Catalysts for the amination of caprolactam to prepare 6-aminohexanonitrile, their preparation methods, and methods for preparing 6-aminohexanonitrile.

Abstract

This disclosure relates to a catalyst for the amination of caprolactam to prepare 6-aminohexanonitrile, a method for preparing the same, and a method for preparing 6-aminohexanonitrile. On a dry basis and based on the total weight of the catalyst, the catalyst comprises 5-95 wt% of a titanium-containing support, 2-30 wt% of vanadium oxide, 0.5-10 wt% of phosphorus pentoxide, 1-20 wt% of a metal M oxide, and / or 0-5 wt% of an inorganic oxide; wherein the titanium-containing support comprises titanium dioxide and a titanium-containing molecular sieve; the metal M is selected from one or more elements of Group VB, Group VIB, Group VIII, and lanthanum; and the inorganic oxide is selected from one or two of Al₂O₃ and SiO₂. The catalyst provided by this disclosure has high activity and good stability, and can improve the conversion rate of caprolactam and the selectivity of the target product.

Description

Technical Field

[0001] This disclosure relates to the field of 6-aminohexanonitrile preparation technology, specifically to a catalyst for the preparation of 6-aminohexanonitrile by caprolactam amination, a preparation method thereof, and a method for preparing 6-aminohexanonitrile. Background Technology

[0002] 6-Aminohexanonitrile is an important chemical intermediate in the synthesis of hexamethylenediamine, obtained through the catalytic amination of caprolactam. However, there are few reports on the synthesis of hexamethylenediamine from caprolactam, with the earliest reports coming from US2234566 and US2181140. US patent US2234566 reports a process in which caprolactam is synthesized into 6-aminohexanonitrile using silica gel supported copper as a dehydration catalyst at a reaction temperature of 360°C and an ammonia / caprolactam molar ratio of 6. The unreacted caprolactam is separated by distillation, and then the aminohexanonitrile is catalytically hydrogenated to hexamethylenediamine over a nickel or cobalt catalyst. The caprolactam conversion rate is 21.7%, and the yield of 6-aminohexanonitrile is 25%. The yield of hexamethylenediamine is not disclosed in the patent.

[0003] US Patent 3855267 reports a method of passing a mixture of ammonia and caprolactam through an aluminum phosphate catalyst, achieving a selectivity of 87% for 6-aminohexanonitrile under conditions where the ammonia / caprolactam molar ratio is 75–100. Both of these methods for preparing 6-aminohexanonitrile suffer from drawbacks such as low catalyst activity and high energy consumption.

[0004] Chinese invention patent CN107739318A reports a method and apparatus for preparing 6-aminohexanonitrile from caprolactam using a liquid-phase method. While using phosphoric acid or phosphate as a catalyst, and with a reaction temperature around 280℃, the yield is low, estimated at around 50% based on examples. This method suffers from drawbacks such as overly complex catalyst and solvent separation, high energy consumption, and low caprolactam conversion.

[0005] The method for synthesizing 6-aminohexanonitrile from caprolactam reported in Chinese invention patent CN107602416A is almost identical to the method reported in patent US2234566. The reported gas-phase method for preparing 6-aminohexanonitrile from caprolactam involves a reaction temperature of around 350℃, with the contact time between caprolactam and ammonia gas being less than 1 second, making the reaction process difficult to control.

[0006] Studies on the preparation of 6-aminohexanonitrile from caprolactam have revealed that caprolactam and ammonia first undergo an ammoniation ring-opening reaction, followed by dehydration to generate 6-aminohexanonitrile. Currently reported gas-phase systems are all conducted under high temperature and high ammonia / caprolactam molar ratio conditions, where ring-opening and dehydration reactions simultaneously occur on the catalyst surface. Besides generating 6-aminohexanonitrile, 5–15% of cracking deammoniation products and polyamide oligomers are also produced, resulting in low caprolactam conversion and 6-aminohexanonitrile selectivity.

[0007] Therefore, although the technology for preparing 6-aminohexanonitrile by caprolactam amination was studied relatively early, problems such as low catalyst activity and low product yield still exist. Summary of the Invention

[0008] The purpose of this disclosure is to provide a catalyst for the amination of caprolactam to prepare 6-aminohexanonitrile, a method for preparing the catalyst, and a method for preparing 6-aminohexanonitrile. The catalyst provided in this disclosure has higher feed conversion rate and selectivity for the target product 6-aminohexanonitrile when used for the preparation of 6-aminohexanonitrile from caprolactam, and the catalyst has better stability.

[0009] To achieve the above objectives, the first aspect of this disclosure provides a catalyst for the amination of caprolactam to prepare 6-aminohexanonitrile, wherein, on a dry basis and based on the total weight of the catalyst, the catalyst comprises 5-95 wt% of a titanium-containing support, 2-30 wt% of vanadium oxide, 0.5-10 wt% of phosphorus pentoxide, 1-20 wt% of a metal M oxide, and / or 0-5 wt% of an inorganic oxide; wherein the titanium-containing support comprises titanium dioxide and a titanium-containing molecular sieve; the metal M is selected from one or more of elements in groups VB, VIB, VIII, and lanthanum; and the inorganic oxide is selected from one or two of Al2O3 and SiO2.

[0010] Optionally, on a dry basis and based on the total weight of the catalyst, the catalyst comprises 30-90 wt% of a titanium-containing support, 4-15 wt% of vanadium oxide, 1-5 wt% of phosphorus pentoxide, 2-10 wt% of M oxide and / or 0.1-2 wt% of inorganic oxide.

[0011] Optionally, the titanium-containing support includes one or both of titanium dioxide and titanium-containing molecular sieves; preferably, the titanium-containing molecular sieve includes titanium-silicon molecular sieves; the titanium-silicon molecular sieves are selected from one or more of HTS, TS-1 molecular sieves, TS-2 and TS-48 molecular sieves.

[0012] Optionally, the metal M is selected from one or more of tungsten, molybdenum, chromium, zinc, manganese, lanthanum, zirconium and iron; preferably it is selected from one or more of tungsten, molybdenum and chromium; more preferably it is selected from one or two of molybdenum and tungsten.

[0013] Optionally, the catalyst has a BET specific surface area of ​​50-300 m². 2 / g, with a total pore volume of 0.1-0.4 mL / g and a micropore volume of 0.05-0.2 mL / g; optionally, the shape of the catalyst is selected from one or more of the following: spherical, strip-shaped, cylindrical, ring-shaped, clover-shaped, tetrapetal-shaped, honeycomb-shaped, and butterfly-shaped.

[0014] The second aspect of this disclosure provides a method for preparing a catalyst for the amination of caprolactam to 6-aminohexanonitrile, comprising the following steps:

[0015] S1. A redox reaction is carried out by contacting vanadium source, water and acid; a metal M source, a phosphorus source and a titanium-containing support are added to the reaction product to obtain a mixture; the mixture is subjected to a first drying treatment to obtain an intermediate solid product.

[0016] S2. The intermediate solid product is subjected to molding, second drying and calcination processes in sequence.

[0017] Optionally, in step S1, the weight ratio of water:vanadium source:acid:metal M source:phosphorus source:titanium-containing support is (0.5-2.0):(0.01-0.2):(0.05-0.5):(0.02-0.5):(0.01-1):1; preferably (0.8-1.6):(0.05-0.15):(0.1-0.3):(0.05-0.3):(0.02-0.5):1.

[0018] Optionally, in step S1, the vanadium source is selected from one or more of ammonium metavanadate, sodium metavanadate, and vanadium pentoxide; the acid is selected from one or more of oxalic acid, citric acid, and nitric acid; the metal M source is selected from one or more of tungsten, molybdenum, chromium, zinc, manganese, lanthanum, and iron; the metal M source is selected from one or more of nitrates, phosphates, and chlorides of metal M; preferably, it is selected from one or more of ammonium molybdate tetrahydrate, sodium tungstate, chromium nitrate, and lanthanum nitrate; and the phosphorus source is selected from one or more of ammonium dihydrogen phosphate, sodium hypophosphite, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

[0019] Optionally, step S1 includes: dissolving the vanadium source in water, then adding the acid to the obtained vanadium source solution to carry out the oxidation reaction, obtaining an oxidation reaction product; adding the metal M source and phosphorus source to the oxidation reaction product, and carrying out a first mixing to obtain a first mixture, optionally, the temperature of the first mixing is 50-100℃ and the time is 60-300 min; adding the titanium-containing support to the first mixture, and carrying out a second mixing to obtain a second mixture, optionally, the temperature of the second mixing is 30-80℃ and the time is 30-300 min; subjecting the second mixture to the first drying treatment, and grinding the obtained product to obtain the intermediate solid product; optionally, the drying temperature of the first drying treatment is 80-150℃.

[0020] Optionally, the molding process in step S2 is extrusion molding, and step S2 further includes: extruding and mixing the intermediate solid product with a pore expander and an additive, and then sequentially performing the molding process, the second drying process, and the calcination process; or the molding process in step S2 is ball rolling molding, and step S2 further includes: mixing the intermediate solid product with an inorganic oxide source, and then sequentially performing the molding process, the second drying process, and the calcination process.

[0021] Optionally, on a dry basis and based on the added weight of the titanium-containing carrier, the amount of the pore-expanding agent is 0.5-10% by weight, preferably 1-5% by weight; the amount of the extrusion aid is 0.5-4% by weight, preferably 0.5-2% by weight; and on a dry basis and based on the added weight of the titanium-containing carrier, the amount of the inorganic oxide source is 0.1-5% by weight, preferably 0.1-4.0% by weight.

[0022] Optionally, in step S2, the pore-expanding agent is selected from one or more of guar gum powder, paraffin wax, stearic acid, glycerin, starch, polyethylene glycol, polyvinyl alcohol, polyethylene oxide, polyacrylamide, cellulose methyl ether, cellulose, polyol, and graphite; the extrusion aid is selected from one or more of organic acids, inorganic acids, and inorganic bases, preferably, the extrusion aid is selected from one or more of oxalic acid, tartaric acid, citric acid, nitric acid, hydrochloric acid, acetic acid, formic acid, ammonia, sodium hydroxide, and potassium hydroxide; optionally, the inorganic oxide source is added in the form of inorganic oxides or inorganic oxide precursors; preferably, the inorganic oxide is selected from one or two of Al2O3 and SiO2; the inorganic oxide precursor is selected from one or more of aluminum sol, silica sol, and water glass.

[0023] Optionally, in step S2, the conditions for the second drying treatment include: a drying temperature of 80-200℃, preferably 100-150℃; a drying time of 1-10h, preferably 2-4h; and the conditions for calcination include: a calcination temperature of 200-900℃, preferably 500-800℃; and a calcination time of 0.5-10h, preferably 2-8h.

[0024] A third aspect of this disclosure provides a catalyst prepared according to the method described in the second aspect.

[0025] The fourth aspect of this disclosure provides a method for preparing 6-aminohexanonitrile by amination of caprolactam, the method comprising: contacting caprolactam, an amination catalyst and ammonia gas in a reactor to carry out an amination reaction; wherein the amination catalyst comprises the catalyst described in the first or second aspect of this disclosure.

[0026] Optionally, the conditions for the amination reaction include: a reaction temperature of 120-700℃, a weight ratio of ammonia to caprolactam of (0.1-100):1, a partial pressure of ammonia of 0.1-5.0 MPa, and a weight hourly space velocity of caprolactam of 0.1-100 h⁻¹. -1 Optionally, the reactor is a fixed-bed reactor; the fixed-bed reactor includes a catalyst bed, and the catalyst bed includes the catalyst.

[0027] Through the above technical solution, this disclosure provides a catalyst for the amination of caprolactam to 6-aminohexanonitrile, a method for preparing the catalyst, and a method for preparing 6-aminohexanonitrile. The catalyst can effectively improve the conversion rate of caprolactam and the selectivity of the target product 6-aminohexanonitrile during the amination of caprolactam. Furthermore, the catalyst exhibits good stability during the reaction and maintains good catalytic activity even under prolonged reaction conditions. The addition of inorganic oxides to the catalyst further enhances its strength and extends its lifespan. The addition of metal M oxide further improves the conversion rate and selectivity of the target product in the amination of caprolactam to 6-aminohexanonitrile, while reducing the formation of byproducts.

[0028] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Detailed Implementation

[0029] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0030] The first aspect of this disclosure provides a catalyst for the amination of caprolactam to prepare 6-aminohexanonitrile, wherein, on a dry basis and based on the total weight of the catalyst, the catalyst comprises 5-95 wt% of a titanium-containing support, 2-30 wt% of vanadium oxide, 0.5-10 wt% of phosphorus pentoxide, 1-20 wt% of a metal M oxide, and / or 0-5 wt% of an inorganic oxide; wherein the titanium-containing support comprises titanium dioxide and a titanium-containing molecular sieve; the metal M is selected from one or more of the elements of Group VB, Group VIB, Group VIII, and lanthanum; and the inorganic oxide is selected from one or two of Al2O3 and SiO2.

[0031] The catalyst disclosed herein can effectively improve the conversion rate of caprolactam and the selectivity of the target product 6-aminohexanonitrile in the preparation of 6-aminohexanonitrile from caprolactam. Furthermore, the catalyst exhibits good stability during the reaction and maintains good catalytic activity even under prolonged reaction conditions. The addition of inorganic oxides to the catalyst further enhances its strength and extends its lifespan. The inclusion of metal M oxide further improves the conversion rate and selectivity of the target product in the amination of caprolactam to 6-aminohexanonitrile, while reducing the formation of byproducts.

[0032] In a preferred embodiment, the catalyst, on a dry basis and based on the total weight of the catalyst, comprises 30-90 wt% of a titanium-containing support, 4-15 wt% of vanadium oxide, 2-10 wt% of phosphorus pentoxide, 2-10 wt% of M oxide, and / or 1-10 wt% of inorganic oxides. When the content of each component of the catalyst meets the range of this embodiment, the feed conversion rate and target product selectivity in the amination of caprolactam to 6-aminohexanonitrile can be further improved.

[0033] In this disclosure, the content of each component in the catalyst was determined using X-ray fluorescence spectrometry. The content of the titanium support in the catalyst of this disclosure is calculated based on all Ti element oxides obtained from XRF testing.

[0034] In one embodiment, the titanium-containing support comprises one or both of titanium dioxide and titanium-containing molecular sieves; on a dry basis, the weight ratio of titanium dioxide to titanium-containing molecular sieves in the titanium-containing support is 1:(0.01-10), preferably 1:(0.1-5). In this disclosure, the weight ratio of titanium dioxide to titanium-containing molecular sieves is calculated based on the mass ratio of the two raw materials added during the preparation process.

[0035] According to this disclosure, titanium dioxide is well known to those skilled in the art, and when used as a support for catalytic materials, rutile and anatase titanium dioxide can be used, with rutile being preferred.

[0036] According to this disclosure, titanium-containing molecular sieves are well known to those skilled in the art, including titanium-silicon molecular sieves; the titanium-silicon molecular sieves are selected from one or more of TS-1, TS-2 and TS-48 molecular sieves.

[0037] In one embodiment, the metal M is selected from one or more of tungsten, molybdenum, chromium, zinc, manganese, lanthanum and iron; preferably selected from one or more of tungsten, molybdenum and chromium, and more preferably selected from one or two of molybdenum and tungsten.

[0038] In one embodiment, the catalyst has a BET specific surface area of ​​50-300 m². 2 / g, preferably 70-130m 2 / g; the total pore volume is 0.1-0.4 mL / g, preferably 0.1-0.25 mL / g; the micropore volume is 0.05-0.2 mL / g, preferably 0.05-0.15 mL / g. In one embodiment, the catalyst is a granular, molded catalyst, the shape of which is selected from one or more of the following: spherical, strip-shaped, cylindrical, ring-shaped, clover-shaped, four-leaf-shaped, honeycomb-shaped, and butterfly-shaped. Preferably, it is strip-shaped or a small sphere with a diameter of 0.5-5.0 mm.

[0039] The catalysts disclosed herein can be used in various reactors, such as fixed-bed reactors, moving-bed reactors, or fluidized-bed reactors.

[0040] The second aspect of this disclosure provides a method for preparing a catalyst for the amination of caprolactam to 6-aminohexanonitrile, characterized by comprising the following steps:

[0041] S1. An oxidation reaction is carried out by contacting a vanadium source, water, and acid; a metal M source, a phosphorus source, and a titanium-containing support are added to the oxidation reaction product to obtain a mixture; the mixture is subjected to a first drying treatment to obtain an intermediate solid product.

[0042] S2. The intermediate solid product is subjected to molding, second drying and calcination processes in sequence.

[0043] This disclosure first involves oxidizing a vanadium source with an acid to obtain an oxidation product (e.g., oxidizing a vanadium source with oxalic acid to obtain vanadium oxalate). The oxidation product is then mixed with a metal M source, a phosphorus source, and a titanium-containing support. After drying to remove moisture, vanadium oxalate, the metal M source, and the phosphorus source can be loaded onto the titanium-containing support to obtain an intermediate solid product.

[0044] In one embodiment, in step S1, the weight ratio of water:vanadium source:acid:metal M source:phosphorus source:titanium-containing support is (0.5-2.0):(0.01-0.2):(0.05-0.5):(0.02-0.5):(0.01-1):1; preferably (0.8-1.6):(0.05-0.15):(0.1-0.3):(0.05-0.3):(0.02-0.5):1. The catalyst prepared using the preferred raw material mass ratio provided in this disclosure exhibits higher reactivity, achieving higher raw material conversion and target product selectivity. The titanium-containing support is calculated based on the total weight of added titanium dioxide and titanium-containing molecular sieves.

[0045] In one embodiment, in step S1, the vanadium source is selected from one or more of ammonium metavanadate, sodium metavanadate, and vanadium pentoxide; the acid is selected from one or more of oxalic acid, citric acid, and nitric acid.

[0046] The metal M source is selected from one or more of the nitrate, phosphate and chloride salts of metal M; preferably one or more of ammonium molybdate tetrahydrate, sodium tungstate, chromium nitrate and lanthanum nitrate.

[0047] The phosphorus source is selected from one or more of ammonium dihydrogen phosphate, sodium hypophosphite, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

[0048] In one specific embodiment, step S1 includes:

[0049] The vanadium source is dissolved in water, and then the acid is added to the vanadium source solution to carry out the oxidation reaction, thereby obtaining the oxidation reaction product;

[0050] The metal M source and phosphorus source are added to the oxidation reaction product, and a first mixing is performed to obtain a first mixture. Optionally, the temperature of the first mixing is 50-100℃ and the time is 60-300min.

[0051] The titanium-containing support is added to the first mixture, and a second mixing is performed to obtain a second mixture. Optionally, the temperature of the second mixing is 30-80℃, and the time is 30-300 min. The second mixture is then subjected to the first drying treatment, and the resulting product is ground to obtain the intermediate solid product. Optionally, the drying temperature of the first drying treatment is 80-150℃. Optionally, the particles can be ground to a maximum particle size of less than 30 μm. The particle size is determined using a laser particle size analyzer.

[0052] In one embodiment, in step S2, the amount of the pore-expanding agent added is 0.5-10% by weight, preferably 1-5% by weight, on a dry basis and based on the added weight of the titanium-containing carrier; the amount of the extrusion aid added is 0.5-4% by weight, preferably 0.5-2% by weight.

[0053] According to this disclosure, in step S2, the molding process includes extrusion molding and ball forming.

[0054] In one embodiment, when extrusion molding is used, step S2 further includes: extruding and mixing the intermediate solid product with a pore expander and an additive, and then sequentially performing the molding process, the second drying process, and the calcination process.

[0055] In a preferred embodiment, the amount of the pore-expanding agent added is 0.5-10% by weight, preferably 1-5% by weight, on a dry basis and based on the added weight of the titanium-containing carrier; the amount of the extrusion aid added is 0.5-4% by weight, preferably 0.5-2% by weight.

[0056] In one specific embodiment, the pore-expanding agent is selected from one or more of the following: guar gum powder, paraffin wax, stearic acid, glycerin, starch, polyethylene glycol, polyvinyl alcohol, polyethylene oxide, polyacrylamide, cellulose methyl ether, cellulose, polyol, and graphite.

[0057] The extrusion aid is selected from one or more of oxalic acid, tartaric acid, citric acid, nitric acid, hydrochloric acid, acetic acid, formic acid, ammonia, sodium hydroxide, and potassium hydroxide. In step S2, this disclosure adds a pore-expanding agent and an extrusion aid, which facilitates the catalyst forming process and increases the pore size of the catalyst.

[0058] In another embodiment, when ball rolling is used, step S2 further includes: mixing the intermediate solid product with an inorganic oxide source, and then sequentially performing the molding process, the second drying process, and the calcination process.

[0059] According to this disclosure, inorganic oxides are used as binders to bind titanium-containing supports and vanadium oxide and metal M oxide powder particles together during extrusion, thereby improving the strength and lifespan of the catalyst.

[0060] In a preferred embodiment, the amount of inorganic oxide source added is 0.1-5% by weight, preferably 0.1-2.0% by weight, based on a dry basis and the added weight of the titanium-containing carrier. This disclosure adds an appropriate amount of inorganic oxide source to avoid the phenomenon that insufficient addition of inorganic oxide source leads to difficulty in catalyst molding, and even if it is molded, it will break when leaving the molding machine; and also avoids the disadvantage of excessive addition of inorganic oxide source leading to soft and sticky spherical products.

[0061] According to this disclosure, the inorganic oxide source in the catalyst can be added in the form of an inorganic oxide or in the form of its precursor, wherein the inorganic oxide includes one or more of Al2O3, SiO2 and ZrO2.

[0062] The inorganic oxide precursor is selected from one or more of aluminum sol, silica sol, and water glass.

[0063] In this disclosure, inorganic oxides, as inert substances, can withstand the corrosion of strong acids and alkalis, thus preventing the molded particles from shattering during alkaline extraction.

[0064] In a further embodiment, if silica sol is used as a binder, it can be either acidic or alkaline silica sol, which is commercially available or prepared according to any existing technology. Other inorganic oxide precursors with binding properties, well known to those skilled in the art, can also be added during the preparation of the composite catalyst.

[0065] In one embodiment, in step S2, the molding process can be one of extrusion molding, ball rolling molding, and sheet forming.

[0066] The conditions for the second drying process include: a drying temperature of 80-200℃, preferably 100-150℃, and a drying time of 1-10h, preferably 2-4h;

[0067] The calcination conditions include: a calcination temperature of 200-900℃, preferably 500-800℃; and a calcination time of 0.5-10h, preferably 2-8h. According to this disclosure, drying and calcination after extrusion molding can improve the catalyst strength.

[0068] A third aspect of this disclosure provides a catalyst prepared according to the method described in the second aspect.

[0069] The fourth aspect of this disclosure provides a method for preparing 6-aminohexanonitrile by amination of caprolactam, the method comprising: contacting caprolactam, an amination catalyst and ammonia gas in a reactor to carry out an amination reaction; wherein the amination catalyst comprises the catalyst described in the first or third aspect of this disclosure.

[0070] In one specific embodiment, the conditions for the amination reaction include: a reaction temperature of 120-700℃, a weight ratio of ammonia to caprolactam of (0.1-100):1, a partial pressure of ammonia of 0.1-5.0 MPa, and a weight hourly space velocity of caprolactam of 0.1-100 h⁻¹. -1 Preferably, the reaction temperature is 200-350℃, the weight ratio of ammonia to caprolactam is (2-10):1, the partial pressure of ammonia is 0.5-2 MPa, and the weight hourly space velocity of caprolactam is 0.2-10 h⁻¹. -1 .

[0071] According to this disclosure, the reactor is a fixed-bed reactor; the fixed-bed reactor includes a packing layer, the packing layer including the ammoniation catalyst.

[0072] According to this disclosure, the feed gas mixture can be diluted with an inert gas such as nitrogen. The reaction is typically carried out at atmospheric pressure, with the reactant gas discharged from the bottom of the fixed-bed reactor and passing through a cooler into an absorption tower to obtain solid reaction products.

[0073] The method for preparing 6-aminohexanonitrile by amination of caprolactam disclosed herein has a lower reaction temperature, a smaller molar ratio of caprolactam to ammonia, a higher conversion rate of raw materials, and a higher yield of the product 6-aminohexanonitrile, thereby reducing the production cost of 6-aminohexanonitrile.

[0074] The following provides a detailed description of specific embodiments of this disclosure. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit this disclosure.

[0075] Unless otherwise specified, all reagents used in the following examples are commercially available.

[0076] Unless otherwise specified, all pressures in the following examples and comparative examples are gauge pressures.

[0077] The crushing strength of the catalyst was measured on a QCY-602 particle strength tester according to the RIPP-25-90 method in "Analytical Methods for Petrochemical Industry" (Yang Cuiding et al., Science Press, 1990).

[0078] In the following examples, the content of each component in the catalyst was determined using X-ray fluorescence spectrometry.

[0079] The BET specific surface area, total pore volume, and micropore volume of the catalyst were determined using a Micromeritics ASAP-2020 automated adsorption analyzer. The specific surface area was calculated using the two-parameter BET equation, the pore distribution was calculated using the BJH method, and the micropore specific surface area and pore volume were calculated using the t-method.

[0080] Particle size was determined using a Mastersizer2000 laser particle size analyzer.

[0081] The preparation examples provide a catalyst for the amination of caprolactam to prepare 6-aminohexanonitrile.

[0082] Preparation Example 1

[0083] Preparation of vanadium oxalate: Dissolve 40g of ammonium metavanadate in 500g of water, then heat in an 80℃ water bath, slowly add 80g of oxalic acid crystals while stirring, and react at 80℃ for 120min until the color of the slurry changes from yellow to a clear purple solution.

[0084] Then add 80g of ammonium molybdate tetrahydrate and 18g of ammonium dihydrogen phosphate, and continue heating in a water bath for 30 minutes to obtain a mixed solution containing vanadium oxalate, ammonium molybdate and phosphoric acid.

[0085] The above solution was stirred continuously in a 70°C water bath. Then, 500g of TiO2 (DuPont R900) and 50g of titanium silicate molecular sieve (Hunan Jianchang product, HTS3 molecular sieve) were added to the solution under continuous stirring, and the mixture was stirred and aged for 4 hours. The resulting product was dried in an oven at 110°C for 4 hours. The dried material was then ground in a grinder for 30 minutes to obtain an intermediate solid product with a maximum particle size of less than 30 micrometers.

[0086] In the above steps, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is 0.909:0.073:0.145:0.145:0.027:1.

[0087] 15g of guar gum powder (purchased from Lankao Plant Gum Factory) and 20g of 20% nitric acid aqueous solution (4g of nitric acid) were added to the intermediate solid product and mixed thoroughly. The amount of guar gum powder added was 2.7% by weight and the amount of nitric acid added was 0.73% by weight, based on the dry basis and the weight of the titanium-containing support. Then, the catalyst was extruded into strips with a diameter of 2.5mm using an extruder, dried at 120℃ for 4h, and then calcined at 750℃ for 4h to obtain the strip catalyst, denoted as CAT-1.

[0088] After drying, the strength of catalyst CAT-1 was measured to be 40 N / cm using a strength tester.

[0089] The catalyst CAT-1 has the following composition: 83.3 wt% TiO2, 4.7 wt% V2O5, 9.9 wt% MoO3, 1.7 wt% P2O5 and 0.4 wt% SiO2 (SiO2 can be derived from titanium silicate molecular sieve).

[0090] Preparation of Comparative Example 1

[0091] The same method as in Preparation Example 1 was used, except that:

[0092] The preparation method used 10g ammonium metavanadate, 20g oxalic acid crystals, 10g ammonium molybdate tetrahydrate, and 2g ammonium dihydrogen phosphate; the remaining process was the same as in the preparation example. The resulting product was designated DCAT-1. The weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing support was 0.909:0.018:0.036:0.018:0.004:1.

[0093] After drying, the strength of catalyst DCAT-1 was measured to be 30 N / cm using a strength tester.

[0094] The catalyst DCAT-1 has the following composition: 96.6 wt% TiO2, 1.4 wt% V2O5, 1.4 wt% MoO3, 0.2 wt% P2O5, and 0.4 wt% SiO2.

[0095] Preparation of Comparative Example 2

[0096] The same method as in Preparation Example 1 was used, except that ammonium molybdate tetrahydrate was not added; the rest of the process was the same as in Preparation Example 1. The resulting product was designated DCAT-2.

[0097] After drying, the strength of catalyst DCAT-2 was measured to be 25 N / cm using a strength tester.

[0098] The catalyst DCAT-2 has the following composition: 92.4 wt% TiO2, 5.3 wt% V2O5, 1.9 wt% P2O5, and 0.4 wt% SiO2.

[0099] Preparation Example 2

[0100] Preparation of vanadium oxalate: Dissolve 40g of ammonium metavanadate in 500g of water, then heat in an 80℃ water bath, slowly add 110g of oxalic acid crystals while stirring, and react at 80℃ for 120min until the color of the slurry changes from yellow to a clear purple solution.

[0101] Then add 80g of ammonium molybdate tetrahydrate and 18g of ammonium dihydrogen phosphate, and continue heating in a water bath for 30 minutes to obtain a mixed aqueous solution containing vanadium oxalate, ammonium molybdate and phosphoric acid.

[0102] The above solution was stirred at 70°C. While stirring continuously, 500g of TiO2 (DuPont R900) and 50g of titanium silicate molecular sieve (Hunan Jianchang product HTS-3) were added, and the mixture was stirred and aged for 4 hours. The resulting product was dried in an oven at 110°C for 4 hours. The dried material was then ground in a grinder for 30 minutes to obtain an intermediate solid product (maximum particle size less than 30 micrometers).

[0103] In the above steps, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is 0.909:0.073:0.2:0.145:0.033:1.

[0104] Then, 20g of aluminum sol (Hunan Jianchang product) was added and mixed thoroughly. The amount of aluminum sol added was 3.6% by weight on a dry basis, based on the weight of the titanium-containing carrier. The mixture was then rotated in a ball mill to form small spherical catalysts. The spherical catalysts with a diameter of 2.0-3.0mm were sieved out, dried at 120℃ for 4 hours, and then calcined at 550℃ for 4 hours to obtain the small spherical catalyst, denoted as CAT-2.

[0105] After drying, the strength of catalyst CAT-2 was measured using a strength tester and found to be greater than 60 N / particle.

[0106] The catalyst CAT-2 has the following composition: 82.8 wt% TiO2, 4.7 wt% V2O5, 9.9 wt% MoO3, 1.7 wt% P2O5, 0.4 wt% SiO2 and 0.5 wt% Al2O3.

[0107] Preparation Example 3

[0108] Preparation of vanadium oxalate: Dissolve 40g of ammonium metavanadate in 500g of water, then heat in an 80℃ water bath, slowly add 110g of oxalic acid crystals while stirring, and carry out the oxidation reaction at 80℃ for 120min until the color of the slurry changes from yellow to purple.

[0109] Then add 40g sodium tungstate and 18g ammonium dihydrogen phosphate, and continue heating in a water bath for 30 minutes to obtain a mixed aqueous solution containing vanadium oxalate, sodium tungstate and phosphoric acid.

[0110] The above solution was stirred continuously at 70°C. Then, 500g of TiO2 (DuPont R900) and 50g of titanium silicate molecular sieve (Hunan Jianchang product, HTS-3 molecular sieve) were added to the solution under continuous stirring, and the mixture was stirred and aged for 4 hours. The resulting product was dried in an oven at 110°C for 4 hours. The dried material was then ground in a grinder for 30 minutes to obtain an intermediate solid product (maximum particle size less than 40 micrometers).

[0111] In the above steps, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is 0.909:0.073:0.2:0.073:0.033:1.

[0112] 15g of guar gum powder and 20g of 20% nitric acid aqueous solution (4g of nitric acid) were added to the intermediate solid product and mixed thoroughly. The amount of guar gum powder added was 2.7% by weight and the amount of nitric acid added was 0.73% by weight, based on the dry basis and the weight of the titanium-containing support. Then, the catalyst was extruded into strips with a diameter of 2.5mm using an extruder, dried at 120℃ for 4h, and then calcined at 600℃ for 8h to obtain the strip catalyst, denoted as CAT-3.

[0113] After drying, the strength of catalyst CAT-3 was measured to be 37 N / cm using a strength tester.

[0114] The catalyst CAT-3 has the following composition: 87.7 wt% TiO2, 5.0 wt% V2O5, 5.1 wt% WO3, 1.8 wt% P2O5 and 0.4 wt% SiO2.

[0115] Preparation Example 4

[0116] Preparation of vanadium oxalate: Dissolve 40g of ammonium metavanadate in 500g of water, then heat in an 80℃ water bath, slowly add 110g of oxalic acid crystals while stirring, and carry out the oxidation reaction at 80℃ for 120min until the color of the slurry changes from yellow to purple.

[0117] Then add 60g of chromium nitrate and 25g of sodium hypophosphite, and continue heating in a water bath for 30 minutes to obtain a mixed aqueous solution containing vanadium oxalate, chromium nitrate and sodium hypophosphite.

[0118] The above solution was stirred continuously at 70°C. Then, 500g of TiO2 (DuPont R900) and 50g of titanium silicate molecular sieve (Hunan Jianchang product, HTS-3 molecular sieve) were added to the solution under continuous stirring, and the mixture was stirred and aged for 4 hours. The resulting product was dried in an oven at 110°C for 4 hours. The dried material was then ground in a grinder for 30 minutes to obtain an intermediate solid product (maximum particle size less than 40 micrometers).

[0119] In the above steps, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is 0.909:0.073:0.2:0.109:0.045:1.

[0120] 15g of guar gum powder and 20g of 20% nitric acid aqueous solution (4g of nitric acid) were added to the intermediate solid product and mixed thoroughly. The amount of guar gum powder added was 2.7% by weight and the amount of nitric acid added was 0.73% by weight, based on the dry basis and the weight of the titanium-containing support. Then, the catalyst was extruded into strips with a diameter of 2.5mm using an extruder, dried at 120℃ for 4h, and then calcined at 750℃ for 8h to obtain the strip catalyst, denoted as CAT-4.

[0121] After drying, the strength of catalyst CAT-4 was measured to be 30 N / cm using a strength tester.

[0122] The catalyst CAT-4 has the following composition: 87.8 wt% TiO2, 5.0 wt% V2O5, 3.6 wt% Cr2O3, 3.2 wt% P2O5 and 0.4 wt% SiO2.

[0123] Preparation Example 5

[0124] Preparation of vanadium oxalate: Dissolve 40g of ammonium metavanadate in 500g of water, then heat in an 80℃ water bath, slowly add 110g of oxalic acid crystals while stirring, and carry out the oxidation reaction at 80℃ for 120min until the color of the slurry changes from yellow to purple.

[0125] Then add 30g of lanthanum nitrate and 30g of sodium hypophosphite, and continue heating in a water bath for 30 minutes to obtain a mixed aqueous solution containing vanadium oxalate, lanthanum nitrate and sodium hypophosphite.

[0126] The above solution was stirred at 70°C. While stirring continuously, 500g of TiO2 (DuPont R900) and 50g of titanium silicate molecular sieve (Hunan Jianchang product, HTS-3 molecular sieve) were added, and the mixture was stirred and aged for 4 hours. The resulting product was dried in an oven at 110°C for 4 hours. The dried material was then ground in a grinder for 30 minutes to obtain an intermediate solid product (maximum particle size less than 40 micrometers).

[0127] In the above steps, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is 0.909:0.073:0.2:0.055:0.055:1.

[0128] 15g of guar gum powder and 20g of 20% nitric acid aqueous solution (4g of nitric acid) were added to the intermediate solid product and mixed thoroughly. The amount of guar gum powder added was 2.7% by weight and the amount of nitric acid added was 0.73% by weight, based on the dry basis and the weight of the titanium-containing support. Then, the catalyst was extruded into strips with a diameter of 2.5mm using an extruder, dried at 120℃ for 4h, and then calcined at 750℃ for 8h to obtain the strip catalyst, denoted as CAT-5.

[0129] After drying, the strength of catalyst CAT-5 was measured to be 30 N / cm using a strength tester.

[0130] The catalyst CAT-5 has the following composition: 88.3 wt% TiO2, 5.0 wt% V2O5, 2.4 wt% La2O3, 3.9 wt% P2O5 and 0.4 wt% SiO2.

[0131] Preparation Example 6

[0132] The preparation method used was the same as in Preparation Example 1, except that 10g of ammonium metavanadate, 30g of oxalic acid crystals, 60g of ammonium molybdate tetrahydrate, and 18g of ammonium dihydrogen phosphate were used; the remaining processes were the same as in Preparation Example 1. The resulting product was designated CAT-6. In this example, the weight ratio of water:vanadium source:acid:metal M source:phosphorus source:titanium-containing support was 0.909:0.018:0.055:0.109:0.033:1.

[0133] After drying, the strength of catalyst CAT-6 was measured to be 13 N / cm using a strength tester.

[0134] The catalyst CAT-6 has the following composition: 77.9 wt% TiO2, 2.4 wt% V2O5, 15.4 wt% MoO3, 3.5 wt% P2O5 and 0.8 wt% SiO2.

[0135] Preparation Example 7

[0136] Preparation of vanadium oxalate: Dissolve 80g of ammonium metavanadate in 600g of water, then heat in a 70℃ water bath, slowly add 140g of oxalic acid crystals while stirring, and carry out the oxidation reaction at 70℃ for 120min until the color of the slurry changes from yellow to purple.

[0137] Then add 90g of ammonium molybdate tetrahydrate and 18g of ammonium dihydrogen phosphate, and continue heating in a water bath for 30 minutes to obtain a mixed aqueous solution containing vanadium oxalate, ammonium molybdate and phosphoric acid.

[0138] The above solution was stirred at 70°C. While stirring continuously, 500g of TiO2 (DuPont R900) and 50g of titanium silicate molecular sieve (Hunan Jianchang product HTS-3 molecular sieve) were added, and the mixture was stirred and aged for 4 hours. The resulting product was dried in an oven at 110°C for 4 hours. The dried material was then ground in a grinder for 30 minutes to obtain an intermediate solid product (maximum particle size less than 40 micrometers).

[0139] In the above steps, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is 1.09:0.145:0.255:0.164:0.033:1.

[0140] Then, 20g of silica sol (purchased from Aldrich, brand name LUDOX AS-40) was added and mixed thoroughly. The amount of silica sol added was 3.6% by weight on a dry basis, based on the weight of the titanium-containing support. The mixture was then spherically rolled in a ball mill to form small spheres of catalyst. The spheres with a diameter of 2.0-3.0mm were sieved out, dried at 120℃ for 4 hours, and then calcined at 550℃ for 8 hours to obtain the small sphere catalyst, designated CAT-7.

[0141] After drying, the strength of catalyst CAT-7 was measured to be 60 N / particle using a strength tester.

[0142] The catalyst CAT-7 has the following composition: 79.5 wt% TiO2, 9.0 wt% V2O5, 8.3 wt% MoO3, 1.6 wt% P2O5, and 1.6 wt% SiO2.

[0143] Preparation Example 8

[0144] The catalyst was prepared using the same method as in Example 1, except that:

[0145] The calcination temperature was 400℃ and the calcination time was 10h. The rest of the process was the same as in Preparation Example 1. The resulting spherical catalyst was designated CAT-8.

[0146] After drying, the strength of catalyst CAT-8 was measured to be 28 N / particle using a strength tester.

[0147] The catalyst CAT-8 has the following composition: 83.1 wt% TiO2, 4.9 wt% V2O5, 9.7 wt% MoO3, 1.9 wt% P2O5 and 0.4 wt% SiO2.

[0148] The structural and performance data of the catalyst products obtained from the above examples and comparative examples are listed in Table 1 below.

[0149] Table 1

[0150]

[0151] The following reaction examples illustrate the effect of using the catalyst provided in this application for the amination of caprolactam to prepare 6-aminohexanonitrile in a fixed-bed reactor.

[0152] Reaction Examples

[0153] 10g of the products obtained in the preparation examples and the comparative preparation examples were respectively loaded into the catalyst. The middle section of a jacketed stainless steel reactor is filled with inert silica sand at both ends. 10 g / h (0.088 mol / h) of caprolactam and 7.5 g / h (0.44 mol / h) of hot ammonia gas (CPL to ammonia molar ratio of 1:5) are metered and thoroughly mixed at 100°C. The caprolactam and ammonia mixture is then brought into contact with a catalyst at a reaction temperature of 280°C, a reaction pressure of 0.5 MPa, and a CPL space velocity of 1.0 h⁻¹. -1 The amination reaction product was deaminated and dehydrated, and then subjected to vacuum distillation to obtain 6-aminohexanonitrile with a purity of 99.0% by weight. In this example, the conversion rate of caprolactam and the selectivity of 6-aminohexanonitrile were measured and calculated at 20 h and 200 h of reaction, respectively. The specific reaction results are listed below.

[0154] Table 2.

[0155]

[0156]

[0157] Table 2

[0158]

[0159]

[0160] As shown in Table 2 above, compared with the DCAT-1 to DCAT-2 prepared in the comparative example, the catalyst prepared by the method provided in this disclosure can achieve higher caprolactam conversion and 6-aminohexanonitrile selectivity in the caprolactam amination reaction; and the changes in caprolactam conversion and 6-aminohexanonitrile selectivity between 200 h and 20 h of reaction are smaller, indicating higher stability.

[0161] Furthermore, comparing CAT-6 with CAT-1 reveals that CAT-1, during its preparation, satisfies the following weight ratio: water: vanadium source: acid: metal M source: phosphorus source: titanium-containing support is (0.8-1.6): (0.05-0.15): (0.1-0.3): (0.05-0.3): (0.02-0.5): 1. CAT-1's composition also satisfies the following: "the catalyst comprises 30-90 wt% titanium-containing support, 4-15 wt% vanadium oxide, 1-5 wt% phosphorus pentoxide, 2-10 wt% M oxide and / or 0.1-2 wt% inorganic oxides." Compared to CAT-6, CAT-1 exhibits higher strength and achieves higher caprolactam conversion and 6-aminohexanoate selectivity in the caprolactam amination reaction.

[0162] Comparing CAT-8 and CAT-1, it can be seen that CAT-1 meets the requirements of "calcination temperature of 500-800℃ and calcination time of 2-8h" during the preparation process. Compared with CAT-8, CAT-1 has higher strength and can achieve higher caprolactam conversion and 6-aminohexanonitrile selectivity in the caprolactam amination reaction.

[0163] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure. For example... It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0164] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A catalyst for the amination of caprolactam to prepare 6-aminohexanonitrile, characterized in that, On a dry basis and based on the total weight of the catalyst, the catalyst comprises 5-95 wt% titanium-containing support, 2-30 wt% vanadium oxide, 0.5-10 wt% phosphorus pentoxide, 1-20 wt% metal M oxide and / or 0-5 wt% inorganic oxide; wherein the titanium-containing support comprises titanium dioxide and titanium-containing molecular sieve; the metal M is selected from one or more of tungsten, molybdenum, chromium, zinc, manganese, lanthanum, zirconium and iron; and the inorganic oxide is selected from one or two of Al2O3 and SiO2.

2. The catalyst according to claim 1, characterized in that, On a dry basis and based on the total weight of the catalyst, the catalyst comprises 30-90 wt% of a titanium-containing support, 4-15 wt% of vanadium oxide, 1-5 wt% of phosphorus pentoxide, 2-10 wt% of metal M oxide and / or 0.1-2 wt% of inorganic oxide.

3. The catalyst according to claim 1, characterized in that, The titanium-containing molecular sieve includes a titanium-silicon molecular sieve; the titanium-silicon molecular sieve is selected from one or more of HTS, TS-1 molecular sieve, TS-2 and TS-48 molecular sieve.

4. The catalyst according to claim 1, characterized in that, The metal M is selected from one or more of tungsten, molybdenum, and chromium.

5. The catalyst according to claim 4, characterized in that, The metal M is selected from one or both of molybdenum and tungsten.

6. The catalyst according to claim 1, characterized in that, The catalyst has a BET specific surface area of ​​50-300 m². 2 / g, with a total pore volume of 0.1-0.4 mL / g and a micropore volume of 0.04-0.2 mL / g.

7. The catalyst according to claim 1, characterized in that, The shape of the catalyst is selected from one or more of the following: spherical, strip-shaped, cylindrical, ring-shaped, clover-shaped, four-leaf-shaped, honeycomb-shaped, and butterfly-shaped.

8. A method for preparing the catalyst for the amination of caprolactam to 6-aminohexanonitrile as described in claim 1, characterized in that, Includes the following steps: S1. A redox reaction is carried out by contacting vanadium source, water and acid; a metal M source, a phosphorus source and a titanium-containing support are added to the reaction product to obtain a mixture; the mixture is subjected to a first drying treatment to obtain an intermediate solid product. S2. The intermediate solid product is subjected to molding, second drying and calcination processes in sequence.

9. The method according to claim 8, characterized in that, In step S1, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is (0.5-2.0):(0.01-0.2):(0.05-0.5):(0.02-0.5):(0.01-1):

1.

10. The method according to claim 9, characterized in that, In step S1, the weight ratio of water:vanadium source: acid: metal M source: phosphorus source: titanium-containing carrier is (0.8-1.6):(0.05-0.15):(0.1-0.3):(0.05-0.3):(0.02-0.5):

1.

11. The method according to claim 8, characterized in that, In step S1, the vanadium source is selected from one or more of ammonium metavanadate, sodium metavanadate, and vanadium pentoxide; The acid is selected from one or more of oxalic acid, citric acid, and nitric acid; The metal M source is selected from one or more of the nitrate, phosphate and chloride salts of metal M; The phosphorus source is selected from one or more of ammonium dihydrogen phosphate, sodium hypophosphite, sodium dihydrogen phosphate, and potassium dihydrogen phosphate.

12. The method according to claim 11, characterized in that, The metal source M is selected from one or more of ammonium molybdate tetrahydrate, sodium tungstate, chromium nitrate, and lanthanum nitrate.

13. The method according to claim 8, characterized in that, Step S1 includes: The vanadium source is dissolved in water, and then the acid is added to the obtained vanadium source solution to carry out the redox reaction, thereby obtaining the redox reaction product; The metal M source and phosphorus source are added to the redox reaction product, and a first mixing is performed to obtain a first mixture. The titanium-containing support is added to the first mixture, and a second mixture is obtained. The second mixture is subjected to the first drying treatment, and the resulting product is ground to obtain the intermediate solid product.

14. The method according to claim 13, characterized in that, The temperature of the first mixing is 50-100℃, and the time is 60-300 min; The second mixing temperature is 30-80℃, and the time is 30-300 min; The drying temperature for the first drying process is 80-150℃.

15. The method according to claim 8, characterized in that, The molding process in step S2 is extrusion molding. Step S2 further includes: mixing the intermediate solid product with a pore expander and an extrusion aid, and then sequentially performing the molding process, the second drying process, and the calcination process; or The molding process described in step S2 is ball rolling molding. Step S2 also includes: mixing the intermediate solid product with an inorganic oxide source, and then sequentially performing the molding process, the second drying process, and the calcination process.

16. The method according to claim 15, characterized in that, On a dry basis and based on the added weight of the titanium-containing carrier, the amount of the pore-expanding agent is 0.5-10% by weight; the amount of the extrusion aid is 0.5-4% by weight. On a dry basis and based on the added weight of the titanium-containing support, the amount of the inorganic oxide source added is 0.1-5% by weight.

17. The method according to claim 16, characterized in that, On a dry basis and based on the added weight of the titanium-containing carrier, the amount of the pore-expanding agent is 1-5% by weight; the amount of the extrusion aid is 0.5-2% by weight. The amount of inorganic oxide source added is 0.1-4.0 by weight, based on a dry basis and the added weight of the titanium-containing support.

18. The method according to claim 15, characterized in that, In step S2, the pore-expanding agent is selected from one or more of the following: guar gum powder, paraffin wax, stearic acid, glycerin, starch, polyethylene glycol, polyvinyl alcohol, polyethylene oxide, polyacrylamide, cellulose methyl ether, cellulose, and graphite. The extrusion aid is selected from one or more of organic acids, inorganic acids, and inorganic bases; The inorganic oxide source is added in the form of inorganic oxides or inorganic oxide precursors.

19. The method according to claim 18, characterized in that, The extrusion aid is selected from one or more of oxalic acid, tartaric acid, citric acid, nitric acid, hydrochloric acid, acetic acid, formic acid, ammonia, sodium hydroxide, and potassium hydroxide.

20. The method according to claim 18, characterized in that, The inorganic oxide is selected from one or both of Al2O3 and SiO2; the inorganic oxide precursor is selected from one or more of aluminum sol, silica sol and water glass.

21. The method according to claim 8, characterized in that, In step S2, the conditions for the second drying process include: a drying temperature of 80-200℃ and a drying time of 1-10 hours. The calcination conditions include: a calcination temperature of 200-900℃ and a calcination time of 0.5-10h.

22. The method according to claim 21, characterized in that, In step S2, the conditions for the second drying process include: a drying temperature of 100-150℃ and a drying time of 2-4 hours. The roasting conditions include: a roasting temperature of 500-800℃ and a roasting time of 2-8 hours.

23. The catalyst prepared by the method according to any one of claims 8-22.

24. A method for preparing 6-aminohexanonitrile by amination of caprolactam, characterized in that, The method includes: Caprolactam, an ammoniation catalyst, and ammonia are contacted in a reactor to carry out an ammoniation reaction; the ammoniation catalyst includes any one of claims 1-7 or the catalyst described in claim 23.

25. The method according to claim 24, characterized in that, The conditions for the amination reaction include: a reaction temperature of 120-700℃, a weight ratio of ammonia to caprolactam of (0.1-100):1, a partial pressure of ammonia of 0.1-5.0 MPa, and a weight hourly space velocity of caprolactam of 0.1-100 h⁻¹. -1 .

26. The method according to claim 24, characterized in that, The reactor is a fixed-bed reactor; the fixed-bed reactor includes a catalyst bed, and the catalyst bed includes the catalyst.

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