Ammonia oxidation catalyst, method for producing the same, and method for coproducing m-tolunitrile and m-phthalonitrile by gas-phase ammonia oxidation of m-xylene

Abstract

The present application relates to a kind of ammonia oxidation catalyst and its preparation method and m-xylene gas phase ammonia oxidation coproduction m-methylbenzonitrile and m-phenyldicyanide method.The catalyst includes carrier and active component, active component element includes: vanadium, bismuth and boron, the active component includes BiVO4 Crystal, and the ratio of the intensity of main diffraction characteristic peak attributed to V2O5 And / or Bi2O3 With the intensity of main diffraction characteristic peak attributed to BiVO4 In the XRD spectrum of the catalyst, it is 0-0.15:1.The catalyst has the characteristics of being able to realize the coproduction of m-alkylbenzonitrile and m-phenylalkylnitrile, and high activity and high selectivity.

Description

Technical Field

[0001] This invention relates to an ammonia oxidation catalyst and its preparation method, as well as a method for the gas-phase ammonia oxidation of m-xylene to co-produce m-methylbenzonitrile and m-phthalonitrile. Background Technology

[0002] Aromatic nitriles, due to the high reactivity of their cyano groups, can be prepared into a variety of organic chemical intermediates through a series of reactions such as addition, hydrolysis, and polymerization, giving them a crucial position in the fine chemical industry. m-Toluenebenzonitrile can be used to synthesize m-toluic acid and m-cyanobenzyl chloride, which can then be used to produce dyes and fluorescent agents. Isophthalonitrile can be chlorinated to produce chlorothalonil for pesticide production; it can also be hydrogenated to obtain m-phenylenediamine, which can then be used to produce specialty nylon MXD6, etc.

[0003] Aromatic nitriles can be prepared by chemical methods and ammoxidation. Compared with chemical synthesis, ammoxidation offers advantages such as lower cost, atom economy, shorter steps, higher product quality, and environmental friendliness, making it the main production process for aromatic nitrile compounds. However, this process places high demands on catalyst performance. Vanadium-based catalysts are currently the most mature catalysts used in the ammoxidation of aromatics. However, pure vanadium oxides are too reactive and prone to deep oxidation. Current research mainly focuses on V-Cr, V-Mo, VP, and V-Ce catalyst systems, primarily used for the production of isophthalonitrile, with lower selectivity for m-methylbenzonitrile.

[0004] To improve the selectivity of m-methylbenzonitrile, the composition of the catalyst needs to be adjusted to reduce its oxidation activity and surface acidity. At the same time, the reaction conditions need to be changed so that one of the methyl groups of m-xylene is nitrified and desorbed from the catalyst surface in a timely manner to prevent further conversion to isophthalonitrile, thereby obtaining a higher yield of m-methylbenzonitrile product. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem that existing technologies cannot effectively co-produce m-alkylbenzonitrile and m-phenylalkylnitrile, and to provide an ammonia oxidation catalyst, its preparation method, and a method for co-producing m-methylbenzonitrile and m-phenylenedionitrile by gas-phase ammonia oxidation of m-xylene. This catalyst has the characteristics of being able to achieve the co-production of m-alkylbenzonitrile and m-phenylalkylnitrile, and having high activity and high selectivity.

[0006] To achieve the above objectives, the first aspect of the present invention provides an ammonia oxidation catalyst, the catalyst comprising a support and an active component, the active component comprising vanadium, bismuth and boron, the active component comprising BiVO4 crystals, and the ratio of the intensity of the main diffraction characteristic peaks attributable to V2O5 and / or Bi2O3 to the intensity of the main diffraction characteristic peaks attributable to BiVO4 in the XRD pattern of the catalyst being 0 to 0.15:1.

[0007] A second aspect of the present invention provides a method for preparing the catalyst described in the first aspect, the method comprising:

[0008] (1) Mix the vanadium source, reducing agent and first solvent to prepare solution A;

[0009] (2) First, add boron source and organic acid additive to the second solvent, then add bismuth source to the second mixture to obtain solution B;

[0010] (3) After mixing solution A and solution B, add optional source X and optional source Y to dissolve the prepared solution, and then add it to the carrier source to obtain mixed slurry L;

[0011] (4) The mixed slurry L is heated and concentrated to prepare a slurry;

[0012] (5) The slurry obtained in step (4) is spray-dried and shaped, and then calcined to obtain the catalyst.

[0013] A third aspect of the present invention provides a method for the gas-phase ammonia oxidation of m-xylene to co-produce m-methylbenzonitrile and m-phthalonitrile, using the catalyst described in the first aspect, the method comprising: contacting an ammonia source, an oxygen source and a m-xylene feedstock with the catalyst for reaction.

[0014] Through the above technical solution, the present invention has the following beneficial effects:

[0015] 1. Through extensive research, the inventors discovered that the catalyst includes a support and an active component. The active component elements include vanadium, bismuth, and boron. The active component contains BiVO4 crystals. When the ratio of the intensity of the main diffraction characteristic peaks attributable to V2O5 and / or Bi2O3 to the intensity of the main diffraction characteristic peaks attributable to BiVO4 in the XRD pattern of the catalyst is 0 to 0.15:1, it can significantly improve the activity and selectivity of the reaction for the co-production of m-alkylbenzonitrile and m-phenylalkylnitrile by gas-phase ammonia oxidation of m-alkylbenzene, thus realizing the co-production of m-alkylbenzonitrile and m-phenylalkylnitrile.

[0016] 2. The ammonia oxidation catalyst prepared by the method of the present invention has high particle strength. When applied to a fluidized bed reactor, it avoids problems such as difficulty in heat removal in a fixed bed reaction system. It has low equipment investment and obvious operating cost advantages.

[0017] 3. When the catalyst of this invention is used for the gas-phase ammonia oxidation of m-xylene, compared with the chemical synthesis of m-methylbenzonitrile, this invention achieves one-step synthesis through the gas-phase ammonia oxidation of m-xylene, which greatly shortens the reaction steps, significantly improves production efficiency, and has a significant cost advantage. Attached Figure Description

[0018] Figure 1 This is the XRD pattern of the catalyst prepared in Example 1;

[0019] Figure 2 The XRD pattern of the catalyst prepared in Comparative Example 1 is shown.

[0020] Figure 3 This is the XRD pattern of the catalyst prepared in Comparative Example 2. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of 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.

[0022] The first aspect of the present invention provides an ammonia oxidation catalyst, the catalyst comprising a support and an active component, the active component comprising vanadium, bismuth and boron, the active component comprising BiVO4 crystals, and the ratio of the intensity of the main diffraction characteristic peaks attributable to V2O5 and / or Bi2O3 to the intensity of the main diffraction characteristic peaks attributable to BiVO4 in the XRD pattern of the catalyst being 0 to 0.15:1, preferably 0 to 0.1:1.

[0023] The catalyst of this invention includes a support and an active component. The active component elements include vanadium, bismuth, and boron. The active component contains BiVO4 crystals. When the ratio of the intensity of the main diffraction characteristic peaks attributable to V2O5 and / or Bi2O3 to the intensity of the main diffraction characteristic peaks attributable to BiVO4 in the XRD pattern of the catalyst is 0 to 0.15:1, it can significantly improve the activity and selectivity of the reaction for the co-production of m-alkylbenzonitrile and m-phenylalkylnitrile by gas-phase ammonia oxidation of m-alkylbenzene, thus realizing the co-production of m-alkylbenzonitrile and m-phenylalkylnitrile.

[0024] In this invention, as long as the objective of the invention can be achieved, there are no particular limitations on the content of the support and the content of the active component in the catalyst. According to a preferred embodiment of the invention, based on the total mass of the catalyst, the support content is 20wt% to 75wt%, and the active component content is 25wt% to 80wt%. Preferably, the mass ratio of the active component to the support in the catalyst is (0.6 to 1.6):1. By adopting the aforementioned preferred embodiment, the reaction activity and product selectivity of the catalyst can be further improved.

[0025] In this invention, in order to further improve the reaction activity and product selectivity of the catalyst, the mass content of BiVO4 crystals in the catalyst is 25% to 75 wt%, preferably 33% to 60 wt%, for example, it can be 25 wt%, 30% wt%, 35 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, or 75 wt%.

[0026] Furthermore, in this invention, BiVO4 crystals account for 75% to 98 wt% of the active component, preferably 80% to 98 wt%, for example, 75 wt%, 80 wt%, 85 wt%, 90 wt%, or 98 wt%. By adopting the aforementioned preferred embodiment, the reaction activity of the catalyst and the product selectivity can be further improved.

[0027] In this invention, the structure of the active component is not particularly limited as long as the objective of the invention can be achieved. According to a preferred embodiment of the invention, the active component is composed of V. 1.0 Bi a B b O e The structure is defined as follows: a ranges from 0.6 to 2.5, b ranges from 0.4 to 1.1, and e is the number of oxygen atoms required to satisfy the oxidation states of each element in the active component.

[0028] According to a preferred embodiment of the present invention, the boron exists in the form of an amorphous oxide.

[0029] According to a preferred embodiment of the present invention, the composition of the active component is as shown in formula (1):

[0030] V 1.0 Bi a B b X c Y d O e Equation (1)

[0031] Where a ranges from 0.6 to 2.5, b ranges from 0.4 to 1.1, c ranges from 0.01 to 0.5, d ranges from 0.01 to 0.2, f ranges from 0 to 0.5, and e is the number of oxygen atoms required to satisfy the oxidation states of each element in the active component.

[0032] X is selected from at least one of the elements Te, Mn, Co, Ti, P, Mo, and W;

[0033] Y is selected from at least one element from Group IA and Group IIA, preferably at least one element from K, Ba, Rb, and Cs;

[0034] X exists in the form of an amorphous oxide, and Y exists in the form of an amorphous oxide.

[0035] By employing the aforementioned preferred embodiments, the reaction activity of the catalyst and the product selectivity can be further improved. This invention uses a = 1.0, b = 0.5, c = 0.27, and d = 0.03 to illustrate the advantages of a preferred embodiment of the invention.

[0036] According to a preferred embodiment of the present invention, the XRD pattern of the catalyst shows obvious BiVO4 diffraction peaks at 2θ positions of 18.7°, 19.0°, 28.9°, 30.5°, 34.5°, 35.2°, 40.2°, 42.5°, 45.8°, 46.5°, 50.3°, 53.0°, 58.5°, and 59.2°; optionally, obvious V2O5 diffraction peaks are present at 2θ positions of 15.39°, 20.31°, 26.2°, 31.0°, 32.4°, 34.3°, 51.3°, and 61.1°; optionally, obvious Bi2O3 diffraction peaks are present at 2θ positions of 27.4°, 30.1°, 32.6°, 51.9°, 55.0°, and 61.2°.

[0037] In this invention, as long as the objective of the invention can be achieved, there are no special requirements for the specific surface area of ​​the catalyst. According to a preferred embodiment of the invention, the BET specific surface area of ​​the catalyst is between 12 and 35 m². 2 ·g -1 Preferably 18–23m 2 ·g -1 By adopting the aforementioned preferred methods, the reaction activity of the catalyst and the product selectivity can be further improved.

[0038] According to a preferred embodiment of the present invention, the median particle size of the catalyst is 45 μm to 55 μm, the particle size range is 1 μm to 120 μm, and the attenuation rate is less than 1.2 wt%.

[0039] In this invention, the support can be a conventional choice in the art. According to a preferred embodiment of the invention, the support is selected from at least one of SiO2, Al2O3, TiO2, ZrO2, MgO, and molecular sieves, preferably SiO2. By adopting the aforementioned preferred option, the reaction activity of the catalyst and the product selectivity can be further improved.

[0040] The catalyst of this invention can be used in conventional fluidized bed reactors. As long as the fluidization quality is ensured, abnormal fluidization phenomena such as channeling, bubbles, and surging are avoided, and the degree of backmixing of the gas flow is reduced, a high product yield can be guaranteed.

[0041] In this invention, catalysts possessing the aforementioned characteristics can achieve the objectives of this invention. The preparation of such catalysts can be carried out using conventional methods in the art. Specifically, this invention provides a method for preparing the aforementioned catalyst, the method comprising:

[0042] (1) Mix the vanadium source, reducing agent and first solvent to prepare solution A;

[0043] (2) First, add boron source and organic acid additive to the second solvent, then add bismuth source to the second mixture to obtain solution B;

[0044] (3) After mixing solution A and solution B, add optional source X and optional source Y to dissolve the prepared solution, and then add it to the carrier source to obtain mixed slurry L;

[0045] (4) The mixed slurry L is heated and concentrated to prepare a slurry;

[0046] (5) The slurry obtained in step (4) is spray-dried and shaped, and then calcined to obtain the catalyst.

[0047] Steps (1) and (2) are used only to distinguish between two different steps and have no order of precedence.

[0048] The catalyst prepared by the method of this invention has the aforementioned characteristics and high particle strength. When applied to a fluidized bed reactor, it avoids the problems of heat removal difficulties in a fixed bed reaction system. It also has low equipment investment and obvious operating cost advantages.

[0049] In this invention, the organic acid promoter can be a conventional choice in the art. According to a preferred embodiment of the invention, the organic acid promoter is selected from at least one of lactic acid, tartaric acid, citric acid, and methanesulfonic acid, preferably citric acid. By adopting the aforementioned preferred option, the activity and product selectivity of the prepared catalyst can be further improved.

[0050] In this invention, the reducing agent can be a conventional choice in the art. According to a preferred embodiment of the invention, the reducing agent is selected from at least one of oxalic acid monohydrate, formic acid, citric acid, and hydroxylamine hydrochloride, preferably oxalic acid monohydrate.

[0051] In this invention, the vanadium source can be a conventional choice in the art. According to a preferred embodiment of the invention, the vanadium source is selected from at least one of vanadium pentoxide, ammonium metavanadate, vanadium sulfate, vanadium oxalate, and vanadium tartrate.

[0052] In this invention, the bismuth source can be a conventional choice in the art. According to a preferred embodiment of the invention, the bismuth source is selected from at least one of bismuth nitrate, bismuth nitrate hydrate, bismuth chloride, and basic bismuth carbonate.

[0053] In this invention, the boron source can be a conventional choice in the art. According to a preferred embodiment of the invention, the boron source is selected from at least one of boric acid, borax, and boromagnesia.

[0054] In this invention, the X source can be a conventional choice in the art. According to a preferred embodiment of the invention, the X source is selected from at least one of the acids, ammonium salts, oxides and organic compounds corresponding to the X element, preferably ammonium molybdate.

[0055] In this invention, the Y source can be a conventional choice in the art. According to a preferred embodiment of the invention, the Y source is selected from at least one of the acids, ammonium salts, oxides, nitrates, oxalates and carbonates corresponding to the Y element, preferably potassium nitrate.

[0056] In this invention, the carrier source can be a conventional choice in the art. According to a preferred embodiment of the invention, the carrier source is selected from at least one of silica sol, Al2O3, TiO2, ZrO2, MgO and molecular sieve, and preferably the concentration of the silica sol is 30-50 wt%.

[0057] In this invention, the first solvent can be a conventional choice in the art, as long as it can completely dissolve the vanadium source and the reducing agent. According to a preferred embodiment of this invention, the first solvent is selected from at least one of water, benzyl alcohol, isobutanol, and methanol.

[0058] In this invention, the second solvent can be a conventional choice in the art, as long as it can completely dissolve the boron source and the organic acid additive. According to a preferred embodiment of this invention, the second solvent is selected from at least one of water, benzyl alcohol, isobutanol, and methanol.

[0059] In this invention, as long as the objective of this invention can be achieved, there is no particular limitation on the molar ratio of the amount of reducing agent added in step (1) to the amount of vanadium source added, calculated as vanadium. According to a preferred embodiment of this invention, the molar ratio of the amount of reducing agent added in step (1) to the amount of vanadium source added, calculated as vanadium, is 1 to 1.25:1. By adopting the aforementioned preferred embodiment, the activity and product selectivity of the prepared catalyst can be further improved.

[0060] In this invention, as long as the objective of this invention can be achieved, there is no particular limitation on the molar ratio of the amount of organic acid auxiliary agent added in step (2) to the amount of bismuth source added (calculated as bismuth). According to a preferred embodiment of this invention, the molar ratio of the amount of auxiliary agent added in step (2) to the amount of bismuth source added (calculated as bismuth) is 0.3 to 1:1. By adopting the aforementioned preferred embodiment, the activity and product selectivity of the prepared catalyst can be further improved.

[0061] In this invention, as long as the objective of this invention can be achieved, there is no particular limitation on the solid content of the slurry in step (4). According to a preferred embodiment of this invention, the solid content of the slurry in step (4) is 30wt% to 65wt%. By adopting the aforementioned preferred embodiment, the activity and product selectivity of the prepared catalyst can be further improved.

[0062] In this invention, the conditions for spray drying molding can be conventional choices in the art. According to a preferred embodiment of this invention, the conditions for spray drying molding include: gas inlet temperature 350-400℃, outlet temperature 150-200℃, and centrifugal nozzle speed 4000-5000 rpm.

[0063] In this invention, the calcination conditions can be conventionally selected in the art. According to a preferred embodiment of this invention, the calcination conditions include: a calcination temperature of 500-700°C and a calcination time of 6-15 hours.

[0064] In this invention, the conditions for the first mixing can be conventional choices in the art. According to a preferred embodiment of the invention, the conditions for the first mixing include a temperature of 80-90°C.

[0065] In this invention, the conditions for the second mixing can be conventional choices in the art. According to a preferred embodiment of the invention, the conditions for the second mixing include a temperature of 80-90°C.

[0066] This invention provides a gas-phase ammonia oxidation of m-xylene to co-produce m-methylbenzonitrile and isophthalonitrile.

[0067] The method, using the catalyst, includes reacting an ammonia source, an oxygen source, and a m-xylene feedstock with the catalyst.

[0068] The reaction formula for the contact reaction is:

[0069]

[0070] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: a reaction temperature of 320-450°C, and / or a reaction pressure of 101 kPa-160 kPa, and / or a reaction time sufficient for complete reaction, preferably 4-10 h.

[0071] According to a preferred embodiment of the present invention, the conditions for the contact reaction further include: the feed molar ratio of ammonia source (NH3), oxygen source (O2), and m-xylene feedstock (m-xylene) is NH3:O2:m-xylene = 1-10:2-9:1, preferably 4-10:3-9:1.

[0072] According to a preferred embodiment of the present invention, the contact reaction conditions further include: a catalyst loading of 0.052-0.082 h. -1 .

[0073] According to a preferred embodiment of the present invention, the contact reaction conditions further include: the ammonia source is ammonia gas. In the reaction process of the present invention, the ratio of the molar number of NH3 feed to the molar number of m-xylene is at least 1.0 times the theoretical stoichiometric value for the reaction, preferably in the range of 4 to 10 times.

[0074] According to a preferred embodiment of the present invention, the conditions for the contact reaction further include: the oxygen source is air; when air is used as the oxygen source, the volume concentration of m-xylene feedstock in the feed mixture is 1% to 15%, preferably 2% to 8%, wherein the ratio of the number of moles of oxygen feedstock to the number of moles of m-xylene is more than twice the stoichiometric value for the reaction, preferably in the range of 3 to 9 times. Generally, a low oxygen ratio will lead to a decrease in reaction conversion and an increase in the selectivity of m-methylbenzonitrile, while a high oxygen ratio will lead to deep oxidation.

[0075] The present invention will be described in detail below through embodiments. The following embodiments include:

[0076] All raw materials are commercially available:

[0077] In this invention, the crystal structure of the molecular sieve is determined by X-ray diffraction (XRD) using a Bruker D8 X-ray powder diffractometer (XRD) from Germany, with a Cu-Kα ray source and a Kα1 wavelength λ = 1.5405980 angstroms. Nickel filter, operating voltage 40kV, current 40mA, scanning range 2θ=5~80°;

[0078] In this invention, the abrasion rate is tested using a method conforming to ASTM D5757-00 (using air jet abrasion to determine the relative abrasion characteristics of powdered catalysts). The abrasion rate of the finished catalyst is measured as the abrasion rate per hour, expressed in wt%.

[0079] In the embodiments and comparative examples of this invention, the catalyst evaluation adopts... The process was carried out in a reactor with a length of 1800 mm and a catalyst loading of 550 g.

[0080] In this invention, the conversion rate of m-xylene, the selectivity of m-methylbenzonitrile, the selectivity of m-phthalonitrile, the yield of m-methylbenzonitrile, and the yield of m-phthalonitrile are defined as follows:

[0081]

[0082]

[0083]

[0084]

[0085]

[0086] Example 1

[0087] Preparation of catalyst A:

[0088] 140g of V2O5 was added to 600ml of water containing 141g of oxalic acid monohydrate, which was preheated to 85℃ and stirred thoroughly to obtain blue solution A.

[0089] Add 48g boric acid and 238.5g citric acid to 800g water, dissolve 747g bismuth nitrate in the solution, and heat to approximately 90℃ to obtain solution B. Mix A and B, then add a solution prepared with 6g ammonium molybdate and 100g water, a solution prepared with 4.7g potassium nitrate and 8g water, and 0.38mol phosphoric acid. Slowly add the above solution to 1250g silica sol with a SiO2 content of 40wt% under stirring to obtain a dark yellow mixture. Heat and concentrate under stirring to obtain a viscous slurry with a solid content of 30wt%.

[0090] The above slurry was spray-dried and shaped. The inlet temperature of the spray dryer was 380℃, the outlet temperature was 175℃, and the centrifugal nozzle speed was 4500 rpm. The fine catalyst particles obtained by spraying were calcined at 600℃ for 10 hours to obtain catalyst A, whose composition is V. 1.0 Bi 1.0 Mo 0.02 P 0.25 B 0.5 K 0.03 The catalyst A contains SiO2, where the active component to support mass ratio is 1.12:1 (active component content is 53 wt%), and the median particle size of catalyst A is 52 μm. BiVO4 accounts for 47 wt% of catalyst A. XRD characterization of catalyst A is shown in [reference needed]. Figure 1Catalyst A exhibits distinct BiVO4 diffraction peaks at 2θ positions of 18.7°, 19.0°, 28.9°, 30.5°, 34.5°, 35.2°, 40.2°, 42.5°, 45.8°, 46.5°, 50.3°, 53.0°, 58.5°, and 59.2°; distinct V2O5 diffraction peaks at 2θ positions of 15.39°, 20.31°, 26.2°, 31.0°, 32.4°, 34.3°, 51.3°, and 61.1°; and distinct Bi2O3 diffraction peaks at 2θ positions of 27.4°, 30.1°, 32.6°, 51.9°, 55.0°, and 61.2°. BiVO4 crystals constitute 88.7 wt% of the active component, and the ratio of the intensity of the diffraction characteristic peaks is 0.032:1.

[0091] Catalyst A performance evaluation:

[0092] The feed molar ratio was m-xylene: NH3: air (as O2) = 1:9:6, and the catalyst loading was 0.060 h⁻¹. -1 ;

[0093] The reaction temperature was 405℃, the reaction pressure was 101kPa, and the reaction time was 8h.

[0094] Reaction results:

[0095] m-Xylene conversion rate: 92.3%;

[0096] m-Toluenebenzonitrile selectivity 42.7%;

[0097] The selectivity of isophthalonitrile was 39.9%.

[0098] m-Toluenebenzonitrile yield 39.4%;

[0099] The yield of isophthalonitrile was 36.8%.

[0100] Catalyst attrition rate: 1.1%.

[0101] Example 2

[0102] Preparation of catalyst B:

[0103] 125g of V2O5 was added to 535ml of water containing 126g of oxalic acid monohydrate, which was preheated to 85℃ and stirred thoroughly to obtain blue solution A.

[0104] Add 43g boric acid and 142g tartaric acid to 714g water, dissolve 667g bismuth nitrate in the solution, and heat to approximately 90℃ to obtain solution B. Mix A and B, then add a solution prepared with 5.4g ammonium molybdate and 85g water, a solution prepared with 4.2g potassium nitrate and 6g water, and 0.34mol phosphoric acid. Slowly add the above solution to 1250g silica sol with a SiO2 content of 40wt% under stirring to obtain a dark yellow mixture. Heat and concentrate under stirring to obtain a viscous slurry with a solid content of 30wt%.

[0105] The above slurry was spray-dried and shaped. The inlet temperature of the spray dryer was 380℃, the outlet temperature was 175℃, and the centrifugal nozzle speed was 4500 rpm. The fine catalyst particles obtained by spraying were calcined at 600℃ for 10 hours to obtain catalyst B, whose composition is V. 1.0 Bi 1.0 Mo 0.02 P 0.25 B 0.5 K 0.03 The catalyst B contains SiO2, in which the mass ratio of active component to support is 1:1 (active component content is 50wt%), and the median particle size of catalyst B is 51μm. BiVO4 accounts for 44.6wt% of the weight of catalyst B, and BiVO4 crystals account for 89.2wt% of the mass of active component, with a diffraction characteristic peak intensity ratio of 0.03:1.

[0106] Catalyst B performance evaluation:

[0107] The feed molar ratio was m-xylene: NH3: air (as O2) = 1:9:6, and the catalyst loading was 0.060 h⁻¹. -1 .

[0108] The reaction temperature was 405℃, the reaction pressure was 101kPa, and the reaction time was 8h.

[0109] Reaction results:

[0110] m-Xylene conversion rate: 90.2%;

[0111] m-Toluenebenzonitrile selectivity 43.1%;

[0112] The selectivity of isophthalonitrile was 40.2%.

[0113] m-Toluenebenzonitrile yield 38.9%;

[0114] The yield of isophthalonitrile was 36.2%.

[0115] Catalyst attrition rate: 1.06%.

[0116] Example 3

[0117] Preparation of catalyst C:

[0118] 150g of V2O5 was added to 650ml of water containing 151g of oxalic acid monohydrate, which was preheated to 85℃ and stirred thoroughly to obtain blue solution A.

[0119] Add 52g of boric acid and 127.8g of tartaric acid to 857g of water, dissolve 800g of bismuth nitrate in the solution, and heat to approximately 90℃ to obtain solution B. Mix A and B, then add a solution prepared with 6.5g of ammonium molybdate and 110g of water, a solution prepared with 5g of potassium nitrate and 7g of water, and 0.41mol of phosphoric acid. Slowly add the above solution to 1250g of silica sol with a SiO2 content of 40wt% under stirring to obtain a dark yellow mixture. Heat and concentrate under stirring to obtain a viscous slurry with a solid content of 30wt%.

[0120] The above slurry was spray-dried and shaped. The inlet temperature of the spray dryer was 380℃, the outlet temperature was 175℃, and the centrifugal nozzle speed was 4500 rpm. The fine catalyst particles obtained by spraying were calcined at 600℃ for 10 hours to obtain catalyst A, whose composition is V. 1.0 Bi 1.0 Mo 0.02 P 0.25 B 0.5 K 0.03 The catalyst C contains SiO2, in which the mass ratio of active component to support is 1.2:1 (active component content is 55wt%), and the median particle size of catalyst C is 50μm. BiVO4 accounts for 48.9wt% of the weight of catalyst C, and BiVO4 crystals account for 88.9wt% of the mass of active component, with a diffraction characteristic peak intensity ratio of 0.031:1.

[0121] The performance evaluation of catalyst C is the same as in Example 1.

[0122] Reaction results:

[0123] m-Xylene conversion rate: 94.8%;

[0124] m-Toluenebenzonitrile selectivity 41.2%;

[0125] The selectivity of isophthalonitrile was 40.6%.

[0126] m-Toluenebenzonitrile yield 39.1%;

[0127] The yield of isophthalonitrile was 37.1%.

[0128] Catalyst attrition rate: 1.07%.

[0129] Example 4

[0130] Preparation of catalyst D:

[0131] Similar to Example 1, except that the mass ratio of active component to support in catalyst D is 1.6:1 (active component content is 61.5 wt%), and the median particle size of catalyst D is 50 μm. BiVO4 accounts for 52.9 wt% of the weight of catalyst D. BiVO4 crystals account for 86 wt% of the active component, and the ratio of diffraction characteristic peak intensities is 0.08:1.

[0132] The performance evaluation of catalyst D is the same as in Example 1;

[0133] Reaction results:

[0134] m-Xylene conversion rate: 93.1%;

[0135] m-Toluenebenzonitrile selectivity 40.3%;

[0136] The selectivity of isophthalonitrile was 38.2%.

[0137] m-Toluenebenzonitrile yield 37.5%;

[0138] The yield of isophthalonitrile was 35.6%.

[0139] Catalyst attrition rate: 1.1%.

[0140] Example 5

[0141] Preparation of catalyst F:

[0142] Similar to Example 1, except that the mass ratio of active component to support in catalyst F is 0.6:1 (active component content is 37.5 wt%), and the median particle size of catalyst F is 53 μm. BiVO4 accounts for 32.9 wt% of catalyst F, BiVO4 crystals account for 87.7 wt% of the active component, and the ratio of diffraction characteristic peak intensities is 0.05:1.

[0143] The performance evaluation of catalyst F is the same as in Example 1;

[0144] Reaction results:

[0145] m-Xylene conversion rate: 90.2%;

[0146] m-Toluenebenzonitrile selectivity 41.1%;

[0147] The selectivity of isophthalonitrile was 38.9%.

[0148] m-Toluenebenzonitrile yield 37.3%;

[0149] The yield of isophthalonitrile was 35.1%.

[0150] Catalyst attrition rate: 1.08%.

[0151] Example 6

[0152] Preparation of catalyst G:

[0153] Similar to Example 1, except that all raw materials were dissolved and directly mixed, then added to the silica sol support, heated and concentrated, and then sprayed and calcined to obtain catalyst G. The median particle size of catalyst G is 51 μm. BiVO4 crystals account for 38.6 wt% of the weight of catalyst G. BiVO4 crystals account for 73 wt% of the active component, and the ratio of diffraction characteristic peak intensities is 0.12:1.

[0154] The performance evaluation of catalyst G is the same as in Example 1;

[0155] Reaction results:

[0156] m-Xylene conversion rate: 95.2%;

[0157] m-Toluenebenzonitrile selectivity 36.4%;

[0158] The selectivity of isophthalonitrile was 34.2%.

[0159] m-Toluenebenzonitrile yield 34.7%;

[0160] The yield of isophthalonitrile was 32.6%.

[0161] Catalyst attrition rate: 2.09%.

[0162] Example 7

[0163] Preparation of catalyst H:

[0164] Similar to Example 1, except that methanesulfonic acid was used as the organic acid promoter, and the median particle size of catalyst H was 51 μm. BiVO4 accounted for 40.4 wt% of the weight of catalyst H. BiVO4 crystals accounted for 76 wt% of the active component, and the ratio of diffraction characteristic peak intensities was 0.11:1.

[0165] The performance evaluation of catalyst H is the same as in Example 1;

[0166] Reaction results:

[0167] m-Xylene conversion rate: 96.1%;

[0168] m-Toluenebenzonitrile selectivity 36.5%;

[0169] The selectivity of isophthalonitrile was 34.1%.

[0170] m-Toluenebenzonitrile yield 35.1%;

[0171] The yield of isophthalonitrile was 32.8%.

[0172] The catalyst attrition rate was 1.12%.

[0173] Example 8

[0174] Preparation of Catalyst I:

[0175] Same as Example 1, except that the mass ratio of active component to support in catalyst I is 3.5:1 (active component content is 78wt%), and the median particle size of catalyst I is 55μm. BiVO4 accounts for 61.6wt% of the weight of catalyst I. BiVO4 crystals account for 79wt% of the active component, and the ratio of diffraction characteristic peak intensities is 0.08:1.

[0176] The performance evaluation of catalyst I is the same as in Example 1;

[0177] Reaction results:

[0178] m-Xylene conversion rate: 95.2%;

[0179] m-Toluenebenzonitrile selectivity 37.6%;

[0180] The selectivity of isophthalonitrile was 36.2%.

[0181] m-Toluenebenzonitrile yield 35.8%;

[0182] The yield of isophthalonitrile was 34.5%.

[0183] Catalyst attrition rate: 1.1%.

[0184] Example 9

[0185] Preparation of catalyst J:

[0186] Same as Example 1, except that the evaluation conditions for the catalyst are changed.

[0187] Catalyst J performance evaluation:

[0188] The feed molar ratio was m-xylene:NH3:O2 = 1:12:10, and the catalyst loading was 0.085 h⁻¹. -1 ;

[0189] Reaction temperature 455℃;

[0190] Reaction results:

[0191] m-Xylene conversion rate: 98.6%;

[0192] m-Toluenebenzonitrile selectivity 35.6%;

[0193] The selectivity of isophthalonitrile was 34.4%.

[0194] m-Toluenebenzonitrile yield 35.1%;

[0195] The yield of isophthalonitrile was 33.9%.

[0196] The catalyst attrition rate is 1.15%.

[0197] Comparative Example 1

[0198] Preparation of DA catalyst:

[0199] 140g of V2O5 was added to 600ml of water containing 141g of oxalic acid monohydrate, which was preheated to 80-90℃ and stirred thoroughly to obtain blue solution A.

[0200] A solution prepared by mixing 48g of boric acid with 250g of boiling water, a solution prepared by mixing 6g of ammonium molybdate with 100g of water, a solution prepared by mixing 4.7g of potassium nitrate with 8g of water, and 0.38 mol of phosphoric acid were slowly added to 1250g of silica sol with a SiO2 content of 40wt% under stirring. The mixture was then heated and concentrated under stirring to obtain a viscous slurry with a solid content of 30wt%.

[0201] The above slurry was spray-dried and shaped. The inlet temperature of the spray dryer was 380℃, the outlet temperature was 175℃, and the centrifugal nozzle speed was 4500 rpm. The fine catalyst particles obtained by spraying were calcined at 600℃ for 10 hours to obtain catalyst DA, whose composition is V. 1.0 Mo 0.02 P 0.25 B 0.5 K 0.03 XRD characterization of the / SiO2 catalyst DA is shown in [reference needed]. Figure 2 Catalyst DB exhibits a V₂O₅ crystalline phase. The active component to support mass ratio in catalyst DA is 0.4:1, and the median particle size of catalyst DA is 50 μm. V₂O₅ accounts for 20 wt% of catalyst DA.

[0202] The performance evaluation of the catalyst DA is the same as in Example 1;

[0203] Reaction results:

[0204] m-Xylene conversion rate: 98.5%;

[0205] m-Toluenebenzonitrile selectivity 10.1%;

[0206] The selectivity of isophthalonitrile was 26.2%.

[0207] m-Toluenebenzonitrile yield 9.9%;

[0208] The yield of isophthalonitrile was 25.8%.

[0209] Catalyst attrition rate: 1.05%.

[0210] Comparative Example 2

[0211] Preparation of catalyst DB:

[0212] 140g of V2O5 was added to 600ml of water containing 141g of oxalic acid monohydrate and preheated to 80-90℃, and stirred thoroughly to obtain blue solution A;

[0213] Add 48g of boric acid to 800g of water, dissolve 747g of bismuth nitrate in the solution, and heat to approximately 90℃ to obtain solution B. Mix solution A and solution B, then add a solution prepared with 6g of ammonium molybdate and 100g of water, a solution prepared with 4.7g of potassium nitrate and 8g of water, and 0.38mol of phosphoric acid. Slowly add the above solution to 1250g of silica sol with a SiO2 content of 40wt% under stirring to obtain a dark yellow mixture. Concentrate the mixture under stirring to obtain a viscous slurry with a solid content of 30wt%.

[0214] The above slurry was spray-dried and shaped. The inlet temperature of the spray dryer was 380℃, the outlet temperature was 175℃, and the centrifugal nozzle speed was 4500 rpm. The fine catalyst particles obtained by spraying were calcined at 600℃ for 10 hours to obtain catalyst DB, whose composition is V. 1.0 Bi 1.0 Mo 0.02 P 0.25 B 0.5 K 0.03 The catalyst DB contains SiO2, where the active component to support mass ratio is 1.12:1 (active component content is 53 wt%), and the median particle size of catalyst DB is 52 μm. BiVO4 accounts for 37.6 wt% of catalyst DB. XRD characterization of catalyst DB is shown below. Figure 3 The catalyst DB exhibits BiVO4 and V2O5 crystal phases, with BiVO4 crystals accounting for 70.96 wt% of the active component and the ratio of diffraction characteristic peak intensities being 0.28:1.

[0215] The performance evaluation of catalyst DB is the same as in Example 1.

[0216] Reaction results:

[0217] m-Xylene conversion rate: 97.5%;

[0218] m-Toluenebenzonitrile selectivity 30.4%;

[0219] The selectivity of isophthalonitrile was 31.0%.

[0220] m-Toluenebenzonitrile yield 29.6%;

[0221] The yield of isophthalonitrile was 30.4%.

[0222] Catalyst attrition rate: 1.1%.

[0223] Comparative Example 3

[0224] Preparation of DC catalyst:

[0225] 140g of V2O5 was added to 600ml of water containing 141g of oxalic acid monohydrate, which was preheated to 80-90℃ and stirred thoroughly to obtain blue solution A.

[0226] Add 238.5g of citric acid to 800g of water, dissolve 747g of bismuth nitrate in the solution, and heat to approximately 90℃ to obtain solution B. Mix A and B, then add a solution prepared with 12g of ammonium molybdate and 200g of water, a solution prepared with 4.7g of potassium nitrate and 8g of water, and 0.38mol of phosphoric acid. Slowly add the above solution to 1250g of silica sol with a SiO2 content of 40wt% under stirring to obtain a dark yellow mixture. Heat and concentrate under stirring to obtain a viscous slurry with a solid content of 30wt%.

[0227] The above slurry was spray-dried and shaped. The inlet temperature of the spray dryer was 380℃, the outlet temperature was 175℃, and the centrifugal nozzle speed was 4500 rpm. The fine catalyst particles obtained by spraying were calcined at 600℃ for 10 hours to obtain catalyst DC, whose composition is V. 1.0 Bi 1.0 Mo 0.04 P 0.25 K 0.03 The catalyst DC contains SiO2, in which the mass ratio of active component to support is 1.08:1 (active component content is 51.9 wt%), and the median particle size of catalyst DC is 50 μm. BiVO4 accounts for 31.5 wt% of catalyst DC. BiVO4 crystals account for 60.7 wt% of the active component, and the ratio of diffraction characteristic peak intensities is 0.2:1.

[0228] The performance evaluation of the catalyst DC was the same as in Example 1;

[0229] Reaction results:

[0230] m-Xylene conversion rate: 94.3%;

[0231] m-Toluenebenzonitrile selectivity 28.6%;

[0232] The selectivity of isophthalonitrile was 27.4%.

[0233] m-Toluenebenzonitrile yield 30.0%;

[0234] The yield of isophthalonitrile was 25.8%.

[0235] The catalyst attrition rate was 1.11%.

[0236] As can be seen from the results in Table 1, the technical solution of the present invention can achieve good co-production of m-methylbenzonitrile and isophthalonitrile. The selectivity of each is above 34%, and the sum of the selectivities is above 70%, and the sum of the molar yields can reach above 60%.

[0237] 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 technical features in any other suitable manner. 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.

Claims

1. A method for the gas-phase ammonia oxidation of m-xylene to co-produce m-methylbenzonitrile and isophthalonitrile, characterized in that, Using an ammonia oxidation catalyst, the method includes: contacting an ammonia source, an oxygen source, and a m-xylene feedstock with the catalyst for reaction; wherein... The catalyst includes a support and an active component. The active component elements include vanadium, bismuth, and boron. The active component contains BiVO4 crystals. The ratio of the intensity of the main diffraction characteristic peaks attributable to V2O5 and / or Bi2O3 to the intensity of the main diffraction characteristic peaks attributable to BiVO4 in the XRD spectrum of the catalyst is 0 to 0.15:1, and the ratio is not 0. In the catalyst, BiVO4 crystals account for 75wt%~98wt% of the active component by mass; The composition of the active component is shown in formula (1): V 1.0 Bi a B b X c Y d O e Formula (1) Where a ranges from 0.6 to 2.5, b ranges from 0.4 to 1.1, c ranges from 0.01 to 0.5, d ranges from 0.01 to 0.2, and e is the number of oxygen atoms required to satisfy the oxidation states of each element in the active component. X is selected from at least one of the elements Te, Mn, Co, Ti, P, Mo, and W; Y is selected from at least one element from Group IA and Group IIA; X exists in the form of an amorphous oxide, and Y exists in the form of an amorphous oxide.

2. The method according to claim 1, wherein, The ratio of the intensity of the main diffraction characteristic peaks attributed to V₂O₅ and / or Bi₂O₃ to the intensity of the main diffraction characteristic peaks attributed to BiVO₄ in the XRD pattern of the catalyst is 0 to 0.1:1, and the ratio is not 0; and / or Based on the total mass of the catalyst, the support content is 20wt%~75wt%, the active component content is 25wt%~80wt%; and / or The catalyst contains BiVO4 crystals at a mass content of 25wt%~75wt%; and / or In the catalyst, BiVO4 crystals account for 80wt%~98wt% of the active component; and / or Boron exists in the form of amorphous oxides.

3. The method according to claim 2, wherein, In the catalyst, the mass ratio of the active component to the support is (0.6~1.6):1; and / or The catalyst contains BiVO4 crystals at a mass content of 33wt% to 60wt%.

4. The method according to claim 1, wherein, Y is at least one of the elements K, Ba, Rb, and Cs.

5. The method according to any one of claims 1-3, wherein, The XRD pattern of the catalyst is shown in 2 θ Obvious BiVO4 diffraction peaks are observed at positions of 18.7º, 19.0º, 28.9º, 30.5º, 34.5º, 35.2º, 40.2º, 42.5º, 45.8º, 46.5º, 50.3º, 53.0º, 58.5º, and 59.2º; at 2 θ Obvious V₂O₅ diffraction peaks are observed at positions of 15.39º, 20.31º, 26.2º, 31.0º, 32.4º, 34.3º, 51.3º, and 61.1º; and / or The catalyst has a BET specific surface area of ​​12-35 m². 2 ·g -1 ; and / or The catalyst has a median particle size of 45 μm to 55 μm, a particle size range of 1 μm to 120 μm, and an attenuation rate of less than 1.2 wt%.

6. The method according to claim 5, wherein, The catalyst has a BET specific surface area of ​​18-23 m². 2 ·g -1 .

7. The method according to any one of claims 1-3, wherein, The XRD pattern of the catalyst is shown in 2 θ Obvious BiVO4 diffraction peaks are observed at positions of 18.7º, 19.0º, 28.9º, 30.5º, 34.5º, 35.2º, 40.2º, 42.5º, 45.8º, 46.5º, 50.3º, 53.0º, 58.5º, and 59.2º; at 2 θ Obvious Bi₂O₃ diffraction peaks are observed at positions of 27.4º, 30.1º, 32.6º, 51.9º, 55.0º, and 61.2º; and / or The catalyst has a BET specific surface area of ​​12-35 m². 2 ·g -1 ; and / or The catalyst has a median particle size of 45 μm to 55 μm, a particle size range of 1 μm to 120 μm, and an attenuation rate of less than 1.2 wt%.

8. The method according to claim 7, wherein, The catalyst has a BET specific surface area of ​​18-23 m². 2 ·g -1 .

9. The method according to any one of claims 1-3, wherein, The XRD pattern of the catalyst is shown in 2 θ Obvious BiVO4 diffraction peaks are observed at positions of 18.7º, 19.0º, 28.9º, 30.5º, 34.5º, 35.2º, 40.2º, 42.5º, 45.8º, 46.5º, 50.3º, 53.0º, 58.5º, and 59.2º; at 2 θ Obvious V₂O₅ diffraction peaks are observed at positions of 15.39º, 20.31º, 26.2º, 31.0º, 32.4º, 34.3º, 51.3º, and 61.1º; at 2 θ Obvious Bi₂O₃ diffraction peaks are observed at positions of 27.4º, 30.1º, 32.6º, 51.9º, 55.0º, and 61.2º; and / or The catalyst has a BET specific surface area of ​​12-35 m². 2 ·g -1 ; and / or The catalyst has a median particle size of 45 μm to 55 μm, a particle size range of 1 μm to 120 μm, and an attenuation rate of less than 1.2 wt%.

10. The method according to claim 9, wherein, The catalyst has a BET specific surface area of ​​18-23 m². 2 ·g -1 .

11. The method according to any one of claims 1-3, wherein, The support is selected from at least one of SiO2, Al2O3, TiO2, ZrO2, MgO and molecular sieve.

12. The method according to claim 11, wherein, The carrier is SiO2.

13. The method according to claim 1, wherein, The method for preparing the catalyst includes: (1) Mix the vanadium source, reducing agent and first solvent to prepare solution A; (2) First, add boron source and organic acid additive to the second solvent, then add bismuth source to it to obtain solution B; (3) After mixing solution A and solution B, add source X and source Y to dissolve the prepared solution, and then add it to the carrier source to obtain mixed slurry L; (4) The mixed slurry L is heated and concentrated to prepare a slurry; (5) The slurry obtained in step (4) is spray-dried and shaped, and then calcined to obtain the catalyst.

14. The method according to claim 13, wherein, The organic acid auxiliary agent is selected from at least one of lactic acid, tartaric acid, citric acid, and methanesulfonic acid; and / or The reducing agent is selected from at least one of oxalic acid monohydrate, formic acid, citric acid, and hydroxylamine hydrochloride.

15. The method according to claim 14, wherein, The organic acid auxiliary is citric acid; and / or The reducing agent is oxalic acid monohydrate.

16. The method according to any one of claims 13-15, wherein, The molar ratio of the amount of reducing agent added in step (1) to the amount of vanadium source added (calculated as vanadium) is 1~1.25:1; and / or The molar ratio of the amount of organic acid auxiliary agent added in step (2) to the amount of bismuth source added (calculated as bismuth) is 0.3~1:1; and / or The solid content of the slurry in step (4) is 30wt%~65wt%.

17. The method according to any one of claims 13-15, wherein, The conditions for spray drying molding include: gas inlet temperature 350-400°C, outlet temperature 150-200°C, and centrifugal nozzle speed 4000-5000 rpm; and / or The calcination conditions include: a calcination temperature of 500-700°C and a calcination time of 6-15 hours; and / or The conditions for the first mixing include: a temperature of 80-90°C; and / or The conditions for the second mixing include a temperature of 80-90°C.

18. The method according to claim 1, wherein, The conditions for the contact reaction include: The reaction temperature is 320~450°C, and / or the reaction pressure is 101kPa-160kPa, and / or the reaction time is 4h-10h; and / or The feed molar ratio of ammonia source (calculated as NH3), oxygen source (calculated as O2), and m-xylene feedstock (calculated as m-xylene) is NH3:O2:m-xylene = 1-10:2-9:1; and / or The catalyst loading was 0.052-0.082 h⁻¹. -1 ; and / or The ammonia source is ammonia gas; and / or The oxygen source is air.

19. The method according to claim 18, wherein, The conditions for the contact reaction include: the feed molar ratio of ammonia source (NH3), oxygen source (O2), and m-xylene feedstock (m-xylene) is NH3:O2:m-xylene = 4-10:3-9:1.

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