Ammonia oxidation catalyst, preparation method and application thereof, and method for preparing acrylonitrile through propylene ammoxidation

Abstract

The invention relates to the field of catalysis, in particular to an ammoxidation catalyst, a preparation method and application thereof and a method for preparing acrylonitrile through propylene ammoxidation, and the catalyst comprises an active component with the general formula of MoaBibFecXdYeZfNgOh, the H2-TPR spectrum of the catalyst at least contains two reduction peaks; wherein the highest peak position of the first reduction peak is lower than 560 DEG C, and the difference value between the end peak appearance temperature and the start peak appearance temperature of the first reduction peak is less than or equal to 200 DEG C. The catalyst has the characteristics of high low-temperature activity and excellent stability when being used in the reaction for preparing acrylonitrile through propylene ammoxidation.

Description

Technical Field

[0001] The present invention relates to the field of catalysis, and particularly to an ammonia oxidation catalyst, a preparation method and application thereof, and a method for producing acrylonitrile by ammoxidation of propylene. Background Art

[0002] Acrylonitrile (AN) is a raw material monomer for synthesizing acrylic fiber, and is also a raw material for thermoplastic synthetic resins such as ABS and SAN, nitrile rubber, adiponitrile, acrylamide and other derivatives, and is one of the important products in petrochemical industry. The process technology for producing acrylonitrile by ammoxidation of propylene has become increasingly mature, and the development of acrylonitrile catalysts with excellent performance has been a hot topic in the acrylonitrile industry.

[0003] At present, the industrial production of olefin ammoxidation to produce unsaturated nitriles still generally adopts the fluidized bed ammoxidation process. As one of the core technologies of this process, the research and improvement of catalysts have always been emphasized. Currently, there are mainly two types of catalysts for industrial ammoxidation of propylene to acrylonitrile: Mo-Bi series and Sb series. Among them, the Mo-Bi series catalysts dominate, accounting for 95% of the olefin oxidation market. Previous research and exploration have mainly focused on Mo-Bi series catalysts. By introducing metal components with variable valence states such as Fe, Ce and other elements into the catalyst, the oxidation-reduction performance of the catalyst is improved, and the effective state of the active components of the catalyst is restored quickly; by introducing metal elements with ionic radii greater than 0.8 nm and less than 0.8 nm, such as Cr, Ni, Mg, Mn, Zn, Al and other elements, the functions of structure and electronic assistants are played to improve the structure and stability of the catalyst; by introducing rare earth elements, the amount of lattice oxygen of the catalyst is increased to improve the catalytic performance of the catalyst; by introducing elements such as Cs, Rb, P, B, Al, etc., the surface of the catalyst is modified and the acidity and alkalinity are adjusted to improve the selectivity and activity of the catalyst.

[0004] CN110557941A proposes that by controlling the composition and state of specific peaks in X-ray diffraction analysis, the catalyst has a higher ammonia conversion rate, and the yields of acrylonitrile and hydrogen cyanide as ammoxidation products of acrylonitrile are increased.

[0005] CN113692315A proposes that by controlling the composition of specific phases in X-ray analysis, while suppressing the decrease in the yield of acrylonitrile, the yield of hydrogen cyanide can be increased. However, no relevant research on the further oxidation-reduction performance of the catalyst has been carried out above. Summary of the Invention

[0006] The object of the present invention is to overcome the problems existing in the prior art, namely, high catalyst reaction temperature and poor long-term stability, and to provide an ammonia oxidation catalyst, a preparation method and application thereof, and a method for preparing acrylonitrile by ammoxidation of propylene. The catalyst has the characteristics of low activation starting temperature and uniform distribution of active components, and has high low-temperature activity and excellent stability when used in the reaction of ammoxidation, especially the ammoxidation of propylene to acrylonitrile.

[0007] To achieve the above object, on the one hand, the present invention provides an ammonia oxidation catalyst, and the catalyst has an active component with the general formula of Mo a Bi b Fe c X d Y e Z f N g O h ; wherein, X is selected from at least one of rare earth elements; Y is selected from at least one of alkali metal elements; Z is selected from at least one of alkaline earth metal elements; 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 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 H 2 -TPR spectrum of the catalyst contains at least two reduction peaks; in the H 2 -TPR spectrum of the catalyst, the difference between the peak temperature at the end and the peak temperature at the start of the first reduction peak ≤ 200 °C; the peak temperature of the highest peak of the first reduction peak is lower than 560 °C.

[0008] On the second aspect, the present invention provides a preparation method of an ammonia oxidation catalyst, and the method includes:

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

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

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

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

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

[0014] The third aspect of the present invention provides the ammoxidation catalyst described in the present invention and its application in the ammoxidation reaction of olefins.

[0015] The fourth aspect of the present invention provides a method for preparing acrylonitrile by ammoxidation of propylene, which includes: contacting a propylene raw material, an oxygen source and an ammonia source in the presence of the catalyst described in the present invention.

[0016] By the above technical solutions, the present invention has the following beneficial effects:

[0017] The ammoxidation catalyst described in the present invention has an active component with the general formula Mo a Bi b Fe c X d Y e Z f N g O h ; wherein, X is selected from at least one of rare earth elements; Y is selected from at least one of alkali metal elements; Z is selected from at least one of alkaline earth metal elements; 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 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 H 2 -TPR spectrum of the catalyst contains at least two reduction peaks; in the H 2 -TPR spectrum of the catalyst, the difference between the peak temperature at the end and the starting peak temperature of the first reduction peak ≤ 200 °C; the highest peak temperature of the first reduction peak is lower than 560 °C, and it has the characteristics of high low-temperature activity and excellent stability in the reaction of ammoxidation, especially in the preparation of acrylonitrile by ammoxidation of propylene. Description of the Drawings

[0018] Figure 1 The H 2 -TPR spectrum of the catalyst prepared in Example 1. Detailed Embodiments

[0019] In the ranges disclosed herein, the endpoints and any values are not limited to the exact 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 each range, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0020] The present invention provides an ammonia oxidation catalyst, which has an active component with the general formula Mo a Bi b Fe c X d Y e Z f N g O h ; wherein, X is selected from at least one of rare earth elements; Y is selected from at least one of alkali metal elements; Z is selected from at least one of alkaline earth metal elements; 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 sum of d, e and f and the atomic ratio of 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 H 2 -TPR spectrum of the catalyst contains at least two reduction peaks; in the H 2 -TPR spectrum of the catalyst, the difference between the ending peak temperature and the starting peak temperature of the first reduction peak ≤ 200 °C; the highest peak temperature of the first reduction peak is lower than 560 °C.

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

[0022] According to a particularly preferred embodiment of the present invention, in the H 2 -TPR spectrum of the ammonia oxidation catalyst, the difference between the ending peak temperature and the starting peak temperature of the first reduction peak ≤ 180 °C. In the present invention, the ending peak position of the first reduction peak is the starting peak position of the second reduction peak. Thus, the H 2 -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 ending peak temperature of the first reduction peak of the ammonia oxidation catalyst is lower than 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 fluidity of the catalyst in the reactor, especially in the 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 foregoing 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, 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, 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 carrier of the catalyst comprises at least one of silica, zirconia, ceria, and titania.

[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, based on the total weight of the catalyst, the catalyst contains 10-90% by weight of the carrier and 10-90% by weight of the active component.

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

[0038] The catalysts having the foregoing characteristics can all be used in the present invention, and there is no special requirement for their preparation methods. For the present invention, a preparation method of an ammonia oxidation catalyst is provided, and this preparation method includes:

[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. Mix the carrier source and the second part of the Mo source under solution conditions to form Mixture I;

[0042] S4. Mix Solution I and Mixture I to obtain Mixture II;

[0043] S5. Mix Solution II and Mixture II to obtain a slurry, and heat-treat, shape and calcine the slurry. In the present invention, there is no special requirement for the active component source, as long as the object of the present invention can be achieved, it can be carried out with reference to the prior art. The Mo source, Bi source, Fe source, X source, Y source, Z source and N source are each selected from the corresponding metal compounds, preferably the corresponding metal salts.

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

[0045] In the present invention, the carrier source in step S3 can be a conventional selection in the art. Taking silica as the carrier 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 the solid content of silica sol is 20-50 wt%.

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

[0047] In the present invention, there is no special requirement 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 the present invention, the mixing conditions in S1 can be a conventional selection in the art. The following is a demonstration, but does not limit the scope of the present 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 foregoing preferred embodiment, the stability of the active phase can be further improved.

[0054] In the present invention, the mixing conditions in S2 can be a conventional choice in the art. The following is a demonstration, but it does not limit the scope of the present invention.

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

[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 foregoing preferred embodiment, the stability performance of the corresponding active phase can be further improved.

[0059] In the present invention, the mixing conditions in S3 can be a conventional choice in the art. The following is a demonstration, but it does not limit the scope of the present invention.

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

[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 S3 is 5 - 10 min.

[0063] By adopting the foregoing preferred embodiment, the dispersion of the active component on the carrier can be further improved.

[0064] In the present invention, the mixing conditions in S4 can be a conventional choice in the art. The following is a demonstration, but it does not limit the scope of the present invention.

[0065] According to a preferred embodiment of the present invention, the mixing temperature in 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 foregoing preferred embodiments, the uniform distribution of different active phases can be further improved, which is conducive to the formation of solid solutions.

[0068] In the present invention, the mixing conditions in S5 can be a conventional choice in the art, and the following is a demonstration, but it does not limit the scope of the present invention thereby.

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

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

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

[0072] In the present invention, the heat treatment conditions of the slurry in step S5 can be a conventional choice in the art, and the following is a demonstration, but it does not limit the scope of the present invention thereby.

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

[0076] In the present invention, there are no special requirements for the conditions of drying and roasting, and it can be carried out with reference to the prior art. The following is a demonstration, but it does not limit the scope of the present invention thereby.

[0077] According to a preferred embodiment of the present invention, both drying and roasting are carried out in an oxygen-containing gas. The following is a demonstration, but it does not limit the scope of the present invention thereby.

[0078] In the present invention, there are no special requirements for the molding method, and it can be carried out with reference to the prior art. The following is a demonstration, but it does not limit the scope of the present invention thereby. According to a preferred embodiment of the present invention, the molding method is spray drying.

[0079] In the present invention, the molding conditions can be a conventional choice in the art, and the following is a demonstration, but it does not limit the scope of the present invention thereby.

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

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

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

[0083] In the present invention, the conditions of roasting can be a conventional choice in the art. The following is a demonstration, but it does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the conditions of roasting are as follows: heating up to 250 - 400 °C at a heating rate of 5 - 20 °C / min and holding for 10 - 60 min, then heating up to 400 - 700 °C at a heating rate of 5 - 20 °C / min and holding for 20 - 90 min.

[0084] The present invention provides an ammoxidation catalyst prepared by the preparation method described in the present invention.

[0085] The present invention provides the application of the ammoxidation catalyst described in the present invention in the ammoxidation reaction of olefins. According to a preferred embodiment of the present invention, the olefin is selected from propylene and / or isobutene.

[0086] The present invention provides a method for preparing acrylonitrile by ammoxidation of propylene, which includes: contacting a propylene raw material, an oxygen source and an ammonia source in the presence of the catalyst described in the present invention.

[0087] In the present invention, in the preparation of acrylonitrile by ammoxidation of propylene, the contacting conditions can be a conventional choice in the art.

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

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

[0090] According to a preferred embodiment of the present invention, in the contacting conditions, the molar ratio of the propylene raw material based on propylene, the ammonia source based on NH 3 calculated, and the oxygen source based on O 2 calculated is 1∶(1.1 - 1.35)∶(1.8 - 2.5).

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

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

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

[0094] In the present invention, in the operation of ammoxidation of propylene to produce acrylonitrile with the catalyst, the catalyst loading amount is determined according to actual operation needs without special requirements.

[0095] In the present invention, the catalyst composition is based on the composition calculated from the feedstock.

[0096] In the present invention, the particle size is measured using a Malvern MS2000 laser particle size analyzer:

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

[0098] Before sample determination, the refractive index of the catalyst needs to be selected. The refractive index of SiO 2 with a refractive index of 1.45 is used as the refractive index for measuring the sample;

[0099] Before sample measurement, the background needs to be measured. After measurement, the sample is added to 10% of the light obscuration, and the average value is selected after three measurements.

[0100] In the present invention, H 2 -TPR (H 2 -TPR spectrum, H 2 -temperature programmed reduction) is carried out using an AutoChemII 2920 from Micromeritics Instrument Corporation of the United States. The carrier gas composition is 5% H 2 + 95% Ar, the carrier gas flow rate is 20 mL / min, and the sample dosage is 0.05 g; at 673 K, the sample is purged with Ar gas for 1 h, cooled to 323 K, and then heated to 923 K at a heating rate of 10 K·min -1 . The reduction performance of the sample is detected by a TCD detector.

[0101] The calculation method of propylene conversion rate is as follows:

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

[0103] Acrylonitrile yield = carbon mole number of generated acrylonitrile / total carbon mole number of each component × 100%.

[0104] Example 1

[0105] S1. 419.2 grams of (NH 4 ) 6 Mo 7 O 24 ·4H 2O is dissolved in deionized water, and 642.7 g of Fe(NO 3 ) 3 ·9H 2 O, 76 g of Pr(NO 3 ) 3 ·6H 2 O are added. The solid content is 25% by mass, the mixing temperature is 60 °C, and it is stirred for 20 min to form Solution I;

[0106] S2. 3.59 g of KOH, 171.3 g of Bi(NO 3 ) 3 ·5H 2 O, 518.7 g of Ni(NO 3 ) 2 ·6H 2 O, 135.8 g of Mg(NO 3 ) 2 ·6H 2 O are dissolved in deionized water. The solid content is 27% by mass, the mixing temperature is 60 °C, and it is stirred for 20 min to form Solution II;

[0107] S3. 395.5 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O is dissolved in deionized water, 2750 g of silica sol with a weight concentration of 40% is added, the mixing temperature is 30 °C, and it is stirred for 5 min. The solid content is 30% by mass to form Mixed Solution I;

[0108] S4. Solution I is added to Mixed Solution I and then stirred. The mixing temperature is 30 °C, and the stirring time is 20 min to form Mixed Solution II;

[0109] S5. Solution II is added to Mixed Solution II and stirred. The mixing temperature is 30 °C, and the stirring time is 20 min to form a slurry. The slurry is heated to 150 °C at a heating rate of 10 °C / min and kept at a constant temperature for 15 min. The prepared slurry is subjected to microsphere granulation in a spray dryer. The drying temperature is 300 °C, the drying time is 0.5 h, and the average diameter of the spray liquid droplets is 100 μm to obtain particulate matter. Finally, it is calcined in an air atmosphere. The calcination heating rate is controlled at 5 °C / min to 300 °C, held for 30 min, and then heated to 550 °C at 20 °C / min and held for 45 min. The composition of the catalyst obtained according to the above steps is represented by the following formula:

[0110] 50% K 0.15 Fe 4.46 Ni 5.0 Mg 1.5 Pr 0.5 La1.0 Bi 1.0 Mo 13 O x +50% SiO 2

[0111] H 2 - The results measured by the TPR spectrum are as Figure 1 shown, where the position of the first reduction peak is 525 °C. The temperature difference between the end position and the start peak position of the first reduction peak is 145 °C.

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

[0113] On a millimeter fluidized bed reactor, the catalyst particle size is 100 microns, the reaction temperature: 430 °C; the reaction pressure: 0.084 MPa; the catalyst loading: 300 g; the catalyst propylene load (WWH, weight hourly space velocity): 0.085 h -1 ; The raw material ratio (molar): C 3 = / NH 3 / air = 1 / 1.25 / 2.0. After running for 500 hours.

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

[0115] Example 2

[0116] (1) Preparation of the ammoxidation catalyst

[0117] S1. Dissolve 451.3 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, add 692 g of Fe(NO 3)3 ·9H 2 O, 45.3 g of La(NO 3 ) 3 ·6H 2 O and 82.6 g of Nd(NO 3 ) 3 ·6H 2 O, the solid content is 20% by mass, the mixing temperature is 80 °C, stir for 10 min to form solution I;

[0118] S2. Add 3.86 g of KOH, 92.2 g of Bi(NO 3 ) 3 ·5H 2 O, 442.6 g of Co(NO 3 ) 2·6H 2 O, 146.2 g of Mg(NO 3 ) 2 ·6H 2 O, 3.84 g of CrO 3 , 134.7 g of Mn(NO 3 ) 2 Dissolve in deionized water, with a solid content of 25% by mass, a mixing temperature of 80 °C, and stir for 10 min to form Solution II.

[0119] S3. Dissolve 425.7 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, add 2750 g of silica sol with a weight concentration of 40%, stir for 30 min, then the solid content is 30% by mass, the mixing temperature is 30 °C, stir for 5 min, and stir to form Mixture I.

[0120] S4. Add Solution I to Mixture I and stir, with a mixing temperature of 40 °C and a stirring time of 30 min to form Mixture II;

[0121] S5. Add Solution II to Mixture II and stir, with a mixing temperature of 40 °C and a mixing time of 10 min to form a slurry. Heat the slurry to 150 °C at a heating rate of 15 °C / min and keep it at a constant temperature for 10 min. Perform microsphere granulation on the prepared slurry in a spray dryer, with a drying temperature of 300 °C, a drying time of 0.5 h, and an average spray droplet diameter of 100 μm to obtain particulate matter. Finally, calcine in an air atmosphere, control the calcination heating rate to 10 °C / min to 300 °C, hold for 20 min, and then rise to 550 °C at 10 °C / min and hold for 60 min. The composition of the catalyst obtained according to the above steps is represented by the following formula:

[0122] 50% Cr 0.1 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% SiO 2

[0123] The peak appearance is similar to that in Example 1, where the position of the first reduction peak is 530 °C. The temperature difference between the end position of the first reduction peak and the start position of the peak appearance is 150 °C.

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

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

[0126] Example 3

[0127] (1) Preparation of ammoxidation catalyst

[0128] S1. Dissolve 565.1 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, add 866.6 g of Fe(NO 3)3 ·9H 2 O, 105.4 g of La(NO 3 ) 3 ·6H 2 O and 69.2 g of Ce(NO 3 ) 3 ·6H 2 O. The solid content is 20% by mass, the mixing temperature is 40 °C, and stir for 30 min to form Solution I;

[0129] S2. Dissolve 11.74 g of RbNO 3 , 128.7 g of Bi(NO 3 ) 3 ·5H 2 O, 772.5 g of Co(NO 3 ) 2 ·6H 2 O, 188 g of Ca(NO 3 ) 2 ·6H 2 O, 6.54 g of ZrO 2 , 5.36 g of CrO 3 in deionized water. The solid content is 25% by mass, the mixing temperature is 40 °C, and stir for 30 min to form Solution II;

[0130] S3. Dissolve 659.3 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, add 1650 g of silica sol with a weight concentration of 40%. The mixing temperature is 30 °C. After stirring for 10 min, the solid content is 35% by mass to form Mixed Solution I.

[0131] S4. Add Solution I to Mixed Solution I and stir. The mixing temperature is 40 °C and the stirring time is 30 min to form Mixed Solution II.

[0132] S5. Add solution II to the mixed solution II and stir. The mixing temperature is 40 °C and the stirring time is 30 min to form a slurry. Heat the slurry to 150 °C at a heating rate of 10 °C / min and keep it at a constant temperature for 15 min. Perform microsphere granulation on the prepared slurry in a spray dryer. The drying temperature is 300 °C, the drying time is 0.5 h, and the average diameter of the spray droplets is 100 μm to obtain particulate matter. Finally, calcine it in an air atmosphere. Control the calcination heating rate to 300 °C at 20 °C / min, hold for 60 min, and then rise to 550 °C at 20 °C / min and hold for 30 min. The composition of the catalyst obtained according to the above steps is represented 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% SiO 2

[0134] The peak appearance is similar to that in Example 1, where the position of the first reduction peak is 520 °C. The temperature difference between the end position of the first reduction peak and the start position of the peak appearance is 146 °C.

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

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

[0137] Example 4

[0138] (1) Preparation of the ammoxidation catalyst

[0139] S1. Dissolve 620.9 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, and add 949.9 g of Fe(NO 3)3 ·9H 2 O, 50.8 g of La(NO 3 ) 3 ·6H 2 O and 37.2 g of Sm(NO 3 ) 3 ·6H 2O, with a solid content of 25% by mass, a mixing temperature of 60 °C, and stirred for 20 min to form Solution I;

[0140] S2. Dissolve 12.4 g of CsNO 3 , 103.4 g of Bi(NO 3 ) 3 ·5H 2 O, 626.1 g of Ni(NO 3 ) 2 ·6H 2 O, 135.3 g of Sr(NO 3 ) 2 ·6H 2 O, 7.3 g of H 3 PO 4 , 4.31 g of CrO 3 in deionized water, with a solid content of 28% by mass, a mixing temperature of 60 °C, and stirred for 20 min to form Solution II.

[0141] S3. Dissolve 362.3 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, add 2200 g of silica sol with a weight concentration of 40%, with a solid content of 30% by mass, a mixing temperature of 30 °C, and stirred for 5 min to form Mixture I.

[0142] S4. Add Solution I to Mixture I and stir, with a mixing temperature of 30 °C and a stirring time of 20 min to form Mixture II.

[0143] S5. Add Solution II to Mixture II and stir, with a mixing temperature of 30 °C and a stirring time of 30 min to form a slurry. Heat the slurry to 150 °C at a heating rate of 10 °C / min and keep it at a constant temperature for 15 min. Form microspheres of the prepared slurry in a spray dryer, with a drying temperature of 300 °C, a drying time of 0.5 h, and an average diameter of the spray droplets of 100 μm to obtain particulate matter. Finally, calcine in an air atmosphere, control the calcination heating rate at 5 °C / min to 300 °C, hold for 30 min, and then rise to 550 °C at 20 °C / min and hold for 45 min. The composition of the catalyst obtained according to the above steps is represented by 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 Bi0.5 Mo 13 O x +40% SiO 2

[0145] The peak emergence is similar to that of Example 1, where the position of the first reduction peak is 515 °C. The temperature difference between the end position of the reduction of the first reduction peak and the start position of peak emergence is 160 °C.

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

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

[0148] Example 5

[0149] (1) Preparation of ammoxidation catalyst

[0150] S1. Dissolve 646.8 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, add 991.9 g of Fe(NO 3)3 ·9H 2 O, 38.8 g of Sm(NO 3 ) 3 ·6H 2 O and 38.7 g of Ce(NO 3 ) 3 ·6H 2 O, with a solid content of 25% by mass, a mixing temperature of 60 °C, and stir for 20 min to form Solution I;

[0151] S2. Dissolve 9.85 g of RbNO 3 , 108 g of Bi(NO 3 ) 3 ·5H 2 O, 653.8 g of Ni(NO 3 ) 2 ·6H 2 O, 171.2 g of Mg(NO 3 ) 2 ·6H 2 O, 2.25 g of CrO 3 in deionized water, with a solid content of 28% by mass, a mixing temperature of 60 °C, and stir for 20 min to form Solution II.

[0152] S3. Take 379.9 g of (NH 4 ) 6 Mo 7 O 24 ·4H2 O was dissolved in deionized water, 1650 g of silica sol with a weight concentration of 40% was added, the solid content was 30% by mass, the mixing temperature was 30°C, and stirred for 5 minutes to form a mixed solution I.

[0153] S4. Add solution I to mixed solution I and stir at a mixing temperature of 30°C for 20 minutes to form mixed solution II.

[0154] S5. Add solution II to mixed solution II and stir at a mixing temperature of 30°C for 20 minutes to form a slurry. The slurry is heated to 150°C at a rate of 10°C / min and kept at a constant temperature for 15 minutes. The prepared slurry is molded into microspheres in a spray dryer at a drying temperature of 300°C for 0.5 hours and an average diameter of the spray droplets of 100μm to obtain particles. Finally, it is calcined in an air atmosphere, and the calcination heating rate is controlled at 5°C / min to 300°C, and stays for 30 minutes, then raised to 550°C at 20°C / min and stays for 45 minutes. The composition of the catalyst obtained according to the above steps is expressed as follows:

[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%SiO 2 ,

[0156] The peaks are similar to those in Example 1, where the first reduction peak is at 522°C. The temperature difference between the end position of the first reduction peak and the start position is 165°C.

[0157] The evaluation method is consistent with S6 in Example 1.

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

[0159] Example 6

[0160] (1) Preparation of ammonia oxidation catalyst

[0161] S1. 644.7 g (NH 4 ) 6 Mo 7 O 24 ·4H 2 O was dissolved in deionized water and 988.7 g of Fe(NO 3)3 ·9H 2 ​​​​​​O, 35.2 g of La(NO 3 ) 3 ·6H 2 O and 95.5 g of Pr(NO 3 ) 3 ·6H 2 O, with a solid content of 25% by mass, a mixing temperature of 60 °C, and stirred for 20 min to form Solution I;

[0162] S2. Dissolve 6.54 g of RbNO 3 , 107.6 g of Bi(NO 3 ) 3 ·5H 2 O, 651.7 g of Ni(NO 3 ) 2 ·6H 2 O, 170.6 g of Mg(NO 3 ) 2 ·6H 2 O, 7.5 g of AgNO 3 in deionized water, with a solid content of 28% by mass, a mixing temperature of 60 °C, and stirred for 20 min to form Solution II.

[0163] S3. Dissolve 378.7 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O in deionized water, add 2750 g of silica sol with a weight concentration of 40%, with a mixing temperature of 30 °C, stirred for 10 min, and then with a solid content of 30% by mass to form Mixture I.

[0164] S4. Add Solution I to Mixture I and stir, with a mixing temperature of 30 °C and a stirring time of 20 min to form Mixture II.

[0165] S5. Add Solution II to Mixture II and stir, with a mixing temperature of 30 °C and a stirring time of 20 min to form a slurry. Heat the slurry to 150 °C at a heating rate of 10 °C / min and hold for 15 min. Form microspheres of the prepared slurry in a spray dryer, with a drying temperature of 300 °C, a drying time of 0.5 h, and an average spray droplet diameter of 100 μm to obtain particulate matter. Finally, calcine in an air atmosphere, control the calcination heating rate at 5 °C / min to 300 °C, hold for 30 min, then rise to 550 °C at 20 °C / min and hold for 45 min. The composition of the catalyst obtained according to the above steps is represented by the following formula:

[0166] 60% Ag 0.1 Rb 0.10 Fe 5.46 Ni5.0 Cr 0.1 Pr 0.5 La 0.2 Bi 0.5 Mo 13 O x +40%SiO 2

[0167] The peak appearance is similar to that in Example 1, where the position of the first reduction peak is 530 °C. The temperature difference between the end position of the reduction of the first reduction peak and the start position of the peak appearance is 170 °C.

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

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

[0170] Example 7

[0171] All conditions are the same as those in Example 1, except that the amount of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O added in step S1 is 162.7 g, and the amount of Mg(NO 3 ) 2 ·6H 2 O added in step S2 is 652 g;

[0172] Obtained according to step S5 of Example 1, the peak appearance is similar to that in Example 1, where the position of the first reduction peak is 518 °C. The temperature difference between the end position of the reduction of the first reduction peak and the start position of the peak appearance is 160 °C.

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

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

[0175] Comparative Example 1

[0176] All conditions are the same as those in Example 1, except that 814.7 g of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O is added entirely in step S3, and no (NH 4 ) 6 Mo 7 O 24 ·4H 2 O is added in step S1.

[0177] As obtained in step S5 of Example 1, the peak emergence is similar to that of Example 1, where the position of the first reduction peak is 570 °C. The temperature difference between the end position of the reduction of the first reduction peak and the start position of peak emergence is 220 °C.

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

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

[0180] Comparative Example 2

[0181] All conditions are the same as those in Example 1, except that: in step S2, the amount of Ni(NO 3 ) 2 ·6H 2 O is 0 g,

[0182] As obtained in step S5 of Example 1, the peak emergence is similar to that of Example 1, where the position of the first reduction peak is 589 °C. The temperature difference between the end position of the reduction of the first reduction peak and the start position of peak emergence is 208 °C.

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

[0184] The reaction results are as follows: the conversion rate of propylene is 90.5%, and the yield of acrylonitrile is 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 technical concept scope of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall 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 ingredient; in, X is selected from at least one of rare earth elements; Y is selected from at least one of alkali metal elements; Z is selected from at least one of alkaline earth metal elements; N is at least one selected from 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 of the 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 peak temperature and the start peak temperature of the first reduction peak is ≤200°C; The highest peak temperature of the first reduction peak is lower than 560°C.

2. The ammonia oxidation catalyst according to claim 1, wherein In the H2-TPR spectrum of the catalyst, the difference between the end peak temperature and the start peak temperature of the first reduction peak is ≤180°C; and / or The highest peak temperature of the first reduction peak is lower than 540°C; and / or The particle size of the catalyst is 40-60 μm, preferably 45-55 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 1 or 2, wherein The X is selected from at least one of La, Ce, Pr, Nd and Sm, preferably at least one of La, Pr, Ce and Nd; and / or The Y is selected from at least one of Li, Na, K, Rb and Cs, preferably at least one of K, Cs and Rb; and / or The Z is selected from at least one of Be, Mg, Ca, Sr and Ba, preferably Mg and / or Ca; 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 carrier comprises at least one of silicon oxide, zirconium oxide, cerium oxide and titanium oxide; Preferably, the average particle size distribution of the carrier is 5-35 nm; and / or Preferably, the catalyst contains 10-90% by weight of carrier and 10-90% by weight of active component.

4. A method for preparing an ammonia oxidation catalyst according to any one of claims 1 to 3, characterized in that: The method includes: S1. Mix the first part of Mo source, Fe source and X source under solution conditions to form a solution I； S2. Mixing the Z source, Bi source, Y source, and N source under solution conditions to form solution II; S3. The carrier source and the second portion of the Mo source are mixed under solution conditions to form a mixed solution I; S4. mixing solution I with mixed solution I to obtain mixed solution II; S5. Mix solution II and mixed solution II to obtain slurry, and heat-treat, shape, and calcine the slurry.

5. The preparation method according to claim 4, wherein The carrier source comprises at least one of silica sol, silica aerogel and pure silicon molecular sieve, preferably silica sol, more preferably the solid content of silica sol is 20-50wt%; and / or The usage ratio of the first part of Mo source to the second part of 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 wt %; and / or Temperature of 30-80°C; and / or The time is 10-40 minutes; and / or In step S2, the mixing conditions include: The solid content of solution II is 15-40 wt %; and / or Temperature of 30-80°C; and / or The time is 10-40 minutes; and / or In step S3, the mixing conditions include: The solid content of the mixed solution I is 20-40 wt %; and / or Temperature of 25-50°C; and / or Time is 5-10 minutes; and / or In step S4, the mixing conditions include: Temperature of 25-40°C; and / or The time is 10-30 minutes; and / or In step S5, the mixing conditions include: Temperature of 25-40°C; and / or The time is 10-30 minutes.

6. The preparation method according to claim 4 or 5, wherein: In step S5, the heat treatment conditions include: The heating rate is 8-15°C / min; and / or A temperature of 100-150°C; and / or The time is 5-60 minutes.

7. The preparation method according to claim 4 or 5, wherein: In step S5, The molding method is spray drying, and the conditions include: The temperature is 250-350°C, preferably 300-350°C; and / or The time is 0.1-2.0h, preferably 0.2-1.0h; and / or The spray droplet diameter is 20-200 μm, preferably 40-180 μm; and / or The conditions for the calcination include: The temperature is increased to 250-400°C at a heating rate of 5-20°C / min and maintained for 10-60min, and then increased to 400-700°C at a heating rate of 5-20°C / min and maintained for 20-90min.

8. Use of the ammoxidation catalyst according to any one of claims 1 to 3 in an ammoxidation reaction of olefins; preferably, the olefin is selected from propylene and / or isobutylene.

9. A method for preparing acrylonitrile by ammoxidation of propylene, characterized in that: The method comprises: contacting a propylene raw material, an oxygen source and an ammonia source in the presence of the catalyst described in any one of claims 1 to 3.

10. The method according to claim 9, wherein: The contact conditions include: The oxygen source is an oxygen-containing gas, preferably the oxygen source has an oxygen volume content of 20-30%; and / or The contacting is carried out in a fluidized bed reactor; and / or The molar ratio of the propylene raw material as propylene, the ammonia source as NH3 and the oxygen source as O2 is 1:(1.1-1.35):(1.8-2.5); and / or A temperature of 420-440°C; and / or The pressure is 0.03-0.14MPa; and / or Weight hourly space velocity is 0.04-0.10h -1 .

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