Dehydrogenation catalyst, preparation method therefor, and use thereof, and method for preparing styrene by dehydrogenation of ethylbenzene

Abstract

The present invention relates to the technical field of dehydrogenation catalysis, and specifically relates to a dehydrogenation catalyst, a preparation method therefor, and a use thereof, and a method for preparing styrene by dehydrogenation of ethylbenzene. The catalyst comprises the following components based on the total weight of the catalyst: a cryptomelane oxide at a content of 4.2 wt％ to 8.5 wt％; Fe2O3 at a content of 56 wt％ to 72 wt％; K2O at a content of 5.6 wt％ to 10 wt％; CeO2 at a content of 6 wt％ to 11 wt％; a group VIB metal oxide at a content of 2 wt% to 6.5 wt%; a group VIII metal oxide at a content of 2 wt% to 4.4 wt%; a group IIIB, IVB, and / or VB metal oxide at a content of 1.8 wt% to 3.2 wt%; and an alkaline earth metal oxide having a CaO content of 0.3 wt% to 1.2 wt%. The dehydrogenation catalyst of the present invention can be applied to a dehydrogenation reaction of an alkylbenzene (ethylbenzene) to produce an alkenylbenzene (such as styrene), and has the characteristics of high catalytic activity, good stability, and low deactivation.

Description

Dehydrogenation catalysts, their preparation methods and applications, and methods for the dehydrogenation of ethylbenzene to styrene. Technical Field

[0001] This invention relates to the field of dehydrogenation catalysis technology, specifically to a dehydrogenation catalyst, its preparation method and application, and a method for the dehydrogenation of ethylbenzene to styrene. Background Technology

[0002] Styrene is one of the simplest and most important chemical raw materials among unsaturated aromatic hydrocarbons, widely used in the synthesis of resins and rubber. These materials have crucial applications in industries such as automobile manufacturing, home appliances, textiles, building materials, light industry, and toys. Furthermore, styrene is used in pharmaceuticals, dyes, pesticides, and mineral processing, making its applications extremely broad. In commercial applications, styrene is typically produced by catalytic dehydrogenation of ethylbenzene at high temperatures using a composite oxide catalyst in the presence of a large amount of superheated steam. In the reaction, water plays a role in removing carbon deposits and providing heat, maintaining the high performance of the catalyst. The weight ratio of water to ethylbenzene in the reaction is defined as the "water ratio." A lower water ratio results in poorer catalyst performance. 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 the styrene-to-ethylbenzene dehydrogenation process.

[0003] Research on styrene catalysts began in the 1920s and has a history of over 70 years. Several important transformations and upgrades have occurred during the development of styrene catalysts: the replacement of Fe-K-Cr catalysts with Fe-K-Ce catalysts; the shift from high-K to low-K catalysts; the upgrade from high-water-ratio catalysts to low-water-ratio catalysts (i.e., catalysts that maintain performance under low-water-ratio conditions); and a significant increase in catalyst lifespan. In current industrial applications, the dehydrogenation of ethylbenzene to styrene is typically carried out in a fixed-bed reactor at 580–650°C. The catalysts used are usually potassium-doped Fe oxides and other promoters to stabilize the catalyst morphology or prevent deactivation.

[0004] In the actual dehydrogenation reaction of ethylbenzene to styrene, the potassium (K) in the Fe-K based catalyst is gradually lost, and the ferric species are gradually reduced to lower valence iron species. Combined with the accumulation of carbon on the catalyst surface, the catalyst deactivates. CN113710632A and CN101992129B disclose similar methods for maintaining the activity of ethylbenzene dehydrogenation catalysts. These methods involve mixing a steam stream and an ethylbenzene stream to form a feed mixture, which is then fed into a dehydrogenation reactor containing an alkali metal-promoted catalyst. A liquid selected from alkali metal liquids, alkali metal compound liquids, or liquid solutions containing alkali metals is injected into the feed stream (such as the steam stream, the ethylbenzene stream, or the ethylbenzene / steam feed mixture) to maintain catalyst activity.

[0005] However, in the catalytic reaction technology for the dehydrogenation of ethylbenzene to styrene, the current catalyst preparation methods have not yielded significant benefits. The catalytic activity and stability of the catalysts cannot fully meet the requirements of practical applications of ethylbenzene dehydrogenation to styrene catalysts. It is now necessary to improve the activity, stability and service life of catalysts through catalyst design and preparation methods. Summary of the Invention

[0006] To address the problems of low activity and poor stability in existing catalysts for the dehydrogenation of ethylbenzene to styrene, as well as catalyst deactivation due to severe potassium loss and reduction of ferric iron during dehydrogenation, this invention provides a dehydrogenation catalyst, its preparation method, its application, and a method for the dehydrogenation of ethylbenzene to styrene. This dehydrogenation catalyst, when applied to the dehydrogenation of alkylbenzenes (e.g., ethylbenzene) to alkenylbenzenes (e.g., styrene), exhibits high catalytic activity, good stability, and minimal deactivation.

[0007] To achieve the above objectives, a first aspect of the present invention provides a dehydrogenation catalyst comprising the following components based on the total weight of the catalyst:

[0008] Cryptomonoxide-type oxides, with a content of 4.2 wt%-8.5 wt%;

[0009] Fe2O3 content is 56.0wt%-72.0wt%;

[0010] K2O, with a content of 5.6wt%-10.0wt%;

[0011] CeO2 content is 6.0wt%-11.0wt%;

[0012] The content of the group VIB metal element oxide is 2.0wt%-6.5wt%, and the group VIB metal element oxide is preferably MoO3 and / or WO3, more preferably MoO3;

[0013] The oxides of Group VIII metal elements are present in a content of 2.0 wt% to 4.4 wt%, and the oxides of Group VIII metal elements are preferably Co3O4 and / or NiO, more preferably Co3O4;

[0014] The oxides of group IIIB, IVB and / or VB metal elements are present in a content of 1.8wt%-3.2wt%, wherein the oxides of group IIIB, IVB and / or VB metal elements are preferably selected from at least one of Sc2O3, Y2O3, V2O5, Nb2O5 or ZrO2, and more preferably ZrO2;

[0015] The alkaline earth metal oxide has a content of 0.3wt%-1.2wt%, and the alkaline earth metal oxide is preferably selected from at least one of BeO, MgO, CaO, SrO and BaO, more preferably MgO and / or CaO, and most preferably CaO.

[0016] A second aspect of the present invention provides a method for preparing the dehydrogenation catalyst of the present invention, the method comprising:

[0017] (1) Fe source, K source, Ce source, group VIB metal element source, group VIII metal element source, IIIB, IVB and / or group VB metal element source, alkaline earth metal source are mixed in the corresponding proportions and the precursor is obtained by first calcination.

[0018] (2) The precursor is mixed with crypto-potassium manganese oxide, molded and dried to obtain a dehydrogenation catalyst.

[0019] A third aspect of this invention provides the use of cryptomonas oxide for preparing a dehydrogenation catalyst. The dehydrogenation catalyst can be used for the dehydrogenation of alkylbenzenes to prepare alkenylbenzenes. During the reaction, potassium (K) in the pores of the cryptomonas oxide migrates and is slowly released, thus replenishing the catalyst with potassium. The released K combines with iron oxides to form potassium polyferrate, preventing a decrease in catalyst performance.

[0020] A fourth aspect of this invention provides the application of the dehydrogenation catalyst described herein in the dehydrogenation of alkylbenzenes to prepare alkenylbenzenes. The alkylbenzenes include, but are not limited to, ethylbenzene, methyl ethylbenzene, diethylbenzene, and cumene. The dehydrogenation catalyst of this invention can also be potentially and effectively used in the dehydrogenation reactions of a wider variety of aromatic hydrocarbons.

[0021] The fifth aspect of this invention provides a method for the dehydrogenation of ethylbenzene to produce styrene, the method comprising:

[0022] In the presence of a catalyst, ethylbenzene and water are contacted to carry out a dehydrogenation reaction; the catalyst includes the dehydrogenation catalyst described in this invention.

[0023] Compared with the prior art, the technical advantages of the present invention through the above technical solution are as follows:

[0024] (1) The dehydrogenation catalyst contains crypto-potassium manganese oxide. During the dehydrogenation of ethylbenzene to styrene, the K in the pores of the crypto-potassium manganese oxide will migrate and be slowly released, thus playing a role in replenishing K in the catalyst. The released K will combine with iron oxide to form potassium polyferrate, preventing the catalyst performance from deteriorating.

[0025] (2) The slow release of K in the pores of crypto-potassium manganese oxide can maintain the stability of the main active phase potassium polyferrate crystal structure during the reaction process, delay the reduction of ferric species, and still provide sufficient catalytic performance during long-term catalytic operation, so that the catalyst has high stability.

[0026] (3) After the K in the channels of the crypto-potassium manganese oxide is gradually released, the Mn and Ti elements in the oxide crystal structure will gradually become high-valence species, continue to contribute to the redox cycle of the dehydrogenation of ethylbenzene to styrene, thereby improving the catalytic activity of the catalyst.

[0027] (4) The crypto-KMnO type oxide was prepared by solid-phase molten salt method, with a microstructure of nanoparticles, and was doped with Ti. This method can maintain a specific range of crystal facet ratios for the crypto-KMnO type oxide crystals, and the specific crystal facets help to improve the catalytic performance of the catalyst.

[0028] (5) The dehydrogenation catalyst of the present invention is used in the dehydrogenation of alkylbenzene (e.g., ethylbenzene) to alkenylbenzene (e.g., styrene). It has the characteristics of high catalytic activity, good stability, adaptability to low water ratio and simple preparation process, and is suitable for large-scale industrial production. Attached Figure Description

[0029] Figure 1 is the XRD pattern of the crypto-potassium manganese oxide obtained in Example 1 of the present invention;

[0030] Figure 2 is a SEM image of the crypto-potassium manganese oxide obtained in Example 1 of the present invention;

[0031] Figure 3 is the XRD pattern of the catalyst obtained in Example 1 of the present invention;

[0032] Figure 4 is a SEM-EDS electron microscope image of the catalyst obtained in Example 1 of the present invention;

[0033] Figure 5 is a STEM-EDS electron microscope image of the catalyst obtained in Example 1 of the present invention;

[0034] Figure 6 is the Fe 2p spectrum of XPS of the catalyst obtained in Example 1 of the present invention;

[0035] Figure 7 shows the XRD pattern of the catalyst obtained in Comparative Example 1;

[0036] Figure 8 shows the Fe 2p spectrum of the XPS of the catalyst obtained in Comparative Example 1. Detailed Implementation

[0037] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0038] A first aspect of the present invention provides a dehydrogenation catalyst, said catalyst comprising the following components based on the total weight of the catalyst:

[0039] Cryptomonoxide-type oxides, with a content of 4.2 wt%-8.5 wt%;

[0040] Fe2O3 content is 56.0wt%-72.0wt%;

[0041] K2O, with a content of 5.6wt%-10.0wt%;

[0042] CeO2 content is 6.0wt%-11.0wt%;

[0043] The content of the group VIB metal element oxide is 2.0wt%-6.5wt%, and the group VIB metal element oxide is preferably MoO3 and / or WO3, more preferably MoO3;

[0044] The oxides of Group VIII metal elements are present in a content of 2.0 wt% to 4.4 wt%, and the oxides of Group VIII metal elements are preferably Co3O4 and / or NiO, more preferably Co3O4;

[0045] The oxides of group IIIB, IVB and / or VB metal elements are present in a content of 1.8wt%-3.2wt%, wherein the oxides of group IIIB, IVB and / or VB metal elements are preferably selected from at least one of Sc2O3, Y2O3, V2O5, Nb2O5 or ZrO2, and more preferably ZrO2;

[0046] The alkaline earth metal oxide has a content of 0.3wt%-1.2wt%, and the alkaline earth metal oxide is preferably selected from at least one of BeO, MgO, CaO, SrO and BaO, more preferably MgO and / or CaO, and most preferably CaO.

[0047] The dehydrogenation catalyst of this invention contains crypto-potassium manganese oxide. During the dehydrogenation to styrene reaction, potassium (K) in the pores of the crypto-potassium manganese oxide migrates and is slowly released, thereby replenishing the catalyst with potassium. The released potassium combines with iron oxide to form potassium polyferrate, preventing the catalyst performance from deteriorating.

[0048] After the K in the channels of the crypto-potassium manganese oxide is gradually released, the Mn and Ti elements in the oxide crystal structure will gradually become high-valence species, continue to contribute to the redox cycle of the dehydrogenation of ethylbenzene to styrene, and thus enhance the catalytic activity of the catalyst.

[0049] In this invention, the content of each component in the catalyst is calculated by ICP testing; wherein, the K2O content does not include the potassium content in crypto-potassium manganese oxide.

[0050] Cryptomanganese oxides are nanoparticles with a particle size of 30-90 nm, preferably 40-80 nm. The particle size of the cryptomanganese oxide nanoparticles is related to the calcination process in the preparation method. Shortening the calcination time and decreasing the heating rate will reduce the particle size of the cryptomanganese oxide nanoparticles; conversely, extending the calcination time, increasing the calcination temperature, and increasing the heating rate will increase the particle size of the cryptomanganese oxide nanoparticles.

[0051] According to a preferred embodiment of the present invention, the X-ray diffraction pattern of the dehydrogenation catalyst contains characteristic diffraction peaks of crypto-potassium manganese oxide; preferably, the XRD pattern of the dehydrogenation catalyst has at least one diffraction peak at 2θ of 12.763±0.30°, 18.126±0.30°, 50.077±0.30°, and 60.268±0.30°.

[0052] Cryptomonoxide oxides were prepared using a solid-phase molten salt method, exhibiting a nanoparticle microstructure and doped with Ti. This method allows the cryptomonoxide oxide crystals to maintain a specific range of crystal facet ratios, which helps to improve the catalytic performance of the catalyst.

[0053] According to a preferred embodiment of the present invention, the content of crypto-potassium manganese oxide is 5.4 wt%-7.6 wt%.

[0054] In this invention, the range of selectable proportions of ferric iron in the Fe 2p peaks of the XPS spectrum of the dehydrogenation catalyst is relatively wide. Preferably, the proportion of ferric iron in the Fe 2p peaks is greater than 48%. According to a preferred embodiment of this invention, the proportion of ferric iron in the Fe 2p peaks of the XPS spectrum of the dehydrogenation catalyst is greater than 54%.

[0055] In this invention, the surface trivalent iron content ratio of the dehydrogenation catalyst was analyzed by X-ray photoelectron spectroscopy (XPS). The method used a PHI-5000C ESCA photoelectron spectrometer (USA) with Mg Kα rays as the excitation source. The obtained X-ray photoelectron spectrum was calibrated using a C1s spectrum at 284.6 eV, and peak separation and other data processing were performed using XPS Peak 41 software.

[0056] In this invention, the dehydrogenation catalyst contains potassium polyferrate crystals; the slow-release effect of K in the pores of the crypto-potassium manganese oxide can maintain the stability of the main active phase potassium polyferrate crystal structure during the reaction process, delay the reduction of ferric species, and still provide sufficiently good catalytic performance during long-term catalytic operation, thus giving the catalyst high stability.

[0057] According to a preferred embodiment of the present invention, the K content in the crypto-potassium manganese oxide is 6.4 wt% to 6.8 wt%.

[0058] According to a preferred embodiment of the present invention, the crypto-potassium manganese oxide is a Ti-doped crypto-potassium manganese oxide.

[0059] According to a preferred embodiment of the present invention, the crypto-potassium manganese oxide is a titanium-doped crypto-potassium manganese oxide, preferably, the molar ratio of Mn to Ti is 1:1.9-4.5.

[0060] According to a preferred embodiment of the present invention, the crypto-potassium manganese oxide comprises the X-ray diffraction pattern shown below. a: ±0.30°, b: varies with 2θ.

[0061] In this invention, in the X-ray diffraction pattern, vw, w, m, s, and vs represent the diffraction peak intensities, where vw is very weak, w is weak, m is moderate, s is strong, and vs is very strong. Generally, vw is less than 5%, w is 5%-20% (inclusive), m is 20%-40% (inclusive), s is 40%-70%, and vs is greater than 70% (inclusive).

[0062] The data in the table above represent cryptopotassium manganese oxide at a 2θ angle of 12.763° and a d-interval of [missing information]. The relative intensity I / I0×100 is wm, and so on. Those skilled in the art are aware of the method of representing this table, and the present invention will not describe it in detail here.

[0063] The crypto-KMnO type oxide is a nanoparticle, and both of these methods, including Ti doping, increase the ratio of the diffraction peak intensities of the (211) crystal plane (2θ = 37.734 ± 0.30°) to the (310) crystal plane (2θ = 28.899 ± 0.30°) in the XRD pattern of the catalyst. In this invention, it is advantageous for the ratio of the diffraction peak intensities of the two crystal planes to be within an appropriate range. According to a preferred embodiment of the invention, the ratio of the diffraction peak intensities of the (211) crystal plane (2θ = 37.734 ± 0.30°) to the (310) crystal plane (2θ = 28.899 ± 0.30°) is 1-1.4.

[0064] In this invention, the phase analysis of the dehydrogenation catalyst was performed using an Advance D8 X-ray powder diffractometer (XRD) manufactured by Bruker GmbH, Germany. The test was conducted using Cu target Kα rays, Vantec-1 detector, at 40 kV and 40 mA, with a scanning range of 10° to 80° and a scanning step size of 5° / min.

[0065] A second aspect of the present invention provides a method for preparing the dehydrogenation catalyst of the present invention, the method comprising:

[0066] (1) Fe source, K source, Ce source, group VIB metal element source, group VIII metal element source, IIIB, IVB and / or group VB metal element source, alkaline earth metal source are mixed in the corresponding proportions and the precursor is obtained by first calcination.

[0067] (2) The precursor is mixed with crypto-potassium manganese oxide, molded and dried to obtain a dehydrogenation catalyst.

[0068] In this invention, the range of selectable conditions for the first roasting is relatively wide. According to a preferred embodiment of this invention, the first roasting conditions include: a temperature of 600-900℃; the roasting time can be reasonably adjusted according to actual needs, preferably, the roasting time is 3-7h.

[0069] In this invention, there is no particular limitation on the heating rate of the first calcination. According to a preferred embodiment of the invention, the heating rate is 10-15°C / min. In the embodiments of the invention, a heating rate of 12°C / min is used as an example to illustrate the advantages of the invention, but this does not limit the scope of the invention.

[0070] In this invention, the range of types of Fe source, K source, Ce source, Group VIB metal element source, Group VIII metal element source, IIIB, IVB and / or Group VB metal element source, and alkaline earth metal source that can be selected is relatively wide. According to a preferred embodiment of this invention, the Fe source, K source, Ce source, Group VIB metal element source, Group VIII metal element source, IIIB, IVB and / or Group VB metal element source, and alkaline earth metal source are each oxide of the element and / or salt of the element; taking the Fe source as an example, the Fe source is selected from one or more of Fe oxides and Fe soluble salts.

[0071] According to a preferred embodiment of the present invention, the Fe source is selected from one or more of ferric oxide, ferric chloride, ferric acetate, ferric nitrate, and ferric sulfate.

[0072] According to a preferred embodiment of the present invention, the K source is selected from one or more of potassium carbonate, potassium bicarbonate, potassium nitrate, potassium chloride, and potassium sulfate.

[0073] According to a preferred embodiment of the present invention, the Ce source is selected from one or more of cerium carbonate, cerium oxalate, cerium nitrate, cerium acetate, cerium chloride, and cerium sulfate.

[0074] According to a preferred embodiment of the present invention, the group VIB metal element is preferably Mo and / or W, wherein the Mo source is selected from one or more of ammonium molybdate and ammonium phosphomolybdate, and the W source is selected from one or more of ammonium tungstate, phosphotungstic acid, and ammonium metatungstate.

[0075] According to a preferred embodiment of the present invention, the group VIII metal element is preferably Co and / or Ni, wherein the Co source is selected from one or more of cobalt nitrate, cobalt acetate, cobalt chloride, cobalt sulfate, and cobalt acetylacetonate, and the Ni source is selected from one or more of nickel nitrate, nickel acetate, nickel chloride, nickel sulfate, and nickel acetylacetonate.

[0076] According to a preferred embodiment of the present invention, the group IIIB, IVB and / or VB metal elements are preferably selected from at least one of Sc, Y, V, Nb or Zr, more preferably Zr, wherein the Zr source is selected from one or more of zirconium carbonate, zirconium acetate, zirconium nitrate, zirconium oxalate or zirconium oxychloride.

[0077] According to a preferred embodiment of the present invention, the alkaline earth metal is preferably selected from at least one of Be, Mg, Ca, Sr and Ba, more preferably Mg and / or Ca, and most preferably Ca, wherein the Ca source is selected from one or more of calcium oxide, calcium carbonate, calcium acetate, calcium chloride, calcium sulfate and calcium hydroxide.

[0078] In step (2), the molding is for extruding to prepare integral structured catalyst particles (e.g., integral structured catalyst particles with a diameter of 2-5 mm and a length of 3-10 mm). There is no particular limitation on the molding method. According to a preferred embodiment of the present invention, the molding is kneading molding, preferably extrusion molding.

[0079] In step (2), moisture can be added or evaporated as needed during the molding process; for drying, in order to remove moisture, there are no particular limitations on the drying conditions. According to a preferred embodiment of the present invention, the drying temperature is 60-180℃, and the drying time can be determined according to actual needs; in the embodiments of the present invention, drying at 80℃ for 4 hours and drying at 120℃ for 10 hours are used as examples to illustrate the advantages of the present invention, but this does not limit the scope of the present invention.

[0080] This invention does not particularly limit the preparation method. According to a preferred embodiment of this invention, a method for preparing crypto-potassium manganese oxide is provided, comprising:

[0081] K₂CO₃, Mn₂O₃, and TiO₂ were mixed in a mass ratio of 1:(1.1-2):(3.8-5.1) and then subjected to a second calcination. In the second calcination, crypto-potassium manganese oxides with a microstructure of nanoparticles were prepared.

[0082] In this invention, the range of selectable conditions for the second roasting is relatively wide. According to a preferred embodiment of this invention, the second roasting conditions include: a temperature of 1000-1200℃; the roasting time can be reasonably adjusted according to actual needs, preferably 6-10h, and more preferably 7.5-9h.

[0083] In this invention, there is no particular limitation on the heating rate of the second calcination. According to a preferred embodiment of the invention, the heating rate is 6-12°C / min. In the embodiments of the invention, a heating rate of 8°C / min is used as an example to illustrate the advantages of the invention, but this does not limit the scope of the invention.

[0084] According to a preferred embodiment of the present invention, the mass ratio of K2CO3 to Mn2O3 is 1:(1.12-1.93).

[0085] According to a preferred embodiment of the present invention, the mass ratio of K2CO3 to TiO2 is 1:(3.94-5.06).

[0086] In this invention, there are no particular limitations on the atmosphere of the first and second roasting processes, as long as it is an oxygen-containing atmosphere. According to a preferred embodiment of this invention, the atmosphere is air.

[0087] A third aspect of the present invention provides the application of the dehydrogenation catalyst described herein in the dehydrogenation of alkylbenzene to prepare alkenylbenzene.

[0088] The dehydrogenation catalyst of this invention is used in the dehydrogenation of alkylbenzene (e.g., ethylbenzene) to alkenylbenzene (e.g., styrene). It has the characteristics of high catalytic activity, good stability and simple preparation process, and is suitable for large-scale industrial production.

[0089] A fourth aspect of the present invention provides a method for the dehydrogenation of ethylbenzene to styrene, the method comprising:

[0090] In the presence of a catalyst, ethylbenzene and water are contacted to carry out a dehydrogenation reaction; the catalyst includes the dehydrogenation catalyst described in this invention.

[0091] In this invention, there are no special requirements for the ratio of ethylbenzene to water. Conventional ratios in the art can achieve the purpose of this invention. According to a preferred embodiment of this invention, the water ratio is 0.8-2.0 by weight.

[0092] According to a preferred embodiment of the present invention, the space velocity of ethylbenzene is 0.2-2.0 h⁻¹. -1 .

[0093] According to a preferred embodiment of the present invention, the dehydrogenation reaction conditions include: a temperature of 560-650°C and an absolute pressure of 20-100 kPa.

[0094] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0095] To illustrate the invention more clearly, the following embodiments are provided, but the scope of the invention is not limited to the embodiments.

[0096] In this invention, the dehydrogenation catalyst is evaluated for activity in an isothermal fixed bed. The process for evaluating the activity of the ethylbenzene dehydrogenation catalyst for styrene production is briefly described below:

[0097] 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.

[0098] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0099] In the following examples, the K content in the crypto-potassium manganese oxide was determined by ICP.

[0100] Example 1

[0101] 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 46.4 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, was obtained, with a K content of 6.55 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is shown in Figure 1, and the X-ray diffraction pattern is shown in the table below.

[0102] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0103] Measurements showed that the particle size of the crypto-potassium manganese oxide was 57 nm.

[0104] Figure 2 shows the SEM image of the crypto-potassium manganese oxide, which can be seen as uniform nanoparticles.

[0105] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0106] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0107] The XRD pattern of the catalyst is shown in Figure 3. Diffraction peaks exist at 2θ of 12.768°, 18.125°, 49.955°, and 60.268°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0108] The SEM-EDS electron microscope image of the catalyst is shown in Figure 4, and the STEM-EDS electron microscope image is shown in Figure 5. It can be seen that the K, Mn and Ti elements are uniformly distributed.

[0109] The XPS spectrum of the catalyst is shown in Figure 6. In the XPS spectrum, the proportion of trivalent iron in the Fe 2p spectrum peak is 58.2%.

[0110] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 72.8%, and the styrene selectivity was 95.7%. After 500 hours of reaction, the ethylbenzene conversion reached 72.7%, and the styrene selectivity was 95.6%.

[0111] Example 2

[0112] 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 49 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, was obtained, with a K content of 6.46 wt% and a Mn to Ti molar ratio of 1:3.17. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1. The X-ray diffraction pattern is shown in the table below.

[0113] Measurements showed that the particle size of the crypto-potassium manganese oxide was 58 nm.

[0114] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0115] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0116] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 56.1%.

[0117] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.752°, 18.122°, 50.037°, and 60.255°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0118] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹.-1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 71.5%, and the styrene selectivity was 94.6%. After 500 hours of reaction, the ethylbenzene conversion reached 71.3%, and the styrene selectivity was 94.5%.

[0119] Example 3

[0120] 10 parts K₂CO₃, 12.1 parts Mn₂O₃, and 49.6 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, was obtained, with a K content of 6.55 wt% and a Mn to Ti molar ratio of 1:4.05. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1. The X-ray diffraction patterns are shown in the table below.

[0121] Measurements showed that the particle size of the crypto-potassium manganese oxide was 60 nm.

[0122] Weigh out 56 parts of ferric oxide (Fe₂O₃), 9.2 parts of potassium carbonate (K₂O), 11 parts of cerium nitrate (CeO₂), 6.5 parts of ammonium molybdate (MoO₃), 4.4 parts of cobalt acetate (Co₃O₄), 3.2 parts of zirconium carbonate (ZrO₂), and 1.2 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0123] 8.5 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Then, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0124] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 57.3%.

[0125] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.758°, 18.129°, 49.986°, and 60.264°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0126] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 72.2%, and the styrene selectivity was 95.3%. After 500 hours of reaction, the ethylbenzene conversion reached 72.1%, and the styrene selectivity was 95.2%.

[0127] Example 4

[0128] Weigh 10 parts K₂CO₃, 19.3 parts Mn₂O₃, and 42.4 parts TiO₂, mix them thoroughly, grind them completely, place them in a muffle furnace, and calcine them at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, is obtained, with a K content of 6.45 wt% and a Mn to Ti molar ratio of 1:2.18. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1, and the X-ray diffraction pattern is shown in the table below:

[0129] Measurements showed that the particle size of the crypto-potassium manganese oxide was 55 nm.

[0130] Weigh out 72 parts of ferric oxide (Fe2O3), 10 parts of potassium carbonate (K2O), 6.4 parts of cerium nitrate (CeO2), 2.5 parts of ammonium molybdate (MoO3), 2.4 parts of cobalt acetate (Co3O4), 2 parts of zirconium carbonate (ZrO2), and 0.5 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0131] 4.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Then, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0132] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 57.1%.

[0133] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.764°, 18.121°, 50.006°, and 60.247°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0134] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 72.0%, and the styrene selectivity was 95.2%. After 500 hours of reaction, the ethylbenzene conversion reached 71.8%, and the styrene selectivity was 95.1%.

[0135] Example 5

[0136] 10 parts K₂CO₃, 18.6 parts Mn₂O₃, and 46.4 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, was obtained, with a K content of 6.42 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1. The X-ray diffraction pattern is shown in the table below.

[0137] Measurements showed that the particle size of the crypto-potassium manganese oxide was 56 nm.

[0138] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0139] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0140] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 55.8%.

[0141] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.779°, 18.143°, 50.052°, and 60.285°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0142] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 71.4%, and the styrene selectivity was 94.5%. After 500 hours of reaction, the ethylbenzene conversion reached 71.2%, and the styrene selectivity was 94.4%.

[0143] Example 6

[0144] Weigh 10 parts K₂CO₃, 11.2 parts Mn₂O₃, and 46.4 parts TiO₂, mix thoroughly, grind completely, place in a muffle furnace, heat to 1000℃ at 8℃ / min, calcine for 8 hours, and allow to cool naturally to obtain product one, a crypto-potassium manganese oxide with a K content of 6.63 wt% and a Mn to Ti molar ratio of 1:4.1. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1, and the X-ray diffraction pattern is shown in the table below:

[0145] Measurements showed that the particle size of the crypto-potassium manganese oxide was 59 nm.

[0146] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0147] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0148] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 54.9%.

[0149] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.745°, 18.104°, 50.127°, and 60.274°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0150] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 70.8%, and the styrene selectivity was 94.0%. After 500 hours of reaction, the ethylbenzene conversion reached 70.5%, and the styrene selectivity was 93.8%.

[0151] Example 7

[0152] 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 39.4 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, was obtained, with a K content of 6.67 wt% and a Mn to Ti molar ratio of 1:2.5. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1. The X-ray diffraction pattern is shown in the table below.

[0153] Measurements showed that the particle size of the crypto-potassium manganese oxide was 54 nm.

[0154] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0155] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0156] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p spectrum peaks is 55.0%.

[0157] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.748°, 18.117°, 50.092°, and 60.251°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0158] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 70.9%, and the styrene selectivity was 94.3%. After 500 hours of reaction, the ethylbenzene conversion reached 70.6%, and the styrene selectivity was 94.2%.

[0159] Example 8

[0160] 10 parts K₂CO₃, 20.0 parts Mn₂O₃, and 46.4 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, crypto-KMn oxide was obtained. The K content of the crypto-KMn oxide was 6.59 wt%, and the molar ratio of Mn to Ti was 1:2.3. The XRD pattern of the crypto-KMn oxide is similar to that in Figure 1. The X-ray diffraction patterns are shown in the table below.

[0161] Measurements showed that the particle size of the crypto-potassium manganese oxide was 55 nm.

[0162] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0163] The crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until they were uniformly mixed, and an appropriate amount of water was added. Then, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0164] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 48.5%.

[0165] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.751°, 18.114°, 50.125°, and 60.276°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0166] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 69.6%, and the styrene selectivity was 93.2%. After 500 hours of reaction, the ethylbenzene conversion reached 68.4%, and the styrene selectivity was 92.5%.

[0167] Example 9

[0168] Weigh 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 46.4 parts TiO₂, mix them thoroughly, grind them completely, place them in a muffle furnace, and calcine them at 1000℃ for 6.5 h at a rate of 7℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, is obtained, with a K content of 6.51 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1, and the X-ray diffraction pattern is shown in the table below:

[0169] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0170] Measurements showed that the particle size of the crypto-potassium manganese oxide was 35 nm.

[0171] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0172] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0173] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.753°, 18.114°, 49.938°, and 60.261°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0174] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 57.7%.

[0175] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 72.2%, and the styrene selectivity was 95.9%. After 500 hours of reaction, the ethylbenzene conversion reached 71.9%, and the styrene selectivity was 95.4%.

[0176] Example 10

[0177] Weigh 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 46.4 parts TiO₂, mix them thoroughly, grind them completely, place them in a muffle furnace, and calcine them at 1200℃ for 9.5 h at a rate of 11℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, is obtained, with a K content of 6.58 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1, and the X-ray diffraction pattern is shown in the table below:

[0178] Measurements showed that the particle size of the crypto-potassium manganese oxide was 87 nm.

[0179] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0180] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0181] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0182] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.706°, 18.075°, 49.984°, and 60.318°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0183] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 58.7%.

[0184] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 72.7%, and the styrene selectivity was 95.5%. After 500 hours of reaction, the ethylbenzene conversion reached 72.1%, and the styrene selectivity was 95.1%.

[0185] Example 11

[0186] Weigh 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 46.4 parts TiO₂, mix thoroughly, grind completely, place in a muffle furnace, heat to 1000℃ at 8℃ / min, calcine for 8 hours, and allow to cool naturally to obtain product one, a crypto-potassium manganese oxide with a K content of 6.55 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1, and the X-ray diffraction pattern is shown in the table below:

[0187] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0188] Measurements showed that the particle size of the crypto-potassium manganese oxide was 57 nm.

[0189] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0190] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0191] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.768°, 18.125°, 49.955°, and 60.268°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0192] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 58.2%.

[0193] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 0.85 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 69.6%, and the styrene selectivity was 96.4%. After 500 hours of reaction, the ethylbenzene conversion reached 68.5%, and the styrene selectivity was 95.7%.

[0194] Example 12

[0195] 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 46.4 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, was obtained, with a K content of 6.55 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is shown in Figure 1, and the X-ray diffraction pattern is shown in the table below.

[0196] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0197] Measurements showed that the particle size of the crypto-potassium manganese oxide was 56 nm.

[0198] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium tungstate (WO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0199] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0200] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.775°, 18.024°, 49.908°, and 60.148°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0201] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 57.8%.

[0202] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 72.2%, and the styrene selectivity was 95.5%. After 500 hours of reaction, the ethylbenzene conversion reached 71.9%, and the styrene selectivity was 95.2%.

[0203] Example 13

[0204] 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 46.4 parts TiO₂ were weighed, mixed thoroughly, and then ground completely. The mixture was placed in a muffle furnace and calcined at 1000℃ for 8 hours at a rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, was obtained, with a K content of 6.58 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is shown in Figure 1, and the X-ray diffraction pattern is shown in the table below.

[0205] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0206] Measurements showed that the particle size of the crypto-potassium manganese oxide was 59 nm.

[0207] Weigh out 66 parts of ferric oxide (Fe₂O₃), 8.8 parts of potassium carbonate (K₂O), 8.9 parts of cerium nitrate (CeO₂), 4.2 parts of ammonium molybdate (MoO₃), 3 parts of nickel nitrate (NiO), 2.3 parts of zirconium carbonate (ZrO₂), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0208] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0209] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.695°, 18.012°, 49.916°, and 60.133°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0210] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 57.7%.

[0211] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 72.1%, and the styrene selectivity was 95.3%. After 500 hours of reaction, the ethylbenzene conversion reached 71.7%, and the styrene selectivity was 95.1%.

[0212] Comparative Example 1

[0213] Weigh 0.87 parts K2CO3, 1.32 parts Mn2O3, and 4.01 parts TiO2. Weigh ferric oxide equivalent to 66 parts Fe2O3, potassium carbonate equivalent to 8.8 parts K2O, cerium nitrate equivalent to 8.9 parts CeO2, ammonium molybdate equivalent to 4.2 parts MoO3, cobalt acetate equivalent to 3 parts Co3O4, zirconium carbonate equivalent to 2.3 parts ZrO2, and calcium carbonate equivalent to 0.6 parts CaO. Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain a solid.

[0214] The obtained solid was stirred in a container for 2 hours until it was uniformly mixed, and an appropriate amount of water was added. Then, it was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 5 mm. These particles were then placed in an oven and dried at 80°C for 4 hours and then at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0215] The XRD pattern of the catalyst is shown in Figure 7. No diffraction peaks were found at 12.763±0.30°, 18.126±0.30°, 50.077±0.30°, and 60.268±0.30°. The XRD pattern of the catalyst shows characteristic diffraction peaks of potassium polyferrate crystals.

[0216] The XPS spectrum of the catalyst is shown in Figure 8. The proportion of trivalent iron in the Fe 2p spectrum peaks is 46.7%.

[0217] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹.-1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 68.2%, and the styrene selectivity was 92.3%. After 500 hours of reaction, the ethylbenzene conversion reached 67.3%, and the styrene selectivity was 91.6%.

[0218] Comparative Example 2

[0219] Weigh out 68 parts of ferric oxide (Fe2O3), 9.8 parts of potassium carbonate (K2O), 9.9 parts of cerium nitrate (CeO2), 5.2 parts of ammonium molybdate (MoO3), 4 parts of cobalt acetate (Co3O4), 2.5 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0220] Product 2 was stirred in a mixing container for 2 hours until homogeneous, and then an appropriate amount of water was added. Subsequently, it was extruded and pelletized 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst. The proportion of trivalent iron in the Fe 2p spectrum of the catalyst was 45.5%. The XRD pattern of the catalyst showed characteristic diffraction peaks indicating the presence of potassium polyferrate crystals.

[0221] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 66.9%, and the styrene selectivity was 91.2%. After 500 hours of reaction, the ethylbenzene conversion reached 66.1%, and the styrene selectivity was 90.5%.

[0222] Comparative Example 3

[0223] Weigh 10 parts K₂CO₃ and 61.2 parts Mn₂O₃, mix them thoroughly, grind them completely, place them in a muffle furnace, and calcine them at 1000℃ for 8 hours with a heating rate of 8℃ / min. After natural cooling, product one, crypto-potassium manganese oxide, is obtained. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1. The X-ray diffraction pattern is shown in the table below:

[0224] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0225] Measurements showed that the particle size of the crypto-potassium manganese oxide was 63 nm.

[0226] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0227] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0228] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.761°, 18.115°, 50.085°, and 60.174°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0229] In the XPS spectrum of the catalyst, the proportion of ferric iron in the Fe 2p peak is 47.1%.

[0230] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 68.9%, and the styrene selectivity was 92.5%. After 500 hours of reaction, the ethylbenzene conversion reached 67.5%, and the styrene selectivity was 91.4%.

[0231] Comparative Example 4

[0232] Weigh 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 77 parts TiO₂, mix them thoroughly, grind them completely, place them in a muffle furnace, and calcine them at 1000℃ for 8 hours with a heating rate of 8℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, is obtained, with a molar ratio of Mn to Ti of 1:5. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1, and the X-ray diffraction pattern is shown in the table below:

[0233] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0234] Measurements showed that the particle size of the crypto-potassium manganese oxide was 66 nm.

[0235] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0236] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0237] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.755°, 18.146°, 50.017°, and 60.109°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0238] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p spectrum peaks is 47.5%.

[0239] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 69.3%, and the styrene selectivity was 92.7%. After 500 hours of reaction, the ethylbenzene conversion reached 67.9%, and the styrene selectivity was 91.8%.

[0240] Comparative Example 5

[0241] Weigh 10 parts K₂CO₃, 15.3 parts Mn₂O₃, and 46.4 parts TiO₂, mix them thoroughly, grind them completely, place them in a muffle furnace, and calcine them at 1300℃ for 10.5 h at a rate of 14℃ / min. After natural cooling, product one, a crypto-potassium manganese oxide, is obtained, with a K content of 6.59 wt% and a Mn to Ti molar ratio of 1:3. The XRD pattern of the crypto-potassium manganese oxide is similar to that in Figure 1, and the X-ray diffraction pattern is shown in the table below:

[0242] This indicates that the crypto-potassium manganese oxide matches the crypto-potassium manganese crystal form, and the crypto-potassium manganese oxide was successfully obtained.

[0243] Measurements showed that the particle size of the crypto-potassium manganese oxide was 101 nm.

[0244] Weigh out 66 parts of ferric oxide (Fe2O3), 8.8 parts of potassium carbonate (K2O), 8.9 parts of cerium nitrate (CeO2), 4.2 parts of ammonium molybdate (MoO3), 3 parts of cobalt acetate (Co3O4), 2.3 parts of zirconium carbonate (ZrO2), and 0.6 parts of calcium carbonate (CaO). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours at a rate of 12℃ / min to obtain product two.

[0245] 6.2 parts of crypto-potassium manganese oxide and product 2 were stirred in a mixing container for 2 hours until uniformly mixed, and an appropriate amount of water was added. Subsequently, the mixture 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 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0246] The XRD pattern of the catalyst is similar to that in Figure 3. Diffraction peaks are present at 2θ of 12.717°, 18.139°, 49.885°, and 60.145°, which are characteristic diffraction peaks of crypto-potassium manganese oxide, indicating that the catalyst contains crypto-potassium manganese oxide. In addition, the catalyst also contains characteristic diffraction peaks of potassium polyferrate crystals.

[0247] In the XPS spectrum of the catalyst, the proportion of trivalent iron in the Fe 2p peak is 58.9%.

[0248] 100 mL of catalyst was loaded into the reactor and incubated at 70 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the conditions of a reaction temperature of 620℃ and a water ratio of 1.0 by weight. After 100 hours of reaction, the ethylbenzene conversion reached 67.6%, and the styrene selectivity was 92.8%. After 500 hours of reaction, the ethylbenzene conversion reached 66.1%, and the styrene selectivity was 91.9%.

[0249] The data from the examples and comparative examples are summarized in the table below:

[0250] The data in the examples show that when cryptomonas oxide is present, the catalyst achieves excellent ethylbenzene conversion and styrene selectivity after 100 h of reaction, and the ethylbenzene conversion and styrene selectivity remain at a high level after 500 h of reaction; when cryptomonas oxide is not present, the ethylbenzene conversion and styrene selectivity of the catalyst are less satisfactory (see Comparative Examples 1 and 2).

[0251] When the crypto-KMn oxide is a titanium-doped crypto-KMn oxide, and the molar ratio of Mn to Ti is in the range of 1:1.9-4.5, the catalyst exhibits excellent and stable ethylbenzene conversion and styrene selectivity. When the crypto-KMn oxide is not doped with titanium (see Comparative Example 3) or the titanium doping is excessive (see Comparative Example 4), the catalyst activity decreases. It should be noted that in Example 8, due to the large amount of Mn2O3, the mass ratio of K2CO3 to Mn2O3 is relatively low (10 parts by weight: 20 parts by weight = 1:2), so the catalyst activity is slightly inferior to that in other examples.

[0252] When the crypto-KMnO type oxide is in the form of nanoparticles with a particle size in the range of 30-90 nm, the catalyst achieves excellent and stable ethylbenzene conversion and styrene selectivity. In Comparative Example 5, due to the long calcination time, high calcination temperature, and large heating rate, the calcination conditions of this invention were exceeded, resulting in an excessively large particle size of the crypto-KMnO type oxide (101 nm), and the catalyst activity did not reach the expected level.

[0253] As mentioned above, both the crypto-KMnO type oxide nanoparticles and the use of Ti doping increase the ratio of the diffraction peak intensities of the (211) crystal plane (2θ = 37.734 ± 0.30°) to the (310) crystal plane (2θ = 28.899 ± 0.30°) in the XRD pattern of the catalyst. When the ratio of this peak intensity is in the range of 1-1.4, the catalyst achieves excellent and stable ethylbenzene conversion and styrene selectivity. Comparative Example 3 was prepared using the solid-phase molten salt method of the present invention, forming crypto-KMnO type oxide nanoparticles. However, since Ti was not used for doping, the peak intensity ratio was already at the edge of the range of 1-1.4, resulting in the catalyst activity not reaching the expected level.

[0254] Furthermore, it is worth noting that the catalyst of the present invention exhibits a slight decrease in ethylbenzene conversion and styrene selectivity under low water ratio conditions of 0.85 by weight (see Example 11), but still slightly higher than the corresponding levels of the catalyst in the comparative example. This indicates that the catalyst of the present invention can be used with acceptable activity under low water ratio conditions.

[0255] When MoO3 is replaced with WO3, which is also a group VIB metal oxide (see Example 12), or when Co3O4 is replaced with NiO, which is also a group VIII metal oxide (see Example 13), the catalyst of the present invention still achieves excellent and stable catalytic activity.

[0256] The preferred 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 combinations of 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. A dehydrogenation catalyst, characterized in that, The catalyst comprises the following components based on the total weight of the catalyst: Cryptomonoxide-type oxides, with a content of 4.2 wt%-8.5 wt%; Fe2O3 content is 56.0wt%-72.0wt%; K2O, with a content of 5.6wt%-10.0wt%; CeO2 content is 6.0wt%-11.0wt%; The content of the group VIB metal element oxide is 2.0wt%-6.5wt%, and the group VIB metal element oxide is preferably MoO3 and / or WO3, more preferably MoO3; The oxides of Group VIII metal elements are present in a content of 2.0 wt% to 4.4 wt%, and the oxides of Group VIII metal elements are preferably Co3O4 and / or NiO, more preferably Co3O4; The oxides of group IIIB, IVB and / or VB metal elements are present in a content of 1.8wt%-3.2wt%, wherein the oxides of group IIIB, IVB and / or VB metal elements are preferably selected from at least one of Sc2O3, Y2O3, V2O5, Nb2O5 or ZrO2, and more preferably ZrO2; The alkaline earth metal oxide has a content of 0.3wt%-1.2wt%, and the alkaline earth metal oxide is preferably selected from at least one of BeO, MgO, CaO, SrO and BaO, more preferably MgO and / or CaO, and most preferably CaO.

2. The dehydrogenation catalyst according to claim 1, wherein, In the XRD pattern of the dehydrogenation catalyst, at least one diffraction peak exists at 2θ of 12.763±0.30°, 18.126±0.30°, 50.077±0.30°, and 60.268±0.30°.

3. The dehydrogenation catalyst according to claim 1 or 2, wherein, The content of cryptopotassium manganese oxide is 5.4 wt%–7.6 wt%; and / or In the XPS spectrum of the dehydrogenation catalyst, the proportion of trivalent iron in the Fe 2p peak is greater than 48%, preferably greater than 54%.

4. The dehydrogenation catalyst according to any one of claims 1-3, wherein, The crypto-potassium manganese oxide contains 6.4 wt% to 6.8 wt% K; and / or The crypto-potassium manganese oxide is a titanium-doped crypto-potassium manganese oxide, preferably with a molar ratio of Mn to Ti of 1:1.9-4.5; and / or The dehydrogenation catalyst contains potassium polyferrate crystals.

5. The dehydrogenation catalyst according to any one of claims 1-4, wherein, The crypto-potassium manganese oxide includes the X-ray diffraction pattern shown below. a: ±0.30°, b: varies with 2θ Preferably, the ratio of the diffraction peak intensity of the (211) crystal plane (2θ=37.734±0.30°) to that of the (310) crystal plane (2θ=28.899±0.30°) is 1-1.

4.

6. The dehydrogenation catalyst according to any one of claims 1-5, wherein, The crypto-potassium manganese oxide is in the form of nanoparticles with a particle size of 30-90 nm, preferably 40-80 nm.

7. A method for preparing the dehydrogenation catalyst according to any one of claims 1-6, characterized in that, The method includes: (1) Fe source, K source, Ce source, group VIB metal element source, group VIII metal element source, IIIB, IVB and / or group VB metal element source, alkaline earth metal source are mixed in the corresponding proportions and the precursor is obtained by first calcination. (2) The precursor is mixed with crypto-potassium manganese oxide, molded and dried to obtain a dehydrogenation catalyst.

8. The preparation method according to claim 7, wherein, The first roasting conditions include: a temperature of 600-900℃ and a roasting time of 3-7 hours; and / or The Fe source, K source, Ce source, group VIB metal element source, group VIII metal element source, group IIIB, IVB and / or group VB metal element source, and alkaline earth metal source are each oxide of the element and / or salt of the element. Preferably, the Fe source is selected from one or more of ferric oxide, ferric chloride, ferric acetate, ferric nitrate, and ferric sulfate; and / or The K source is selected from one or more of potassium carbonate, potassium bicarbonate, potassium nitrate, potassium chloride, and potassium sulfate; and / or The Ce source is selected from one or more of cerium carbonate, cerium oxalate, cerium nitrate, cerium acetate, cerium chloride, and cerium sulfate; and / or The group VIB metal element is preferably Mo and / or W, wherein the Mo source is selected from one or more of ammonium molybdate and ammonium phosphomolybdate, and the W source is selected from one or more of ammonium tungstate, phosphotungstic acid, or ammonium metatungstate; and / or The Group VIII metal element is preferably Co and / or Ni, wherein the Co source is selected from one or more of cobalt nitrate, cobalt acetate, cobalt chloride, cobalt sulfate, and cobalt acetylacetonate, and the Ni source is selected from one or more of nickel nitrate, nickel acetate, nickel chloride, nickel sulfate, and nickel acetylacetonate; and / or The group IIIB, IVB and / or VB metal elements are preferably selected from at least one of Sc, Y, V, Nb or Zr, more preferably Zr, wherein the Zr source is selected from one or more of zirconium carbonate, zirconium acetate, zirconium nitrate, zirconium oxalate or zirconium oxychloride; and / or The alkaline earth metal is preferably selected from at least one of Be, Mg, Ca, Sr and Ba, more preferably Mg and / or Ca, and most preferably Ca, wherein the Ca source is selected from one or more of calcium oxide, calcium carbonate, calcium acetate, calcium chloride, calcium sulfate and calcium hydroxide.

9. The preparation method according to claim 7 or 8, wherein, The preparation method of the crypto-potassium manganese oxide includes: K2CO3, Mn2O3, and TiO2 are mixed in a mass ratio of 1:(1.1-2.0):(3.8-5.1) and then subjected to a second calcination. Preferably, the second calcination conditions include: a temperature of 1000-1200℃; and a calcination time of 6-10 hours, preferably 7.5-9 hours. Preferably, the mass ratio of K2CO3 to Mn2O3 is 1:(1.12-1.93); and / or The mass ratio of K2CO3 to TiO2 is 1:(3.94-5.06).

10. Use of crypto-potassium manganese oxides in the preparation of dehydrogenation catalysts.

11. The use of the dehydrogenation catalyst according to any one of claims 1-6 in the dehydrogenation of alkylbenzene to prepare alkenylbenzene.

12. A method for the dehydrogenation of ethylbenzene to styrene, characterized in that, The method includes: In the presence of a catalyst, ethylbenzene and water are brought into contact to undergo a dehydrogenation reaction; The catalyst comprises the dehydrogenation catalyst according to any one of claims 1-6; Preferably, The water ratio is 0.8-2.0 by weight; and / or The space velocity of ethylbenzene is 0.2-2.0 h⁻¹. -1 ; and / or The dehydrogenation reaction conditions include a temperature of 560-650℃ and an absolute pressure of 20-100kPa.

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