A method for preparing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons

Abstract

The application provides a method for preparing ethylbenzene and propylbenzene by reacting carbon dioxide and light hydrocarbon, which comprises the following steps: taking light hydrocarbon and carbon dioxide as raw materials, taking a basic nanometer ZSM-5 / ZSM-11 eutectic molecular sieve loaded with magnesium as a catalyst, and performing catalytic reaction under the action of supergravity, so that liquid-phase products containing ethylbenzene and propylbenzene are obtained, wherein the reaction temperature is 300-400 DEG C. In the application, carbon dioxide and light hydrocarbon are taken as raw materials, a basic nanometer ZSM-5 / ZSM-11 eutectic molecular sieve loaded with magnesium is taken as a catalyst, and the coupling modification reaction of the dehydrogenation reaction of light hydrocarbon and carbon dioxide is utilized, so that ethylbenzene and propylbenzene with higher added value and rich hydrogen are prepared.

Description

Technical Field

[0001] This invention belongs to the field of carbon dioxide conversion technology and relates to a method for preparing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons. Background Technology

[0003] Currently, numerous researchers have proposed technological pathways for the utilization of carbon dioxide. Chinese invention patent CN114160183B discloses the preparation of a sheet-like HZSM-5 molecular sieve catalyst and its application in the hydrogenation of carbon dioxide to aromatics. By adding the mineralizing agent NH4F and adjusting the molar ratio of urea and NH4F, precise control of the thickness of the synthesized HZSM-5 molecular sieve is achieved, resulting in a sheet-like HZSM-5 molecular sieve. The HZSM-5 molecular sieve has a large specific surface area and high total acidity. Due to its relatively short b-axis length, it facilitates mass transport and diffusion, making it easier for reactants to enter the active sites and suppressing side reactions. When used in the CO2 hydrogenation reaction, it exhibits good catalytic activity.

[0004] Chinese invention patent CN114950534B discloses a process for the catalytic hydrogenation of carbon dioxide to produce aromatics using a bifunctional catalyst. This invention places the bifunctional catalyst in the isothermal section of a fixed-bed reactor, introduces hydrogen gas, raises the temperature for reduction, lowers the temperature, introduces feed gases H2 and CO2, and after pressurization and heating, carries out a catalytic reaction to obtain the product. The bifunctional catalyst is a mixture of a metal oxide catalyst and a molecular sieve catalyst in a mass ratio of 1:(0.2~4). The metal oxide catalyst uses alumina as a support, transition metals as the active component, and alkali metals as co-active components, with a mass ratio of alumina, transition metal oxides, and alkali metal oxides of 1:(2~8):(0.5~1). The molecular sieve catalyst is a composite of SAPO-n molecular sieves and HZSM-5 molecular sieves in a mass ratio of 1:(0.5~2). The bifunctional catalyst provided by this invention catalyzes the hydrogenation of carbon dioxide to produce mixed aromatics.

[0005] Among the aforementioned technologies for converting carbon dioxide into high-value-added chemical products, most of them use an intermediate route of converting to methanol under hydrogenation conditions. This not only consumes hydrogen resources but also results in low carbon dioxide conversion rates and a wide distribution of products.

[0006] Light hydrocarbons mainly refer to reformate residue oil, reformate topping oil, pentane oil, and hydrocracking naphtha, which are mainly composed of n-alkanes and have low added value, such as high saturated vapor pressure and low octane number. With the inevitable trend of fuel enterprises transforming from oil refining to chemical industry, it is crucial to realize the rational and efficient conversion and utilization of light hydrocarbon resources.

[0007] Converting carbon dioxide and light hydrocarbons into basic chemical raw materials under the action of catalysts not only provides a technical path to solve environmental problems such as the greenhouse effect caused by carbon dioxide, but also achieves efficient conversion and utilization of light hydrocarbons, which has important academic research value and broad prospects for promotion and application.

[0008] Chinese patent application CN115845908A discloses a method for the coupled conversion of naphtha and carbon dioxide to produce benzene, toluene, and p-xylene. The method involves passing raw materials containing naphtha and CO2 into a reactor equipped with a zeolite molecular sieve catalyst. However, the reaction products are benzene, toluene, and p-xylene, which can only be used as basic chemical raw materials with limited added value. Summary of the Invention

[0009] In order to solve the problems of the prior art, the purpose of this invention is to provide a method for preparing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons. This method can produce high-value-added ethylbenzene and propylbenzene and generate abundant hydrogen gas.

[0010] This invention is achieved through the following technical solution: A method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons includes: using light hydrocarbons and carbon dioxide as raw materials, using magnesium-supported alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieves as catalysts, carrying out a catalytic reaction under the action of supergravity, with a reaction temperature of 300~400℃, to obtain a liquid-phase product containing ethylbenzene and propylbenzene.

[0011] Preferably, the hypergravity level is 200~500g.

[0012] Preferably, the alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is an alkaline nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve.

[0013] Furthermore, the alkaline nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve is a sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve.

[0014] Preferably, the molar silica-alumina ratio of the alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is 300~600.

[0015] Preferably, the preparation method of the magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is as follows: the alkaline ZSM-5 / ZSM-11 eutectic molecular sieve is mixed with a binder, a compound containing Mg is added, the mixture is mechanically mixed evenly, and then bound and extruded using a dilute nitric acid solution. After drying and calcination, the magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is obtained.

[0016] Furthermore, in the preparation method of the magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve, the calcination temperature is 400~800 ℃ and the calcination time is 5~12 h.

[0017] Preferably, in the magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve, the magnesium loading is 10% to 40% of the mass of the alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve.

[0018] Preferably, the mass ratio of carbon dioxide to light hydrocarbons is 1:(0.5~9.5).

[0019] Preferably, the light hydrocarbon is one or more of the following: reforming raffinate oil, reforming topping oil, pentane oil, n-butane, isobutane, n-pentane, isopentane, cyclopentane, n-hexane, cyclohexane, and isohexane.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention uses carbon dioxide and light hydrocarbons as raw materials and magnesium-supported basic nano-ZSM-5 / ZSM-11 eutectic molecular sieves as catalysts. It utilizes the dehydrogenation reaction of light hydrocarbons coupled with a carbon dioxide-based reforming reaction to produce ethylbenzene and propylbenzene with higher added value and rich hydrogen production. Firstly, the unique pore structure of the basic nano-ZSM-5 / ZSM-11 eutectic molecular sieves (combining the "Z"-shaped pores of ZSM-5 molecular sieves and the straight pores of ZSM-11 molecular sieves) improves the selectivity of the larger molecular products ethylbenzene and propylbenzene. Furthermore, the introduction of magnesium increases the number of basic sites on the catalyst and provides an optimal oxygen vacancy concentration, offering more suitable active sites for the formation of ethylbenzene and propylbenzene. Secondly, by utilizing the effects of supergravity, the mass and heat transfer efficiency of materials during the reaction is enhanced, promoting the instantaneous diffusion of hydrogen generated in the dehydrogenation reaction and providing a hydrogen-rich environment. This facilitates the coupling and modification of carbon dioxide with light hydrocarbons, improving reaction efficiency and lowering the reaction temperature. Furthermore, the heat and mass coupling modification between CO2 and light hydrocarbons allows the reaction to proceed at a lower temperature, resulting in low energy consumption and environmental friendliness. Thirdly, the reaction temperature significantly affects the distribution of reaction products. Within the 300-400℃ range specified in this invention, high yields of ethylbenzene and propylbenzene can be obtained. However, above 400℃, further reactions occur, yielding more compounds such as tetramethylbenzene. Therefore, the reaction temperature in this invention should be controlled within 300-400℃. Ethylbenzene and propylbenzene, as important chemical intermediates for the production of fine chemicals, are widely used in chemical production and healthcare, possessing high added value. This method features a simple reaction process, no hydrogen consumption, high raw material conversion rate, narrow product distribution, and high selectivity, providing a new technological pathway for the conversion and utilization of carbon dioxide, with promising prospects for development and widespread application.

[0021] Furthermore, the alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve has a molar silica-alumina ratio of 300~600 and is relatively weakly acidic, which can provide a better alkaline environment for the reaction. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of a method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons, and co-producing hydrogen.

[0024] In the diagram, 1 represents light hydrocarbons; 2 represents a light hydrocarbon pump; 3 represents carbon dioxide; 4 represents a carbon dioxide flow meter; 5 represents a preheater; 6 represents a high-gravity reactor; 7 represents a reaction product cooler; 8 represents a reaction product separator; 9 represents a light component cooler; 10 represents a light component condensate separator; 11 represents C1-C4 gases + hydrogen; 12 represents ethylbenzene + propylbenzene; 13 represents circulating water inlet; 14 represents circulating water return; 15 represents chilled water inlet; 16 represents chilled water return; and 17 represents a gravity flow line for condensate. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the inventive concept of the present invention.

[0026] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art. Unless otherwise specified, the raw materials used in this invention have a purity greater than 99% and do not require purification.

[0027] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0028] The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to the present invention includes: using light hydrocarbons and carbon dioxide as raw materials, using magnesium-supported alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieves as catalysts, carrying out a catalytic reaction under the action of supergravity, with a reaction temperature of 300~400℃, to obtain a liquid phase product containing ethylbenzene and propylbenzene.

[0029] In specific implementation of this invention, the reaction system used is as follows: Figure 1 As shown, the system includes a light hydrocarbon pump 2, a carbon dioxide flow meter 4, a preheater 5, a hypergravity reactor 6, a reaction product cooler 7, a reaction product separation tank 8, a light component cooler 9, and a light component condensate separation tank 10. Light hydrocarbons 1 output from the light hydrocarbon pump 2 and carbon dioxide 3 output from the carbon dioxide flow meter 4 are mixed and then enter the preheater 5 for preheating. The preheated mixture enters the hypergravity reactor 6, where a catalytic reaction is carried out under the action of a catalyst. After the reaction, the material enters the reaction product cooler for condensation after passing through the preheater 5. The condensed liquid product, rich in ethylbenzene and propylbenzene, enters the reaction product separation tank 8. Ethylbenzene + propylbenzene 12 is output from the bottom of the reaction product separation tank 8. The gaseous product is cooled by the light component cooler 9 and then enters the light component condensate separation tank 10. The condensed liquid phase returns to the reaction product separation tank 8 via the condensate gravity flow line 17. The top outlet of the light component condensate separation tank 10 outputs C1-C4 gas + hydrogen 11. The cold fluid pipeline of the reaction product cooler 7 has a circulating water inlet 13 and a circulating water return 14 at both ends; the cold fluid pipeline of the light component cooler 9 has a chilled water inlet 15 and a chilled water return 16 at both ends.

[0030] The reactor used in this invention is a hypergravity reactor, primarily designed to simulate hypergravity conditions during the reaction process. The specific type of reactor is not strictly limited. A hypergravity environment refers to an environment with an acceleration greater than Earth's gravity, g = 9.8 m / s². 2In much larger environments, on Earth, hypergravity is primarily achieved through the centrifugal force generated by the high-speed rotation of objects. The basic principle of a hypergravity reactor is to establish a hypergravity environment through centrifugal force, making the gas phase a continuous phase and the liquid phase a dispersed phase within the reactor. Under hypergravity, the liquid disperses or breaks into extremely fine droplets, thin lines, and thin films under the strong shear force of the packing material within the reactor, thereby greatly enhancing the mass transfer between the liquid and gas.

[0031] This invention utilizes the effect of supergravity to enhance the mass and heat transfer efficiency of materials during the reaction process, promotes the instantaneous diffusion of hydrogen generated by the dehydrogenation reaction, provides a hydrogen-rich environment, and facilitates the coupling and upgrading of carbon dioxide reaction with light hydrocarbons, thereby improving reaction efficiency and reducing the steps of adding additional hydrogen to the reaction system during the reaction process. Compared with traditional carbon dioxide conversion and utilization technologies, this invention is more energy-efficient and environmentally friendly.

[0032] In the specific reaction, the catalyst bed is provided by the rotor catalyst bed loaded into the hypergravity reactor. The preheated mixture enters the catalyst bed of the hypergravity reactor and undergoes a catalytic reaction under hypergravity conditions.

[0033] Specifically, different levels of hypergravity can be obtained by adjusting the speed of the rotor. The preferred hypergravity level used in this invention is 200~500g.

[0034] In some specific embodiments of the present invention, the temperature of the preheater is 100~200℃ and the temperature of the cooler is -10~0℃.

[0035] The reaction conditions in the centrifugal reactor were: reaction temperature 300–400 °C, atmospheric pressure, and total space velocity 0.1–1.0 h⁻¹. -1 .

[0036] The light hydrocarbons described in this invention are one or more of the following: reforming raffinate oil, reforming topping oil, pentane oil, n-butane, isobutane, n-pentane, isopentane, cyclopentane, n-hexane, cyclohexane, and isohexane.

[0037] In the method of the present invention, the mass ratio of carbon dioxide to light hydrocarbons is 1:(0.4~9.5).

[0038] In the method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to the present invention, the alkaline nano-ZSM-5 / ZSM-11 eutectic molecular sieve used is specifically an alkaline nano-rod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve, for example, a sodium-type nano-rod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve. The molar silica-alumina ratio of the alkaline nano-ZSM-5 / ZSM-11 eutectic molecular sieve is 300-600, preferably 450-600. The acid-base properties of the molecular sieve affect the reaction process; stronger acidic molecular sieves favor the formation of smaller molecules, such as benzene and toluene, while alkaline molecular sieves favor the formation of larger molecules, ethylbenzene and propylbenzene.

[0039] The introduction of magnesium increases the number of basic sites in the catalyst while maintaining an optimal oxygen vacancy concentration, providing more suitable active sites for the generation of ethylbenzene and propylbenzene.

[0040] The magnesium-loaded alkaline nano-ZSM-5 / ZSM-11 eutectic molecular sieve can be prepared by the following steps: Alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieves are mixed with a binder, and a compound containing Mg is added. The mixture is mechanically mixed evenly, and then bound and extruded using a 2%~4% dilute nitric acid solution. Finally, the mixture is dried and calcined.

[0041] Specifically, the binder is either alumina (such as boehmite) or silica sol, and the mass ratio of alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve to binder is (6~9):(1~4).

[0042] Specifically, the compound containing Mg is magnesium nitrate, and the magnesium loading is 10% to 40% of the mass of the alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve, based on the mass of Mg.

[0043] In the preparation method of magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieves, the drying temperature can be room temperature to 150 ℃, and the drying time can be 24 to 48 h; the calcination temperature can be 400 to 800 ℃, and the calcination time can be 5 to 12 h.

[0044] Example 1 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve with a molar silicon-to-aluminum ratio of 480 was used as a catalyst. Magnesium nitrate with a magnesium loading of 24% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve and boehmite as a binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve to boehmite was 7:3. The mixture was bound and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0045] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 300g. The reaction was carried out at 350℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil, a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio), and a total mass hourly space velocity of 0.5. The reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, yielding the following results: carbon dioxide conversion rate of 36.7%, total ethylbenzene and propylbenzene selectivity of 79.4%, and hydrogen selectivity of 15.6%.

[0046] Example 2 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 460 were used as catalysts. Magnesium nitrate was weighed according to a 15% magnesium loading and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and boehmite as a binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to boehmite was 6:4. The mixture was bound and extruded into strips with a 2% dilute nitric acid solution, then dried at 110℃ for 8 hours and calcined at 580℃ for 8 hours to obtain the catalyst required for the reaction.

[0047] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 200g. At 400℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil and a carbon dioxide:light hydrocarbon ratio of 1:9 (mass ratio) and a total hourly space velocity of 0.8, the reactants were preheated at 120℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 29.7%, total ethylbenzene and propylbenzene selectivity of 84.2%, and hydrogen selectivity of 11.3%.

[0048] Example 3 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 600 were used as catalysts. Magnesium nitrate with 18% magnesium loading was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and silica sol binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to silica sol was 8:2. The mixture was bound and extruded with 3% dilute nitric acid solution, then dried at 150℃ for 8 hours and calcined at 600℃ for 6 hours to obtain the catalyst required for the reaction.

[0049] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 240g. The reaction was carried out at 380℃ and atmospheric pressure, with the light hydrocarbons being reformed topping oil, a carbon dioxide:light hydrocarbon ratio of 3:7 (mass ratio), and a total hourly space velocity of 0.9. The reactants were preheated at 160℃ in a preheater before the reaction proceeded in the hypergravity reactor. After 6 hours of reaction, the products were analyzed, yielding the following results: carbon dioxide conversion rate of 36.2%, total ethylbenzene and propylbenzene selectivity of 82.3%, and hydrogen selectivity of 23.8%.

[0050] Example 4 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 500 were used as catalysts. Magnesium nitrate with a magnesium loading of 14% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and silica sol binder, wherein the mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to silica sol was 9:1. The mixture was bound and extruded into strips with a 3% dilute nitric acid solution, then dried at 100℃ for 24 h and calcined at 480℃ for 10 h to obtain the catalyst required for the reaction.

[0051] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 380g. At 340℃ and atmospheric pressure, with pentane oil as the light hydrocarbon and a carbon dioxide:light hydrocarbon ratio of 3:7 (mass ratio) and a total space velocity of 0.6, the reactants were preheated at 150℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 29.5%, total ethylbenzene and propylbenzene selectivity of 86.7%, and hydrogen selectivity of 18.3%.

[0052] Example 5 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 580 were used as catalysts. Magnesium nitrate with a 20% magnesium loading was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and silica sol as a binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to silica sol was 7:3. The mixture was bound and extruded with a 4% dilute nitric acid solution, then dried at 160℃ for 20 h and calcined at 580℃ for 12 h to obtain the catalyst required for the reaction.

[0053] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 360g. At 320℃ and normal pressure, with pentane oil as the light hydrocarbon and a carbon dioxide:light hydrocarbon ratio of 1:9 (mass ratio) and a total space velocity of 0.4, the reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 19.7%, total ethylbenzene and propylbenzene selectivity of 90.9%, and hydrogen selectivity of 20.5%.

[0054] Example 6 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 480 were used as catalysts. Magnesium nitrate with a magnesium loading of 30% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and silica sol as a binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to silica sol was 6:4. The mixture was bound and extruded into strips with a 4% dilute nitric acid solution, then dried at 180℃ for 12 h and calcined at 550℃ for 10 h to obtain the catalyst required for the reaction.

[0055] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 280g. At 400℃ and normal pressure, with pentane oil as the light hydrocarbon and a carbon dioxide:light hydrocarbon ratio of 3:7 (mass ratio) and a total space velocity of 0.6, the reactants were preheated to 180℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 39.7%, total ethylbenzene and propylbenzene selectivity of 83.5%, and hydrogen selectivity of 12.8%.

[0056] Example 7 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 520 were used as catalysts. Magnesium nitrate with a 10% magnesium loading was mechanically mixed with the sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and the binder silica sol, wherein the mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to silica sol was 7:3. The mixture was bound and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 36 h and calcined at 650℃ for 10 h to obtain the catalyst required for the reaction.

[0057] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 400g. The reaction was carried out at 390℃ and atmospheric pressure, with the light hydrocarbon being reformed topping oil, a carbon dioxide:light hydrocarbon ratio of 5:5 (mass ratio), and a total space velocity of 0.3. The reactants were preheated to 150℃ in a preheater before the reaction proceeded in the hypergravity reactor. After 6 hours of reaction, the products were analyzed, yielding the following results: carbon dioxide conversion rate of 40.5%, total ethylbenzene and propylbenzene selectivity of 79.8%, and hydrogen selectivity of 19.2%.

[0058] Example 8 Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 500 were used as catalysts. Magnesium nitrate with a magnesium loading of 35% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and boehmite binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to silica sol was 8:2. The mixture was bonded and extruded with a 3% dilute nitric acid solution, then dried at 120℃ for 24 h and calcined at 720℃ for 5 h to obtain the catalyst required for the reaction.

[0059] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 460g. At 335℃ and atmospheric pressure, with reformed topping oil as the light hydrocarbon, a carbon dioxide:light hydrocarbon ratio of 7:3 (mass ratio), and a total space velocity of 0.4, the reactants were preheated at 140℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 38.7%, total ethylbenzene and propylbenzene selectivity of 81.5%, and hydrogen selectivity of 26.5%.

[0060] Comparative Example 1: The high-gravity reactor in Example 1 was replaced with a fixed-bed reactor. Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve with a molar silicon-to-aluminum ratio of 480 was used as a catalyst. Magnesium nitrate with a magnesium loading of 24% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve and boehmite as a binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve to boehmite was 7:3. The mixture was bound and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0061] The prepared catalyst was loaded into a fixed-bed reactor. The reaction was carried out at 350°C and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil, a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio), and a total space velocity of 0.5. The reactants were preheated at 100°C in a preheater before entering the fixed-bed reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 10.2%, total ethylbenzene and propylbenzene selectivity of 20.1%, and hydrogen selectivity of 5.3%.

[0062] Comparative Example 2: The magnesium loading in Example 1 was omitted. Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 480 were used as catalysts. The sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and the binder boehmite were mechanically mixed, with the mass ratio of ZSM-5 / ZSM-11 eutectic molecular sieves to boehmite being 7:3. The mixture was bonded and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0063] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 300g. The reaction was carried out at 350℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate, a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio), and a total mass hourly space velocity of 0.5. The reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, yielding the following results: carbon dioxide conversion rate of 15.8%, total ethylbenzene and propylbenzene selectivity of 12.5%, and hydrogen selectivity of 2.4%.

[0064] Comparative Example 3: The reaction temperature in Example 1 was adjusted to 500°C. Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve with a molar silicon-to-aluminum ratio of 480 was used as a catalyst. Magnesium nitrate with a magnesium loading of 24% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve and boehmite as a binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve to boehmite was 7:3. The mixture was bound and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0065] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 300g. At 500℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil and a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio) and a total mass hourly space velocity of 0.5, the reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 16.5%, total ethylbenzene and propylbenzene selectivity of 8.9%, and hydrogen selectivity of 4.5%.

[0066] Comparative Example 4: The sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve in Example 1 was replaced with a hydrogen-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve. A hydrogen-form nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve with a molar silicon-to-aluminum ratio of 480 was used as a catalyst. Magnesium nitrate with a magnesium loading of 24% was weighed and mechanically mixed with the hydrogen-form nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve and the binder boehmite. The mass ratio of the hydrogen-form nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve to the boehmite was 7:3. The mixture was bound and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0067] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 300g. The reaction was carried out at 350℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil, a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio), and a total mass hourly space velocity of 0.5. The reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, yielding the following results: carbon dioxide conversion rate of 15.8%, total ethylbenzene and propylbenzene selectivity of 16.3%, and hydrogen selectivity of 8.7%.

[0068] Comparative Example 5: The molar silica-alumina ratio of the sodium-type nanorod ZSM-5 / ZSM-11 eutectic molecular sieve in Example 1 was adjusted to 100. Sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves with a molar silicon-to-aluminum ratio of 100 were used as catalysts. Magnesium nitrate with a magnesium loading of 24% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves and boehmite as a binder. The mass ratio of sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieves to boehmite was 7:3. The mixture was bound and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0069] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 300g. At 350℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil and a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio) and a total mass hourly space velocity of 0.5, the reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 18.9%, total ethylbenzene and propylbenzene selectivity of 9.9%, and hydrogen selectivity of 1.9%.

[0070] Comparative Example 6: The sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve in Example 1 was modified to a sodium-type nanorod-shaped ZSM-5 molecular sieve. Sodium-type nanorod-shaped ZSM-5 molecular sieve with a molar silicon-to-aluminum ratio of 480 was used as a catalyst. Magnesium nitrate with a magnesium loading of 24% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-5 molecular sieve and boehmite binder, wherein the mass ratio of sodium-type nanorod-shaped ZSM-5 molecular sieve to boehmite was 7:3. The mixture was bonded and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0071] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 300g. The reaction was carried out at 350℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil, a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio), and a total mass hourly space velocity of 0.5. The reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, yielding the following results: carbon dioxide conversion rate of 12.2%, total ethylbenzene and propylbenzene selectivity of 11.4%, and hydrogen selectivity of 3.3%.

[0072] Comparative Example 7: The sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve in Example 1 was modified to a sodium-type nanorod-shaped ZSM-11 molecular sieve. Sodium-type nanorod-shaped ZSM-11 molecular sieve with a molar silica-alumina ratio of 480 was used as a catalyst. Magnesium nitrate with a magnesium loading of 24% was weighed and mechanically mixed with sodium-type nanorod-shaped ZSM-11 molecular sieve and boehmite binder, wherein the mass ratio of sodium-type nanorod-shaped ZSM-11 molecular sieve to boehmite was 7:3. The mixture was bonded and extruded into strips with a 2% dilute nitric acid solution, then dried at 100℃ for 16 h and calcined at 550℃ for 8 h to obtain the catalyst required for the reaction.

[0073] The prepared catalyst was loaded into a hypergravity reactor to form a hypergravity level of 300g. At 350℃ and atmospheric pressure, with the light hydrocarbons being reformate raffinate oil and a carbon dioxide:light hydrocarbon ratio of 2:8 (mass ratio) and a total mass hourly space velocity of 0.5, the reactants were preheated to 100℃ in a preheater before entering the hypergravity reactor for reaction. After 6 hours of reaction, the products were analyzed, and the reaction results were as follows: carbon dioxide conversion rate of 14.5%, total ethylbenzene and propylbenzene selectivity of 8.8%, and hydrogen selectivity of 1.5%.

[0074] Comparing Example 1 with Comparative Example 1, it can be found that the reaction under hypergravity conditions can greatly improve the carbon dioxide conversion rate, indicating that hypergravity conditions can promote the coupling of carbon dioxide reaction and light hydrocarbon dehydrogenation reaction, thereby greatly improving reaction efficiency and raw material conversion rate.

[0075] Comparing Example 1 with Comparative Example 2, it can be found that when the catalyst does not contain magnesium, the feed conversion rate is low, and the selectivity of the products ethylbenzene, propylbenzene and hydrogen is also low. This indicates that the introduction of magnesium changes the alkaline environment on the catalyst surface and improves the catalytic activity of the catalyst.

[0076] Comparing Example 1 with Comparative Example 3, it can be found that when the reaction temperature is 500℃, the increase in reaction temperature reduces the conversion rate of carbon dioxide in the reaction raw materials, while the selectivity of ethylbenzene, propylbenzene and hydrogen decreases. This indicates that a suitable reaction temperature is conducive to the conversion of carbon dioxide and the improvement of product selectivity.

[0077] Comparing Example 1 with Comparative Example 4, it can be found that when a hydrogen-type molecular sieve is used as the catalyst, the carbon dioxide conversion rate decreases, and the selectivity of ethylbenzene, propylbenzene, and hydrogen also decreases. This is because a weakly alkaline environment is suitable for the catalyst in which carbon dioxide reacts with light hydrocarbons to produce ethylbenzene and propylbenzene. The weakly alkaline sites are the main active sites of the reaction, indicating that the use of a sodium-type molecular sieve is crucial for improving the conversion rate and selectivity of the reaction.

[0078] Comparing Example 1 with Comparative Example 5, it can be found that when the molar silica-alumina ratio of the ZSM-5 / ZSM-11 eutectic molecular sieve is too small, the conversion rate of carbon dioxide in the raw material is low, and the selectivity of the products ethylbenzene, propylbenzene and hydrogen is also small, indicating that a suitable molecular sieve catalyst is conducive to the occurrence of the reaction.

[0079] Comparing Example 1 with Comparative Examples 6 and 7, it can be found that when the catalyst does not use ZSM-5 / ZSM-11 eutectic molecular sieve, the conversion rate of carbon dioxide in the feedstock is low, and the selectivity of the products ethylbenzene, propylbenzene and hydrogen is also low. This indicates that the unique pore structure and basic characteristics of the ZSM-5 / ZSM-11 eutectic molecular sieve catalyst promote the reaction of carbon dioxide with light hydrocarbons to produce ethylbenzene and propylbenzene.

Claims

1. A method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons, characterized in that, include: Using light hydrocarbons and carbon dioxide as raw materials, and magnesium-supported alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieves as catalysts, a catalytic reaction was carried out under the action of supergravity at a reaction temperature of 300~400℃ to obtain a liquid-phase product containing ethylbenzene and propylbenzene.

2. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 1, characterized in that, The hypergravity level is 200~500g.

3. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 1, characterized in that, The alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is an alkaline nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve.

4. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 3, characterized in that, The alkaline nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve is a sodium-type nanorod-shaped ZSM-5 / ZSM-11 eutectic molecular sieve.

5. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 1, characterized in that, The molar silica-alumina ratio of the alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is 300~600.

6. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 1, characterized in that, The preparation method of the magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is as follows: the alkaline ZSM-5 / ZSM-11 eutectic molecular sieve is mixed with a binder, a compound containing Mg is added, the mixture is mechanically mixed evenly, and then bound and extruded using a dilute nitric acid solution. After drying and calcination, the magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve is obtained.

7. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 6, characterized in that, The roasting temperature is 400~800 ℃, and the roasting time is 5~12 h.

8. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 1, characterized in that, In the magnesium-loaded alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve, the magnesium loading is 10% to 40% of the mass of the alkaline nano ZSM-5 / ZSM-11 eutectic molecular sieve.

9. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 1, characterized in that, The mass ratio of carbon dioxide to light hydrocarbons is 1:(0.4~9.5).

10. The method for producing ethylbenzene and propylbenzene by reacting carbon dioxide with light hydrocarbons according to claim 1, characterized in that, The light hydrocarbon is one or more of the following: reforming raffinate, reforming topping oil, pentane oil, n-butane, isobutane, n-pentane, isopentane, cyclopentane, n-hexane, cyclohexane, and isohexane.

Images