Ethylbenzene dehydrogenation catalyst, preparation method and application thereof

Abstract

The application discloses an ethylbenzene dehydrogenation catalyst and a preparation method and application thereof. The catalyst comprises, in percentage by mass based on the total mass of the catalyst, 55-68% of a carrier halloysite and 32-45% of an active component. The active component is a composite metal oxide, and the composite metal oxide comprises Fe2O3, K2O, CeO2, MoO3, ZrO2, BaO, Na2O and Sc2O3. The catalyst is applied to an ethylbenzene dehydrogenation reaction for preparing styrene, and has high catalytic activity, selectivity and good stability.

Description

Technical Field

[0001] This invention belongs to the field of dehydrogenation catalysis technology, specifically relating to an ethylbenzene dehydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Styrene is an important basic organic raw material, widely used in the synthesis of resins and rubber, as well as in pharmaceuticals, dyes, pesticides, and mineral processing. Its applications are extremely broad. In commercial applications, it is typically produced by catalytic dehydrogenation of ethylbenzene using a composite oxide catalyst at 600–700°C in the presence of a large amount of superheated steam. The catalytic dehydrogenation of ethylbenzene has always been the main technical route for styrene production, accounting for approximately 85% of total styrene production capacity. The most crucial core technology in the catalytic dehydrogenation of ethylbenzene to styrene method is the high-performance ethylbenzene dehydrogenation catalyst.

[0003] CN115138356A discloses a catalyst for the dehydrogenation of ethylbenzene to styrene, which uses high-temperature treated nanodiamond as the nanocarbon support and the noble metal Pd as the active component. This catalyst exhibits excellent catalytic activity. However, the high cost and susceptibility to poisoning of noble metal catalysts limit their further large-scale industrial application. Currently, Fe-K based composite oxide catalysts are the most widely used and have the best catalytic performance, attracting strong attention from researchers. The ethylbenzene dehydrogenation reaction is carried out under the catalysis of an iron-potassium-based oxide catalyst at high temperature and with excess water vapor. The addition of water vapor is mainly to provide and transfer heat and to eliminate carbon deposits generated during the reaction that lead to a decrease in catalyst activity. The disadvantage of this reaction process is its high energy consumption, and the large consumption of water resources contradicts the development concept of energy conservation and environmental protection. With the continuous increase in the demand for styrene in recent years, elements such as cerium, molybdenum, and manganese have been added to traditional iron-potassium oxide catalysts, which has improved the catalytic performance of ethylbenzene dehydrogenation catalysts to some extent.

[0004] The basic components of a catalyst for the dehydrogenation of ethylbenzene to styrene are the main catalyst, co-catalyst, pore-forming agent, and reinforcing agent. CN106582682A discloses a method for synthesizing Fe-K based oxide catalysts. CN108203365B, CN109569640A, and CN108097260A disclose methods for improving the catalytic performance, such as activity, selectivity, and stability, by adding other promoters. However, traditional Fe-K based oxide catalysts still have some problems, such as small specific surface area, uneven dispersion and low utilization of active sites, and unstable active sites. The methods used so far have not yielded significant benefits and cannot fully meet the various requirements of practical applications of catalysts for the dehydrogenation of ethylbenzene to styrene. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an ethylbenzene dehydrogenation catalyst, its preparation method, and its application. This catalyst features uniform dispersion of active components, good thermal stability, and a simple preparation process, making it suitable for large-scale industrial production. When applied to the ethylbenzene dehydrogenation reaction, this catalyst exhibits high catalytic activity, selectivity, and good stability.

[0006] The first aspect of the present invention provides an ethylbenzene dehydrogenation catalyst, which, based on the total mass of the catalyst and calculated by mass fraction, comprises: 55% to 68% halloysite support; 32% to 45% active component; wherein the active component is a composite metal oxide.

[0007] According to the present invention, based on the total mass of the composite metal oxide, the composite metal oxide comprises the following components by mass fraction:

[0008] a. 59%–77% Fe2O3;

[0009] b. 8%–14.5% K₂O;

[0010] c. 4.8%–12.8% CeO2;

[0011] d. 0.7%–4.8% MoO3;

[0012] e. 2.6%–5.9% ZrO2;

[0013] f. 0.6%–1.8% BaO;

[0014] g.0.1%~1.2% Na2O.

[0015] h.0.8%~4% Sc2O3.

[0016] According to the present invention, preferably, the halloysite is halloysite modified by ball milling molten salt method.

[0017] According to the present invention, in the ethylbenzene dehydrogenation catalyst, halloysite is modified by ball milling molten salt method, and the tubular halloysite support is expanded into a sheet-like halloysite support with a rough surface rich in defects.

[0018] According to the present invention, halloysite appears as platy and tubular structures in TEM morphology images. In the TEM morphology images, based on the total area of ​​tubular and platy halloysite, the proportion of halloysite nanosheets is 58% or more, preferably 58% to 94%, and more preferably 58% to 92%.

[0019] A second aspect of the present invention provides a method for preparing the above-mentioned ethylbenzene dehydrogenation catalyst. The preparation method is an impregnation method, preferably a wet impregnation method. The method includes the steps of dispersing halloysite in an active component source, followed by drying and calcination to obtain the catalyst.

[0020] According to the present invention, preferably, the halloysite is halloysite modified by ball milling and molten salt method, that is, halloysite modified by ball milling and molten salt method. The ball milling and molten salt modification step includes the steps of mixing sodium salt and halloysite evenly, ball milling, calcining, washing, and drying; the sodium salt includes sodium nitrite and sodium bicarbonate.

[0021] According to the present invention, in the ball milling molten salt method, the mass ratio of sodium bicarbonate to sodium nitrite is 0.08 to 0.35. The mass ratio of sodium salt to halloysite is 5.6 to 7.8.

[0022] According to the present invention, in the ball milling molten salt method, the sodium salt further includes sodium phosphate. Preferably, the mass ratio of sodium phosphate to sodium nitrite is 0.01 to 0.60, more preferably 0.08 to 0.50.

[0023] According to the present invention, in the ball milling molten salt method, grinding balls with a diameter of 3-6 mm are used, preferably zirconia balls. The ball milling speed is 300-400 rpm, and the ball milling time is 60-90 min.

[0024] According to the present invention, in the ball milling molten salt method, the calcination atmosphere is air; and / or, the calcination temperature is 350–550°C; and / or, the calcination time is 2–5 h. The heating rate during the process of heating to the calcination temperature is 1–8°C / min.

[0025] According to the present invention, in the ball milling molten salt method, the washing liquid is preferably deionized water. Washing is continued until the filtrate is neutral to ensure complete removal of soluble salts from the sample. Washing to neutrality is essential after calcination. Preferably, the neutral pH range is 6.75–7.35.

[0026] According to the present invention, in the ball milling molten salt method, the drying temperature is 60-100°C; and / or the drying time is 8-15 hours.

[0027] According to the present invention, in the preparation method of the ethylbenzene dehydrogenation catalyst, halloysite is redispersed in the active component source after water is added. Preferably, the solid-liquid ratio of the active component source to the added water is 1 g / 3 to 9 mL.

[0028] According to the present invention, in the method for preparing the ethylbenzene dehydrogenation catalyst, the mixture obtained after dispersing halloysite in the active component source is subjected to water evaporation. The evaporation is preferably carried out in a rotary evaporator; more preferably, the evaporation temperature is 45–60°C; and the evaporation time is 45–120 min.

[0029] According to the present invention, in the method for preparing the ethylbenzene dehydrogenation catalyst, the drying temperature is 60-100°C; and / or the drying time is 8-12 h.

[0030] According to the present invention, in the preparation method of the ethylbenzene dehydrogenation catalyst, the calcination atmosphere is air; and / or, the calcination temperature is 500–800°C; and / or, the calcination time is 2–5 h; and / or, the heating rate during the process of heating to the calcination temperature is 1–5°C / min. After reaching the calcination temperature, a certain calcination time is maintained.

[0031] According to the present invention, in the preparation method of the ethylbenzene dehydrogenation catalyst, the active component source includes Fe source, K source, Ce source, Mo source, Zr source, Ba source, Na source and Sc source.

[0032] According to the present invention, in the method for preparing the ethylbenzene dehydrogenation catalyst, the Fe source includes one or more of ferric oxide, ferric chloride, ferric acetate, ferric nitrate, and ferric sulfate; and / or, the K source includes any one or more of potassium carbonate, potassium bicarbonate, potassium nitrate, potassium chloride, and potassium sulfate; and / or, the Ce source includes one or more of cerium carbonate, cerium oxalate, cerium nitrate, cerium acetate, cerium chloride, and cerium sulfate; and / or, the Mo source includes one or two of ammonium molybdate and phosphomolybdic acid; and / or, the Zr source includes one or more of zirconium carbonate, zirconium acetate, zirconium nitrate, zirconium oxalate, or zirconium oxychloride; and / or, the Ba source includes one or more of barium oxide, barium carbonate, barium nitrate, barium sulfate, barium chloride, and barium hydroxide; and / or, the Na source includes one or two of sodium carbonate and sodium bicarbonate. The Sc source is an oxide of Sc and / or a salt of Sc. The Sc source includes one or more of scandium oxide, scandium chloride, scandium oxalate, and scandium acetate.

[0033] According to the present invention, the catalyst prepared by the above method is a powder, which can be further processed by extrusion molding into a monolithic structured catalyst for industrial application in the dehydrogenation of ethylbenzene to styrene. Preferably, the molded catalyst is a particle with a diameter of 2-5 mm and a length of 3-10 mm. Moisture can be added or evaporated as needed during the molding process. After molding, it can be dried at a temperature of 60-180°C; and / or for a drying time of 8-20 h.

[0034] The third aspect of the present invention provides the application of the above-described ethylbenzene dehydrogenation catalyst or the catalyst prepared by the above-described preparation method in the ethylbenzene dehydrogenation to styrene reaction.

[0035] According to the present invention, the application uses ethylbenzene as a raw material, and styrene is obtained after the raw material is reacted with an ethylbenzene dehydrogenation catalyst.

[0036] According to the present invention, the application conditions are: reaction pressure of 20–100 kPa; and ethylbenzene mass hourly space velocity of 0.2–2.0 h⁻¹. -1 The reaction temperature is 580–640℃; the water ratio (wt) is 1.0–2.0.

[0037] Compared with the prior art, the advantages of this invention are as follows:

[0038] (1) The catalyst of this invention comprises, based on the total mass of the catalyst, and calculated by mass fraction, 55%–68% halloysite support; 32%–45% active component; the active component is a composite metal oxide; the composite metal oxide includes Fe2O3, K2O, CeO2, MoO3, ZrO2, BaO, Na2O, and Sc2O3. The catalyst is a supported catalyst, and compared to traditional mechanically mixed catalysts, the dispersion of the metal oxide active component is more uniform and better, resulting in relatively small nanoparticles. In the reaction of ethylbenzene dehydrogenation to styrene, the number of accessible active sites of the catalyst is significantly increased, and the utilization rate of the metal oxide component is greatly improved. The catalyst composition of this invention includes Sc element. Sc element has a synergistic effect with the Al sites of halloysite, which can promote adsorption on the surface of reactants and improve the catalytic performance of the ethylbenzene dehydrogenation catalyst.

[0039] In this invention, the halloysite support treated by ball milling molten salt method is used, particularly by co-modification with sodium nitrite, sodium bicarbonate, and sodium phosphate, to prepare a supported catalyst through ball milling. The halloysite support modified by ball milling molten salt transforms from a tubular structure into a sheet-like structure with a rough surface rich in defect sites. When applied to the dehydrogenation of ethylbenzene to styrene, it exhibits high catalytic activity, selectivity, and good stability.

[0040] The catalyst of this invention uses natural tubular halloysite as the catalyst support material, which is inexpensive, readily available, and abundant. Furthermore, the supported catalyst reduces the amount of metal oxide active component used, thus lowering the production cost of the ethylbenzene dehydrogenation to styrene catalyst. This catalyst also exhibits high catalytic activity and selectivity, good stability, and a relatively simple and stable preparation process, making it suitable for large-scale application in the ethylbenzene dehydrogenation to styrene reaction.

[0041] (2) In the preparation method of the catalyst of the present invention, halloysite is used as a support, and halloysite is modified by ball milling molten salt method, preferably by sodium nitrite, sodium bicarbonate and sodium phosphate. The supported catalyst is prepared by ball milling. The halloysite support modified by ball milling and melting expands from a tubular shape to a sheet structure, with a rough surface and rich in defect sites. At the same time, the Sc element has a synergistic effect with the Al sites of halloysite, which can promote the adsorption of reactants on the surface and improve the catalytic performance of the ethylbenzene dehydrogenation catalyst.

[0042] (3) In the application of the present invention, the catalyst is suitable for the dehydrogenation of ethylbenzene to styrene reaction, and has the advantages of high catalytic activity, high selectivity and good stability. Attached Figure Description

[0043] Figure 1 This is a TEM image of the ethylbenzene dehydrogenation catalyst obtained in Example 1 of the present invention.

[0044] Figure 2 This is a TEM image of the ethylbenzene dehydrogenation catalyst obtained in Comparative Example 1 of this invention. Detailed Implementation

[0045] To illustrate the invention more clearly, the following embodiments are provided, but the scope of the invention is not limited to the embodiments.

[0046] The catalyst prepared by the above method was evaluated for activity in an isothermal fixed bed. For the activity evaluation of the catalyst for the dehydrogenation of ethylbenzene to styrene, the process is briefly described as follows:

[0047] Deionized water and ethylbenzene were separately metered into a preheating mixer, preheated and mixed into a gaseous state, and then entered the reactor. The reactor was heated by an electric heating wire to reach the set temperature. The reactor was a stainless steel tube, filled with 100 mL of catalyst. The reactants flowing out of the reactor were condensed in water and their composition was analyzed by gas chromatography.

[0048] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0049]

[0050]

[0051] In this invention, the TEM testing instrument used in each example is the JEOL JEM-200CX from Japan. Based on the total area of ​​tubular and platy halloysite, the proportion of halloysite nanosheets to the total halloysite is obtained through statistical calculation of the TEM morphology and geometric characteristics of the catalyst samples; this proportion represents the observed halloysite nanosheets to the total halloysite. The total halloysite is the sum of halloysite nanotubes and halloysite nanosheets.

[0052] The composition of the ethylbenzene dehydrogenation catalysts in each example and the evaluation results after 100 h of reaction are shown in Table 1. The stability evaluation results of the ethylbenzene dehydrogenation catalysts in Examples 1, 3, 10 and Comparative Examples 1, 3 are shown in Table 2.

[0053] Example 1

[0054] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.1g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0055] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0056] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite modified by ball milling as a support was obtained. TEM images of the catalyst are shown below. Figure 1 Halloysite nanosheets account for 90% of the total halloysite.

[0057] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0058] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.3 (wt). The test results after 100 h of reaction are shown in Table 1. The catalyst stability evaluation results are shown in Table 2.

[0059] Example 2

[0060] 5g of sodium nitrite, 2.85g of sodium phosphate, and 1.6g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.4g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0061] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0062] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 62% of the total halloysite.

[0063] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0064] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0065] Example 3

[0066] 5g of sodium nitrite, 0.25g of sodium phosphate, and 0.5g of sodium bicarbonate were weighed and ground in a mortar. Then, 0.85g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a ball diameter of 5mm and a milling speed of 350 rpm. The powder mixture was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0067] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0068] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 65% of the total halloysite.

[0069] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0070] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.3 (wt). The test results after 100 h of reaction are shown in Table 1. The catalyst stability evaluation results are shown in Table 2.

[0071] Example 4

[0072] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1.5g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.2g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0073] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0074] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 73% of the total halloysite.

[0075] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0076] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0077] Example 5

[0078] 5g of sodium nitrite, 2.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.25g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a ball diameter of 5mm and a milling speed of 350 rpm. The powder mixture was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0079] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0080] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 78% of the total halloysite.

[0081] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0082] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0083] Example 6

[0084] 5g of sodium nitrite, 1.5g of sodium phosphate, and 0.5g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.05g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a ball diameter of 5mm and a milling speed of 350 rpm. The powder mixture was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0085] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0086] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 83% of the total halloysite.

[0087] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0088] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0089] Example 7

[0090] 5g of sodium nitrite, 0.4g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 0.95g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a ball diameter of 5mm and a milling speed of 350 rpm. The powder mixture was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0091] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0092] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 80% of the total halloysite.

[0093] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0094] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0095] Example 8

[0096] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The powder mixture was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0097] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0098] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 88% of the total halloysite.

[0099] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0100] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0101] Example 9

[0102] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.3g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0103] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0104] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 81% of the total halloysite.

[0105] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0106] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0107] Example 10

[0108] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.1g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0109] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 9.1 parts CeO₂), ammonium molybdate (equivalent to 3.4 parts MoO₃), zirconium nitrate (equivalent to 4.9 parts ZrO₂), barium hydroxide (equivalent to 1.5 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 1 part Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0110] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 89% of the total halloysite.

[0111] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0112] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.3 (wt). The test results after 100 h of reaction are shown in Table 1. The catalyst stability evaluation results are shown in Table 2.

[0113] Example 11

[0114] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.1g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0115] Weigh out the following amounts: ferric oxide (equivalent to 60.8 parts Fe₂O₃), potassium carbonate (equivalent to 13.7 parts K₂O), cerium oxalate (equivalent to 11.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 5.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 3.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0116] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 90% of the total halloysite.

[0117] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0118] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0119] Example 12

[0120] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.1g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0121] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0122] 200 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 89% of the total halloysite.

[0123] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0124] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0125] Comparative Example 1

[0126] 5g of sodium nitrite, 3.2g of sodium phosphate, and 0.35g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.55g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0127] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0128] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite modified by ball milling as a support was obtained. TEM images of the catalyst are shown below. Figure 2 Halloysite nanosheets account for 52% of the total halloysite.

[0129] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0130] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.3 (wt). The test results after 100 h of reaction are shown in Table 1. The catalyst stability evaluation results are shown in Table 2.

[0131] Comparative Example 2

[0132] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.1g of halloysite was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified halloysite.

[0133] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 12.7 parts K₂O), cerium oxalate (equivalent to 9.3 parts CeO₂), ammonium molybdate (equivalent to 3.4 parts MoO₃), zirconium nitrate (equivalent to 4.9 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), and sodium carbonate (equivalent to 0.6 parts Na₂O). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0134] 160 parts of the modified halloysite were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst using halloysite modified by ball milling as a support was obtained. Halloysite nanosheets accounted for 89% of the total halloysite.

[0135] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0136] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of reaction temperature 620℃ and water ratio 1.3 (wt). The test results after 100 h of reaction are shown in Table 1.

[0137] Comparative Example 3

[0138] 5g of sodium nitrite, 1.5g of sodium phosphate, and 1g of sodium bicarbonate were weighed and ground in a mortar. Then, 1.1g of silica was added, and the four substances were mixed thoroughly. The mixture was then ball-milled for 75 minutes at a milling ball diameter of 5mm and a milling speed of 350 rpm. The resulting powder was then calcined in air at 400℃ for 2.5 hours at a heating rate of 5℃ / min. After cooling to room temperature (20℃), the solid sample was repeatedly washed with deionized water until the filtrate was neutral. The washed sample was then dried in an oven at 80℃ for 12 hours to obtain modified silica.

[0139] Weigh out the following amounts: ferric oxide (equivalent to 67.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.7 parts K₂O), cerium oxalate (equivalent to 8.6 parts CeO₂), ammonium molybdate (equivalent to 2.9 parts MoO₃), zirconium nitrate (equivalent to 4.4 parts ZrO₂), barium hydroxide (equivalent to 1.3 parts BaO), sodium carbonate (equivalent to 0.6 parts Na₂O), and scandium acetate (equivalent to 2.7 parts Sc₂O₃). Disperse these amounts in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio (solid (active component source) to water) is 1 g / 6 mL.

[0140] 160 parts of the modified silica were dispersed in the mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 80 min. The sample was then dried in an oven at 80 °C for 10 h. The dried sample was ground and then calcined in air at 650 °C for 3 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with ball-milled modified silica as a support was obtained.

[0141] After adjusting the water content of the powdered catalyst, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then dried in an oven at 80°C for 4 hours and in an oven at 150°C for 8 hours to obtain a monolithic, well-structured finished catalyst.

[0142] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and a mass hourly space velocity (WHSV) of 1.0 h⁻¹ for ethylbenzene. -1 The performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.3 (wt). The test results after 100 h of reaction are shown in Table 1. The catalyst stability evaluation results are shown in Table 2.

[0143] Table 1. Composition of ethylbenzene dehydrogenation catalysts and evaluation results after 100 h of reaction in the examples and comparative examples.

[0144]

[0145] Table 2. Stability evaluation results of ethylbenzene dehydrogenation catalysts in the examples and comparative examples.

[0146]

[0147]

[0148] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An ethylbenzene dehydrogenation catalyst, based on the total mass of the catalyst and calculated as a mass fraction, the catalyst comprises: 55%~68% of the carrier is halloysite; 32%~45% active ingredients; The active component is a composite metal oxide; Based on the total mass of the composite metal oxide, and calculated by mass fraction, the composite metal oxide comprises the following components: a. 59%~77% Fe2O3; b. 8%~14.5% K2O; c. 4.8%~12.8% CeO2; d. 0.7%~4.8% MoO3; e. 2.6%~5.9% ZrO2; f. 0.6%~1.8% BaO; g. 0.1%~1.2% Na2O; h. 0.8%~4% Sc2O3; In the halloysite carrier, based on the total area of ​​tubular halloysite and platy halloysite, halloysite nanosheets account for more than 58%.

2. The catalyst according to claim 1, characterized in that, In the halloysite carrier, based on the total area of ​​tubular halloysite and sheet halloysite, halloysite nanosheets account for 58% to 94%.

3. The catalyst according to claim 1 or 2, characterized in that, The halloysite is halloysite modified by ball milling molten salt method.

4. A method for preparing the catalyst according to any one of claims 1 to 3, the method comprising the steps of dispersing halloysite in an active component source, and then drying and calcining to obtain the catalyst; in, The sources of active components include Fe, K, Ce, Mo, Zr, Ba, Na, and Sc.

5. The preparation method according to claim 4, characterized in that, The halloysite is halloysite modified by ball milling molten salt method; the ball milling molten salt method modification steps include mixing sodium salt and halloysite evenly, ball milling, calcining, washing, and drying. The sodium salts include sodium nitrite and sodium bicarbonate.

6. The preparation method according to claim 5, characterized in that, The sodium salt also includes sodium phosphate.

7. The preparation method according to claim 5 or 6, characterized in that, The mass ratio of sodium bicarbonate to sodium nitrite is 0.08~0.35; And / or, the mass ratio of sodium salt to halloysite is 5.6 to 7.

8.

8. The preparation method according to claim 6, characterized in that, The mass ratio of sodium phosphate to sodium nitrite is 0.01 to 0.

60.

9. The preparation method according to claim 6, characterized in that, The mass ratio of sodium phosphate to sodium nitrite is 0.08~0.

50.

10. The preparation method according to claim 5, characterized in that, The ball mill uses grinding balls with a diameter of 3-6 mm; and / or, the ball milling speed is 300-400 rpm; and / or, the ball milling time is 60-90 min.

11. The preparation method according to claim 5, characterized in that, In the ball milling molten salt modification step, the calcination atmosphere is air; and / or, the calcination temperature is 350~550 ℃; and / or, the calcination time is 2~5 h.

12. The preparation method according to claim 4, characterized in that, The Fe source includes one or more of ferric oxide, ferric chloride, ferric acetate, ferric nitrate, and ferric sulfate; And / or, the K source includes any one or more of potassium carbonate, potassium bicarbonate, potassium nitrate, potassium chloride, and potassium sulfate; And / or, the Ce source includes one or more of cerium carbonate, cerium oxalate, cerium nitrate, cerium acetate, cerium chloride, and cerium sulfate; And / or, the Mo source includes one or both of ammonium molybdate and phosphomolybdic acid; And / or, the Zr source includes one or more of zirconium carbonate, zirconium acetate, zirconium nitrate, zirconium oxalate, or zirconium oxychloride; And / or, the Ba source includes one or more of barium oxide, barium carbonate, barium nitrate, barium sulfate, barium chloride, and barium hydroxide; And / or, the Na source includes one or both of sodium carbonate and sodium bicarbonate; And / or, the Sc source includes one or more of scandium oxide, scandium chloride, scandium oxalate, and scandium acetate.

13. The preparation method according to claim 4, characterized in that, The roasting atmosphere is an air atmosphere; And / or, the calcination temperature is 500~800℃; And / or, the calcination time is 2-5 hours; And / or, the heating rate during the process of heating to the calcination temperature is 1~5℃ / min.

14. The use of a catalyst according to any one of claims 1 to 3 or a catalyst prepared by any one of claims 4 to 13 in the dehydrogenation of ethylbenzene to styrene reaction.

Images