Catalyst for ammoxidation reaction, preparation method of catalyst and application of catalyst in preparation of phthalonitrile through xylene gas phase ammoxidation

Abstract

The invention relates to the technical field of chemical engineering, and discloses a catalyst for ammoxidation, a preparation method of the catalyst and application of the catalyst to preparation of phthalonitrile through xylene gas-phase ammoxidation. The catalyst comprises an active component and a carrier, wherein elements of the active component comprise V, Cr and Mn; a CrVO4 crystal phase and an alpha-Mn2O3 crystal phase exist in the catalyst. The selectivity and the yield of the target product of the ammoxidation reaction can be improved.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a catalyst for ammonia oxidation reaction, its preparation method, and its application in the gas-phase ammonia oxidation of xylene to prepare phthalonitrile. Background Technology

[0002] Due to the high reactivity of their cyano groups, aromatic nitriles can be prepared into a variety of organic chemical intermediates through a series of reactions such as addition, hydrolysis, and polymerization, making them play a pivotal role in the field of fine chemicals.

[0003] Aromatic nitrile compounds can be prepared by chemical methods and ammonia oxidation. Compared with chemical synthesis methods, gas-phase ammonia oxidation has advantages such as low cost, atom economy, short steps, high product quality, and environmental friendliness, making it the main production process for synthesizing aromatic nitrile compounds. Phthalonil, one of the aromatic nitrile compounds, is an important organic chemical intermediate with multiple applications: firstly, it is used to synthesize phthalocyanine drugs, phthalocyanine pigments and dyes, high thermal resistance polyamide fibers, xylene, diisocyanate plastics, and desulfurization catalysts; secondly, it is used to synthesize phthalocyanine resins, which are widely used in high-temperature, high-performance fields such as aerospace, automotive manufacturing, and electronic devices; and thirdly, it is used to produce pesticides, fragrances, rubber additives, fungicides, insecticides, and herbicides.

[0004] The methods for synthesizing phthalonitrile can be broadly classified into three categories: First, using phthalimide as a raw material, it reacts with ammonia to obtain phthalamide, which is then dehydrated to obtain phthalonitrile. Second, using naphthalene or o-xylene as a raw material, it undergoes an ammoxidation reaction with ammonia and air to produce phthalonitrile in one step. Third, using haloaromatic hydrocarbons as raw materials, phthalonitrile is obtained under the catalysis of nickel complexes. Among these, the o-xylene gas-phase ammoxidation method is the simplest, most environmentally friendly, and lowest cost. However, this process easily generates byproducts phthalimide and o-methylbenzonitrile during the reaction. Therefore, the key to this process is the development of high-performance catalysts with high conversion rates and good selectivity. To date, the domestic company Qicai Chemical has reported the research status of related catalysts in patent CN112920080A, but this is only at the laboratory research stage, with no reports of pilot-scale or industrial-scale production. Internationally, only a few companies, such as BASF, produce phthalonitrile, but the selectivity and yield are low, with a molar yield of 64.1%-64.2%.

[0005] The mechanism of o-xylene ammoxidation reaction is as follows: Figure 1 As shown, in order to improve the selectivity of the target product phthalonitrile, it is necessary to adjust the microstructure of the active component in the catalyst, reduce its oxidation activity, water adsorption capacity and surface acidity, and at the same time change the reaction conditions so that the byproduct phthalimide can further react with ammonia to obtain phthalamide, and then be dehydrated to obtain phthalonitrile, thereby improving the yield of the target product phthalonitrile. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of low product selectivity and yield in the existing ammonia oxidation reaction, and to provide a catalyst for the ammonia oxidation reaction, its preparation method, and its application in the gas-phase ammonia oxidation of xylene to prepare phthalonitrile. The catalyst of this invention has good stability and long life, and has the advantages of reducing the reaction temperature and having high product selectivity and yield in the ammonia oxidation reaction. It is particularly suitable for the gas-phase ammonia oxidation of xylene to prepare phthalonitrile.

[0007] According to a first aspect of the present invention, the present invention provides a catalyst for ammonia oxidation reaction, the catalyst comprising: an active component and a support; wherein the active component comprises V, Cr, and Mn, and the catalyst contains CrVO4 crystalline phase and α-Mn2O3 crystalline phase.

[0008] According to a second aspect of the present invention, the present invention provides a method for preparing the catalyst of the present invention, the method comprising: impregnating and contacting an active component source solution with a support, and calcining the solid obtained by contact.

[0009] According to a third aspect of the present invention, the present invention provides the application of the catalyst described herein in the gas-phase ammoxidation of xylene to prepare phthalonitrile.

[0010] The catalyst for ammonia oxidation provided by this invention has the advantages of good stability and long lifespan. At the same time, it can reduce the temperature of ammonia oxidation reaction and improve the selectivity and yield of the target product of ammonia oxidation reaction. It is particularly suitable for the gas-phase ammonia oxidation of xylene to prepare phthalonitrile. Attached Figure Description

[0011] Figure 1 Diagram of the ammoxidation mechanism of o-xylene;

[0012] Figure 2 This is the XRD pattern of the catalyst in Example 1;

[0013] Figure 3 This is the XRD pattern of the catalyst in Comparative Example 1. Detailed Implementation

[0014] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention. The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] This invention provides a catalyst for ammonia oxidation, comprising an active component and a support, wherein the active component includes V, Cr, and Mn, and the catalyst contains CrVO4 and α-Mn2O3 crystalline phases. The catalyst with the aforementioned technical characteristics has the advantages of good stability and long lifespan, while also reducing the ammonia oxidation reaction temperature, and has significant advantages in improving the selectivity and yield of the target product in the ammonia oxidation reaction.

[0016] In this invention, the content ratio of V, Cr, and Mn elements can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the molar ratio of V to Cr is 1:0.6-2.5.

[0017] According to a preferred embodiment of the present invention, the molar ratio of V to Mn is 1:0.01-1.

[0018] According to a preferred embodiment of the present invention, the XRD pattern of the catalyst of the present invention has characteristic peaks at 2θ positions of 13.8 (±0.3)°, 23.7 (±0.3)°, 27.8 (±0.3)°, 28.4 (±0.3)°, 32.3 (±0.3)°, 33.4 (±0.3)°, 34.9 (±0.3)°, 35.6 (±0.3)°, 40.6 (±0.3)°, 42.3 (±0.3)°, 48.9 (±0.3)°, 53.2 (±0.3)°, 56.2 (±0.3)°, 62.3 (±0.3)°, and 64.2 (±0.3)°. These peak positions include characteristic peaks of the CrVO4 crystal phase and the α-Mn2O3 crystal phase.

[0019] According to a preferred embodiment of the present invention, the active component of the catalyst further contains phosphorus (P).

[0020] In this invention, the content of element P can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the molar ratio of V to P is 1:0.01-0.5, preferably 1:0.01-0.3.

[0021] According to a preferred embodiment of the present invention, the active component of the catalyst further contains element B.

[0022] In this invention, the content of element B can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the molar ratio of V to B is 1:0.01-0.5, preferably 1:0.01-0.3.

[0023] Catalysts with the aforementioned technical characteristics have the advantages of uniform distribution of active components, moderate surface acidity, higher product selectivity, and higher yield.

[0024] According to a preferred embodiment of the present invention, the active component of the catalyst further contains α element and / or β element, preferably, it contains both α element and β element.

[0025] In this invention, the range of α elements that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the α element is selected from one or more of Fe, Nb, Bi, Sb, Co, Mo, and W.

[0026] In this invention, the content of element α can be selected within a wide range, as illustrated below, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the molar ratio of V to α is 1:0.01-0.2.

[0027] In this invention, the range of possible β elements is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the β element is selected from one or more elements of Group IA and Group IIA.

[0028] In this invention, the content of element β can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the molar ratio of V to β is 1:0.01-0.3, preferably 1:0.01-0.15.

[0029] Catalysts with the aforementioned technical features can further improve the selectivity and yield of target products in ammonia oxidation reactions.

[0030] In this invention, there are no special requirements for the type of support; commonly used types can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the support is Fe-doped TiO2, i.e., Fe-TiO2. This invention has found that the Fe-TiO2 support can prevent the target product from hydrolyzing on the catalyst surface, thereby improving the selectivity and yield of the target product.

[0031] In this invention, the Fe content in the Fe-TiO2 support can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the molar ratio of Fe to Ti in the Fe-TiO2 support is 0.01-0.1:1.

[0032] In this invention, the type of TiO2 in the Fe-TiO2 support is not particularly required; commonly used types can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the TiO2 is selected from one or more of brookite TiO2, rutile TiO2, and anatase TiO2, preferably brookite TiO2.

[0033] In this invention, the content of the carrier can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the molar ratio of V to the mass of the carrier is 1 mol: 20-60 g.

[0034] Catalysts for ammonia oxidation reactions possessing the aforementioned characteristics can achieve the objectives of this invention. There are no special requirements for their preparation methods; the following is an illustrative description, but it does not limit the scope of the invention. According to one embodiment of the invention, the catalyst preparation method includes: impregnating and contacting an active component source solution with a support, and calcining the resulting solid.

[0035] In this invention, the method of impregnation contact is not particularly required; commonly used methods can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the method of impregnation contact is equal-volume impregnation.

[0036] In this invention, the preparation method allows for a wide range of possible temperatures for the impregnation contact. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the impregnation contact temperature is 70-100°C.

[0037] In this invention, the preparation method allows for a wide range of possible immersion contact times, as illustrated below but not limiting the scope of the invention. According to a preferred embodiment of the invention, the immersion contact time is 1-4 hours, preferably 2-3 hours.

[0038] In this invention, the calcination temperature can be selected within a wide range in the preparation method. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the calcination temperature is 300-650°C, preferably 500-650°C.

[0039] In this invention, the calcination time in the preparation method can be selected and adjusted according to the temperature. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the calcination time is 3-15 hours, preferably 8-10 hours.

[0040] According to a preferred embodiment of the present invention, in the preparation method, the active component source solution contains a polymeric material additive, wherein the polymeric material additive is selected from at least two of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and polyacrylamide (PAM).

[0041] In this invention, the number-average molecular weight of the polyvinyl alcohol can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the number-average molecular weight of the polyvinyl alcohol is 25,000-150,000.

[0042] In this invention, the number-average molecular weight of the polyvinylpyrrolidone can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the number-average molecular weight of the polyvinylpyrrolidone is 160,000-360,000.

[0043] In this invention, the number-average molecular weight of the polyacrylamide can be selected from a wide range, as illustrated below, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the number-average molecular weight of the polyacrylamide is ≥3,000,000.

[0044] In this invention, the dosage of each polymeric material additive can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the content of any one of the polymeric material additives is not less than 25 wt% based on the total amount of the polymeric material additives.

[0045] In this invention, the amount of polymeric material additive can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, V is calculated as V₂O₅, and the mass ratio of V to polymeric material additive is 1:0.5-1.5.

[0046] The active component source solution containing polymeric material additives with the aforementioned characteristics can reduce the calcination temperature and shorten the calcination time, and the prepared catalyst has higher product selectivity and yield, as well as better catalyst stability and lifespan.

[0047] In this invention, when the active component source solution contains polymeric material additives, the calcination temperature range in the preparation method is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, when the active component source solution contains polymeric material additives, the calcination temperature is 300-450°C.

[0048] In this invention, when the active component source solution contains polymeric material additives, the calcination time in the preparation method can be adjusted according to the temperature. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, when the active component source solution contains polymeric material additives, the calcination time is 3-6 hours.

[0049] In this invention, obtaining the source solution of the active component is not the focus. The source solution of the active component is prepared according to the required catalyst composition and the proportions of each component are prepared. The source solution required for impregnation in the prior art is dissolved and mixed. For example, each active component raw material can be dissolved to form the solution. Depending on the solubility of the specific raw material, a dissolving aid can be added. For example, oxalic acid is added to dissolve the vanadium source.

[0050] In this invention, the catalyst composition is calculated based on the feed amount. Therefore, the active component source solution can be prepared according to the target composition. For example, when the active component also contains P and / or B elements, the molar ratio of V to P in the active component source solution is preferably 1:0.01-0.5, more preferably 1:0.01-0.3; the molar ratio of V to B is 1:0.01-0.5, more preferably 1:0.01-0.3.

[0051] For example, the active component also contains α and / or β elements. Preferably, when both α and β elements are present, the α element is selected from one or more of Fe, Nb, Bi, Sb, Co, Mo, and W; the β element is selected from one or more of Group IA and Group IIA elements. Preferably, in the active component source solution, the molar ratio of V to α is 1:0.01-0.2; the molar ratio of V to β is 1:0.01-0.3, and more preferably 1:0.01-0.15.

[0052] In this invention, the polymer material additive can be added to the active component source solution as long as it is in the solution, and there are no special requirements for the order of introduction. For example, each active component raw material can be dissolved and then added to the polymer material additive.

[0053] According to one embodiment of the present invention, the active component source solution is prepared as follows: a vanadium source is dissolved in an oxalic acid solution to obtain a vanadium-containing solution, then a chromium source, a manganese source and other auxiliary raw materials are dissolved and added to the vanadium-containing solution and heated and stirred, and finally at least two of the polymer material additives polyvinyl alcohol, polyvinylpyrrolidone and polyacrylamide are added to the above solution to finally obtain the active component source solution.

[0054] In this invention, any Fe-TiO2 support possessing the aforementioned characteristics can achieve the objectives of this invention. There are no special requirements for its preparation method; the following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the preparation method of the Fe-TiO2 support includes: dissolving a titanium source in a mixed solution of oleic acid and ferric oleate, and then thermally contacting it with a mixed solution of oleylamine and octadecene to obtain the Fe-TiO2 support.

[0055] In this invention, the type of titanium source used in the preparation method of the Fe-TiO2 support is not particularly required; commonly used types can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the titanium source is selected from one or more of TiCl3, TiCl4, and Ti(SO4)2.

[0056] In this invention, the mass ratio of oleic acid, ferric oleate, oleylamine, and octadecene in the preparation method of the Fe-TiO2 support can be selected within a wide range. The following is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of oleic acid, ferric oleate, oleylamine, and octadecene is 4.3-12.7:1:4-11:3-10.6, thereby obtaining the support described in this invention, for example, the support described above in this invention.

[0057] In this invention, the thermal contact temperature range in the preparation method of the Fe-TiO2 support is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the contact temperature is 280-300°C.

[0058] In this invention, the thermal contact time in the preparation method of the Fe-TiO2 support can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of the invention, the contact time is 10-15 hours, preferably 12-14 hours.

[0059] This invention provides the application of the catalyst described herein for the ammonia oxidation reaction in the gas-phase ammonia oxidation of xylene to prepare phthalonitrile.

[0060] In this invention, any catalyst possessing the aforementioned technical characteristics can achieve the objective of this invention when applied to the gas-phase ammoxidation of xylene to prepare phthalonitrile. There are no special requirements for its application method. The following is an illustrative description of the application method of the catalyst in the gas-phase ammoxidation of xylene to prepare phthalonitrile, but this does not limit the scope of the invention. For example, phthalonitrile can be prepared using xylene, ammonia, and oxygen-containing gas as raw materials in the presence of the catalyst, with a raw material molar ratio of xylene:ammonia:oxygen = 1:15-30:1.6-5.

[0061] In this invention, the range of selectable catalyst mass hourly space velocity (MHV) in the application method is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the MHV of xylene is 0.06-0.08 h⁻¹. -1 .

[0062] In this invention, the temperature range for preparing phthalonitrile is relatively wide, as illustrated below, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the temperature is 450-520°C.

[0063] In this invention, the pressure range for preparing phthalonitrile is relatively wide, as illustrated below, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the pressure is atmospheric pressure.

[0064] In this invention, the reactor used for preparing phthalonitrile in the application method has no special requirements; any commonly used reactor can achieve the purpose of this invention, such as preparing phthalonitrile in a fixed-bed reactor.

[0065] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

[0066] The present invention will be described in detail below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0067] For any experimental steps or conditions not specified in the examples and comparative examples, the procedures and conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0068] A. Sources of raw materials for the examples and comparative examples

[0069] The chemical raw materials used in the examples and comparative examples were all from Sinopharm Reagent, and their purity was analytical grade.

[0070] The number average molecular weight of polyvinyl alcohol is 100,000; the number average molecular weight of polyvinylpyrrolidone is 200,000; and the number average molecular weight of polyacrylamide is 3,500,000.

[0071] BX-ray diffraction (XRD) test

[0072] The catalyst samples were subjected to XRD tests using a Bruker D8 X-ray powder diffractometer (Germany) to characterize their crystal structure. A Cu-Kα X-ray source (Kα1 wavelength λ = 1.5405980 Å) and a nickel filter were used. The operating voltage was 40 kV, the current was 40 mA, and the scanning range was 2θ 5°–80°.

[0073] C. Evaluation of the catalytic effect in the gas-phase ammoxidation of xylene to prepare phthalonitrile

[0074]

[0075]

[0076] Example 1

[0077] Carrier preparation:

[0078] 118.7 g TiCl4 was dissolved in a mixed solution of 176.8 g oleic acid and 28.2 g ferric oleate. After stirring evenly, the resulting solution was added to a mixed solution of 167.5 g oleylamine and 158.1 g octadecene. The mixture was stirred at 290 °C for 12 h, filtered, and the resulting solid was dried to obtain Fe-TiO2 support. The TiO2 was of the brookite type.

[0079] Catalyst preparation:

[0080] Add 14g of V₂O₅ to 60mL of water containing 14.1g of oxalic acid monohydrate, preheated to 85℃, and stir thoroughly to obtain a blue solution. Add 61.6g of Cr(NO₃)₃·9H₂O, 11.6g of Mn(NO₃)₂·4H₂O, 0.015mol of phosphoric acid, and 1.4g of (NH₄)₆Mo₇O₇. 24·4H₂O and 1.6g KNO₃ were dissolved in water and added to a blue solution. The mixture was stirred at 90℃ for 3 hours to obtain an active component source solution. Then, 5g Fe-TiO₂ support was added to the active component source solution and impregnated at 90℃ with an equal volume. The mixture was filtered, and the resulting solid was dried. The solid was calcined at 600℃ for 8 hours to obtain the catalyst.

[0081] The catalyst has the composition VCrMn 0.3 P 0.1 Mo 0.05 K 0.1 O x / Fe-TiO2, where the value of x satisfies valence equilibrium. The x values ​​in the following examples and comparative examples all satisfy this requirement, and will not be elaborated further. The XRD pattern of the catalyst is shown below. Figure 2 As shown, at 2θ values ​​of 13.8(±0.3)°, 23.7(±0.3)°, 27.8(±0.3)°, 28.4(±0.3)°, 32.3(±0.3)°, 33.4(±0.3)°, 34.9(±0.3)°, and 35.6(±0.3)°...

[0082] °, 40.6 (±0.3)°, 42.3 (±0.3)°, 48.9 (±0.3)°, 53.2 (±0.3)°, 56.2 (±0.3)°

[0083] Characteristic peaks exist at 62.3°, 62.3° (±0.3)°, and 64.2° (±0.3)°, including the main diffraction characteristic peaks of the obvious CrVO4 crystal phase and α-Mn2O3 crystal phase. The XRD patterns of the catalysts in the following examples are similar to those in Example 1, and will not be repeated.

[0084] application:

[0085] 5g of catalyst was loaded into a fixed-bed reactor with a feed molar ratio of o-xylene:NH3:O2 = 1:20:3 and a catalyst mass hourly space velocity (based on o-xylene) of 0.06 h⁻¹. -1 The reaction temperature was 420℃, and the pressure was atmospheric pressure. After 10 hours of reaction, the conversion rate of o-xylene was 99.8%, the selectivity of phthalonitrile was 95.6%, and the yield of phthalonitrile was 95.4%. After 200 hours of reaction, the conversion rate of o-xylene was 80.1%, the selectivity of phthalonitrile was 81.2%, and the yield of phthalonitrile was 65.0%.

[0086] Example 2

[0087] The method of Example 1 was followed, except that ferric oleate was not added during the preparation of the support, and the resulting support was a TiO2 support. The composition of the obtained catalyst was VCrMn. 0.3 P 0.1 Mo 0.05 K0.1 O x / TiO2. After reacting for 10 h, the conversion rate of o-xylene was 99.5%; the selectivity of phthalonitrile was 95.1%; and the yield of phthalonitrile was 94.6%.

[0088] Example 3

[0089] The method is the same as in Example 1, except that 1.4 g of (NH4)6Mo7O was used in the catalyst preparation. 24 ·4H₂O and 1.6g KNO₃ were replaced with 4.7g potassium antimony tartrate. The resulting catalyst had the composition VCrMn. 0.3 P 0.1 Sb 0.1 K 0.1 O x / Fe-TiO2. After 10 h of reaction, the conversion rate of o-xylene was 99.3%; the selectivity of phthalonitrile was 93.4%; and the yield of phthalonitrile was 92.7%.

[0090] Example 4

[0091] The method is the same as in Example 1, except that 1.4 g of (NH4)6Mo7O was used in the catalyst preparation. 24 ·4H₂O was replaced with 8.3 g of niobium oxalate. The resulting catalyst had the composition VCrMn. 0.3 P 0.1 Nb 0.1 K 0.1 O x / Fe-TiO2. After reacting for 10 h, the conversion rate of o-xylene was 98.9%; the selectivity of phthalonitrile was 93.1%; and the yield of phthalonitrile was 92.1%.

[0092] Example 5

[0093] The method is the same as in Example 1, except that 1.4 g of (NH4)6Mo7O was used in the catalyst preparation. 24 ·4H2O was replaced with 7.5g Bi(NO3)3·5H2O. The resulting catalyst had the composition VCrMn. 0.3 P 0.1 Bi 0.1 K 0.1 O x / Fe-TiO2. After reacting for 10 h, the conversion rate of o-xylene was 99.8%; the selectivity of phthalonitrile was 93.6%; and the yield of phthalonitrile was 93.4%.

[0094] Example 6

[0095] The method of Example 1 was followed, except that 1.6 g of KNO3 was replaced with 2.35 g of Mg(NO3)2 in the catalyst preparation. The resulting catalyst had the composition VCrMn. 0.3 P 0.1 Mo 0.05 Mg 0.1 O x / Fe-TiO2. After reacting for 10 h, the conversion rate of o-xylene was 98.6%; the selectivity of phthalonitrile was 93.1%; and the yield of phthalonitrile was 91.8%.

[0096] Example 7

[0097] The method was the same as in Example 1, except that the mass of ferric oleate in the support preparation was 16.9 g. The amounts of Cr(NO3)3·9H2O, Mn(NO3)2·4H2O, phosphoric acid, and (NH4)6Mo7O added during catalyst preparation were 154 g, 19.3 g, 0.03 mol, and [other components not specified in the original text]. 24 The amount of 4H2O added was 5.6 g, and the amount of KNO3 added was 2.4 g. The resulting catalyst composition was VCr. 2.5 Mn 0.5 P 0.2 Mo 0.2 K 0.15 O x / Fe-TiO2. After reacting for 10 h, the conversion rate of o-xylene was 98.2%; the selectivity of phthalonitrile was 92.1%; and the yield of phthalonitrile was 90.4%.

[0098] Example 8

[0099] The method was the same as in Example 1, except that 0.075 mol of phosphoric acid and 4.8 g of KNO3 were added during catalyst preparation, and (NH4)6Mo7O was not added. 24 ·4H₂O. The resulting catalyst has the composition VCrMn. 0.3 P 0.5 K 0.3 O x / Fe-TiO2. After reacting for 10 h, the conversion rate of o-xylene was 98.1%; the selectivity of phthalonitrile was 91.1%; and the yield of phthalonitrile was 89.4%.

[0100] Example 9

[0101] The method was followed in Example 1, except that the amount of Cr(NO3)3·9H2O added during catalyst preparation was 184.8 g and the amount of Mn(NO3)2·4H2O added was 58 g. The resulting catalyst had the composition VCr3Mn. 1.5 P 0.1 Mo0.05 K 0.1 O x / Fe-TiO2. After 10 h of reaction, the conversion rate of o-xylene was 97.6%; the selectivity of phthalonitrile was 90.4%; and the yield of phthalonitrile was 88.2%.

[0102] Example 10

[0103] The method of Example 1 was followed, except that phosphoric acid was not added during catalyst preparation. The resulting catalyst had the composition VCrMn. 0.3 Mo 0.05 K 0.1 O x / Fe-TiO2. After reacting for 10 h, the xylene conversion rate was 97.8%; the phthalonitrile selectivity was 90.7%; and the phthalonitrile yield was 88.7%.

[0104] Example 11

[0105] The method is the same as in Example 1, except that (NH4)6Mo7O is not added during catalyst preparation. 24 The catalyst obtained from 4H₂O and KNO₃ has the composition VCrMn. 0.3 P 0.1 O x / Fe-TiO2. After reacting for 10 h, the conversion rate of o-xylene was 97.1%; the selectivity of phthalonitrile was 90.2%; and the yield of phthalonitrile was 87.6%.

[0106] Example 12

[0107] The method was followed as in Example 1, except that the calcination temperature was 550°C and the calcination time was 10 h during catalyst preparation. The o-xylene conversion rate was 99.6%; the phthalonitrile selectivity was 95.3%; and the phthalonitrile yield was 94.9%.

[0108] Example 13

[0109] The method is the same as in Example 1, except that the ratio of o-xylene:ammonia:oxygen is 1:32:6, and the catalyst mass hourly space velocity (based on o-xylene) is 1 h⁻¹. -1 The reaction temperature was 480℃. After 10 hours of reaction, the conversion rate of o-xylene was 99.1%; the selectivity of phthalonitrile was 94.8%; and the yield of phthalonitrile was 93.9%.

[0110] Example 14

[0111] The method of Example 1 was followed, except that o-xylene was replaced with m-xylene, with a m-xylene:NH3:O2 ratio of 1:20:3. After reacting for 10 hours, the conversion rate of m-xylene was 99.5%; the selectivity of isophthalonitrile was 95.8%; and the yield of isophthalonitrile was 95.3%.

[0112] Example 15

[0113] The method was followed as in Example 1, except that the active ingredient source also included 0.95 g of boric acid. After reacting for 10 h, the o-xylene conversion was 99.8%; the phthalonitrile selectivity was 96.7%; and the phthalonitrile yield was 96.5%.

[0114] Example 16

[0115] The method was followed as in Example 1, except that the active component source solution also contained 8g of polyvinyl alcohol and 8g of polyvinylpyrrolidone. The catalyst preparation involved calcination at 420°C for 5 hours. After 10 hours of reaction, the o-xylene conversion was 99.7%, the phthalonitrile selectivity was 95.8%, and the phthalonitrile yield was 95.5%. After 200 hours of reaction, the o-xylene conversion was 90.1%, the phthalonitrile selectivity was 87.2%, and the phthalonitrile yield was 78.6%.

[0116] Example 17

[0117] The method was followed as in Example 1, except that the active component source solution also contained 10 g of polyvinyl alcohol and 10 g of polyacrylamide. The catalyst preparation involved calcination at 420 °C for 5 h. After 10 h of reaction, the o-xylene conversion was 99.8%, the phthalonitrile selectivity was 95.8%, and the phthalonitrile yield was 95.6%. After 200 h of reaction, the o-xylene conversion was 89.4%, the phthalonitrile selectivity was 89.2%, and the phthalonitrile yield was 79.7%.

[0118] As can be seen from the results of the above embodiments, the catalyst of the present invention can achieve high conversion rate and selectivity at lower temperatures.

[0119] Comparative Example 1

[0120] The method of Example 5 was followed, except that the support was SiO2 and Mn(NO3)2·4H2O was not added during catalyst preparation, resulting in a catalyst with the composition VCrP. 0.1 Bi 0.1 K 0.1 O x / SiO2, its XRD pattern is as follows Figure 3As shown. At a reaction temperature of 480℃ and a reaction time of 10 h, the o-xylene conversion was 98.8%; the phthalonitrile selectivity was 85.3%; and the phthalonitrile yield was 84.3%. After a reaction time of 200 h, the o-xylene conversion was 76.2%; the phthalonitrile selectivity was 75.1%; and the phthalonitrile yield was 57.2%.

[0121] Comparative Example 2

[0122] The method of Example 13 was followed, except that V₂O₅ was not added during catalyst preparation. The resulting catalyst had the composition CrMn. 0.3 P 0.1 Mo 0.05 K 0.1 O x / Fe-TiO2. At a reaction temperature of 480℃ and a reaction time of 10 h, the o-xylene conversion was 95.2%; the phthalonitrile selectivity was 83.6%; and the phthalonitrile yield was 79.6%. After a reaction time of 200 h, the o-xylene conversion was 75.4%; the phthalonitrile selectivity was 72.3%; and the phthalonitrile yield was 54.5%.

[0123] Comparative Example 3

[0124] The method of Example 13 was followed, except that Cr(NO3)3·9H2O was not added during catalyst preparation. The resulting catalyst had the composition VMn. 0.3 P 0.1 Mo 0.05 K 0.1 O x / Fe-TiO2. At a reaction temperature of 480℃ and a reaction time of 10 h, the o-xylene conversion was 98.5%; the phthalonitrile selectivity was 84.9%; and the phthalonitrile yield was 83.6%. After a reaction time of 200 h, the o-xylene conversion was 76.3%; the phthalonitrile selectivity was 74.8%; and the phthalonitrile yield was 57.1%.

[0125] Comparative Example 4

[0126] The method of Example 13 was followed, except that the calcination temperature was 450°C and the time was 5 h in the catalyst preparation. The XRD pattern of the catalyst did not show CrVO4 or α-Mn2O3 crystal phases. At a reaction temperature of 480°C and a reaction time of 10 h, the o-xylene conversion was 94.1%; the phthalonitrile selectivity was 78.9%; and the phthalonitrile yield was 74.2%. After a reaction time of 200 h, the o-xylene conversion was 75.2%; the phthalonitrile selectivity was 71.6%; and the phthalonitrile yield was 53.8%.

[0127] Comparative Example 5

[0128] The method of Example 13 was followed, except that the calcination temperature was 680°C and the time was 15 h in the catalyst preparation. The XRD pattern of the catalyst did not show CrVO4 or α-Mn2O3 crystal phases. At a reaction temperature of 480°C and a reaction time of 10 h, the o-xylene conversion was 96.1%; the phthalonitrile selectivity was 81.2%; and the phthalonitrile yield was 78.0%. After a reaction time of 200 h, the o-xylene conversion was 75.8%; the phthalonitrile selectivity was 73.7%; and the phthalonitrile yield was 55.9%.

[0129] Comparative Example 6

[0130] The method of Example 16 was followed, except that polyvinyl alcohol and polyvinylpyrrolidone were not added to the active component source solution. The XRD pattern of the catalyst did not show CrVO4 or α-Mn2O3 crystal phases. After 10 h of reaction, the o-xylene conversion was 94.2%; the phthalonitrile selectivity was 76.2%; and the phthalonitrile yield was 71.8%. After 200 h of reaction, the o-xylene conversion was 75.0%; the phthalonitrile selectivity was 70.3%; and the phthalonitrile yield was 52.7%.

Claims

1. A catalyst for ammonia oxidation reaction, characterized in that, The catalyst comprises: an active component and a support, wherein the active component includes V, Cr, and Mn; The catalyst contains CrVO4 and α-Mn2O3 crystal phases.

2. The catalyst according to claim 1, wherein, The molar ratio of V to Cr is 1:0.6-2.5; and / or The molar ratio of V to Mn is 1:0.01-1; and / or The XRD pattern of the catalyst exhibits characteristic peaks at 2θ positions of 13.8 (±0.3)°, 23.7 (±0.3)°, 27.8 (±0.3)°, 28.4 (±0.3)°, 32.3 (±0.3)°, 33.4 (±0.3)°, 34.9 (±0.3)°, 35.6 (±0.3)°, 40.6 (±0.3)°, 42.3 (±0.3)°, 48.9 (±0.3)°, 53.2 (±0.3)°, 56.2 (±0.3)°, 62.3 (±0.3)°, and 64.2 (±0.3)°.

3. The catalyst of claim 1 or 2, wherein, The active ingredient also contains P and / or B elements; Preferably, The molar ratio of V to P is 1:0.01-0.5, preferably 1:0.01-0.3; and / or The molar ratio of V to B is 1:0.01-0.5, preferably 1:0.01-0.

3.

4. The catalyst of any one of claims 1-3, wherein, The active component also contains α and / or β elements, preferably, it contains both α and β elements. in, The α element is selected from one or more of Fe, Nb, Bi, Sb, Co, Mo, and W; and / or The β element is selected from one or more elements in Group IA and Group IIA; Preferably, The molar ratio of V to α is 1:0.01-0.2; and / or The molar ratio of V to β is 1:0.01-0.3, preferably 1:0.01-0.

15.

5. The catalyst of any one of claims 1-4, wherein, The support is Fe-doped TiO2; Preferably, In Fe-doped TiO2, the molar ratio of Fe to Ti is 0.01-0.1:1; and / or The TiO2 is selected from one or more of brookite TiO2, rutile TiO2 and anatase TiO2, and more preferably brookite TiO2.

6. The catalyst of any one of claims 1-5, wherein, The molar ratio of V to the mass of the carrier is 1 mol: 20-60 g.

7. A method for producing the catalyst for an ammoxidation reaction according to any one of claims 1 to 6, characterized by, The method includes: impregnating and contacting the active component source solution with a carrier, and calcining the solid obtained from the contact.

8. The preparation method according to claim 7, wherein, Conditions for immersion contact include: Using equal-volume impregnation; and / or Temperature is 70-100℃; and / or The time is 1-4 hours, preferably 2-3 hours; and / or In the active component source solution, the molar ratio of V to Cr is 1:0.6-2.5; and / or In the active component source solution, the molar ratio of V to Mn is 1:0.01-1; and / or Preferably, In the active component source solution, the molar ratio of V to P is 1:0.01-0.5, preferably 1:0.01-0.3; and / or In the active component source solution, the molar ratio of V to B is 1:0.01-0.5, preferably 1:0.01-0.3; and / or In the active component source solution, the molar ratio of V to α is 1:0.01-0.2, and the α element is selected from one or more of Fe, Nb, Bi, Sb, Co, Mo, and W; and / or In the active component source solution, the molar ratio of V to β is 1:0.01-0.3, preferably 1:0.01-0.15, and the β element is selected from one or more elements of Group IA and Group IIA. and / or The conditions for roasting include: The temperature is 300-650℃, preferably 500-650℃; and / or The time is 3-15 hours, preferably 8-10 hours; and / or The active component source solution contains a polymeric material additive, wherein the polymeric material additive is selected from at least two of polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide; Preferably, The number average molecular weight of the polyvinyl alcohol is 25,000-150,000; and / or The polyvinylpyrrolidone has a number-average molecular weight of 160,000-360,000; and / or The polyacrylamide has a number-average molecular weight of ≥3,000,000; and / or Based on the total amount of polymer material additives used, the content of any one of them shall not be less than 25 wt%; and / or V, calculated as V₂O₅, has a mass ratio of V to polymer additives of 1:0.5-1.5; and / or When the active component source solution contains polymeric material additives, the calcination conditions include: Temperature 300-450℃; and / or The time is 3-6 hours.

9. The production method according to claim 7 or 8, wherein, The preparation method of Fe-doped TiO2 includes: dissolving a titanium source in a mixed solution of oleic acid and iron oleate, and then thermally contacting it with a mixed solution of oleylamine and octadecene to obtain Fe-doped TiO2. Preferably, The titanium source is selected from one or more of TiCl3, TiCl4, and Ti(SO4)2; and / or The mass ratio of oleic acid, ferric oleate, oleylamine, and octadecene is 4.3-12.7:1:4-11:3-10.6; and / or Conditions for thermal contact include: Temperature is 280-300℃; and / or The time is 10-15 hours, preferably 12-14 hours.

10. The use of the catalyst for ammonia oxidation reaction according to any one of claims 1-6 in the gas-phase ammonia oxidation of xylene to prepare phthalonitrile; Preferably, the applying step comprises: Benzene dinitrile was prepared using xylene, ammonia, and oxygen-containing gas as raw materials in the presence of the catalyst. The molar ratio of the raw materials was xylene: ammonia: oxygen = 1:15-30:1.6-5. More preferably, the preparation conditions include: The mass space velocity of the xylene was 0.06-0.08 h -1 ; and / or Temperature is 450-520℃; and / or The pressure is atmospheric pressure; and / or The reactor is a fixed-bed reactor.

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