Catalyst for catalytic synthesis of unsaturated nitriles from unsaturated olefins and its preparation and application

Abstract

The invention discloses a catalyst for catalytically synthesizing unsaturated nitriles from unsaturated olefins. The catalyst comprises a silicon-containing carrier and an active component. The active component comprises an oxide and / or a cationic salt of metal A, an oxide and / or a cationic salt of element B, an oxide and / or a cationic salt of a rare earth element C, one or more of an oxide, a cationic salt and an oxyacid salt of a high-valent metal D, an oxide and / or a cationic salt of Fe and Bi, and an oxide and / or an oxyacid salt of Mo.

Description

Technical Field

[0001] The invention relates to a catalyst for catalytic synthesis of unsaturated nitrile from unsaturated olefins, and the preparation and application of the catalyst. Background Art

[0002] Unsaturated nitriles, represented by acrylonitrile, are important chemical raw materials and are currently widely produced using the fluidized bed ammoxidation process. Catalysts, one of the core technologies of this process, are subject to ongoing research and improvement. Currently, Mo-Bi-based catalysts, as relatively mature ammoxidation catalysts, have been widely used in industry. For example, CN103769138A discloses a propylene ammoxidation catalyst that exhibits good acrylonitrile selectivity and a relatively stable acrylonitrile per-pass yield at temperatures around 430°C.

[0003] Improve the load (WWH) of catalyst, i.e. the tonnage of propylene that can be processed per hour per ton of catalyst, under identical production capacity, can reduce the catalyst loading in the reactor, for reducing the design size of large-scale plant and existing device is carried out to expand capacity all have great significance, is the important trend of current acrylonitrile catalyst development.Yet, along with the lifting of catalyst load, the feed amount of reactor increases, and operating linear velocity also can lift accordingly, and faster operating linear velocity can cause catalyst wear aggravation, therefore has proposed higher requirement to the wear resistance of catalyst.Simultaneously because propylene ammoxidation is a strong exothermic reaction, higher load also can increase the reaction heat release of unit space, because reaction releases huge heat need be conducted to outside the reactor, therefore, also have very high requirement to the heat conduction efficiency of carrier.Existing catalyst can not adapt to the requirement under high load condition fully because wear resistance and heat conduction efficiency can not adapt to the requirement under high load condition fully, uses very easily to produce acrylonitrile yield and reduces quickly under high load condition, the problem of poor stability, therefore still needs further improvement.

[0004] CN1600423 and CN1600422 disclose that during the catalyst preparation process, 2-25% of solid silicon dioxide with a particle size of 5-100 nanometers is added to the carrier starting material silica sol to improve the catalyst performance, and the catalyst attrition rate is about 1.8-2.8%.

[0005] CN107282063B, CN107282060B, CN107282065B and CN107282094B disclose that the addition of a certain amount of zirconium oxide, titanium oxide, diatomaceous earth and ZSM-5 molecular sieve as a support modifier during the catalyst preparation process can improve the selectivity and stability of the catalyst in the propylene ammoxidation reaction. However, the catalyst evaluation is also carried out under relatively low load conditions.

[0006] It is generally acknowledged that the specific surface area and the pore size of the catalyst are suitably increased, which helps promote the adsorption and desorption of substrate and product, improves the mass transfer characteristics of the catalyst, and larger pore volume helps the transmission of heat, which is of great significance to promoting the heat conduction efficiency of the catalyst. However, larger pore size in the catalyst often causes the decline in catalyst structural strength, which makes the wear resistance of the catalyst decline, and stability reduction. These above methods show that, by introducing suitable elements, or adding suitable modifiers, although the performance of the catalyst can be improved to a certain extent, still do not have the problem of being able to solve the problem that the current propylene ammoxidation catalyst has a low acrylonitrile yield under high load conditions, poor stability. Summary of the Invention

[0007] The present invention aims to overcome the problems of low target product yield and poor stability of catalysts for ammoxidation reactions in the prior art under high-load conditions, and to provide an ammoxidation catalyst having a large pore size and specific surface area, and having good wear resistance. The catalyst has high unsaturated olefin ammoxidation activity and unsaturated nitrile selectivity in ammoxidation reactions, such as unsaturated olefin ammoxidation reactions, and can maintain a high unsaturated nitrile per-pass yield for a long time under high-load conditions.

[0008] The objectives of the present invention are achieved through the following technical solutions.

[0009] In a first aspect, the present invention provides a catalyst for catalytically synthesizing unsaturated nitriles from unsaturated olefins, characterized in that it comprises a silicon-containing support and an active component, wherein the active component comprises an oxide and / or cationic salt of metal A, an oxide and / or cationic salt of element B, an oxide and / or cationic salt of a rare earth element C, one or more of an oxide, a cationic salt, and an oxyacid salt of a high-valent metal D, an oxide and / or cationic salt of Fe and Bi, and an oxide and / or oxyacid salt of Mo.

[0010] Among them, metal A is selected from at least one of Na, K, Rb and Cs, element B is selected from at least one of Ca, Ba, Mn, Co, Ni, Zn, Mg, Al, Cr, B and P; and high-valent metal D is selected from at least one of Zr(IV), Ti(IV), V(V), Nb(V), and W(IV).

[0011] The cationic salt is a salt composed of the element as a cation and other anions, and the oxyacid salt is a salt composed of the anion of an oxyacid composed of the element and oxygen and other cations. For example, cationic salts of Mo include salts such as molybdenum nitrate and molybdenum sulfate, and oxyacid salts of Mo include salts such as sodium molybdate, potassium molybdate, and ammonium molybdate.

[0012] Wherein, the metal A is selected from at least one of Na, K, Rb and Cs, the element B is selected from at least one of Ca, Ba, Mn, Co, Ni, Zn, Mg, Al, Cr, B and P; the high-valent metal D is selected from at least one of Zr(IV), Ti(IV), V(V), Nb(V), and W(IV). In some embodiments, the active component has the following general formula A a B b C c D d Fe e Bi f Mo 13.6 O x Preferably, the value range of a is 0.01-2.5; the value range of b is 1-15; the value range of c is 0.01-5; the value range of d is 0.1-5; the value range of e is 0.5-10; the value range of f is 0.01-3; and x is the total number of oxygen atoms required to satisfy the valence of each element in the active component.

[0013] In some embodiments, the silicon-containing carrier is silicon dioxide, and the content of the silicon-containing carrier in the catalyst is 30 to 60 wt %, based on the total weight of the catalyst.

[0014] In some embodiments, the specific surface area of ​​the catalyst is 30 to 70 m 2 / g.

[0015] In some embodiments, the catalyst has an average pore diameter of 10 to 20 nm.

[0016] In some embodiments, the catalyst has an average particle size of 20 to 80 μm.

[0017] In some embodiments, the catalyst has an attrition rate of 0.5 to 1.5%.

[0018] In a second aspect, the present invention provides a method for preparing a catalyst, comprising mixing and slurrying solution I and solution II, wherein solution I is an aqueous solution containing a Bi precursor, an Fe precursor, a metal A precursor, an element B precursor, a rare earth element C precursor and a silicon-containing carrier source I; and solution II is a solution containing a Mo precursor, a high-valent metal D precursor and a silicon-containing carrier source II.

[0019] In some embodiments, the Bi precursor, Fe precursor, metal A precursor, element B precursor, and rare earth element C precursor can be oxides of the corresponding elements or any substance that can generate the oxide after calcination, such as oxides, hydroxides, inorganic acid salts and organic acid salts (including hydrates of these compounds) of the corresponding elements, preferably water-soluble inorganic acid salts and water-soluble organic acid salts, more preferably halides, alcohol salts, sulfates, nitrates and acetates, and most preferably nitrates; these precursors can be used alone or in combination in any proportion.

[0020] In some embodiments, the solution II is a solution containing a Mo precursor, a high-valent metal D precursor and a silicon-containing carrier source II. The Mo precursor and the high-valent metal D precursor can be oxides of the corresponding elements or any substance that can generate the oxide after calcination, such as oxides, hydroxides, inorganic acid salts, organic acid salts and ammonium salts of oxygen-containing acids of the corresponding elements, preferably one or more of water-soluble inorganic acid salts, water-soluble organic acid salts or ammonium salts of oxygen-containing acids, more preferably ammonium salts of oxygen-containing acids. The solvent of solution II includes any liquid used in the art to facilitate mixing of raw materials (such as precursors) when synthesizing catalysts, more specifically including alcohol and / or water, especially C1-C6 monohydric alcohol and water, more preferably water.

[0021] The method for preparing the catalyst according to the present invention further comprises aging the solution I and the solution II before mixing.

[0022] In some embodiments, the process further includes spray drying and roasting after pulping.

[0023] In some embodiments, the silicon-containing carrier source I is polysilicic acid and / or polysilicate, preferably polysilicic acid. Preferably, based on the total weight of the silicon-containing carrier, the weight of SiO2 contained in the added silicon-containing carrier source 1 is not higher than 30wt% of the total weight of the silicon-containing carrier, more preferably not higher than 15wt%.

[0024] In some embodiments, the silicon-containing support source II is at least one of silica sol, water glass, silica gel and silicate.

[0025] In some embodiments, the polysilicic acid is typically prepared prior to use, for example, by passing a certain amount of sodium silicate solution through a strong acid cation exchange resin column and adjusting the pH of the mixed solution by adding a dilute sulfuric acid solution. The polysilicic acid used in the present invention has a SiO2 concentration of 1 to 10 wt% and a pH range of 2 to 6.

[0026] In some embodiments, the total solute content of solution I is 20-40 wt%.

[0027] In some embodiments, the total solute content of Solution II is 30-80 wt%.

[0028] In some embodiments, the aging conditions include: a temperature of 10 to 50°C, preferably 20 to 40°C.

[0029] In some embodiments, the aging conditions include: a time of 0.1 to 12 hours, preferably 0.5 to 3 hours.

[0030] In some embodiments, the aging conditions include: a stirring speed of 200 to 800 rpm, preferably 250 to 450 rpm, and more preferably 300 to 400 rpm.

[0031] It should be noted that aging is beneficial for the catalyst to have high unsaturated olefin ammoxidation activity and unsaturated nitrile selectivity while also having good attrition resistance and the like.

[0032] In some embodiments, the pulp cooking conditions include: a temperature of 10 to 80°C, preferably 45 to 70°C.

[0033] In some embodiments, the pulping conditions include: a time of 0.1 to 3 hours, preferably 0.5 to 1.5 hours.

[0034] In some embodiments, the pulp cooking conditions include: a stirring speed of 200 to 1000 rpm, preferably 250 to 500 rpm, and more preferably 250 to 350 rpm.

[0035] In some embodiments, the spray drying conditions include: the drying heat source is air.

[0036] In some embodiments, the spray drying conditions include: a drying temperature of 250-400°C, preferably 300-350°C.

[0037] In some embodiments, the spray drying conditions include: a drying time of 0.5 to 3 hours, preferably 0.5 to 1.5 hours.

[0038] In some embodiments, the spray drying conditions include: the average diameter of the spray droplets is 40 to 200 μm, preferably 40 to 180 μm.

[0039] In some embodiments, the calcination conditions include: in an oxygen-containing atmosphere.

[0040] In some embodiments, the calcination conditions include: a calcination temperature of 200 to 750°C, preferably 300 to 700°C.

[0041] In some embodiments, the calcination conditions include: a calcination time of 2 to 8 hours, preferably 3 to 6 hours.

[0042] According to the present invention, there is no particular limitation on the oxygen content in the oxygen atmosphere. Preferably, the oxygen content in the oxygen-containing atmosphere is greater than 0 and less than 80% by volume, more preferably greater than 0 and less than 50%.

[0043] In a third aspect, the present invention provides use of the catalyst in the preparation of unsaturated nitriles by ammoxidation of unsaturated olefins.

[0044] In some embodiments, the unsaturated olefin is a C2-C5 unsaturated olefin.

[0045] In some embodiments, the invention is used in the synthesis of acrylonitrile by ammoxidation of propylene.

[0046] In some embodiments, propylene undergoes an ammoxidation reaction in the presence of molecular oxygen and ammonia using the ammoxidation catalyst to produce acrylonitrile. According to the present invention, the specifications of propylene, molecular oxygen, and ammonia are not particularly limited. Although the low-molecular-weight saturated hydrocarbon content in the raw propylene does not affect the reaction, from an economic perspective, the propylene concentration is preferably greater than 85 mol%. Fertilizer-grade liquid ammonia can be used as ammonia. From a technical perspective, the molecular oxygen required for the reaction can be pure oxygen, enriched oxygen, or air, but air is preferred for economic and safety reasons.

[0047] In some embodiments, in order to improve the propylene conversion rate and the yield of acrylonitrile, the molar ratio of propylene:ammonia:air is 1:1.0-1.5:8-10.5, preferably 1:1-1.3:8.8-10.

[0048] In some embodiments, in order to improve the propylene conversion rate and the yield of acrylonitrile, the conditions of the ammoxidation reaction are: reaction temperature of 400-470°C, preferably 410-450°C, reaction pressure (gauge pressure) of 0.03-0.15 MPa, preferably 0.06-0.14 MPa, and weight hourly space velocity of 0.045-0.15 h-1, preferably 0.06-0.13 h-1.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The ammonia oxidation catalyst provided by the present invention, by adjusting the active metal components of the catalyst, introduces high-valent elements such as Zr(IV), Ti(IV), V(V), Nb(V), and W(IV), thereby enhancing the stability of the catalyst during calcination and use, preventing the catalyst from sintering, and helping to increase the surface area of ​​the catalyst and improve the catalyst pore size.

[0051] (2) Compared with the preparation method of ammonia oxidation catalyst in the prior art, the preparation method of the improved ammonia oxidation catalyst described in the present invention uses two different silicon-containing carrier sources and adds them to the solution separately through different steps, wherein the silicon-containing carrier source I and the Bi element precursor, the Fe element precursor, the metal A element precursor, the element B precursor, and the rare earth element C precursor can generate a uniformly dispersed stable polysilicate metal salt after aging in the aqueous solution. This is conducive to maintaining a high surface area and a uniform pore size distribution of the catalyst in the subsequent drying and calcination steps, and the average pore diameter of the catalyst can be maintained between 10 and 20 nm, thereby improving the catalytic activity of the catalyst under high load and improving the comprehensive performance of the catalyst. Furthermore, by controlling the weight ratio of SiO2 in the added silicon-containing carrier source I to the total weight of the silicon-containing carrier, the catalyst after spray drying can be made more uniform and have a better bonding effect. Compared with using a single carrier source, the strength of the catalyst can be better improved, thereby improving the wear resistance of the catalyst.

[0052] (3) The ammoxidation catalyst provided by the present invention is used in the preparation of unsaturated nitriles by ammoxidation of unsaturated olefins. It has high unsaturated olefin ammoxidation activity and unsaturated nitrile selectivity. At the same time, the catalyst has a long service life under high load conditions and can maintain a high unsaturated nitrile per-pass yield for a long time, thereby greatly improving the efficiency and economy of unsaturated nitrile production. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 1 is a nitrogen adsorption-desorption curve diagram of the catalysts of Example 1 and Comparative Example 2;

[0054] Figure 2 It is the pore size distribution diagram of the catalyst of Example 1 and Comparative Example 2. DETAILED DESCRIPTION

[0055] In order to make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments and drawings. These embodiments are only for illustration and do not limit the application scope of the present invention.

[0056] In the present invention, the average particle size is measured using a Malvern MS2000 laser particle size analyzer. Before sample measurement, the refractive index of the catalyst must be determined, with SiO2 having a refractive index of 1.45 being used as the refractive index of the catalyst sample. Before sample measurement, the background must be measured. After the measurement, the sample is added to a light shielding level of 10%. Three measurements are performed and the average value is calculated.

[0057] The specific surface area and pore size measurements in this invention are performed using a Tristar physical adsorption instrument. Samples are heated and vacuum degassed before testing. The porosity of the samples is measured at 77K. The specific surface area is calculated using the Brunauer-Emmett-Teller (BET) method. The pore size distribution and pore volume are calculated from the adsorption branch of the isotherm using the Barrettner-Joyner-Halenda (BJH) model.

[0058] The abrasion resistance test method of the present invention is to maintain the system pressure at 0.3 MPa, pass a high-speed stable air flow through the abrasion tester, and continuously purge a 50-gram catalyst sample with a particle size of 160-250 mesh after screening in the abrasion tester. The fine sample is continuously blown from the abrasion zone into the flask extraction tube by elutriation. After 5 hours and 15 hours of continuous purge, the mass of the catalyst in the flask extraction tube is weighed, respectively, W1 and W2, and the catalyst attrition rate is calculated according to the following formula:

[0059] Wear rate (%) = (W2-W1) / (50-W1)×100%

[0060] The activity of the catalyst of the present invention was evaluated in a fluidized bed reactor with an inner diameter of 38 mm. The catalyst loading was 400 g, the reaction temperature was 430°C, the molar ratio of propylene:ammonia:air was 1:1.25:9.7, the reaction pressure (gauge pressure) was 0.085 MPa, and the reaction weight hourly space velocity (WWH) was 0.095 h -1 .

[0061] The conversion of propylene, selectivity of acrylonitrile and single-pass yield are used as indicators for evaluating catalyst performance, and their definitions are as follows:

[0062] Propylene conversion (%) = (moles of propylene consumed in the reaction / moles of propylene fed) × 100%

[0063] Acrylonitrile selectivity (%) = (moles of acrylonitrile produced / moles of propylene consumed in the reaction) × 100%

[0064] Acrylonitrile single-pass yield (%) = (moles of acrylonitrile produced / moles of propylene fed) × 100%

[0065] Example 1

[0066] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 56 m 2 / g, the average pore size is about 14.3nm and evenly distributed, the average particle size is 56μm, and the attrition rate is 0.79%. The nitrogen adsorption-desorption curve of the catalyst is shown in Figure 1 The pore size distribution of the catalyst is shown in Figure 2 .Depend on Figure 1 and Figure 2 As shown in FIG, the catalyst has a larger average pore diameter and a larger specific surface area.

[0067] The activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 99.1%, the acrylonitrile selectivity was 85.1%, and the acrylonitrile per-pass yield was 84.3%. The catalyst composition and performance evaluation parameters are shown in Tables 1 and 2. The other examples and comparative examples are the same.

[0068] Example 2 (Compared with Example 1, the mass of SiO2 in the added polysilicic acid accounts for 5wt% of the total mass of the carrier)

[0069] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 1000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 5 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2375 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 49 m 2 / g, the average pore diameter is about 12.5nm and is evenly distributed, the average particle size is 49μm, and the abrasion rate is 0.85%.

[0070] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 98.9%, the acrylonitrile selectivity was 84.5%, and the acrylonitrile single-pass yield was 83.6%.

[0071] Example 3 (Compared with Example 1, the mass of SiO2 in the added polysilicic acid accounts for 15wt% of the total mass of the carrier)

[0072] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 1500 g of a polysilicic acid solution having a weight concentration of 10 wt % and a pH value of 2.5 was added. The mixture was then stirred at 300 rpm for 2 h and aged to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 15 wt % of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2125 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 53 m 2 / g, the average pore diameter is about 14.6nm and is evenly distributed, the average particle size is 57μm, and the abrasion rate is 0.93%.

[0073] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 99.2%, the acrylonitrile selectivity was 85.3%, and the acrylonitrile single-pass yield was 84.6%.

[0074] Example 4 (Compared with Example 1, the mass of SiO2 in the added polysilicic acid accounts for 25wt% of the total mass of the carrier)

[0075] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2500 g of a polysilicic acid solution having a weight concentration of 10 wt % and a pH value of 2.5 was added. The mixture was then stirred at 300 rpm for 2 h and aged to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 25 wt % of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 1875 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65 ° C and a stirring speed of 300 rpm for 1.5 hours to obtain a slurry. The slurry was spray-dried at a drying temperature of 325 ° C and a drying time of 1 hour. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600 ° C for 4 hours in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 34 m 2 / g, the average pore diameter is about 15.6nm and is evenly distributed, the average particle size is 48μm, and the abrasion rate is 1.16%.

[0076] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 98.8%, the acrylonitrile selectivity was 84.3%, and the acrylonitrile single-pass yield was 83.3%.

[0077] Example 5 (Compared with Example 1, the mass of the carrier accounts for 40 wt% of the total weight of the catalyst)

[0078] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 1333.3 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 1500 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 48 m 2 / g, the average pore diameter is about 12.7nm and is evenly distributed, the average particle size is 56μm, and the abrasion rate is 1.64%.

[0079] The activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 98.0%, the acrylonitrile selectivity was 84.1%, and the acrylonitrile per-pass yield was 82.4%. The catalyst composition and performance evaluation parameters are shown in Tables 1 and 2. The other examples and comparative examples are the same.

[0080] Example 6 (Compared with Example 1, Sm replaces Nd and W replaces Zr)

[0081] 91.0 g of Bi(NO3)3·5H2O, 363.5 g of Ni(NO3)2·6H2O, 181.9 g of Co(NO3)2·6H2O, 110.7 g of Ca(NO3)2·4H2O, 252.5 g of Fe(NO3)3·9H2O, 160.3 g of Mg(NO3)2·6H2O, 9.2 g of RbNO3, and 62.5 g of Sm(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h and aged at 35°C to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 750.4 g of (NH4)6Mo7O 24 4H2O, 81.6 g (NH4) 10 W 12 O 415H2O was dissolved in 250mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250g of silica sol with a weight concentration of 40wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300rpm for 1.5h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1h. The average diameter of the spray droplets was 120μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 52m 2 / g, the average pore diameter is about 13.8nm and is evenly distributed, the average particle size is 57μm, and the abrasion rate is 0.87%.

[0082] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 99.0%, the acrylonitrile selectivity was 84.5%, and the acrylonitrile single-pass yield was 83.9%.

[0083] Example 7 (Compared with Example 1, the contents of Co, Ni, Mg and Zr are different)

[0084] 100.0 g of Bi(NO3)3·5H2O, 249.9 g of Ni(NO3)2·6H2O, 50.0 g of Co(NO3)2·6H2O, 121.8 g of Ca(NO3)2·4H2O, 277.7 g of Fe(NO3)3·9H2O, 132.2 g of Mg(NO3)2·6H2O, 10.1 g of RbNO3, and 67.8 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h and aged at 35°C to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 825.3 g of (NH4)6Mo7O 24 4H2O and 119.2 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 54 m 2 / g, the average pore diameter is about 14.2nm and is evenly distributed, the average particle size is 58μm, and the abrasion rate is 0.93%.

[0085] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 99.0%, the acrylonitrile selectivity was 85.0%, and the acrylonitrile single-pass yield was 84.1%.

[0086] Example 8 (Compared with Example 6, orthogonal experimental design was used to supplement the implementation of the preferred solution)

[0087] 98.8 g of Bi(NO3)3·5H2O, 246.8 g of Ni(NO3)2·6H2O, 49.4 g of Co(NO3)2·6H2O, 120.2 g of Ca(NO3)2·4H2O, 274.3 g of Fe(NO3)3·9H2O, 130.6 g of Mg(NO3)2·6H2O, 67.0 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h and aged at 35°C to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 815.1 g of (NH4)6Mo7O 24 4H2O and 81.4 g of TiOSO4 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65 ° C and a stirring speed of 300 rpm for 1.5 hours to obtain a slurry. The slurry was spray-dried at a drying temperature of 325 ° C and a drying time of 1 hour. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600 ° C for 4 hours in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 51 m 2 / g, the average pore diameter is about 16.3nm and is evenly distributed, the average particle size is 50μm, and the abrasion rate is 0.81%.

[0088] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 99.1%, the acrylonitrile selectivity was 84.3%, and the acrylonitrile single-pass yield was 83.5%.

[0089] Example 9 (Compared with Example 6, orthogonal experimental design was used to supplement the implementation of the preferred solution)

[0090] 94.0 g of Bi(NO3)3·5H2O, 93.9 g of Ni(NO3)2·6H2O, 47.0 g of Co(NO3)2·6H2O, 114.4 g of Ca(NO3)2·4H2O, 522.0 g of Fe(NO3)3·9H2O, 82.8 g of Mg(NO3)2·6H2O, 81.6 g of KNO3, and 63.7 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 3000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h at a temperature of 35°C and aged to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 775.5 g of (NH4)6Mo7O 24 4H2O and 149.4 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 3375 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 59 m 2 / g, the average pore diameter is about 16.5nm and is evenly distributed, the average particle size is 54μm, and the abrasion rate is 0.62%.

[0091] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 98.8%, the acrylonitrile selectivity was 84.5%, and the acrylonitrile single-pass yield was 83.5%.

[0092] Example 10 (Compared with Example 6, orthogonal experimental design was used to supplement the implementation of the preferred solution)

[0093] 97.0 g of Bi(NO3)3·5H2O, 97.0 g of Ni(NO3)2·6H2O, 194.1 g of Co(NO3)2·6H2O, 118.1 g of Ca(NO3)2·4H2O, 404.2 g of Fe(NO3)3·9H2O, 89.5 g of Mn(NO3)2, 13.0 g of CsNO3, and 65.8 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 1333.3 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 800.7 g of (NH4)6Mo7O24 4H2O, 43.5 g (NH4) 10 W 12 O 41 5H2O was dissolved in 250mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 1500g of silica sol with a weight concentration of 40wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300rpm for 1.5h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1h. The average diameter of the spray droplets was 120μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 47m 2 / g, the average pore diameter is about 13.8nm and is evenly distributed, the average particle size is 61μm, and the abrasion rate is 0.86%.

[0094] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 99.2%, the acrylonitrile selectivity was 85.0%, and the acrylonitrile single-pass yield was 84.3%.

[0095] Example 11 (Compared with Example 1, the mass of SiO2 in the added polysilicic acid accounts for 40 wt% of the total mass of the carrier)

[0096] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 4000 g of a polysilicic acid solution having a weight concentration of 10 wt% and a pH value of 2.5 was added. The mixture was then stirred at 300 rpm for 2 h and aged at 35°C to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 40 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 244H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 1500 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 28 m 2 / g, the average pore diameter is about 11.6nm and is evenly distributed, the average particle size is 48μm, and the abrasion rate is 1.23%.

[0097] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 98.3%, the acrylonitrile selectivity was 84.3%, and the acrylonitrile single-pass yield was 82.9%.

[0098] Example 12 (Compared with Example 1, the aging conditions are not within the required range)

[0099] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 80°C and 400 rpm for 3 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1 h. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 30 m 2 / g, the average pore diameter is about 9.5nm and is evenly distributed, the average particle size is 47μm, and the abrasion rate is 1.42%.

[0100] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 98.6%, the acrylonitrile selectivity was 84.3%, and the acrylonitrile single-pass yield was 83.1%.

[0101] Example 13 (Compared with Example 1, the pulping conditions are not within the required range)

[0102] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 120 ° C and a stirring speed of 300 rpm for 4 hours to obtain a slurry. The slurry was spray-dried at a drying temperature of 325 ° C and a drying time of 1 hour. The average diameter of the spray droplets was 120 μm to obtain particles. Finally, the obtained particles were calcined at 600 ° C for 4 hours in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 34 m 2 / g, the average pore diameter is about 10.2nm and is evenly distributed, the average particle size is 49μm, and the abrasion rate is 1.35%.

[0103] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 98.7%, the acrylonitrile selectivity was 84.0%, and the acrylonitrile single-pass yield was 82.9%.

[0104] Example 14 (compared with Example 1, spray drying is not within the required range)

[0105] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 24 4H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 340°C and a drying time of 1 h. The average diameter of the spray droplets was 250 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 33 m 2 / g, the average pore diameter is about 11.5nm and is evenly distributed, the average particle size is 96μm, and the abrasion rate is 1.68%.

[0106] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 97.3%, the acrylonitrile selectivity was 83.2%, and the acrylonitrile single-pass yield was 81.0%.

[0107] Comparative Example 1 (not applicable to polysilicic acid solution)

[0108] 100.4 g of Bi(NO3)3·5H2O, 301.0 g of Ni(NO3)2·6H2O, 100.4 g of Co(NO3)2·6H2O, 122.2 g of Ca(NO3)2·4H2O, 278.8 g of Fe(NO3)3·9H2O, 88.5 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.1 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 250 g of silica sol with a weight concentration of 40 wt% was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 828.5 g of (NH4)6Mo7O 244H2O and 79.8 g of ZrO(NO3)2 were dissolved in 250 mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250 g of silica sol with a weight concentration of 40 wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300 rpm for 1.5 h to obtain a slurry. The slurry was spray-dried at a drying temperature of 340°C and a drying time of 1 h. The average diameter of the spray droplets was 250 μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4 h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 43 m 2 / g, the average pore size is about 9.1nm and evenly distributed, the average particle size is 62μm, and the attrition rate is 1.43%. The nitrogen adsorption-desorption curve of the catalyst is shown in Figure 1 The pore size distribution of the catalyst is shown in Figure 2 .Depend on Figure 1 and Figure 2 As shown, when the catalyst only uses silica sol as the silicon-containing support source, the catalyst pore diameter is small and the specific surface area is low, which is not conducive to the diffusion of substrate and product molecules on the catalyst surface.

[0109] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 97.6%, the acrylonitrile selectivity was 84.6%, and the acrylonitrile single-pass yield was 82.6%.

[0110] Comparative Example 2 (without adding any high-price metal D)

[0111] 100.6 g of Bi(NO3)3·5H2O, 301.4 g of Ni(NO3)2·6H2O, 100.5 g of Co(NO3)2·6H2O, 122.4 g of Ca(NO3)2·4H2O, 279.2 g of Fe(NO3)3·9H2O, 88.6 g of Mg(NO3)2·6H2O, 10.2 g of RbNO3, and 68.2 g of Nd(NO3)3·6H2O were dissolved in 100 mL of water, and then 2000 g of a polysilicic acid solution having a weight concentration of 5 wt% and a pH value of 3 was added. The mixture was then stirred at 300 rpm for 2 h for aging to obtain a mixed solution I. The weight of SiO2 contained in the added polysilicic acid was 10 wt% of the total weight of the carrier. 829.6 g of (NH4)6Mo7O 244H2O was dissolved in 250mL of water to obtain a mixed solution II. Then, the mixed solution I, the mixed solution II and 2250g of silica sol with a weight concentration of 40wt% were mixed, and then the mixture was stirred at a temperature of 65°C and a stirring speed of 300rpm for 1.5h to obtain a slurry. The slurry was spray-dried at a drying temperature of 325°C and a drying time of 1h. The average diameter of the spray droplets was 120μm to obtain particles. Finally, the obtained particles were calcined at 600°C for 4h in an oxygen-containing atmosphere (oxygen volume fraction 21%) to obtain a catalyst. The specific surface area of ​​the catalyst is 48m 2 / g, the average pore diameter is about 13.6nm and is evenly distributed, the average particle size is 58μm, and the abrasion rate is 1.65%.

[0112] Activity evaluation of the catalyst showed that the propylene conversion rate of the catalyst was 96.5%, the acrylonitrile selectivity was 83.2%, and the acrylonitrile single-pass yield was 80.3%.

[0113] Table 1 Composition and properties of ammonia oxidation catalyst

[0114]

[0115] Table 2 Ammonia oxidation catalyst attrition rate and activity evaluation results

[0116]

[0117] According to the results of Examples 1 to 14 and Comparative Examples 1 and 2, the addition of any D element within the range specified by the present invention and the controlled addition of different silicon-containing supports during the preparation of the ammoxidation catalyst can increase the specific surface area and average pore diameter of the catalyst while maintaining a low catalyst attrition rate, thereby enabling the catalyst to maintain good mechanical stability under high-load conditions. The larger specific surface area also helps improve the thermal conductivity of the catalyst, thereby enabling the catalyst to exhibit a higher single-pass yield of acrylonitrile in the propylene ammoxidation reaction under high-load conditions.

[0118] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, under the technical enlightenment provided by the present invention, as common knowledge in the art, other equivalent variations and improvements can be made, which should also be considered as the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for catalytic synthesis of unsaturated nitriles from unsaturated olefins, characterized in that: The method comprises mixing solution I, solution II and silicon-containing carrier source II and boiling them into slurry, wherein the solution I is an aqueous solution containing Bi precursor, Fe precursor, metal A precursor, element B precursor, rare earth element C precursor and silicon-containing carrier source I; The solution II is a solution containing a Mo precursor and a high-valent metal D precursor; Wherein, the metal A is selected from at least one of Na, K, Rb and Cs, the element B is selected from at least one of Ca, Ba, Mn, Co, Ni, Zn, Mg, Al, Cr, B and P; the high-valent metal D is selected from at least one of Zr(IV), Ti(IV), V(V), Nb(V) and W(IV); The silicon-containing carrier source I is polysilicic acid and / or polysilicate; The preparation method further comprises aging the solution I before mixing; The silicon-containing carrier source II is at least one of silica sol, water glass, silica gel and silicate; The general formula of the active ingredient is as follows: a B b C c D d Fe e Bi f Mo 13.6 O x , wherein the value range of a is 0.01 to 2.5; the value range of b is 1 to 15; the value range of c is 0.01 to 5; the value range of d is 0.1 to 5; the value range of e is 0.5 to 10; the value range of f is 0.01 to 3; and x is the total number of oxygen atoms required to satisfy the valence of each element in the active component.

2. The method for preparing the catalyst according to claim 1, wherein The aging conditions include: a temperature of 10 to 50° C., and / or a time of 0.1 to 12 hours, and / or a stirring speed of 200 to 800 rpm.

3. The method for preparing the catalyst according to claim 1, wherein It also includes spray drying and roasting after pulping.

4. The method for preparing the catalyst according to claim 3, wherein The spray drying conditions include: the drying heat source is air, the drying temperature is 250-400°C, the drying time is 0.5-3h, and / or the average diameter of the spray droplets is 40-200μm; And / or the calcination conditions include: in an oxygen-containing atmosphere, a calcination temperature of 200-750° C., and / or a calcination time of 2-8 hours.

5. The method for preparing the catalyst according to any one of claims 1 to 4, characterized in that: The silicon-containing carrier source I is polysilicic acid; And / or based on the total weight of the silicon-containing carrier, the weight of SiO2 contained in the added silicon-containing carrier source I is not higher than 30wt% of the total weight of the silicon-containing carrier.

6. The method for preparing the catalyst according to claim 5, characterized in that: Based on the total weight of the silicon-containing carrier, the weight of SiO2 contained in the added silicon-containing carrier source I is not higher than 15wt% of the total weight of the silicon-containing carrier.

7. The method for preparing the catalyst according to any one of claims 1 to 4, characterized in that: The pulping conditions include: a temperature of 10 to 80° C., and / or a time of 0.1 to 3 hours, and / or a stirring speed of 200 to 1000 rpm.

8. A catalyst for catalytic synthesis of unsaturated nitriles from unsaturated olefins, prepared by the preparation method according to any one of claims 1 to 7.

9. The catalyst according to claim 8, characterized in that The invention comprises a silicon-containing carrier and an active component, wherein the active component comprises an oxide and / or a cationic salt of metal A, an oxide and / or a cationic salt of element B, an oxide and / or a cationic salt of a rare earth element C, one or more oxides, cationic salts and oxygen-containing acid salts of a high-valent metal D, oxides and / or cationic salts of Fe and Bi, and oxides and / or oxygen-containing acid salts of Mo.

10. The catalyst according to claim 9, characterized in that The silicon-containing carrier is silicon dioxide, and the content of the silicon-containing carrier in the catalyst is 30-60 wt % based on the total weight of the catalyst.

11. The catalyst according to claim 9 or 10, characterized in that The specific surface area of ​​the catalyst is 30 to 70 m 2 / g; and / or an average pore diameter of 10 to 20 nm; and / or an average particle size of 20 to 80 μm; and / or an abrasion rate of 0.5 to 1.5%.

12. Use of the catalyst according to any one of claims 8 to 11 in the preparation of unsaturated nitriles by ammoxidation of unsaturated olefins.

13. The use according to claim 12, characterized in that The unsaturated olefin is a C2-C5 unsaturated olefin; And / or, the application is in the reaction of synthesizing acrylonitrile by ammoxidation of propylene.

Images