Oxidation catalysts, methods for their preparation and use, and methods for the preparation of acrylic acid

Abstract

The application provides an oxidation catalyst, a preparation method and application thereof, and a preparation method of acrylic acid. The components of the catalyst are represented by a general formula: VMo a W b X c Y d Cu e (GeO2) f Z g O j wherein X is at least one selected from Sb, Nb, Cr and Ta, Y is at least one selected from Li, K, Na and Rb, and Z is at least one selected from Mg, Ba and Ca; a is a molar ratio of Mo to V, and a is 1-6; b is a molar ratio of W to V, and b is 0.3-1; c is a molar ratio of X to V, and c is 0.1-0.6; d is a molar ratio of Y to V, and d is 0.01-0.4; e is a molar ratio of Cu to V, and e is 0.2-3; f is a molar ratio of GeO2 to V, and f is 1-15; g is a molar ratio of Z to V, and g is 0.01-0.5; and j is a molar number of oxygen atoms required to satisfy the valence of each element in the active component. The catalyst is used in an oxidation reaction of an aldehyde to prepare an acid, such as an oxidation reaction of propyl aldehyde to prepare acrylic acid, and has the advantages of high selectivity and high yield of acrylic acid, and stable structure of the catalyst.

Description

Technical Field

[0001] This invention relates to an oxidation catalyst, its preparation method and application, and a method for preparing acrylic acid. Background Technology

[0002] Acrylic acid, as one of the important basic chemical raw materials, is mainly used in the production of butyl acrylate and ethyl acrylate comonomers for water-soluble coatings and adhesives, as well as in the production of superabsorbent resins. The selective oxidation of propylene to produce acrylic acid is the most important method. This method currently mostly employs a two-step process. In the first reactor, propylene is oxidized to acrolein and partially to acrylic acid. Then, in the second reactor, acrolein is further oxidized to acrylic acid. The second reactor typically uses transition metal composite oxides such as Mo, V, Sb, and Nb as catalysts (Catalysis Today 49 (1999) 141-153).

[0003] The acidity or basicity of a catalyst has a significant impact on the selective oxidation of propylene. Strong acidic sites are considered to be active sites for carbon chain scission and the production of byproducts (Applied Catalysis A: General 278 (2004) 45-56). However, strong basicity leads to strong adsorption of acrylic acid, resulting in deep oxidation reactions and an increase in byproducts. Therefore, catalysts need to have suitable acidity or basicity, which essentially means that the catalyst needs to have appropriate electron-donating and electron-accepting capabilities. As a result, many catalysts incorporate basic components, such as alkali metals or alkaline earth metals, to adjust the catalyst's acidity or basicity (CN130172A, CN1564709A). Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in the prior art by providing a novel oxidation catalyst. This catalyst is used in the oxidation of aldehydes to prepare acids, such as the oxidation of acrolein to prepare acrylic acid. It has the advantages of high selectivity and high yield of acrylic acid, and a stable catalyst structure.

[0005] According to a first aspect of the present invention, an oxidation catalyst is provided, the components of which are represented by the general formula: VMo a W b X c Y d Cu e (GeO2) f Z g O jWherein, X is selected from at least one of Sb, Nb, Cr and Ta; Y is selected from at least one of Li, K, Na and Rb; Z is selected from at least one of Mg, Ba and Ca; a is the molar ratio of Mo to V, with a value of 1 to 6; b is the molar ratio of W to V, with a value of 0.3 to 1; c is the molar ratio of X to V, with a value of 0.1 to 0.6; d is the molar ratio of Y to V, with a value of 0.01 to 0.4; e is the molar ratio of Cu to V, with a value of 0.2 to 3; f is the molar ratio of GeO2 to V, with a value of 1 to 15; g is the molar ratio of Z to V, with a value of 0.01 to 0.5; j is the number of moles of oxygen atoms required to satisfy the oxidation states of each element in the active component.

[0006] According to a second aspect of the present invention, a method for preparing an oxidation catalyst is provided, the method comprising: mixing a first solution containing a V compound, a Mo compound, a W compound, and an X compound with an insoluble Ge compound to form a first slurry; mixing the first slurry with a second solution containing a Y compound, a Z compound, and a Cu compound to form a second slurry; concentrating the second slurry to a viscous consistency; and drying and calcining the second slurry; wherein the amounts of each substance fed satisfy the general formula of the prepared catalyst as follows: VMo a W b X c Y d Cu e (GeO2) f Z g O j Wherein, X is selected from at least one of Sb, Nb, Cr and Ta; Y is selected from at least one of Li, K, Na and Rb; Z is selected from at least one of Mg, Ba and Ca; a is the molar ratio of Mo to V, with a value of 1 to 6; b is the molar ratio of W to V, with a value of 0.3 to 1; c is the molar ratio of X to V, with a value of 0.1 to 0.6; d is the molar ratio of Y to V, with a value of 0.01 to 0.4; e is the molar ratio of Cu to V, with a value of 0.2 to 3; f is the molar ratio of GeO2 to V, with a value of 1 to 15; g is the molar ratio of Z to V, with a value of 0.01 to 0.5; j is the number of moles of oxygen atoms required to satisfy the oxidation states of each element in the active component.

[0007] According to a third aspect of the present invention, the present invention provides an oxidation catalyst prepared by the preparation method described herein.

[0008] According to a fourth aspect of the present invention, the present invention provides a method for preparing acrylic acid, the method comprising: contacting acrolein with an oxygen-containing oxidizing gas in the presence of an oxidizing catalyst, optionally in the presence of a dilutive gaseous material, wherein the catalyst is the oxidizing catalyst described in the present invention.

[0009] The catalyst of this invention is used for the oxidation of aldehydes to acids, such as the oxidation of acrolein to acrylic acid. It exhibits advantages such as high selectivity and high yield of acrylic acid, and a stable catalyst structure. The reason for this is presumably the use of water-insoluble GeO2 as the matrix, allowing the active catalyst components to coat the GeO2 surface. This avoids GeO2 completely covering the active catalyst components while utilizing the electronic regulation capabilities of GeO2 to ensure that the active components on its surface possess suitable redox properties, thereby improving the catalyst's activity and selectivity. Simultaneously, GeO2 also provides good structural strength and stability to the catalyst as a matrix. This further enhances the catalyst's stability and activity. Detailed Implementation

[0010] 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.

[0011] In this invention, particle size refers to the average particle size, which can be the particle size D32 measured by a laser particle size analyzer. The GeO2 is commercially available.

[0012] This invention provides an oxidation catalyst, the components of which are represented by the general formula: VMo a W b X c Y d Cu e (GeO2) f Z g O j In this catalyst composition, X is selected from at least one of Sb, Nb, Cr, and Ta; Y is selected from at least one of Li, K, Na, and Rb; and Z is selected from at least one of Mg, Ba, and Ca. a is the molar ratio of Mo to V, with a value of 1–6; b is the molar ratio of W to V, with a value of 0.3–1; c is the molar ratio of X to V, with a value of 0.1–0.6; d is the molar ratio of Y to V, with a value of 0.01–0.4; e is the molar ratio of Cu to V, with a value of 0.2–3; f is the molar ratio of GeO2 to V, with a value of 1–15; g is the molar ratio of Z to V, with a value of 0.01–0.5; and j is the number of moles of oxygen atoms required to satisfy the oxidation states of each element in the active component. This catalyst composition is used for the oxidation of aldehydes to acids, such as the oxidation of acrolein to acrylic acid, and has the advantages of high selectivity and high yield of acrylic acid, as well as a stable catalyst structure.

[0013] According to a preferred embodiment of the present invention, the GeO2 is a non-water-soluble oxide.

[0014] According to a preferred embodiment of the present invention, the average particle size of the GeO2 is less than 10 micrometers, and preferably, the average particle size of the GeO2 is less than 5 micrometers.

[0015] According to a preferred embodiment of the present invention, the value of a is 2 to 4; the value of b is 0.4 to 0.7; the value of c is 0.2 to 0.5; the value of d is 0.05 to 0.2; the value of e is 0.5 to 2; the value of f is 5 to 10; and the value of g is 0.1 to 0.3. This further improves the activity and stability of the oxidation catalyst.

[0016] Catalysts with the aforementioned composition can achieve the objectives of this invention, and there are no special requirements for their preparation methods. According to a preferred embodiment of this invention, a method for preparing an oxidation catalyst is provided. This method includes: mixing a first solution containing compounds V, Mo, W, and X with an insoluble Ge compound to form a first slurry; mixing the first slurry with a second solution containing compounds Y, Z, and Cu to form a second slurry; concentrating the second slurry to a viscous consistency; and drying and calcining the second slurry. The amounts of each substance fed satisfy the requirement that the general formula of the prepared catalyst is expressed as: VMo a W b X c Y d Cu e (GeO2) f Z g O j Wherein, X is selected from at least one of Sb, Nb, Cr and Ta; Y is selected from at least one of Li, K, Na and Rb; Z is selected from at least one of Mg, Ba and Ca; a is the molar ratio of Mo to V, with a value of 1 to 6; b is the molar ratio of W to V, with a value of 0.3 to 1; c is the molar ratio of X to V, with a value of 0.1 to 0.6; d is the molar ratio of Y to V, with a value of 0.01 to 0.4; e is the molar ratio of Cu to V, with a value of 0.2 to 3; f is the molar ratio of GeO2 to V, with a value of 1 to 15; g is the molar ratio of Z to V, with a value of 0.01 to 0.5; j is the number of moles of oxygen atoms required to satisfy the oxidation states of each element in the active component.

[0017] According to a preferred embodiment of the present invention, the temperature for concentration to a viscous consistency is 90-110°C.

[0018] According to a preferred embodiment of the present invention, the drying conditions include a temperature of 70 to 160°C. For example, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, and any value between them.

[0019] According to a preferred embodiment of the present invention, the drying conditions include a time of 2 to 24 hours. For example, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, and any value between them.

[0020] According to a preferred embodiment of the present invention, the calcination conditions include a temperature of 350–600°C. For example, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, and any value between them.

[0021] According to a preferred embodiment of the present invention, the calcination conditions include a time of 1 to 4 hours, such as 1 hour, 2 hours, 3 hours, 4 hours, and any value between them.

[0022] According to a preferred embodiment of the present invention, the calcination atmosphere is an inert atmosphere and / or an atmosphere containing O2. However, from an economic point of view, the calcination atmosphere is preferably air. Unless otherwise specified, the calcination atmosphere in the present invention is always air.

[0023] According to a preferred embodiment of the present invention, the insoluble Ge compound is a commonly used compound, and for the purposes of the present invention, GeO2 is preferred.

[0024] According to a preferred embodiment of the present invention, the average particle size of the GeO2 is preferably less than 10 micrometers, and more preferably, the average particle size of the GeO2 is less than 5 micrometers.

[0025] According to a preferred embodiment of the present invention, the value of a is 2 to 4; the value of b is 0.4 to 0.7; the value of c is 0.2 to 0.5; the value of d is 0.05 to 0.2; the value of e is 0.5 to 2; the value of f is 5 to 10; and the value of g is 0.1 to 0.3.

[0026] According to an embodiment of the present invention, the first and second solutions are solutions, suspensions, or mixtures of solutions and suspensions.

[0027] According to some embodiments of the preparation method of the present invention, the amount of water used in the first solution and the second solution has a wide range of selection, with the aim of fully dissolving the compound.

[0028] According to the present invention, the V compound, Mo compound, W compound, X compound, Y compound, Z compound, and Cu compound can be selected from nitrates, ammonium salts, sulfates, oxides, hydroxides, chlorides, acetates, etc.

[0029] According to a preferred embodiment of the present invention, the molar concentration of V in the first solution is 0.1-5 mol / L.

[0030] According to a preferred embodiment of the present invention, the molar concentration of Cu in the second solution is 1-10 mol / L.

[0031] According to a preferred embodiment of the present invention, the V compound may be selected from, but is not limited to, ammonium metavanadate, etc.

[0032] According to a preferred embodiment of the present invention, the Mo compound may be selected from, but is not limited to, one or more of: ammonium molybdate, molybdenum trioxide, molybdenum nitrate, molybdic acid, and sodium molybdate.

[0033] According to a preferred embodiment of the present invention, the W compound may be selected from, but is not limited to, one or more of: ammonium tungstate, tungsten trioxide, tungstic acid, sodium tungstate, and ammonium metatungstate.

[0034] According to a preferred embodiment of the present invention, the X compound may be selected from, but is not limited to, one or more of the following: niobium oxalate, niobium pentoxide, niobium pentachloride, niobic acid, niobyl nitrate, antimony nitrate, chromium nitrate, tantalum oxide, tantalum oxalate, and tantalum citrate.

[0035] According to a preferred embodiment of the present invention, the Y compound may be selected from, but is not limited to, one or more of lithium nitrate, potassium nitrate, sodium nitrate, sodium sulfate, sodium chloride, sodium acetate, sodium hydroxide, and rubidium nitrate.

[0036] According to a preferred embodiment of the present invention, the Z compound may be selected from, but is not limited to, one or more of: magnesium nitrate, calcium nitrate, magnesium sulfate, magnesium chloride, magnesium acetate, magnesium hydroxide, and barium nitrate.

[0037] According to a preferred embodiment of the present invention, the Cu compound may be selected from, but is not limited to, copper nitrate, etc.

[0038] This invention provides an oxidation catalyst prepared by the method described herein. The catalyst of this invention is used in the oxidation of aldehydes to acids, such as the oxidation of acrolein to acrylic acid, exhibiting advantages such as high selectivity and high yield of acrylic acid, and stable catalyst structure. The reason for this is presumably the use of water-insoluble GeO2 as the matrix, allowing the active catalyst components to coat the GeO2 surface. This avoids GeO2 completely covering the active catalyst components while utilizing the electronic regulation capabilities of GeO2 to ensure that the active components on its surface possess suitable redox properties, thereby improving the catalyst's activity and selectivity. Simultaneously, GeO2 also provides good structural strength and stability to the catalyst as a matrix. This enhances the catalyst's stability and activity.

[0039] This invention provides the application of the catalyst described herein in the preparation of acids from aldehydes, wherein the aldehyde is preferably a C3-C4 aldehyde, more preferably a C3-C4 enaldehyde, and more preferably acrolein.

[0040] This invention provides a method for preparing acrylic acid, the method comprising: reacting acrolein with an oxygen-containing oxidizing gas in the presence of an oxidizing catalyst, optionally in the presence of a dilutive gaseous material, wherein the catalyst is the oxidizing catalyst described in this invention.

[0041] According to a preferred embodiment of the present invention, the oxidizing gas may be pure oxygen or oxygen-enriched gas, and the oxygen-containing oxidizing gas is oxygen and / or air, preferably air. However, air is preferred from an economic perspective.

[0042] According to a preferred embodiment of the present invention, the volume ratio of acrolein to air is 1:(1-6).

[0043] According to a preferred embodiment of the present invention, in order to make the reaction more stable and controllable, it is preferable to carry out the reaction in the presence of a diluting gaseous material, preferably water vapor.

[0044] According to a preferred embodiment of the present invention, the reaction temperature can be 200–400°C.

[0045] According to a preferred embodiment of the present invention, the reaction pressure can be 0.01 to 0.08 MPa (gauge pressure).

[0046] According to a preferred embodiment of the present invention, in the raw material gas composed of acrolein, air and water vapor, the volume ratio of acrolein:air:water vapor is 1:(1.5-5):(0.5-3).

[0047] According to a preferred embodiment of the present invention, the volumetric hourly space velocity of the feed gas is 1000–1800 h⁻¹. -1 .

[0048] According to the present invention, the preferred conditions for the contact reaction include: a temperature of 200–400°C, a pressure of 0.01–0.08 MPa (gauge pressure), and a volume hourly space velocity (VHSV) of 1000–1800 h⁻¹ for the feed gas. -1 In a volume ratio, acrolein:air = 1:(1-6), preferably, in a volume ratio, acrolein:air:optionally water vapor = 1:(1.5-5):(0.5-3).

[0049] The method for preparing acrylic acid of the present invention has a high acrylic acid yield.

[0050] This invention provides a catalyst for the oxidation of acrolein to prepare acrylic acid, the catalyst having the general formula: VMo a W b X c Y d Cu e (GeO2) f Z g O j Where X is selected from at least one of Sb, Nb, Cr and Ta; Y is selected from at least one of Li, K, Na and Rb; Z is selected from at least one of Mg, Ba and Ca; a is the molar ratio of Mo to V, with a value of 1.0 to 6.0; b is the molar ratio of W to V, with a value of 0.3 to 1; c is the molar ratio of X to V, with a value of 0.1 to 0.6; d is the molar ratio of Y to V, with a value of 0.01 to 0.4; e is the molar ratio of Cu to V, with a value of 0.2 to 3; f is the molar ratio of GeO2 to V, with a value of 1 to 15; g is the molar ratio of Z to V, with a value of 0.01 to 0.5; j is the number of moles of oxygen atoms required to satisfy the valence of each element in the active component.

[0051] According to the catalyst of the present invention, preferably, a is 2.0 to 4.0; b is 0.4 to 0.7; c is 0.2 to 0.5; d is 0.05 to 0.2; e is 0.5 to 2; f is 5 to 10; and g is 0.1 to 0.3.

[0052] According to the catalyst of the present invention, the GeO2 is preferably a non-water-soluble oxide, and the average particle size of the GeO2 is less than 10 micrometers, preferably less than 5 micrometers.

[0053] This invention provides a method for preparing a catalyst for the oxidation of acrolein to acrylic acid, comprising dissolving a compound containing V, Mo, W, and X in water to obtain solution 1, and dissolving a compound containing Y, Z, and Cu in water to obtain solution 2. GeO2 is added to solution 1 and mixed thoroughly. Solution 2 is then added, and the resulting slurry is concentrated to a viscous consistency at 90-110°C, followed by drying and calcination.

[0054] According to a preferred embodiment of the present invention, the amount of each substance fed satisfies the general formula of the prepared catalyst as follows: VMo a W b X c Y d Cu e (GeO2) f O g Where X is selected from at least one of Sb, Nb, Cr, and Ta; Y is selected from at least one of Li, K, Na, and Rb; Z is selected from at least one of Mg, Ba, and Ca; a is the molar ratio of Mo to V, with a value ranging from 1.0 to 6.0; b is the molar ratio of W to V, with a value ranging from 0.3 to 1; c is the molar ratio of X to V, with a value ranging from 0.1 to 0.6; d is the molar ratio of Y to V, with a value ranging from 0.01 to 0.4; e is the molar ratio of Cu to V, with e ranging from 0.01 to 0.4. The value is 0.2-3; f is the molar ratio of GeO2 to V, and the value of f is 1-15; g is the molar ratio of Z to V, and the value of g is 0.01-0.5; j is the number of moles of oxygen atoms required to satisfy the oxidation state of each element in the active component; preferably, the value of a is 2.0-4.0; the value of b is 0.4-0.7; the value of c is 0.2-0.5; the value of d is 0.05-0.2; the value of e is 0.5-2; the value of f is 5-10; and the value of g is 0.1-0.3.

[0055] According to some specific embodiments of the preparation method of the present invention, the catalyst preparation method includes dissolving a compound containing V, a compound containing Mo, a compound containing W, and a compound containing X in water to obtain solution 1, and dissolving a compound containing Y, a compound containing Z, and a compound containing Cu in water to obtain solution 2. GeO2 is added to solution 1 and mixed thoroughly. Solution 2 is then added, and the resulting slurry is concentrated to a viscous consistency at 90-110°C, followed by drying and calcination.

[0056] This invention provides a catalyst for the oxidation of propylene to acrolein, prepared by the above method.

[0057] The general formula for the components of this catalyst is: VMo a W b X c Y d Cu e (GeO2) fZ g O j Where X is selected from at least one of Sb, Nb, Cr and Ta; Y is selected from at least one of Li, K, Na and Rb; Z is selected from at least one of Mg, Ba and Ca; a is the molar ratio of Mo to V, with a value of 1.0 to 6.0; b is the molar ratio of W to V, with a value of 0.3 to 1; c is the molar ratio of X to V, with a value of 0.1 to 0.6; d is the molar ratio of Y to V, with a value of 0.01 to 0.4; e is the molar ratio of Cu to V, with a value of 0.2 to 3; f is the molar ratio of GeO2 to V, with a value of 1 to 15; g is the molar ratio of Z to V, with a value of 0.01 to 0.5; j is the number of moles of oxygen atoms required to satisfy the valence of each element in the active component.

[0058] According to the embodiments of the catalyst described in this invention, the value of a is 2.0 to 4.0; the value of b is 0.4 to 0.7; the value of c is 0.2 to 0.5; the value of d is 0.05 to 0.2; the value of e is 0.5 to 2; the value of f is 5 to 10; and the value of g is 0.1 to 0.3.

[0059] According to some embodiments of the catalyst of the present invention, the average particle size of the GeO2 is less than 10 micrometers, preferably less than 5 micrometers.

[0060] In this invention, particle size refers to the average particle size, which can be the particle size D32 measured by a laser particle size analyzer. The GeO2 is commercially available.

[0061] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present invention.

[0062] In the embodiments and comparative examples of the present invention:

[0063] (1) The catalyst evaluation conditions are as follows:

[0064] Reactor: Fixed-bed reactor, inner diameter 25 mm, reactor length 600 mm

[0065] Catalyst: 200 grams

[0066] Reaction temperature: 260℃

[0067] Reaction pressure: 0.03 MPa (gauge pressure)

[0068] Acrolein: Air: Water vapor (raw material volume ratio) = 1:3:2

[0069] Total volumetric space velocity of raw materials: 1400 h -1

[0070] The reaction products were analyzed by gas chromatography (Agilent 7890A).

[0071] The conversion rate of acrolein and the yield of acrylic acid are defined as follows:

[0072] Acrolein conversion rate = (molar amount of acrolein reacted / total molar amount of acrolein added) × 100%;

[0073] Acrylic acid yield = (molar amount of acrylic acid produced / total molar amount of acrolein added) × 100%.

[0074] Example 1

[0075] Solution 1 is prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.4 mol Mo), ammonium metatungstate (containing 0.04 mol W), and niobium oxalate (containing 0.05 mol Nb) in 150 g of hot water. Solution 2 is prepared by dissolving sodium nitrate (containing 0.02 mol Na), calcium nitrate (containing 0.02 mol Ca), and copper nitrate (containing 0.05 mol Cu) in 50 g of water. Solution 2 is prepared by adding 0.5 mol GeO2 (average particle size 1 μm) to solution 1, mixing thoroughly, adding solution 2, heating to 100 °C, evaporating and concentrating to a viscous consistency, drying at 120 °C for 20 hours, shaping, and then calcining at 450 °C for 2 hours to obtain the product with the composition VMo4W. 0.4 Nb 0.5 Na 0.2 Cu 0.5 (GeO2)5Ca 0.2 O g The catalyst was evaluated, and the composition and results are shown in Table 1.

[0076] Example 2

[0077] Solution 1 was prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.2 mol Mo), ammonium metatungstate (containing 0.07 mol W), and chromium trioxide (containing 0.02 mol Cr) in 150 g of hot water. Solution 2 was prepared by dissolving lithium nitrate (containing 0.01 mol Li), barium nitrate (containing 0.03 mol Ba), and copper nitrate (containing 0.2 mol Cu) in 50 g of water. 1.0 mol of GeO₂ (average particle size 1 μm) was added to solution 1 and mixed thoroughly. Solution 2 was then added, and the mixture was heated to 100 °C to evaporate and concentrate to a viscous consistency. After drying at 120 °C for 20 hours, the mixture was shaped and then calcined at 450 °C for 2 hours to obtain a product with the composition VMo₂W. 0.7 Cr 0.2 Li 0.1 Cu2(GeO2) 10 Ba 0.3 O gThe catalyst was evaluated, and the composition and results are shown in Table 1.

[0078] Example 3

[0079] Solution 1 is prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.3 mol Mo), ammonium metatungstate (containing 0.05 mol W), and antimony tartrate (containing 0.04 mol Sb) in 150 g of hot water. Solution 2 is prepared by dissolving potassium nitrate (containing 0.005 mol K), magnesium nitrate (containing 0.01 mol Mg), and copper nitrate (containing 0.1 mol Cu) in 50 g of water. Solution 2 is prepared by adding 0.7 mol GeO2 (average particle size 1 μm) to solution 1, mixing thoroughly, adding solution 2, heating to 100 °C, evaporating and concentrating to a viscous consistency, drying at 120 °C for 20 hours, shaping, and then calcining at 450 °C for 2 hours to obtain the product with the composition VMo3W. 0.5 Sb 0.4 K 0.05 Cu1(GeO2)7Mg 0.1 O g The catalyst was evaluated, and the composition and results are shown in Table 1.

[0080] Example 4

[0081] Solution 1 is prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.6 mol Mo), ammonium metatungstate (containing 0.03 mol W), and niobium oxalate (containing 0.01 mol Nb) in 150 g of hot water. Solution 2 is prepared by dissolving sodium nitrate (containing 0.02 mol Na), calcium nitrate (containing 0.02 mol Ca), and copper nitrate (containing 0.05 mol Cu) in 50 g of water. Solution 2 is prepared by adding 1.5 mol GeO2 (average particle size 1 μm) to solution 1, mixing thoroughly, adding solution 2, heating to 100 °C, evaporating and concentrating to a viscous consistency, drying at 120 °C for 20 hours, shaping, and then calcining at 450 °C for 2 hours to obtain the product with the composition VMo6W. 0.3 Nb 0.1 Na 0.2 Cu 0.5 (GeO2) 15 Ca 0.2 O g The catalyst was evaluated, and the composition and results are shown in Table 1.

[0082] Example 5

[0083] Solution 1 is prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.4 mol Mo), ammonium metatungstate (containing 0.04 mol W), and niobium oxalate (containing 0.05 mol Nb) in 150 g of hot water. Solution 2 is prepared by dissolving sodium nitrate (containing 0.02 mol Na), calcium nitrate (containing 0.02 mol Ca), and copper nitrate (containing 0.05 mol Cu) in 50 g of water. Solution 2 is prepared by adding 0.1 mol GeO2 (average particle size 1 μm) to solution 1 and mixing thoroughly. Solution 2 is then added, and the mixture is heated to 100 °C to evaporate and concentrate to a viscous consistency. After drying at 120 °C for 20 hours, the mixture is shaped and then calcined at 450 °C for 2 hours to obtain a product with the composition VMo4W. 0.4 Nb 0.5 Na 0.2 Cu 0.5 (GeO2)1Ca 0.2 O g The catalyst was evaluated, and the composition and results are shown in Table 1.

[0084] Example 6

[0085] Solution 1 is prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.4 mol Mo), ammonium metatungstate (containing 0.04 mol W), and niobium oxalate (containing 0.05 mol Nb) in 150 g of hot water. Solution 2 is prepared by dissolving sodium nitrate (containing 0.02 mol Na), calcium nitrate (containing 0.02 mol Ca), and copper nitrate (containing 0.05 mol Cu) in 50 g of water. Solution 2 is prepared by adding 0.5 mol GeO2 (average particle size 8 μm) to solution 1, mixing thoroughly, adding solution 2, heating to 100 °C, evaporating and concentrating to a viscous consistency, drying at 120 °C for 20 hours, shaping, and then calcining at 450 °C for 2 hours to obtain the product with the composition VMo4W. 0.4 Nb 0.5 Na 0.2 Cu 0.5 (GeO2)5Ca 0.2 O g The catalyst was evaluated, and the composition and results are shown in Table 1.

[0086] Example 7

[0087] Ammonium metavanadate containing 0.1 mol V, ammonium molybdate containing 0.4 mol Mo, ammonium metatungstate containing 0.04 mol W, niobium oxalate containing 0.05 mol Nb, sodium nitrate containing 0.02 mol Na, calcium nitrate containing 0.02 mol Ca, and copper nitrate containing 0.05 mol Cu were dissolved in 200 g of hot water. Then, 0.5 mol GeO2 (average particle size 1 μm) was added, and the mixture was stirred evenly. The mixture was heated to 100 °C to evaporate and concentrate to a viscous consistency. After drying at 120 °C for 20 hours, the mixture was shaped and then calcined at 450 °C for 2 hours to obtain the product with the composition VMo4W. 0.4 Nb0.5 Na 0.2 Cu 0.5 (GeO2)5Ca 0.2 O g The catalyst was evaluated, and the composition and results are shown in Table 1.

[0088] Comparative Example 1

[0089] Solution 1 is prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.4 mol Mo), ammonium metatungstate (containing 0.04 mol W), and niobium oxalate (containing 0.05 mol Nb) in 150 g of hot water. Solution 2 is prepared by dissolving sodium nitrate (containing 0.02 mol Na), calcium nitrate (containing 0.02 mol Ca), and copper nitrate (containing 0.05 mol Cu) in 50 g of water. Solution 2 is added to solution 1, mixed thoroughly, heated to 100 °C, evaporated and concentrated to a viscous consistency, dried at 120 °C for 20 hours, shaped, and then calcined at 450 °C for 2 hours to obtain a solution with the composition VMo4W. 0.4 Nb 0.5 Na 0.2 Cu 0.5 Ca 0.2 O g The catalyst was evaluated, and the composition and results are shown in Table 1.

[0090] Comparative Example 2

[0091] Solution 1 is prepared by dissolving ammonium metavanadate (containing 0.1 mol V), ammonium molybdate (containing 0.4 mol Mo), ammonium metatungstate (containing 0.04 mol W), and niobium oxalate (containing 0.05 mol Nb) in 150 g of hot water. Solution 2 is prepared by dissolving sodium nitrate (containing 0.02 mol Na), calcium nitrate (containing 0.02 mol Ca), and copper nitrate (containing 0.05 mol Cu) in 50 g of water. Solution 2 is prepared by adding 0.5 mol SiO2 (average particle size 1 μm) to solution 1, mixing thoroughly, adding solution 2, heating to 100 °C, evaporating and concentrating to a viscous consistency, drying at 120 °C for 20 hours, shaping, and then calcining at 450 °C for 2 hours to obtain a solution with the composition VMo4W. 0.4 Nb 0.5 Na 0.2 Cu 0.5 (SiO2)5Ca 0.2 O g Catalyst.

[0092] Table 1

[0093]

[0094] 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. An oxidation catalyst, characterized in that, The general formula for the components of this catalyst is: VMo a W b X c Y d Cu e (GeO2) f Z g O j Wherein, X is selected from at least one of Sb, Nb, Cr and Ta; Y is selected from at least one of Li, K, Na and Rb; Z is selected from at least one of Mg, Ba and Ca; a is the molar ratio of Mo to V, with a value of 2-4; b is the molar ratio of W to V, with a value of 0.4-0.7; c is the molar ratio of X to V, with a value of 0.2-0.5; d is the molar ratio of Y to V, with a value of 0.05-0.2; e is the molar ratio of Cu to V, with a value of 0.5-2; f is the molar ratio of GeO2 to V, with a value of 5-10; g is the molar ratio of Z to V, with a value of 0.1-0.3; j is the number of moles of oxygen atoms required to satisfy the valence of each element in the active component. The GeO2 is a non-water-soluble oxide with an average particle size of less than 5 micrometers.

2. A method for preparing an oxidation catalyst, characterized in that, The method includes: mixing a first solution containing a V compound, a Mo compound, a W compound, and an X compound with an insoluble Ge compound to form a first slurry; mixing the first slurry with a second solution containing a Y compound, a Z compound, and a Cu compound to form a second slurry; concentrating the second slurry to a viscous consistency; and drying and calcining it. The feed amounts of each substance satisfy the general formula of the catalyst composition to be prepared: VMo a W b X c Y d Cu e (GeO2) f Z g O j Wherein, X is selected from at least one of Sb, Nb, Cr and Ta; Y is selected from at least one of Li, K, Na and Rb; Z is selected from at least one of Mg, Ba and Ca; a is the molar ratio of Mo to V, with a value of 2-4; b is the molar ratio of W to V, with a value of 0.4-0.7; c is the molar ratio of X to V, with a value of 0.2-0.5; d is the molar ratio of Y to V, with a value of 0.05-0.2; e is the molar ratio of Cu to V, with a value of 0.5-2; f is the molar ratio of GeO2 to V, with a value of 5-10; g is the molar ratio of Z to V, with a value of 0.1-0.3; j is the number of moles of oxygen atoms required to satisfy the valence of each element in the active component. The insoluble Ge compound is GeO2, and the average particle size of GeO2 is less than 5 micrometers.

3. The preparation method according to claim 2, wherein, In the first solution, the molar concentration of V is 0.1-5 mol / L; and / or In the second solution, the molar concentration of Cu is 1-10 mol / L; and / or The temperature for concentrating to a viscous consistency is 90-110℃; and / or The drying conditions include: a temperature of 70~160℃; and / or a time of 2-24h; and / or The calcination conditions include: a temperature of 350~600℃; and / or a time of 1~4h.

4. The oxidation catalyst prepared by the preparation method according to claim 2 or 3.

5. The application of the catalyst according to claim 1 or 4 in the preparation of acids by aldehyde oxidation.

6. The application according to claim 5, wherein, The aldehyde is a C3-C4 aldehyde.

7. The application according to claim 5, wherein, The aldehyde is a C3-C4 enaldehyde.

8. The application according to claim 5, wherein, The aldehyde is acrolein.

9. A method for preparing acrylic acid, the method comprising: In the presence of an oxidation catalyst, acrolein may optionally be reacted with an oxygen-containing oxidizing gas in the presence of a dilutive gaseous material, wherein the catalyst is the oxidation catalyst according to claim 1 or 4.

10. The method according to claim 9, wherein, The contact reaction is carried out in the presence of a diluting gaseous material; and / or The oxygen-containing oxidizing gas is oxygen and / or air; and / or The conditions for the contact reaction include: a temperature of 200~400℃, a pressure of 0.01~0.08 MPaG, and a volume hourly space velocity (VHSV) of 1000~1800 h⁻¹. -1 By volume, acrolein:air = 1:(1~6).

11. The method according to claim 10, wherein, The diluting gaseous material is water vapor; and / or The oxygen-containing oxidizing gas is air; and / or The conditions for the contact reaction include: acrolein: air: optionally water vapor = 1:(1.5~5):(0.5~3) by volume.

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