阅读说明：本技术 一种芳烃氨氧化流化床催化剂的制备方法 (Preparation method of aromatic hydrocarbon ammoxidation fluidized bed catalyst ) 是由 曾炜 顾龙勤 陈亮 王丹柳 方敏 于 2019-09-24 设计创作，主要内容包括：本发明公开了一种芳烃氨氧化流化床催化剂的制备方法,包括如下步骤：S1.配制包含活性组分化合物和含硅载体I的混合液；S2.对步骤S1的混合液进行喷雾干燥处理,得到第一催化剂颗粒；S3.配制包含步骤S2得到的第一催化剂颗粒、表面活性分散剂和含硅载体II的混合液；S4.对步骤S3的混合液进行喷雾干燥处理,得到第二催化剂颗粒；S5.对所述第二催化剂颗粒进行焙烧处理,得到催化剂。通过本发明制备方法制备的催化剂,具有较佳的耐磨性,同时保持了较好的催化活性,能有效的降低芳烃氨氧化过程中的催化剂消耗,保持芳烃氨氧化生成的稳定进行。(The invention discloses a preparation method of an aromatic ammoxidation fluidized bed catalyst, which comprises the following steps: s1, preparing a mixed solution containing an active component compound and a silicon-containing carrier I; s2, carrying out spray drying treatment on the mixed liquor obtained in the step S1 to obtain first catalyst particles; s3, preparing a mixed solution containing the first catalyst particles obtained in the step S2, a surface active dispersant and a silicon-containing carrier II; s4, carrying out spray drying treatment on the mixed liquor obtained in the step S3 to obtain second catalyst particles; and S5, roasting the second catalyst particles to obtain the catalyst. The catalyst prepared by the preparation method has better wear resistance, simultaneously keeps better catalytic activity, can effectively reduce the catalyst consumption in the ammoxidation process of the aromatic hydrocarbon, and keeps the stable ammoxidation generation of the aromatic hydrocarbon.)

1. A preparation method of an aromatic ammoxidation fluidized bed catalyst comprises the following steps:

s1, preparing a mixed solution containing an active component compound and a silicon-containing carrier I;

s2, carrying out spray drying treatment on the mixed liquor obtained in the step S1 to obtain first catalyst particles;

s3, preparing a mixed solution containing the first catalyst particles obtained in the step S2, a surface active dispersant and a silicon-containing carrier II;

s4, carrying out spray drying treatment on the mixed liquor obtained in the step S3 to obtain second catalyst particles;

and S5, roasting the second catalyst particles to obtain the catalyst.

2. The method according to claim 1, wherein the active component compound comprises an oxide of an active component, preferably wherein the active component comprises vanadium, at least one element selected from Cr, Na, Mg, K, La, Ce, Ti, Mo, Co, Sb, Mn, Ni, Bi, Zn, and at least one element selected from B, P, As, Zr, W.

3. The preparation method according to claim 1 or 2, wherein the silicon-containing carrier I is at least one of a silica sol, a polysiloxane compound and a silicon-containing molecular sieve, preferably a silica sol.

4. The process according to any one of claims 1 to 3, wherein the siliceous support II is a polysilicic acid and/or a polysilicate, preferably a polysilicic acid.

5. The production method according to any one of claims 1 to 4, wherein the weight ratio of the silicon-containing carrier I to the silicon-containing carrier II is (2 to 9): (1-8), preferably (2-6): (1-4).

6. The method according to any one of claims 1 to 5, wherein the surface active dispersant is at least one of polyvinyl alcohol, polyethylene glycol, and carboxymethyl cellulose.

7. The production method according to any one of claims 1 to 6, wherein the first catalyst particles have an evaluation particle diameter of 20 to 60 μm, and the second catalyst particles have an average particle diameter of 30 to 80 μm.

8. The method as claimed in any one of claims 1 to 7, wherein the temperature of the spray drying in the step S2 is 150-400 ℃, the temperature of the spray drying in the step S4 is 200-450 ℃, and the temperature of the roasting treatment in the step S5 is 300-600 ℃.

9. The aromatic ammoxidation fluidized bed catalyst prepared by the process according to any one of claims 1 to 8, which has an attrition rate of 1.1% or less.

10. Use of the catalyst of claim 9 in the ammoxidation of aromatic hydrocarbons to produce aromatic nitriles.

Technical Field

The invention relates to a preparation method of an aromatic ammoxidation fluidized bed catalyst, in particular to a preparation method of a high-wear-resistance aromatic ammoxidation fluidized bed catalyst, a catalyst prepared by the method and application thereof.

Background

The arylnitrile is an important fine chemical, can be used for synthesizing various synthetic intermediates so as to produce medicines, pesticides, dyes, special materials and the like, and has wide application. For example, the important intermediate 2-cyano-4-nitroaniline of the multipurpose azo disperse dye can be prepared by carrying out nitration and ammonolysis reaction on o-chlorobenzonitrile; the biphenyl compound synthesized with halogenated benzene is used for preparing non-peptide angiotensin, and can also be used for preparing various anti-inflammatory and antibacterial drugs; the m-phthalonitrile can be used for preparing a high-efficiency low-toxicity bactericide tetrachloro-isophthalonitrile through chlorination reaction, and the m-xylylenediamine prepared through hydrogenation reaction can be used for producing a temperature-resistant epoxy resin curing agent and synthesizing special nylon and polyurethane; the benzonitrile can react with dicyandiamide to generate benzoguanamine which is used for producing metal coatings, decorative boards, coloring agents and printing ink, and is a high-boiling-point polar organic solvent with excellent performance.

The production of the aromatic nitrile comprises methods such as chemical synthesis, gas phase ammoxidation and the like, wherein the aromatic hydrocarbon, ammonia and air are subjected to gas phase ammoxidation to synthesize the aromatic nitrile in one step, the process is short, the pollution is less, and the method is the main method for producing the aromatic nitrile at present. The reaction is characterized in that the main and side reactions are strong exothermic reaction processes. The gas phase ammoxidation process of aromatic hydrocarbon mainly comprises fixed bed and fluidized bed processes, wherein the fluid in the fixed bed is in approximate plug flow motion, and the catalyst has higher catalytic efficiency, but the heat transfer performance is poorer, the amplification effect is obvious, and the device is difficult to enlarge; the fluidized bed has the advantages of high heat and mass transfer efficiency, easy large-scale production and the like, but has higher requirements on the physical and chemical properties of the catalyst and the fluidization quality control in the reactor.

Among fluidized bed catalysts for preparing aromatic nitrile by ammoxidation of aromatic hydrocarbon, the V-series catalyst is the most effective catalytic system, such as V-P, V-Cr and the like, and is usually prepared into spherical particles with different particle sizes by taking alumina, silicon carbide and silicon oxide as carriers to be applied in a fluidized bed reactor. Early catalysts generally use a V-P, V-Cr composite system with simple composition as a catalyst, and generally have the problem of low selectivity of aromatic nitrile. In recent years, multi-component V-series catalysts are mostly adopted in the production of the aromatic nitrile fluidized bed catalysts, so that the selectivity of the aromatic nitrile is improved to a certain extent.

For the ammoxidation catalyst of aromatic hydrocarbon, various research patents have been published, such as CN99113575.X relating to a fluidized bed catalyst for preparing isophthalonitrile by ammoxidation of m-xylene, and CN02137455.4 relating to a method for preparing terephthalonitrile. CN201010147809.9 relates to an antimony-containing ammoxidation catalyst. CN201210240053.1 relates to a method for preparing o-chlorobenzonitrile.

Although the above invention discusses the activity and selectivity of the fluidized bed catalyst for ammoxidation of aromatic hydrocarbon, the attrition resistance of the catalyst is mentioned. In the ammoxidation production of aromatic hydrocarbon, the characteristic of a fluidized bed reactor determines that the fluidized bed reactor has higher requirements on the wear resistance of a catalyst, the poor wear resistance of the catalyst can cause the problems of reduced fluidization quality in the reactor, large loss amount of the catalyst, reduced stability and the like, frequent catalyst addition and replacement can greatly increase the cost, and the industrial production of the ammoxidation of the aromatic hydrocarbon is seriously influenced. US 6429330 discloses an ammoxidation catalyst for aromatic hydrocarbons, which comprises V-Cr-Sb-Fe-B-Mo as main component and Fe and Sb as elements, and has optimal wear resistance and abrasion rate of about 2.1-2.6%. CN103896807 discloses a fine fluidized bed catalyst for preparing terephthalonitrile, which adopts V-Cr-P-B-Mo-Co-K as main components, and the best abrasion rate can reach 1.5% -1.6%.

The catalysts reported in the above documents have improved the attrition resistance by using attrition resistant carriers and adding additives such as Fe, Sb, P, etc., but the attrition rate has not yet reached a satisfactory level. For the aromatic hydrocarbon ammoxidation fluidized bed catalyst with high price, how to further improve the wear resistance of the catalyst and ensure the activity yield of the catalyst simultaneously has important significance for improving the economic and technical levels of the aromatic hydrocarbon ammoxidation catalyst.

The existing aromatic hydrocarbon ammoxidation catalyst usually adopts vanadium-containing combined oxide as an active component, but the active component often has the problems of high activity, poor strength and difficult forming, so a carrier is often added in the catalyst to improve the strength, wear resistance and overall performance of the catalyst. Silicon oxide is therefore an important choice for its good strength, low cost and relative inertness itself. In the existing research, a technical scheme that silicon oxide is used as a carrier and an active component is impregnated on the carrier to obtain an active catalyst is provided, but the active component of the impregnated catalyst is often distributed on the outer layer of the catalyst, and if the outer layer is abraded, the performance of the catalyst is possibly reduced and even inactivated, and the problem is particularly prominent in a fluidized bed reactor in which the catalyst is in a motion state. Therefore, fluidized bed catalysts are more suitable for preparing active catalysts by mixing silicon oxide with active components. The catalyst with higher strength can be obtained by adopting the conventional schemes such as silica sol, but for the vanadium oxide catalyst with lower self-strength, the strength of the catalyst obtained by the existing scheme adopting the silica sol can not be satisfactory. The aromatic ammoxidation catalyst usually has a longer catalyst life, so the usage amount of the catalyst is usually increased along with the increase of the wear rate of the catalyst and needs to be frequently supplemented, and the use cost of the whole process is increased. Therefore, on the basis of ensuring the performance of the catalyst, how to further improve the wear resistance of the catalyst has important significance for reducing the use cost and generating the amount of waste catalyst.

The existing improvement scheme comprises adding some catalytic promoter elements into the catalyst formula, but because the addition of the catalytic promoter elements often has important influence on the performance of the catalyst, the addition amount of the catalytic promoter elements is often greatly limited, and the improvement on the wear resistance is limited. The addition of some other, more strong siliceous supports is another solution, but the use of several different supports presents the problem of making the catalyst more homogeneous.

Disclosure of Invention

The invention aims to provide a preparation method of an aromatic hydrocarbon ammoxidation fluidized bed catalyst with improved wear resistance, a catalyst prepared by the method and application thereof, aiming at the problems of poor wear resistance, high loss and insufficient catalyst selectivity of the catalyst in the prior art. The catalyst prepared by the preparation method has better wear resistance, simultaneously keeps better catalytic activity, can effectively reduce the catalyst consumption in the ammoxidation process of the aromatic hydrocarbon, and keeps the stable ammoxidation generation of the aromatic hydrocarbon.

According to one aspect of the invention, a preparation method of an aromatic hydrocarbon ammoxidation fluidized bed catalyst is provided, which comprises the following steps:

s1, preparing a mixed solution containing an active component compound and a silicon-containing carrier I;

s2, carrying out spray drying treatment on the mixed liquor obtained in the step S1 to obtain first catalyst particles;

s3, preparing a mixed solution containing the first catalyst particles obtained in the step S2, a surface active dispersant and a silicon-containing carrier II;

s4, carrying out spray drying treatment on the mixed liquor obtained in the step S3 to obtain second catalyst particles;

and S5, roasting the second catalyst particles to obtain the catalyst.

According to a preferred embodiment of the invention, the weight of the siliceous support in the catalyst is between 30% and 70% of the total weight of the catalyst.

According to a preferred embodiment of the invention, the active component compound comprises an oxide of an active component, preferably the active component comprises vanadium, at least one element selected from Cr, Na, Mg, K, La, Ce, Ti, Mo, Co, Sb, Mn, Ni, Bi, Zn and at least one element selected from B, P, As, Zr, W.

According to a preferred embodiment of the present invention, the silicon-containing carrier I is at least one of a silica sol, a polysiloxane compound and a silicon-containing molecular sieve, and is preferably a silica sol.

According to some embodiments of the invention, the step S1 includes: mixing the active component compound solution with a silicon-containing carrier, and shearing to obtain a suspension.

According to a preferred embodiment of the present invention, the step S2 includes: optionally, the mixed solution of step S1 is concentrated, the solid content of the concentrated solution is 20 wt% to 60 wt%, and then spray-dried to obtain the first catalyst particles.

According to a preferred embodiment of the present invention, the temperature of the spray drying in the step S2 is 150-.

According to a preferred embodiment of the invention, the siliceous support II is polysilicic acid and/or polysilicate, preferably polysilicic acid.

According to a preferred embodiment of the invention, the weight ratio of the silicon containing carrier I and the silicon containing carrier II is (2-9): (1-8), preferably (2-6): (1-4).

According to some embodiments of the present invention, the polysilicic acid is generally prepared before use, for example, by mixing and stirring a metered amount of sodium silicate solution with a dilute sulfuric acid solution and adjusting the pH of the control solution. Polysilicic acid, SiO thereof, used in the present invention₂The weight percentage concentration is 1-10%, and the pH value range is 2-5.

According to some embodiments of the invention, the step S3 includes: mixing the first catalyst particles, the surface active dispersant and the silicon-containing carrier II with water, and shearing to obtain a suspension.

According to a preferred embodiment of the present invention, the step S4 includes: optionally, the mixed solution obtained in step S3 is concentrated, the solid content of the concentrated solution is 20 wt% to 60 wt%, and then spray-dried to obtain second catalyst particles.

According to a preferred embodiment of the present invention, the temperature of the spray drying in the step S4 is 200-450 ℃, preferably 250-450 ℃.

According to a preferred embodiment of the present invention, the surface active dispersant is at least one of polyvinyl alcohol, polyethylene glycol, and carboxymethyl cellulose.

According to a preferred embodiment of the invention, the first catalyst particles have an estimated particle size of 20 to 60 μm and the second catalyst particles have an average particle size of 30 to 80 μm.

According to a preferred embodiment of the present invention, the temperature of the calcination treatment in the step S5 is 300-600 ℃.

Compared with the conventional fluidized bed catalyst synthesis method, the improved preparation method adopts a secondary spraying mode and introduces two functional silicon-containing carriers. Compared with a one-time spraying process, the catalyst has the advantages that the two carriers with different characteristics are added respectively, the uniformity and the stability of the suspension are guaranteed, so that the sprayed catalyst is more uniform, the bonding effect is better, the strength is further improved compared with a single silicon carrier, and the wear resistance of the catalyst is effectively enhanced on the premise of maintaining the performance of the catalyst.

According to another aspect of the present invention, there is provided the aromatic ammoxidation fluidized bed catalyst prepared by the above preparation method, wherein the attrition rate is less than 1.1%, and the average particle size of the catalyst is 30 to 80 μm. The abrasion rate was measured using a test method in accordance with ASTM D5757-00 (relative abrasion characteristics of powder catalysts are judged by air jet abrasion) and is reported in weight percent per hour. The average particle size can be determined by a laser particle sizer.

According to a preferred embodiment of the invention, the weight of the siliceous support in the catalyst is between 30% and 70% of the total weight of the catalyst.

According to another aspect of the invention, there is provided the use of the above catalyst in the ammoxidation of an aromatic hydrocarbon to produce an aromatic nitrile.

According to a preferred embodiment of the invention, said application comprises reacting an aromatic hydrocarbon feedstock, ammonia gas and an oxygen-containing gas in the presence of the above-mentioned catalyst to obtain an aromatic nitrile.

According to some embodiments of the invention, the aromatic hydrocarbon feedstock, ammonia gas, and oxygen-containing gas are in a ratio of (1) to (3-20) to (20-40).

According to some embodiments of the invention, the reaction is carried out in a reaction vesselThe temperature is 390-450 ℃, the reaction pressure is 0-0.2MPa, and the reaction space velocity is 0.02-0.1h^-1(WWH)。

The catalyst obtained by the invention is especially suitable for producing corresponding aromatic nitrile products by ammoxidation of aromatic hydrocarbons of which carbon atoms connected with aromatic rings have hydrogen atoms connected with the carbon atoms. Compared with the conventional catalyst, the catalyst prepared by the technical scheme of the invention has the advantages that the abrasion rate is obviously reduced, and a good technical effect is achieved.

Detailed Description

The present invention will be further illustrated by the following examples, but is not limited to these examples.

[ example 1 ]

182 g of V₂O₅And 152 g Cr₂O₃Adding the mixture into a solution which consists of 980 ml of water and 920 g of oxalic acid and has the temperature of 80-90 ℃, fully stirring for 2 hours, and sequentially adding 37 g of H into the solution₃BO₃23 g of 85 percent phosphoric acid, 17 g of zirconium nitrate and 200 ml of water, and then stirring the mixture continuously to obtain a uniform mixed solution. Adding SiO with the concentration of 40 wt% into the mixed solution₂Is heated with stirring to a uniform and stable suspension at which point the solution solids concentration is concentrated to 35%, and the slurry is spray dried in a spray dryer to give particles having an average particle size of 45 microns.

Adding the catalyst particles into an aqueous solution, heating to 80 deg.C, stirring, adding polyvinyl alcohol (17-99) with pH 3 and SiO 5% of the weight of the catalyst particles₂Polysilicic acid solution with 5 percent of content, SiO in the polysilicic acid₂With SiO in silica sol₂The weight ratio is 1: 9. The solution was stirred well and concentrated to a solids content of about 35%. The resulting slurry was spray-dried again by a spray dryer and then calcined to give an average particle size of 60 μm.

The composition of the active component of the obtained catalyst except oxygen is determined to be VCrP by ICP-AES_0.1B_0.3Zr_0.02. The total weight of the carrier accounts for 50 percent.

The catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, and the raw material is dimethyl isophthalateBenzene, the reaction temperature is 420 ℃, the reaction pressure is 0.06MPa, and the reaction space velocity is 0.06h^-1(WWH) raw material ratio 1 (m-xylene): 10 (ammonia gas): 30 (air). As a result, the conversion of m-xylene was 98.9%, and the molar yield of m-phthalonitrile was 83.8%.

The catalyst was tested using a test method that met the ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) standard, resulting in an attrition rate of 0.91%.

[ example 2 ]

The same preparation method as that of example 1 was adopted, but the composition and the addition amount of the active component were changed, and the active component of the obtained catalyst had a composition of VCrP in addition to oxygen_0.1B_0.3Mo_0.1W_0.05. The total weight of the carrier accounts for 50 percent.

The catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is m-xylene, the reaction temperature is 420 ℃, the reaction pressure is 0.06MPa, and the reaction airspeed is 0.06h^-1(WWH) raw material ratio 1 (m-xylene): 10 (ammonia gas): 30 (air). As a result, the conversion rate of m-xylene was 98.8%, and the molar yield of m-phthalonitrile was 84.5%.

The catalyst was tested using a test method that met the ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) standard, resulting in an attrition rate of 0.97%.

[ example 3 ]

The same preparation method as that of example 1 was adopted, but the amount of the carrier added was changed, and the composition of the active component of the obtained catalyst other than oxygen was VCrP_0.1B_0.3Mo_0.1W_0.05. The total weight of the carrier is 60 percent by SiO₂The ratio of the added silica sol to the added polysilicic acid is 9: 1.

the catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is m-xylene, the reaction temperature is 420 ℃, the reaction pressure is 0.06MPa, and the reaction airspeed is 0.06h^-1(WWH), raw material ratioExample is 1 (m-xylene): 10 (ammonia gas): 30 (air). As a result, the conversion rate of m-xylene was 98.2%, and the molar yield of m-phthalonitrile was 82.4%.

The catalyst was tested using a test method conforming to ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) and the attrition rate was 0.86%.

[ example 4 ]

The same preparation method as that of example 1 was adopted, but the amount of the carrier added was changed, and the composition of the active component of the obtained catalyst other than oxygen was VCrP_0.1B_0.3Mo_0.1W_0.05. The total weight of the carrier is 40 percent by SiO₂The ratio of the added silica sol to the added polysilicic acid is 9: 1.

the catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is m-xylene, the reaction temperature is 420 ℃, the reaction pressure is 0.06MPa, and the reaction airspeed is 0.06h^-1(WWH) raw material ratio 1 (m-xylene): 10 (ammonia gas): 30 (air). As a result, the conversion rate of m-xylene was 98.7%, and the molar yield of m-phthalonitrile was 84.6%.

The catalyst was tested using a test method that met the ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) standard, resulting in an attrition rate of 1.1%.

[ example 5 ]

The same preparation method as that of example 1 was adopted, but the addition ratio of the carrier was changed, and the active component of the obtained catalyst had a composition of VCrP in addition to oxygen_0.1B_0.3Mo_0.1W_0.05. The total weight of the carrier is 50 percent by SiO₂The ratio of the added silica sol to the polysilicic acid is 5: 5.

the catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is m-xylene, the reaction temperature is 420 ℃, the reaction pressure is 0.06MPa, and the reaction airspeed is 0.06h^-1(WWH) raw material ratio 1 (m-xylene): 10 (ammonia gas): 30 (air)). As a result, the conversion of m-xylene was 97.2%, and the molar yield of m-phthalonitrile was 81.5%.

The catalyst was tested using a test method conforming to ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) and the attrition rate was 0.85%.

[ example 6 ]

The same preparation method as that of example 2 was adopted, and the active component of the obtained catalyst, except for oxygen, had the composition of VCrP_0.1B_0.3Mo_0.1W_0.05. The total weight of the carrier accounts for 50 percent.

The catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is p-xylene, the reaction temperature is 410 ℃, the reaction pressure is 0.05MPa, and the reaction airspeed is 0.06h^-1(WWH) raw material ratio 1 (p-xylene): 8 (ammonia gas): 28 (air). The reaction results show that the conversion rate of the p-xylene is 99.5 percent and the molar yield of the terephthalonitrile is 88.7 percent.

The catalyst was tested using a test method that met the ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) standard, resulting in an attrition rate of 0.97%.

[ example 7 ]

The same preparation method as that of example 2 was adopted, and the active component of the obtained catalyst, except for oxygen, had the composition of VCrP_0.1B_0.3Mo_0.1W_0.05. The total weight of the carrier accounts for 50 percent. It is applied to different reactants.

The catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is o-chlorotoluene, the reaction temperature is 410 ℃, the reaction pressure is 0.05MPa, and the reaction airspeed is 0.06h^-1(WWH), the raw material proportion is 1 (o-chlorotoluene): 5 (ammonia gas): 25 (air). The reaction result shows that the conversion rate of o-chlorotoluene is 98.6 percent, and the molar yield of o-chlorobenzonitrile is 81.9 percent.

The catalyst was tested using a test method that met the ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) standard, resulting in an attrition rate of 0.97%.

Comparative example 1

The preparation method is similar to that of the example 1, but the secondary spraying is not adopted, namely, the silica sol, the polysilicic acid and the polyvinyl alcohol are sequentially added into the same mixed slurry, and the product is directly sprayed after concentration to obtain the product. The active component of the obtained catalyst comprises VCrP besides oxygen_0.1B_0.3Zr_0.02. The total weight of the carrier accounts for 50 percent.

The catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is m-xylene, the reaction temperature is 420 ℃, the reaction pressure is 0.06MPa, and the reaction airspeed is 0.06h^-1(WWH) raw material ratio 1 (m-xylene): 10 (ammonia gas): 30 (air). As a result, the conversion rate of m-xylene was 96.8%, and the molar yield of m-phthalonitrile was 80.6%.

The catalyst was tested using a test method that met the ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) standard, resulting in an attrition rate of 1.21%.

Comparative example 2

The product was obtained by using a similar raw material composition as in example 1, but not using the secondary spray and polysilicic acid, and adding only silica sol to the mixed slurry, followed by direct spraying after concentration. The active component of the obtained catalyst comprises VCrP besides oxygen_0.1B_0.3Zr_0.02. The total weight of the carrier accounts for 50 percent.

The catalyst is evaluated in a stainless steel fluidized bed reactor with the diameter of 38 mm multiplied by 1800 mm, the adding amount of the catalyst is 550 g, the raw material is m-xylene, the reaction temperature is 420 ℃, the reaction pressure is 0.06MPa, and the reaction airspeed is 0.06h^-1(WWH) raw material ratio 1 (m-xylene): 10 (ammonia gas): 30 (air). As a result, the conversion rate of m-xylene was 98.6%, and the molar yield of m-phthalonitrile was 82.2%.

The catalyst was tested using a test method that met the ASTM D5757-00 (relative attrition characteristics of powder catalysts as judged by air jet attrition) standard, resulting in an attrition rate of 1.39%.

Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.