 times to obtain the modified zeolite molecular sieve.

[0175] Equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silica-alumina atomic ratio of 50 were mixed evenly, ground for 15 min, extruded under 15 MPa, crushed, and 250 mg of particles with a mesh size of 40 - 60 were screened out for standby.

[0176] Performance evaluation:

[0177] The shaped catalyst was diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless-steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h under a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature was 360 °C, the pressure was 2.0 MPa, the volume ratio of carbon dioxide: hydrogen: argon was 23:69:8, and the space velocity was 12000 mL g -1 h -1 , and the mass space velocity of ethylbenzene was 1 h -1 .

[0178] For easy comparison, the reaction results are summarized in Table 1.

[0179] Example 9

[0180] Catalyst preparation:

[0181] Dissolve 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate in 50 mL of ultrapure water, continuously stir and evaporate the solvent at 90 °C. The obtained sol is heat-treated at 180 °C to obtain a xerogel, and calcined at 500 °C for 10 h to obtain the required oxide material.

[0182] Mix 1 g of H-ZSM-5 zeolite molecular sieve with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stir at 60 °C for 4 h, evaporate the solvent at 80 °C, dry at 120 °C for 12 h, and calcine at 500 °C for 4 h. Repeat the above operations 2 times to obtain the modified zeolite molecular sieve.

[0183] Take equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silica-alumina atomic ratio of 50, mix them evenly, grind for 15 min, extrude at 15 MPa, crush, and screen out 250 mg of particles with a mesh size of 40 - 60 for standby.

[0184] Performance evaluation:

[0185] The shaped catalyst is diluted with quartz sand at a mass ratio of 1:5, filled into the constant temperature section of the stainless steel tube of the fixed bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature is 360 °C, the pressure is 3 MPa, the volume ratio of carbon dioxide: hydrogen: argon is 23:69:8, and the space velocity is 6000 mL g -1 h -1 , and the mass space velocity of ethylbenzene is 1 h -1 .

[0186] For easy comparison, the reaction results are summarized in Table 1.

[0187] Example 10

[0188] Catalyst preparation:

[0189] Dissolve 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate in 50 mL of ultrapure water, continuously stir and evaporate the solvent at 90 °C. The obtained sol is heat-treated at 180 °C to obtain a xerogel, and calcined at 500 °C for 10 h to obtain the required oxide material.

[0190] 1 g of H-ZSM-5 zeolite molecular sieve was mixed with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stirred at 60 °C for 4 h, the solvent was evaporated at 80 °C, dried at 120 °C for 12 h, calcined at 500 °C for 4 h, and the above operations were repeated 2 times to obtain the modified zeolite molecular sieve.

[0191] Equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silicon-aluminum atomic ratio of 50 were mixed evenly, ground for 15 min, extruded at 15 MPa, crushed, and 250 mg of particles with a mesh size of 40 - 60 were sieved out for standby.

[0192] Performance evaluation:

[0193] The shaped catalyst was diluted with quartz sand at a mass ratio of 1:5, filled into the isothermal section of the stainless steel tube of the fixed-bed reactor, pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa, the reaction temperature was 360 °C, the pressure was 3 MPa, the volume ratio of carbon dioxide: hydrogen: argon was 23:69:8, and the space velocity was 18000 mL g -1 h -1 , and the mass space velocity of ethylbenzene was 1 h -1 .

[0194] For easy comparison, the reaction results are summarized in Table 1.

[0195] Comparative Example 1

[0196] Catalyst preparation:

[0197] 6.87 g of zirconium nitrate pentahydrate, 0.60 g of zinc nitrate hexahydrate and 7.56 g of citric acid monohydrate were dissolved in 50 mL of ultrapure water, and the solvent was continuously stirred and evaporated at 90 °C. The obtained sol was heat-treated at 180 °C to obtain a dry gel, and calcined at 500 °C for 10 h to obtain the required oxide material.

[0198] 1 g of H-ZSM-5 zeolite molecular sieve was mixed with 20 mL of cyclohexane solution containing 0.5 mL of tetraethyl orthosilicate, stirred at 60 °C for 4 h, the solvent was evaporated at 80 °C, dried at 120 °C for 12 h, calcined at 500 °C for 4 h, and the above operations were repeated 2 times to obtain the modified zeolite molecular sieve.

[0199] Equal masses of the oxide and H-ZSM-5 zeolite molecular sieve with a silicon-aluminum atomic ratio of 50 were mixed evenly, ground for 15 min, extruded at 15 MPa, crushed, and 250 mg of particles with a mesh size of 40 - 60 were sieved out for standby.

[0200] Performance evaluation:

[0201] The shaped catalyst was diluted with quartz sand at a mass ratio of 1:5 and filled into the constant temperature section of the stainless steel tube of the fixed bed reactor. It was pretreated at 500 °C for 2 h in a hydrogen atmosphere with a pressure of 0.1 MPa. The reaction temperature was 360 °C, the pressure was 3 MPa, and the volume ratio of carbon dioxide:hydrogen:argon was 23:69:8, and the space velocity was 12000 mL g -1 h -1 。

[0202] For easy comparison, the reaction results are summarized in Table 1.

[0203] Table 1

[0204]

[0205] From the results in Table 1, it can be seen from the results of Examples 1-5 that as the reaction temperature increases, the conversion rate continuously increases, and the product selectivity first increases and then decreases; from the results of Examples 6-8, it can be seen that as the reaction pressure increases, the conversion rate and the product selectivity increase synchronously; from Examples 9-10, it can be seen that the increase in the space velocity leads to a decrease in the conversion rate, but can improve the product selectivity. The comparative example shows that the ratio of the target product methyl ethylbenzene is very low when ethylbenzene is not involved, proving that the co-feed of ethylbenzene is essential for the formation of methyl ethylbenzene.

[0206] Test example

[0207] The catalyst obtained in Example 1 was evaluated for its stability for 50 hours. The test conditions were: reaction temperature 360 °C, pressure 3 MPa, volume ratio of carbon dioxide:hydrogen:argon 23:69:8, space velocity 12000 mL g -1 h -1 。

[0208] The test results are shown in Figure 1 ,from which Figure 1 it can be seen that the activity and selectivity of the catalyst only fluctuate within a small range during 50 h, and no obvious deactivation occurs, proving its good stability and potential application value.

[0209] The above are only several embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are all equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for preparing styrene by coupling hydrogenation of carbon dioxide with ethylbenzene, characterized in that, the method comprises: bringing a mixed gas of carbon dioxide and hydrogen, and ethylbenzene into contact with a combined catalyst to react, obtaining an aromatic hydrocarbon product containing styrene; wherein, the combined catalyst is reduced in a hydrogen atmosphere; the combined catalyst comprises a first component and a second component; the first component is an oxide having carbon dioxide hydrogenation activity, accounting for 10% - 90% of the mass of the combined catalyst; the second component is a zeolite molecular sieve having acidic sites, accounting for 10% - 90% of the mass of the combined catalyst.

2. The method according to claim 1, characterized in that, the first component is selected from at least one of oxides of elements of Group IIIA, IIB, IVB, and VIB; preferably, the first component is selected from at least one of oxides of Zn, Zr, Al, Cr, Ga, and In; preferably, the first component further comprises a carrier, and the oxide is supported on the carrier; the carrier is selected from at least one of silica and alumina.

3. The method according to claim 1, characterized in that, the second component is selected from at least one of H-Y molecular sieve, H-MCM-22 molecular sieve, H-ZSM-5 molecular sieve, H-MOR molecular sieve, and H-Beta molecular sieve; preferably, the second component is H-ZSM-5 molecular sieve; preferably, the silicon-aluminum atomic ratio of the zeolite molecular sieve is 1 - 500, preferably 10 - 200, more preferably 30 - 50.

4. The method according to claim 1, characterized in that, the zeolite molecular sieve is modified by at least one method of loading metals and their oxides, non-metals and their oxides, etching, and hydrothermal treatment; preferably, the zeolite molecular sieve is modified by loading non-metals and their oxides.

5. The method according to claim 1, characterized in that, the zeolite molecular sieve is modified by loading a modifier; the modifier is selected from at least one of Zn, Ga, Mg, Mn, Mo, P, and Si; preferably, the modifier is Si; preferably, the mass fraction of the modifier in the zeolite molecular sieve is 0.1% - 20%; preferably, the mass fraction of the modifier in the zeolite molecular sieve is 1% - 10%.

6. The method according to claim 1, characterized in that, the first component and the second component are combined by at least one of powder mechanical grinding and particle physical mixing.

7. The method according to claim 6, characterized in that: the powder mechanical grinding comprises: mechanically grinding the oxide powder and the zeolite molecular sieve powder, extruding I, crushing, screening I, and mixing evenly; the time of the mechanical grinding is 1 - 30 min, preferably 5 - 10 min; the pressure of the extrusion I is 5 - 30 MPa, preferably 15 - 20 MPa; the particle size of the screening I is 10 - 80 mesh, preferably 20 - 60 mesh.

8. The method according to claim 6, characterized in that, the particle physical mixing comprises: The oxide powder and the zeolite molecular sieve powder are respectively extruded II, crushed, screened II, and mixed evenly; The pressure of the extrusion II is 5 - 30 MPa, preferably 15 - 20 MPa; The particle size of the screening II is 10 - 80 mesh, preferably 20 - 60 mesh.

9. According to the method described in claim 1, it is characterized in that, the pressure of the hydrogen atmosphere is 0.1 - 10.0 MPa; the temperature of the reduction is 300 - 600 °C; the time of the reduction is 0.5 - 8 h, preferably 1 - 3 h.

10. According to the method described in claim 1, it is characterized in that, the temperature of the reaction is 200 - 600 °C, preferably 300 - 500 °C; the pressure of the reaction is 0.5 - 10 MPa, preferably 1 - 4 MPa; Preferably, the volume ratio of carbon dioxide to hydrogen is 1:1 - 1:6, preferably 1:3; Preferably, the mixed gas further includes an inert gas; The inert gas is selected from at least one of nitrogen and argon, preferably argon; Preferably, the space velocity of the mixed gas is 600 - 48000 mL g -1 h -1 , preferably 6000 - 24000 mL g -1 h -1 ; Preferably, the mass hourly space velocity of ethylbenzene is 0.1 to 10 h -1 , preferably 1 to 4 h -1 .

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