Ammonia oxidation catalysts, methods of making and using the same, and processes for the production of acrylonitrile by the ammonia oxidation of propylene

Abstract

The present application relates to the field of catalysis, in particular to an ammoxidation catalyst, a preparation method and application thereof, and a method for preparing acrylonitrile by propylene ammoxidation, the catalyst has an active component with a general formula of Mo a Bi b Fe c X d Y e Z f N g O h The H2-TPR spectrum of the catalyst contains at least two reduction peaks; the highest peak position of the first reduction peak is lower than 560 DEG C, and the difference between the end peak temperature and the start peak temperature of the first reduction peak is ≤200 DEG C; the catalyst has low-temperature activity and high stability in the reaction of preparing acrylonitrile by propylene ammoxidation.

Description

Technical Field

[0001] This invention relates to the field of catalysis, and more particularly to an ammonia oxidation catalyst, its preparation method and application, and a method for the ammonia oxidation of propylene to acrylonitrile. Background Technology

[0002] Acrylonitrile (AN) is a raw material monomer used in the synthesis of acrylic fibers. It is also a raw material for thermoplastic synthetic resins such as ABS and SAN, nitrile rubber, adiponitrile, acrylamide, and other derivatives, making it one of the important petrochemical products. The process technology for producing acrylonitrile through the ammoxidation of propylene has become increasingly mature, and the development of high-performance acrylonitrile catalysts is a hot topic in the acrylonitrile industry.

[0003] Currently, the industrial production of unsaturated nitriles from olefins through ammoxidation still widely adopts fluidized bed ammoxidation. Catalysts, as one of the core technologies of this process, have received significant attention for research and improvement. Currently, there are two main types of catalysts for the industrial ammoxidation of propylene to acrylonitrile: Mo-Bi and Sb-based, with Mo-Bi catalysts dominating, accounting for 95% of the olefin oxidation market. Previous research and exploration have primarily focused on Mo-Bi catalysts. Introducing metal components with variable valence states, such as Fe and Ce, into the catalyst can improve its redox performance and accelerate the recovery of the effective state of the active components. Introducing metal elements with ionic radii greater than 0.8 nm and less than 0.8 nm, such as Cr, Ni, Mg, Mn, Zn, and Al, can act as structural and electronic aids, improving the catalyst's structure and stability. Introducing rare earth elements can increase the number of lattice oxygen atoms in the catalyst, improving its catalytic performance. Introducing elements such as Cs, Rb, P, B, and Al can modify the surface of the catalyst and adjust its acidity and basicity, improving its selectivity and activity.

[0004] CN110557941A proposes that by controlling the composition and state of specific peaks in X-ray diffraction analysis, the catalyst exhibits higher ammonia conversion and improves the yield of acrylonitrile and hydrogen cyanide, which are the ammoxidation products of acrylonitrile.

[0005] CN113692315A proposes that by controlling the composition of specific phases in X-ray analysis, the yield of hydrogen cyanide can be increased while suppressing the decrease in acrylonitrile yield. However, none of the above studies have addressed the further redox performance of the catalyst. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of high reaction temperature and poor long-term stability of existing catalysts, and to provide an ammonia oxidation catalyst, its preparation method and application, as well as a method for the ammonia oxidation of propylene to acrylonitrile. This catalyst has the characteristics of low activation starting temperature and uniform distribution of active components. When used in ammonia oxidation, especially the ammonia oxidation of propylene to acrylonitrile, it has the characteristics of high low-temperature activity and excellent stability.

[0007] To achieve the above objectives, the present invention provides an ammonia oxidation catalyst having the general formula Mo. a Bi b Fe c X d Y e Z f N g O h The active component is selected from at least one rare earth element; Y is selected from at least one alkali metal element; Z is selected from at least one alkaline earth metal element; N is selected from at least one of W, V, Zr, P, Nb, Ni, Co, Cr, Mn, Ti, Au, Ag, Pt, Ru, Rh, Pd, Ti, Sb, In, Sn, and Te; the atomic ratio of b to a is 0.008-0.25; the atomic ratio of c to b is 1.0-12.0; the atomic ratio of the sum of d, e, and f to a is 0.05-0.4; the atomic ratio of g to a is 0.01-1.0; h is determined by the atomic ratio and valence state of elements other than oxygen; the H2-TPR spectrum of the catalyst contains at least two reduction peaks; in the H2-TPR spectrum of the catalyst, the difference between the end temperature and the start temperature of the first reduction peak is ≤200℃; the highest peak temperature of the first reduction peak is below 560℃.

[0008] A second aspect of the present invention provides a method for preparing an ammonia oxidation catalyst, the method comprising:

[0009] S1. Mix the first part of the Mo source, Fe source and X source under solution conditions to form solution I;

[0010] S2. Mix the Z source, Bi source, Y source, and N source under solution conditions to form solution II;

[0011] S3. The carrier source and the second part of the Mo source are mixed under solution conditions to form mixture I;

[0012] S4. Mix solution I with mixture I to obtain mixture II;

[0013] S5. Mix solution II with mixture II to obtain a slurry, heat treat the slurry, shape it, and calcine it.

[0014] A third aspect of the present invention provides the ammonia oxidation catalyst described herein and its application in the ammonia oxidation reaction of olefins.

[0015] A fourth aspect of the present invention provides a method for the ammoxidation of propylene to acrylonitrile, the method comprising: contacting a propylene feedstock, an oxygen source and an ammonia source in the presence of the catalyst described in the present invention.

[0016] Through the above technical solution, the present invention has the following beneficial effects:

[0017] The ammonia oxidation catalyst of the present invention has the general formula Mo. a Bi b Fe c X d Y e Z f N g O h The active component; wherein, X is selected from at least one rare earth element; Y is selected from at least one alkali metal element; Z is selected from at least one alkaline earth metal element; N is selected from at least one of W, V, Zr, P, Nb, Ni, Co, Cr, Mn, Ti, Au, Ag, Pt, Ru, Rh, Pd, Ti, Sb, In, Sn, and Te; the atomic ratio of b to a is 0.008-0.25; the atomic ratio of c to b is 1.0-12.0; the sum of d, e, and f and the atomic ratio of a are... The atomic ratio is 0.05-0.4; the atomic ratio of g to a is 0.01-1.0; h is determined by the atomic ratio and valence state of elements other than oxygen; the H2-TPR spectrum of the catalyst contains at least two reduction peaks; in the H2-TPR spectrum of the catalyst, the difference between the end temperature and the beginning temperature of the first reduction peak is ≤200℃; the highest temperature of the first reduction peak is below 560℃. It is used in the reaction of ammonia oxidation, especially the ammonia oxidation of propylene to acrylonitrile, and has the characteristics of high low-temperature activity and excellent stability. Attached Figure Description

[0018] Figure 1 The H2-TPR spectrum of the catalyst prepared in Example 1 is shown. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] This invention provides an ammonia oxidation catalyst having the general formula Mo. a Bib Fe c X d Y e Z f N g O h The active component is selected from at least one rare earth element; Y is selected from at least one alkali metal element; Z is selected from at least one alkaline earth metal element; N is selected from at least one of W, V, Zr, P, Nb, Ni, Co, Cr, Mn, Tl, Au, Ag, Pt, Ru, Rh, Pd, Ti, Sb, In, Sn, and Te; the atomic ratio of b to a is 0.008-0.25; the atomic ratio of c to b is 1.0-12.0; the atomic ratio of the sum of d, e, and f to a is 0.05-0.4; the atomic ratio of g to a is 0.01-1.0; h is determined by the atomic ratio and valence state of elements other than oxygen; the H2-TPR spectrum of the catalyst contains at least two reduction peaks; in the H2-TPR spectrum of the catalyst, the difference between the end temperature and the start temperature of the first reduction peak is ≤200℃; the highest peak temperature of the first reduction peak is below 560℃.

[0021] The ammonia oxidation catalyst of the present invention is used in the ammonia oxidation, especially the ammonia oxidation of propylene to acrylonitrile reaction, and has the characteristics of high activity at low temperature and excellent stability.

[0022] According to a particularly preferred embodiment of the present invention, in the H2-TPR spectrum of the ammonia oxidation catalyst, the difference between the end temperature and the start temperature of the first reduction peak is ≤180℃. In the present invention, the end position of the first reduction peak is the start position of the second reduction peak, thus, the H2-TPR spectrum of the catalyst of the present invention contains at least two reduction peaks.

[0023] According to a particularly preferred embodiment of the present invention, the elution temperature of the first reduction peak of the ammonia oxidation catalyst is below 540°C.

[0024] According to a particularly preferred embodiment of the present invention, the particle size of the ammonia oxidation catalyst is 40-60 μm, preferably 45-55 μm. By adopting the aforementioned preferred embodiment, the flowability of the catalyst in the reactor, especially in a fluidized bed reactor, can be further improved.

[0025] According to a particularly preferred embodiment of the present invention, the atomic ratio of b to a in the general formula of the catalyst is 0.1-0.22.

[0026] According to a particularly preferred embodiment of the present invention, the atomic ratio of c to b in the general formula of the catalyst is 3-10.

[0027] According to a particularly preferred embodiment of the present invention, the atomic ratio of the sum of d, e and f to a in the general formula of the catalyst is 0.20-0.35.

[0028] According to a particularly preferred embodiment of the present invention, the atomic ratio of g to a in the general formula of the catalyst is 0.5-0.7.

[0029] By adopting the aforementioned preferred embodiments, the performance of the ammonia oxidation catalyst can be further improved.

[0030] According to a particularly preferred embodiment of the present invention, X is selected from at least one of La, Ce, Pr, Nd, and Sm, preferably at least one of La, Pr, Ce, and Nd.

[0031] According to a particularly preferred embodiment of the present invention, the Y is selected from at least one of Li, Na, K, Rb and Cs, preferably at least one of K, Cs and Rb.

[0032] According to a particularly preferred embodiment of the present invention, Z is selected from at least one of Be, Mg, Ca, Sr and Ba, preferably Mg and / or Ca.

[0033] According to a particularly preferred embodiment of the present invention, the N is selected from at least one of W, Zr, P, Nb, Ni, Co, Cr, Ag, Mn and In.

[0034] According to a particularly preferred embodiment of the present invention, the catalyst support includes at least one of silicon oxide, zirconium oxide, cerium oxide, and titanium oxide.

[0035] According to a particularly preferred embodiment of the present invention, the average particle size distribution of the carrier is 5-35 nm.

[0036] According to a particularly preferred embodiment of the present invention, the catalyst contains 10-90% by weight of support and 10-90% by weight of active component, based on the total weight of the catalyst.

[0037] By adopting the aforementioned preferred embodiments, the performance of the ammonia oxidation catalyst can be further improved.

[0038] Catalysts possessing the aforementioned characteristics can all be used in this invention, and there are no special requirements for their preparation methods. Specifically, this invention provides a method for preparing an ammonia oxidation catalyst, the method comprising:

[0039] S1. Mix the first part of the Mo source, Fe source and X source under solution conditions to form solution I;

[0040] S2. Mix the Z source, Bi source, Y source, and N source under solution conditions to form solution II;

[0041] S3. The carrier source and the second part of the Mo source are mixed under solution conditions to form mixture I;

[0042] S4. Mix solution I with mixture I to obtain mixture II;

[0043] S5. Mix solution II with mixture II to obtain a slurry. Heat-treat the slurry, shape it, and calcine it. In this invention, there are no special requirements for the source of the active component; as long as it can achieve the purpose of this invention, it is acceptable. Existing technologies can be referenced. The Mo source, Bi source, Fe source, X source, Y source, Z source, and N source are each selected from corresponding metal compounds, preferably corresponding metal salts.

[0044] In this invention, there are no special requirements for the solvent of the solution in the catalyst preparation step. As long as the purpose of this invention can be achieved, it can be carried out with reference to the prior art. The solvent of the solution in this invention is selected from deionized water.

[0045] In this invention, the carrier source mentioned in step S3 can be a conventional choice in the art. Taking silica as an example, according to a preferred embodiment of the present invention, the carrier source includes at least one of silica sol, silica aerogel, and pure silica molecular sieve, preferably silica sol, and more preferably silica sol with a solid content of 20-50 wt%.

[0046] In this invention, the ratio of the first Mo source to the second Mo source in the catalyst preparation step can be selected within a wide range. According to a preferred embodiment of this invention, the ratio of the first Mo source to the second Mo source is 1:(0.5-1.5). By adopting the aforementioned preferred embodiment, the low-temperature activity and stability of the catalyst can be further improved.

[0047] In this invention, there are no special requirements for the mixing method of S1-S5, and it can be carried out with reference to the prior art.

[0048] According to a preferred embodiment of the present invention, the mixing method is preferably dynamic mixing.

[0049] In this invention, the mixing conditions in S1 can be conventional choices in the art, as illustrated below, but are not intended to limit the scope of the invention.

[0050] According to a preferred embodiment of the present invention, the solid content of solution I in S1 is 15-30% by weight.

[0051] According to a preferred embodiment of the present invention, the mixing temperature in S1 is 30-80°C.

[0052] According to a preferred embodiment of the present invention, the mixing time in S1 is 10-40 min.

[0053] By adopting the aforementioned preferred embodiments, the stability of the active phase can be further improved.

[0054] In this invention, the mixing conditions in S2 can be conventional choices in the art, as illustrated below, but are not intended to limit the scope of the invention.

[0055] According to a preferred embodiment of the present invention, the solid content of solution II in S2 is 15-40% by weight.

[0056] According to a preferred embodiment of the present invention, the mixing temperature in S2 is 30-80°C.

[0057] According to a preferred embodiment of the present invention, the mixing time in S2 is 10-40 min.

[0058] By adopting the aforementioned preferred embodiments, the stability of the corresponding active phase can be further improved.

[0059] In this invention, the mixing conditions in S3 can be conventional choices in the art, as illustrated below, but are not intended to limit the scope of the invention.

[0060] According to a preferred embodiment of the present invention, the solid content of mixture I in S3 is 20-40% by weight.

[0061] According to a preferred embodiment of the present invention, the mixing temperature in S3 is 25-50°C.

[0062] According to a preferred embodiment of the present invention, the mixing time in step S3 is 5-10 minutes.

[0063] By adopting the aforementioned preferred embodiments, the dispersibility of the active component on the carrier can be further improved.

[0064] In this invention, the mixing conditions in S4 can be conventional choices in the art, as illustrated below, but are not intended to limit the scope of the invention.

[0065] According to a preferred embodiment of the present invention, the mixing temperature in step S4 is 25-40°C.

[0066] According to a preferred embodiment of the present invention, the mixing time in S4 is 10-30 min.

[0067] By adopting the aforementioned preferred embodiments, the uniform distribution of different active phases can be further improved, which is beneficial to the formation of solid solutions.

[0068] In this invention, the mixing conditions in S5 can be conventional choices in the art, as illustrated below, but are not intended to limit the scope of the invention.

[0069] According to a preferred embodiment of the present invention, the mixing temperature in step S5 is 25-40°C.

[0070] According to a preferred embodiment of the present invention, the mixing time in step S5 is 10-30 min.

[0071] By adopting the aforementioned preferred embodiments, the dispersion degree of different active phases can be further improved.

[0072] In this invention, the heat treatment conditions for the slurry in step S5 can be conventional choices in the art, as illustrated below, but are not intended to limit the scope of the invention.

[0073] According to a preferred embodiment of the present invention, the heat treatment heating rate of the slurry is 8-15℃ / min.

[0074] According to a preferred embodiment of the present invention, the heat treatment temperature of the slurry is 100-150°C.

[0075] According to a preferred embodiment of the present invention, the heat treatment time of the slurry is 5-30 minutes.

[0076] In this invention, the drying and calcination conditions are not particularly required and can be carried out with reference to existing technology. The following is an illustrative description, but it does not limit the scope of this invention.

[0077] According to a preferred embodiment of the invention, both the drying and calcination are carried out in an oxygen-containing gas, as illustrated below, but without limiting the scope of the invention.

[0078] In this invention, the molding method has no special requirements and can be carried out with reference to existing technology. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the molding method is spray drying.

[0079] In this invention, the molding conditions can be conventional choices in the art, as illustrated below, but are not intended to limit the scope of the invention.

[0080] According to a preferred embodiment of the present invention, the spray drying temperature is 250-350°C, preferably 300-350°C.

[0081] According to a preferred embodiment of the present invention, the spray drying time is 0.1-2.0 h, preferably 0.2-1.0 h.

[0082] According to a preferred embodiment of the present invention, the diameter of the spray droplets during the spray drying process is 20-200 μm, preferably 40-180 μm.

[0083] In this invention, the calcination conditions can be conventionally chosen in the art, as illustrated below, but do not limit the scope of the invention. According to a preferred embodiment of the invention, the calcination conditions are as follows: heating to 250-400°C at a heating rate of 5-20°C / min and holding for 10-60 min, then heating to 400-700°C at a heating rate of 5-20°C / min and holding for 20-90 min.

[0084] This invention provides an ammonia oxidation catalyst prepared by the preparation method described herein.

[0085] This invention provides the application of the ammonia oxidation catalyst described herein in the ammonia oxidation reaction of olefins. According to a preferred embodiment of the invention, the olefin is selected from propylene and / or isobutylene.

[0086] The present invention provides a method for producing acrylonitrile by ammoxidation of propylene, the method comprising: contacting a propylene feedstock, an oxygen source and an ammonia source in the presence of the catalyst described in the present invention.

[0087] In this invention, the contact conditions in the ammoxidation of propylene to acrylonitrile can be conventionally selected in the art.

[0088] According to a preferred embodiment of the present invention, the oxygen source in the contact condition is an oxygen-containing gas, preferably with an oxygen volume content of 20-30%.

[0089] According to a preferred embodiment of the present invention, the contact is carried out in a fluidized bed reactor.

[0090] According to a preferred embodiment of the present invention, in the contact conditions, the molar ratio of propylene feedstock (based on propylene), ammonia source (based on NH3), and oxygen source (based on O2) is 1:(1.1-1.35):(1.8-2.5).

[0091] According to a preferred embodiment of the present invention, the contact temperature is 420-440°C.

[0092] According to a preferred embodiment of the present invention, the contact pressure is 0.03-0.14 MPa.

[0093] According to a preferred embodiment of the present invention, the contact gravity hourly space velocity is 0.04-0.10 h⁻¹. -1 .

[0094] In this invention, the amount of catalyst loaded in the ammoxidation of propylene to produce acrylonitrile is determined according to actual operational needs, without any special requirements.

[0095] In this invention, the catalyst composition is based on the composition calculated from the amount of feed.

[0096] In this invention, particle size is measured using a Malvern MS2000 laser particle size analyzer.

[0097] Before testing the samples, the circulating water in the device needs to be turned on;

[0098] Before sample measurement, the refractive index of the catalyst needs to be selected. The refractive index of SiO2 is 1.45, which is used as the refractive index of the sample to be measured.

[0099] Before measuring the sample, the background needs to be measured. After the measurement, the sample is added up to 10% of the shading level. Three measurements are taken and the average value is selected.

[0100] In this invention, H2-TPR (H2-TPR spectrum, H2-programmed temperature reduction) was performed using an AutoChem II 2920 from Micron Instruments, USA. The carrier gas composition was 5% H2 + 95% Ar, the carrier gas flow rate was 20 mL / min, and the sample volume was 0.05 g. The sample was purged with Ar gas at 673 K for 1 h, cooled to 323 K, and then subjected to a flow rate of 10 K·min. -1 The temperature was increased to 923K at a certain heating rate, and the reduction performance of the sample was detected by a TCD detector.

[0101] The method for calculating propylene conversion rate is as follows:

[0102] Propylene conversion rate = (total carbon moles of each component - carbon moles of unreacted propylene) / total carbon moles of each component × 100%;

[0103] Acrylonitrile yield = (number of carbon moles of acrylonitrile produced / total number of corresponding carbon moles of each component) × 100%.

[0104] Example 1

[0105] S1. 419.2 grams of (NH4)6Mo7O 24 ·4H2O was dissolved in deionized water, and 642.7 g of Fe(NO3)3·9H2O and 76 g of Pr(NO3)3·6H2O were added. The solid content was 25% by mass. The mixing temperature was 60℃ and the mixture was stirred for 20 min to form solution I.

[0106] S2. Dissolve 3.59 g KOH, 171.3 g Bi(NO3)3·5H2O, 518.7 g Ni(NO3)2·6H2O, and 135.8 g Mg(NO3)2·6H2O in deionized water, with a solid content of 27% by mass. Mix at 60°C and stir for 20 min to form solution II.

[0107] S3. 395.5 grams of (NH4)6Mo7O 24 • Dissolve 4H2O in deionized water, add 2750 g of silica sol with a weight concentration of 40%, mix at 30°C, stir for 5 min, and the solid content is 30% by mass to form mixture I;

[0108] S4. Add solution I to mixture I and stir. The mixing temperature is 30℃ and the stirring time is 20min to form mixture II.

[0109] S5. Add solution II to mixture II and stir at 30℃ for 20 min to form a slurry. Increase the temperature of the slurry to 150℃ at a rate of 10℃ / min and hold for 15 min. Perform microsphere forming on the prepared slurry in a spray dryer at 300℃ for 0.5 h, resulting in an average droplet diameter of 100 μm, to obtain particulate matter. Finally, calcine in air at a rate of 5℃ / min to 300℃, hold for 30 min, then increase the temperature to 550℃ at 20℃ / min and hold for 45 min. The composition of the catalyst obtained according to the above steps is expressed by the following formula:

[0110] 50% K 0.15 Fe 4.46 Ni 5.0 Mg 1.5 Pr 0.5 La 1.0 Bi 1.0 Mo 13 O x +50% SiO2

[0111] The results of H2-TPR spectrum measurement are as follows Figure 1 As shown, the first reduction peak is located at 525℃. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak is 145℃.

[0112] S6. The reaction conditions for the ammoxidation of propylene to acrylonitrile using the above catalyst are as follows:

[0113] In a millimeter-sized fluidized bed reactor, the catalyst particle size was 100 micrometers, the reaction temperature was 430℃, the reaction pressure was 0.084 MPa, the catalyst loading was 300 g, and the catalyst propylene loading (WWH, weight hourly space velocity) was 0.085 h⁻¹.-1 Raw material ratio (moles): C3 = NH3 / air = 1 / 1.25 / 2.0. After running for 500 hours.

[0114] The reaction results are as follows: propylene conversion rate was 98.8%, and acrylonitrile yield was 82.8%.

[0115] Example 2

[0116] (1) Preparation of ammonia oxidation catalyst

[0117] S1. 451.3 grams of (NH4)6Mo7O 24 Dissolve 4H2O in deionized water, then add 692 g of Fe(NO3)2O. 3)3 ·9H2O, 45.3 g La(NO3)3·6H2O and 82.6 g Nd(NO3)3·6H2O, with a solid content of 20% by mass, were mixed at 80℃ and stirred for 10 min to form solution I;

[0118] S2. Dissolve 3.86 g KOH, 92.2 g Bi(NO3)3·5H2O, 442.6 g Co(NO3)2·6H2O, 146.2 g Mg(NO3)2·6H2O, 3.84 g CrO3, and 134.7 g Mn(NO3)2 in deionized water to obtain a solid content of 25% by mass. Mix at 80°C and stir for 10 min to form solution II.

[0119] S3. 425.7 grams of (NH4)6Mo7O 24 • Dissolve 4H2O in deionized water, add 2750 g of silica sol with a weight concentration of 40%, stir for 30 min, the solid content is 30% by mass, the mixing temperature is 30℃, stir for 5 min, and a mixture I is formed.

[0120] S4. Add solution I to mixture I and stir. The mixing temperature is 40℃ and the stirring time is 30min to form mixture II.

[0121] S5. Add solution II to mixture II and stir. The mixing temperature is 40℃ and the mixing time is 10 min to form a slurry. Increase the temperature of the slurry to 150℃ at a rate of 15℃ / min and hold for 10 min. Perform microsphere forming on the prepared slurry in a spray dryer at 300℃ for 0.5 h, resulting in an average droplet diameter of 100 μm, to obtain particulate matter. Finally, calcine in air at a rate of 10℃ / min to 300℃, hold for 20 min, then increase the temperature to 550℃ at a rate of 10℃ / min and hold for 60 min. The composition of the catalyst obtained according to the above steps is expressed by the following formula:

[0122] 50% Cr0.1 K 0.15 Fe 4.46 Co 4.0 Mn 1.0 Mg 1.5 Nd 0.5 La 0.3 Bi 0.5 Mo 13 O x +50% SiO2

[0123] The peak elution is similar to that in Example 1, except that the first reduction peak is located at 530°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the elution peak is 150°C.

[0124] The evaluation method is the same as S6 in Example 1.

[0125] The reaction results are as follows: propylene conversion rate was 98.1%, and acrylonitrile yield was 82.5%.

[0126] Example 3

[0127] (1) Preparation of ammonia oxidation catalyst

[0128] S1. 565.1 grams of (NH4)6Mo7O 24 • Dissolve 4H2O in deionized water, then add 866.6 g of Fe(NO3)2O. 3)3 ·9H2O, 105.4 g La(NO3)3·6H2O and 69.2 g Ce(NO3)3·6H2O, with a solid content of 20% by mass, were mixed at 40℃ and stirred for 30 min to form solution I;

[0129] S2. Dissolve 11.74 g RbNO3, 128.7 g Bi(NO3)3·5H2O, 772.5 g Co(NO3)2·6H2O, 188 g Ca(NO3)2·6H2O, 6.54 g ZrO2, and 5.36 g CrO3 in deionized water to obtain a solid content of 25% by mass. Mix at 40°C and stir for 30 min to form solution II.

[0130] S3. 659.3 grams of (NH4)6Mo7O 24 • Dissolve 4H2O in deionized water, add 1650 g of silica sol with a weight concentration of 40%, mix at 30°C, stir for 10 min, and the solid content is 35% by mass to form mixture I.

[0131] S4. Add solution I to mixture I and stir. The mixing temperature is 40℃ and the stirring time is 30min to form mixture II.

[0132] S5. Add solution II to mixture II and stir at 40℃ for 30 min to form a slurry. Increase the temperature of the slurry to 150℃ at a rate of 10℃ / min and hold for 15 min. Perform microsphere forming on the prepared slurry in a spray dryer at 300℃ for 0.5 h, resulting in an average droplet diameter of 100 μm, to obtain particulate matter. Finally, calcine in air at a rate of 20℃ / min to 300℃, hold for 60 min, then increase the temperature to 550℃ at 20℃ / min and hold for 30 min. The composition of the catalyst obtained according to the above steps is expressed by the following formula:

[0133] 70% Zr 0.1 Rb 0.15 Fe 4.0 Co 5.0 Cr 0.1 Ca 1.5 La 0.5 Ce 0.3 Bi 0.5 Mo 13 O x +30% SiO2

[0134] The peak elution is similar to that in Example 1, except that the first reduction peak is located at 520°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak elution is 146°C.

[0135] The evaluation method is the same as S6 in Example 1.

[0136] The reaction results are as follows: propylene conversion rate was 98.7%, and acrylonitrile yield was 82.2%.

[0137] Example 4

[0138] (1) Preparation of ammonia oxidation catalyst

[0139] S1. 620.9 grams of (NH4)6Mo7O 24 • Dissolve 4H2O in deionized water, then add 949.9 g of Fe(NO3)2O. 3)3 ·9H2O, 50.8 g La(NO3)3·6H2O and 37.2 g Sm(NO3)3·6H2O, with a solid content of 25% by mass, were mixed at 60℃ and stirred for 20 min to form solution I;

[0140] S2. Dissolve 12.4 g CsNO3, 103.4 g Bi(NO3)3·5H2O, 626.1 g Ni(NO3)2·6H2O, 135.3 g Sr(NO3)2·6H2O, 7.3 g H3PO4, and 4.31 g CrO3 in deionized water to obtain a solid content of 28% by mass. Mix at 60°C and stir for 20 min to form solution II.

[0141] S3. 362.3 grams of (NH4)6Mo7O 24 • Dissolve 4H2O in deionized water, add 2200 g of silica sol with a weight concentration of 40% and a solid content of 30% by mass, mix at 30°C, stir for 5 min to form mixture I.

[0142] S4. Add solution I to mixture I and stir. The mixing temperature is 30℃ and the stirring time is 20min to form mixture II.

[0143] S5. Add solution II to mixture II and stir at 30℃ for 30 min to form a slurry. Increase the temperature of the slurry to 150℃ at a rate of 10℃ / min and hold for 15 min. Perform microsphere forming on the prepared slurry in a spray dryer at 300℃ for 0.5 h, resulting in an average droplet diameter of 100 μm, to obtain particulate matter. Finally, calcine in air at a rate of 5℃ / min to 300℃, hold for 30 min, then increase the temperature to 550℃ at 20℃ / min and hold for 45 min. The composition of the catalyst obtained according to the above steps is shown in the following formula:

[0144] 60% P 0.15 Cs 0.15 Fe 5.46 Ni 5.0 Cr 0.1 Sr 1.5 Sm 0.5 La 0.3 Bi 0.5 Mo 13 O x +40% SiO2

[0145] The peak elution is similar to that in Example 1, except that the first reduction peak is located at 515°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak elution is 160°C.

[0146] The evaluation method is the same as S6 in Example 1.

[0147] The reaction results are as follows: propylene conversion rate was 98.0%, and acrylonitrile yield was 81.9%.

[0148] Example 5

[0149] (1) Preparation of ammonia oxidation catalyst

[0150] S1. 646.8 grams of (NH4)6Mo7O 24 Dissolve 4H2O in deionized water, then add 991.9 g of Fe(NO3)2O. 3)3 ·9H2O, 38.8 g Sm(NO3)3·6H2O and 38.7 g Ce(NO3)3·6H2O, with a solid content of 25% by mass, were mixed at 60℃ and stirred for 20 min to form solution I;

[0151] S2. Dissolve 9.85 g RbNO3, 108 g Bi(NO3)3·5H2O, 653.8 g Ni(NO3)2·6H2O, 171.2 g Mg(NO3)2·6H2O, and 2.25 g CrO3 in deionized water to obtain a solid content of 28% by mass. Mix at 60°C and stir for 20 min to form solution II.

[0152] S3. 379.9 grams of (NH4)6Mo7O 24 • Dissolve 4H2O in deionized water, add 1650 g of silica sol with a weight concentration of 40% and a solid content of 30% by mass, mix at 30°C, and stir for 5 min to form mixture I.

[0153] S4. Add solution I to mixture I and stir. The mixing temperature is 30℃ and the stirring time is 20min to form mixture II.

[0154] S5. Add solution II to mixture II and stir at 30℃ for 20 min to form a slurry. Increase the temperature of the slurry to 150℃ at a rate of 10℃ / min and hold for 15 min. Perform microsphere forming on the prepared slurry in a spray dryer at 300℃ for 0.5 h, resulting in an average droplet diameter of 100 μm, to obtain particulate matter. Finally, calcine in air at a rate of 5℃ / min to 300℃, hold for 30 min, then increase the temperature to 550℃ at 20℃ / min and hold for 45 min. The composition of the catalyst obtained according to the above steps is shown in the following formula:

[0155] 60% Cr 0.05 Rb 0.15 Fe 5.46 Ni 5.0 Mg 1.5 Sm 0.5 Ce 0.2 Bi 0.5 Mo 13 O x +40% SiO2,

[0156] The peak elution is similar to that in Example 1, except that the first reduction peak is located at 522°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak elution is 165°C.

[0157] The evaluation method is the same as S6 in Example 1.

[0158] The reaction results are as follows: propylene conversion rate was 98.4%, and acrylonitrile yield was 82.3%.

[0159] Example 6

[0160] (1) Preparation of ammonia oxidation catalyst

[0161] S1. 644.7 grams of (NH4)6Mo7O 24 Dissolve 4H2O in deionized water, then add 988.7 g of Fe(NO3)2O. 3)3 ·9H2O, 35.2 g La(NO3)3·6H2O and 95.5 g Pr(NO3)3·6H2O, with a solid content of 25% by mass, were mixed at 60℃ and stirred for 20 min to form solution I;

[0162] S2. Dissolve 6.54 g RbNO3, 107.6 g Bi(NO3)3·5H2O, 651.7 g Ni(NO3)2·6H2O, 170.6 g Mg(NO3)2·6H2O, and 7.5 g AgNO3 in deionized water to obtain a solid content of 28% by mass. Mix at 60°C and stir for 20 min to form solution II.

[0163] S3. 378.7 grams of (NH4)6Mo7O 24 • 4H2O was dissolved in deionized water, and 2750 g of silica sol with a weight concentration of 40% was added. The mixture was mixed at 30°C and stirred for 10 min. The solid content was 30% by mass, forming mixture I.

[0164] S4. Add solution I to mixture I and stir. The mixing temperature is 30℃ and the stirring time is 20min to form mixture II.

[0165] S5. Add solution II to mixture II and stir at 30℃ for 20 min to form a slurry. Increase the temperature of the slurry to 150℃ at a rate of 10℃ / min and hold for 15 min. Perform microsphere forming on the prepared slurry in a spray dryer at 300℃ for 0.5 h, resulting in an average droplet diameter of 100 μm, to obtain particulate matter. Finally, calcine in air at a rate of 5℃ / min to 300℃, hold for 30 min, then increase the temperature to 550℃ at 20℃ / min and hold for 45 min. The composition of the catalyst obtained according to the above steps is shown in the following formula:

[0166] 60% Ag 0.1 Rb 0.10 Fe 5.46 Ni 5.0 Cr 0.1 Pr 0.5 La 0.2 Bi 0.5 Mo 13 O x +40% SiO2

[0167] The peak elution is similar to that in Example 1, except that the first reduction peak is located at 530°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak elution is 170°C.

[0168] The evaluation method is the same as S6 in Example 1.

[0169] The reaction results are as follows: propylene conversion rate was 98.8%, and acrylonitrile yield was 81.9%.

[0170] Example 7

[0171] All conditions are the same as in Example 1, except that (NH4)6Mo7O is added in step S1. 24 The amount of 4H2O added in step S2 is 162.7 grams, and the amount of Mg(NO3)2·6H2O added in step S2 is 652 grams.

[0172] Following step S5 of Example 1, the peak elution is similar to that of Example 1, with the first reduction peak located at 518°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak elution is 160°C.

[0173] The evaluation method is the same as S6 in Example 1.

[0174] The reaction results are as follows: propylene conversion rate was 97.9%, and acrylonitrile yield was 81.8%.

[0175] Comparative Example 1

[0176] All conditions were the same as in Example 1, except that 814.7 grams of (NH4)6Mo7O were used. 24 • 4H2O is added entirely in step S3, while (NH4)6Mo7O is not added in step S1. 24 ·4H2O.

[0177] Following step S5 in Example 1, the peak elution is similar to that in Example 1, with the first reduction peak located at 570°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak elution is 220°C.

[0178] The evaluation method is the same as S6 in Example 1.

[0179] The reaction results are as follows: propylene conversion rate was 91.0%, and acrylonitrile yield was 70.1%.

[0180] Comparative Example 2

[0181] All conditions were the same as in Example 1, except that the amount of Ni(NO3)2·6H2O in step S2 was 0g.

[0182] Following step S5 in Example 1, the peak elution is similar to that in Example 1, with the first reduction peak located at 589°C. The temperature difference between the end of the reduction at the first reduction peak and the beginning of the peak elution is 208°C.

[0183] The evaluation method is the same as S6 in Example 1.

[0184] The reaction results are as follows: propylene conversion rate was 90.5%, and acrylonitrile yield was 70.8%.

[0185] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An ammonia oxidation catalyst, characterized in that, The catalyst has the general formula Mo. a Bi b Fe c X d Y e Z f N g O h The active components; Wherein, X is selected from at least one rare earth element; Y is selected from at least one alkali metal element; Z is selected from at least one alkaline earth metal element; and N is selected from at least one of W, V, Zr, P, Nb, Ni, Co, Cr, Mn, Ti, Au, Ag, Pt, Ru, Rh, Pd, Ti, Sb, In, Sn, and Te. The atomic ratio of b to a is 0.008-0.25; the atomic ratio of c to b is 1-12; the atomic ratio of the sum of d, e, and f to a is 0.05-0.4; the atomic ratio of g to a is 0.01-1; h is determined by the atomic ratio and valence state of elements other than oxygen. The catalyst has at least two reduction peaks in its H2-TPR spectrum; the difference between the end temperature and the start temperature of the first reduction peak in the H2-TPR spectrum of the catalyst is ≤200℃; and the highest temperature of the first reduction peak is below 560℃. Catalyst preparation methods include: S1. Mix the first part of the Mo source, Fe source and X source under solution conditions to form solution I; S2. The Z source, Bi source, Y source, and N source are mixed under solution conditions to form solution II; S3. The carrier source and the second part of the Mo source are mixed under solution conditions to form mixture I; S4. Mix solution I with mixture I to obtain mixture II; S5. Mix solution II with mixture II to obtain a slurry, heat-treat the slurry, shape it, and calcine it.

2. The ammonia oxidation catalyst according to claim 1, wherein, In the H2-TPR spectrum of the catalyst, the difference between the end temperature and the start temperature of the first reduction peak is ≤180℃; and / or The temperature of the first reduction peak is below 540℃; and / or The catalyst has a particle size of 40-60 μm; and / or The atomic ratio of b to a is 0.1-0.22; and / or The atomic ratio of c to b is 3-10; and / or The atomic ratio of the sum of d, e, and f to a is 0.20-0.35; and / or The atomic ratio of g to a is 0.5-0.

7.

3. The ammonia oxidation catalyst according to claim 2, wherein the particle size of the catalyst is 45-55 μm.

4. The ammonia oxidation catalyst according to claim 1 or 2, wherein, X is selected from at least one of La, Ce, Pr, Nd, and Sm; and / or The Y is selected from at least one of Li, Na, K, Rb, and Cs; and / or The Z is selected from at least one of Be, Mg, Ca, Sr and Ba; and / or The N is selected from at least one of W, Zr, P, Nb, Ni, Co, Cr, Ag, Mn, and In; and / or The catalyst support includes at least one of silicon oxide, zirconium oxide, cerium oxide, and titanium oxide.

5. The ammonia oxidation catalyst according to claim 4, wherein, X is at least one of La, Pr, Ce, and Nd; and / or The Y is at least one of K, Cs, and Rb; and / or Z is Mg and / or Ca; and / or The average particle size distribution of the carrier is 5-35 nm; and / or The catalyst contains 10-90% by weight of support and 10-90% by weight of active component.

6. The ammonia oxidation catalyst according to claim 1, wherein, The carrier source includes at least one of silica sol, silica aerogel, and pure silica molecular sieve; and / or The ratio of the first Mo source to the second Mo source is 1:0.5-1.5; and / or In step S1, the mixing conditions include: the solid content of solution I is 15-30% by weight; and / or Temperature is 30-80℃; and / or The time is 10-40 minutes; and / or In step S2, the mixing conditions include: Solution II has a solid content of 15-40% by weight; and / or Temperature is 30-80℃; and / or The time is 10-40 minutes; and / or In step S3, the mixing conditions include: The solid content of mixture I is 20-40% by weight; and / or Temperature is 25-50℃; and / or The time is 5-10 minutes; and / or In step S4, the mixing conditions include: Temperature is 25-40℃; and / or The time is 10-30 minutes; and / or In step S5, the mixing conditions include: Temperature is 25-40℃; and / or The time is 10-30 minutes.

7. The ammonia oxidation catalyst according to claim 6, wherein, The carrier source is silica sol, and the solid content of the silica sol is 20-50 wt%.

8. The ammonia oxidation catalyst according to claim 1, wherein, In step S5, the heat treatment conditions include: The heating rate is 8-15℃ / min; and / or Temperature is 100-150℃; and / or The time is 5-60 minutes.

9. The ammonia oxidation catalyst according to claim 1, wherein, In step S5, The molding method is spray drying, with conditions including: a temperature of 250-350℃; and / or a time of 0.1-2.0 h; and / or The spray droplet diameter is 20-200 μm; and / or The roasting conditions include: Increase the temperature to 250-400℃ at a rate of 5-20℃ / min and hold for 10-60 min. Then increase the temperature to 400-700℃ at a rate of 5-20℃ / min and hold for 20-90 min.

10. The ammonia oxidation catalyst according to claim 9, wherein, In step S5, The molding method is spray drying, with conditions including: a temperature of 300-350℃; and / or a time of 0.2-1.0 h; and / or The diameter of the spray droplets is 40-180μm.

11. The use of the ammoxidation catalyst according to any one of claims 1-10 in the ammoxidation reaction of olefins.

12. The application according to claim 11, wherein, The olefin is selected from propylene and / or isobutylene.

13. A method for producing acrylonitrile by ammoxidation of propylene, characterized in that, The method includes contacting a propylene feedstock, an oxygen source, and an ammonia source in the presence of the catalyst described in any one of claims 1-10.

14. The method according to claim 13, wherein, The conditions for contact include: The oxygen source is oxygen-containing gas; and / or The contact takes place in a fluidized bed reactor; and / or The molar ratio of propylene feedstock (based on propylene), ammonia source (based on NH3), and oxygen source (based on O2) is 1:1.1-1.35:1.8-2.5; and / or Temperature is 420-440℃; and / or The pressure is 0.03-0.14 MPa; and / or The weight hourly space velocity is 0.04-0.10 h⁻¹. -1 .

15. The method according to claim 14, wherein, The oxygen content in the oxygen source is 20-30% by volume.

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