Ammonia oxidation catalyst and its preparation method and application

Abstract

The present invention relates to an ammonia oxidation catalyst and a preparation method and application thereof. The ammonia oxidation catalyst belongs to a V-Rh system catalyst. By accurately limiting the stoichiometric ratio of V to Rh in the active component to 1.0:(0.05-5), and limiting the stoichiometric ratio of B-type, C-type and D-type metal elements, the ammonia oxidation catalyst can not only improve product selectivity, reduce the deep oxidation degree of raw materials, improve raw material conversion rate, and reduce raw material waste, but also has high stability and mechanical strength, is suitable for large-scale industrial production and application, and is particularly suitable for application in preparing isophthalonitrile by ammoxidation of meta-xylene.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, in particular to an ammonia oxidation catalyst and a preparation method and application thereof. Background Art

[0002] Aromatic nitrile cyano has high chemical activity. It can be used to synthesize various fine chemical products through hydrogenation and condensation reactions. It has been widely used in many industries such as medicine, fragrance, pesticide and resin. As an important source of raw materials, the demand for aromatic nitrile has shown an increasing trend at home and abroad in recent years. The synthesis principle is that aromatic nitrile cyano is oxidized by aromatic hydrocarbon ammoxidation under the conditions of ammonia and catalyst to obtain aromatic nitrile. Since the above manufacturing process has the advantages of simple operation, safe operation, high yield and low pollution, many scholars at home and abroad have invested a lot of research on it in order to achieve wide application.

[0003] In the 1950s, Allied took the lead in the research and development of aromatic hydrocarbon ammoxidation technology. At the same time, many companies, such as Distiller and Bayer, also began to study related ammoxidation catalysts. In 1969, Japan Catalyst Chemical Industry Co., Ltd. built a mixed aromatic hydrocarbon ammoxidation method to produce phthalonitrile and benzonitrile production equipment using its own technology. In 1970, a Japanese company and an American company cooperated to build an isophthalonitrile production unit. After that, Mitsubishi Gas Chemical of Japan successfully built an isophthalonitrile industrial production unit with Bagder Company of the United States, making aromatic hydrocarbon ammoxidation technology popular and applied.

[0004] CN106268890A discloses a mixed catalyst V for the oxidation of aromatic hydrocarbons 1.0 Cr a A b B c C d M e O x , wherein A is selected from at least one of P, B, Bi, Sb, and As; B is selected from at least one of Mn, Ni, Co, Ti, Sn, Mo, or rare earth elements; C is selected from at least one of alkali metals or alkaline earth metals; and M is selected from at least one of Zr and W. The wear resistance of the catalyst described in the patent is optimized, and the wear rate is reduced by about 22% compared with the comparative catalyst in the literature.

[0005] CN106362760A discloses a mixed ammonia oxidation catalyst V 1.0 Cr a A b B c C d D e Ef M g O x , wherein A is selected from at least one element in Group IIIA of the periodic table; B is selected from at least one element in Group VA of the periodic table; C is selected from at least one element of alkali metals or alkaline earth metals; D is selected from at least one element in Group VIII of the periodic table; E is selected from at least one of Mo, Ti, and Nb; and M is selected from at least one of Zr and W. The method described in the patent effectively improves the wear resistance of the catalyst while maintaining the high activity selectivity of the catalyst. The obtained catalyst can be applied to the industrial production of aromatic hydrocarbon ammoxidation.

[0006] CN102218334B discloses an antimony-containing ammonia oxidation catalyst V 1.0 Sb a A b B c C d O x , wherein A is at least one selected from lithium, sodium, potassium, rubidium or cesium; B is at least one selected from magnesium, calcium, barium, chromium, tungsten, molybdenum, manganese, iron, cobalt, nickel or tin; C is at least one selected from boron or phosphorus. The catalyst better solves the problems in the prior art that the catalyst is difficult to adapt to the requirements of the fluidized bed and the raw material cost is high, and can be used for industrial production.

[0007] In summary, the existing technology optimizes the wear resistance and raw material cost of ammonia oxidation catalysts, but does not mention how to reduce the deep oxidation degree of the reaction raw materials and reduce the selectivity of small molecule products such as carbon dioxide and carbon monoxide. Therefore, it is urgent to develop a new type of ammonia oxidation catalyst and its preparation method, which can not only improve product selectivity, reduce the deep oxidation degree of raw materials, increase raw material conversion rate, and reduce raw material waste, but also improve the stability and mechanical strength of the ammonia oxidation catalyst, which is suitable for large-scale industrial production applications. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides an ammonia oxidation catalyst and a preparation method and application thereof. The ammonia oxidation catalyst belongs to a V-Rh system catalyst, which can not only improve product selectivity, reduce the deep oxidation degree of raw materials, improve raw material conversion rate, and reduce raw material waste, but also has high stability and mechanical strength, and is suitable for large-scale industrial production applications, especially for the application in the preparation of isophthalonitrile by ammoxidation of meta-xylene.

[0009] One of the purposes of the present invention is to provide an ammonia oxidation catalyst, the ammonia oxidation catalyst comprising a carrier and an active component, the active component calculated by atomic ratio satisfies the following structural formula: V 1.0 R a B b C c Dd O x ;

[0010] Wherein, B is selected from any one or a combination of at least two of Sc, Mn, Ga or Mo, C is selected from any one or a combination of at least two of Zr, Y, Tc or Ag, and D is selected from any one or a combination of at least two of As, Bi, P or Sb;

[0011] a=0.05-5, b=0.01-2, c=0.001-1, d=0.001-1, x=2.0-9.0, and x is a value determined by the oxidation degree of other elements.

[0012] The ammonia oxidation catalyst of the present invention belongs to a V-Rh system catalyst. By accurately limiting the stoichiometric ratio of V to Rh in the active component to 1.0:(0.05-5), and limiting the stoichiometric ratio of the B-type metal elements, an effective composite reaction active site can be formed, which enables the active component and the carrier to form a synergistic reaction active site, effectively reducing the activation energy of the ammonia oxidation reaction, increasing the adsorption amount of ammonia, reducing the deep oxidation degree of raw materials such as meta-xylene, reducing the generation of small molecule products, and ensuring the conversion rate of raw materials such as meta-xylene and product selectivity.

[0013] Furthermore, the ammonia oxidation catalyst of the present invention can effectively ensure the stability and mechanical strength of the ammonia oxidation catalyst by accurately defining the stoichiometric ratio of type C and type D metal elements in the active components, and ensure the stability of the ammonia oxidation catalyst during long-term operation.

[0014] It is worth noting that in the structural formula V 1.0 R a B b C c D d O x wherein a=0.05-5, for example, 0.05, 0.1, 0.3, 0.5, 0.7, 1, 1.5, 2, 3, 3.5, 4 or 5, b=0.01-2, for example, 0.01, 0.03, 0.05, 0.08, 0.1, 0.3, 0.5, 0.7, 1, 1.3, 1.5, 1.7 or 2, and c=0.001-1, for example, 0.001, 0.003, 0.005 , 0.008, 0.01, 0.03, 0.05, 0.08, 0.1, 0.3, 0.5 or 1, etc., d = 0.001-1, for example, 0.001, 0.003, 0.005, 0.008, 0.01, 0.03, 0.05, 0.08, 0.1, 0.3, 0.5 or 1, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0015] As a preferred technical solution of the present invention, in the structural formula V 1.0 R a B b C c D d O x wherein a=0.08-3, for example, 0.08, 0.15, 0.35, 0.65, 0.85, 1.2, 1.8, 2.3, 2.5, 2.8 or 3, b=0.05-1, for example, 0.05, 0.07, 0.11, 0.15, 0.25, 0.45, 0.65, 0.85, 0.9 or 1, c=0.05-0.8, for example, 0.05, 0.06, 0.07, 0.09, 0.12, 0.2, 0.4, 0.6 or 0.8, etc., d = 0.01-0.5, for example, 0.01, 0.02, 0.04, 0.06, 0.09, 0.12, 0.15, 0.23, 0.35, 0.45 or 0.5, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0016] As a preferred technical solution of the present invention, based on the total mass of the ammonia oxidation catalyst, the mass percentage of the active component is 20-70%, and the remainder is the carrier.

[0017] It is worth noting that the mass percentage of the active component of the present invention is 20-70%, for example 20%, 30%, 40%, 50%, 60% or 70%, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0018] Preferably, the carrier is an MFI structured molecular sieve, which is an artificially synthesized Al2O3 / SiO2 type molecular sieve having a double ten-membered ring cross-channel structure.

[0019] Preferably, the carrier is an Al2O3 / SiO2 type molecular sieve, and the silicon-aluminum ratio (molar ratio of SiO2 to Al) is 1:(0.001-0.1), for example, 1:0.001, 1:0.005, 1:0.01, 1:0.03, 1:0.05, 1:0.07 or 1:0.1, etc., preferably 1:(0.005-0.07), for example, 1:0.005, 1:0.007, 1:0.009, 1:0.02, 1:0.04, 1:0.06 or 1:0.07, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0020] A second object of the present invention is to provide a method for preparing the ammonia oxidation catalyst described in the first object, the method comprising the following steps:

[0021] (1) preparing an aqueous solution containing various metal elements according to the structural formula of the active component in the ammonia oxidation catalyst, and mixing the aqueous solution with an oxalic acid solution to form a reaction solution A;

[0022] (2) mixing the reaction solution A described in step (1) with the reaction solution B containing the carrier or a compound containing the carrier to form an impregnation mixed solution;

[0023] (3) The impregnation mixed solution of step (2) is sequentially evaporated, concentrated, dried and calcined to obtain the ammonia oxidation catalyst.

[0024] The preparation method of the ammonia oxidation catalyst of the present invention is to obtain a reaction liquid A according to the structural formula of the active component, and the reaction liquid B containing the carrier or the compound containing the carrier is a slurry. After the reaction liquid A and the reaction liquid B are mixed, the solid components in the compound containing the carrier or the compound containing the carrier are immersed in the reaction liquid A, and the obtained impregnated mixed liquid is evaporated, concentrated, dried and roasted in sequence to obtain the ammonia oxidation catalyst.

[0025] As a preferred technical solution of the present invention, the method for preparing the reaction solution B in step (2) comprises the following steps:

[0026] An aluminum source and a silicon source are mixed to obtain a first mixed solution, and the first mixed solution is then mixed with an auxiliary agent to obtain a second mixed solution, and the reaction solution B is obtained after aging treatment.

[0027] It is worth noting that the reaction solution B containing a carrier or a compound containing a carrier described in the present invention is a homemade slurry, and an additive is added to control the size of the pores in the carrier, which is beneficial for the target raw material to enter the pores and combine with the reaction active sites during the ammonia oxidation catalytic reaction.

[0028] As a preferred technical solution of the present invention, the aluminum source includes sodium aluminate and / or aluminum sulfate.

[0029] Preferably, the silicon source includes tetraethyl orthosilicate and / or silica sol.

[0030] Preferably, the silicon-aluminum ratio (molar ratio of SiO2 to Al) of the silicon source and the aluminum source is 1:(0.001-0.1), for example, 1:0.001, 1:0.005, 1:0.008, 1:0.01, 1:0.03, 1:0.05, 1:0.07, 1:0.09 or 1:0.1, etc., preferably 1:(0.005-0.07), for example, 1:0.005, 1:0.007, 1:0.009, 1:0.015, 1:0.02, 1:0.04, 1:0.06 or 1:0.07, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are equally applicable.

[0031] It is worth noting that the reaction liquid B containing a carrier or a compound containing a carrier described in the present invention is a self-made slurry. By accurately adjusting the silicon-aluminum ratio of the reaction liquid B to 1: (0.001-0.1), the Al2O3 content in the carrier can be accurately adjusted, and then the acid amount of the carrier can be regulated to provide more ammonia adsorption sites for the subsequent ammonia oxidation reaction. If the silicon-aluminum ratio is higher than the range selected by this patent, the acid sites are insufficient, the adsorption capacity of ammonia is insufficient, and the effect of reducing the degree of xylene oxidation cannot be achieved; if the silicon-aluminum ratio is lower than the range selected by this patent, the strong acid sites increase, resulting in excessive adsorption of ammonia, and it is difficult to react with xylene for ammonia oxidation, resulting in a deepening of the degree of carbon dioxide generated by the deep oxidation of xylene.

[0032] Preferably, the auxiliary agent includes any one of glycerol, organic amine or quaternary ammonium salt, preferably glycerol.

[0033] It is worth noting that the reaction liquid B containing a carrier or a compound containing a carrier described in the present invention is a homemade slurry. By adding glycerol as an auxiliary agent, it can take advantage of the strong hydrogen bonding force between glycerol molecules and the strong dipole moment, and has a good auxiliary effect on the pore expansion modification of SiO2 and the increase of acidic sites. It can effectively control the size of the pores in the carrier to be equivalent to the molecular dynamics diameter of benzene (about 0.6nm), that is, improve the shape selectivity, and can also enhance the adsorption of ammonia, improve the selectivity of aromatic products, and reduce the degree of deep oxidation of raw materials.

[0034] Preferably, the molar ratio of the auxiliary agent to the silicon element in the silicon source is 0.1 to 30, for example, 0.1, 0.5, 1, 3, 5, 8, 10, 15, 20, 25 or 30, etc., preferably 0.5 to 20, for example, 0.5, 1.5, 2, 4, 7, 9, 11, 13, 16, 18 or 20, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0035] Preferably, the aging treatment time is 6 to 24 hours, for example 6 hours, 12 hours, 18 hours or 24 hours, etc., preferably 8 to 20 hours, for example 8 hours, 9 hours, 10 hours, 11 hours, 13 hours, 14 hours, 15 hours, 17 hours, 19 hours or 20 hours, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0036] Preferably, the temperature of the aging treatment is 40-120°C, for example, 40°C, 50°C, 60°C, 80°C, 100°C or 120°C, etc., preferably 50-100°C, for example, 50°C, 55°C, 65°C, 75°C, 85°C, 95°C or 100°C, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0037] As a preferred technical solution of the present invention, the temperature of the evaporation concentration in step (3) is 40-100°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0038] Preferably, the evaporation and concentration in step (3) obtains a slurry liquid with a solid content of 35-75%. The solid content can be 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or 75%, etc., but is not limited to the listed values. Other values ​​not listed within the above numerical range are also applicable.

[0039] As a preferred technical solution of the present invention, the drying in step (3) is spray drying.

[0040] Preferably, the inlet temperature of the spray drying is 180-280°C, for example, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C or 280°C, and the outlet temperature is 110-180°C, for example, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0041] As a preferred technical solution of the present invention, the heating rate of the roasting in step (3) is 1 to 10°C / min, for example, 1°C / min, 3°C / min, 5°C / min, 7°C / min or 10°C / min, etc., preferably 2 to 6°C / min, for example, 2°C / min, 2.5°C / min, 3.5°C / min, 4.5°C / min, 5.5°C / min or 6°C / min, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0042] Preferably, the roasting in step (3) includes primary roasting and secondary roasting.

[0043] Preferably, the temperature of the primary calcination is 120-170°C, for example, 120°C, 130°C, 140°C, 150°C, 160°C or 170°C, etc., preferably 120-150°C, for example, 120°C, 125°C, 135°C, 145°C or 150°C, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0044] Preferably, the primary calcination time is 3 to 12 h, for example 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h or 12 h, but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0045] Preferably, the temperature of the secondary calcination is 600-750°C, for example 600°C, 620°C, 650°C, 680°C, 700°C, 720°C or 750°C, etc., preferably 620-700°C, for example 620°C, 640°C, 660°C, 670°C or 700°C, etc., but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0046] Preferably, the secondary calcination time is 4 to 10 h, for example 4 h, 5 h, 6 h, 7 h, 8 h, 9 h or 10 h, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0047] A third object of the present invention is to provide a method for preparing isophthalonitrile, which comprises the following contents:

[0048] Using the ammonia oxidation catalyst described in the first purpose, or using the ammonia oxidation catalyst obtained by the preparation method described in the second purpose, meta-xylene ammonia and oxygen-containing gas are subjected to an ammonia oxidation reaction under the action of the ammonia oxidation catalyst to obtain isophthalonitrile.

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

[0050] (1) The ammoxidation catalyst of the present invention belongs to a V-Rh system catalyst. By accurately limiting the stoichiometric ratio of V to Rh in the active component to 1.0:(0.05-5), and limiting the stoichiometric ratio of B, C and D metal elements, it can not only improve product selectivity, reduce the degree of deep oxidation of raw materials, increase raw material conversion rate, and reduce raw material waste, but also has high stability and mechanical strength, and is suitable for large-scale industrial production applications, especially for the application in the preparation of isophthalonitrile by ammoxidation of meta-xylene;

[0051] (2) The carrier in the ammonia oxidation catalyst of the present invention is a self-made micron Al2O3 / SiO2 molecular sieve. By accurately adjusting the silicon-aluminum ratio of the reaction solution B to 1:(0.001-0.1) during the preparation process, the Al2O3 content in the carrier can be accurately adjusted, and then the acid content of the carrier can be regulated to provide more ammonia adsorption sites for the subsequent ammonia oxidation reaction;

[0052] (3) The carrier in the ammonia oxidation catalyst of the present invention is a self-made micron Al2O3 / SiO2 type molecular sieve. By adding glycerol or the like as an auxiliary agent, the advantages of strong hydrogen bonding force between glycerol molecules and strong dipole moment can be utilized to have a good auxiliary effect on the pore expansion modification of SiO2 and the increase of acidic sites. The size of the pores in the carrier can be effectively controlled to be equivalent to the molecular dynamics diameter of benzene (about 0.6 nm), that is, the shape selectivity is improved, and the adsorption of ammonia can be enhanced, thereby improving the selectivity of aromatic products and reducing the deep oxidation degree of the raw materials. DETAILED DESCRIPTION

[0053] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] The raw materials used in the examples are all conventional raw materials in the art, and the purity specification used is AR grade.

[0055] The calculation formulas for the conversion of raw material meta-xylene and the selectivity of target product isophthalonitrile in the embodiment are as follows:

[0056] Meta-xylene conversion rate (%) = (the number of moles of meta-xylene reacted / the number of moles of meta-xylene fed) × 100%;

[0057] Isophthalonitrile selectivity (%) = (the number of moles of isophthalonitrile produced / the number of moles of meta-xylene reacted) × 100%.

[0058] Example 1

[0059] This embodiment provides an ammonia oxidation catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps:

[0060] (1) 66.04 g of oxalic acid was added to 202 g of hot water at 85° C. to form an oxalic acid solution. According to the structural formula of the active component in the ammonia oxidation catalyst, 44.6 g of vanadium pentoxide was first slowly added to the oxalic acid solution. Then 6.354 g of rhodium acetate, 4.8066 g of ammonium molybdate, 10.528 g of zirconium nitrate, and 0.889 g of arsenic chloride were dissolved in 30 g, 30 g, 20 g, and 15 g of water, respectively, and added to the oxalic acid solution to form a reaction solution A.

[0061] (2) adding the reaction solution B containing the carrier compound to the reaction solution A described in step (1) to form an impregnation mixed solution;

[0062] The preparation method of the reaction solution B comprises the following steps: adding 2.49 g of NaAlO2 to 95 g of water, stirring at room temperature until completely dissolved to form an aluminum source; adding the aluminum source to 303.4 g of silica sol with a mass percentage of 40%, mixing to obtain a first mixed solution, then adding 53.176 g of glycerol to the first mixed solution, mixing to obtain a second mixed solution, and aging at 80° C. for 12 h to obtain the reaction solution B;

[0063] (3) The impregnation mixed solution of step (2) is evaporated and concentrated at 85° C. until a slurry liquid with a solid content of 60% is obtained; the obtained slurry liquid is spray-dried under the conditions of an inlet temperature of 250° C. and an outlet temperature of 170° C. to obtain a catalyst precursor; the obtained catalyst precursor is placed in a muffle furnace, heated to 140° C. at a heating rate of 2° C. / min and kept warm for 4 h for primary calcination, heated to 630° C. at a heating rate of 2° C. / min and kept warm for 5 h for secondary calcination, and finally cooled to room temperature to obtain an ammonia oxidation catalyst 1#.

[0064] After testing, the active component ratio in the above-mentioned ammonia oxidation catalyst 1# is V 1.0 R 0.08 Mo 0.05 Zr 0.05 As 0.01 O 2.895 .

[0065] The ammonia oxidation catalyst 1# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The feed ratio of the reaction raw materials was 1:3.1:12 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 370°C, the reaction pressure (gauge pressure) was 36 kPa, and the catalyst weight load in the reactor was 0.032 h -1 .

[0066] After the reactor was operated for 200 hours, the conversion rate of meta-xylene was 99.8% and the selectivity of isophthalonitrile was 99.6%.

[0067] Example 2

[0068] This embodiment provides an ammonia oxidation catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps:

[0069] (1) 66.04 g of oxalic acid was added to 202 g of hot water at 85° C. to form an oxalic acid solution. According to the structural formula of the active component in the ammonia oxidation catalyst, 44.6 g of vanadium pentoxide was first slowly added to the oxalic acid solution. Then, 79.426 g of rhodium acetate, 48.066 g of ammonium molybdate, 84.221 g of zirconium nitrate, and 44.453 g of arsenic chloride were dissolved in 300 g, 300 g, 160 g, and 150 g of water, respectively, and added to the oxalic acid solution to form a reaction solution A.

[0070] (2) adding the reaction solution B containing the carrier compound to the reaction solution A described in step (1) to form an impregnation mixed solution;

[0071] The preparation method of the reaction solution B comprises the following steps: adding 0.166 g of NaAlO2 to 95 g of water, stirring at room temperature until completely dissolved to form an aluminum source; adding the aluminum source to 303.4 g of silica sol with a mass percentage of 40%, mixing to obtain a first mixed solution, then adding 53.176 g of glycerol to the first mixed solution, mixing to obtain a second mixed solution, and aging at 70° C. for 10 hours to obtain the reaction solution B;

[0072] (3) The impregnation mixed solution of step (2) is evaporated and concentrated at 85° C. until a slurry liquid with a solid content of 60% is obtained; the obtained slurry liquid is spray-dried under the conditions of an inlet temperature of 230° C. and an outlet temperature of 130° C. to obtain a catalyst precursor; the obtained catalyst precursor is placed in a muffle furnace, heated to 150° C. at a heating rate of 2° C. / min and kept warm for 6 h for primary calcination, heated to 660° C. at a heating rate of 2° C. / min and kept warm for 7 h for secondary calcination, and finally cooled to room temperature to obtain an ammonia oxidation catalyst 2#.

[0073] After testing, the active component ratio in the above-mentioned ammonia oxidation catalyst 2# is V 1.0 R 1.0 Mo 0.5 Zr 0.4 As 0.5 O 7.55 .

[0074] The ammonia oxidation catalyst 2# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The feed ratio of the reaction raw materials was 1:3.5:11 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 365°C, the reaction pressure (gauge pressure) was 27 kPa, and the catalyst weight load in the reactor was 0.04 h -1 .

[0075] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 99.3% and the selectivity of isophthalonitrile was 99.1%.

[0076] Example 3

[0077] This embodiment provides an ammonia oxidation catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps:

[0078] (1) 66.04 g of oxalic acid was added to 202 g of hot water at 85° C. to form an oxalic acid solution. According to the structural formula of the active component in the ammonia oxidation catalyst, 44.6 g of vanadium pentoxide was first slowly added to the oxalic acid solution. Then, 39.713 g of rhodium acetate, 24.033 g of ammonium molybdate, 42.111 g of zirconium nitrate, and 22.227 g of arsenic chloride were dissolved in 150 g, 150 g, 80 g, and 75 g of water, respectively, and added to the oxalic acid solution to form a reaction solution A.

[0079] (2) adding the reaction solution B containing the carrier compound to the reaction solution A described in step (1) to form an impregnation mixed solution;

[0080] The preparation method of the reaction solution B comprises the following steps: adding 1.656 g of NaAlO2 to 95 g of water, stirring at room temperature until completely dissolved to form an aluminum source; adding the aluminum source to 303.4 g of silica sol with a mass percentage of 40%, mixing to obtain a first mixed solution, then adding 53.176 g of glycerol to the first mixed solution, mixing to obtain a second mixed solution, and aging at 80° C. for 12 h to obtain the reaction solution B;

[0081] (3) The impregnation mixed solution of step (2) is evaporated and concentrated at 85° C. until a slurry liquid with a solid content of 60% is obtained; the obtained slurry liquid is spray-dried under the conditions of an inlet temperature of 240° C. and an outlet temperature of 160° C. to obtain a catalyst precursor; the obtained catalyst precursor is placed in a muffle furnace, heated to 140° C. at a heating rate of 2° C. / min and kept warm for 5 h for primary calcination, heated to 650° C. at a heating rate of 2° C. / min and kept warm for 6 h for secondary calcination, and finally cooled to room temperature to obtain an ammonia oxidation catalyst 3#.

[0082] After testing, the active component ratio in the above ammonia oxidation catalyst 3# is V 1.0 R 0.5 Mo 0.25 Zr 0.2 As 0.25 O 5.025 .

[0083] The ammonia oxidation catalyst 3# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The feed ratio of the reaction raw materials was 1:2.1:10.1 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 360°C, the reaction pressure (gauge pressure) was 29 kPa, and the catalyst weight load in the reactor was 0.037 h -1 .

[0084] After the reactor was operated for 200 hours, the conversion rate of meta-xylene was 99.9% and the selectivity of isophthalonitrile was 99.8%.

[0085] Example 4

[0086] This embodiment provides an ammonia oxidation catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps:

[0087] (1) 66.04 g of oxalic acid was added to 202 g of hot water at 85° C. to form an oxalic acid solution. According to the structural formula of the active component in the ammonia oxidation catalyst, 44.6 g of vanadium pentoxide was first slowly added to the oxalic acid solution. Then, 3.97 g of rhodium acetate, 12.016 g of ammonium molybdate, 21.055 g of zirconium nitrate, and 11.113 g of arsenic chloride were dissolved in 75 g, 75 g, 40 g, and 40 g of water, respectively, and added to the oxalic acid solution to form a reaction solution A.

[0088] (2) adding the reaction solution B containing the carrier compound to the reaction solution A described in step (1) to form an impregnation mixed solution;

[0089] The preparation method of the reaction solution B comprises the following steps: adding 16.557 g of NaAlO2 to 95 g of water, stirring at room temperature until completely dissolved to form an aluminum source; adding the aluminum source to 303.4 g of silica sol with a mass percentage of 40%, mixing to obtain a first mixed solution, then adding 53.176 g of glycerol to the first mixed solution, mixing to obtain a second mixed solution, and aging at 80° C. for 12 hours to obtain the reaction solution B;

[0090] (3) The impregnation mixed solution of step (2) is evaporated and concentrated at 85° C. until a slurry liquid with a solid content of 60% is obtained; the obtained slurry liquid is spray-dried at an inlet temperature of 250° C. and an outlet temperature of 170° C. to obtain a catalyst precursor; the obtained catalyst precursor is placed in a muffle furnace, heated to 170° C. at a heating rate of 2° C. / min and kept warm for 5 h for primary calcination, heated to 650° C. at a heating rate of 2° C. / min and kept warm for 6 h for secondary calcination, and finally cooled to room temperature to obtain an ammonia oxidation catalyst 4#.

[0091] After testing, the active component ratio in the above-mentioned ammonia oxidation catalyst 4# is V 1.0R 0.1 Mo 0.125 Zr 0.1 As 0.125 O 3.5375 .

[0092] The ammonia oxidation catalyst 4# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The feed ratio of the reaction raw materials was 1:3.8:13 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 365°C, the reaction pressure (gauge pressure) was 40 kPa, and the catalyst weight load in the reactor was 0.042 h -1 .

[0093] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 99.7% and the selectivity of isophthalonitrile was 99.4%.

[0094] Example 5

[0095] This embodiment provides an ammonia oxidation catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps:

[0096] (1) 66.04 g of oxalic acid was added to 202 g of hot water at 85° C. to form an oxalic acid solution. According to the structural formula of the active component in the ammonia oxidation catalyst, 44.6 g of vanadium pentoxide was first slowly added to the oxalic acid solution, and then 6.87 g of rhodium acetate, 0.3135 g of gallium nitrate, 0.00042 g of silver nitrate, and 0.0000048 g of bismuth nitrate were dissolved in 140 g, 20 g, 10 g, and 10 g of water, respectively, and added to the above oxalic acid solution, and mixed to form a reaction solution A;

[0097] (2) adding the reaction solution B containing the carrier compound to the reaction solution A described in step (1) to form an impregnation mixed solution;

[0098] The preparation method of the reaction solution B comprises the following steps: adding 1.656 g of NaAlO2 to 95 g of water, stirring at room temperature until completely dissolved to form an aluminum source; adding the aluminum source to 303.4 g of silica sol with a mass percentage of 40%, mixing to obtain a first mixed solution, then adding 53.176 g of glycerol to the first mixed solution, mixing to obtain a second mixed solution, and aging at 80° C. for 12 h to obtain the reaction solution B;

[0099] (3) The impregnation mixed solution of step (2) is evaporated and concentrated at 85° C. until a slurry liquid with a solid content of 60% is obtained; the obtained slurry liquid is spray-dried at an inlet temperature of 250° C. and an outlet temperature of 170° C. to obtain a catalyst precursor; the obtained catalyst precursor is placed in a muffle furnace, heated to 140° C. at a heating rate of 2° C. / min and kept warm for 4 h for primary calcination, heated to 630° C. at a heating rate of 2° C. / min and kept warm for 5 h for secondary calcination, and finally cooled to room temperature to obtain an ammonia oxidation catalyst 5#.

[0100] After testing, the active component ratio in the above-mentioned ammonia oxidation catalyst 5# is V 1.0 R 0.1 Ga 0.05 Ag 0.002 Bi 0.05 O 2.0003 55 .

[0101] The ammonia oxidation catalyst 5# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The reaction raw material feed ratio was 1:3.1:12 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 370°C, the reaction pressure (gauge pressure) was 36 kPa, and the catalyst weight load in the reactor was 0.032 h -1 .

[0102] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 99.3% and the selectivity of isophthalonitrile was 99.1%.

[0103] Example 6

[0104] This embodiment provides an ammonia oxidation catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps:

[0105] (1) 66.04 g of oxalic acid was added to 202 g of hot water at 85° C. to form an oxalic acid solution. According to the structural formula of the active component in the ammonia oxidation catalyst, 44.6 g of vanadium pentoxide was first slowly added to the oxalic acid solution, and then 3.43 g of rhodium acetate, 0.283 g of scandium nitrate, 0.0023 g of yttrium nitrate, and 0.0000071 g of 85 wt % phosphoric acid were dissolved in 140 g, 20 g, 20 g, and 10 g of water, respectively, and added to the oxalic acid solution to form a reaction solution A.

[0106] (2) adding the reaction solution B containing the carrier compound to the reaction solution A described in step (1) to form an impregnation mixed solution;

[0107] The preparation method of the reaction solution B comprises the following steps: adding 16.56 g of NaAlO2 to 95 g of water, stirring at room temperature until completely dissolved to form an aluminum source; adding the aluminum source to 303.4 g of silica sol with a mass percentage of 40%, mixing to obtain a first mixed solution, then adding 53.176 g of glycerol to the first mixed solution, mixing to obtain a second mixed solution, and aging at 80° C. for 12 h to obtain the reaction solution B;

[0108] (3) The impregnation mixed solution of step (2) is evaporated and concentrated at 85° C. until a slurry liquid with a solid content of 60% is obtained; the obtained slurry liquid is spray-dried at an inlet temperature of 250° C. and an outlet temperature of 170° C. to obtain a catalyst precursor; the obtained catalyst precursor is placed in a muffle furnace, heated to 140° C. at a heating rate of 2° C. / min and kept warm for 4 h for primary calcination, heated to 630° C. at a heating rate of 2° C. / min and kept warm for 5 h for secondary calcination, and finally cooled to room temperature to obtain an ammonia oxidation catalyst 5#.

[0109] After testing, the active component ratio in the above-mentioned ammonia oxidation catalyst 5# is V 1.0 R 0.05 Sc 0.1 Y 0.005 P 0.01 O 3.98 .

[0110] The ammonia oxidation catalyst 5# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The reaction raw material feed ratio was 1:3.1:12 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 370°C, the reaction pressure (gauge pressure) was 36 kPa, and the catalyst weight load in the reactor was 0.032 h -1 .

[0111] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 99.3% and the selectivity of isophthalonitrile was 99.2%.

[0112] Example 7

[0113] This embodiment provides an ammonia oxidation catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps:

[0114] (1) 66.04 g of oxalic acid was added to 202 g of hot water at 85° C. to form an oxalic acid solution. According to the structural formula of the active component in the ammonia oxidation catalyst, 44.6 g of vanadium pentoxide was first slowly added to the oxalic acid solution. Then, 34.335 g of rhodium acetate, 2.12 g of manganese acetate, 0.208 g of silver nitrate, and 0.018 g of antimony acetate were dissolved in 200 g, 50 g, 10 g, and 10 g of water, respectively, and added to the oxalic acid solution to form a reaction solution A.

[0115] (2) adding the reaction solution B containing the carrier compound to the reaction solution A described in step (1) to form an impregnation mixed solution;

[0116] The preparation method of the reaction solution B comprises the following steps: adding 16.56 g of NaAlO2 to 95 g of water, stirring at room temperature until completely dissolved to form an aluminum source; adding the aluminum source to 303.4 g of silica sol with a mass percentage of 40%, mixing to obtain a first mixed solution, then adding 53.176 g of glycerol to the first mixed solution, mixing to obtain a second mixed solution, and aging at 80° C. for 12 h to obtain the reaction solution B;

[0117] (3) The impregnation mixed solution of step (2) is evaporated and concentrated at 85° C. until a slurry liquid with a solid content of 60% is obtained; the obtained slurry liquid is spray-dried at an inlet temperature of 250° C. and an outlet temperature of 170° C. to obtain a catalyst precursor; the obtained catalyst precursor is placed in a muffle furnace, heated to 140° C. at a heating rate of 2° C. / min and kept warm for 4 h for primary calcination, heated to 630° C. at a heating rate of 2° C. / min and kept warm for 5 h for secondary calcination, and finally cooled to room temperature to obtain an ammonia oxidation catalyst 5#.

[0118] After testing, the active component ratio in the above-mentioned ammonia oxidation catalyst 5# is V 1.0 R 0.5 Mn 0.1 Ag 0.1 Sb 0.05 O 4.16 .

[0119] The ammonia oxidation catalyst 5# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The reaction raw material feed ratio was 1:3.1:12 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 370°C, the reaction pressure (gauge pressure) was 36 kPa, and the catalyst weight load in the reactor was 0.032 h -1 .

[0120] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 99.5% and the selectivity of isophthalonitrile was 99.4%.

[0121] Comparative Example 1

[0122] This comparative example provides an ammonia oxidation catalyst, which is prepared according to the method of Example 1 in patent CN106268890A to obtain a catalyst having a composition of V1Cr1P1B 0.5 Mo 0.1 Co 0.1 K 0.05 W 0.1 Zr 0.02 / 50wt%SiO2 catalyst 1-1#.

[0123] The ammonia oxidation catalyst 1-1# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The reaction raw material feed ratio was 1:3.1:12 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 370°C, the reaction pressure (gauge pressure) was 36 kPa, and the catalyst weight load in the reactor was 0.032 h -1 .

[0124] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 98.1% and the selectivity of isophthalonitrile was 84.3%.

[0125] Comparative Example 2

[0126] This comparative example provides an ammonia oxidation catalyst, which is prepared according to the method of Example 1 in patent CN102218334B to obtain a catalyst having a composition of V1Sb1B 0.5 P 0.05 Mo 0.3 Na 0.05 / SiO2 catalyst 2-1#.

[0127] The ammonia oxidation catalyst 2-1# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The feed ratio of the reaction raw materials was 1:3.5:11 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 365°C, the reaction pressure (gauge pressure) was 27 kPa, and the catalyst weight load in the reactor was 0.04 h -1 .

[0128] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 98.5% and the selectivity of isophthalonitrile was 82.0%.

[0129] Comparative Example 3

[0130] This comparative example provides an ammonia oxidation catalyst, which is prepared according to the method of Example 1 in patent CN106362760A to obtain a catalyst having a composition of V 1.0 Cr 1.1 B 0.5 P 0.8 Nb0.15 Co 0.1 K 0.05 W 0.125 Zr 0.025 / 50wt%SiO2 catalyst 3-1#.

[0131] The ammonia oxidation catalyst 3-1# obtained above was loaded into a laboratory ammonia oxidation fluidized bed reactor for reaction performance evaluation. The reaction raw material feed ratio was 1:2.1:10.1 according to the molar ratio of m-xylene: ammonia: oxygen. The reaction temperature of the ammonia oxidation reactor was 360°C, the reaction pressure (gauge pressure) was 29 kPa, and the catalyst weight load in the reactor was 0.037 h -1 .

[0132] After the reactor was operated for 200 h, the conversion rate of meta-xylene was 98.5% and the selectivity of isophthalonitrile was 87.8%.

[0133] Table 1

[0134]

[0135]

[0136] In summary, the ammonia oxidation catalyst of the present invention belongs to a V-Rh system catalyst. By accurately limiting the stoichiometric ratio of V to Rh in the active component to 1.0:(0.05-5), and limiting the stoichiometric ratios of Class B, Class C and Class D metal elements, it can not only improve product selectivity, reduce the degree of deep oxidation of raw materials, increase raw material conversion rate, and reduce raw material waste, but also has high stability and mechanical strength, and is suitable for large-scale industrial production applications, especially for the application in the preparation of isophthalonitrile by ammoxidation of meta-xylene.

[0137] The applicant declares that the present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An ammonia oxidation catalyst, characterized in that The ammonia oxidation catalyst comprises a carrier and an active component, wherein the silicon-aluminum ratio of the carrier is 1:(0.001-0.1); The active components satisfy the following structural formula calculated by atomic ratio: 1.0 R a B b C c D d O x ; Wherein, B is selected from any one or a combination of at least two of Sc, Mn, Ga or Mo, C is selected from any one or a combination of at least two of Zr, Y or Ag, and D is selected from any one or a combination of at least two of As, Bi, P or Sb; a=0.05~1, b=0.01~2, c=0.001~1, d=0.001~1, x=2.0~9.

0.

2. The ammonia oxidation catalyst according to claim 1, characterized in that In the structural formula V 1.0 R a B b C c D d O x In the equation, a=0.08~1, b=0.05~1, c=0.05~0.8, and d=0.01~0.

5.

3. The ammonia oxidation catalyst according to claim 1, characterized in that Based on the total mass of the ammonia oxidation catalyst, the mass percentage of the active component is 20-70%, and the remainder is the carrier.

4. The ammonia oxidation catalyst according to claim 1, characterized in that The carrier is an MFI structure molecular sieve.

5. The ammonia oxidation catalyst according to claim 1, characterized in that The silicon-aluminum ratio of the carrier is 1:(0.005-0.07).

6. A method for preparing the ammonia oxidation catalyst according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) preparing an aqueous solution containing various metal elements according to the structural formula of the active component in the ammonia oxidation catalyst, and mixing the aqueous solution with an oxalic acid solution to form a reaction solution A; (2) mixing the reaction solution A described in step (1) with the reaction solution B containing the carrier or a compound containing the carrier to form an impregnation mixed solution; (3) sequentially evaporating and concentrating the impregnation mixed solution of step (2), drying and calcining to obtain the ammonia oxidation catalyst; Wherein, the preparation method of reaction solution B in step (2) comprises the following steps: Mixing an aluminum source and a silicon source to obtain a first mixed solution, then mixing the first mixed solution with an auxiliary agent to obtain a second mixed solution, and subjecting the mixture to an aging treatment to obtain the reaction solution B; The silicon-aluminum ratio of the aluminum source to the silicon source is 1:(0.001-0.1).

7. The preparation method according to claim 6, characterized in that: The aluminum source includes sodium metaaluminate and / or aluminum sulfate.

8. The preparation method according to claim 6, characterized in that: The silicon source includes tetraethyl orthosilicate and / or silica sol.

9. The preparation method according to claim 6, characterized in that: The silicon-aluminum ratio of the aluminum source to the silicon source is 1:(0.005-0.07).

10. The preparation method according to claim 6, characterized in that: The auxiliary agent includes any one of glycerol, organic amine or quaternary ammonium salt.

11. The preparation method according to claim 10, characterized in that: The auxiliary agent is glycerol.

12. The preparation method according to claim 6, characterized in that: The molar ratio of the auxiliary agent to the silicon element in the silicon source is 0.1-30.

13. The preparation method according to claim 12, characterized in that: The molar ratio of the auxiliary agent to the silicon element in the silicon source is 0.5-20.

14. The preparation method according to claim 6, characterized in that: The aging treatment time is 6 to 24 hours.

15. The preparation method according to claim 14, characterized in that: The aging treatment time is 8 to 20 hours.

16. The preparation method according to claim 6, characterized in that: The temperature of the aging treatment is 40-120°C.

17. The preparation method according to claim 16, characterized in that: The temperature of the aging treatment is 50-100°C.

18. The preparation method according to claim 6, characterized in that: The temperature of the evaporation concentration in step (3) is 40-100°C.

19. The preparation method according to claim 6, characterized in that: The evaporation and concentration in step (3) obtains a slurry liquid with a solid content of 35-75%.

20. The preparation method according to claim 6, characterized in that: The drying in step (3) is spray drying.

21. The preparation method according to claim 20, characterized in that: The inlet temperature of the spray drying is 180-280°C, and the outlet temperature is 110-180°C.

22. The preparation method according to claim 6, characterized in that: The heating rate of the calcination in step (3) is 1 to 10°C / min.

23. The preparation method according to claim 22, characterized in that: The heating rate of the calcination in step (3) is 2 to 6°C / min.

24. The preparation method according to claim 6, characterized in that: The roasting in step (3) includes primary roasting and secondary roasting.

25. The preparation method according to claim 24, characterized in that: The temperature of the primary calcination is 120-170°C.

26. The preparation method according to claim 25, characterized in that: The temperature of the primary calcination is 120-150°C.

27. The preparation method according to claim 24, characterized in that: The primary calcination time is 3 to 12 hours.

28. The preparation method according to claim 24, characterized in that: The temperature of the secondary calcination is 600-750°C.

29. The preparation method according to claim 28, characterized in that: The temperature of the secondary calcination is 620-700°C.

30. The preparation method according to claim 24, characterized in that: The secondary calcination time is 4 to 10 hours.

31. A method for preparing isophthalonitrile, characterized in that: The method includes the following contents: Using the ammonia oxidation catalyst described in any one of claims 1 to 5, or the ammonia oxidation catalyst obtained by the preparation method described in any one of claims 6 to 30, meta-xylene ammonia and oxygen-containing gas are subjected to an ammonia oxidation reaction under the action of the ammonia oxidation catalyst to obtain isophthalonitrile.

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