Aromatic hydrocarbon ammoxidation catalyst, process for its preparation and use

Abstract

The application provides an aromatic hydrocarbon ammoxidation catalyst and a preparation method and application thereof. The method is as follows: vanadium, chromium and an auxiliary component A are mixed, an organic acid is added, stirring is performed to obtain a solution, a carrier silica sol is added to form slurry 1; an auxiliary component B and an auxiliary component C are dissolved in water, stirring is performed to obtain a solution, a carrier silica sol is added, hydrothermal treatment is performed, slurry 2 is formed; the slurry 1 and the slurry 2 are mixed, heating and evaporation are performed until concentrated slurry is formed; spray drying and high-temperature calcination are performed to prepare a target catalyst. The method solves the problems of low catalyst strength, low reaction activity and poor product yield of the catalyst produced in the prior art when used for ammoxidation reaction, and can be used for industrial production of a catalyst for preparing m-toluic nitrile by ammoxidation of m-xylene.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to an aromatic hydrocarbon ammonia oxidation catalyst, its preparation method, and its application. Background Technology

[0002] Aromatic nitriles are important intermediates, mainly used in the synthesis of various dyes and fragrances. Due to their unique chemical structure and reactivity, aromatic nitriles also have wide applications in organic synthesis, polymer materials, and pharmaceuticals. Typical products of aromatic nitriles include isophthalonitrile, whose tetrachloroisophthalonitrile (chlorothalonil), synthesized by chlorination, is a highly effective and low-toxicity fungicide; and isophthalic diamine (MXDA), obtained by hydrogenation, is a high-performance epoxy resin curing agent and a raw material for polyurethane and nylon resins.

[0003] The simplest and most economical method for producing aromatic nitrile is the gas-phase ammonia oxidation of aromatic hydrocarbons in the presence of a catalyst. The core technology is the catalyst, with V-Cr fluidized bed catalysts being the most widely used in industrial applications. In recent years, with the expansion of the chlorothalonil and MXDA markets, the production scale of isophthalonitrile in my country has also shown rapid growth, leading to increased attention on the research of corresponding catalysts and their production technologies.

[0004] CN106268890A discloses a mixed catalyst for the ammoxidation of aromatics, V 1.0 Cr a A b B c C d M e O x Wherein A is selected from at least one of P, B, Bi, Sb, and As; B is selected from at least one of Mn, Ni, Co, Ti, Sn, Mo, or rare earth elements; C is selected from at least one of alkali metals or alkaline earth metals; and M is selected from at least one of Zr and W. The wear resistance of the catalyst described in this patent has been optimized, with a minimum wear index of 1.15%, but there is still room for improvement.

[0005] CN102527419A discloses a V-Sb catalyst for the ammoxidation of m-xylene to prepare isophthalonitrile. Under the conditions of reaction temperature of 425℃ and reaction pressure of 0.01MPa, the catalyst achieves a xylene conversion rate of 99.2% and an isophthalonitrile yield of 80.8% in a fluidized bed. However, the reaction temperature is too high, the ammonia ratio and oxygen ratio are too high, and the catalyst does not provide feedback on long-term stability.

[0006] CN116237044A discloses a V-Rh catalyst with a molar ratio of m-xylene:ammonia:oxygen of 1:2.1:10.1, a reaction temperature of 360℃ in the ammonia oxidation reactor, a reaction pressure (gauge pressure) of 29 kPa, and a catalyst weight loading of 0.037 h⁻¹. -1 The conversion rate of m-xylene reached 99.9%, and the selectivity of isophthalonitrile reached 99.8%, but it used the extremely expensive precious metal Rh, and the reaction space velocity was low.

[0007] Although the literature has made many attempts to improve the strength, activity and stability of aromatic ammonia oxidation catalysts, it is clear that existing technologies still need to be significantly improved due to their respective limitations. Summary of the Invention

[0008] To address the problems existing in the prior art, one objective of this invention is to provide a novel method for preparing catalysts for the production of aromatic nitriles. This method has the advantages of simple preparation, good catalyst strength, and high activity, yield, and stability when used in ammonia oxidation reactions.

[0009] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0010] A method for preparing an aromatic hydrocarbon ammonia oxidation catalyst, the method comprising the following steps:

[0011] S1: Mix vanadium, chromium, and auxiliary component A, add organic acid, stir to obtain a solution, add carrier silica sol to form slurry 1;

[0012] S2: Dissolve additives B and C in water, stir to obtain a solution, add the carrier silica sol, and perform hydrothermal treatment to form slurry 2;

[0013] S3: Mix slurry 1 and slurry 2, and heat to evaporate until a concentrated slurry is formed;

[0014] S4: Concentrated slurry is spray-dried and calcined at high temperature to produce the target catalyst.

[0015] In one embodiment of the present invention, the acid in S1 is an organic acid, preferably one or more of oxalic acid, tartaric acid, and citric acid. Dissolving the raw materials with various acids during the catalyst preparation process is a conventional technique in the art.

[0016] In one embodiment of the present invention, the auxiliary agent A in S1 provides element A, where A is at least one of molybdenum, bismuth, iron, cobalt, nickel, and tungsten.

[0017] In one embodiment of the present invention, the mass ratio of silica sols S1 and S2 is 20:1 to 1:20, preferably 15:1 to 1:15.

[0018] In one embodiment of the present invention, the hydrothermal treatment temperature in S2 is 100-250°C, preferably 110-200°C.

[0019] In one embodiment of the present invention, the auxiliary agent B in S2 provides element B, wherein B is at least one of lithium, sodium, potassium, rubidium, and cesium.

[0020] In one embodiment of the present invention, the auxiliary agent C in S2 provides element B, and C is at least two of boron, phosphorus, arsenic, tellurium and antimony.

[0021] In one embodiment of the present invention, the evaporation and concentration temperature of S3 is 60-100°C, preferably 70-95°C.

[0022] In one embodiment of the present invention, in step S3, heating and evaporation are performed to form a concentrated slurry with a solid content of 30-60 wt%.

[0023] In one embodiment of the present invention, the temperature of the sprayed slurry in S4 is controlled to be 5-60°C lower than the temperature of the concentrated slurry in S3; preferably, the temperature of the sprayed slurry in S4 is 30-100°C, more preferably 35-95°C. It is further preferred that the slurry temperature in S4 is 5-20°C lower than the evaporation and concentration temperature in S3.

[0024] In one embodiment of the present invention, the viscosity of the slurry in S4 is 150-1000 mPa·s, preferably 150-850 mPa·s.

[0025] In one embodiment of the present invention, the spray inlet temperature in S4 is 180-300°C and the outlet temperature is 90-130°C.

[0026] In one embodiment of the present invention, the calcination temperature in S4 is 500-700°C and the calcination time is 1-15 hours.

[0027] Another object of the present invention is to provide an aromatic hydrocarbon ammonia oxidation catalyst.

[0028] An aromatic hydrocarbon ammonia oxidation catalyst, the catalyst being prepared by the above-described method, and the catalyst having the following chemical formula on an atomic basis:

[0029] V 1.0 Cr a A b B c C d O x / (SiO2) n

[0030] In the formula, A is selected from at least one of molybdenum, bismuth, iron, cobalt, nickel, and tungsten;

[0031] B is selected from at least one of lithium, sodium, potassium, rubidium, and cesium;

[0032] C is selected from at least two of boron, phosphorus, arsenic, tellurium, and antimony;

[0033] Where the value of 'a' ranges from 0.5 to 2.0.

[0034] The value of b ranges from 0.01 to 0.5.

[0035] The value of c ranges from 0.001 to 0.2.

[0036] The value of d ranges from 0.01 to 2.0;

[0037] x is the total number of oxygen atoms required to satisfy the oxidation states of other elements;

[0038] The value of n is chosen such that the content of silica support in the catalyst is 25% to 70% by weight.

[0039] In one embodiment of the invention, the wear index of the catalyst is <1.5%, preferably <1.1%.

[0040] Another object of the present invention is to provide the use of an aromatic hydrocarbon ammonia oxidation catalyst.

[0041] Use of an aromatic hydrocarbon ammoxidation catalyst, wherein the catalyst is obtained by the above preparation method or is the above-described catalyst, the catalyst being used for the ammoxidation of aromatic hydrocarbons to prepare aromatic nitrile, preferably for the preparation of isophthalonitrile from m-xylene.

[0042] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:

[0043] (1) By hydrothermally treating a portion of the support silica sol under the synergistic effect of additives B and C, the resulting catalyst has excellent activity and maintains stable performance during long-term use.

[0044] (2) By controlling the viscosity of the spray-dried slurry and the calcination process during the catalyst preparation process, a high-performance industrial catalyst can be stably manufactured. When applied to the production of aromatic nitrile by ammoxidation of aromatic hydrocarbons, the catalyst exhibits excellent mechanical strength, catalytic activity and stability. Attached Figure Description

[0045] Figure 1 The SEM results are for Example 1;

[0046] Figure 2 The SEM results are for Comparative Example 2;

[0047] Figure 3 The XRD results are for Example 1;

[0048] Figure 4 This is the XRD result for Comparative Example 1. Detailed Implementation

[0049] The method provided by the present invention will be described in further detail below, but the present invention is not limited thereto.

[0050] Test methods

[0051] Testing and characterization of various parameters of the catalyst:

[0052] 1. Method for determining the catalyst attrition index (straight tube method):

[0053] The wear index was determined according to the method in the standard "Determination of Wear Index of Catalytic Cracking Catalyst - Straight Tube Method" Q / TSH3490909 2006.

[0054] 2. Determination of catalyst particle size distribution:

[0055] The particle size distribution was determined using a Bettersize 2000 laser particle size analyzer from Dandong Bettersize, with water as the dispersant.

[0056] 3. Method for determining the viscosity of catalyst slurry

[0057] The measurements were performed using a Shanghai Changji NDJ-1B rotational viscometer, with rotor number 3 selected and a rotation speed of 60 rpm.

[0058] 4. Methods for determining the specific surface area and pore structure information of catalysts

[0059] The BET specific surface area, BJH desorption pore volume, and pore size of the catalyst were determined by N2 physical adsorption method using a Micrometics ASAP 2460 instrument.

[0060] 5. The catalyst was tested using a Hitachi SU3800 scanning electron microscope.

[0061] 6. X-ray powder diffraction (XRD) of the catalyst was performed using a Philips Panalytical X'PertPro rotating target X-ray powder diffractometer.

[0062] 7. Catalyst raw materials

[0063] The metal salt raw materials used in the embodiments or comparative examples of this invention were all purchased from Xilong Chemical Co., Ltd., and ammonium heptamolybdate was purchased from Jinduicheng Molybdenum Co., Ltd. Unless otherwise specified, other raw materials are also commercially available.

[0064] Example

[0065] The formulas for calculating the conversion rate of m-xylene and the selectivity of the target product m-phthalonitrile are as follows:

[0066]

[0067] Example 1

[0068] 1) Catalyst preparation

[0069] 310g vanadium pentoxide, 334g chromium trioxide, 0.32g ammonium heptamolybdate, and 0.49g ferric nitrate were dispersed in 360g water and heated to 70℃. A solution obtained by dissolving 1950g oxalic acid in 1200g water was slowly added while stirring. 1500g of 40wt% silica sol was added and stirred for 1h to obtain slurry 1.

[0070] 0.25g sodium nitrate, 116g boric acid, and 0.76g 85wt% phosphoric acid were dispersed in 300g water, heated to 70℃, and 200g 40wt% silica sol was added with stirring. The mixture was then treated in a hydrothermal reactor at 150℃ for 12h to obtain slurry 2.

[0071] Slurry 1 and slurry 2 were mixed and concentrated by evaporation at 95°C until a concentrated slurry with a solid content of 45 wt% was formed. The concentrated slurry was then cooled to 85°C to obtain a spray-dried slurry with a viscosity of 230 mPa·s.

[0072] The catalyst precursor was obtained by spray drying at an inlet temperature of 250℃ and an outlet temperature of 110℃. The precursor was then placed in a muffle furnace and calcined at 600℃ for 4 hours at a heating rate of 2℃ / min, followed by cooling to room temperature to obtain the ammonia oxidation catalyst. SEM results of the obtained catalyst are shown in the appendix. Figure 1 XRD results are attached. Figure 3 .

[0073] The proportion of active components in the above catalyst is V 1.0 Cr 0.98 Mo 0.05 B 0.55 P 0.06 Fe 0.02 Na 0.01 O x x represents the total number of oxygen atoms required to satisfy the oxidation states of other elements, and the catalyst wear index was determined to be 1.05%.

[0074] 2) Ammoxidation reaction of m-xylene

[0075] 300g of the ammonia oxidation catalyst obtained above was loaded into a fluidized bed reactor for reaction performance evaluation. The feed ratio of m-xylene:ammonia:air was 1:4.7:37, the reaction temperature was 390℃, the reaction pressure was 36kPaG, and the catalyst weight load in the reactor was 0.06h. -1 After 20 hours of reaction, the conversion rate of m-xylene was 98.2% and the selectivity of m-benzonitrile was 81.2%. After 1000 hours of continuous reaction, the conversion rate of m-xylene was 98.9% and the selectivity of m-benzonitrile was 80.9%.

[0076] Comparative Example 1

[0077] Compared with Example 1, the difference is that instead of selectively mixing a portion of the silica sol with additives B and C before hydrothermal treatment, all the silica sol was simply mixed with additives A, B, and C without any hydrothermal treatment steps.

[0078] 1) Catalyst preparation

[0079] 310g vanadium pentoxide, 334g chromium trioxide, 0.32g ammonium heptamolybdate, 0.49g ferric nitrate, 0.25g sodium nitrate, 116g boric acid, and 0.76g 85% phosphoric acid were dispersed in 660g water. The mixture was heated to 70°C, and a solution obtained by dissolving 1950g oxalic acid in 1200g water was slowly added while stirring. 1700g of 40wt% silica sol was then added, and the mixture was stirred for 1 hour to obtain a slurry. The slurry was then evaporated and concentrated at 95°C until a concentrated slurry with a solid content of 45% was formed. The concentrated slurry was cooled to 85°C to obtain a spray-dried slurry with a viscosity of 270 mPa·s.

[0080] The catalyst precursor was obtained by spray drying at an inlet temperature of 250℃ and an outlet temperature of 110℃. The precursor was then placed in a muffle furnace and calcined at 600℃ for 4 hours at a heating rate of 2℃ / min, followed by cooling to room temperature to obtain the ammonia oxidation catalyst. The XRD results of the obtained catalyst are shown in the appendix. Figure 4 .

[0081] The proportion of active components in the above catalyst is V 1.0 Cr 0.98 Mo 0.05 B 0.55 P 0.06 Fe 0.02 Na 0.01 O x x represents the total number of oxygen atoms required to satisfy the oxidation states of other elements, and the catalyst wear index was determined to be 1.06%.

[0082] 2) Ammoxidation reaction of m-xylene

[0083] 300g of the ammonia oxidation catalyst obtained above was loaded into a fluidized bed reactor for reaction performance evaluation. The feed ratio of m-xylene:ammonia:air was 1:4.7:37, the reaction temperature was 390℃, the reaction pressure was 36kPaG, and the catalyst weight load in the reactor was 0.06h. -1 After 20 hours of reaction, the conversion rate of m-xylene was 98.4% and the selectivity of m-benzonitrile was 77.2%. After 1000 hours of continuous reaction, the conversion rate of m-xylene was 99.1% and the selectivity of m-benzonitrile was 74.6%.

[0084] As can be seen from the comparison between Example 1 and Comparative Example 1, the diffraction peak intensity at 2θ = 28° of the catalyst of Comparative Example 1 without hydrothermal treatment is significantly higher, while the diffraction peak intensity of the catalyst of Example 1 with hydrothermal treatment is weaker. The catalyst prepared by the method of the present invention has higher conversion rate, selectivity and long-term stability.

[0085] Example 2

[0086] 1) Catalyst preparation

[0087] 310g vanadium pentoxide, 348g chromium trioxide, and 1.882g ammonium heptamolybdate were dispersed in 360g water and heated to 70℃. A solution obtained by dissolving 1950g oxalic acid in 1200g water was slowly added while stirring. 1300g 40wt% silica sol was added and stirred for 1h to obtain slurry 1.

[0088] 1.25g sodium nitrate, 1.50g potassium nitrate, 97g boric acid, 5.32g antimony acetate, and 290g 80% arsenic acid were dispersed in 300g water, heated to 70℃, and 400g 40% silica sol was added with stirring. The mixture was then treated in a hydrothermal reactor at 120℃ for 24h to obtain slurry 2.

[0089] Slurry 1 and slurry 2 were mixed and concentrated by evaporation at 86°C until a concentrated slurry with a solid content of 45% was formed. The concentrated slurry was then cooled to 35°C to obtain a spray-dried slurry with a viscosity of 450 mPa·s.

[0090] The catalyst precursor was obtained by spray drying at an inlet temperature of 270℃ and an outlet temperature of 105℃. The obtained catalyst precursor was placed in a muffle furnace and calcined at a temperature of 600℃ for 4 hours at a heating rate of 2℃ / min. Finally, it was cooled to room temperature to obtain the ammonia oxidation catalyst.

[0091] The proportion of active components in the above catalyst is V 1.0 Cr 1.02 Mo 0.21 B 0.46 Sb 0.06As 0.48 Na 0.05 K 0.05 O x x represents the total number of oxygen atoms required to satisfy the oxidation states of other elements, and the catalyst attrition index was determined to be 0.95%.

[0092] 2) Ammoxidation reaction of m-xylene

[0093] 300g of the ammonia oxidation catalyst obtained above was loaded into a fluidized bed reactor for reaction performance evaluation. The feed ratio of m-xylene:ammonia:air was 1:4.7:37, the reaction temperature was 390℃, the reaction pressure was 36kPaG, and the catalyst weight load in the reactor was 0.06h. -1 After 20 hours of reaction, the conversion rate of m-xylene was 99.1% and the selectivity of m-benzonitrile was 82.5%. After 1000 hours of continuous reaction, the conversion rate of m-xylene was 99.4% and the selectivity of m-benzonitrile was 82.8%.

[0094] Comparative Example 2

[0095] Compared with Example 1, the difference is that the slurry was spray-dried without cooling after concentration, and the viscosity of the slurry is not within the range of this invention.

[0096] 1) Catalyst preparation

[0097] 310g vanadium pentoxide, 334g chromium trioxide, 0.32g ammonium heptamolybdate, and 0.49g ferric nitrate were dispersed in 360g water and heated to 70℃. A solution obtained by dissolving 1950g oxalic acid in 1200g water was slowly added while stirring. 1500g of 40wt% silica sol was added and stirred for 1h to obtain slurry 1.

[0098] 0.25g sodium nitrate, 116g boric acid, and 0.76g 85wt% phosphoric acid were dispersed in 300g water, heated to 70℃, and 200g 40wt% silica sol was added with stirring. The mixture was then treated in a hydrothermal reactor at 150℃ for 12h to obtain slurry 2.

[0099] Mix slurry 1 and slurry 2, and evaporate and concentrate at 95°C until a concentrated slurry with a solid content of 45% and a viscosity of 127 mP·s is formed.

[0100] The concentrated slurry at 95℃ was spray-dried at an inlet temperature of 250℃ and an outlet temperature of 110℃ to obtain a catalyst precursor. The obtained catalyst precursor was then placed in a muffle furnace and calcined at 600℃ for 4 hours at a heating rate of 2℃ / min, and finally cooled to room temperature to obtain the ammonia oxidation catalyst. The SEM results of the obtained catalyst are shown in the appendix. Figure 2 .

[0101] The proportion of active components in the above catalyst is V 1.0 Cr 0.98 Mo 0.05 B 0.55 P 0.06 Fe 0.02 Na 0.01 O x x represents the total number of oxygen atoms required to satisfy the oxidation states of other elements, and the catalyst wear index was determined to be 2.49%.

[0102] 2) Ammoxidation reaction of m-xylene

[0103] 300g of the ammonia oxidation catalyst obtained above was loaded into a fluidized bed reactor for reaction performance evaluation. The feed ratio of m-xylene:ammonia:air was 1:4.7:37, the reaction temperature was 390℃, the reaction pressure was 36kPaG, and the catalyst weight load in the reactor was 0.06h. -1 After 20 hours of reaction, the conversion rate of m-xylene was 98.3% and the selectivity of m-benzonitrile was 80.6%. After 1000 hours of continuous reaction, the conversion rate of m-xylene was 97.6% and the selectivity of m-benzonitrile was 81.1%.

[0104] As can be seen from the comparison between Example 1 and Comparative Example 2, the temperature of the catalyst spray-dried slurry was not lower than that of the concentrated slurry, and the viscosity of the slurry was slightly lower, which resulted in a large number of cracks on the catalyst surface, a decrease in strength, and damage during long-term operation, leading to a decrease in activity. Therefore, the catalyst prepared by the method described in this invention has better overall performance.

[0105] Example 3

[0106] 1) Catalyst preparation

[0107] 310g of vanadium pentoxide, 533g of chromium trioxide, and 0.179g of ammonium heptamolybdate were dispersed in 520g of water and heated to 70℃. A solution obtained by dissolving 2662g of oxalic acid in 1200g of water was slowly added while stirring. 850g of 40wt% silica sol was added and stirred for 1h to obtain slurry 1.

[0108] Disperse 0.90g potassium nitrate, 30g boric acid, and 5.32g antimony acetate in 200g water, heat to 70℃, add 850g of 40% silica sol while stirring, and treat in a hydrothermal reactor at 190℃ for 8 hours to obtain slurry 2.

[0109] Slurry 1 and slurry 2 were mixed and concentrated by evaporation at 75°C until a concentrated slurry with a solid content of 55% was formed. The concentrated slurry was then cooled to 60°C to obtain a spray-dried slurry with a viscosity of 810 mPa·s.

[0110] The catalyst precursor was obtained by spray drying at an inlet temperature of 290℃ and an outlet temperature of 120℃. The obtained catalyst precursor was placed in a muffle furnace and calcined at a temperature of 650℃ for 2 hours at a heating rate of 2℃ / min. Finally, it was cooled to room temperature to obtain the ammonia oxidation catalyst.

[0111] The proportion of active components in the above catalyst is V 1.0 Cr 1.5 Mo 0.02 B 0.14 Sb 0.06 K 0.03 Ox, where x is the total number of oxygen atoms required to satisfy the valence of other elements, and the catalyst attrition index was measured to be 0.76%.

[0112] 2) Ammoxidation reaction of m-xylene

[0113] 300g of the ammonia oxidation catalyst obtained above was loaded into a fluidized bed reactor for reaction performance evaluation. The feed ratio of m-xylene:ammonia:air was 1:4.7:37, the reaction temperature was 390℃, the reaction pressure was 36kPaG, and the catalyst weight load in the reactor was 0.06h. -1 After 20 hours of reaction, the conversion rate of m-xylene was 98.3% and the selectivity of m-benzonitrile was 83.9%. After 1000 hours of continuous reaction, the conversion rate of m-xylene was 98.5% and the selectivity of m-benzonitrile was 83.6%.

[0114] Example 4

[0115] 1) Catalyst preparation

[0116] 310g vanadium pentoxide, 334g chromium trioxide, 0.32g ammonium heptamolybdate, and 0.49g ferric nitrate were dispersed in 360g water and heated to 70℃. A solution obtained by dissolving 1950g tartaric acid in 1200g water was slowly added while stirring. 500g of 40wt% silica sol was added and stirred for 1h to obtain slurry 1.

[0117] 0.25g sodium nitrate, 116g boric acid, and 0.76g 85wt% phosphoric acid were dispersed in 300g water, heated to 70℃, and 1200g 40wt% silica sol was added with stirring. The mixture was then treated in a hydrothermal reactor at 150℃ for 24h to obtain slurry 2.

[0118] Slurry 1 and slurry 2 were mixed and concentrated by evaporation at 95°C until a concentrated slurry with a solid content of 40% was formed. The concentrated slurry was then cooled to 85°C to obtain a spray-dried slurry with a viscosity of 190 mPa·s.

[0119] The catalyst precursor was obtained by spray drying at an inlet temperature of 200℃ and an outlet temperature of 95℃. The obtained catalyst precursor was placed in a muffle furnace and calcined at a temperature of 550℃ for 12 hours at a heating rate of 2℃ / min. Finally, it was cooled to room temperature to obtain the ammonia oxidation catalyst.

[0120] The proportion of active components in the above catalyst is V 1.0 Cr 1.02 Mo 0.05 B 0.46 Sb 0.06 Fe 0.02 K 0.01 O x x represents the total number of oxygen atoms required to satisfy the oxidation states of other elements, and the catalyst attrition index was determined to be 1.11%.

[0121] 2) Ammoxidation reaction of m-xylene

[0122] 300g of the ammonia oxidation catalyst obtained above was loaded into a fluidized bed reactor for reaction performance evaluation. The feed ratio of m-xylene:ammonia:air was 1:4.7:37, the reaction temperature was 390℃, the reaction pressure was 36kPaG, and the catalyst weight load in the reactor was 0.06h. -1 After 20 hours of reaction, the conversion rate of m-xylene was 97.9% and the selectivity of m-benzonitrile was 84.2%. After 1000 hours of continuous reaction, the conversion rate of m-xylene was 98.1% and the selectivity of m-benzonitrile was 83.9%.

[0123] Although the invention has been described in detail above for illustrative purposes, it should be understood that such detailed description is merely for illustration, and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention, which is defined only by the claims.

Claims

1. A process for the preparation of an aromatic hydrocarbon ammoxidation catalyst characterized by, The method comprises the following steps: S1: mixing vanadium, chromium, and an additive A component, adding an organic acid, stirring to obtain a solution, adding a carrier silica sol to form slurry 1; S2: dissolving an additive B and an additive C component in water, stirring to obtain a solution, adding a carrier silica sol, and hydrothermally treating to form slurry 2; S3: mixing slurry 1 and slurry 2, and heating and evaporating to form a concentrated slurry; S4: spray drying and high-temperature calcination to prepare a target catalyst; In S1, the additive A provides an A element, and the A element is at least one of molybdenum, bismuth, iron, cobalt, nickel, and tungsten; In S2, the additive B provides a B element, and the B element is at least one of lithium, sodium, potassium, rubidium, and cesium; In S2, the additive C provides a C element, and the C element is at least two of boron, phosphorus, arsenic, tellurium, and antimony; The mass ratio of the silica sols in S1 and S2 is 20:1-1:

20.

2. The production method according to claim 1, characterized by, In S1, the organic acid is one or more of oxalic acid, tartaric acid, and citric acid.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the silica sols in S1 and S2 is 15:1-1:

15. And / or, the hydrothermal treatment temperature in S2 is 100-250℃.

4. The production method according to claim 3, characterized by, The hydrothermal treatment temperature in S2 is 110-200℃.

5. The preparation method according to claim 1, characterized in that, The evaporation and concentration temperature in S3 is 60-100℃. And / or, in S3, heating and evaporation are performed to form a concentrated slurry with a solid content of 30-60wt%.

6. The preparation method according to claim 5, characterized in that, The evaporation and concentration temperature in S3 is 70-95℃.

7. The preparation method according to claim 1, characterized in that, In S4, the temperature of the spray slurry is controlled to be 5-60℃ lower than the temperature of the concentrated slurry in S3. And / or, in S4, the viscosity of the slurry is 150-1000mPa·s. And / or, in S4, the inlet temperature of the spray is 180-300℃, and the outlet temperature is 90-130℃. And / or, in S4, the calcination temperature is 500-700℃, and the calcination time is 1-15h.

8. The preparation method according to claim 7, characterized in that, In S4, the temperature of the spray slurry is 35-95℃. And / or, in S4, the viscosity of the slurry is 150-850mPa·s.

9. An aromatic hydrocarbon ammoxidation catalyst, obtainable by the process according to any one of claims 1 to 8, characterized in that, The catalyst has the following chemical formula in terms of atomic ratio: V 1.0 Cr a A b B c C d O x / (SiO2) n In the formula, A is at least one selected from molybdenum, bismuth, iron, cobalt, nickel, and tungsten; B is at least one selected from lithium, sodium, potassium, rubidium, and cesium; C is at least two selected from boron, phosphorus, arsenic, tellurium, and antimony; The value range of a is 0.5-2.0, The value range of b is 0.01-0.5, The value range of c is 0.001-0.2, The value range of d is 0.01-2.0; x is the sum of the number of oxygen atoms required to satisfy the valence of other elements; n is selected such that the content of the carrier silicon dioxide in the catalyst is 25-70wt%.

10. The catalyst of claim 9, wherein The abrasion index of the catalyst is <1.5%.

11. The catalyst of claim 10, wherein The abrasion index of the catalyst is <1.1%.

12. Use of an aromatic hydrocarbon ammoxidation catalyst, which is obtained by the preparation method of any one of claims 1-8 or is the catalyst of any one of claims 9-11, for preparing an aromatic nitrile by aromatic hydrocarbon ammoxidation.

13. The use according to claim 12, wherein the catalyst is used for preparing m-phthalonitrile from m-xylene.

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