Catalyst for synthesizing (methyl)acrolein, preparation therefor and use thereof

Abstract

The present application provides a catalyst. The catalyst comprises a catalytic active component, and the catalytic active component comprises a composite metal oxide represented by the following general formula: AaBibCocFedMoeNifOx, further comprises a reinforcing component and / or a lubricating component. The present application further provides a preparation method for the catalyst and a method for preparing (methyl)acrolein by catalytic oxidation of olefin using the catalyst. The catalyst developed by the present invention has good mechanical strength and porosity, has excellent catalytic activity and excellent selectivity to a target product (methyl)acrolein, and is suitable for long-term use of catalytic reaction devices.

Description

Catalyst for synthesizing (meth)acrolein and its preparation and application Technical Field

[0001] The present application relates to the field of catalysis, and more specifically to a catalyst comprising a composite metal oxide catalytically active component, a method for preparing the catalyst, and a method for synthesizing (meth)acrolein using the catalyst. Background Art

[0002] Acrolein and methacrolein, with their structural formulas of CH2=CH-CHO and CH2=C(CH3)-CHO, respectively, are very important chemical raw materials and intermediates, widely used in various synthesis processes and steps in the fields of chemicals, resins, medicines, pesticides, feed additives, water treatment agents, and the like. For example, they can be used to produce chemicals such as glutaraldehyde, 1,3-propylene glycol, acrylic acid, and picoline; can be used to produce methionine, which is used as a feed additive; and are also used in the fields of medicine, food, and cosmetics. They can be used to synthesize bactericides and water treatment agents for oilfield water treatment and environmental water treatment to inhibit bacterial growth. They can also be used as chromatographic analysis standards. Because (meth)acrolein raw materials are in great demand across all industries, people have been continuously investing a large amount of manpower and material resources to develop new catalysts and new processes for synthesizing (meth)acrolein. For example, some processes have been developed in the art for preparing a mixed product containing both (meth)acrolein and (meth)acrylic acid by selective catalytic oxidation using propylene or isobutylene (or tert-butyl alcohol) as starting materials. However, the drawbacks of these technologies are that the catalysts often require the use of expensive or toxic metal elements or components that pose a significant potential threat to environmental safety. Furthermore, the products obtained by these processes are often a mixture of (meth)acrolein and (meth)acrylic acid, and the (meth)acrylic acid concentration is always maintained at a relatively high level, making it impossible to synthesize the target product (meth)acrolein with high selectivity. The research results to date have only reported the total yield of (meth)acrylic acid and (meth)acrolein, but in reality, the selectivity and yield of (meth)acrolein are always unsatisfactory. In addition, the catalysts reported in the prior art often have the problem of insufficient mechanical strength. Under long-term operation on an industrial scale, the catalysts will rapidly wear out in the catalytic reaction equipment, resulting in the human, material, and time costs associated with equipment shutdown and catalyst replacement. The technologies reported in the prior art for improving the mechanical strength of catalysts always sacrifice catalytic activity and cannot maintain catalytic performance while improving mechanical strength, let alone achieve dual improvements in mechanical strength and catalytic performance.

[0003] To address the above-mentioned issues, those skilled in the art have invested significant resources and effort in conducting extensive research and exploration into catalyst systems, selective oxidation processes, and their specific parameters. However, the results obtained remain unsatisfactory. To date, there remains an urgent need to develop a new technology that can address the above-mentioned technical issues.

[0004] Summary of the Invention

[0005] In response to the above problems, the inventors of this application have conducted extensive and in-depth research and successfully developed a novel catalyst and a uniquely designed preparation method thereof. When used in the above-mentioned selective catalytic oxidation reaction, this catalyst can effectively solve the long-standing problems in the prior art that have been in urgent need of solution.

[0006] The first aspect of the present application provides a catalyst comprising a catalytically active component, wherein the catalytically active component comprises a composite metal oxide represented by the general formula I: A a Bi b Co c Fe d Mo e Ni f O x Formula I

[0007] wherein A represents one or more alkali metals selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium;

[0008] a is 0.01-0.25, b is 0.5-1, c is 7-13, d is 1.5-4, e is 10-14, f is 0.5-2, and the value of x makes the composite metal oxide represented by general formula I electrically neutral.

[0009] According to one embodiment of the first aspect of the present application, the catalyst further comprises a reinforcing component selected from silica, alumina, clay, kaolin, talc, pumice, aluminum silicate, magnesium silicate, silicon carbide, zeolite, molecular sieve, glass fiber, asbestos, or a combination thereof.

[0010] According to another embodiment of the first aspect of the present application, the catalyst further comprises a lubricating component selected from boron nitride, boron fluoride, graphite, graphene, quantum dots, carbon black, carbon nanotubes, or a combination thereof.

[0011] According to another embodiment of the first aspect of the present application, the catalyst does not contain copper.

[0012] The second aspect of the present application provides a method for synthesizing the catalyst of the present invention, the method comprising:

[0013] Step A: providing a mixture of raw metal elements, wherein the mixture is in the form of a solution, slurry, suspension or colloid;

[0014] Step B: drying the mixture to obtain a catalyst active phase precursor;

[0015] Step C: calcining the catalyst active phase precursor.

[0016] According to one embodiment of the second aspect of the present application, in step A, the preparation of the mixed material includes adding a reinforcing component or a precursor of a reinforcing component.

[0017] According to another embodiment of the second aspect of the present application, in the step B, the thermally lost component content of the catalyst active phase precursor is 25-40 wt%.

[0018] According to another embodiment of the second aspect of the present application, after step B and before step C, the catalyst active phase precursor is pre-calcined at a temperature of 120-300°C to obtain a pre-calcined catalyst active phase precursor, the thermal loss component content of which is controlled at 20-24 weight %.

[0019] According to another embodiment of the second aspect of the present application, the catalyst active phase precursor or the pre-fired catalyst active phase precursor is mixed with a lubricating component, an optional adhesive, and an optional auxiliary agent, and is formed into a shaped green body through a molding process, and then the shaped green body is calcined in step C.

[0020] According to another embodiment of the second aspect of the present application, the lubricating component is selected from boron nitride, boron fluoride, graphite, graphene, quantum dots, carbon black, carbon nanotubes, or a combination thereof.

[0021] According to another embodiment of the second aspect of the present application, the binder is selected from water, methanol, ethanol, propanol, butanol, ethylene glycol, ethyl ether, acetone, or a mixture thereof.

[0022] According to another embodiment of the second aspect of the present application, the auxiliary agent is selected from at least one of the following: ammonium nitrate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, starch, acetic acid, ammonium acetate, oxalic acid, ammonium oxalate, asphalt, stearic acid, malonic acid, ground polyethylene, and ground polypropylene.

[0023] According to another embodiment of the second aspect of the present application, calcination is carried out in two steps in step C; wherein the first calcination is carried out at a temperature of 150-400°C, and the catalyst active phase precursor or the pre-calcined catalyst active phase precursor has a heat loss component content of 8-12 weight% after the first calcination; the second calcination is carried out at a temperature of 450-550°C, and the catalyst is obtained after the second calcination.

[0024] The third aspect of the present application provides a method for preparing (meth)acrolein by catalytic oxidation using propylene or isobutylene as a raw material, the method comprising catalytically oxidizing olefin in the presence of the catalyst of the present invention or the catalyst prepared by the method of the present invention to prepare (meth)acrolein. DETAILED DESCRIPTION

[0025] "Range" disclosed herein is in the form of a lower limit and an upper limit. It can be one or more lower limits, and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges that can be defined in this way are inclusive and combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, a range of 60-120 and 80-110 is listed for a particular parameter, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and if the maximum range values ​​listed are 3, 4, and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0026] In this application, unless otherwise specified, the numerical range "ab" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is merely an abbreviation for these numerical combinations.

[0027] In this application, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution.

[0028] In this application, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0029] In this application, unless otherwise specified, the term "comprising" as used herein may be open-ended or closed-ended. For example, "comprising" may mean that other components not listed may also be included, or only the listed components may be included.

[0030] The catalyst of the present application comprises an active component, and may optionally further comprise one or both of a reinforcing component and a lubricating component.

[0031] A technical advancement of the present application is that the composition of the active component in the catalyst is specifically limited, so that the active component of the catalyst of the present application has a composition different from that of the catalyst of the prior art. According to one embodiment of the present application, the active component of the catalyst of the present application comprises a composite metal oxide represented by the general formula I: A aBi b Co c Fe d Mo e Ni f O x Formula I

[0032] According to one embodiment of the present application, A in the general formula I represents one or more alkali metals selected from the following: lithium, sodium, potassium, rubidium, cesium, for example, potassium. These alkali metals are present in the composite metal oxide in the form of +1 valent cations. According to one embodiment of the present application, the subscript a of A in the general formula I represents the molar ratio of the alkali metal element relative to other elements in the composite metal oxide shown in the general formula I, and the value of a can be 0.01-0.25, for example, the value of a can be 0.015-0.22, or 0.02-0.20, or 0.025-0.18, or 0.03-0.16, or 0.04-0.15, or 0.05-0.12, or 0.06-0.1, or 0.08-0.09, or can be within the numerical range obtained by combining any two of the above end values.

[0033] According to one embodiment of the present application, in the composite metal oxide shown in the general formula I, the valence state of the Bi element can be +3, +5, or a combination of the above two valence states. According to an exemplary embodiment, all Bi elements in the composite metal oxide are +3 valence. According to one embodiment of the present application, the subscript b of Bi in the general formula I represents the molar ratio of the bismuth element relative to other elements in the composite metal oxide shown in the general formula I, and the value of b can be 0.50-1, for example, the value of b can be 0.55-0.95, for example, it can be 0.60-0.90, or 0.65-0.85, or 0.70-0.80, or 0.75-0.80, or it can be within the numerical range obtained by combining any two of the above end values.

[0034] According to one embodiment of the present application, in the composite metal oxide represented by the general formula I, the valence state of the Co element can be +1, +2, +3, +4, or a combination of the above valence states. According to an exemplary embodiment, the valence state of the Co element in the composite metal oxide is +2 (CoO), +3 (Co2O3), or a combination of +2 and +3 (Co3O4). According to one embodiment of the present application, the subscript c of Co in the general formula I represents the molar ratio of the cobalt element relative to other elements in the composite metal oxide represented by the general formula I. The value of c can be 7-13, for example, the value of c can be 8-12, for example, it can be 9-11, or 9.5-10, or it can be within the numerical range obtained by combining any two of the above end values.

[0035] According to one embodiment of the present application, in the composite metal oxide represented by the general formula I, the valence state of the Fe element may be +2, +3, or a combination of the above valence states. According to an exemplary embodiment, the valence state of the Fe element in the composite metal oxide is +3 (Fe2O3), or a combination of +2 and +3 (Fe3O4). According to one embodiment of the present application, the subscript d of Fe in the general formula I represents the molar ratio of the iron element relative to other elements in the composite metal oxide represented by the general formula I, and the value of d may be 1.5-4, for example, the value of d may be 1.6-3.9, for example, it may be 1.7-3.8, or 1.8-3.7, or 1.9-3.6, or 2.0-3.5, or 2.1-3.4, or 2.2-3.3, or 2.5-3.0, or 2.6-2.9, or 2.7-2.8, or it may be within the numerical range obtained by combining any two of the above end values.

[0036] According to one embodiment of the present application, in the composite metal oxide represented by the general formula I, the valence state of the Mo element may be +1, +2, +3, +4, +5, +6, or a combination of the above valence states. According to an exemplary embodiment, the valence state of the Mo element in the composite metal oxide is +4, +6, or a combination of +4 and +6. According to one embodiment of the present application, the subscript e of Mo in the general formula I represents the molar ratio of the molybdenum element relative to other elements in the composite metal oxide represented by the general formula I. The value of e may be 10-14, for example, the value of e may be 11-13, for example, it may be 12-12.5, or it may be within the numerical range obtained by combining any two of the above end values.

[0037] According to one embodiment of the present application, in the composite metal oxide represented by the general formula I, the valence state of the Ni element may be +2, +3, or a combination of +2 and +3. According to an exemplary embodiment, the valence state of the Ni element in the composite metal oxide is +2. According to one embodiment of the present application, the subscript f of Ni in the general formula I represents the molar ratio of the nickel element relative to other elements in the composite metal oxide represented by the general formula I. The value of f may be 0.5-2, for example, the value of f may be 0.55-1.8, for example, it may be 0.60-1.6, or 0.65-1.5, or 0.7-1.2, or 0.75-1.1, or 0.80-1.0, or 0.85-0.90, or it may be within the numerical range obtained by combining any two of the above end values.

[0038] In the present application, the value of the subscript x of the oxygen element in the general formula I depends on the type, valence and molar ratio of all cations in the composite oxide, so that the composite oxide is electrically neutral as a whole.

[0039] According to one embodiment of the present application, the catalyst of the present application does not contain copper. According to another embodiment of the present application, the catalyst of the present application does not contain T1 element. According to another embodiment of the present application, the catalyst of the present application does not contain alkaline earth metal elements. According to another embodiment of the present application, the catalyst of the present application does not contain P element. According to another embodiment of the present application, the catalyst of the present application does not contain titanium element. According to another embodiment of the present application, the catalyst of the present application does not contain Zr element. According to another embodiment of the present application, the catalyst of the present application does not contain Hf element. According to another embodiment of the present application, the catalyst of the present application does not contain Zn element. According to another embodiment of the present application, the catalyst of the present application does not contain the following elements: N, P, As, Te. According to another embodiment of the present application, the catalyst of the present application does not contain the following elements: S, Se, Sb. According to another embodiment of the present application, the catalyst of the present application does not contain Y element and rare earth elements. According to another embodiment of the present application, the catalyst of the present application does not contain precious metal elements, and the precious metal elements include Au, Ag, Ru, Rh, Pd, Os, Ir, and Pt. According to another embodiment of the present application, the catalyst of the present application does not contain chromium, cadmium, and mercury. According to another embodiment of the present application, the catalyst of the present application is halogen-free. According to another embodiment of the present application, the catalyst of the present application is free of the following elements: copper, thallium, alkaline earth metals, phosphorus, titanium, zirconium, hafnium, zinc, nitrogen, phosphorus, arsenic, tellurium, sulfur, selenium, antimony, yttrium, rare earth elements, gold, silver, ruthenium, rhodium, palladium, osmium, iridium, platinum, chromium, cadmium, mercury, and halogen. According to one embodiment of the present application, the active component of the catalyst of the present application contains only the composite metal oxide described in general formula I, and does not contain other elements.

[0040] In the present invention, when it is described that the catalyst of the present invention "does not contain a certain element", it means that no such element is intentionally added during the synthesis process of the catalyst, so that the catalyst finally obtained does not contain such element at all, or substantially does not contain such element, or may contain only a very small amount or even a trace amount of such element introduced as an impurity. For example, such element may be contained as an impurity in various raw materials (such as metal salts, metal oxides, metal hydroxides, etc.), solvents, other reagents (such as acids, bases, reinforcing components, lubricating components, adhesives, additives, etc.) used to synthesize the catalyst, or may be introduced from the surrounding reaction environment, atmosphere, catalyst synthesis container and equipment. According to one embodiment of the present invention, the introduction of impurities in the catalyst can be minimized by selecting and using raw materials, solvents and other reagents of higher purity and / or using reaction equipment or containers with higher cleanliness / surface protective layer (such as tetrafluoroethylene lining) / material free of impurities, thereby achieving more effective control of the catalyst composition. According to one embodiment of the present application, when a catalyst is described as "free of a certain element", it means that the content of such element in the catalyst is less than 0.01 wt%, or less than 50 ppm, or less than 20 ppm, or less than 10 ppm, or less than 5 ppm, or less than 2 ppm, or less than 1 ppm, or less than 0.5 ppm, or less than 0.1 ppm, based on the total weight of the catalyst.

[0041] According to one embodiment of the present application, the catalyst of the present application further comprises, in addition to the above-mentioned active components, a reinforcing component, which may be selected from one or more of the following: silicon oxide, aluminum oxide, clay, kaolin, talc, pumice, aluminum silicate, magnesium silicate, silicon carbide, zeolite, molecular sieve, glass fiber, asbestos, or a combination thereof. According to one embodiment of the present application, based on the weight of the active components in the catalyst as 100 parts by weight, the content of the strengthening component can be 0.01-50 parts by weight, for example, 0.05-45 parts by weight, or 0.1-40 parts by weight, or 0.2-35 parts by weight, or 0.3-30 parts by weight, or 0.4-25 parts by weight, or 0.5-20 parts by weight, or 0.6-15 parts by weight, or 0.7-12 parts by weight, or 0.8-10 parts by weight, or 0.9-8 parts by weight, or 1-6 parts by weight, or 1.2-5 parts by weight, or 1.4-3 parts by weight, or 1.5-2 parts by weight, or 1.6-1.8 parts by weight, or within the numerical range obtained by combining any two of the above end values.

[0042] According to one embodiment of the present application, the catalyst of the present application further comprises a lubricating component in addition to the above-mentioned active components, and the lubricating component can be selected from one or more of the following: boron nitride, boron fluoride, graphite, graphene, quantum dots, carbon black, carbon nanotubes, or a combination thereof. According to one embodiment of the present application, based on the weight of the active components in the catalyst as 100 parts by weight, the content of the lubricating component can be 0.1-18 parts by weight, for example, 0.5-16 parts by weight, or 0.8-15 parts by weight, or 1-14 parts by weight, or 1.1-12 parts by weight, or 1.2-10 parts by weight, or 1.3-8 parts by weight, or 1.4-7 parts by weight, or 1.5-6 parts by weight, or 1.6-5 parts by weight, or 1.7-4 parts by weight, or 1.8-3 parts by weight, or 1.9-2.5 parts by weight, or 1.9-2.2 parts by weight, or 2.0-2.1 parts by weight, or within the numerical range obtained by combining any two of the above end values.

[0043] According to one embodiment of the present application, the catalyst of the present application comprises the aforementioned strengthening component and lubricating component.

[0044] Another inventive point of the present application is the development of a method for synthesizing the catalyst of the present application, which can further improve the catalytic performance and mechanical properties of the catalyst through specially designed steps, raw material / auxiliary agent design and process parameters.

[0045] The method of the present application comprises the following steps in sequence: Step A: providing a mixture of raw metal elements, wherein the mixture is in the form of a solution, slurry, suspension or colloid; Step B: drying the mixture to obtain a catalyst active phase precursor; Step C: calcining the catalyst active phase precursor.

[0046] According to one embodiment of the present application, in step A, solutions of soluble compounds of various metal elements in the composite metal oxide are mixed to form the mixed material. For example, the source of the alkali metal can be selected from one or more of the following alkali metal compounds: alkali metal nitrates, alkali metal hydroxides, formates, acetates, etc.; the source of the molybdenum element can be selected from one or more of the following: molybdenum phosphate, molybdenum nitrate, ammonium molybdate, etc.; the source of other metal elements in the composite metal oxide, such as bismuth, cobalt, iron and nickel, can be selected from one or more of the following salts: nitrates, formates, acetates, chlorides or ammonium salts of their metal acids. According to one embodiment of the present application, solutions of these metals can be obtained by dissolving the oxides of the above metals in acids (such as nitric acid, hydrochloric acid, phosphoric acid, aqua regia, etc.). According to another embodiment of the present application, the salts of the above metals (such as analytically pure metal salts) can be purchased directly from suppliers to prepare the solutions of the metal salts. According to one embodiment of the present application, the concentration of the metal salt aqueous solution can be 5wt% to -80wt%, or 10-70wt%, or 20-60wt%, or 30-50wt%, or 40-45wt%, or the concentration range can be within the numerical range obtained by combining any two of the above end values.

[0047] According to one embodiment of the present application, the mixing in step A is performed at a temperature of 60-70° C. According to another embodiment of the present application, the mixing process can be continued until a uniformly mixed mixture is obtained, for example, the mixing process can be continued for 1 minute to 12 hours, for example, 3 minutes to 10 hours, or 5 minutes to 8 hours, or 8 minutes to 6 hours, or 10 minutes to 5 hours, or 12 minutes to 4 hours, or 15 minutes to 3 hours, or 20 minutes to 2 hours, or 30 minutes to 1 hour, or the duration of the mixing process can be within the numerical range obtained by combining any two of the above end values.

[0048] According to another embodiment of the present application, in step A, the preparation of the mixed material further includes adding a reinforcing component or a precursor of the reinforcing component. For example, the reinforcing component can be the above-mentioned reinforcing component (such as silicon oxide, aluminum oxide, clay, kaolin, talc, pumice, aluminum silicate, magnesium silicate, silicon carbide, zeolite, molecular sieve, glass fiber, asbestos, or a combination thereof); the precursor can be a material that can form the reinforcing component after subsequent drying and calcination treatment, such as silica sol, tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate, alumina colloid, silica-alumina colloid, etc. According to one embodiment of the present application, by selecting the amount of the reinforcing component or its precursor, the weight ratio of the active component to the reinforcing component in the final catalyst is made to meet the above-defined range.

[0049] According to another embodiment of the present application, the mixture prepared in step A also contains a solvent (e.g., water), various metal elements for the composite metal oxide (e.g., in the form of salts, hydroxides, or oxides), and an optional strengthening component or a precursor of the strengthening component. Based on the total weight of the mixture, the solids content of the mixture [(total weight of all components excluding the solvent / total weight of the mixture) × 100%) can be 1-80% by weight, e.g., 5-70% by weight, or 10-60% by weight, or 20-50% by weight, or 30-40% by weight, or within a range obtained by combining any two of the foregoing values.

[0050] According to one embodiment of the present application, in step B, the mixed material obtained in step A is heated to partially remove water from the mixed material to obtain a catalyst active phase precursor. When no reinforcing component or its precursor is added in step A, the catalyst active phase precursor contains only the catalyst active component or its precursor; when a reinforcing component and / or its precursor is added in step A, the catalyst active phase precursor contains both the catalyst active component or its precursor and the reinforcing component or its precursor. In addition, other additives may be added in step A, and accordingly, the catalyst active phase precursor also contains these other additives.

[0051] In this application, "heat-loss component content" is used to define the content of substances contained in a substance that can be lost under heating conditions (such as adsorbed water, crystallization water, decomposed water, nitrates, phosphates, sulfates, and other adsorbed organic matter). In this application, in each step of the catalyst synthesis method, the process conditions of drying, pre-calcining, and roasting are selected so that the intermediate product obtained in each step has a specific "heat-loss component content". It is found that this method can further improve the catalytic performance and / or mechanical properties of the catalyst.

[0052] In this application, the "heat loss component content" of the sample is determined in the following manner: using a differential thermal-thermogravimetric analyzer, in an air atmosphere, the differential thermal scanning curve and the thermogravimetric curve of the sample are plotted in the temperature range of 150-520°C, thereby determining the sample weight loss within the temperature range, which is recorded as the "heat loss component content", the unit of which is weight percentage. The larger the value, the greater the content of substances that can be lost under heating conditions (such as adsorbed water, crystallized water, decomposed water, other adsorbed organic matter, etc.) contained in the sample.

[0053] According to one embodiment of the present application, in step B, the mixture obtained in step A is dried to partially remove moisture from the mixture, so that the "heat loss component content" of the catalyst active phase precursor is 25-40% by weight, for example, 26-38% by weight, or 28-36% by weight, or 30-35% by weight, or 32-34% by weight, or within the numerical range obtained by combining any two of the above end values.

[0054] According to another embodiment of the present application, the drying can be carried out using various different equipment or methods, such as natural drying, infrared oven drying, convection oven drying, spray drying, drum drying, tunnel kiln drying, etc. The drying process can be carried out under vacuum, air atmosphere, or inert atmosphere conditions, and can be carried out in a static atmosphere or in a flowing air flow. According to another embodiment of the present application, the temperature of the drying step can be 25-180°C, such as 30-170°C, or 40-160°C, or 50-150°C, or 60-150°C, or 70-150°C, or 80-150°C, or 90-150°C, or 100-150°C, or 110-150°C, or 120-150°C, or 130-150°C, or 140-150°C, or within the numerical range obtained by combining any two of the above end values. The duration of the drying step needs to be based on the drying method and the desired target "heat loss component content", for example, the duration of the drying step can be 10 minutes to 72 hours, for example, 20 minutes to 48 hours, or 30 minutes to 36 hours, or 40 minutes to 30 hours, or 1-26 hours, or 2-24 hours, or 4-22 hours, or 6-20 hours, or 8-20 hours, or 12-20 hours, or 14-20 hours, or 16-20 hours, or 18-20 hours, or within the numerical range obtained by combining any two of the above end values.

[0055] According to one embodiment of the present application, after step B and before step C, the catalyst active phase precursor is pre-calcined at a temperature of 120-300°C to obtain a pre-calcined catalyst active phase precursor, the heat loss component content of which is controlled to be 20-24% by weight, for example, 21-23% by weight, or 22-22.5% by weight, or within the numerical range obtained by combining any two of the above end values. According to an exemplary embodiment of the present application, the pre-calcination temperature can be 120-300°C, or 130-290°C, or 140-280°C, or 150-270°C, or 160-260°C, or 170-250°C, or 180-240°C, or 190-230°C, or 200-220°C, or within the numerical range obtained by combining any two of the above end values. According to one embodiment of the present application, the pre-calcination can be carried out in air, for example, in flowing air. According to another embodiment of the present application, the flowing air can be achieved by providing an air flow with a specific flow rate into the heating device, for example, the flow rate of the air flow can be 50-500 ml / min, or 80-480 ml / min, or 100-450 ml / min, or 120-420 ml / min, or 150-400 ml / min, or 180-380 ml / min, or 200-350 ml / min, or 220-320 ml / min, or 250-300 ml / min, or 280-300 ml / min, or can be within the numerical range obtained by combining any two of the above end values. The duration of the pre-calcining step needs to be based on the temperature, air flow rate and the desired target "heat loss component content". For example, the duration of the drying step can be 10 minutes to 72 hours, such as 20 minutes to 48 hours, or 30 minutes to 36 hours, or 40 minutes to 30 hours, or 1-26 hours, or 2-24 hours, or 4-22 hours, or 6-20 hours, or 8-20 hours, or 12-20 hours, or 14-20 hours, or 16-20 hours, or 18-20 hours, or within the numerical range obtained by combining any two of the above end values.

[0056] According to one embodiment of the present application, the catalyst active phase precursor (for the case where pre-calcination is not adopted) or the pre-calcined catalyst active phase precursor (for the case where pre-calcination is adopted) is mixed with a lubricating component, an optional adhesive, and an optional auxiliary agent, and a molded green body is formed through a molding process, and then the molded green body is calcined in step C.

[0057] According to one embodiment of the present application, the lubricating component is selected from boron nitride, boron fluoride, graphite, graphene, quantum dots, carbon black, carbon nanotubes, or a combination thereof, and the amount thereof is as described above.

[0058] According to another embodiment of the present application, the binder is selected from water, methanol, ethanol, propanol, butanol, ethylene glycol, ether, acetone, or a mixture thereof. For example, based on the total weight of the green body, the content of the binder can be 0-30 weight %, for example, 1-28 weight %, or 2-26 weight %, or 3-25 weight %, or 5-22 weight %, or 6-20 weight %, or 8-18 weight %, or 10-16 weight %, or 12-14 weight %, or within the numerical range obtained by combining any two of the above end values.

[0059] Without wishing to be limited to any specific theory, the auxiliary agent can have multiple functions, such as on the one hand the auxiliary agent can make the catalyst form a more developed pore structure after molding and roasting, and on the other hand the lateral compression strength and the abrasion resistance of the catalyst can be improved. These auxiliary agents have no adverse effects on the performance (activity, selectivity of target product) of the catalyst, will not remain in the catalyst after roasting, or even if they remain in the catalyst after roasting, the material composition and the final performance of the catalyst will not be affected. According to another embodiment of the application, the auxiliary agent is selected from at least one of the following: ammonium nitrate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, starch, acetic acid, ammonium acetate, oxalic acid, ammonium oxalate, asphalt, stearic acid, malonic acid, ground polyethylene, ground polypropylene. According to one embodiment of the present application, the auxiliary agent can be added in the form of a solid or in the form of a solution. When added in the form of a solution, the concentration of the solution can be 0.5-50% by weight, such as 1-40% by weight, or 2-30% by weight, or 3-20% by weight, or 4-18% by weight, or 5-15% by weight, or 6-12% by weight, or 8-10% by weight, or within the numerical range obtained by combining any two of the above end values. According to another embodiment of the present application, based on the total weight of the green body, the content of the auxiliary agent (in terms of solid content) can be 0-25% by weight, such as 0.5-28% by weight, or 1-26% by weight, or 1.5-25% by weight, or 2-22% by weight, or 2.5-20% by weight, or 3-18% by weight, or 4-16% by weight, or 5-14% by weight, or 6-12% by weight, or 8-10% by weight, or within the numerical range obtained by combining any two of the above end values.

[0060] According to one embodiment of the present application, the molding of the catalyst can be carried out by suitable process technology, for example, by granulation, extrusion, tableting or other extrusion molding to form pellets, flakes, annular flakes, columnar materials, hollow columnar materials, etc. According to an exemplary embodiment, a green body with a hollow cylindrical shape is manufactured by a tableting process, and the green body is then calcined to form the catalyst of the present invention. According to one embodiment of the present application, the catalyst is in the form of pellets or small particles, and the particle size of the pellets / small particles is 0.1-10 mm, such as 0.5-8 mm, or 1-7 mm, or 3-6 mm, or 4-5 mm, or within the numerical range obtained by combining any two of the above end values. According to another embodiment of the present application, the catalyst is in the form of round tablets, hollow round tablets, cylinders, or hollow cylinders. For example, according to one embodiment, the catalyst is in the form of a hollow cylinder, the outer diameter of the hollow cylinder is 0.1-10 mm, for example, 0.5-8 mm, or 1-7 mm, or 3-6 mm, or 4-5 mm, or within the numerical range obtained by combining any two of the above end values; the inner diameter is 0.01-5 mm, for example, 0.05-4 mm, or 0.08-3 mm, or 0.1-2.5 mm, or 0.5-2.2 mm, or 0.8-2 mm, or 1-2 mm, or 1.5-2 mm, or within the numerical range obtained by combining any two of the above end values; the thickness is 0.1-8 mm, for example, 0.5-6 mm, or 0.8-5 mm, or 1-4.5 mm, or 1.5-4 mm, or 2-4 mm, or 2.5-3.5 mm, or 2.8-3 mm, or within the numerical range obtained by combining any two of the above end values.

[0061] According to one embodiment of the present application, the calcination can be carried out in one go, and the temperature of the calcination carried out in one go can be 150-600°C, for example, 180-550°C, or 200-520°C, or 250-500°C, or 300-450°C, or 350-400°C, or 360-380°C, or 450-550°C, or within the numerical range obtained by combining any two of the above end values; after carrying out the one-time calcination, the heat loss component content of the final catalyst obtained is controlled to be ≤6% by weight, for example, ≤5% by weight, or ≤4% by weight, or ≤3% by weight, or ≤2% by weight, or ≤1% by weight, or ≤0.5% by weight, or ≤0.1% by weight, or ≤0.05% by weight, or ≤0.01% by weight, or close to 0% by weight, or within the numerical range obtained by combining any two of the above end values. The duration of the one-time roasting step can be 10 minutes to 72 hours, for example, 20 minutes to 48 hours, or 30 minutes to 36 hours, or 40 minutes to 30 hours, or 1-26 hours, or 2-24 hours, or 4-22 hours, or 6-20 hours, or 8-20 hours, or 12-20 hours, or 14-20 hours, or 16-20 hours, or 18-20 hours, or within the numerical range obtained by combining any two of the above end values.

[0062] According to another embodiment of the present application, the calcination can be carried out in two steps, the first calcination is carried out at a temperature of 150-400°C, and the catalyst active phase precursor or the pre-calcined catalyst active phase precursor has a heat loss component content controlled at 8-12 weight% after the first calcination; the second calcination is carried out at a temperature of 450-550°C, and the catalyst is obtained after the second calcination.

[0063] According to one embodiment of the present application, the temperature of the first calcination can be 150-400°C, for example, 180-350°C, or 200-320°C, or 250-300°C, or 270-280°C, or within the numerical range obtained by combining any two of the above end values; after the first calcination, the heat loss component content of the catalyst material obtained after the first calcination is controlled at 8-12% by weight, for example, 8.2-11.8% by weight, or 8.5-11.5% by weight, or 8.8-11.2% by weight, or 9-11% by weight, or 9.2-10.8% by weight, or 9.5-10.5% by weight, or 9.8-10.2% by weight, or 9.9-10.0% by weight, or within the numerical range obtained by combining any two of the above end values. The duration of the first calcination step can be 10 minutes to 72 hours, for example, 20 minutes to 48 hours, or 30 minutes to 36 hours, or 40 minutes to 30 hours, or 1-26 hours, or 2-24 hours, or 4-22 hours, or 6-20 hours, or 8-20 hours, or 12-20 hours, or 14-20 hours, or 16-20 hours, or 18-20 hours, or within the numerical range obtained by combining any two of the above end values.

[0064] According to one embodiment of the present application, the temperature of the second calcination can be 450-550°C, for example, 460-540°C, or 470-530°C, or 480-520°C, or 490-510°C, or 500-510°C, or within the numerical range obtained by combining any two of the above end values; after the second calcination, the heat loss component content of the final catalyst material obtained after the second calcination is controlled to be ≤6% by weight, for example ≤5% by weight, or ≤4% by weight, or ≤3% by weight, or ≤2% by weight, or ≤1% by weight, or ≤0.5% by weight, or ≤0.1% by weight, or ≤0.05% by weight, or ≤0.01% by weight, or close to 0% by weight, or within the numerical range obtained by combining any two of the above end values. The duration of the second calcination step can be 10 minutes to 72 hours, for example, 20 minutes to 48 hours, or 30 minutes to 36 hours, or 40 minutes to 30 hours, or 1-26 hours, or 2-24 hours, or 4-22 hours, or 6-20 hours, or 8-20 hours, or 12-20 hours, or 14-20 hours, or 16-20 hours, or 18-20 hours, or within the numerical range obtained by combining any two of the above end values.

[0065] The calcination can be performed in an air atmosphere, an oxygen atmosphere, a nitrogen atmosphere or a vacuum environment, for example, in a static air atmosphere or in an air flow.

[0066] According to one embodiment of the present application, the catalyst prepared by the present invention has excellent mechanical strength. For example, the lateral pressure strength and wear resistance can be used to characterize the catalyst's tolerance to extrusion and friction experienced during its catalytic reaction. According to an exemplary embodiment of the present application, the lateral pressure strength of the catalyst can be measured according to the following method. The measuring instruments used are a particle strength meter and a vernier caliper. During the test, the catalyst is first sampled. Taking the granular catalyst as an example, 50 samples are randomly selected for every 500 kilograms; the thickness of the pellet is measured with a vernier caliper and the measurement results are recorded; then the radial compressive strength of the pellet is tested using the pellet strength. Specifically, the height of the pressure head in the pellet strength meter is adjusted, the pellet is placed horizontally in the middle, the start button is pressed, and after the data stabilizes, the measurement structure is recorded; finally, the strength data measured as described above is divided by the pellet thickness to obtain the lateral pressure strength of the sample. According to one embodiment of the present application, the lateral pressure strength of the catalyst of the present invention can be 5-100 N / cm, for example 8-80 N / cm, or 10-70 N / cm, or 15-60 N / cm, or 18-50 N / cm, or 20-40 N / cm, or 25-30 N / cm, or can be within the numerical range obtained by combining any two of the above end values.

[0067] According to another embodiment of the present application, the wear resistance of the catalyst can be measured using a fragility meter. For example, the wear resistance of the catalyst can be tested in the following manner: the measuring instruments used are a fragility meter and an electronic scale, 200g of the catalyst flakes after screening are weighed, and it is confirmed that there is no residual fine powder in the drum of the fragility meter. 200g of flakes are loaded into the drum of the fragility meter, and the drum of the fragility meter is set to rotate 45 times; the fragility meter is started, and the drum automatically stops after rotating 45 times, and the fragility meter is turned off; the flakes in the drum are taken out, first sieved with a 60-mesh sieve to remove the fine particles, the weight of the flakes is weighed, and then the fragments are sieved with a 7-mesh sieve, and the weight of the flakes is weighed again; the weight of the flakes after passing through the 60-mesh sieve and the 7-mesh sieve is divided by 200, and the percentage is taken as the wear resistance of this batch of flakes. In the present invention, wear resistance = mass of the catalyst after screening / mass of the unscreened catalyst. The present invention preferably has a 7-mesh sieve wear resistance > 99%, and a 60-mesh sieve wear resistance > 99.5%.

[0068] According to one embodiment of the present application, the catalyst of the present application can be used to perform a gas-solid phase selective catalytic oxidation reaction. For example, it can be used to convert propylene or isobutylene as a raw material into the target product acrylic acid or methacrolein through selective catalytic oxidation. For example, it can be used in a process for synthesizing (meth)acrolein from propylene or isobutylene as a raw material, and the process can include or exclude tail gas recycle.

[0069] According to one embodiment of the present application, the selective catalytic oxidation reaction can be carried out in the following manner: a catalyst is loaded into a reactor, and then a reaction raw material (e.g., propylene or isobutylene) and oxygen or a gas stream containing oxygen (e.g., air, or a mixture of nitrogen and oxygen, or a mixture of water vapor and oxygen, or a mixture of oxygen, water vapor and nitrogen) are allowed to flow into the reactor under catalytic reaction conditions at a specific flow rate, contacting the catalyst to react and generate (meth)acrolein. Examples of the reactor used in the present invention may include a tubular reactor, a packed bed reactor, a microchannel reactor, and the like.

[0070] According to one embodiment of the present application, the temperature of the selective catalytic oxidation reaction can be 280-400°C, for example, 300-380°C, or 300-350°C, or 320-340°C, or within the numerical range obtained by combining any two of the above end values. According to one embodiment of the present application, the pressure (absolute pressure) of the selective catalytic oxidation reaction can be 0.1-0.5 MPa, for example, 0.15-0.45 MPa, or 0.20-0.40 MPa, or 0.25-0.35 MPa, or 0.28-0.30 MPa, or within the numerical range obtained by combining any two of the above end values.

[0071] According to one embodiment of the present application, the volume space velocity of propylene (determined under STP conditions) is 120-180 hours, calculated based on the volume of the packed bed of catalyst. -1 , for example 130-170 hours -1 , or 140-160 hours -1 , or 145-150 hours -1 , or within the numerical range obtained by combining any two of the above end values. According to one embodiment of the present application, the flow rates of the input oxygen and propylene are adjusted so that the molar ratio of oxygen to propylene in the reactor is 1-10, for example, 2-9, or 3-8, or 4-7, or 5-6, or within the numerical range obtained by combining any two of the above end values. According to another embodiment of the present application, the flow rates of the input water vapor and propylene are adjusted so that the molar ratio of water vapor to propylene in the reactor is 1-15, for example, 2-12, or 3-10, or 4-8, or 5-6, or within the numerical range obtained by combining any two of the above end values. The flow rates of the input nitrogen and propylene are adjusted so that the molar ratio of nitrogen to propylene in the reactor is 0-10, for example, 1-9, or 2-8, or 3-7, or 4-6, or 5-6, or within the numerical range obtained by combining any two of the above end values.

[0072] In the following examples, the catalytic performance of the catalyst of the present application is characterized by taking the selective oxidation of propylene to produce acrolein as an example. However, the catalytic reaction of the present application is not limited to this example. The catalyst of the present application can also be applied to the reaction of selective catalytic oxidation of other olefins to produce aldehyde target products. The scope of protection of the present application is determined by the claims of the present application.

[0073] According to one embodiment of the present application, the conversion rate and selectivity of the catalytic oxidation of propylene to produce acrolein are calculated according to the following formula:

[0074] Propylene conversion (mol%) = (moles of propylene reacted) / (moles of propylene supplied) × 100%

[0075] Acrolein selectivity (mol%) = (moles of acrolein produced by the reaction) / (moles of propylene reacted) × 100%

[0076] The present application is described below in the form of specific examples for the purpose of providing a better understanding of the present application. It should be understood that these examples are merely illustrative and non-restrictive. The reagents used in the examples are all commercially available unless otherwise specified. The methods and conditions used in the examples are conventional methods and conditions unless otherwise specified.

[0077] Example

[0078] In the following examples, different formulations and process conditions were used to prepare the catalysts of the present invention and comparative catalysts, and their catalytic performance and mechanical strength properties were characterized. However, it should be noted that the following examples are only specific examples listed in this application, and the technical features of this application are not limited thereto. Any simple changes, equivalent substitutions, or other modifications made based on this application to solve basically the same technical problems and achieve basically the same technical effects are all covered by the scope of protection of this application.

[0079] The water used in the following examples was all deionized water, and all metal salts used were of analytical grade. The heat loss component contents in the examples were all measured using a DSC4000 differential thermal-thermogravimetric analyzer in an air atmosphere within a temperature range of 150-520°C.

[0080] Example 1:

[0081] In this embodiment, 450 ml of water was added to a beaker and heated to 65° C. using a water bath, 148.3 g of ammonium molybdate and 0.82 g of potassium hydroxide were added thereto, and the mixture was stirred at 65° C. to dissolve all the solids, thereby obtaining a solution A. The temperature of the solution A was maintained at 70° C.

[0082] In another beaker, add 130 ml of water and heat it to 60°C using a water bath. Then, add 56.56 g of ferric nitrate, 152.79 g of cobalt nitrate, 20.36 g of nickel nitrate and 20.37 g of bismuth nitrate in sequence. Maintain stirring at 60°C to dissolve the solids and obtain solution B. The temperature of solution B is maintained at 70°C.

[0083] While maintaining the temperature at 70°C and stirring vigorously, the above-mentioned solution B was slowly added dropwise to the solution A. Stirring was continued after the addition to obtain a uniformly mixed slurry. The slurry was poured into a magnetic disk, placed in an oven, and dried at 150°C for 20 hours. The dried product was crushed and mixed using a pulverizer to obtain a powdered catalyst active phase precursor, the heat loss component content of which was measured to be 35% by weight. The catalyst active phase precursor powder was uniformly mixed with 2% by weight of graphite using a pulverizer (the weight of the catalyst active phase precursor powder was 100% by weight, that is, the amount of graphite added was "additional" to 100% by weight). The resulting mixture powder was pressed into cylindrical hollow particles with an outer diameter of 4 mm, an inner diameter of 2 mm, and a height of 2 mm using a small tableting machine. The pressed particles were placed in a crucible, and the crucible was placed in a kiln and calcined at 500°C for 5 hours in an air atmosphere to obtain the inventive catalyst 1. The content of heat loss components is 0 wt%. The mechanical properties are characterized and the results are summarized in Table 2.

[0084] The catalytic performance of the inventive catalyst 1 was characterized using a steel tubular reactor with an outer diameter of 25 mm, a wall thickness of 3.5 mm, an inner diameter of 14 mm, and a radial length of 100 cm. 15 ml of the catalyst prepared in the above steps was placed into the tubular reactor, and both ends of the catalyst bed were sealed with glass wool. The center of the reactor was placed in a tin bath, maintaining a constant reaction temperature of 325°C.

[0085] A mixed gas comprising 8% by volume of propylene, 65% by volume of air, 8% by volume of water vapor, and 19% by volume of nitrogen was used as the reaction raw gas. The reaction raw gas was fed into the tubular reactor from the bottom inlet, and the space velocity of propylene was always maintained at 120 h -1 During the reaction, the reactor temperature was maintained at 325°C and the pressure within the reactor was maintained at atmospheric pressure. After the reaction continued for 500 hours, the propylene conversion rate and the yield of the target product, acrolein, were characterized and calculated using gas chromatography. The results are summarized in Table 2.

[0086] Example 2:

[0087] In this embodiment, 450 ml of water was added to a beaker and heated to 65° C. using a water bath, 148.3 g of ammonium molybdate and 0.82 g of potassium hydroxide were added thereto, and the mixture was stirred at 65° C. to dissolve all the solids, thereby obtaining a solution A. The temperature of the solution A was maintained at 70° C.

[0088] In another beaker, add 130 ml of water and heat it to 60°C using a water bath. Then, add 56.56 g of ferric nitrate, 152.79 g of cobalt nitrate, 20.36 g of nickel nitrate and 20.37 g of bismuth nitrate in sequence. Maintain stirring at 60°C to dissolve the solids and obtain solution B. The temperature of solution B is maintained at 70°C.

[0089] While maintaining the temperature at 70°C and stirring vigorously, Solution B was slowly added dropwise to Solution A. Stirring was continued for 20 minutes after the addition. Then, 13.46 g of silica sol (SiO2 content 50 wt%) was added and stirred until a uniformly mixed slurry was obtained. The slurry was poured into a magnetic disk, placed in an oven, and dried at 150°C for 20 hours. The dried product was pulverized and mixed using a pulverizer to obtain a powdered catalyst active phase precursor, which had a heat loss component content of 38 wt%. The pulverizer was used to uniformly mix the catalyst active phase precursor powder with 2 wt% of graphite (based on the weight of the catalyst active phase precursor powder being 100 wt%, i.e., the amount of graphite added was "additional" to the 100 wt%). The resulting mixture powder was pressed into cylindrical hollow pellets with an outer diameter of 4 mm, an inner diameter of 2 mm, and a height of 2 mm using a small tableting machine. The pressed pellets were placed in a crucible, and the crucible was calcined in a kiln at 500°C in an air atmosphere for 5 hours to obtain Inventive Catalyst 2. The thermal loss component content was 0% by weight.

[0090] The catalytic performance and mechanical properties of the inventive catalyst 2 were characterized using the same catalytic reaction equipment and steps as described in Example 1. The results are summarized in Table 2.

[0091] Example 3:

[0092] In this Example 3, inventive catalyst 3 was prepared in the same manner as in Example 2 and its performance was characterized.

[0093] The only difference between Example 3 and Example 2 is that after the catalyst active precursor is prepared, it is placed in a tube furnace, air is introduced into the tube furnace at a flow rate of 300 ml / min, and a pre-calcination operation is performed at a temperature of 200° C. for 8 hours, so that the heat loss component content of the catalyst pre-calcined material after the pre-calcination is 18 wt%. The catalyst pre-calcined material is then uniformly mixed with 2 wt% of graphite and subsequently tableted.

[0094] Example 4:

[0095] In this Example 4, inventive catalyst 4 was prepared in the same manner as in Example 2 and its performance was characterized.

[0096] The only difference between Example 4 and Example 2 is that after the catalyst active precursor is prepared, it is placed in a tube furnace, air is introduced into the tube furnace at a flow rate of 300 ml / min, and a pre-calcination operation is performed at a temperature of 200° C. for 6 hours, so that the heat loss component content of the catalyst pre-calcined material after pre-calcination is 22 wt%. The catalyst pre-calcined material is then uniformly mixed with 2 wt% of graphite and subsequently tableted.

[0097] Example 5:

[0098] In this Example 5, inventive catalyst 5 was prepared in the same manner as in Example 2 and its performance was characterized.

[0099] The only difference between Example 5 and Example 2 is that after the catalyst active precursor is prepared, it is placed in a tube furnace, air is introduced into the tube furnace at a flow rate of 300 ml / min, and a pre-calcination operation is performed at a temperature of 200° C. for 4 hours, so that the heat loss component content of the catalyst pre-calcined material after pre-calcination is 26 wt%. The catalyst pre-calcined material is then uniformly mixed with 2 wt% of graphite and subsequently tableted.

[0100] Example 6:

[0101] In Example 6, inventive catalyst 6 was prepared in the same manner as in Example 4 and its performance was characterized.

[0102] The only difference between Example 6 and Example 4 is that in the tableting step, a granulation pot is used to mix the catalyst active phase precursor powder with 2 weight% of graphite and a 40 weight% ammonium nitrate solution, so that the amount of ammonium nitrate added is 2 weight% of the catalyst active phase precursor powder. The materials are mixed evenly, and a small tableting machine is used to tablet the obtained mixture powder into cylindrical hollow particles with an outer diameter of 4 mm, an inner diameter of 2 mm, and a height of 2 mm.

[0103] Example 7:

[0104] In this Example 7, Inventive Catalyst 7 was prepared in the same manner as in Example 4 and its performance was characterized.

[0105] The only difference between this Example 7 and Example 4 is that in the tableting step, a granulation pot is used to mix the catalyst active phase precursor powder with 2 weight% of graphite and a 40 weight% ammonium nitrate solution, so that the amount of ammonium nitrate added is 4 weight% of the catalyst active phase precursor powder. The materials are mixed evenly, and a small tableting machine is used to tablet the obtained mixture powder into cylindrical hollow particles with an outer diameter of 4 mm, an inner diameter of 2 mm, and a height of 2 mm.

[0106] Example 8:

[0107] In Example 8, inventive catalyst 8 was prepared in the same manner as in Example 4 and its performance was characterized.

[0108] The only difference between Example 8 and Example 4 is that in the tableting step, a granulation pot is used to mix the catalyst active phase precursor powder with 2 weight% of graphite and 2 weight% of terephthalic acid to uniformly mix the materials, and a small tableting machine is used to tablet the obtained mixture powder into cylindrical hollow particles with an outer diameter of 4 mm, an inner diameter of 2 mm, and a height of 2 mm.

[0109] Example 9:

[0110] In this Example 9, inventive catalyst 9 was prepared in the same manner as in Example 8 and its performance was characterized.

[0111] The only difference between Example 9 and Example 8 is that in the tableting step, a granulation pot is used to mix the catalyst active phase precursor powder with 2 weight% of graphite, 2 weight% of terephthalic acid and 2 weight% of boron nitride powder to uniformly mix the materials, and a small tableting machine is used to tablet the obtained mixture powder into cylindrical hollow particles with an outer diameter of 4 mm, an inner diameter of 2 mm and a height of 2 mm.

[0112] Example 10:

[0113] In Example 10, inventive catalyst 10 was prepared in the same manner as in Example 8 and its performance was characterized.

[0114] The only difference between Example 10 and Example 8 is that in the tableting step, a granulation pot is used to mix the boron nitride powder with a weight percentage of 1.5% to uniformly mix the materials, and a small tableting machine is used to tablet the obtained mixture powder into cylindrical hollow particles with an outer diameter of 4 mm, an inner diameter of 2 mm, and a height of 2 mm.

[0115] Example 11:

[0116] In this Example 11, inventive catalyst 11 was prepared in the same manner as in Example 8 and its performance was characterized.

[0117] The only difference between Example 11 and Example 8 is that in the tableting step, a granulation pot is used to mix the catalyst active phase precursor powder with 2 weight% of graphite, 2 weight% of terephthalic acid and 6 weight% of boron nitride powder to uniformly mix the materials, and a small tableting machine is used to tablet the obtained mixture powder into cylindrical hollow particles with an outer diameter of 4 mm, an inner diameter of 2 mm and a height of 2 mm.

[0118] Example 12:

[0119] In this Example 12, inventive catalyst 12 was prepared in the same manner as in Example 10 and its performance was characterized.

[0120] The only difference between this embodiment 12 and embodiment 10 is that the one-step calcination of embodiment 10 is changed to a two-step calcination, the first calcination is carried out at a temperature of 350°C for 8 hours, so that the heat loss component content of the material after the first calcination is controlled at 10 weight%, and then the second calcination is carried out at a temperature of 500°C for XX hours to obtain the inventive catalyst 12, whose heat loss component content is 0 weight%.

[0121] Comparative Example 1:

[0122] In this comparative example 1, comparative catalyst 1 was synthesized and prepared according to the same steps as in Example 2, and its catalytic performance and mechanical properties were characterized. The only difference was that in comparative example 1, nickel nitrate was not used when synthesizing solution B.

[0123] Comparative Example 2:

[0124] In Comparative Example 2, Comparative Catalyst 1 was synthesized and prepared according to the same procedures as Example 2, and its catalytic performance and mechanical properties were characterized. The only difference was that in Comparative Example 1, nickel nitrate was not used in the synthesis of Solution B, but 20.91 g of anhydrous copper nitrate was used instead (i.e., an equimolar amount of copper nitrate was used instead of nickel nitrate).

[0125] Table 1: Evaluation results of the examples

Claims

1. A catalyst comprising a catalytically active component, wherein the catalytically active component comprises a composite metal oxide represented by the general formula I: A a Bi b Co c Fe d Mo e Ni f O x Formula I wherein A represents one or more alkali metals selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium; a is 0.01-0.25, b is 0.5-1, c is 7-13, d is 1.5-4, e is 10-14, f is 0.5-2, and the value of x makes the composite metal oxide represented by the general formula I present electrical neutrality.

2. The catalyst according to claim 1, characterized in that The catalyst further comprises one or more of the following components: a reinforcing component selected from the group consisting of silica, alumina, clay, kaolin, talc, pumice, aluminum silicate, magnesium silicate, silicon carbide, zeolite, molecular sieves, glass fiber, asbestos, or combinations thereof; The lubricating component is selected from boron nitride, boron fluoride, graphite, graphene, quantum dots, carbon black, carbon nanotubes, or a combination thereof.

3. The catalyst according to claim 1, characterized in that The catalyst does not contain copper.

4. A method for synthesizing the catalyst according to any one of claims 1 to 3, the method comprising: Step A: providing a mixture of raw metal elements, wherein the mixture is in the form of a solution, slurry, suspension or colloid; Step B: drying the mixed material to obtain a catalyst active phase precursor; Step C: calcining the catalyst active phase precursor.

5. The method according to claim 4, characterized in that In the step A, the preparation of the mixed material includes adding a reinforcing component or a precursor of a reinforcing component.

6. The method according to claim 4, characterized in that In the step B, the thermally lost component content of the catalyst active phase precursor is 25-40% by weight.

7. The method according to claim 4, characterized in that After step B and before step C, the catalyst active phase precursor is pre-calcined at a temperature of 120-300° C. to obtain a pre-calcined catalyst active phase precursor, wherein the thermal loss component content is controlled at 20-24% by weight.

8. The method according to any one of claims 4 to 7, characterized in that The catalyst active phase precursor or the pre-calcined catalyst active phase precursor is mixed with a lubricating component, an optional binder, and an optional auxiliary agent, and is formed into a green body by molding, and then the green body is calcined in step C; The lubricating component is selected from boron nitride, boron fluoride, graphite, graphene, quantum dots, carbon black, carbon nanotubes, or a combination thereof; The binder is selected from water, methanol, ethanol, propanol, butanol, ethylene glycol, ether, acetone, or a mixture thereof; The auxiliary agent is selected from at least one of the following: ammonium nitrate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, starch, acetic acid, ammonium acetate, oxalic acid, ammonium oxalate, asphalt, stearic acid, malonic acid, ground polyethylene, ground polypropylene.

9. The method according to any one of claims 4 to 7, characterized in that: In step C, roasting is carried out in two steps; The first calcination is carried out at a temperature of 150-400° C., and the content of the heat loss component of the catalyst active phase precursor or the pre-calcined catalyst active phase precursor is controlled to be 8-12% by weight after the first calcination; The second calcination is carried out at a temperature of 450-550° C., and the catalyst is obtained after the second calcination.

10. A method for preparing (meth)acrolein by catalytic oxidation using propylene or isobutylene as a raw material, the method comprising catalytically oxidizing olefin in the presence of the catalyst according to claims 1 to 3 or the catalyst prepared by the method according to claims 4 to 9 to prepare (meth)acrolein.

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