Dehydrogenation catalyst, method for preparing and using the same, and method for dehydrogenating alkylbenzene

Abstract

The present application relates to the technical field of dehydrogenation catalyst, and particularly relates to a dehydrogenation catalyst, a preparation method and application thereof, and a method for dehydrogenation of alkylbenzene; the dehydrogenation catalyst comprises Fe2O3, K2O, CeO2, Co3O4, VIB group metal element oxide, MnO2 and IVB group metal element oxide, and is based on the total weight of the catalyst; the oxygen desorption amount of the dehydrogenation catalyst in O2-TPD test is greater than 8.2 mmol / g. The catalyst surface has abundant oxygen vacancies (the oxygen desorption amount in O2-TPD test is greater than 8.2 mmol / g), and the migration ability of the active species on the catalyst surface is obviously enhanced. The dehydrogenation catalyst is applied to the reaction of dehydrogenation of alkylaromatic hydrocarbon (such as ethylbenzene) to prepare alkenyl aromatic hydrocarbon (such as styrene), and has the characteristics of high catalytic activity and good stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dehydrogenation catalyst, in particular to a dehydrogenation catalyst, a preparation method and application thereof, and a method for dehydrogenation of oxidized alkylbenzene. BACKGROUND

[0002] Styrene is an important basic organic raw material, mainly used for manufacturing polystyrene resin, unsaturated polyester resin, ion exchange resin, synthetic resin paint and insulator materials. These materials have very important uses in the automobile manufacturing, home appliance, textile, building material, light industry, toy and other industrial sectors. So far, the catalytic dehydrogenation of ethylbenzene has been the main technical route for the production of styrene at home and abroad, and its production capacity accounts for about 85% of the total styrene production capacity. In order to improve the production efficiency of ethylbenzene dehydrogenation, a large amount of high-temperature steam is usually introduced in industry. Water vapor plays a variety of important roles in the reaction, such as providing heat required for the reaction, promoting the chemical equilibrium to move towards styrene, eliminating catalyst surface carbon through water gas shift reaction, and oxidizing catalyst surface to maintain catalyst activity, etc.

[0003] Generally speaking, the dehydrogenation of hydrocarbons can be divided into two types of reactions: oxidative dehydrogenation and direct dehydrogenation. For the reaction of ethylbenzene dehydrogenation to styrene, the non-oxidative direct dehydrogenation catalyst has been widely used in large-scale industrial application, but it has the disadvantages of thermodynamic equilibrium limitation, large water vapor consumption, high energy consumption, and easy deactivation of catalyst. Iron or vanadium oxide is often used as catalyst in the process of oxidative dehydrogenation, and ethylbenzene is oxidatively dehydrogenated in air, oxygen or CO2 atmosphere, which can break the limitation of thermodynamic equilibrium. The most important core technology in this method is the research and development of high-performance oxidative ethylbenzene dehydrogenation catalyst for styrene. CN112844362B discloses a method for improving the activity of metal oxide catalyst in oxidation and oxidative dehydrogenation reaction. The metal oxide catalyst is treated in an acidic or basic solution, and the catalyst is restructured, the uniformity and activity of the active component are obviously improved, and the catalytic reaction performance is significantly improved. CN106000409B discloses an iron-based composite oxide catalyst for oxidative dehydrogenation of ethylbenzene to styrene. The active component of the catalyst is FeO x , the additive is any one of TiO2, PdO, ZnO and V2O5, and the carrier is γ-Al2O3. The catalyst is prepared by atomic layer deposition method, and has high dispersion of active component and good oxidative dehydrogenation performance of ethylbenzene.

[0004] However, in the catalytic reaction technology of oxidative ethylbenzene dehydrogenation to styrene, the catalyst preparation method so far does not have obvious benefits, and the catalytic activity and stability of the catalyst cannot fully meet the needs of the actual application of ethylbenzene dehydrogenation to styrene catalyst. SUMMARY

[0005] In order to solve the problems of low activity and poor stability of the ethylbenzene dehydrogenation catalyst in the prior art, and the problems of large water vapor consumption, large energy consumption and easy deactivation of the catalyst in the dehydrogenation process, the present application provides a dehydrogenation catalyst, a preparation method and application thereof, and a method for dehydrogenating oxidized alkylbenzene. The dehydrogenation catalyst is applied to the dehydrogenation of oxidized alkylaromatic hydrocarbon (such as ethylbenzene) to prepare alkenyl aromatic hydrocarbon (such as styrene), and has the characteristics of high catalytic activity and good stability.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a dehydrogenation catalyst, which comprises Fe2O3, K2O, CeO2, Co3O4, VIB group metal element oxide, MnO2 and IVB group metal element oxide, based on the total weight of the catalyst.

[0007] The second aspect of the present application provides a preparation method of the dehydrogenation catalyst described in the present application, which comprises:

[0008] (1) mixing Fe source, K source, Mn source and IVB group metal source, first drying, and first calcining;

[0009] (2) mixing Ce source, Co source and VIB group metal source, second drying, and second calcining to obtain a calcined product, mixing the calcined product with a solution containing polyol and alkali, and performing a solvothermal reduction reaction, followed by alcohol washing, vacuum drying or drying in an inert gas atmosphere;

[0010] (3) mixing the products obtained in steps (1) and (2), and shaping;

[0011] The mass ratio of the calcined product, polyol and alkali is 1:(35.8-44.2):(1.06-1.75).

[0012] The third aspect of the present application provides an application of the dehydrogenation catalyst described in the present application in the dehydrogenation of oxidized alkylaromatic hydrocarbon to prepare alkenyl aromatic hydrocarbon.

[0013] The fourth aspect of the present application provides a method for dehydrogenating oxidized alkylbenzene, which comprises:

[0014] In the presence of a catalyst and oxygen, contacting alkylbenzene and water to perform a dehydrogenation reaction to prepare alkenylbenzene;

[0015] The catalyst comprises the dehydrogenation catalyst described in the present application.

[0016] Through the above technical solution, compared with the prior art, the present application has the following advantages:

[0017] (1) The catalyst surface of the present invention has abundant oxygen vacancies (the oxygen desorption amount in the O2-TPD test is greater than 8.2 mmol / g), and the migration ability of active species on the catalyst surface will be significantly enhanced.

[0018] (2) This invention introduces abundant oxygen vacancies into the catalyst by controlling the preparation method and using a segmented synthesis method of different active components combined with a solvothermal reduction reaction.

[0019] (3) The dehydrogenation catalyst of this invention can be used to dehydrogenate alkyl aromatics (e.g., ethylbenzene) to prepare alkenyl aromatics (e.g., styrene). Introducing oxygen into the direct dehydrogenation process of alkyl aromatics (e.g., ethylbenzene) can break the thermodynamic equilibrium limitation of the reaction, causing the chemical equilibrium to shift towards the dehydrogenation to alkenyl aromatics (e.g., styrene), significantly improving the conversion rate of alkyl aromatics (e.g., ethylbenzene) in the reaction. The catalyst surface has abundant oxygen vacancies, which significantly enhances the migration ability of active species on the catalyst surface, significantly reducing carbon deposition and thus improving the stability of the catalyst. Attached Figure Description

[0020] Figure 1 The results are O2-TPD characterization tests of the catalysts obtained in Example 1 and Comparative Example 1 of this invention. Detailed Implementation

[0021] 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.

[0022] In this invention, the O2-TPD test was performed using an AutoChem II 2920 temperature-programmed chemisorption analyzer from Micromeritics. For each experiment, approximately 100 mg of sample was packed into a quartz tube, and the sample was heated at a rate of 10 °C / min under a high-purity He atmosphere, followed by pretreatment at 300 °C for 30 min. After pretreatment, the sample was allowed to cool to room temperature, and then 5% O2 / He was introduced for adsorption for 1 h. After adsorption was complete, He gas was introduced for purging for 30 min to remove physically weakly adsorbed O2. Once the baseline leveled out, the temperature was increased at a rate of 10 °C / min, and the desorption curve was recorded.

[0023] The first aspect of this invention provides a dehydrogenation catalyst, comprising, based on the total weight of the catalyst, Fe₂O₃, K₂O, CeO₂, Co₃O₄, oxides of Group VIB metals, MnO₂, and oxides of Group IVB metals; the dehydrogenation catalyst exhibits an oxygen desorption capacity greater than 8.2 mmol / g in an O₂-TPD test. The catalyst surface of this invention has abundant oxygen vacancies (oxygen desorption capacity greater than 8.2 mmol / g in the O₂-TPD test), significantly enhancing the migration ability of active species on the catalyst surface.

[0024] According to a preferred embodiment of the present invention, the Fe2O3 content is 56wt%-74wt%.

[0025] According to a preferred embodiment of the present invention, the K2O content is 5wt%-11wt%.

[0026] According to a preferred embodiment of the present invention, the CeO2 content is 8wt%-13wt%.

[0027] According to a preferred embodiment of the present invention, the content of group VIB metal oxides is 4wt%-8.5wt%.

[0028] According to a preferred embodiment of the present invention, the Co3O4 content is 3wt%-7.5wt%.

[0029] According to a preferred embodiment of the present invention, the MnO2 content is 2.1wt%-5.7wt%.

[0030] According to a preferred embodiment of the present invention, the content of group IVB metal oxides is 0.3wt%-1.5wt%.

[0031] According to a preferred embodiment of the present invention, the group VIB metal oxide is WO3 and / or MoO3, preferably WO3;

[0032] According to a preferred embodiment of the present invention, the oxide of the group IVB metal element is TiO2 and / or ZrO2, preferably TiO3.

[0033] A second aspect of the present invention provides a method for preparing the dehydrogenation catalyst of the present invention, the method comprising:

[0034] (1) After mixing Fe source, K source, Mn source and IVB group metal source, the mixture is first dried and then first calcined;

[0035] (2) After mixing Ce source, Co source and VIB group metal source, the mixture is dried and calcined to obtain calcined product. The calcined product is mixed with a solution containing polyol and alkali and subjected to solvothermal reduction reaction. Then it is washed with alcohol and dried under vacuum or in an inert gas atmosphere.

[0036] (3) Mix the products obtained in steps (1) and (2) and shape them;

[0037] The mass ratio of the calcined product, polyol, and alkali is 1:(35.8-44.2):(1.06-1.75).

[0038] This invention, through the regulation of the preparation method, adopts a segmented synthesis method of different active components combined with a solvothermal reduction reaction to introduce abundant oxygen vacancies into the catalyst, thereby effectively increasing the content of active oxygen species, accelerating the catalytic reaction on the catalyst surface, and enhancing the catalyst activity in the dehydrogenation of ethylbenzene to styrene reaction.

[0039] In this invention, steps (1) and (2) are only used to distinguish the preparation of intermediates of different components, and the order of steps (1) and (2) is not required.

[0040] According to a preferred embodiment of the present invention, in step (2), the mass ratio of the calcined product, polyol and alkali is 1:(37.2-42.6):(1.18-1.65).

[0041] According to a preferred embodiment of the present invention, the solvothermal reduction reaction conditions include: a temperature of 140-180℃; the reaction time can be reasonably adjusted according to actual needs, preferably 10-15h.

[0042] According to a preferred embodiment of the present invention, the heating rate is 10-15℃ / min.

[0043] In this invention, the range of polyols that can be selected in step (2) is relatively wide. According to a preferred embodiment of this invention, the polyol is selected from C2-C5 polyols, preferably at least one of diethylene glycol, triethylene glycol, ethylene glycol and propylene glycol, with diethylene glycol being the most preferred.

[0044] According to a preferred embodiment of the present invention, the alkali is selected from at least one of alkali metal hydroxides and ammonia water, such as at least one of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and ammonia water, preferably sodium hydroxide.

[0045] In this invention, the range of types of Fe source, K source, Ce source, Group VIB metal source, Mn source, Co source, and Group IVB metal source that can be selected is relatively wide. According to a preferred embodiment of this invention, each of the Fe source, K source, Ce source, Group VIB metal source, Mn source, Co source, and Group IVB metal source is an oxide of the element and / or a salt of the element. Taking the Fe source as an example, the Fe source is selected from one or more of the oxides of Fe and soluble salts of Fe.

[0046] According to a preferred embodiment of the present invention, the Fe source includes one or more of ferric oxide, ferric chloride, ferric acetate, ferric nitrate, and ferric sulfate.

[0047] According to a preferred embodiment of the present invention, the K source includes one or more of potassium carbonate, potassium bicarbonate, potassium nitrate, potassium chloride, and potassium sulfate.

[0048] According to a preferred embodiment of the present invention, the Ce source includes one or more of cerium carbonate, cerium oxalate, cerium nitrate, cerium acetate, cerium chloride, and cerium sulfate.

[0049] According to a preferred embodiment of the present invention, the group IVB metal source is one or more of ammonium molybdate, ammonium metamolybdate, phosphomolybdic acid, ammonium tungstate, ammonium metatungstate, and phosphotungstic acid.

[0050] According to a preferred embodiment of the present invention, the Co source includes one or more of cobalt nitrate, cobalt acetate, cobalt chloride, cobalt sulfate, and cobalt acetylacetonate.

[0051] According to a preferred embodiment of the present invention, the Mn source includes one or more of manganese dioxide, manganese chloride, manganese acetate, manganese nitrate, and manganese sulfate.

[0052] According to a preferred embodiment of the present invention, the group IVB metal source includes one or more of titanium dioxide, titanium tetrachloride, titanium sulfate, zirconium dioxide, zirconium tetrachloride, and zirconium sulfate.

[0053] In this invention, there are no particular limitations on the conditions for the first drying and the second drying, as long as the moisture can be removed. According to a preferred embodiment of this invention, the conditions for the first drying and the second drying include: oven drying, drying temperature of 60-80℃, and drying time of 20-40min.

[0054] In this invention, there are no particular limitations on the vacuum drying conditions, as long as the moisture can be removed. Preferably, the drying conditions include: vacuum oven drying, drying temperature of 75-85℃, and drying time of 9-12h.

[0055] In step (3), there are no special limitations on the molding process, as long as the products obtained in steps (1) and (2) are mixed evenly.

[0056] For example, the products obtained in steps (1) and (2) can be stirred in a mixing container until they are evenly mixed and an appropriate amount of water is added. Then, they are extruded, granulated, shaped, and dried to obtain a monolithic, well-structured finished catalyst.

[0057] In this invention, there is no particular limitation on the shape of the finished catalyst, which can be adjusted according to actual needs.

[0058] A third aspect of the present invention provides the application of the dehydrogenation catalyst described herein in the dehydrogenation of alkyl aromatics to prepare alkenyl aromatics.

[0059] The dehydrogenation catalyst described in this invention can be used to dehydrogenate alkyl aromatics (e.g., ethylbenzene) to alkenyl aromatics (e.g., styrene). Introducing oxygen into the direct dehydrogenation process of alkyl aromatics (e.g., ethylbenzene) breaks the thermodynamic equilibrium constraint of the reaction, shifting the chemical equilibrium towards dehydrogenation to alkenyl aromatics (e.g., styrene), significantly improving the conversion rate of alkyl aromatics (e.g., ethylbenzene) in the reaction. The catalyst surface has abundant oxygen vacancies, which significantly enhances the migration ability of active species on the catalyst surface, greatly reducing carbon deposition and thus improving catalyst stability.

[0060] A fourth aspect of the present invention provides a method for dehydrogenating alkylbenzenes, the method comprising:

[0061] Alkenylbenzene is prepared by contacting alkylbenzene with water in the presence of a catalyst and oxygen to carry out a dehydrogenation reaction.

[0062] The catalyst includes the dehydrogenation catalyst described in this invention.

[0063] According to a preferred embodiment of the present invention, the molar ratio of alkylbenzene to oxygen is 4-6.5:1.

[0064] According to a preferred embodiment of the present invention, the water ratio is 0.5-1.0 (wt).

[0065] According to a preferred embodiment of the present invention, the space velocity of alkylbenzene is 0.2-2.0 h⁻¹. -1 .

[0066] According to a preferred embodiment of the present invention, the dehydrogenation reaction conditions include: a temperature of 550-650°C and an absolute pressure of 20-100 kPa.

[0067] According to a preferred embodiment of the present invention, the alkylbenzene is ethylbenzene.

[0068] 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.

[0069] To illustrate the invention more clearly, the following embodiments are provided, but the scope of the invention is not limited to the embodiments.

[0070] In the following examples, the catalyst activity was evaluated in an isothermal fixed bed. Ethylbenzene-containing feedstock was contacted with the dehydrogenation catalyst in the presence of steam and O2 to undergo a dehydrogenation reaction. The process for evaluating the activity of the ethylbenzene dehydrogenation to styrene catalyst is briefly described below:

[0071] Deionized water, ethylbenzene, and O2 are separately fed into a preheating mixer via metering pumps or flow meters. After preheating and mixing into a gaseous state, the mixture enters the reactor, which is heated by an electric heating wire to reach a set temperature. The molar ratio of ethylbenzene to O2 is 5:1, and the water-to-oil ratio for the dehydrogenation reaction is 0.8. The reactor is a stainless steel tube, internally packed with 100 mL of catalyst. The reactants flowing out of the reactor are condensed in water and their composition is analyzed by gas chromatography.

[0072] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0073]

[0074]

[0075] Example 1

[0076] (1) Weigh 65 parts of Fe2O3, 8.5 parts of K2O, 3.1 parts of MnO2, and 0.7 parts of TiO2. Stir in a mixing container until the mixture is uniform. After drying, place in a muffle furnace and calcine at 800°C for 5 hours to obtain product one.

[0077] (2) Weigh 11.2 parts of cerium nitrate (CeO2), 6 parts of cobalt acetate (Co3O4), and 5.5 parts of ammonium tungstate (WO3), and stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800°C for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 120.74g of diethylene glycol and 4.32g of sodium hydroxide. React at 140°C for 12 hours. After washing several times with anhydrous ethanol, place in a vacuum oven and dry overnight at 80°C to obtain product two.

[0078] (3) Stir product one and product two in a mixing container for 2 hours until they are evenly mixed and add an appropriate amount of water. Then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 5 mm. Place them in an oven and dry at 80°C for 4 hours and at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0079] The catalyst exhibited an oxygen desorption capacity of 11.8 mmol / g in the O2-TPD test.

[0080] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 82.5%, and the styrene selectivity was 94.2%.

[0081] Example 2

[0082] Weigh out 65 parts of ferric oxide (Fe2O3), 8.5 parts of potassium carbonate (K2O), 3.1 parts of manganese nitrate (MnO2), and 0.7 parts of titanium dioxide (TiO2), stir them in a mixing container until they are evenly mixed, dry them, and then place them in a muffle furnace and calcine them at 800°C for 5 hours to obtain product one.

[0083] Weigh out cerium nitrate equivalent to 11.2 parts CeO2, cobalt acetate equivalent to 6 parts Co3O4, and ammonium tungstate equivalent to 5.5 parts WO3. Stir in a mixing container until homogeneous, dry, and then calcine in a muffle furnace at 800℃ for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 111.9g diethylene glycol and 4.32g sodium hydroxide. React at 140℃ for 12 hours. After washing several times with anhydrous ethanol, dry in a vacuum oven at 80℃ overnight to obtain product two.

[0084] Product 1 and Product 2 were stirred in a mixing container for 2 hours until they were evenly mixed, and an appropriate amount of water was added. Then, they were 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.

[0085] The catalyst exhibited an oxygen desorption capacity of 10.4 mmol / g in the O2-TPD test.

[0086] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 81.6%, and the styrene selectivity was 93.7%.

[0087] Example 3

[0088] (1) Weigh 74 parts of Fe2O3, 6 parts of K2O, 2.5 parts of MnO2, and 0.3 parts of TiO2. Stir them in a mixing container until they are evenly mixed. After drying, place them in a muffle furnace and calcine at 800°C for 5 hours to obtain product one.

[0089] (2) Weigh cerium nitrate equivalent to 9 parts CeO2, cobalt acetate equivalent to 4.2 parts Co3O4, and ammonium tungstate equivalent to 4 parts WO3. Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 111.6g propylene glycol and 4.95g sodium hydroxide. React at 160℃ for 15 hours. After washing several times with anhydrous ethanol, place in a vacuum oven and dry overnight at 80℃ to obtain product two.

[0090] (3) Stir product one and product two in a mixing container for 2 hours until they are evenly mixed and add an appropriate amount of water. Then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 5 mm. Place them in an oven and dry at 80°C for 4 hours and at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0091] The catalyst exhibited an oxygen desorption capacity of 9.6 mmol / g in the O2-TPD test.

[0092] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 80.7%, and the styrene selectivity was 93.3%.

[0093] Example 4

[0094] (1) Weigh 56 parts of Fe2O3, 10.5 parts of K2O, 5 parts of MnO2, and 1.5 parts of TiO2. Stir in a mixing container until the mixture is uniform. After drying, place in a muffle furnace and calcine at 800°C for 5 hours to obtain product one.

[0095] (2) Weigh cerium nitrate equivalent to 12 parts CeO2, cobalt acetate equivalent to 8 parts Co3O4, and ammonium tungstate equivalent to 7 parts WO3. Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 127.8g triethylene glycol and 3.54g sodium hydroxide. React at 180℃ for 10 hours. After washing several times with anhydrous ethanol, place in a vacuum oven and dry overnight at 80℃ to obtain product two.

[0096] (3) Stir product one and product two in a mixing container for 2 hours until they are evenly mixed and add an appropriate amount of water. Then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 5 mm. Place them in an oven and dry at 80°C for 4 hours and at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0097] The catalyst exhibited an oxygen desorption capacity of 9.7 mmol / g in the O2-TPD test.

[0098] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 The performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 80.9%, and the styrene selectivity was 93.4%.

[0099] Example 5

[0100] (1) Weigh 65 parts of Fe2O3, 8.5 parts of K2O, 3.1 parts of MnO2, and 0.7 parts of TiO2. Stir in a mixing container until the mixture is uniform. After drying, place in a muffle furnace and calcine at 800°C for 5 hours to obtain product one.

[0101] (2) Weigh 11.2 parts of cerium nitrate (CeO2), 6 parts of cobalt acetate (Co3O4), and 5.5 parts of ammonium tungstate (WO3), and stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800°C for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 120.74g of diethylene glycol and 3.54g of sodium hydroxide. React at 140°C for 12 hours. After washing several times with anhydrous ethanol, place in a vacuum oven and dry overnight at 80°C to obtain product two.

[0102] (3) Stir product one and product two in a mixing container for 2 hours until they are evenly mixed and add an appropriate amount of water. Then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 5 mm. Place them in an oven and dry at 80°C for 4 hours and at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0103] The catalyst exhibited an oxygen desorption capacity of 10.9 mmol / g in the O2-TPD test.

[0104] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 82.0%, and the styrene selectivity was 93.9%.

[0105] Example 6

[0106] (1) Weigh 65 parts of Fe2O3, 8.5 parts of K2O, 3.1 parts of MnO2, and 0.7 parts of TiO2. Stir in a mixing container until the mixture is uniform. After drying, place in a muffle furnace and calcine at 800°C for 5 hours to obtain product one.

[0107] (2) Weigh 11.2 parts of cerium nitrate (CeO2), 6 parts of cobalt acetate (Co3O4), and 5.5 parts of ammonium tungstate (WO3), and stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800°C for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 120.74g of diethylene glycol and 3.18g of sodium hydroxide. React at 140°C for 12 hours. After washing several times with anhydrous ethanol, place in a vacuum oven and dry overnight at 80°C to obtain product two.

[0108] (3) Stir product one and product two in a mixing container for 2 hours until they are evenly mixed and add an appropriate amount of water. Then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 5 mm. Place them in an oven and dry at 80°C for 4 hours and at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0109] The catalyst exhibited an oxygen desorption capacity of 8.8 mmol / g in the O2-TPD test.

[0110] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 80.1%, and the styrene selectivity was 92.8%.

[0111] Example 7

[0112] (1) Weigh 65 parts of Fe2O3, 8.5 parts of K2O, 3.1 parts of MnO2, and 0.7 parts of TiO2. Stir in a mixing container until the mixture is uniform. After drying, place in a muffle furnace and calcine at 800°C for 5 hours to obtain product one.

[0113] (2) Weigh 11.2 parts of cerium nitrate (CeO2), 6 parts of cobalt acetate (Co3O4), and 5.5 parts of ammonium tungstate (WO3), and stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800°C for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 107.4g of diethylene glycol and 4.32g of sodium hydroxide. React at 140°C for 12 hours. After washing several times with anhydrous ethanol, place in a vacuum oven and dry overnight at 80°C to obtain product two.

[0114] (3) Stir product one and product two in a mixing container for 2 hours until they are evenly mixed and add an appropriate amount of water. Then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 5 mm. Place them in an oven and dry at 80°C for 4 hours and at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0115] The catalyst exhibited an oxygen desorption capacity of 8.6 mmol / g in the O2-TPD test.

[0116] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 79.8%, and the styrene selectivity was 92.7%.

[0117] Example 8

[0118] (1) Weigh 66 parts of Fe2O3, 9.5 parts of K2O, 4.1 parts of MnO2, and 0.7 parts of TiO2. Stir in a mixing container until the mixture is uniform. After drying, place in a muffle furnace and calcine at 800°C for 5 hours to obtain product one.

[0119] (2) Weigh cerium nitrate equivalent to 10.2 parts CeO2, cobalt acetate equivalent to 5 parts Co3O4, and ammonium tungstate equivalent to 4.5 parts WO3. Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 120.74g diethylene glycol and 4.32g sodium hydroxide. React at 140℃ for 12 hours. After washing several times with anhydrous ethanol, place in a vacuum oven and dry overnight at 80℃ to obtain product two.

[0120] (3) Stir product one and product two in a mixing container for 2 hours until they are evenly mixed and add an appropriate amount of water. Then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 5 mm. Place them in an oven and dry at 80°C for 4 hours and at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0121] The catalyst exhibited an oxygen desorption capacity of 11.1 mmol / g in the O2-TPD test.

[0122] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 82.1%, and the styrene selectivity was 94.0%.

[0123] Comparative Example 1

[0124] Weigh out 65 parts of ferric oxide (Fe2O3), 8.5 parts of potassium carbonate (K2O), 3.1 parts of manganese nitrate (MnO2), and 0.7 parts of titanium dioxide (TiO2), stir them in a mixing container until they are evenly mixed, dry them, and then place them in a muffle furnace and calcine them at 800°C for 5 hours to obtain product one.

[0125] Weigh out cerium nitrate equivalent to 11.2 parts CeO2, cobalt acetate equivalent to 6 parts Co3O4, and ammonium tungstate equivalent to 5.5 parts WO3. Stir in a mixing container until homogeneous, dry, and then calcine in a muffle furnace at 800℃ for 5 hours. Then, take 3g of the calcined sample and immerse it in a solution containing 88mL diethylene glycol and 4.32g sodium hydroxide. React at 140℃ for 12 hours. After washing several times with anhydrous ethanol, dry in a vacuum oven at 80℃ overnight to obtain product two.

[0126] Product 1 and Product 2 were stirred in a mixing container for 2 hours until they were evenly mixed, and an appropriate amount of water was added. Then, they were 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.

[0127] The catalyst exhibited an oxygen desorption capacity of 6.5 mmol / g in the O2-TPD test. 100 mL of the catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and an ethylbenzene space velocity of 1.0 h⁻¹. -1 The performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 77.1%, and the styrene selectivity was 91.3%.

[0128] Comparative Example 2

[0129] Weigh out 65 parts of ferric oxide (Fe2O3), 8.5 parts of potassium carbonate (K2O), 3.1 parts of manganese nitrate (MnO2), 0.7 parts of titanium dioxide (TiO2), 11.2 parts of cerium nitrate (CeO2), 6 parts of cobalt acetate (Co3O4), and 5.5 parts of ammonium tungstate (WO3). Stir in a mixing container until homogeneous. After drying, place in a muffle furnace and calcine at 800℃ for 5 hours.

[0130] Then, 3g of the calcined sample was immersed in a solution containing 120.74g of diethylene glycol and 4.32g of sodium hydroxide, reacted at 140℃ for 12h, washed repeatedly with anhydrous ethanol, and then dried overnight in a vacuum oven at 80℃.

[0131] The product dried in a vacuum oven was stirred in a mixing 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 at 120°C for 10 hours to obtain a monolithic, well-structured finished catalyst.

[0132] The catalyst exhibited an oxygen desorption capacity of 7.8 mmol / g in the O2-TPD test.

[0133] 100 mL of catalyst was loaded into the reactor and incubated at 40 kPa (absolute pressure) and ethylbenzene space velocity 1.0 h⁻¹. -1 Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 78.2%, and the styrene selectivity was 91.6%.

[0134] Comparative Example 3

[0135] Weigh out 65 parts of ferric oxide (Fe2O3), 8.5 parts of potassium carbonate (K2O), 3.1 parts of manganese nitrate (MnO2), and 0.7 parts of titanium dioxide (TiO2), stir them in a mixing container until they are evenly mixed, dry them, and then place them in a muffle furnace and calcine them at 800°C for 5 hours to obtain product one.

[0136] Weigh out cerium nitrate equivalent to 11.2 parts CeO2, cobalt acetate equivalent to 6 parts Co3O4, and ammonium tungstate equivalent to 5.5 parts WO3. Stir in a mixing container until homogeneous, dry, and then calcine in a muffle furnace at 800℃ for 5 hours. Afterward, take 3g of the calcined sample and immerse it in water, reacting at 140℃ for 12 hours. Wash repeatedly with anhydrous ethanol, and then dry in a vacuum oven overnight to obtain product two.

[0137] Product 1 and Product 2 were stirred in a mixing container for 2 hours until homogeneous, and an appropriate amount of water was added. Subsequently, the mixture 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 catalyst showed an oxygen desorption capacity of 5.1 mmol / g in an O2-TPD test. 100 mL of the catalyst was loaded into a reactor and subjected to an ethylbenzene space velocity of 1.0 h⁻¹ at 40 kPa (absolute pressure). -1 Performance was evaluated under the following conditions: temperature 620℃, water ratio 0.8 (wt), and molar ratio of ethylbenzene to O2 5:1. After 100 h of reaction, the ethylbenzene conversion rate reached 76.4%, and the styrene selectivity was 90.5%.

[0138] 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, Based on the total weight of the catalyst, the dehydrogenation catalyst comprises: Fe2O3, K2O, CeO2, Co3O4, group VIB metal oxides, MnO2, and group IVB metal oxides; the oxygen desorption capacity of the dehydrogenation catalyst in the O2-TPD test is greater than 8.2 mmol / g; the Fe2O3 content is 56wt%-74wt%; the K2O content is 5wt%-11wt%; the CeO2 content is 8wt%-13wt%; the group VIB metal oxide content is 4wt%-8.5wt%; the Co3O4 content is 3wt%-7.5wt%; the MnO2 content is 2.1wt%-5.7wt%; and the group IVB metal oxide content is 0.3wt%-1.5wt%.

2. The dehydrogenation catalyst according to claim 1, wherein, The group VIB metal oxides are WO3 and / or MoO3; the group IVB metal oxides are TiO2 and / or ZrO2.

3. The dehydrogenation catalyst according to claim 1 or 2, wherein, The group VIB metal oxide is WO3; the group IVB metal oxide is TiO3.

4. The method for preparing the dehydrogenation catalyst according to any one of claims 1-3, characterized in that, The method includes: (1) After mixing Fe source, K source, Mn source and IVB group metal source, the mixture is first dried and then first calcined; (2) After mixing Ce source, Co source and VIB group metal source, the mixture is dried and calcined to obtain calcined product. The calcined product is mixed with a solution containing polyol and alkali and subjected to solvothermal reduction reaction. Then it is washed with alcohol and dried under vacuum or in an inert gas atmosphere. (3) Mix the products obtained in steps (1) and (2) and shape them; The mass ratio of the calcined product, polyol, and alkali is 1:(35.8-44.2):(1.06-1.75).

5. The preparation method according to claim 4, wherein, In step (2), the mass ratio of the calcined product to the polyol is 1:(37.2-42.6); and / or The mass ratio of roasted product to alkali is 1:(1.18-1.65); and / or The solvothermal reduction reaction conditions include: a temperature of 140-180 ℃; and / or a reaction time of 10-15 h.

6. The preparation method according to claim 5, wherein, The solvothermal reduction heating rate is 10-15℃ / min.

7. The preparation method according to claim 4 or 5, wherein, In step (2), the polyol is selected from C2-C5 polyols; the base is selected from at least one of alkali metal hydroxide and ammonia water.

8. The preparation method according to claim 4 or 5, wherein, In step (2), the polyol is at least one of diethylene glycol, triethylene glycol, ethylene glycol and propylene glycol; the base is sodium hydroxide.

9. The preparation method according to claim 4 or 5, wherein, In step (2), the polyol is diethylene glycol.

10. The preparation method according to claim 4 or 5, wherein, The Fe source, K source, Ce source, Group VIB metal source, Mn source, Co source, and Group IVB metal source are each oxide of the element and / or salt of the element.

11. The preparation method according to claim 10, wherein, 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 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 group IVB metal source is one or more of ammonium molybdate, ammonium metamolybdate, phosphomolybdic acid, ammonium tungstate, ammonium metatungstate, and phosphotungstic acid; and / or The Co source includes one or more of cobalt nitrate, cobalt acetate, cobalt chloride, cobalt sulfate, and cobalt acetylacetone; and / or The Mn source includes one or more of manganese dioxide, manganese chloride, manganese acetate, manganese nitrate, and manganese sulfate; and / or Group IVB metal sources include one or more of titanium dioxide, titanium tetrachloride, titanium sulfate, zirconium dioxide, zirconium tetrachloride, and zirconium sulfate.

12. The use of the dehydrogenation catalyst according to any one of claims 1-3 in the dehydrogenation of alkyl aromatics to prepare alkenyl aromatics.

13. A method for dehydrogenating alkylbenzene, characterized in that, The method includes: Alkenylbenzene is prepared by contacting alkylbenzene with water in the presence of a catalyst and oxygen to carry out a dehydrogenation reaction. The catalyst includes the dehydrogenation catalyst according to any one of claims 1-3.

14. The method according to claim 13, wherein, The molar ratio of alkylbenzene to oxygen is 4-6.5:1; and / or Water to mass ratio 0.5-1.0; and / or The space velocity of alkylbenzenes is 0.2-2.0 h⁻¹. -1 ; and / or The dehydrogenation reaction conditions include a temperature of 550-650 ℃ and an absolute pressure of 20-100 kPa.

15. The method according to claim 13, wherein, Alkylbenzene is ethylbenzene.

Images