A propylene ammoxidation catalyst with high wear resistance and preparation method thereof

Abstract

The present invention provides a propylene ammoxidation catalyst with high wear resistance and a preparation method thereof, and relates to the technical field of catalysts. The preparation method comprises: preparing a Mo precursor solution, other metal solutions and a carrier solution containing sodium dodecyl sulfate; dripping the Mo precursor solution into the carrier solution in batches, and then mixing the other metal solutions to obtain a propylene ammoxidation catalyst; in the propylene ammoxidation catalyst, the stoichiometric composition of the metal oxide is M O12 Bi a Fe b A c B d C e O x ; A is Re and Zr; B is selected from at least one of Cs, Be and Ca; C is selected from at least one of Al and Co; a is 0.8-1.6, b is 2-3, c is 0.1-0.5, d is 0.1-0.3, and e is 0.3-0.9; x is a charge balance value. The propylene ammoxidation catalyst of the present invention has high catalytic activity, high stability and wear resistance, and the wear rate is significantly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a propylene ammoxidation catalyst with high abrasion resistance and a preparation method thereof. Background Art

[0002] Acrylonitrile (AN) is an important organic chemical raw material, mainly used to produce rubber, plastic acrylic, acrylamide, and synthetic fibers. Its products are widely used in textiles, clothing, automobiles, aerospace, home appliances, water treatment and other fields. At present, the main production method of acrylonitrile is the propylene ammoxidation method, which uses propylene, air and ammonia as raw materials and uses a propylene ammoxidation catalyst to catalyze the preparation of acrylonitrile. In the production process of acrylonitrile, a suitable propylene ammoxidation catalyst can improve the conversion efficiency, reduce the formation of by-products, reduce unit consumption, and reduce costs. At present, the propylene ammoxidation catalysts for producing acrylonitrile by the propylene ammoxidation method mainly include Mo (molybdenum)-Bi (bismuth) catalysts and Fe (iron)-Sb (antimony) catalysts.

[0003] Chinese invention patent CN116060028A discloses a catalyst for preparing acrylonitrile by propylene ammoxidation, and its preparation method and application; the catalyst comprises a metal oxide and a carrier component, wherein the carrier component is a silicon-based porous carrier, the metal oxide comprises at least oxides of three active metal elements, namely, Mo, Bi and Fe, and the specific surface area of ​​the catalyst is 60-100 m 2 / g, and an average pore size of 5-10nm; the preparation method of the catalyst comprises the steps of: mixing catalyst precursor particles with peroxide particles, and then calcining. The prepared acrylonitrile catalyst has high stability and still maintains good activity and selectivity after long-term operation.

[0004] US invention patent US20220023837A1 discloses a propylene ammoxidation catalyst, wherein M O12 Bi a Fe b A c B d C e O x The metal oxide represented is supported on a silica carrier, the catalyst diameter is 5-200nm and the volume is 0.1-3.0cm 3 / g, specific surface area is 50m 2 / g-1000m 2 / g:MO 12 Bi a Fe b A c B d C e O xwherein A is one or more elements selected from Ni, Mn, Co, Zn, Mg, Ca, and Ba, B is one or more elements selected from Li, Na, K, Rb, and Cs, C is one or more elements selected from Cr, W, B, Al, Ca, and V, and a to e and x are fractions of each element or element group, respectively, wherein a is 0.1-5, b is 0.1-5, c is 0.01-10, d is 0.01-2, e is 0-10, and x is 24-48.

[0005] For propylene ammoxidation catalysts, Grasselli proposed that the factors affecting the performance of the catalyst include multiple aspects: dispersion of active sites, strength of Me-O bonds, crystal structure of the catalyst, redox characteristics, interactions between different phases, multifunctionality of the catalyst and properties of surface oxygen species. Pu Fayuan et al. (Pu Fayuan, Chen Chenju, Yang Zhibin, et al. Progress in the synthesis route and catalyst research of acrylonitrile [J]. Chemical World, 2024, 65(03): 143-151.) pointed out that in order to improve the selectivity of acrylonitrile and meet the multifunctional requirements of the catalyst, it is necessary to increase the components of the catalyst.

[0006] Existing propylene ammoxidation catalysts still generally have the problems of low strength and poor wear resistance, which further affects the catalytic performance and stability of the catalyst. Therefore, it is necessary to provide a propylene ammoxidation catalyst with better strength and wear resistance, high catalytic activity and catalytic stability. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a propylene ammoxidation catalyst with high wear resistance and a preparation method thereof. Several elements of Bi, Fe, Re, Zr, Cs, Be, Ca, Al and Co are selected to be coordinated with Mo, the mixing process of the Mo precursor solution and the carrier solution is controlled, and a certain amount of sodium dodecyl sulfonate is added at the same time, so that the prepared propylene ammoxidation catalyst has a uniform pore size distribution, more active sites are exposed after the metal elements are combined with the carrier, the catalytic activity of the catalyst is improved, and the catalyst has higher stability and wear resistance.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] In one aspect, the present invention provides a method for preparing a propylene ammoxidation catalyst having high abrasion resistance, comprising the steps of:

[0010] (1) Preparing a Mo precursor solution: dissolving Mo salt in water to obtain a Mo precursor solution;

[0011] (2) Preparation of other metal solutions: dissolving compounds containing other metals in water to obtain other metal solutions;

[0012] (3) Preparation of carrier solution: sodium dodecylbenzene sulfonate and silica sol are mixed to prepare a carrier solution; in the carrier solution, the mass concentration of sodium dodecylbenzene sulfonate is 0.1-1%, and the mass solubility of SiO2 in the silica sol is 30-60%;

[0013] (4) adding 40-60% of the Mo precursor solution into the support solution at a temperature range of 35-55° C. and stirring to obtain a catalyst pretreatment solution;

[0014] (5) The catalyst pretreatment solution is mixed with other metal solutions, stirred at 40-55°C, and then the remaining amount of Mo precursor solution is added dropwise, and stirred to obtain a slurry;

[0015] (6) After the slurry is spray-dried, it is calcined at 500-700°C for 4-8h to obtain a propylene ammoxidation catalyst;

[0016] In step (2), the other metal is selected from at least one of Bi, Fe, Re, Zr, Cs, Be, Ca, Al, and Co.

[0017] Preferably, in step (1), the mass concentration of Mo salt in the Mo precursor solution is 10-20%.

[0018] Further preferably, in the Mo precursor solution, the mass concentration of Mo salt is 15%.

[0019] Preferably, in step (2), the total mass concentration of other metal compounds in the other metal solution is 20-35%.

[0020] Further preferably, in the other metal solution, the total mass concentration of other metal compounds is 25-30%.

[0021] More preferably, in the other metal solution, the total mass concentration of other metal compounds is 25%.

[0022] Preferably, in step (3), the mass concentration of sodium dodecyl sulfate in the carrier solution is 0.3-0.7%; more preferably, the mass concentration of sodium dodecyl sulfate is 0.5%.

[0023] Preferably, in step (3), the mass concentration of SiO2 in the silica sol is 35-55%; further preferably, the mass concentration of SiO2 in the silica sol is 40-50%.

[0024] Preferably, in step (3), the particle size of SiO2 in the silica sol is 10-200 nm.

[0025] Preferably, step (4) is specifically as follows: within a temperature range of 40-50° C., a 50-55% formula amount of a Mo precursor solution is added dropwise to the carrier solution at a dropping speed of 15-25 mL / min, with stirring during the dropping; after the dropping is completed, the temperature is raised to 55-60° C. and stirred for 1.5-3 h to obtain a catalyst pretreatment solution.

[0026] Further preferably, step (4) is specifically as follows: within a temperature range of 45°C, a 50% formula amount of the Mo precursor solution is added dropwise to the carrier solution at a dropping speed of 20 mL / min, with stirring during the addition; after the addition is completed, the temperature is raised to 55°C and stirred for 2 hours to obtain a catalyst pretreatment solution.

[0027] Preferably, step (5) is specifically as follows: at a temperature range of 45-50° C., the catalyst pretreatment solution is mixed with other metal solutions and stirred for 0.5-1.5 h; then the remaining amount of the Mo precursor solution is added dropwise at a rate of 15-25 mL / min while stirring; after the addition is completed, stirring is continued for 1-2 h to obtain a slurry.

[0028] Further preferably, step (5) is specifically as follows: at a temperature of 50° C., the catalyst pretreatment solution is mixed with other metal solutions and stirred for 1 hour; then the remaining amount of the Mo precursor solution is added dropwise at a dropping rate of 20 mL / min while stirring; after the addition is completed, stirring is continued for 1.5 hours to obtain a slurry.

[0029] Preferably, step (6) is specifically as follows: the slurry is spray-dried to obtain particles, and the particles are calcined at 550-650° C. for 5-7 hours to obtain a propylene ammoxidation catalyst.

[0030] Further preferably, the step (6) is specifically as follows: the slurry is spray-dried to obtain particles, and the particles are calcined at 550° C. for 6 hours to obtain a propylene ammoxidation catalyst.

[0031] On the other hand, the present invention provides a propylene ammoxidation catalyst with high abrasion resistance, which is prepared by the above preparation method and comprises components: a metal oxide and a carrier; wherein the stoichiometric composition of the metal oxide is M O12 Bi a Fe b A c B d C e O x ;

[0032] A is Re and Zr, and the molar ratio of Re to Zr is 3:0.5-2;

[0033] B is selected from at least one of Cs, Be, and Ca; C is selected from at least one of Al and Co; a, b, c, d, e, and x represent the molar ratios of the corresponding elements, a is 0.8-1.6, b is 2-3, c is 0.1-0.5, d is 0.1-0.3, and e is 0.3-0.9; x is a value that satisfies the charge balance of the catalyst;

[0034] The carrier is SiO2, and the particle size of SiO2 is 10-200nm.

[0035] Preferably, A is Re and Zr, and the molar ratio of Re to Zr is 3:1.

[0036] Preferably, the B is selected from at least two of Cs, Be and Ca; further preferably, the B is a mixture of Cs and Be, or a mixture of Cs and Ca.

[0037] More preferably, when B is a mixture of Cs and Be, the molar ratio of Cs to Be is 1:0.5-1.5; when B is a mixture of Cs and Ca, the molar ratio of Cs to Ca is 1:1.5-3.

[0038] More preferably, when B is a mixture of Cs and Be, the molar ratio of Cs to Be is 1:1; when B is a mixture of Cs and Ca, the molar ratio of Cs to Ca is 1:2.

[0039] Preferably, the C is Co.

[0040] Preferably, a is 1-1.4, b is 2.2-2.6, c is 0.2-0.3, d is 0.12-0.17, e is 0.4-0.6, and x is a value that satisfies the charge balance of the catalyst.

[0041] More preferably, a is 1.2, b is 2.5, c is 0.21, d is 0.15, e is 0.52, and x is a value that satisfies the charge balance of the catalyst.

[0042] Preferably, the specific surface area of ​​the propylene ammoxidation catalyst is 120-180m 2 / g; further preferably, the specific surface area is 150-160m 2 / g.

[0043] Preferably, in the propylene ammoxidation catalyst, the mass ratio of the metal oxide to the carrier is 3-5:5-7.

[0044] Further preferably, in the propylene ammoxidation catalyst, the mass ratio of the metal oxide to the carrier is 3.5:6.5.

[0045] Preferably, the carrier is from silica sol, and the mass concentration of SiO2 in the silica sol is 35-55%; further preferably, the mass concentration of SiO2 in the silica sol is 40-50%.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The propylene ammoxidation catalyst prepared by the present invention still has high reaction activity and selectivity after repeated use, and has high catalytic stability; the present invention selects several elements of Bi, Fe, Re, Zr, Cs, Be, Ca, Al, and Co to be coordinated with Mo, controls the mixing process of the Mo precursor solution and the carrier solution, improves the wear resistance of the propylene ammoxidation catalyst, and significantly reduces the wear rate.

[0048] 2. In the preparation process of the propylene ammoxidation catalyst of the present invention, a certain amount of sodium dodecyl sulfonate is added, and the obtained propylene ammoxidation catalyst has pores with uniform size distribution and significantly improved catalytic activity. DETAILED DESCRIPTION

[0049] The following non-limiting examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. The following content is merely an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, which should also fall within the scope of the present invention.

[0050] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those generally understood by those of ordinary skill in the art to which the present invention belongs.

[0051] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels.

[0052] In the following examples, the sodium dodecyl sulfate was purchased from Shandong Yousuo Chemical Technology Co., Ltd., model LAS-30; the silica sol was LUDOX AS-40. The above components, products from different manufacturers have no significant effect on the effect.

[0053] In the embodiments of the present invention, the molar ratio of each metal in the propylene ammoxidation catalyst is calculated as the molar ratio of each metal compound, and each metal compound is a metal compound used in the preparation of propylene ammoxidation catalyst in the art. In the present invention, the selection of metal compounds is not limited, and those skilled in the art can limit it according to actual conditions.

[0054] For example, in the embodiment of the present invention, the compound containing metal Mo is (NH4)2MoO4 or (NH4)6Mo7O 24 ·4H2O; the compound containing metal Bi is Bi(NO3)3·5H2O; the compound containing metal Fe is Fe(NO3)3·9H2O; the compound containing metal Re is Re(NO3)3·6H2O; the compound containing metal Zr is Zr(NO 3)4 ·5H2O or ZrO(NO3)2; the compound containing metal Cs is CsNO3 or Cs2CO3; the compound containing metal Be is Be(NO3)2·3H2O; the compound containing metal Ca is Ca(NO3)2·4H2O; the compound containing metal Al is Al(NO3)3·9H2O; the compound containing metal Co is Co(NO3)2·6H2O.

[0055] Example 1

[0056] A method for preparing a propylene ammoxidation catalyst with high abrasion resistance comprises the following steps:

[0057] (1) Prepare Mo precursor solution: dissolve 12 mol (NH4)2MoO4 in water to obtain Mo precursor solution with a mass concentration of 15%;

[0058] (2) Preparation of other metal solutions: Dissolve 1.2 mol Bi(NO3)3·5H2O, 2.5 mol Fe(NO3)3·9H2O, 1.575 mol Re(NO3)3·6H2O, 0.0525 mol Zr(NO3)4·5H2O, 0.075 mol CsNO3, 0.075 mol Be(NO3)2·3H2O and 0.52 mol Co(NO3)2·6H2O in water to obtain other metal solutions with a mass concentration of 25%;

[0059] (3) Preparation of carrier solution: Sodium dodecylbenzene sulfonate and silica sol are mixed to prepare a carrier solution; the mass concentration of sodium dodecylbenzene sulfonate is 0.5%, the mass fraction of SiO2 in silica sol is 40%, and the particle size of SiO2 is 20-50nm;

[0060] (4) At 45°C, add 50% of the Mo precursor solution into the carrier solution at a dropping rate of 20 mL / min while stirring; after the addition is completed, heat to 55°C and stir for 2 h to obtain a catalyst pretreatment solution;

[0061] (5) At 50°C, the catalyst pretreatment solution was mixed with other metal solutions and stirred for 1 hour; then the remaining Mo precursor solution was added dropwise at a rate of 20 mL / min while stirring; after the addition was completed, stirring was continued for 1.5 hours to obtain a slurry;

[0062] (6) The slurry is spray dried to obtain particles, which are then calcined at 550° C. for 6 h to obtain a propylene ammoxidation catalyst.

[0063] The obtained propylene ammoxidation catalyst, based on the molar ratio of each element, is M O12 Bi 1.2 Fe 2.5 (Re, Zr) 0.21 (Cs, Be) 0.15 Co 0.52 O x / SiO2, wherein the molar ratio of Re to Zr is 3:1; and the molar ratio of Cs to Be is 1:1.

[0064] In propylene ammoxidation catalysts, metal oxides (M O12 Bi a Fe b A c B d C e O x ) and the carrier have a mass ratio of 3.5:6.5.

[0065] Example 2

[0066] The difference from Example 1 is that the amount of each compound added in step (2) is changed: 1.0 mol Bi(NO3)3·5H2O, 2.2 mol Fe(NO3)3·9H2O, 0.15 mol Re(NO3)3·6H2O, 0.05 mol Zr(NO3)4·5H2O, 0.06 mol CsNO3, 0.06 mol Be(NO3)2·3H2O, 0.4 mol Co(NO3)2·6H2O.

[0067] The obtained propylene ammoxidation catalyst, based on the molar ratio of each element, is M O12 Bi 1.0 Fe 2.2 (Re, Zr) 0.2 (Cs, Be) 0.12 Co 0.4 Ox / SiO2, wherein the molar ratio of Re to Zr is 3:1; and the molar ratio of Cs to Be is 1:1.

[0068] In propylene ammoxidation catalysts, metal oxides (M O12 Bi a Fe b A c B d C e O x ) and the carrier have a mass ratio of 3.5:6.5.

[0069] Example 3

[0070] The difference from Example 1 is that the amount of each compound added in step (2) is changed to: 1.4 mol Bi(NO3)3·5H2O, 2.6 mol Fe(NO3)3·9H2O, 0.225 mol Re(NO3)3·6H2O, 0.075 mol Zr(NO3)4·5H2O, 0.085 mol CsNO3, 0.085 mol Be(NO3)2·3H2O, 0.6 mol Co(NO3)2·6H2O.

[0071] The obtained propylene ammoxidation catalyst, based on the molar ratio of each element, is M O12 Bi 1.4 Fe 2.6 (Re, Zr) 0.3 (Cs, Be) 0.17 Co 0.6 O x / SiO2, wherein the molar ratio of Re to Zr is 3:1; and the molar ratio of Cs to Be is 1:1.

[0072] In propylene ammoxidation catalysts, metal oxides (M O12 Bi a Fe b A c B d C e O x ) and the carrier have a mass ratio of 3.5:6.5.

[0073] Example 4

[0074] A method for preparing a propylene ammoxidation catalyst with high abrasion resistance comprises the following steps:

[0075] (1) Prepare Mo precursor solution: dissolve 12 mol (NH4)2MoO4 in water to obtain Mo precursor solution, with a mass concentration of (NH4)2MoO4 of 15%;

[0076] (2) Preparation of other metal solutions: 0.8 mol Bi(NO3)3·5H2O, 2 mol Fe(NO3)3·9H2O, 0.1 mol Re(NO3)3·6H2O and Zr(NO3)4·5H2O mixture (the molar ratio of NH4ReO4:ZrOCl2 is 3:0.5), 0.1 mol CsNO3 and Ca(NO3)2·4H2O mixture (the molar ratio of CsNO3:Ca(NO3)2·4H2O is 1:2), and 0.3 mol Al(NO3)3·9H2O are dissolved in water to obtain other metal solutions with a mass concentration of 30%;

[0077] (3) Preparation of carrier solution: Sodium dodecylbenzene sulfonate and silica sol are mixed to prepare a carrier solution; the mass concentration of sodium dodecylbenzene sulfonate is 0.5%, the mass fraction of SiO2 in silica sol is 40%, and the particle size of SiO2 is 20-50nm;

[0078] (4) At 45°C, add 50% of the Mo precursor solution into the carrier solution at a dropping rate of 15 mL / min while stirring; after the addition is completed, heat to 55°C and stir for 2 h to obtain a catalyst pretreatment solution;

[0079] (5) At 50°C, the catalyst pretreatment solution was mixed with other metal solutions and stirred for 1 hour; then the remaining Mo precursor solution was added dropwise at a rate of 15 mL / min while stirring; after the addition was completed, stirring was continued for 1.5 hours to obtain a slurry;

[0080] (6) The slurry is spray dried to obtain particles, which are then calcined at 650°C for 5 h to obtain a propylene ammoxidation catalyst.

[0081] The obtained propylene ammoxidation catalyst, based on the molar ratio of each element, is M O12 Bi 0.8 Fe2(Re, Zr) 0.1 (Cs, Ca) 0.1 Al 0.3 O x / SiO2, wherein the molar ratio of Re to Zr is 3:0.5; and the molar ratio of Cs to Ca is 1:2.

[0082] In propylene ammoxidation catalysts, metal oxides (M O12 Bi a Fe b A c B d C e O x ) and the carrier in a mass ratio of 3:7.

[0083] Example 5

[0084] A method for preparing a propylene ammoxidation catalyst with high abrasion resistance comprises the following steps:

[0085] (1) Prepare Mo precursor solution: dissolve 12 mol (NH4)2MoO4 in water to obtain Mo precursor solution, with a mass concentration of (NH4)2MoO4 of 15%;

[0086] (2) Preparation of other metal solutions: 1.6 mol Bi(NO3)3, 3.0 mol Fe(NO3)3·9H2O, 0.3 mol NH4ReO4, 0.2 mol ZrOCl2, 0.1 mol CsNO3, 0.2 mol CaO, and 0.9 mol Al(NO3)3 are dissolved in water to obtain other metal solutions; the mass concentration of other metal solutions is 25%;

[0087] (3) Preparation of carrier solution: Sodium dodecylbenzene sulfonate and silica sol are mixed to prepare a carrier solution; the mass concentration of sodium dodecylbenzene sulfonate is 0.5%, the mass fraction of SiO2 in silica sol is 40%, and the particle size of SiO2 is 20-50nm;

[0088] (4) At 45°C, add 50% of the Mo precursor solution into the carrier solution at a dropping rate of 25 mL / min while stirring; after the addition is completed, heat to 55°C and stir for 2 h to obtain a catalyst pretreatment solution;

[0089] (5) At 50°C, the catalyst pretreatment solution was mixed with other metal solutions and stirred for 1 hour; then the remaining Mo precursor solution was added dropwise at a rate of 25 mL / min while stirring; after the addition was completed, stirring was continued for 1.5 hours to obtain a slurry;

[0090] (6) The slurry is spray dried to obtain particles, which are then calcined at 650°C for 7 h to obtain a propylene ammoxidation catalyst.

[0091] The obtained propylene ammoxidation catalyst, based on the molar ratio of each element, is M O12 Bi 1.6 Fe3(Re, Zr) 0.5 (Cs, Ca) 0.3 Al 0.9 O x / SiO2, wherein the molar ratio of Re to Zr is 3:2; and the molar ratio of Cs to Ca is 1:2.

[0092] In propylene ammoxidation catalysts, metal oxides (M O12 Bi a Fe b A c Bd C e O x ) and the carrier have a mass ratio of 3.5:6.5.

[0093] Example 6

[0094] The difference from Example 1 is that in step (3), the mass concentration of sodium dodecyl sulfate is 0.7%. The rest is the same as Example 1.

[0095] Comparative Example 1

[0096] Different from Example 1, in step (2), ZrOCl2, CsNO3, and Be(NO3)2 are replaced by Ni(NO3)2, CrNO3, and Mg(NO3)2, respectively.

[0097] Specifically, other metal solutions were prepared: 1.2 mol Bi(NO3)3, 2.5 mol Fe(NO3)3·9H2O, 1.575 mol NH4ReO4, 0.0525 mol Ni(NO3)2, 0.075 mol CrNO3, 0.075 mol Mg(NO3)2, and 0.52 mol Co(NO3)2 were dissolved in water to obtain other metal solutions with a mass concentration of 25%.

[0098] The obtained propylene ammoxidation catalyst, based on the molar ratio of each element, is M O12 Bi 1.2 Fe 2.5 (Re,Ni) 0.21 (Cr, Mg) 0.15 Co 0.52 O x / SiO2, wherein the molar ratio of Re to Ni is 3:1; and the molar ratio of Cr to Mg is 1:1.

[0099] In propylene ammoxidation catalysts, metal oxides (M O12 Bi a Fe b A c B d C e O x ) and the carrier have a mass ratio of 3.5:6.5.

[0100] Comparative Example 2

[0101] Different from Example 1, the added amount of each compound is changed: 6.0 mol (NH4)2MoO4, 0.6 mol Bi(NO3)3·5H2O, 1.25 mol Fe(NO3)3·9H2O, 0.75 mol Re(NO3)3·6H2O, 0.25 mol Zr(NO3)4·5H2O, 0.25 mol CsNO3, 0.25 mol Be(NO3)2·3H2O, 1.04 mol Co(NO3)2·6H2O.

[0102] The propylene ammoxidation catalyst was prepared, and the molar ratio of each element was M O6.0 Bi 0.6 Fe 1.25 (Re, Zr) 1.0 (Cs, Be) 0.5 Co 1.04 O x / SiO2, wherein the molar ratio of Re to Zr is 3:1; and the molar ratio of Cs to Be is 1:1.

[0103] In propylene ammoxidation catalysts, metal oxides (M O12 Bi a Fe b A c B d C e O x ) and the carrier have a mass ratio of 3.5:6.5.

[0104] Comparative Example 3

[0105] Different from Example 1, in step (3), sodium dodecyl sulfate was not used.

[0106] Comparative Example 4

[0107] The difference from Example 1 is that in step (3), sodium dodecyl sulfate is replaced by cetyltrimethylammonium bromide (CTAB).

[0108] Comparative Example 5

[0109] Different from Example 1, the step (4) to step (5) does not involve the step of adding drops:

[0110] Steps (1) to (3) are the same as in Example 1;

[0111] (4) Mixing a 50% Mo precursor solution with a carrier solution at 45°C and stirring for 2 hours to obtain a catalyst pretreatment solution;

[0112] (5) At 50° C., the catalyst pretreatment solution was mixed with other metal solutions and stirred for 1 h; then mixed with the remaining Mo precursor solution and stirred for 1.5 h to obtain a slurry.

[0113] The rest are the same as in Example 1.

[0114] Comparative test

[0115] The catalytic activity and attrition index of the propylene ammoxidation catalysts prepared in the examples and comparative examples were tested.

[0116] 1. Catalytic activity performance evaluation method: 38 mm fluidized bed reactor, reaction temperature 420 ° C; reaction pressure 0.085 MPa; catalyst loading 300 g; catalyst propylene load (WWH): 0.085 h -1 ; Raw material ratio (molar): propylene / NH3 / air = 1 / 1.25 / 9.6. After running for 3 hours, the propylene conversion rate and acrylonitrile selectivity were recorded. The test results are shown in Table 1.

[0117] Propylene conversion rate (%) = (moles of propylene consumed in the reaction) / (moles of propylene fed) × 100%;

[0118] Acrylonitrile selectivity (%) = (number of moles of acrylonitrile produced by reaction) / (number of moles of propylene reacted) × 100%.

[0119] 2. Wear index evaluation method:

[0120] The NB / SH / D0964-2017 standard was used for testing and the hourly wear rate of the corresponding catalyst was calculated.

[0121] The hourly wear rate results of each catalyst are shown in Table 1.

[0122] Table 1

[0123]

[0124] In the same column of Table 1, the comparative example is compared with Example 1. # P≤0.05, ## P≤0.01, there is a significant difference.

[0125] As can be seen from Table 1, the propylene ammoxidation catalyst prepared by the present invention not only improves the propylene conversion rate and acrylonitrile selectivity by selecting the appropriate type of metal element and controlling the molar amount of the metal element, but also significantly improves the wear resistance of the catalyst, reduces the hourly wear rate of the catalyst, and thus increases the service life of the catalyst.

[0126] In addition, the invention adds a specific amount of sodium dodecyl sulfate, so that the pore size distribution of the propylene ammoxidation catalyst is uniform, the catalytic activity is improved, and the acrylonitrile selectivity is significantly improved; sodium dodecyl sulfate protects the catalyst to a certain extent, reduces the hourly wear rate, and improves the catalytic stability.

[0127] The present invention drips a precursor solution of Mo so that Mo and other metals are combined on a carrier, exposing more catalytic active sites, significantly improving propylene conversion rate and acrylonitrile selectivity; the metals interact with each other to reduce the wear rate of the catalyst.

[0128] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing a propylene ammoxidation catalyst with high abrasion resistance, characterized in that: Includes steps: (1) Preparing a Mo precursor solution: dissolving Mo salt in water to obtain a Mo precursor solution; (2) Preparation of other metal solutions: dissolving compounds containing other metals in water to obtain other metal solutions; (3) Preparation of carrier solution: Sodium dodecylbenzene sulfonate and silica sol are mixed to prepare a carrier solution; in the carrier solution, the mass concentration of sodium dodecylbenzene sulfonate is 0.1-1%, and the mass solubility of SiO2 in the silica sol is 30-60%; (4) adding 40-60% of the Mo precursor solution into the support solution at a temperature range of 35-55° C. and stirring to obtain a catalyst pretreatment solution; (5) The catalyst pretreatment solution is mixed with other metal solutions, stirred at 40-55°C, and then the remaining amount of Mo precursor solution is added dropwise, and stirred to obtain a slurry; (6) After the slurry is spray-dried, it is calcined at 500-700°C for 4-8h to obtain a propylene ammoxidation catalyst; In step (2), the other metal is selected from at least one of Bi, Fe, Re, Zr, Cs, Be, Ca, Al, and Co; The propylene ammoxidation catalyst comprises components: a metal oxide and a carrier; Among them, the stoichiometric composition of the metal oxide is M O12 Bi a Fe b A c B d C e O x ; A is Re and Zr, and the molar ratio of Re to Zr is 3:0.5-2; The B is a mixture of Cs and Be, or a mixture of Cs and Ca; C is selected from at least one of Al and Co; a, b, c, d, e and x represent the molar ratios of the corresponding elements, a is 0.8-1.6, b is 2-3, c is 0.1-0.5, d is 0.1-0.3, and e is 0.3-0.9; x is a value that satisfies the charge balance of the catalyst; The carrier is SiO2, and the particle size of SiO2 is 10-200nm.

2. The preparation method according to claim 1, characterized in that: In step (1), the mass concentration of Mo salt in the Mo precursor solution is 10-20%.

3. The preparation method according to claim 1, characterized in that: In step (2), in the other metal solution, the total mass concentration of other metal compounds is 20-35%.

4. The preparation method according to claim 1, characterized in that: In step (3), the mass concentration of sodium dodecylbenzene sulfonate in the carrier solution is 0.3-0.7%; the mass concentration of SiO2 in the silica sol is 35-55%.

5. The preparation method according to claim 4, characterized in that: The mass concentration of the sodium dodecylbenzene sulfonate is 0.5%; the mass concentration of SiO2 in the silica sol is 40-50%.

6. The preparation method according to claim 1, characterized in that: In the silica sol of step (3), the particle size of SiO2 is 10-200nm.

7. The preparation method according to claim 1, characterized in that: Step (4) is specifically as follows: within a temperature range of 40-50° C., a 50-55% formula amount of a Mo precursor solution is added dropwise to the carrier solution at a dropping speed of 15-25 mL / min, with stirring during the dropping; after the dropping is completed, the temperature is raised to 55-60° C. and stirred for 1.5-3 h to obtain a catalyst pretreatment solution; Step (5) is specifically as follows: at a temperature range of 45-50° C., the catalyst pretreatment solution is mixed with other metal solutions and stirred for 0.5-1.5 h; then the remaining amount of the Mo precursor solution is added dropwise at a rate of 15-25 mL / min while stirring; after the addition is completed, stirring is continued for 1-2 h to obtain a slurry; Step (6) is specifically as follows: the slurry is spray-dried to obtain particles, and the particles are calcined at 550-650° C. for 5-7 hours to obtain a propylene ammoxidation catalyst.

8. A propylene ammoxidation catalyst with high abrasion resistance, prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The invention comprises components: a metal oxide and a carrier; Among them, the stoichiometric composition of the metal oxide is M O12 Bi a Fe b A c B d C e O x ; A is Re and Zr, and the molar ratio of Re to Zr is 3:0.5-2; The B is a mixture of Cs and Be, or a mixture of Cs and Ca; C is selected from at least one of Al and Co; a, b, c, d, e and x represent the molar ratios of the corresponding elements, a is 0.8-1.6, b is 2-3, c is 0.1-0.5, d is 0.1-0.3, and e is 0.3-0.9; x is a value that satisfies the charge balance of the catalyst; The carrier is SiO2, and the particle size of SiO2 is 10-200nm.

9. The propylene ammoxidation catalyst according to claim 8, characterized in that A is Re and Zr, and the molar ratio of Re to Zr is 3:1; The B is a mixture of Cs and Be, or a mixture of Cs and Ca; The C is Co; a is 1-1.4, b is 2.2-2.6, c is 0.2-0.3, d is 0.12-0.17, e is 0.4-0.6, and x is a value that satisfies the charge balance of the catalyst; The mass ratio of metal oxide to carrier is 3-5:5-7.

10. The propylene ammoxidation catalyst according to claim 9, characterized in that When B is a mixture of Cs and Be, the molar ratio of Cs to Be is 1:0.5-1.5; when B is a mixture of Cs and Ca, the molar ratio of Cs to Ca is 1:1.5-3; a is 1.2, b is 2.5, c is 0.21, d is 0.15, e is 0.52, and x is the value that satisfies the charge balance of the catalyst; The mass ratio of metal oxide to support is 3.5:6.5.

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