Molybdenum-bismuth-iron catalyst, preparation method and application thereof, and olefin oxidation method

Abstract

The invention particularly relates to a molybdenum-bismuth-iron catalyst, a preparation method and application thereof and an olefin oxidation method. The general formula of the catalyst component is MoBiaFebXcYdZeQf (Bi4Ti3O12) gOj, wherein X is at least one of an alkaline earth metal element and a group VIII metal element; y is at least one of a VB group metal element, a VIB group metal element and a VA group metal element; z is at least one of alkali metal elements; q is at least one of rare earth elements; the value of a ranges from 0.01 to 0.05; the value of b ranges from 0.1 to 0.5; the value of c ranges from 0.2 to 0.8; the value of d is 0.1 to 0.5; the value of e ranges from 0.01 to 0.03; the value of f ranges from 0.01 to 0.04, and the value of g ranges from 0.5 to 3; and j is the total number of oxygen atoms required for meeting the valence of each element in the catalyst. The molybdenum-bismuth-iron catalyst disclosed by the invention has relatively high reaction activity, can effectively improve the reactant conversion rate, the product selectivity and the target product yield, is particularly suitable for being applied to oxidation reaction, and is particularly suitable for being applied to olefin oxidation.

Description

Technical Field

[0001] This invention relates to a molybdenum-bismuth-iron catalyst, its preparation method and application, and a method for oxidizing olefins. Background Technology

[0002] The selective oxidation of olefins to prepare unsaturated acids is an important chemical process. Industrially, olefins are typically oxidized first to obtain unsaturated aldehydes, and then the unsaturated aldehydes are oxidized to obtain unsaturated acids. This process usually involves a two-stage production, using two reactors and two catalysts under different reaction conditions. In the first stage, the main product is acrolein, with approximately 20% acrylic acid. The active component of the catalyst is a complex Mo / Bi composite oxide system.

[0003] Generally, catalyst improvements mainly focus on enhancing their activity and stability. For example, adding transition metals to the active component can improve reactivity and increase product yield; adding rare earth elements can improve redox capabilities; and adding elements such as Fe, Co, and Ni can suppress Mo sublimation, stabilize the active components, and extend the catalyst's lifespan. Furthermore, due to the intense exothermic reaction, controlling the catalyst bed temperature is crucial. The formation of hot spots not only degrades the catalyst's reactivity but also shortens its lifespan, affecting the stable operation of the equipment.

[0004] It is generally believed that in the first step of the propylene oxidation reaction to produce acrolein, olefins are adsorbed onto the catalyst surface, and an α-H atom is removed by a metal oxide to form a free radical intermediate, which then generates the product through oxygen insertion. In this process, the catalyst undergoes a redox cycle, where the oxygen atom that lost its participation in the insertion reaction is reduced, and then re-oxidized by oxygen in the reaction gas. The active site oxygen atom is replenished through oxygen migration. Therefore, the catalyst is required to have good oxygen migration ability to maintain the catalyst structure and redox balance. Existing technologies generally use transition metal composite oxides such as Mo, V, Bi, Te, Nb, Fe, Co, and Ni. Among them, bismuth molybdate (Bi2(MoO4)3) is the active site for the key step of α-H removal (Catalysis Today 49(1999) 141-153).

[0005] US4224187 and US4248803 propose improving olefin conversion and target product yield by modifying the composition and dosage ratio of catalysts and the catalyst preparation method. This improved catalyst is used for the selective oxidation of isobutylene, but it still suffers from low reaction selectivity; while the isobutylene conversion is as high as 99%, the total yield of methacrolein and methacrylic acid is only 73.6%.

[0006] US6268529 discloses a propylene oxidation catalyst with a propylene conversion rate of 98.1%, an acrolein yield of 65.3%, an acrylic acid yield of 20.8%, and a total yield of only 86.1% for acrolein and acrylic acid.

[0007] CN1564709 improves catalyst performance by adding an organic carboxylic acid to overcome the catalyst inhomogeneity caused by stratification between metal salts during the co-precipitation process. This method is used for the selective oxidation of propylene, achieving a propylene conversion of up to 98.12%, a selectivity of up to 82.53% for acrolein, and a total yield of 91.05% for both acrolein and acrylic acid.

[0008] CN1210511A, CN1283604A, and CN1314331A achieve the goal of controlling reaction hotspots and extending catalyst stability by configuring multiple catalyst layers with gradually increasing reactivity along the reactor axis from the reactant gas inlet to the outlet. However, the structural stability of their catalysts needs further improvement. Summary of the Invention

[0009] To address the shortcomings of existing technologies, one of the technical problems this invention aims to solve is to provide a novel molybdenum-bismuth-iron catalyst. This novel molybdenum-bismuth-iron catalyst has high reactivity and can effectively improve reactant conversion, product selectivity, and target product yield. It is particularly suitable for applications in oxidation reactions, especially in olefin oxidation.

[0010] To achieve the above objectives, a first aspect of the present invention provides a molybdenum-bismuth-iron catalyst, wherein the catalyst components have the general formula MoBi. a Fe b X c Y d Z e Q f (Bi4Ti3O 12 ) g O j Wherein, X is at least one of alkaline earth metals and Group VIII metals; Y is at least one of Group VB metals, Group VIB metals, and Group VA metals; Z is at least one of alkali metals; Q is at least one of rare earth elements; a takes the value of 0.01-0.05; b takes the value of 0.1-0.5; c takes the value of 0.2-0.8; d takes the value of 0.1-0.5; e takes the value of 0.01-0.03; f takes the value of 0.01-0.04; g takes the value of 0.5-3; j is the total number of oxygen atoms required to satisfy the oxidation states of each element in the catalyst.

[0011] A second aspect of the present invention provides a method for preparing the molybdenum-bismuth-iron catalyst of the present invention, the method comprising: preparing Bi4Ti3O12 The slurry was mixed with a solution containing Mo, Bi, Fe, X, Y, Z, and Q sources, and then dried and calcined to obtain a molybdenum-bismuth-iron catalyst.

[0012] A third aspect of the present invention provides a molybdenum-bismuth-iron catalyst prepared by the method of the present invention.

[0013] The fourth aspect of this invention provides the application of the molybdenum-bismuth-iron catalyst described herein in oxidation reactions.

[0014] The fifth aspect of the present invention provides a method for oxidizing olefins, the method comprising: contacting an olefin-containing feed gas with an oxidant in the presence of the molybdenum-bismuth-iron catalyst described in the present invention.

[0015] The molybdenum-bismuth-iron catalyst of this invention exhibits high reactivity, effectively improving reactant conversion, product selectivity, and target product yield. It is speculated that this is because the preparation process of the molybdenum-bismuth-iron catalyst utilizes bismuth titanate (Bi4Ti3O3), which has a similar structure to the key active phase Bi2(MoO4)3. 12 Bi4Ti3O 12 It can promote the formation of the key active phase Bi2(MoO4)3, giving the catalyst higher activity and selectivity. Meanwhile, in a preferred embodiment, using a combination of rare earth elements Ce and La with different ionic radii allows these rare earth elements to enter the molybdate structure, improving oxygen migration and stabilizing the molybdate structure, thereby enhancing the activity of the molybdenum-bismuth-iron catalyst. Detailed Implementation

[0016] 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.

[0017] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0018] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0019] When this specification uses the prefixes "known to those skilled in the art," "prior art," or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those conventionally used in the art at the time the invention was proposed, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0020] It should be noted that the two or more aspects (or embodiments) disclosed in the context of this specification can be arbitrarily combined with each other, and the resulting technical solutions (such as methods or systems) are part of the original disclosure of this specification and also fall within the protection scope of this invention.

[0021] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless being based on weight would not be in accordance with the common understanding of those skilled in the art.

[0022] This invention provides a molybdenum-bismuth-iron catalyst, the catalyst component having the general formula MoBi a Fe b X c Y d Z e Q f (Bi4Ti3O 12 ) g O j Wherein, X is at least one of an alkaline earth metal element and a Group VIII metal element; Y is at least one of a Group VB metal element, a Group VIB metal element, and a Group VA metal element; Z is at least one of an alkali metal element; Q is at least one of a rare earth element; a takes the value of 0.01-0.05; b takes the value of 0.1-0.5; c takes the value of 0.2-0.8; d takes the value of 0.1-0.5; e takes the value of 0.01-0.03; f takes the value of 0.01-0.04; g takes the value of 0.5-3; j is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst. The molybdenum-bismuth-iron catalyst of this invention has high reactivity. Applying this molybdenum-bismuth-iron catalyst to oxidation reactions can effectively improve reactant conversion rate, product selectivity, and target product yield, showing good industrial application prospects.

[0023] In this invention, the catalyst component of the general formula MoBi a Fe b X c Y d Z e Q f (Bi4Ti3O 12 ) g O j In the Bi4Ti3O12 Bi exists in compound form, and the content of Bi element does not include Bi4Ti3O. 12 The content of Bi in the formula is calculated based on the amount of each component.

[0024] In this invention, the Bi4Ti3O 12 The average particle size can be selected over a wide range, as illustrated below, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the Bi4Ti3O 12 The average particle size is 1-20 μm, preferably 1-10 μm. The aforementioned preferred Bi4Ti3O... 12 The molybdenum-bismuth-iron catalyst with a significantly improved average particle size distribution exhibits enhanced activity, effectively increasing reactant conversion, product selectivity, and target product yield, thus demonstrating promising prospects for industrial applications.

[0025] In this invention, catalysts possessing the aforementioned characteristics can achieve the objectives of this invention. The range of X is relatively wide; the following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, X is selected from at least one of Mg, Co, and Ni. Molybdenum-bismuth-iron catalysts composed of the aforementioned elements exhibit high reactivity.

[0026] In this invention, the range of Y is relatively wide. For example, Y is selected from at least one of Nb, W, and Sb. In the embodiments of this invention, Nb and W are used as examples to illustrate the advantages of this invention, but this does not limit the scope of this invention. The molybdenum-bismuth-iron catalyst composed of the aforementioned elements has high reactivity.

[0027] In this invention, the range of Z is relatively wide. The following examples are illustrative but do not limit the scope of the invention. According to a preferred embodiment of the invention, Z is selected from at least one of K, Rb, and Cs. In the embodiments of this invention, K, Rb, and Cs are used as examples to illustrate the advantages of the invention, but these do not limit the scope of the invention. The molybdenum-bismuth-iron catalyst composed of the aforementioned elements exhibits high reactivity.

[0028] In this invention, the range of possible values ​​for Q is relatively wide. The following examples are illustrative but do not limit the scope of the invention. According to a preferred embodiment of the invention, Q is selected from at least one of Ce, La, Nd, and Pr, preferably at least one of Ce, La, and Nd. In this embodiment, Ce and La are used as examples to illustrate the advantages of the invention, but this does not limit the scope of the invention. The molybdenum-bismuth-iron catalyst composed of the aforementioned rare earth elements exhibits high reactivity. Applying this molybdenum-bismuth-iron catalyst to oxidation reactions can effectively improve reactant conversion, product selectivity, and target product yield.

[0029] According to a preferred embodiment of the present invention, Q is selected from Ce and La, and the molar ratio of Ce to La is 2-5, preferably 3-4. By employing the aforementioned combination of rare earth elements Ce and La with different ionic radii, rare earth elements can enter the molybdate structure, improving oxygen migration ability and stabilizing the molybdate structure, thereby increasing the activity and yield of the molybdenum-bismuth-iron catalyst.

[0030] In this invention, 'a' is the molar ratio of Bi to Mo. The range of 'a' is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the value of 'a' is 0.02-0.04.

[0031] In this invention, b is the molar ratio of Fe to Mo. The range of b is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the value of b is 0.2-0.4.

[0032] In this invention, c is the molar ratio of X to Mo, and the range of c is relatively wide; for example, the preferred value of c is 0.4-0.7. The above is illustrative but does not limit the scope of the invention.

[0033] In this invention, d is the molar ratio of Y to Mo, and the range of d is relatively wide; for example, the preferred value of d is 0.2-0.4. The above is illustrative but does not limit the scope of the invention.

[0034] In this invention, e is the molar ratio of Z to Mo. The range of e is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the value of e is 0.01-0.02.

[0035] In this invention, f is the molar ratio of Q to Mo. The range of f is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the value of f is 0.02-0.03.

[0036] In this invention, g is Bi4Ti3O 12 The molar ratio of g to Mo has a wide selectable range, as illustrated below but not limiting the scope of the invention. According to a preferred embodiment of the invention, the value of g is 1-2. The aforementioned preferred Bi4Ti3O is used. 12 The molybdenum-bismuth-iron catalyst with a molar ratio of Mo exhibits high reactivity, effectively improving reactant conversion, product selectivity, and target product yield, and shows promising prospects for industrial application.

[0037] Molybdenum-bismuth-iron catalysts possessing the aforementioned characteristics can all achieve the objectives of this invention, and there are no special requirements for their preparation methods. The following is an illustrative description of one preparation method for the molybdenum-bismuth-iron catalyst of this invention, but it does not limit the scope of this invention. The preparation method of the molybdenum-bismuth-iron catalyst of this invention includes: Bi4Ti3O 12 The slurry was mixed with a solution containing Mo, Bi, Fe, X, Y, Z, and Q sources, and then dried and calcined to obtain a molybdenum-bismuth-iron catalyst.

[0038] In this invention, there are no special requirements for the amount of solvent in the slurry; it is sufficient to ensure thorough mixing of the raw materials. In this embodiment of the invention, the amount of solvent in the slurry is determined by the amount of metal ions in the slurry (excluding Bi4Ti3O). 12 The solvent is added at a concentration of 0.1-1 mmol / (g solvent), but this does not limit the scope of the invention.

[0039] In this invention, there are no special requirements for the order of addition of raw materials in the preparation method of the molybdenum-bismuth-iron catalyst. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the preparation method of the molybdenum-bismuth-iron catalyst includes:

[0040] (1) Bi4Ti3O 12 Add to the first solution containing Mo source and Y source and mix;

[0041] (2) The second solution containing Bi source, Fe source, X source, Z source and Q source is added to the mixture in step (1) to obtain a slurry, which is then dried and calcined to obtain a molybdenum-bismuth-iron catalyst.

[0042] In this invention, there are no special requirements for the Mo source; any water-soluble Mo source can be used. For example, in the embodiments of this invention, ammonium molybdate is used as an example to illustrate the advantages of this invention, but this does not limit the scope of this invention.

[0043] In this invention, there are no special requirements for the Y source; any water-soluble Y source can be used. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Y source is selected from ammonium niobate oxalate and / or ammonium metatungstate.

[0044] In this invention, there are no special requirements for the Bi source; any water-soluble Bi source can be used. For example, in the embodiments of this invention, bismuth nitrate is used as an example to illustrate the advantages of this invention, but this does not limit the scope of this invention.

[0045] In this invention, there are no special requirements for the Fe source; any water-soluble Fe source can be used. For example, in the embodiments of this invention, ferric nitrate is used as an example to illustrate the advantages of this invention, but this does not limit the scope of this invention.

[0046] In this invention, there are no special requirements for the X source; any water-soluble X source can be used. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the X source is selected from cobalt nitrate and / or nickel nitrate.

[0047] In this invention, there are no special requirements for the Z source; any water-soluble Z source can be used. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Z source is selected from at least one of rubidium nitrate, potassium nitrate, and cesium nitrate.

[0048] In this invention, there are no special requirements for the Q source; any water-soluble Q source can be used. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the Q source is selected from cerium nitrate and / or lanthanum nitrate.

[0049] In this invention, there are no special requirements for the mixing method. Conventional mixing methods in the art can achieve the purpose of this invention. In order to mix thoroughly, it can generally be mixed under stirring and appropriately heated, for example, at 50-100°C. In order to speed up the drying process, the slurry can be pre-dried before drying to concentrate it to a viscous state. There are no special requirements for the pre-drying temperature. It is sufficient to concentrate the slurry to a viscous state.

[0050] In this invention, there are no special requirements for the drying temperature. Commonly used drying conditions are applicable to this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the drying temperature is 50-100°C. In this embodiment of the invention, the drying temperature is 100°C as an example to illustrate the advantages of this invention, but it does not limit the scope of this invention.

[0051] In this invention, there are no special requirements for drying time. The specific time is adjusted according to the drying temperature. Commonly used drying times are applicable to this invention, such as 1-16 hours. In this embodiment of the invention, a drying time of 6 hours is used as an example to illustrate the advantages of this invention, but this does not limit the scope of the invention.

[0052] In this invention, there are no special requirements for the roasting temperature. Commonly used roasting conditions are applicable to this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the roasting temperature is 400-650°C. In this embodiment of the invention, the roasting temperature is 550°C as an example to illustrate the advantages of this invention, but it does not limit the scope of this invention.

[0053] In this invention, there are no special requirements for the roasting time. The specific roasting time is adjusted according to the roasting temperature. Commonly used roasting times are applicable to this invention, such as 1-12 hours. In this embodiment of the invention, a roasting time of 2 hours is used as an example to illustrate the advantages of the invention, but this does not limit the scope of the invention.

[0054] In this invention, there are no special requirements for the roasting atmosphere. Commonly used roasting atmospheres can be used in this invention. For example, air is used as the roasting atmosphere in the embodiments of this invention to illustrate the advantages of this invention, but this does not limit the scope of this invention.

[0055] In this invention, there are no special requirements for the solvents of the first and second solutions. Commonly used solvents are suitable for this invention as long as they achieve complete dissolution. In the embodiments of this invention, water is used as an example to illustrate the advantages of this invention, but it does not limit the scope of this invention.

[0056] In this invention, there are no special requirements for the amount of solvent used in the first and second solutions, as long as the raw materials are fully dissolved. In the embodiments of this invention, the solvent for the first solution is added when the concentration of metal ions in the first solution is 0.3-0.5 mmol / (g solvent), and the solvent for the second solution is added when the concentration of metal ions in the second solution is 1-7 mmol / (g solvent), but this does not limit the scope of the invention.

[0057] This invention provides a molybdenum-bismuth-iron catalyst prepared by the method described herein. The molybdenum-bismuth-iron catalyst obtained by the method of this invention exhibits high reactivity, effectively improving reactant conversion, product selectivity, and target product yield, and shows promising prospects for industrial application.

[0058] This invention provides the application of the molybdenum-bismuth-iron catalyst described herein in oxidation reactions, preferably in the oxidation of olefins, and more preferably in the oxidation of C3-C5 α-olefins. Applying the molybdenum-bismuth-iron catalyst of this invention to olefin oxidation reactions can effectively improve reactant conversion, product selectivity, and target product yield.

[0059] The present invention provides a method for oxidizing olefins, the method comprising: reacting an olefin-containing feed gas with an oxidant in the presence of the molybdenum-bismuth-iron catalyst described in the present invention.

[0060] In this invention, the range of olefins is relatively wide. The following is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the olefin is a C3-C5 α-olefin, preferably propylene. In the embodiments of the invention, propylene is used as an example to illustrate the advantages of the invention, but it does not limit the scope of the invention.

[0061] In this invention, the olefin-containing feed gas also includes a dilution gas. There are no special requirements for the dilution gas, and any commonly used dilution gas can be used in this invention. For example, the dilution gas is selected from inert gases and / or water vapor. In this embodiment of the invention, water vapor is used as an example to illustrate the advantages of the invention, but this does not limit the scope of the invention.

[0062] In this invention, there are no special requirements for the oxidant; commonly used oxidants can be used. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the oxidant is selected from one or more oxidizing gases, preferably oxygen and / or air. Air is used as an example in the embodiments of the invention to illustrate the advantages of the invention, but it does not limit the scope of the invention.

[0063] In this invention, the volume ratio of the olefin, dilution gas, and oxidant can be selected within a wide range. The following is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the volume ratio of the olefin, dilution gas, and oxidant is 1:0.5-5:6-8. In the embodiments of the invention, 1:1.5:7.7 is used as an example to illustrate the advantages of the invention, but it does not limit the scope of the invention.

[0064] In this invention, the conditions for the contact reaction can be selected from a wide range. The following is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the contact reaction conditions include a temperature of 300-550°C, preferably 300-380°C. In this embodiment, 315°C is used as an example to illustrate the advantages of the invention, but this does not limit the scope of the invention.

[0065] In this invention, the contact reaction pressure can be selected from a wide range. The following is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the contact reaction pressure is 0.01-0.08 MPa. In this embodiment of the invention, the contact reaction pressure is 0.01 MPa as an example to illustrate the advantages of the invention, but it does not limit the scope of the invention.

[0066] In this invention, the volumetric hourly space velocity (VHSV) of the olefin-containing feed gas can be selected within a wide range, for example, 600-1200 mL / g·h. In this embodiment of the invention, the VHSV of the olefin-containing feed gas is 1100 mL / g·h as an example to illustrate the advantages of the invention, but this does not limit the scope of the invention.

[0067] In this invention, the reaction equipment for the contact reaction has no special requirements; for example, the contact reaction is carried out in a fixed-bed reactor.

[0068] The molybdenum-bismuth-iron catalyst of this invention exhibits high reactivity, effectively improving reactant conversion, product selectivity, and target product yield. It is speculated that this is because the preparation process of the molybdenum-bismuth-iron catalyst utilizes bismuth titanate (Bi4Ti3O3), which has a similar structure to the key active phase Bi2(MoO4)3. 12 Bi4Ti3O 12 It can promote the formation of the key active phase Bi2(MoO4)3, giving the catalyst higher activity and selectivity. Meanwhile, in a preferred embodiment, the combination of rare earth elements Ce and La with different ionic radii allows these rare earth elements to enter the molybdate structure, improving oxygen migration and stabilizing the molybdate structure, thereby increasing the activity and yield of the molybdenum-bismuth-iron catalyst.

[0069] The present invention will be described in detail below through embodiments. In the following embodiments, Bi4Ti3O 12 The average particle size parameter was measured by a laser particle size analyzer.

[0070] Preparation Example 1

[0071] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution; 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.02 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain the second solution; the first solution was heated to 70 °C, and 1.5 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 8 μm) were mixed and stirred until homogeneous; then a second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80 °C until it reached a viscous state. The slurry was then dried at 100 °C for 6 hours, and finally calcined in air at 550 °C for 2 hours to obtain the catalyst MoBi. 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.02 La 0.005 (Bi4Ti3O 12 ) 1.5 O j .

[0072] Preparation Example 2

[0073] Weigh out 1 mol of ammonium molybdate (Mo) and 0.2 mol of ammonium metatungstate (W), and dissolve them in 3000 g of water to obtain the first solution; weigh out 0.02 mol of bismuth nitrate (Bi), 0.4 mol of ferric nitrate (Fe), 0.4 mol of nickel nitrate (Ni), 0.01 mol of potassium nitrate (K), 0.015 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La), and dissolve them in 200 g of water to obtain the second solution; heat the first solution to 70 °C, and add 1 mol of Bi₄Ti₃O₃. 12 (Average particle size 2μm) were mixed and stirred until homogeneous; then the second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80℃ until it reached a viscous state. The slurry was then dried at 100℃ for 6 hours, and finally calcined in air at 550℃ for 2 hours to obtain the catalyst MoBi. 0.02 Fe 0.4 Ni 0.4 W 0.2 K 0.01 Ce 0.015 La 0.005 (Bi4Ti3O 12 )1O j .

[0074] Preparation Example 3

[0075] Weigh out 1 mol of ammonium molybdate (Mo), 0.1 mol of ammonium metatungstate (W), and 0.3 mol of ammonium niobate oxalate (Nb) and dissolve them in 3000 g of water to obtain the first solution; weigh out 0.04 mol of bismuth nitrate (Bi), 0.2 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.3 mol of nickel nitrate (Ni), 0.015 mol of cesium nitrate (Cs), 0.021 mol of cerium nitrate (Ce), and 0.007 mol of lanthanum nitrate (La) and dissolve them in 200 g of water to obtain the second solution; heat the first solution to 70 °C and add 2 mol of Bi₄Ti₃O₃. 12 (Average particle size 5 μm) were mixed and stirred evenly; then the second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80 °C until it reached a viscous state. The slurry was then dried at 100 °C for 6 hours, and finally calcined in air at 550 °C for 2 hours to obtain the catalyst MoBi. 0.04 Fe 0.2 Co 0.2 Ni 0.3 Nb 0.3 W 0.1 Cs 0.015 Ce 0.021 La 0.007 (Bi4Ti3O 12 )2O j .

[0076] Preparation Example 4

[0077] 1 mol of ammonium molybdate (Mo) and 0.5 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution; 0.01 mol of bismuth nitrate (Bi), 0.5 mol of ferric nitrate (Fe), 0.4 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.03 mol of rubidium nitrate (Rb), 0.03 mol of cerium nitrate (Ce), and 0.01 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain the second solution; the first solution was heated to 70 °C, and 1.5 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 8 μm) were mixed and stirred until homogeneous; then a second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80 °C until it reached a viscous state. The slurry was then dried at 100 °C for 6 hours, and finally calcined in air at 550 °C for 2 hours to obtain the catalyst MoBi. 0.01 Fe 0.5 Co 0.4 Ni 0.4 Nb 0.5 Rb 0.03 Ce 0.0 3La 0.01 (Bi4Ti3O 12 ) 1.5 O j .

[0078] Preparation Example 5

[0079] 1 mol of ammonium molybdate (Mo) and 0.2 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution; 0.05 mol of bismuth nitrate (Bi), 0.1 mol of ferric nitrate (Fe), 0.1 mol of cobalt nitrate (Co), 0.1 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.015 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain the second solution; the first solution was heated to 70 °C, and 1.5 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 8μm) was mixed and stirred evenly; then the second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80℃ until it reached a viscous state. The slurry was then dried at 100℃ for 6 hours, and finally calcined in air at 550℃ for 2 hours to obtain the catalyst.

[0080] MoBi 0.05 Fe 0.1 Co 0.1 Ni 0.1 Nb 0.2 Rb 0.02 Ce 0.015 La 0.005 (Bi4Ti3O 12 ) 1.5 O j .

[0081] Preparation Example 6

[0082] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution; 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), and 0.025 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain the second solution; the first solution was heated to 70 °C, and 1.5 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 8μm) was mixed and stirred evenly; then the second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80℃ until it reached a viscous state. The slurry was then dried at 100℃ for 6 hours, and finally calcined in air at 550℃ for 2 hours to obtain the catalyst.

[0083] MoBi 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 La 0.025 (Bi4Ti3O 12 ) 1.5 O j .

[0084] Preparation Example 7

[0085] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution; 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), and 0.025 mol of cerium nitrate (Ce) were dissolved in 200 g of water to obtain the second solution; the first solution was heated to 70 °C, and 1.5 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 8 μm) were mixed and stirred until homogeneous; then a second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80 °C until it reached a viscous state. The slurry was then dried at 100 °C for 6 hours, and finally calcined in air at 550 °C for 2 hours to obtain the catalyst MoBi. 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.025

[0086] (Bi4Ti3O 12 ) 1.5 O j .

[0087] Preparation Example 8

[0088] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution; 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.02 mol of cerium nitrate (Ce), and 0.01 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain the second solution; the first solution was heated to 70 °C, and 1.5 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 8μm) was mixed and stirred evenly; then the second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80℃ until it reached a viscous state. The slurry was then dried at 100℃ for 6 hours, and finally calcined in air at 550℃ for 2 hours to obtain the catalyst.

[0089] MoBi 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.02 La 0.01 (Bi4Ti3O 12 ) 1.5 O j .

[0090] Preparation Example 9

[0091] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution; 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.02 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain the second solution; the first solution was heated to 70 °C, and 1.5 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 20μm), mix and stir evenly; then add the second solution to obtain a slurry, continue stirring and concentrating the slurry at 80℃ until it becomes viscous, then dry the slurry at 100℃ for 6 hours, and finally calcine it in air at 550℃ for 2 hours to obtain the catalyst.

[0092] MoBi 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.02 La 0.005 (Bi4Ti3O 12 ) 1.5 Oj .

[0093] Preparation Example 10

[0094] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain the first solution. 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.02 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain the second solution. The first solution was heated to 70 °C, and 3 mol of Bi₄Ti₃O₃ was added. 12 (Average particle size 8μm) was mixed and stirred evenly; then the second solution was added to obtain a slurry. The slurry was stirred and concentrated at 80℃ until it reached a viscous state. The slurry was then dried at 100℃ for 6 hours, and finally calcined in air at 550℃ for 2 hours to obtain the catalyst.

[0095] MoBi 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.02 La 0.005 (Bi4Ti3O 12 )3O j .

[0096] Comparative Example 1

[0097] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain a first solution. 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.02 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain a second solution. The first solution was heated to 70 °C, and the second solution was added and mixed thoroughly. The mixture was then stirred and concentrated at 80 °C until it reached a viscous consistency. After drying at 100 °C for 6 hours, the mixture was finally calcined at 550 °C in air for 2 hours to obtain the catalyst.

[0098] MoBi 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.02 La 0.005 O j .

[0099] Comparative Example 2

[0100] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain a first solution. 6.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.02 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain a second solution. The first solution was heated to 70 °C, and 4.5 mol of TiO2 (average particle size 8 μm) was added and stirred until homogeneous. The second solution was then added to obtain a slurry. The slurry was stirred and concentrated at 80 °C until it reached a viscous state. It was then dried at 100 °C for 6 hours and finally calcined in air at 550 °C for 2 hours to obtain the catalyst.

[0101] MoBi 6.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.02 La 0.005 (TiO2) 4.5 O j .

[0102] Comparative Example 3

[0103] 1 mol of ammonium molybdate (Mo) and 0.3 mol of ammonium niobate (Nb) were dissolved in 3000 g of water to obtain a first solution. 0.03 mol of bismuth nitrate (Bi), 0.3 mol of ferric nitrate (Fe), 0.2 mol of cobalt nitrate (Co), 0.4 mol of nickel nitrate (Ni), 0.02 mol of rubidium nitrate (Rb), 0.02 mol of cerium nitrate (Ce), and 0.005 mol of lanthanum nitrate (La) were dissolved in 200 g of water to obtain a second solution. The first solution was heated to 70 °C, and 4.5 mol of TiO2 (average particle size 8 μm) was added and stirred until homogeneous. The second solution was then added to obtain a slurry. The slurry was stirred and concentrated at 80 °C until it reached a viscous state. It was then dried at 100 °C for 6 hours and finally calcined in air at 550 °C for 2 hours to obtain the catalyst.

[0104] MoBi 0.03 Fe 0.3 Co 0.2 Ni 0.4 Nb 0.3 Rb 0.02 Ce 0.02 La 0.005 (TiO2) 4.5 O j .

[0105] Catalyst testing:

[0106] The catalysts prepared in Examples 1-10 and Comparative Examples 1-3 were respectively loaded into fixed-bed reactors. Catalyst tests were conducted under the following conditions: reaction temperature of 315℃, reaction pressure of 0.01MPa, volume ratio of propylene, water vapor, and air of 1:1.5:7.7, and volume hourly space velocity of 1100mL / g·h. The test results are shown in Table 1.

[0107] Table 1

[0108]

[0109] 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 molybdenum-bismuth-iron catalyst, characterized in that, The catalyst component has the general formula MoBi. a Fe b X c Y d Z e Q f (Bi4Ti3O 12 ) g O j ; Wherein, X is at least one of alkaline earth metals and Group VIII metals; Y is at least one of Group VB metals, Group VIB metals, and Group VA metals; Z is at least one of alkali metals; and Q is at least one of rare earth elements. The values ​​of a are 0.01-0.05; b is 0.1-0.5; c is 0.2-0.8; d is 0.1-0.5; e is 0.01-0.03; f is 0.01-0.04; g is 0.5-3; and j is the total number of oxygen atoms required to satisfy the oxidation states of each element in the catalyst.

2. The catalyst according to claim 1, wherein, Bi4Ti3O 12 It exists in the form of a compound; and / or Bi4Ti3O 12 The average particle size is 1-20 μm, preferably 1-10 μm.

3. The catalyst according to claim 1 or 2, wherein, The formula MoBi a Fe b X c Y d Z e Q f (Bi4Ti3O 12 ) g O j middle, X is selected from at least one of Mg, Co, and Ni; and / or Y is selected from at least one of Nb, W, and Sb; and / or Z is selected from at least one of K, Rb, and Cs; and / or Q is selected from at least one of Ce, La, Nd, and Pr, preferably at least one of Ce, La, and Nd; more preferably Ce and La, with a molar ratio of Ce to La of 2-5, preferably 3-4; and / or The value of a is 0.02-0.04; and / or the value of b is 0.2-0.4; and / or the value of c is 0.4-0.7; and / or the value of d is 0.2-0.4; and / or the value of e is 0.01-0.02; and / or the value of f is 0.02-0.03; and / or the value of g is 1-2.

4. A method for preparing the molybdenum-bismuth-iron catalyst according to any one of claims 1-3, characterized in that, The preparation method includes: Bi4Ti3O 12 The slurry was mixed with a solution containing Mo, Bi, Fe, X, Y, Z, and Q sources, and then dried and calcined to obtain a molybdenum-bismuth-iron catalyst.

5. The preparation method according to claim 4, wherein, The preparation method includes: (1) Bi4Ti3O 12 Add to the first solution containing Mo source and Y source and mix; (2) The second solution containing Bi source, Fe source, X source, Z source and Q source is added to the mixture in step (1) to obtain a slurry, which is then dried and calcined to obtain a molybdenum-bismuth-iron catalyst.

6. The molybdenum-bismuth-iron catalyst prepared by the method according to any one of claims 4-5.

7. The application of the molybdenum-bismuth-iron catalyst according to any one of claims 1-3 and 6 in oxidation reactions, preferably in the oxidation of olefins, and more preferably the olefins are C3-C5 α-olefins.

8. A method for oxidizing olefins, characterized in that, The method includes reacting an olefin-containing feed gas with an oxidant in the presence of a molybdenum-bismuth-iron catalyst as described in any one of claims 1-3 and 6.

9. The method according to claim 8, wherein, The olefin is a C3-C5 α-olefin, preferably propylene; and / or The olefin-containing feed gas also includes a dilution gas, which is selected from inert gases and / or water vapor. and / or The oxidant is selected from one or more oxidizing gases, preferably oxygen and / or air; and / or The volume ratio of the olefin, dilution gas and oxidant is 1:0.5-5:6-8.

10. The method according to claim 8 or 9, wherein, The conditions for the contact reaction include: The temperature is 300-550℃, preferably 300-380℃; and / or The pressure is 0.01-0.08 MPa; and / or The volumetric hourly space velocity (VHSV) of the olefin-containing feed gas is 600-1200 mL / g·h.

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