Process for the production of divinylbenzene by dehydrogenation of diethylbenzene

Abstract

This invention relates to a method for producing divinylbenzene by dehydrogenation of diethylbenzene. The method includes: contacting a diethylbenzene-containing feedstock with a dehydrogenation catalyst in the presence of water vapor to carry out a dehydrogenation reaction, thereby obtaining a product containing divinylbenzene; the dehydrogenation catalyst includes Fe2O3, K2O, CeO2, MoO3, and CaO; wherein the exposed crystal surface area of ​​CeO2 (100) accounts for more than 65% of the total exposed crystal surface area of ​​CeO2. The catalyst of this method exhibits high catalytic activity and divinylbenzene selectivity in the production of divinylbenzene under low water ratio conditions.

Description

Technical Field

[0001] This invention relates to a method for producing divinylbenzene by dehydrogenation of diethylbenzene, specifically a method for producing divinylbenzene by dehydrogenation of diethylbenzene under low water ratio conditions. Background Technology

[0002] Divinylbenzene is an important crosslinking agent widely used in ion exchange resins, ion exchange membranes, ABS resins, polystyrene resins, unsaturated polyester resins, synthetic rubbers, specialty plastics, coatings, adhesives, and other fields. There are many methods for preparing divinylbenzene, but the industrial production method mainly involves the dehydrogenation of divinylbenzene.

[0003] The diethylbenzene dehydrogenation reaction is a strongly endothermic and reversible reaction involving an increase in the number of molecules, favored by high temperature and low pressure. Industrially, a large amount of high-temperature steam is typically introduced to facilitate the formation of the target product, divinylbenzene. Steam plays several important roles in the reaction: providing the heat required for the reaction; reducing the partial pressure of diethylbenzene, promoting the shift of chemical equilibrium towards the product; eliminating carbon buildup on the catalyst surface; and oxidizing the catalyst surface to maintain its activity. However, using large amounts of superheated steam as the dehydrogenation medium results in high energy consumption, large product condensation, and high production costs. Therefore, the diethylbenzene dehydrogenation process aims to achieve a high divinylbenzene yield with a low water ratio (the mass ratio of steam to diethylbenzene in the feed). Adopting a low water ratio operation is one of the important measures for energy saving and consumption reduction. Furthermore, the dehydrogenation of diethylbenzene to divinylbenzene is a series reaction of two reversible steps: the dehydrogenation of diethylbenzene to ethylstyrene (monoene) and the further dehydrogenation of ethylstyrene to divinylbenzene (diene). The dehydrogenation products often contain a high concentration of ethylstyrene. Therefore, reducing the ratio of monoene to diene in the products is also an important means to improve the economic efficiency of the production process.

[0004] Most existing diethylbenzene dehydrogenation catalysts are Fe-K-Ce based catalysts, with Fe-K oxides as the main active components and Ce as the main promoter. They also contain structural stabilizers and electronic aids such as oxides of Mg, Mo, W, and Ca. The published world patent WO2008090974 (High-strength catalyst for alkyl aromatic hydrocarbon dehydrogenation, its preparation method and application) uses 0.5–5 micrometer cerium hydroxide as a raw material. Increasing the cerium content can effectively improve the mechanical strength and performance of the catalyst, making it suitable for industrial production of alkyl aromatic hydrocarbon dehydrogenation. CN111056909A discloses a method for continuously reacting diethylbenzene with two different iron-potassium-cerium based catalysts in a fixed-bed reactor, achieving high diethylbenzene conversion and a low mono- and diene ratio. However, the water vapor / ethylbenzene weight ratio is high, ranging from 2.0 to 5.0.

[0005] Existing production processes for divinylbenzene dehydrogenation still suffer from high steam consumption and high energy consumption. Developing catalysts and production processes suitable for low water ratios, and improving the selectivity of divinylbenzene to reduce production costs, has become an urgent need for divinylbenzene producers. Summary of the Invention

[0006] The technical problem this invention aims to solve is the high water vapor consumption, high mono- and diene ratio, and low divinylbenzene selectivity in existing diethylbenzene dehydrogenation technologies. This invention provides a method for producing divinylbenzene via diethylbenzene dehydrogenation. The catalyst used in this method exhibits high catalytic activity and divinylbenzene selectivity under low water ratio conditions.

[0007] This invention provides a method for producing divinylbenzene by dehydrogenation of diethylbenzene. The method includes: contacting a diethylbenzene-containing feedstock with a dehydrogenation catalyst in the presence of water vapor to carry out a dehydrogenation reaction, thereby obtaining a product containing divinylbenzene; the dehydrogenation catalyst includes Fe2O3, K2O, CeO2, MoO3, and CaO; wherein the exposed crystal surface area of ​​CeO2 (100) accounts for more than 65% of the total exposed crystal surface area of ​​CeO2, preferably 65% ​​to 90%.

[0008] In the above technical solution, the application of the dehydrogenation catalyst in the dehydrogenation of diethylbenzene to produce divinylbenzene is suitable for low water ratios, that is, the weight ratio of water / diethylbenzene is below 2.0, preferably 1.2 to 2.0.

[0009] In the above technical solution, the water is preheated into water vapor before entering the reactor and then fully mixed with the raw material gas.

[0010] In the above technical solution, the outlet pressure of the reaction bed is 20-80 kPa, preferably 20-50 kPa; the pressure is absolute pressure; the outlet temperature of the reaction bed is 560℃-620℃.

[0011] In the above technical solution, the mass hourly space velocity (MSV) of diethylbenzene is 0.2–2.0 h⁻¹. -1 .

[0012] In the above technical solution, the dehydrogenation catalyst, based on the total mass of the dehydrogenation catalyst, comprises the following components by mass fraction:

[0013] (a) 61%–86% Fe2O3;

[0014] (b) 5%–14% K₂O;

[0015] (c) 6%–14% CeO2;

[0016] (d) 0.5%–5% MoO3;

[0017] (e) 0.3% to 7% CaO.

[0018] In the above technical solution, preferably, based on the total mass of the dehydrogenation catalyst, the dehydrogenation catalyst contains 0.01% to 2.0% Na2O by mass fraction.

[0019] In the above technical solution, based on the total mass of the dehydrogenation catalyst, the dehydrogenation catalyst may also contain 0.01% to 2.0% TiO2 and other metal oxides by mass fraction.

[0020] In the above technical solution, preferably, the exposed crystal surface area of ​​CeO2(100) accounts for more than 70% of the total exposed crystal surface area of ​​CeO2; for example, but not limited to 70%, 75%, 80%, 85%, 87%, 90%, etc.

[0021] The preparation method of the dehydrogenation catalyst in the above technical solution includes the following steps:

[0022] The Fe source, Ce source, Mo source, Ca source, optional first K source, and optional porogen are mixed evenly, then an alkaline solution is added, the mixture is allowed to stand and react, shaped, and calcined to obtain the dehydrogenation catalyst.

[0023] The K2O in the dehydrogenation catalyst originates from the first K source and / or an alkaline solution.

[0024] In the above technical solution, in the preparation method of the dehydrogenation catalyst, the alkaline solution is an aqueous solution of potassium hydroxide and / or sodium hydroxide, preferably an aqueous solution of sodium hydroxide and potassium hydroxide. When the alkaline solution is an aqueous solution of sodium hydroxide and potassium hydroxide, the mass ratio of sodium hydroxide (based on Na₂O) to potassium hydroxide (based on K₂O) is preferably 1:2 to 23. The concentration of hydroxide ions in the alkaline solution is 1 mol / L to 8 mol / L. In the preparation method of the dehydrogenation catalyst, the amount of alkaline solution is sufficient to ensure that the cerium source dissolves in the liquid phase for reaction.

[0025] In the above technical solution, in the preparation method of the dehydrogenation catalyst, the K2O in the dehydrogenation catalyst originates from a first K source and / or an alkaline solution. Preferably, at least part of the K2O in the dehydrogenation catalyst originates from an alkaline solution containing K. Preferably, at least 50% of the K2O in the dehydrogenation catalyst originates from a K-containing alkaline solution, and the remainder originates from the first K source. Alternatively, all the K2O in the dehydrogenation catalyst may originate from a K-containing alkaline solution, without using a first K source.

[0026] In the above technical solution, in the preparation method of the dehydrogenation catalyst, the Fe source is added in the form of Fe2O3 oxide. The Fe source is preferably selected from iron oxide red and / or iron oxide yellow, more preferably a combination of iron oxide red and iron oxide yellow, wherein the mass ratio of iron oxide red and iron oxide yellow, based on Fe2O3, is 1.0–3.5:1. The first K source is added in the form of a potassium salt; the potassium salt is selected from any one or more of potassium carbonate, potassium nitrate, and potassium bicarbonate. The Ce source is added in the form of a cerium salt; the cerium salt is cerium nitrate. The Mo source is added in the form of a molybdenum salt or oxide; the molybdenum salt is ammonium molybdate. The calcium source is added in the form of an oxide or hydroxide. The pore-forming agent is any one or more of activated carbon, graphite, sodium carboxymethyl cellulose, and polystyrene microspheres. The amount of pore-forming agent added is less than 5% of the mass of the dehydrogenation catalyst, further being 0.01%–5%. In the preparation method of the dehydrogenation catalyst, the Fe source, Ce source, Mo source, Ca source, first K source, and pore-forming agent are all added in the form of solid-phase powder.

[0027] In the above technical solution, the preparation method of the dehydrogenation catalyst further includes a Ti source in the raw materials; the Ti source, Fe source, Ce source, Mo source, Ca source, optional first K source, and optional pore-forming agent are mixed and added uniformly. The Ti source is added in the form of a titanium salt or oxide; the titanium salt is any one or both of titanium tetrachloride and titanium tetrabromide.

[0028] In the above technical solution, the mixing in the preparation method of the dehydrogenation catalyst can be carried out by conventional mechanical stirring.

[0029] In the above technical solution, the preparation method of the dehydrogenation catalyst involves a static reaction at 120–180°C for 12–48 hours. The preferred vessel for the static reaction is an autoclave. No special limitations are placed on the pressure of the static reaction.

[0030] In the above technical solution, the preparation method of the dehydrogenation catalyst can be achieved by extrusion molding, and the strip shape can be particles with a diameter of 2-5 mm and a length of 3-10 mm. If the material after reaction cannot meet the molding requirements, some moisture can be removed by evaporation or other methods, or an appropriate amount of moisture can be added before molding.

[0031] In the above technical solution, the preparation method of the dehydrogenation catalyst involves calcination at a temperature of 600–1000°C for 2–8 hours.

[0032] In the above technical solution, the preparation method of the dehydrogenation catalyst employs a two-step calcination process as a preferred calcination condition, for example, but not limited to, calcination at 600–800°C for 2–4 hours, followed by calcination at 900–1000°C for 2–4 hours. The calcination is carried out in a muffle furnace.

[0033] In the above technical solution, the preparation method of the dehydrogenation catalyst may include a drying step before calcination of the shaped material. The drying temperature is 50–200°C, and the drying time is 1–24 hours.

[0034] Compared with the prior art, the present invention has significant advantages and outstanding effects, as follows:

[0035] 1. In the dehydrogenation reaction of diethylbenzene, the surface of the dehydrogenation catalyst is covered by H after capturing H from alkylbenzene molecules, and the surface is reduced, requiring the removal of H2 to restore reaction activity. The rate of H2 removal on the active phase potassium ferrite surface in the Fe-K-Ce-Mo dehydrogenation catalyst is low, which limits the reaction activity of the dehydrogenation catalyst. H on the surface of the active phase of the dehydrogenation catalyst can migrate to the CeO2 surface with the promotion of water, quickly forming H2 and detaching from the surface of the dehydrogenation catalyst, reducing the reaction energy barrier, promoting the reaction, and improving the catalytic activity of the dehydrogenation catalyst. The inventors found that the reaction performance of the Fe-K-Ce-Mo diethylbenzene dehydrogenation catalyst is highly correlated with its surface structure, and different CeO2 exposed crystal faces lead to significant differences in the dehydrogenation activity and stability of the catalyst. Further research by the inventors found that a high proportion of CeO2(100) exposed crystal facet area, especially above 65%, promotes the re-oxidation of active sites in the dehydrogenation reaction of the catalyst, and, in combination with promoters, increases the reduction temperature of the catalyst, giving the catalyst good activity.

[0036] 2. In this invention, the inventors discovered that by controlling the alkalinity of the system and the wet reaction conditions during the preparation of the Fe-K-Ce-Mo diethylbenzene dehydrogenation catalyst, a high proportion of CeO2(100) exposed crystal faces on the catalyst surface is achieved. Furthermore, this preparation method promotes the interaction between the promoter components and the active components, thereby improving the stability of the crystal structure in the catalyst. Compared to conventional dry preparation methods, this method is more beneficial for improving the catalytic performance of the diethylbenzene dehydrogenation catalyst. The catalyst preparation process is simple, and the resulting catalyst has the advantages of high activity and high selectivity for diethylbenzene.

[0037] 3. The dehydrogenation of diethylbenzene to divinylbenzene is a series reaction of two reversible steps: the dehydrogenation of diethylbenzene to ethylstyrene (monoene) and the further dehydrogenation of ethylstyrene to divinylbenzene (diene). Thermodynamic analysis shows that, under the same conditions, the equilibrium conversion rates of the two dehydrogenation reactions are relatively close. Due to limitations in reaction conditions and the performance of the dehydrogenation catalyst, the dehydrogenation product tends to contain a high concentration of ethylstyrene. To improve the conversion rate of diethylbenzene and the selectivity of the target product divinylbenzene, industrially, a large amount of water vapor (water / diethylbenzene weight ratio ≥ 2.5) is usually introduced into the reaction system to shift the reaction equilibrium towards dehydrogenation. This invention, targeting the characteristics of the reaction, improves the equilibrium conversion rate by appropriately controlling the pressure and temperature at the reaction bed outlet. Furthermore, it employs a high-performance catalyst to achieve high conversion rates in both dehydrogenation steps, significantly reducing the amount of water vapor used and improving both the conversion rate of diethylbenzene and the selectivity of the target product divinylbenzene, achieving better technical results.

[0038] Using the technical solution of this invention, the dehydrogenation catalyst of this invention is evaluated for activity in an adiabatic fixed bed, with an outlet pressure of 30 kPa (absolute pressure) and a diethylbenzene mass hourly space velocity of 1.0 h⁻¹. -1 Evaluation was conducted under the conditions of a bed outlet temperature of 600℃ and a water ratio of 1.8 (by weight). The conversion rate reached over 75%, the total selectivity for ethyl vinylbenzene + divinylbenzene reached over 91%, and the selectivity for divinylbenzene reached over 61%. This indicates that the method for producing divinylbenzene from diethylbenzene under low water ratio conditions has achieved good technical results. Attached Figure Description

[0039] Figure 1 The main exposed crystal planes of the dehydrogenation catalyst in Example 1 were obtained using HAADF-STEM testing.

[0040] Figure 2 The main exposed crystal planes of the dehydrogenation catalyst in Comparative Example 1 were obtained from HAADF-STEM testing. Detailed Implementation

[0041] The present invention will be further illustrated by the following embodiments, but the scope of protection of the present invention is not limited by the embodiments.

[0042] In this invention, the exposed crystal surface area was characterized using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The instrument used was a Titan Cubed Themis G2 300 transmission electron microscope with double spherical aberration correction from FEI. The proportion of the CeO2 (100) crystal surface to the total exposed crystal surface area of ​​CeO2 was obtained by statistical calculation based on the HAADF-STEM morphology images and geometric characteristics of the catalyst sample, which is the proportion of the observed CeO2 (100) crystal surface area to the total observed CeO2 exposed crystal surface area. The total exposed crystal surface area of ​​CeO2 is the sum of the exposed crystal surface areas of CeO2 (100), CeO2 (110), CeO2 (111), and CeO2 (311). By observing the exposed crystal plane of CeO2(100) using a scanning transmission electron microscope, two mutually perpendicular directions

[020] and

[002] can be seen in a plane perpendicular to the observation direction of

[100] , with a crystal plane spacing of 260 to 290 pm, proving that the exposed crystal plane is CeO2(100).

[0043] In this invention, the performance evaluation of the dehydrogenation catalyst of this invention in the diethylbenzene dehydrogenation reaction in an adiabatic fixed bed is briefly described as follows:

[0044] The reactor is a 1” stainless steel tube filled with 50–150 mL of dehydrogenation catalyst with a diameter of 3–10 mm. Deionized water and diethylbenzene are separately metered into a preheating mixer, preheated and mixed into a gaseous state before entering the reactor. The reactor is heated by an electric heating wire to reach a predetermined temperature. The reactants flowing out of the reactor are condensed in water and their composition is analyzed by gas chromatography.

[0045] The water ratio (wt) is the ratio of the weight of water vapor input to the weight of diethylbenzene input per unit time, that is, the ratio of the weight flow rate of water vapor to the weight flow rate of diethylbenzene.

[0046] Diethylbenzene conversion, ethylvinylbenzene selectivity, divinylbenzene selectivity, and dimonene ratio are calculated using the following formulas:

[0047]

[0048]

[0049]

[0050] Total selectivity of di-monoenes % = Selectivity of ethylstyrene % + Selectivity of divinylbenzene %

[0051] Ethylvinylbenzene yield % = diethylbenzene conversion % × ethylvinylbenzene selectivity %

[0052] Divinylbenzene yield % = Diethylbenzene conversion % × Divinylbenzene selectivity %

[0053]

[0054]

Example 1

[0055] Weigh out the following amounts: 50.1 parts of iron oxide red (Fe₂O₃), 21.4 parts of iron oxide yellow (Fe₂O₃), 10.5 parts of cerium nitrate (CeO₂), 2.8 parts of ammonium molybdate (MoO₃), 3.2 parts of calcium oxide, and 3.05 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (0.8 parts of Na₂O) and KOH (11.2 parts of K₂O), with a hydroxide concentration of 3.2 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0056] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100 h of reaction are listed in Table 1. The test results after 1000 h of reaction are listed in Table 2.

[0057]

Example 2

[0058] Weigh out the following amounts: 36.2 parts of iron oxide red (Fe₂O₃), 26.6 parts of iron oxide yellow (Fe₂O₃), 11.6 parts of cerium nitrate (CeO₂), 4.8 parts of ammonium molybdate (MoO₃), 5.4 parts of calcium oxide, and 2.6 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (1.8 parts of Na₂O) and KOH (13.6 parts of K₂O), with a hydroxide concentration of 6.5 mol / L. Allow the mixture to react at 120°C for 48 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0059] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0060]

Example 3

[0061] Weigh out the following amounts: 45.6 parts of iron oxide red (Fe₂O₃), 23.8 parts of iron oxide yellow (Fe₂O₃), 13.8 parts of cerium nitrate (CeO₂), 3.6 parts of ammonium molybdate (MoO₃), and 1.5 parts of calcium oxide. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of 0.9 parts of NaOH (Na₂O) and 10.8 parts of KOH (K₂O), with a hydroxide concentration of 2.5 mol / L. Allow the mixture to react at 170°C for 12 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0062] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0063]

Example 4

[0064] Weigh out the following amounts: 49.2 parts of iron oxide red (Fe₂O₃), 34.9 parts of iron oxide yellow (Fe₂O₃), 8.3 parts of cerium nitrate (CeO₂), 1.2 parts of ammonium molybdate (MoO₃), 0.4 parts of calcium oxide, and 4.8 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (0.8 parts of Na₂O) and KOH (5.2 parts of K₂O), with a hydroxide concentration of 2.0 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 600°C for 4 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0065] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0066]

Example 5

[0067] Weigh out the following amounts: 52.3 parts of iron oxide red (Fe₂O₃), 28.0 parts of iron oxide yellow (Fe₂O₃), 8.1 parts of cerium nitrate (CeO₂), 0.6 parts of ammonium molybdate (MoO₃), 2.6 parts of calcium oxide, and 2.5 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (1.0 part of Na₂O) and KOH (7.4 parts of K₂O), with a hydroxide concentration of 2.6 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 750°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0068] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0069]

Example 6

[0070] Weigh out the following amounts: 50.6 parts of iron oxide red (Fe₂O₃), 20.3 parts of iron oxide yellow (Fe₂O₃), 6.9 parts of cerium nitrate (CeO₂), 3.5 parts of ammonium molybdate (MoO₃), 6.9 parts of calcium oxide, 0.06 parts of titanium dioxide, and 2.6 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (0.6 parts of Na₂O) and KOH (11.14 parts of K₂O), with a hydroxide concentration of 3.1 mol / L. React in an autoclave at 140°C for 20 hours. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine in a muffle furnace at 650°C for 2 hours, then at 980°C for 2 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0071] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0072]

Example 7

[0073] Weigh out the following amounts: 54.4 parts of iron oxide red (Fe₂O₃), 16.0 parts of iron oxide yellow (Fe₂O₃), 11.2 parts of cerium nitrate (CeO₂), 3.0 parts of MoO₃, 3.2 parts of calcium carbonate (CaO), and 3.1 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (1.6 parts of Na₂O) and KOH (10.6 parts of K₂O), with a hydroxide concentration of 3.0 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 50°C for 12 hours and then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0074] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100 h of reaction are listed in Table 1. The test results after 1000 h of reaction are listed in Table 2.

[0075]

Example 8

[0076] Weigh out the following amounts: 37.5 parts of iron oxide red (Fe₂O₃), 35.1 parts of iron oxide yellow (Fe₂O₃), 11.9 parts of cerium nitrate (CeO₂), 2.1 parts of ammonium molybdate (MoO₃), 3.3 parts of calcium nitrate (CaO), and 3.5 parts of activated carbon. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (1.5 parts of Na₂O) and KOH (8.6 parts of K₂O), with a hydroxide concentration of 2.8 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 100°C for 4 hours and then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0077] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0078]

Example 9

[0079] Weigh out the following amounts: 40.0 parts of iron oxide red (Fe₂O₃), 32.5 parts of iron oxide yellow (Fe₂O₃), 10.6 parts of cerium nitrate (CeO₂), 2.1 parts of ammonium molybdate (MoO₃), 2.9 parts of calcium chloride (CaO), and 3.2 parts of graphite. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of 0.5 parts of NaOH (Na₂O) and 11.4 parts of KOH (K₂O), with a hydroxide concentration of 3.5 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 120°C for 4 hours and then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0080] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0081]

Example 10

[0082] Weigh out the following amounts: 50.5 parts of iron oxide red (Fe₂O₃), 19.7 parts of iron oxide yellow (Fe₂O₃), 12.0 parts of cerium nitrate (CeO₂), 2.6 parts of MoO₃, 3.5 parts of calcium oxide, and 3.2 parts of hydroxymethyl cellulose. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (1.1 parts of Na₂O) and KOH (10.6 parts of K₂O), with a hydroxide concentration of 3.4 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 180°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0083] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0084]

Example 11

[0085] Weigh out the following amounts: 50.9 parts of iron oxide red (Fe₂O₃), 23.4 parts of iron oxide yellow (Fe₂O₃), 11.2 parts of cerium nitrate (CeO₂), 1.8 parts of ammonium molybdate (MoO₃), 2.7 parts of calcium carbonate (CaO), and 3.2 parts of graphite. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (0.5 parts of Na₂O) and KOH (9.5 parts of K₂O), with a hydroxide concentration of 2.9 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 200°C for 2 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0086] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0087]

Example 12

[0088] Weigh out the following amounts: 50.1 parts of iron oxide red (Fe₂O₃), 21.4 parts of iron oxide yellow (Fe₂O₃), 10.5 parts of cerium nitrate (CeO₂), 9.6 parts of potassium nitrate (K₂O), 2.8 parts of ammonium molybdate (MoO₃), 3.2 parts of calcium oxide, and 3.05 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of NaOH (0.8 parts of Na₂O) and KOH (1.6 parts of K₂O), with a hydroxide ion concentration of 3.2 mol / L. Let the mixture stand at 140°C for 20 hours in an autoclave. Next, the water content of the above mixture was adjusted, and the mixture was extruded and granulated to obtain particles with a diameter of 3 mm and a length of 6 mm. The particles were placed in an oven and dried at 80°C for 4 hours and 150°C for 4 hours. Then, they were placed in a muffle furnace and calcined at 650°C for 2 hours and 900°C for 2 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0089] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100 h of reaction are listed in Table 1. The test results after 1000 h of reaction are listed in Table 2.

[0090]

Example 13

[0091] Weigh out the following amounts: 50.1 parts of iron oxide red (Fe₂O₃), 21.4 parts of iron oxide yellow (Fe₂O₃), 10.5 parts of cerium nitrate (CeO₂), 11.2 parts of potassium carbonate (K₂O), 2.8 parts of ammonium molybdate (MoO₃), 3.2 parts of calcium oxide, and 3.05 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add 0.8 parts of Na₂O in NaOH aqueous solution, with a hydroxide concentration of 3.2 mol / L. React in an autoclave at 140°C for 20 hours. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine in a muffle furnace at 650°C for 2 hours, then at 900°C for 2 hours to obtain the finished dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0092] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0093]

Example 14

[0094] Weigh out the following amounts: 50.1 parts of iron oxide red (Fe₂O₃), 21.4 parts of iron oxide yellow (Fe₂O₃), 10.5 parts of cerium nitrate (CeO₂), 2.8 parts of ammonium molybdate (MoO₃), 3.2 parts of calcium oxide, 0.8 parts of sodium nitrate (Na₂O), and 3.05 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add an aqueous solution of KOH (11.2 parts of K₂O), with a hydroxide concentration of 3.2 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0095] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100 h of reaction are listed in Table 1. The test results after 1000 h of reaction are listed in Table 2.

[0096]

Example 15

[0097] Weigh out the following amounts: 50.1 parts of iron oxide red (Fe₂O₃), 21.4 parts of iron oxide yellow (Fe₂O₃), 10.5 parts of cerium nitrate (CeO₂), 2.8 parts of ammonium molybdate (MoO₃), 3.2 parts of calcium oxide, and 3.05 parts of polystyrene microspheres. Stir in a mixer for 2 hours until homogeneous. Then add a mixed aqueous solution of KOH (11.2 parts of K₂O), with a hydroxide concentration of 3.2 mol / L. Allow the mixture to react at 140°C for 20 hours in an autoclave. Adjust the water content of the mixture, then extrude and granulate to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours and then at 900°C for 2 hours to obtain the final dehydrogenation catalyst. The composition of the dehydrogenation catalyst is listed in Table 1.

[0098] 100 mL of dehydrogenation catalyst was loaded into the reactor, with the reaction bed outlet pressure at 30 kPa (absolute pressure) and the diethylbenzene mass hourly space velocity (WHSV) at 1.0 h⁻¹. -1 The performance was evaluated under the conditions of a reaction bed outlet temperature of 600℃ and a water ratio of 1.8 (wt). The test results after 100h of reaction are listed in Table 1.

[0099] Comparative Example 1

[0100] Weigh out the following amounts: 50.1 parts of iron oxide red (Fe₂O₃), 21.4 parts of iron oxide yellow (Fe₂O₃), 10.5 parts of cerium nitrate (CeO₂), 11.2 parts of potassium carbonate (K₂O), 2.8 parts of ammonium molybdate (MoO₃), 4.0 parts of calcium oxide, and 3.05 parts of polystyrene microspheres. Add the same amount of water as in Example 1 to a mixer and stir for 2 hours until homogeneous. Let stand in an autoclave at 140°C for 20 hours. Then, extrude and granulate the mixture to obtain particles with a diameter of 3 mm and a length of 6 mm. Dry these particles in an oven at 80°C for 4 hours, then at 150°C for 4 hours. Finally, calcine them in a muffle furnace at 650°C for 2 hours, then at 900°C for 2 hours to obtain the finished dehydrogenation catalyst. The evaluation method for the dehydrogenation catalyst is the same as in Example 1. The test results and the composition of the dehydrogenation catalyst are listed in Tables 1 and 2.

[0101] Table 1. Composition, properties, and evaluation results of the dehydrogenation catalysts in the examples and comparative examples.

[0102]

[0103]

[0104] Note: *Reaction data after 100 hours of reaction at a water ratio of 1.8;

[0105] **Crystal plane ratio: The proportion of CeO2(100) exposed crystal plane area to the total exposed crystal plane area of ​​CeO2 in the dehydrogenation catalyst.

[0106] Table 2. Stability evaluation results of dehydrogenation catalysts in the examples and comparative examples.

[0107]

[0108]

[0109] from Figure 1 , Figure 2 It can be seen that the main exposed crystal plane of CeO2 in the dehydrogenation catalyst of Example 1 is the CeO2(100) crystal plane. In the dehydrogenation catalyst of Comparative Example 1, the main exposed crystal plane of CeO2 is the CeO2(111) crystal plane, and the CeO2(111) crystal plane accounts for 52% of the total exposed crystal planes of CeO2. Combined with the results in Tables 1 and 2, it can be seen that the catalyst of the present invention has high activity and divinylbenzene selectivity, good stability, and after the dehydrogenation reaction has been running for a long time of 1000h, the divinylbenzene conversion rate and divinylbenzene selectivity have not decreased significantly.

[0110] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing divinylbenzene by dehydrogenation of diethylbenzene, the method comprising: Diethylbenzene-containing feedstock undergoes a dehydrogenation reaction in the presence of steam with a dehydrogenation catalyst to obtain a product containing divinylbenzene; The dehydrogenation catalyst, based on its total mass, contains the following components by mass fraction: (a) 61%~86% Fe2O3; (b) 5%~14% K2O; (c) 6%~14% CeO2; (d) 0.5%~5% MoO3; (e) 0.3%~7% CaO; Among them, the exposed crystal surface area of ​​CeO2(100) accounts for 65% to 80% of the total exposed crystal surface area of ​​CeO2.

2. The method according to claim 1, characterized in that, The dehydrogenation reaction is suitable for dehydrogenation reactions with a low water ratio; the low water ratio is below 2.

0. And / or, the reaction bed outlet pressure is 20~80 kPa; the pressure is absolute pressure; the reaction bed outlet temperature is 560°C. o C~620 o C; And / or, the mass hourly space velocity (MSV) of diethylbenzene is 0.2–2.0 h⁻¹. -1 .

3. The method according to claim 2, characterized in that, The low water ratio is 1.2~2.0; And / or, the outlet pressure of the reaction bed is 20~50kPa.

4. The method according to claim 1, characterized in that, Based on the total mass of the dehydrogenation catalyst, the dehydrogenation catalyst contains 0.01%~2.0% Na2O by mass fraction; And / or, based on the total mass of the dehydrogenation catalyst, the dehydrogenation catalyst further contains 0.01% to 2.0% TiO2 by mass fraction.

5. The method according to any one of claims 1 and 4, characterized in that, The method for preparing the dehydrogenation catalyst includes the following steps: The Fe source, Ce source, Mo source, Ca source, optional first K source, and optional porogen are mixed evenly, then an alkaline solution is added, the mixture is allowed to stand and react, shaped, and calcined to obtain the dehydrogenation catalyst. The K2O in the dehydrogenation catalyst originates from the first K source and / or an alkaline solution.

6. The method according to claim 5, characterized in that, In the preparation method of the dehydrogenation catalyst, the alkaline solution is an aqueous solution of potassium hydroxide and / or sodium hydroxide; the concentration of hydroxide ions in the alkaline solution is 1 mol / L to 8 mol / L.

7. The method according to claim 6, characterized in that, In the preparation method of the dehydrogenation catalyst, the alkaline solution is an aqueous solution of sodium hydroxide and potassium hydroxide, and the mass ratio of sodium hydroxide (calculated as Na2O) to potassium hydroxide (calculated as K2O) is 1:2~23.

8. The method according to claim 5, characterized in that, The K2O in the catalyst is at least partially derived from an alkaline solution.

9. The method according to claim 8, characterized in that, At least 50% of the K2O in the catalyst originates from a K-containing alkaline solution, with the remainder originating from a first K source.

10. The method according to claim 5, characterized in that, In the preparation method of the dehydrogenation catalyst, the static reaction conditions are: static reaction at 120~180℃ for 12~48h.

11. The method according to claim 5, characterized in that, In the preparation method of the dehydrogenation catalyst, the calcination temperature is 600~1000℃ and the calcination time is 2~8h.

12. The method according to claim 5, characterized in that, In the preparation method of the dehydrogenation catalyst, the Ce source is added in the form of cerium salt; And / or, the Fe source is added in the form of Fe2O3 oxide; And / or, the first K source is added in the form of a potassium salt; And / or, the Mo source is added in the form of a molybdenum salt or oxide; And / or, the Ca source is added in the form of an oxide or hydroxide.

13. The method according to claim 12, characterized in that, In the preparation method of the dehydrogenation catalyst, the Ce source is cerium nitrate; and / or, the Mo source is ammonium molybdate.

14. The method according to claim 5, characterized in that, In the preparation method of the dehydrogenation catalyst, the raw materials also contain a Ti source; the Ti source is added in the form of a titanium salt or an oxide; the titanium salt is any one or both of titanium tetrachloride or titanium tetrabromide.

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