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 an active component of a composite metal oxide and a carrier of an epihalloysite. Preferably, the carrier content is 52% to 90% and the active component content is 10% to 48% based on the weight of the catalyst. The catalyst has the characteristics of uniform dispersion of the active component, good thermal stability and simple preparation process, and is suitable for large-scale industrial production. The catalyst has high catalytic activity, selectivity and good stability when applied to ethylbenzene dehydrogenation reaction.

Description

Technical Field

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

[0002] Styrene is the simplest and most important chemical raw material among unsaturated aromatic hydrocarbons, widely used in the synthesis of resins and rubber. In commercial applications, it is generally 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 key to the catalytic dehydrogenation of ethylbenzene is a high-performance catalyst for styrene production.

[0003] The basic components of catalysts for the dehydrogenation of ethylbenzene to styrene include the main catalyst, co-catalyst, pore-forming agent, and reinforcing agent. Currently, Fe-K based composite oxide catalysts are the most widely used and exhibit the best catalytic performance, attracting significant attention from researchers. Decades ago, catalysts with Fe-K-Cr as the main component became the mainstream catalysts for the dehydrogenation of ethylbenzene to styrene due to their excellent catalytic performance. In the 1980s, researchers successfully developed Fe-K-Ce-Mo based catalysts, in which Ce and Mo components replaced Cr components. This not only improved the catalyst's catalytic activity, selectivity, and stability but also avoided the environmental pollution caused by Cr oxides. CN112237919A, CN111054370A, and CN103537295B disclose the synthesis and preparation methods of such catalysts. 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.

[0004] The use of supported catalysts can solve the above problems to some extent. CN1704160A discloses a catalyst for ethylbenzene dehydrogenation. This patent employs a technical solution of supporting platinum and at least one selected from titanium, zirconium, and hafnium on a support. This catalyst is suitable for the industrial production of styrene from ethylbenzene dehydrogenation. CN1814347A discloses an ethylbenzene oxidative dehydrogenation catalyst, which uses titanium silicate molecular sieves as the support and active component, and vanadium, molybdenum, alkali metals, alkaline earth metals, VA, VIIIB, or rare earth elements as promoters. This catalyst has good activity and stability. However, the benefits of the methods to date are not significant and cannot fully meet the various requirements of practical applications of ethylbenzene dehydrogenation catalysts for styrene production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an ethylbenzene dehydrogenation catalyst, its preparation method, and its applications. 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, the catalyst comprising: halloysite as a support and a composite metal oxide as an active component.

[0007] According to the present invention, the support content is 52% to 90% based on the weight of the catalyst, and the active component content is 10% to 48%.

[0008] According to the present invention, preferably, the halloysite is a melt-modified halloysite.

[0009] According to the present invention, the dispersion of the composite metal oxide in the catalyst is 3.8% to 9.5%, preferably 4.6% to 9.5%. The dispersion is tested by chemisorption method, preferably static chemisorption method.

[0010] According to the present invention, based on the total mass of the composite metal oxide, the following components are included by mass fraction:

[0011] a. 55%–85% Fe2O3;

[0012] b. 5%–17% K₂O;

[0013] c. 5%–17% CeO2;

[0014] d. 1%–5% Co3O4;

[0015] e. 0.5% to 3% WO3 and / or MoO3;

[0016] f. 0.2% to 3% MgO and / or CaO;

[0017] g.0.1%~1.5% Na2O.

[0018] According to the present invention, based on the total mass of the composite metal oxide, the composite metal oxide further comprises 1% to 5% Nb₂O₅ by mass fraction. Nb₂O₅ and CeO₂ have a synergistic effect on the catalytic activity, selectivity, and stability of the ethylbenzene dehydrogenation catalyst.

[0019] A second aspect of this invention provides a method for preparing the above-mentioned ethylbenzene dehydrogenation catalyst. The preparation method is an impregnation method, specifically comprising 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 a melt-modified halloysite. The melt method includes the steps of mixing sodium salt and halloysite evenly, calcining, washing, and drying; the sodium salt includes sodium nitrate and sodium carbonate.

[0021] According to the present invention, in the melting method, the sodium salt further includes sodium nitrite. Preferably, the mass ratio of sodium nitrite to sodium nitrate is 0.005 to 0.5.

[0022] According to the present invention, in the melting method, the mass ratio of sodium carbonate to sodium nitrate is 0.05 to 0.2. The mass ratio of sodium salt to halloysite is 4.8 to 6.8.

[0023] According to the present invention, in the melting method, the calcination atmosphere is an air atmosphere; and / or, the calcination temperature is 350-600°C; and / or, the calcination time is 2-5 hours.

[0024] According to the present invention, in the melting 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 6.75–7.30. Different treatment methods or sodium salt dosages outside this range result in different surface physical structures and binding forces of halloysite as a support, leading to variations in the catalytic performance of the prepared catalyst.

[0025] According to the present invention, in the melting method, the drying temperature is 60-100°C; and / or the drying time is 8-15 hours.

[0026] 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.

[0027] According to the present invention, in the preparation method of the ethylbenzene dehydrogenation catalyst, the mixture obtained after dispersing halloysite in the active component source is subjected to water evaporation. 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. The temperature during rotary evaporation should not be too high or too low, and the evaporation rate should be moderate; otherwise, the dispersion of the active component on the support will be unsatisfactory, thereby affecting the catalytic performance.

[0028] 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.

[0029] 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. If the heating rate, calcination temperature, and calcination time exceed this range, it may cause sintering of the catalyst or changes in the crystal growth rate, thereby leading to the destruction of the catalyst structure and surface morphology, resulting in a sharp decrease in the specific surface area of ​​the catalyst, which is not conducive to maintaining good catalytic performance of the calcined catalyst.

[0030] 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, Co source, W source and / or Mo source, Mg source and / or Ca source and Na source.

[0031] 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 Co source includes one or more of cobalt nitrate, cobalt acetate, cobalt chloride, cobalt sulfate, and cobalt acetylacetonate; and / or, the W source includes one or more of ammonium tungstate, ammonium metatungstate, and phosphotungstic acid; and / or, the Mo source includes one or two of ammonium molybdate and phosphomolybdic acid; and / or, the Mg source includes one or more of magnesium oxide, magnesium carbonate, magnesium acetate, magnesium sulfate, and magnesium chloride; and / or, the Ca source includes one or more of calcium oxide, calcium carbonate, calcium acetate, calcium chloride, calcium sulfate, and calcium hydroxide; and / or, the Na source includes one or two of sodium carbonate and sodium bicarbonate. Different salts have different affinities for the treated halloysite support. Using other precursor salts can lead to an unsatisfactory binding degree between the active component and the support, resulting in a decrease in catalytic performance.

[0032] According to the present invention, in the method for preparing the ethylbenzene dehydrogenation catalyst, the active component source further includes a Nb source. The Nb source includes one or more of niobium nitrate, niobium carbonate, niobium oxalate, and niobium acetate.

[0033] According to the present invention, the catalyst prepared by the above method is a powder, which can be further processed into a monolithic structured catalyst by extrusion molding 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.

[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 570–640℃; the water ratio (wt) is 1.0–2.0.

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

[0038] 1. The catalyst of this invention comprises: halloysite as a support and a composite metal oxide as the active component; preferably, based on the weight of the catalyst, the support content is 52%–90%; and the active component content is 10%–48%. The catalyst is a supported catalyst, which, compared to traditional mixed catalysts, exhibits more uniform and better dispersion of the metal oxide active component, reducing the amount of active component used and thus lowering the production cost of the ethylbenzene dehydrogenation to styrene catalyst. Furthermore, the catalyst uses natural tubular halloysite as the catalyst support, which is inexpensive, readily available, and abundant. The tubular structure of halloysite primarily exposes Al-OH structures internally and Si-OH structures externally, exhibiting good stability and suitability for the ethylbenzene dehydrogenation to styrene reaction, thereby enhancing the catalytic performance of the catalyst.

[0039] In this invention, the use of halloysite support treated by the molten salt method, particularly the co-modification with sodium nitrate, sodium nitrite, and sodium carbonate, yields a one-dimensional tubular supported catalyst. The molten-modified halloysite support has a rough surface and exhibits an anchoring effect. Al-OH can anchor the main active sites such as Fe and K, resulting in relatively small nanoparticles. The tubular halloysite with its anchoring effect serves as the support, while the uniformly dispersed multi-component metal oxides on its surface act as reactive sites. This significantly increases the number of accessible active sites on the catalyst and greatly improves the utilization rate of the metal oxide components. It can increase the specific surface area of ​​the catalyst, enhance reactant mass transfer, and improve the catalyst's activity, stability, resistance to carbon deposition, and especially the ethylbenzene conversion rate.

[0040] 2. In the preparation method of the present invention, halloysite is used as a carrier, and halloysite is modified by melt method, preferably halloysite modified by sodium nitrate, sodium nitrite and sodium carbonate. The catalyst prepared has advantages such as high catalytic activity and good stability. Moreover, the preparation process is relatively simple and stable, and it can be applied on a large scale to the dehydrogenation of ethylbenzene to styrene reaction to improve the catalytic performance of the catalyst.

[0041] 3. In the application of this invention, the catalyst is suitable for the dehydrogenation of ethylbenzene to styrene reaction, and has advantages such as high catalytic activity and good stability in this reaction. Attached Figure Description

[0042] Figure 1 The image shows a TEM image of the catalyst prepared in Example 1.

[0043] Figure 2 The image shows a TEM image of the catalyst prepared in Example 10. Detailed Implementation

[0044] To illustrate the invention more clearly, the following embodiments are provided, but the scope of the invention is not limited to the embodiments.

[0045] In this invention, the active ingredient sources are measured in parts by weight in each example.

[0046] In this invention, the catalysts in each example are evaluated for activity in an isothermal fixed bed. The activity evaluation process for the ethylbenzene dehydrogenation to styrene catalyst is briefly described below:

[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 dispersion in each example was obtained by static chemisorption testing. Specifically, the dispersion was obtained by chemisorption testing using an Autosorb IQ instrument from Quanta Chrome, USA. First, the catalyst sample was purged at 300°C under a He atmosphere for 2 hours, with a heating rate of 10°C / min. After cooling to room temperature (20°C), H2 was introduced, and the temperature was raised to 850°C and held for half an hour to reduce the metal oxide. Finally, He was introduced again for purging, and the sample was cooled to 40°C. The amount of hydrogen adsorbed (unit: mmol / g, meaning the mass of hydrogen adsorbed on a unit mass of catalyst) was then measured by static chemisorption under normal pressure. The dispersion (atomic percentage) of the metal oxide was then obtained based on the amount of hydrogen adsorbed.

[0052] In this invention, the TEM testing instrument used in each example is the JEM-200CX from JEOL Corporation of Japan.

[0053] Example 1:

[0054] 4g of sodium nitrate, 1g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0055] Weigh out the following amounts: ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 1.2 parts MgO), and sodium carbonate (equivalent to 0.4 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.

[0056] 150 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 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. TEM images of the catalyst are shown below. Figure 1 The dispersion of the composite metal oxide in the catalyst is 7.9%.

[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 10 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 73.1%, and the styrene selectivity was 96.7%. The test results are shown in Table 1. The test results after 300 h of reaction are shown in Table 2.

[0059] Example 2:

[0060] 5g of sodium nitrate, 0.025g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0061] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 1.2 parts MgO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 150 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 4.8%.

[0062] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0063] 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 at a reaction temperature of 620℃ and a water ratio of 1.0 (wt).

[0064] After 100 hours of reaction, the conversion rate of ethylbenzene reached 72.2%, and the selectivity of styrene was 95.6%. The test results are shown in Table 1.

[0065] Example 3:

[0066] 5g of sodium nitrate, 0.5g of sodium nitrite, and 0.8g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0067] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 1.2 parts MgO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 150 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 6.5%.

[0068] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0069] 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 72.8%, and the styrene selectivity was 96.3%. The test results are shown in Table 1.

[0070] Example 4:

[0071] 4g of sodium nitrate, 1.84g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0072] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 1.2 parts MgO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 150 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 6.0%.

[0073] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0074] 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 72.6%, and the styrene selectivity was 96.2%. The test results are shown in Table 1.

[0075] Example 5:

[0076] 4g of sodium nitrate, 1g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0077] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), calcium carbonate (equivalent to 1.2 parts CaO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 150 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 7.7%.

[0078] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0079] 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 Performance evaluation was conducted at a reaction temperature of 620℃ and a water ratio of 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 72.9%, and the styrene selectivity was 96.6%. The test results are shown in Table 1. The test results after 300 h of reaction are shown in Table 2.

[0080] Example 6:

[0081] 4g of sodium nitrate, 1g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0082] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 7.8 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 1 part Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), calcium carbonate (equivalent to 1.2 parts CaO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 150 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 7.5%.

[0083] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0084] 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 72.5%, and the styrene selectivity was 96.0%. The test results are shown in Table 1.

[0085] Example 7:

[0086] 4g of sodium nitrate, 1g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0087] Ferric nitrate (equivalent to 70.2 parts Fe₂O₃), potassium carbonate (equivalent to 9.0 parts K₂O), cerium nitrate (equivalent to 5.8 parts CeO₂), cobalt nitrate (equivalent to 1.8 parts Co₃O₄), niobium nitrate (equivalent to 2.0 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 0.4 parts MgO), and sodium carbonate (equivalent to 0.2 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 210 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 8.2%.

[0088] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0089] 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 72.6%, and the styrene selectivity was 96.4%. The test results are shown in Table 1.

[0090] Example 8:

[0091] 4g of sodium nitrate, 1.6g of sodium nitrite, and 0.64g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0092] Ferric nitrate (equivalent to 70.2 parts Fe₂O₃), potassium carbonate (equivalent to 9.0 parts K₂O), cerium nitrate (equivalent to 5.8 parts CeO₂), cobalt nitrate (equivalent to 1.8 parts Co₃O₄), niobium nitrate (equivalent to 2.0 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 0.4 parts MgO), and sodium carbonate (equivalent to 0.2 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 210 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 8.0%.

[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 10 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 a reaction temperature of 620℃ and a water ratio of 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 72.5%, and the styrene selectivity was 96.3%. The test results are shown in Table 1. The test results after 300 h of reaction are shown in Table 2.

[0095] Example 9:

[0096] 4g of sodium nitrate, 1g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0097] Ferric nitrate (equivalent to 63.4 parts Fe₂O₃), potassium carbonate (equivalent to 7.2 parts K₂O), cerium nitrate (equivalent to 5.6 parts CeO₂), cobalt nitrate (equivalent to 1.5 parts Co₃O₄), niobium nitrate (equivalent to 1.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.5 parts MoO₃), magnesium acetate (equivalent to 0.3 parts MgO), and sodium carbonate (equivalent to 0.1 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 320 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 8.9%.

[0098] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0099] 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 72.1%, and the styrene selectivity was 95.8%. The test results are shown in Table 1.

[0100] Example 10:

[0101] 2.5 g of sodium nitrate, 0.025 g of sodium nitrite, and 0.6 g of sodium carbonate were weighed and ground in a mortar. Then, 1 g of halloysite was added and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350 °C for 2 h at a heating rate of 5 °C / min. After cooling to room temperature (20 °C), 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 °C for 10 h to obtain modified halloysite.

[0102] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 1.2 parts MgO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 150 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. The TEM image of the catalyst is shown below. Figure 2 The dispersion of the composite metal oxide in the catalyst is 3.9%.

[0103] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0104] 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 71.1%, and the styrene selectivity was 94.2%. The test results after 300 h of reaction are shown in Table 2.

[0105] Example 11:

[0106] 5g of sodium nitrate, 3.25g of sodium nitrite, and 0.375g of sodium carbonate were weighed and ground in a mortar. Then, 1g of halloysite was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified halloysite.

[0107] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), magnesium acetate (equivalent to 1.2 parts MgO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solid to the added water was 1 g / 6 mL. 150 parts of the modified halloysite were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with halloysite as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 4.1%.

[0108] 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 10 hours to obtain a monolithic, well-structured finished catalyst.

[0109] 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 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 71.3%, and the styrene selectivity was 94.4%. The test results are shown in Tables 1 and 2.

[0110] Example 12:

[0111] The difference from Example 1 is that sodium nitrite is not added in the preparation method of modified halloysite. Specifically, 4g of sodium nitrate and 0.3g of sodium carbonate are weighed and placed in a mortar for grinding. Then, 1g of halloysite is added and the grinding continues until the three substances are mixed evenly. The mixed powder is then calcined in air at 350°C for 2 hours at a heating rate of 5°C / min. After cooling to room temperature (20°C), the solid sample is repeatedly washed with deionized water until the filtrate is neutral. The washed sample is then dried in an oven at 80°C for 10 hours to obtain modified halloysite. The remaining steps are the same as in Example 1. The test results are shown in Tables 1 and 2. The dispersion of the composite metal oxide is 3.8%. The TEM test pattern of the catalyst is similar. Figure 2 .

[0112] Comparative Example 1:

[0113] 4g of sodium nitrate, 1g of sodium nitrite, and 0.3g of sodium carbonate were weighed and ground in a mortar. Then, 1g of silica was added, and the mixture was ground thoroughly until all four substances were homogeneous. The powder mixture was then calcined in air at 350℃ for 2 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 10 hours to obtain modified silica.

[0114] Ferric nitrate (equivalent to 74.8 parts Fe₂O₃), potassium carbonate (equivalent to 11.8 parts K₂O), cerium nitrate (equivalent to 6.4 parts CeO₂), cobalt nitrate (equivalent to 2.4 parts Co₃O₄), niobium nitrate (equivalent to 2.4 parts Nb₂O₅), ammonium molybdate (equivalent to 0.6 parts MoO₃), calcium carbonate (equivalent to 1.2 parts CaO), and sodium carbonate (equivalent to 0.4 parts Na₂O) were weighed and dispersed in an appropriate amount of water to prepare a mixed solution. The solid-liquid ratio of the solids to the added water was 1 g / 6 mL. 150 parts of modified silica were dispersed in the active component source mixture. After stirring for 30 min, the water in the solution was evaporated to dryness in a rotary evaporator at 50 °C for 60 min. The sample was then dried in an oven at 80 °C for 12 h. The dried sample was ground and then calcined in air at 550 °C for 2 h at a heating rate of 2 °C / min. A composite metal oxide catalyst with modified silica as the support was obtained. In the catalyst, the dispersion of the composite metal oxide is 3.3%.

[0115] The powdered catalyst was adjusted for water content, then 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 then at 150°C for 10 hours to obtain a monolithic, well-structured finished catalyst. 100 mL of the catalyst was loaded into a reactor at 70 kPa (absolute pressure) and an ethylbenzene mass hourly space velocity (MHSV) of 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 (wt). After 100 h of reaction, the ethylbenzene conversion rate reached 69.5%, and the styrene selectivity was 93.8%. The test results after 300 h of reaction are shown in Table 2.

[0116] Table 1. Composition, properties, and evaluation results of the dehydrogenation catalysts in the examples and comparative examples.

[0117]

[0118] *Comparative Example 1 uses silica as a catalyst support.

[0119] Table 2. Stability evaluation results of dehydrogenation catalysts in the examples and comparative examples.

[0120]

[0121] 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, characterized in that, The catalyst comprises: halloysite as a support and composite metal oxide as the active component; based on the weight of the catalyst, the support content is 52%~90%; and the active component content is 10%~48%. Based on the total mass of the composite metal oxides, and expressed as a mass fraction, it includes the following components: a. 55%~85% Fe2O3; b. 5%~17% K2O; c. 5%~17% CeO2; d. 1%~5% Co3O4; e. 0.5%~3% WO3 and / or MoO3; f. 0.2%~3% MgO and / or CaO; g. 0.1%~1.5% Na2O; h. 1%~5% Nb2O5.

2. The catalyst according to claim 1, characterized in that, In the catalyst, the dispersion of the composite metal oxide is 3.8% to 9.5%.

3. The catalyst according to claim 2, characterized in that, In the catalyst, the dispersion of the composite metal oxide is 4.6% to 9.5%.

4. A method for preparing the catalyst according to any one of claims 1 to 3, comprising: Halloysite was dispersed in the active component source, and then dried and calcined to obtain the catalyst.

5. The preparation method according to claim 4, characterized in that, The halloysite is a modified halloysite produced by the melting process.

6. The preparation method according to claim 5, characterized in that, The melting method includes the steps of mixing sodium salt and halloysite evenly, calcining, washing, and drying; the sodium salt includes sodium nitrate and sodium carbonate.

7. The preparation method according to claim 6, characterized in that, The sodium salts include sodium nitrate, sodium carbonate, and sodium nitrite.

8. The preparation method according to claim 7, characterized in that, The mass ratio of sodium nitrite to sodium nitrate is 0.005~0.

5.

9. The preparation method according to any one of claims 6 to 8, characterized in that, The mass ratio of sodium carbonate to sodium nitrate is 0.05 to 0.2; and / or, the mass ratio of sodium salt to halloysite is 4.8 to 6.

8.

10. The preparation method according to claim 6, characterized in that, In the melting method, the calcination atmosphere is air; and / or, the calcination temperature is 350~600 ℃; and / or, the calcination time is 2~5 h.

11. The preparation method according to claim 6, characterized in that, In the melting method, the product is washed until neutral after calcination.

12. The preparation method according to claim 4, characterized in that, In the preparation method of the ethylbenzene dehydrogenation catalyst, the calcination atmosphere is air; and / or, the calcination temperature is 500~800℃; and / or, the calcination time is 2~5h; and / or, the heating rate during the process of heating to the calcination temperature is 1~5℃ / min.

13. The use of the catalyst according to any one of claims 1 to 3 or the catalyst prepared by the preparation method according to any one of claims 4 to 12 in the dehydrogenation of ethylbenzene to styrene reaction.

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