An acrylonitrile catalyst, a preparation method and application thereof

Abstract

The present application provides an acrylonitrile catalyst and its preparation method and application. The acrylonitrile catalyst comprises a carrier and an active component; the chemical formula of the active component is: A 0.01～5 B 1～ 10 C 0.01～5 Fe 0.1～15 Bi 0.01～5 Mo 22 O x A comprises at least one of Li, Na, K, Rb, and Cs; B is selected from at least one of Ca, Ba, Mn, Co, Ni, Mg, Cr, W, P, and Nb; C is selected from at least one of Ce, Pr, Nd, La, and Sm; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst. The present application adds elements such as Ce, Pr, Nd, La, and Sm, and adjusts the molar ratios of molybdenum, bismuth, and other elements. The elements cooperate with each other and work together to not only enhance the redox performance of the catalyst, but also improve the structure of the catalyst, increasing its stability. More importantly, the surface of the catalyst can be modified and its active sites adjusted, thereby improving the selectivity of acrylonitrile and further increasing the yield of acrylonitrile.

Description

Technical Field

[0001] The present application relates to the field of catalyst technology, and in particular to an acrylonitrile catalyst and a preparation method and application thereof. Background Art

[0002] Currently, the industrial production of unsaturated nitriles by olefin ammoxidation still generally relies on the fluidized bed ammoxidation process. Catalysts are a core technology, and therefore crucial. Currently, two main types of catalysts are used in the industrial ammoxidation of propylene to acrylonitrile: Mo-Bi and Sb. Mo-Bi catalysts are the mainstream, with a market share exceeding 90%, and the majority of research efforts focus on Mo-Bi catalysts.

[0003] Patents CN1210033A and CN1285238A have low yields, CN1294942A has low selectivity and yield, and the Mo-Bi catalyst proposed in CN1751790A is suitable for use under conditions of relatively high reaction pressure and high propylene load. However, the yield of acrylonitrile is not high, and the selectivity is only about 80%, which still cannot meet the requirements of high pressure, high yield, and high selectivity at the same time.

[0004] Therefore, there is an urgent need to develop a catalyst that can not only be used under high reaction pressure and high propylene load conditions, but also ensure that the catalyst has a high acrylonitrile yield and high selectivity to improve production efficiency. Summary of the Invention

[0005] In response to the above-mentioned problems, the present application provides an acrylonitrile catalyst, its preparation method, and application. By adding elements such as Ce, Pr, Nd, La, and Sm, and adjusting the molar ratio between the different elements, the various metal compounds promote each other, cooperate synergistically, change their crystal structure, and increase the amount of lattice oxygen. This not only enhances the oxidation-reduction performance of the catalyst, but also improves the structure of the catalyst and improves its stability. More importantly, the surface of the catalyst can be modified and the number and distribution of its active sites can be adjusted to generate more oxygen vacancies, increase the active sites of the catalyst, thereby improving the selectivity of acrylonitrile and further improving the yield of acrylonitrile, overcoming the shortcomings and defects mentioned in the background art.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] The invention of this application is to provide an acrylonitrile catalyst, comprising a carrier and an active component; the chemical formula of the active component is: 0.01～5 B 1～10 C 0.01～5 Fe 0.1～15 Bi 0.01～5 Mo 22 Ox ; A includes at least one of Li, Na, K, Rb, and Cs; B is selected from at least one of Ca, Ba, Mn, Co, Ni, Mg, Cr, W, P, and Nb; C is selected from at least one of Ce, Pr, Nd, La, and Sm; x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

[0008] Optionally, A includes at least two of Li, Na, K, Rb, and Cs, preferably K and Rb.

[0009] Optionally, B is selected from at least two of Ca, Ba, Mn, Co, Ni, Mg, Cr, W, P and Nb; preferably Ni, Cr, Mg and Mn.

[0010] Optionally, C is selected from at least three of Ce, Pr, Nd, La and Sm; preferably five of Ce, Pr, La, Sm and Nd.

[0011] Optionally, the active components include, by mole, 22 parts of molybdenum, 0.01 to 5 parts of bismuth, 0.1 to 15 parts of iron, 0.1 to 5 parts of cerium, 0.3 to 6 parts of praseodymium, 0.1 to 1 part of lanthanum, 0.1 to 1 part of samarium, 0.5 to 1 part of rubidium, 1 to 5 parts of manganese, 0.1 to 3 parts of nickel, 0.1 to 1 part of chromium and 0.8 part of magnesium.

[0012] The proportion of rubidium is preferably 0.6 to 0.8; the proportion of manganese is preferably 1 to 2; the proportion of cerium is preferably 0.1 to 1, more preferably 0.1 to 0.5; the proportion of nickel is preferably 0.1 to 0.3; and the proportion of praseodymium is preferably 0.3 to 0.6.

[0013] Optionally, the general chemical formula of the active component is:

[0014] A 0.1～5 Mn 1～3 Ni 0.1～3 Cr 0.3～0.7 Mg 0.8 Ce 0.1～5 Pr 0.3～6 Nd 0.1～0.5 Sm 0.3～0.8 La 0.3～0.8 Fe 0.1～ 1Bi 0.01～5 Mo 22 O x ; A includes at least one of Li, Na, K, Rb, and Cs; x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

[0015] Optionally, the general chemical formula of the active component is:

[0016] A 0.1～5 Mn1～3 Ni 0.1～3 Cr 0.3～0.7 Mg 0.8 Ce 0.1～5 Pr 0.3～6 Nd 0.1～0.5 Sm 0.3～0.8 La 0.3～0.8 Fe 0.1～ 1Bi 0.01～5 Mo 22 O x A includes at least one of Li, Na, K, Rb, and Cs; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

[0017] Optionally, the carrier accounts for 5 to 50% by mass of the acrylonitrile catalyst, preferably 30 to 50%.

[0018] At this carrier content, the carrier can cooperate better with the active components, so that the active components are mostly located on the surface of the carrier, avoiding entering the interior of the carrier, causing problems such as a decrease in catalyst performance, the occurrence of side reactions, and a decrease in yield.

[0019] The carrier can be silica sol commonly available on the market, including silicon dioxide, white carbon black, pure silicon molecular sieve, etc.

[0020] Another invention of the present application is to provide a method for preparing any of the above-mentioned acrylonitrile catalysts.

[0021] Optionally, the method comprises: (1) dissolving source A, source B, source C, Fe source and Bi source to obtain a mixed solution I; dissolving a molybdenum source and adding the carrier to obtain a mixed solution II; (2) mixing the mixed solution I and the mixed solution II under acidic or neutral conditions to obtain a slurry; and (3) granulating the slurry and then calcining it to obtain an acrylonitrile catalyst.

[0022] The A source, B source, C source, Fe source, Bi source and molybdenum source include A, B, C, Fe, Bi and molybdenum in the form of oxides, salts, bases or acids.

[0023] The salt is a soluble salt, preferably a nitrate, sulfate, carbonate, sulfite, phosphate, phosphite, or the like.

[0024] The molybdenum source is preferably molybdate or molybdenum trioxide, and more preferably ammonium molybdate.

[0025] The preferred form of carrier is silica sol.

[0026] Optionally, in step (2), stirring and mixing are performed.

[0027] The mixing conditions are: pH 1 to 7, preferably 2 to 5; temperature 40 to 100°C, preferably 60 to 90°C.

[0028] Under acidic conditions, precipitation of various substances can be avoided. When the temperature is slightly higher than room temperature, the fluidity of various substances can be increased and the mixing can be more uniform. Compared with room temperature, the various substances in this application can fuse with each other, so that they can cooperate with each other in the subsequent sintering process, change the structure and surface properties of the catalyst, and improve the catalytic performance of the catalyst.

[0029] The slurry is then granulated, preferably spray-dried, to form microspheres.

[0030] The microspheres are calcined in a calcining furnace to obtain a catalyst.

[0031] Optionally, the calcination conditions are: temperature of 500-750° C., preferably 550-700° C.; time of 1-6 h, preferably 2-6 h.

[0032] Another invention of the present application is to provide a method for preparing acrylonitrile from propylene, wherein propylene is subjected to ammoxidation in the presence of a catalyst to prepare acrylonitrile; the catalyst comprises any of the acrylonitrile catalysts described above.

[0033] That is, after ammonia, air and propylene are mixed, they react under the catalytic action of a catalyst to produce acrylonitrile.

[0034] Optionally, the molar ratio of propylene, ammonia, and air is: 1:(1.05-1.25):(9.1-9.8); the reaction temperature is 400-460°C; the reaction pressure is 0.06-0.14 MPa; and the propylene load WWH of the catalyst is 0.06-0.12 h -1 .

[0035] Compared with the prior art, this application has the following advantages:

[0036] (1) The present application prepares a new catalyst by adding Ce, Pr, La, Sm and Nd and adjusting the ratio between Mo, Ni, Mg, Cr and Fe; Ce, Pr, La, Sm and Nd can participate in the active lattice, change its crystal structure, increase the amount of lattice oxygen, thereby generating more oxygen vacancies, increasing the active sites of the catalyst, and improving the oxidation-reduction performance of the catalyst, thereby improving the catalytic performance and efficiency of the catalyst and accelerating the recovery of the effective state of the active components of the catalyst; in addition, Ce, Pr, La, Sm and Nd can also act together with other elements Ni, Mg and Fe on Mo to fix the pores and form a relatively stable structure, thereby avoiding the The structure is deformed due to aggregation, which plays a role as a structural and electronic additive, improving the structure and stability of the catalyst. Mo and Cr have the same radius. When the Cr content is too high, it will cause serious deformation of the Mo structure. Therefore, the amount of Cr added cannot be too much. The increase in Mo content and the reduction in Ni, Mg, and Fe can improve the purity of lattice oxygen and make it highly selective, thereby increasing the yield of the product and reducing the occurrence of side reactions. By introducing K and Rb, the catalyst surface is modified and the acidity and alkalinity are adjusted to improve the selectivity and activity of the catalyst. Using the acrylonitrile catalyst of the present application, the single-pass yield of acrylonitrile reaches about 85%, with the characteristics of high selectivity and good stability.

[0037] (2) The present application mixes the salt solutions of various elements at a high temperature under acidic or neutral conditions, so that the various metal compounds can be evenly mixed, which facilitates the formation of a stable structure in the subsequent sintering process, reduces the possibility of structural irregularity, and significantly improves the catalytic activity and selectivity of the formed catalyst; if there are no acidic or neutral conditions and high-temperature stirring, partial aggregation will occur, and a uniformly mixed metal compound cannot be formed, thereby affecting the overall morphology and catalytic performance of the catalyst; and this method is simple and convenient, easy to carry out industrial production, and can reduce costs and improve production efficiency. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below. However, it should be understood that the description herein is only used to explain this application and is not intended to limit the scope of this application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended solely for the purpose of describing specific embodiments and are not intended to limit this application. The reagents and instruments used herein are commercially available, and the characterization methods involved can be found in the relevant descriptions in the prior art and will not be further elaborated herein.

[0040] In order to further understand the present application, the present application is further described in detail below in conjunction with the best embodiment.

[0041] The activity of the catalyst of the present invention was evaluated in a fluidized bed reactor with an inner diameter of 38 mm. The catalyst loading was 500 g, the reaction temperature was 420°C, the molar ratio of propylene, ammonia, and air was 1:1.1:9.5, the reaction pressure was 0.08 MPa, and the reaction load was 0.08 h. -1 Run for 2000h under the conditions of

[0042] In the present invention, the definitions of propylene conversion, acrylonitrile selectivity and single-pass yield are as follows:

[0043]

[0044]

[0045]

[0046] Example 1

[0047] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0048] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0049] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0050] Example 2

[0051] (1) 74.93 g of Bi(NO3)3·5H2O, 36.45 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 26.95 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0052] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0053] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0054] Example 3

[0055] (1) 119.89 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 88.46 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain mixed solution II.

[0056] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0057] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0058] Example 4

[0059] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 74.89 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 74.18 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0060] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0061] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0062] Comparative Example 1

[0063] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH and 67.20 g of Pr(NO3)3·6H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0064] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0065] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0066] Comparative Example 2

[0067] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0068] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0069] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0070] Comparative Example 3

[0071] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 244H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0072] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0073] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0074] Comparative Example 4

[0075] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0076] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0077] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0078] Comparative Example 5

[0079] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0080] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0081] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0082] Comparative Example 6

[0083] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH, 67.20 g of Pr(NO3)3·6H2O and 185.44 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0084] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0085] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0086] Comparative Example 7

[0087] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O and 1.73 g of KOH were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0088] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0089] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0090] Comparative Example 8

[0091] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 66.89 g of La(NO3)3.6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH and 67.20 g of Pr(NO3)3·6H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0092] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0093] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0094] Comparative Example 9

[0095] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 51.96 g of Sm(NO3)3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH and 67.20 g of Pr(NO3)3·6H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0096] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0097] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0098] Comparative Example 10

[0099] (1) 74.93 g of Bi(NO3)3·5H2O, 27.34 g of RbNO3, 82.93 g of Mn(NO3)2, 40.25 g of Ce(NO3)3·6H2O, 40.63 g of Nd(NO3)3·6H2O, 17.97 g of Ni(NO3)2·6H2O, 62.41 g of Fe(NO3)3·9H2O, 63.37 g of Mg(NO3)2·6H2O, 1.73 g of KOH and 61.81 g of Cr(NO3)3·9H2O were dissolved in 160 g of water by heating to obtain solution I. 1200.0 g of (NH4)6Mo7O 24 4H2O was dissolved in 1000 g of water, and 1500 g of silica sol with a weight concentration of 40% was added to obtain a mixed solution II.

[0100] (2) Solution I and mixed solution II were mixed and stirred at a pH of 5 and a temperature of 80° C. to obtain a slurry.

[0101] (3) The prepared slurry was formed into microspheres in a spray dryer, and finally calcined in a rotary calciner at 600° C. for 4.0 hours to prepare an acrylonitrile catalyst.

[0102] Table 1

[0103]

[0104]

[0105] Comparative Example 1 lacks chromium, resulting in a lack of divalent and trivalent metal ions in the catalyst to participate in the reaction. This results in insufficient cationic vacancies, slowing the migration of lattice oxygen and reducing catalyst activity. Comparative Examples 2, 3, 4, 5, 7, 8, 9, and 10 lack rare earth elements, resulting in insufficient redox pairs in the catalyst and slowing the transfer of electrons and lattice oxygen. In Comparative Example 6, excessive chromium leads to the formation of chromium crystals and a mismatched redox pair in the catalyst.

[0106] In the examples of the present application, the Cr content is moderate, and the activity and stability of the catalyst are improved after the introduction of rare earth elements. This is mainly because rare earth elements can form a new compound containing three components with Mo and Bi, which has higher activity and selectivity. It also accelerates the redox equilibrium rate of the catalyst and maintains its structural stability even at a low oxygen partial pressure.

[0107] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. An acrylonitrile catalyst, characterized in that It includes a carrier and an active component; the general chemical formula of the active component is: A 0.01～5 Mr 1～5 Ni 0.1～3 Cr 0.1～1 Mg 0.8 Ce 0.1～5 Prof 0.3～6 Nd 0.1～0.5 Sm 0.1～1 Day 0.1～1 Feb 0.1～1 Bi 0.01～5 Mo 22 O x ; A includes at least one of Li, Na, K, Rb, and Cs; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

2. The acrylonitrile catalyst according to claim 1, characterized in that The general chemical formula of the active ingredient is: A 0.1～5 Mr 1～3 Ni 0.1～3 Cr 0.3～0.7 Mg 0.8 Ce 0.1～5 Prof 0.3～6 Nd 0.1～0.5 Sm 0.3～0.8 Day 0.3～0.8 Feb 0.1～1 Bi 0.01～ 5 Mo 22 O x ; A includes at least one of Li, Na, K, Rb, and Cs; and x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst.

3. The acrylonitrile catalyst according to claim 1, characterized in that The mass proportion of the carrier in the acrylonitrile catalyst is 5~50%.

4. The acrylonitrile catalyst according to claim 1, characterized in that The carrier accounts for 30% to 50% of the mass of the acrylonitrile catalyst.

5. A method for preparing the acrylonitrile catalyst according to any one of claims 1 to 4, characterized in that: include: (1) dissolving an A source, a Mn source, a Ni source, a Cr source, a Mg source, a Ce source, a Pr source, a Nd source, a Sm source, a La source, a Fe source, and a Bi source to obtain a mixed solution I; dissolving a molybdenum source and adding a carrier to obtain a mixed solution II; (2) Mixing the mixed solution I and the mixed solution II under acidic or neutral conditions to obtain a slurry; (3) The slurry is pelletized and then calcined to obtain an acrylonitrile catalyst.

6. The preparation method according to claim 5, characterized in that In step (2), the mixing conditions are: pH 1-7; temperature 40-100°C; In step (3), the calcination conditions are: temperature 500-750° C.; time 1-6 h.

7. The preparation method according to claim 5, characterized in that In step (2), the mixing conditions are: pH 2-5; temperature 60-90°C; In step (3), the calcination conditions are: temperature of 550-700° C.; time of 2-6 hours.

8. A method for preparing acrylonitrile from propylene, characterized in that: Propylene is subjected to ammoxidation under the action of a catalyst to prepare acrylonitrile; the catalyst comprises the acrylonitrile catalyst according to any one of claims 1 to 4.

9. The method according to claim 8, characterized in that The molar ratio of propylene, ammonia, and air is 1:(1.05-1.25):(9.1-9.8); the reaction temperature is 400-460°C; the reaction pressure is 0.06-0.14 MPa; the catalyst propylene loading WWH = 0.06-0.12 h -1 .

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