Catalyst for preparing aminocapronitrile through caprolactam ammonification and preparation method and application thereof

Abstract

The invention provides a catalyst for preparing aminocapronitrile through caprolactam ammoniation and a preparation method and application thereof, and the method comprises the following steps: 1) carrying out first-step ion exchange on ion exchange resin in a first metal salt solution to obtain a first catalyst precursor; 2) carbonizing the first catalyst precursor, and activating the carbonized catalyst precursor to obtain a second catalyst precursor; 3) treating the second catalyst precursor with a silane coupling agent to obtain a third catalyst precursor; 4) performing hydrothermal treatment on the third catalyst precursor in a glue solution containing a phosphorus source, a silicon source, an aluminum source and organic amine to obtain a fourth catalyst precursor; and 5) carrying out second-step ion exchange on the fourth catalyst precursor in a second metal salt solution to obtain the catalyst. The catalyst disclosed by the invention is high in catalytic activity and long in service life, the catalyst cost and the labor cost can be remarkably reduced in industrial production of aminocapronitrile prepared by caprolactam ammonification, and the economic benefit is improved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a catalyst for preparing aminocapronitrile by amination of caprolactam, and a preparation method and application thereof. Background Art

[0002] 1,6-Hexanediamine (hereinafter referred to as hexanediamine) is one of the three major raw materials for nylon production. As an important chemical intermediate, it can react with adipic acid and sebacic acid to produce nylon 66 and nylon 610 products, and then make various nylon resins, nylon fibers and engineering plastic products. It can also be used to synthesize diisocyanates, epoxy resins or urea-formaldehyde resin curing agents, organic crosslinking agents, etc. As the global demand for nylon products continues to expand, nylon companies are required to continuously expand their production capacity.

[0003] There are many methods for industrial production of hexamethylenediamine, such as butadiene hydrocyanation, acrylonitrile electrolysis, and adipic acid ammoniation dehydration. However, almost all large-scale production methods of hexamethylenediamine start with adiponitrile. Due to the extremely high technical barriers of adiponitrile, the supply of adiponitrile and hexamethylenediamine has always been at a high cost, which is not conducive to the expansion of the production scale of hexamethylenediamine. In contrast, the raw material caprolactam of the caprolactam ammoniation dehydration method has a wide source, simple reaction conditions, low equipment investment, and non-corrosive raw materials, which is suitable for industrial production.

[0004] The process for preparing hexamethylenediamine by caprolactam ammoniation and dehydration comprises the following steps: 1) caprolactam undergoes a ring-opening ammoniation and dehydration reaction with ammonia at high temperature to generate 6-aminocapronitrile (hereinafter referred to as aminocapronitrile); 2) aminocapronitrile is hydrogenated to generate 1,6-hexamethylenediamine. The specific reaction formula is as follows:

[0005]

[0006] Compared with the butadiene hydrocyanation method and the adipic acid ammoniation dehydration method, the caprolactam method has the advantages of short process, low raw material toxicity, low equipment cost and high product yield. Especially in recent years, with the continuous expansion of caprolactam production capacity, the process of preparing 6-aminocapronitrile and then producing hexamethylenediamine using caprolactam as raw material has received widespread attention.

[0007] It should be noted that the process of preparing aminocapronitrile by ammoniation of caprolactam is carried out at a high temperature of about 350°C, and caprolactam itself is a heat-sensitive substance, which is prone to coking and depositing on specific acidic sites on the catalyst surface at high temperatures. In addition, the strong alkaline ammonia gas corrodes the catalyst during the amination reaction, which ultimately leads to catalyst coking and deactivation, reduced service life, decreased reaction selectivity, and decreased raw material conversion rate. These conditions will restrict the improvement of production efficiency and capacity in large-scale industrial production. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention discloses a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, a preparation method and application thereof. The preparation method is simple and easy to scale up, the prepared catalyst has high catalytic activity and long service life, and can significantly reduce the catalyst cost and labor maintenance cost in the industrial production of preparing aminocapronitrile by ammoniation of caprolactam, thereby improving the economic benefit.

[0009] In order to achieve the above technical objectives, on the one hand, the present invention provides a method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, the method comprising the following steps:

[0010] (1) performing a first step of ion exchange in a first metal salt solution using an ion exchange resin to obtain a first catalyst precursor;

[0011] (2) carbonizing the first catalyst precursor and activating the carbonized catalyst precursor to obtain a second catalyst precursor;

[0012] (3) treating the second catalyst precursor with a silane coupling agent to obtain a third catalyst precursor;

[0013] (4) The third catalyst precursor is subjected to hydrothermal treatment in a gel solution containing a phosphorus source, a silicon source, an aluminum source and an organic amine to obtain a fourth catalyst precursor;

[0014] (5) The fourth catalyst precursor is subjected to a second step of ion exchange in a second metal salt solution to obtain the catalyst for preparing aminocapronitrile by amination of caprolactam.

[0015] The above technical solution provides a plurality of technical features for synergistically improving the catalytic activity and service life of the catalyst, specifically:

[0016] Through the ion exchange of step (1) and the high-temperature heat treatment carbonization of step (2), uniformly distributed carbon-supported metal oxides are obtained, which is beneficial to improving the catalytic activity of the catalyst; combined with the activation process, the carbon carrier is endowed with a loose and porous structure, which significantly increases the specific surface area of ​​the catalyst and provides abundant mass transfer channels for the subsequent caprolactam amination reaction. These mass transfer channels are not only beneficial to improving the reaction rate of the catalyst, but also enable the effective discharge of by-products (such as branched amines or oligomers generated by the caprolactam amination reaction), preventing the by-products from staying for a long time and causing the catalyst to coke, thereby improving the life of the catalyst; in addition, the reducing property of the carbon carrier in the activation process can also partially reduce the metal ions, thereby providing a suitable catalytic reaction electron density for the active components of the catalyst, making it easier to form chemical adsorption with caprolactam, making the amination reaction easier to proceed and the reaction speed faster. Further, the silane coupling agent treatment in step (3) forms an active site suitable for the growth of molecular sieves, and after the hydrothermal treatment in step (4), a molecular sieve is formed in the microporous structure inside the catalyst ball, and the molecular sieve is tightly combined with the metal cations uniformly distributed on the carbon carrier to form a metal phosphate active phase inside the molecular sieve. Furthermore, the catalyst is modified by the second step ion exchange in step (5), and the active site of the side reaction of the poisoning of a small amount of alkali metal or alkaline earth metal is loaded, thereby improving the selectivity of the catalyst. Through the coordinated optimization of the above preparation process, the catalyst prepared by the catalyst preparation method of the present invention has the advantages of good catalytic activity and long life, and is suitable for industrial production.

[0017] Based on the above technical solution, the first ion exchange process loads metal cations into the ion exchange resin. In a further example of the present invention, the first ion exchange includes contacting the ion exchange resin with a first metal salt solution.

[0018] The present invention does not limit the type of the ion exchange resin. Those skilled in the art can select a resin that can be used for ion exchange with cations as needed. In a further example of the present invention, the ion exchange resin can be selected as an acidic cation exchange resin, and further can be selected to include one or both of a carboxylic acid cation exchange resin and a sulfonic acid cation exchange resin.

[0019] The present invention is not particularly limited to the shape of the ion exchange resin, and can be effectively applied to anion exchange resins formed into various shapes such as fiber, powder, plate, and film, in addition to commonly used spherical ion exchange resins.

[0020] In a further example of the present invention, the temperature of the first step ion exchange is 20-100° C. and the time is 2-10 h.

[0021] The present invention does not limit the number of times of the first ion exchange. It is understandable that those skilled in the art can choose to perform one ion exchange or multiple ion exchanges in the first ion exchange process according to actual working conditions to achieve the purpose of sufficient ion exchange between metal cations and ion exchange resin. In a further example of the present invention, the number of times of the first ion exchange can be selected from 1 to 5 times.

[0022] Based on the above technical solution, the first metal salt solution is prepared by dissolving the first metal salt in water. In a further example of the present invention, the cation of the first metal salt includes Ni 2+ 、Co 2+ 、Ce 3+ , Fe 3+ Mg 2+ ,La + , Mn 4+ 、Zn 2+ At least one of .

[0023] The present invention does not limit the type of anion of the first metal salt, and any anion type that can make the first metal salt soluble in water is sufficient. In a further example of the present invention, the anion of the first metal salt includes at least one of nitrate, formate, acetate, and benzoate, and those skilled in the art can select a suitable soluble metal salt for preparing the first metal salt solution according to specific working conditions.

[0024] In a further example of the present invention, the mass concentration of the first metal salt solution is 1-10%.

[0025] The present invention does not limit the amount of the first metal salt solution, as long as the first metal cation and the ion exchange resin can be fully exchanged. In the actual process, the ion exchange resin is immersed in the first metal salt solution as a whole, and stirring can be optionally used to promote full contact between the two. In an optional example of the present invention, the first metal salt solution can be recycled.

[0026] Based on the above technical solution, the carbonization process carbonizes the ion exchange resin loaded with the first metal by high temperature heat treatment to obtain a carrier. In a further example of the present invention, the carbonization process in step (2) includes: heat treating the first catalyst precursor in a flowing inert atmosphere.

[0027] The present invention is not limited to the control conditions of the carbonization treatment. In a further example of the present invention, the temperature of the carbonization process can be selected to be 300 to 800° C., and the treatment time can be selected to be 4 to 12 hours.

[0028] Based on the above technical solution, the activation process is to heat treat the carbonized catalyst precursor in an atmosphere containing a specific reaction gas, during which the reaction gas and the carbon carrier are fully contacted and reacted, so that the surface of the carbon carrier is eroded to form a fluffy and porous structure. In a further example of the present invention, the activation process in step (2) includes: heat treating the carbonized first catalyst precursor in an atmosphere containing a reaction gas and an inert gas.

[0029] The present invention does not limit the type of reaction gas, and those skilled in the art can select a suitable reaction gas according to specific working conditions. In a further example of the present invention, the reaction gas includes at least one of water vapor, ethanol vapor, and methanol vapor.

[0030] The activation operation of the present invention is carried out in an inert atmosphere containing a reaction gas, and the progress of the activation process is conveniently regulated by regulating the amount of the inert gas and the reaction gas in the atmosphere. In a further example of the present invention, the molar ratio of the inert gas to the reaction gas in the inert atmosphere is 1 to 10, thereby avoiding an overly fast reaction or an overly low reaction efficiency, and improving the operability of the process.

[0031] The inert gas mentioned in the present invention refers to a gas that does not chemically interact with the reactants, such as nitrogen and gases of the zeroth group elements in the periodic table (such as argon); an inert atmosphere refers to a gas environment composed of gases that do not chemically interact with the reactants, such as a nitrogen atmosphere, or an atmosphere formed by gases of the zeroth group elements in the periodic table (such as argon).

[0032] In a further example of the present invention, the temperature of the activation process is 300-800° C., and the treatment time is 4-12 hours.

[0033] In a further example of the present invention, the activation process further includes switching to an inert atmosphere for purging after the activation is completed; further optionally, the temperature of the purging process is 300-500°C, the processing time is 2-4 hours, and the organic matter generated during the activation process is removed by purging. Further optionally, after the purging process is completed, the second catalyst precursor is slowly cooled to room temperature.

[0034] Based on the above technical solution, it is difficult to directly crystallize the second catalyst precursor to generate a molecular sieve. The silane coupling agent treatment can form an active site suitable for the growth of the molecular sieve on the second catalyst precursor, which is convenient for the subsequent formation of the molecular sieve. In a further example of the present invention, the silane coupling agent treatment in step (3) includes: contacting the second catalyst precursor with a silane coupling agent solution.

[0035] In a further example of the present invention, the silane coupling agent may optionally include one or more of vinyl silane coupling agents, chloroalkyl silane coupling agents, aminoalkyl silane coupling agents, epoxyalkyl silane coupling agents, methacryloyloxyalkyl silane coupling agents, sulfur-containing hydrocarbon silane coupling agents, pseudohalogen silane coupling agents and quaternary ammonium hydrocarbon silane coupling agents. It may further optionally include at least one of KH550, KH570, KH540 and KH792.

[0036] In a further example of the present invention, the concentration of the silane coupling agent solution is 0.5-2.5%; the silane coupling agent solution used in the present invention is an aqueous solution of a silane coupling agent, and its concentration is a mass concentration.

[0037] In a further example of the present invention, the temperature of the silane coupling agent treatment is 30-100°C.

[0038] The present invention does not limit the amount and treatment time of the silane coupling agent solution, as long as the second catalyst precursor is fully in contact with the silane coupling agent solution. In the actual process, the second catalyst precursor is immersed in the silane coupling agent solution as a whole; in an optional example of the present invention, the silane coupling agent solution can be recycled.

[0039] Based on the above technical solution, in step (4), a molecular sieve can be formed in the mass transfer channel of the third catalyst precursor through hydrothermal treatment. The molecular sieve is tightly combined with the metal cations to form a metal phosphate active phase inside the molecular sieve, which is the basis of the catalytic activity of the catalyst.

[0040] The present invention is not limited to the type of the phosphorus source. In a further example of the present invention, in step (4), the phosphorus source includes at least one of phosphoric acid, pyrophosphoric acid, hypophosphorous acid, and ammonium phosphate, and those skilled in the art can select it according to actual needs.

[0041] The present invention does not limit the type of the silicon source. In a further example of the present invention, in step (4), the silicon source includes at least one of silica sol, tetraethyl orthosilicate, fumed silicon oxide, silicic acid, and metasilicic acid. Those skilled in the art can select according to actual needs.

[0042] The present invention is not limited to the type of the aluminum source. In a further example of the present invention, in step (4), the aluminum source includes at least one of 20% aluminum sol (mass content), pseudo-boehmite, sodium aluminate, and γ-alumina. Those skilled in the art can select according to actual needs.

[0043] In addition, the present invention is not limited to the type of organic amine. In a further example of the present invention, in step (4), the organic amine includes at least one of diethylamine, ethylenediamine, ethylamine, n-propylamine, propylenediamine, and triethylamine. Those skilled in the art can select according to actual needs.

[0044] In a further example of the present invention, the mass ratio of the phosphorus source, silicon source and aluminum source can be selected to be 1: (0.5-5): (0.2-2).

[0045] In a further example of the present invention, the mass ratio of the organic amine to the total amount of the phosphorus source, the silicon source and the aluminum source may be 1:(0.5-5).

[0046] In a further example of the present invention, the mass ratio of the third catalyst precursor to the sum of the masses of the silicon source, the aluminum source and the phosphorus source is 1:(1-5).

[0047] In a further example of the present invention, the control conditions of the hydrothermal treatment include: the temperature of the hydrothermal treatment can be selected to be 120 to 200° C., and the treatment time can be selected to be 24 to 72 hours.

[0048] Based on the above technical solution, the fourth catalyst precursor is modified in the second ion exchange process, and the catalyst is loaded with a second metal through ion exchange, thereby poisoning the active sites that cause side reactions during the caprolactam amination reaction, reducing the generation of by-products and improving the selectivity of the catalyst.

[0049] In a further example of the present invention, the second ion exchange step includes: contacting the fourth catalyst precursor with a second metal salt solution.

[0050] In a further example of the present invention, the temperature of the second step ion exchange is 30-100° C. and the time is 2-10 h.

[0051] The present invention does not limit the number of times the second step ion exchange is performed. It is understandable that those skilled in the art can choose to perform one or more ion exchanges in the second step ion exchange process according to actual working conditions. In a further example of the present invention, the number of times the second step ion exchange is performed can be selected from 1 to 5 times.

[0052] In a further example of the present invention, the step (5) further includes washing and calcining the catalyst precursor after the second step of ion exchange; washing can remove the second metal cations not embedded in the catalyst precursor, and calcining can improve the stability of the catalyst structure. Optionally, the calcination temperature is 400 to 800°C, and the calcination time is 4 to 12 hours. Further optionally, between the washing operation and the calcination operation, an operation of drying the catalyst precursor is also included, thereby improving the calcination operability and calcination efficiency.

[0053] Based on the above technical solution, the second metal salt solution in step (5) is prepared by dissolving the second metal salt in water. In a further example of the present invention, the cation of the second metal salt may be an alkali metal and / or an alkaline earth metal. Furthermore, the cation of the second metal salt may include Li + 、Na + , K + 、Be 2+ Mg 2+ , Ca 2+ , Ba 2+ At least one of .

[0054] The present invention does not limit the type of anion of the second metal salt, and any anion type that can make the second metal salt soluble in water is sufficient. In a further example of the present invention, the anion of the second metal salt includes at least one of nitrate, formate, acetate, and benzoate, and those skilled in the art can select a suitable soluble metal salt for preparing the first metal salt solution according to specific working conditions.

[0055] In a further example of the present invention, the mass concentration of the second metal salt is 0.5-5%.

[0056] The present invention does not limit the amount of the second metal salt solution used, and it can be used to allow metal cations to exchange ions with the fourth catalyst precursor. In the actual process, the fourth catalyst precursor is immersed in the second metal salt solution as a whole, and stirring can be used to promote full contact between the two. In an optional example of the present invention, the second metal salt solution can be recycled.

[0057] On the other hand, the present invention provides a catalyst for preparing aminocapronitrile by amination of caprolactam, which is prepared by the preparation method of the above catalyst.

[0058] On the other hand, the present invention proposes the use of the catalyst for preparing aminocapronitrile by ammoniation of caprolactam in preparing aminocapronitrile from caprolactam.

[0059] Compared with the prior art, the beneficial effects of the present invention are as follows: in the preparation method of the catalyst of the present invention, the ion exchange resin loaded with metal cations is carbonized and activated, which significantly increases the specific surface area of ​​the catalyst, provides abundant mass transfer channels for caprolactam amination, increases the catalytic activity of the catalyst to promote the effective removal of by-products, prevents the catalyst from coking and thus extends the service life of the catalyst; through the combination of a silane coupling agent and hydrothermal crystallization, a molecular sieve is combined in the catalyst mass transfer channel to form a reactive site, further enhancing the catalytic performance of the catalyst, and then the conformation of the catalyst is modified by the second step of ion exchange, thereby improving the selectivity of the catalyst. The preparation method of the catalyst of the present invention is simple and easy to scale up, and the prepared catalyst has high catalytic activity and long service life. It can significantly reduce the cost of using the catalyst in the industrial production of caprolactam amination to prepare aminocapronitrile, as well as reduce equipment maintenance and labor costs, thereby improving economic benefits. DETAILED DESCRIPTION

[0060] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are given. However, it should be understood that these embodiments are only used for more detailed description and should not be understood as limiting the present invention in any form, i.e., not intended to limit the scope of protection of the present invention.

[0061] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0062] The terms "first", "second", "third", "fourth", "fifth", "once", "twice", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", "third", "fourth", "fifth", "once", "twice", etc. may explicitly or implicitly include one or more of the feature. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0063] The service life of the catalyst of the present invention is detected by a long-time evaluation method. When the conversion rate of the reaction is lower than 80% of the initial conversion rate, the catalyst is considered to be deactivated.

[0064] The catalyst evaluation method is: using ammonia and caprolactam as raw materials, the catalyst is used to prepare aminocapronitrile in a fixed bed reactor, the reaction temperature is 300-400°C, and the reaction space velocity of caprolactam is 2-8h -1; Among them, the single-pass conversion rate of caprolactam = (1-the percentage of caprolactam content in the reaction solution) × 100%, the yield of aminocapronitrile = the percentage of aminocapronitrile content in the reaction solution / (1-the content of caprolactam in the reaction solution) × 100%.

[0065] Example 1

[0066] A method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, specifically comprising the following steps:

[0067] (1) A mixed solution of ferric nitrate and lanthanum nitrate with a concentration of 2.5% (the ratio of iron to lanthanum in terms of atoms is 2:3) is prepared, and a carboxylic acid type cation exchange resin is immersed in the metal salt solution, heated to 50° C., and treated for 2 hours, and then the resin is taken out, cleaned, and dried. The ion exchange treatment is performed 3 times in total to obtain a first catalyst precursor.

[0068] (2) The first catalyst precursor is placed in a muffle furnace with a controllable atmosphere, nitrogen is introduced, the temperature is raised to 600°C in a flowing atmosphere, and heat treated for 10 hours. The atmosphere is switched to a mixture of ethanol vapor and nitrogen, the ratio of nitrogen to ethanol is 3, the heat treatment temperature is 700°C, and the treatment time is 8 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 400°C, and the heat treatment time is 8 hours. A second catalyst precursor is obtained.

[0069] (3) Prepare a 2.0% KH550 silane coupling agent solution, heat the silane coupling agent solution to 80° C., place the second catalyst precursor in the silane coupling agent solution for treatment, then take out the solid obtained after the treatment, wash it to neutrality, and dry it to obtain a third catalyst precursor.

[0070] (4) 100 g of phosphoric acid, 150 g of fumed silica and 80 g of pseudo-boehmite were added to water respectively, and after being stirred evenly, 150 g of diethylamine and 300 g of n-propylamine were added and stirred until a uniform colloidal liquid was formed, 330 g of the third catalyst precursor was added to the colloidal liquid, and then the colloidal liquid was transferred to a hydrothermal reactor, heated to 180° C., and hydrothermally treated for 48 hours. After the treatment was completed, the catalyst was washed to neutrality and dried to obtain a fourth catalyst precursor.

[0071] (5) Prepare a 2% sodium nitrate solution, heat the solution to 80° C., place the fourth catalyst precursor in the solution, treat for 2 hours, then take out the catalyst precursor, clean it and dry it. This treatment is carried out 3 times in total. After the treatment, calcine the catalyst at 500° C. for 6 hours. The catalyst for preparing aminocapronitrile by ammoniation of caprolactam is obtained.

[0072] Example 2

[0073] A method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, specifically comprising the following steps:

[0074] (1) Prepare a 10% zinc acetate solution, immerse a carboxylic acid type cation exchange resin in the metal salt solution, heat to 100° C., treat for 2 hours, then take out the resin, clean it, and dry it. The ion exchange treatment is performed 5 times in total to obtain a first catalyst precursor.

[0075] (2) The first catalyst precursor is placed in a muffle furnace with a controllable atmosphere, argon is introduced, the temperature is raised to 800°C in a flowing atmosphere, and the heat treatment is performed for 4 hours. The atmosphere is switched to a mixture of methanol and argon, the ratio of argon to methanol is 10, the heat treatment temperature is 900°C, and the treatment time is 4 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 800°C, and the heat treatment time is 4 hours. A second catalyst precursor is obtained.

[0076] (3) Prepare a 2.5% KH570 silane coupling agent solution, heat the silane coupling agent solution to 100° C., place the second catalyst precursor in the silane coupling agent solution for treatment, then take out the solid obtained after the treatment, wash it to neutrality, and dry it to obtain a third catalyst precursor.

[0077] (4) 100 g of pyrophosphoric acid, 500 g of silica sol and 200 g of 20% aluminum sol are added to water respectively, stirred evenly, and then 400 g of ethylamine is added and stirred until a uniform colloidal liquid is formed, 200 g of the third catalyst precursor is added to the colloidal liquid, and then the colloidal liquid is transferred to a hydrothermal reactor, heated to 200° C., and hydrothermally treated for 24 hours. After the treatment is completed, the catalyst is washed to neutrality and dried to obtain a fourth catalyst precursor.

[0078] (5) Prepare a 5% potassium formate solution, heat the solution to 100° C., place the fourth catalyst precursor in the solution, treat for 2 hours, then take out the catalyst precursor, clean it and dry it. This treatment is carried out 3 times in total. After the treatment, calcine the catalyst at 500° C. for 6 hours. The catalyst for preparing aminocapronitrile by ammoniation of caprolactam is obtained.

[0079] Example 3

[0080] A method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, specifically comprising the following steps:

[0081] (1) Prepare a mixed solution of 1% iron benzoate and manganese benzoate (the ratio of iron to manganese in atoms is 1:2), immerse a sulfonic acid type cation exchange resin in the metal salt solution, heat to 20° C., treat for 10 hours, then take out the resin, clean it, and dry it to obtain a first catalyst precursor.

[0082] (2) The first catalyst precursor is placed in a muffle furnace with a controllable atmosphere, argon is introduced, the temperature is raised to 300°C in a flowing atmosphere, and the heat treatment is performed for 12 hours. The atmosphere is switched to a mixture of water vapor and argon, the ratio of argon to water is 1, the heat treatment temperature is 300°C, and the treatment time is 12 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 300°C, and the heat treatment time is 12 hours. A second catalyst precursor is obtained.

[0083] (3) Prepare a 0.5% KH540 silane coupling agent solution, heat the silane coupling agent solution to 30° C., place the heat-treated catalyst in the silane coupling agent solution for treatment, then take out the solid obtained after the treatment, wash it to neutrality, and dry it to obtain a third catalyst precursor.

[0084] (4) 100 g of hypophosphorous acid, 50 g of ethyl orthosilicate and 20 g of sodium aluminate were added to water respectively, and after being stirred evenly, 350 g of ethylamine and 400 g of n-propylamine were added and stirred until a uniform colloidal liquid was formed, 170 g of the third catalyst precursor was added to the colloidal liquid, and the colloidal liquid was transferred to a hydrothermal reactor, heated to 120° C., and hydrothermally treated for 72 hours. After the treatment was completed, the catalyst was washed to neutrality and dried to obtain a fourth catalyst precursor.

[0085] (5) Prepare a 0.5% calcium benzoate solution, heat the solution to 30° C., place the fourth catalyst precursor in the solution, treat for 10 hours, then take out the catalyst precursor, clean it and dry it. This treatment is carried out 5 times in total. After the treatment, calcine the catalyst at 300° C. for 12 hours. The catalyst for preparing aminocapronitrile by ammoniation of caprolactam is obtained.

[0086] Example 4

[0087] A method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, specifically comprising the following steps:

[0088] (1) A mixed solution of cerium formate and magnesium formate with a concentration of 10% (the ratio of cerium to magnesium in terms of atoms is 5:1) is prepared, and a sulfonic acid type cation exchange resin is immersed in the metal salt solution, heated to 100° C., and treated for 2 hours. The resin is then taken out, cleaned, and dried. The ion exchange treatment is performed 5 times in total to obtain a first catalyst precursor.

[0089] (2) The first catalyst precursor is placed in a muffle furnace with a controllable atmosphere, nitrogen is introduced, the temperature is raised to 800°C in a flowing atmosphere, and heat treated for 4 hours. The atmosphere is switched to a mixture of ethanol vapor and nitrogen, the ratio of nitrogen to ethanol is 10, the heat treatment temperature is 800°C, and the treatment time is 4 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 800°C, and the heat treatment time is 4 hours. A second catalyst precursor is obtained.

[0090] (3) Prepare a 2.5% KH792 silane coupling agent solution, heat the silane coupling agent solution to 100° C., place the second catalyst precursor in the silane coupling agent solution for treatment, then take out the solid obtained after the treatment, wash it to neutrality, and dry it to obtain a third catalyst precursor.

[0091] (4) 100 g of hypophosphorous acid, 500 g of metasilicic acid and 500 g of sodium aluminate were added to water respectively, stirred evenly, and then 550 g of triethylamine was added and stirred until a uniform colloidal liquid was formed, 220 g of the third catalyst precursor was added to the colloidal liquid, and then the colloidal liquid was transferred to a hydrothermal reactor, heated to 200° C., and hydrothermally treated for 24 hours. After the treatment was completed, the catalyst was washed to neutrality and dried to obtain a fourth catalyst precursor.

[0092] (5) Prepare a 5% barium formate solution, heat the solution to 100° C., place the fourth catalyst precursor in the solution, treat for 2 hours, then take out the catalyst precursor, clean it and dry it. This treatment is carried out 5 times in total. After the treatment, calcine the catalyst at 800° C. for 4 hours. The catalyst for preparing aminocapronitrile by ammoniation of caprolactam is obtained.

[0093] Example 5

[0094] A method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, specifically comprising the following steps:

[0095] (1) A mixed solution of manganese nitrate and magnesium formate with a concentration of 6% (the ratio of manganese to magnesium in terms of atoms is 1:1) is prepared, and a carboxylic acid type cation exchange resin is immersed in the metal salt solution, heated to 50° C., and treated for 4 hours, and then the resin is taken out, cleaned, and dried. The ion exchange treatment is performed 3 times in total to obtain a first catalyst precursor.

[0096] (2) The first catalyst precursor is placed in a muffle furnace with a controllable atmosphere, argon is introduced, the temperature is raised to 750°C in a flowing atmosphere, and the heat treatment is performed for 6 hours. The atmosphere is switched to a mixture of water vapor and argon, the ratio of nitrogen to water is 10, the heat treatment temperature is 600°C, and the treatment time is 6 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 500°C, and the heat treatment time is 6 hours. The second catalyst precursor is obtained.

[0097] (3) Prepare a 1.5% KH750 silane coupling agent solution, heat the silane coupling agent solution to 50° C., place the second catalyst precursor in the silane coupling agent solution for treatment, then take out the solid obtained after the treatment, wash it to neutrality, and dry it to obtain a third catalyst precursor.

[0098] (4) 100g of ammonium phosphate, 100g of tetraethyl orthosilicate and 80g of γ-alumina are added to water respectively, stirred evenly, and then 260g of propylene diamine and 160g of propylene diamine are added, stirred until a uniform colloidal liquid is formed, 100g of the third catalyst precursor is added to the colloidal liquid, and then the colloidal liquid is transferred to a hydrothermal reactor, heated to 180°C, and hydrothermally treated for 60h. After the treatment is completed, the catalyst is washed to neutrality and dried. A fourth catalyst precursor is obtained.

[0099] (5) Prepare a 5% lithium nitrate solution, heat the solution to 50° C., place the fourth catalyst precursor in the solution, treat for 5 hours, then take out the catalyst precursor, clean it and dry it. This treatment is carried out twice. After the treatment, calcine the catalyst at 600° C. for 6 hours. The catalyst for preparing aminocapronitrile by ammoniation of caprolactam is obtained.

[0100] Example 6

[0101] A method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, specifically comprising the following steps:

[0102] (1) A mixed solution of cobalt acetate and nickel acetate with a concentration of 5% (the ratio of cobalt to nickel in terms of atoms is 1:1) is prepared, and a sulfonic acid type cation exchange resin is immersed in the metal salt solution, heated to 80° C., and treated for 8 hours, and then the resin is taken out, cleaned, and dried. The ion exchange treatment is performed 5 times in total to obtain a first catalyst precursor.

[0103] (2) The first catalyst precursor is placed in a muffle furnace with a controllable atmosphere, nitrogen is introduced, the temperature is raised to 450°C in a flowing atmosphere, and heat treated for 7 hours. The atmosphere is switched to a mixture of methanol vapor and nitrogen, the ratio of nitrogen to methanol is 4, the heat treatment temperature is 600°C, and the treatment time is 6 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 700°C, and the heat treatment time is 8 hours. The second catalyst precursor is obtained.

[0104] (3) Prepare a 2.0% KH740 silane coupling agent solution, heat the silane coupling agent solution to 80° C., place the second catalyst precursor in the silane coupling agent solution for treatment, then take out the solid obtained after the treatment, wash it to neutrality, and dry it to obtain a third catalyst precursor.

[0105] (4) 100 g of phosphoric acid, 200 g of silica sol and 100 g of pseudo-boehmite are added to water respectively, stirred evenly, and then 400 g of ethylamine and 240 g of propylene diamine are added and stirred until a uniform colloidal liquid is formed, 200 g of the third catalyst precursor is added to the colloidal liquid, and then the colloidal liquid is transferred to a hydrothermal reactor, heated to 175° C., and hydrothermally treated for 72 hours. After the treatment is completed, the catalyst is washed to neutrality and dried to obtain a fourth catalyst precursor.

[0106] (5) Prepare a 2.0% beryllium acetate solution, heat the solution to 60° C., place the fourth catalyst precursor in the solution, treat for 4 hours, then take out the catalyst precursor, clean it and dry it. This treatment is carried out twice. After the treatment, calcine the catalyst at 750° C. for 6 hours. The catalyst for preparing aminocapronitrile by ammoniation of caprolactam is obtained.

[0107] Comparative Example 1

[0108] A method for preparing a catalyst for amination reaction of caprolactam catalyst, specifically:

[0109] (1) A mixed solution of manganese nitrate and magnesium formate with a concentration of 6% (the ratio of manganese to magnesium in terms of atoms is 1:1) is prepared, and a carboxylic acid type cation exchange resin is immersed in the metal salt solution, heated to 50° C., and treated for 4 hours. The resin is then taken out, cleaned, and dried. The ion exchange treatment is performed 3 times in total.

[0110] (2) The catalyst precursor obtained in step (1) is placed in a muffle furnace with a controllable atmosphere, argon is introduced, the temperature is raised to 750°C in a flowing atmosphere, and heat treated for 6 hours. The atmosphere is switched to a mixture of water vapor and argon, the ratio of nitrogen to water is 10, the heat treatment temperature is 600°C, and the treatment time is 6 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 500°C, and the heat treatment time is 6 hours to obtain a catalyst for the amination reaction of caprolactam.

[0111] Comparative Example 2

[0112] A method for preparing a catalyst for amination reaction of caprolactam catalyst, specifically:

[0113] (1) A mixed solution of manganese nitrate and magnesium formate with a concentration of 6% (the ratio of manganese to magnesium in terms of atoms is 1:1) is prepared, and a carboxylic acid type cation exchange resin is immersed in the metal salt solution, heated to 50° C., and treated for 4 hours. The resin is then taken out, cleaned, and dried. The ion exchange treatment is performed 3 times in total.

[0114] (2) The catalyst precursor obtained in step (1) is placed in a muffle furnace with a controllable atmosphere, argon is introduced, the temperature is raised to 750°C in a flowing atmosphere, and the heat treatment is performed for 6 hours. The atmosphere is switched to a mixture of water vapor and argon, the ratio of nitrogen to water is 10, the heat treatment temperature is 600°C, and the treatment time is 6 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 500°C, and the heat treatment time is 6 hours.

[0115] (3) 100 g of ammonium phosphate, 100 g of tetraethyl orthosilicate and 80 g of γ-alumina were added to water respectively, stirred evenly, and then 260 g of propylene diamine and 160 g of propylene diamine were added, stirred until a uniform colloidal liquid was formed, 100 g of the catalyst precursor prepared in step (2) was added to the colloidal liquid, and then the colloidal liquid was transferred to a hydrothermal reactor, heated to 180° C., and hydrothermally treated for 60 h. After the treatment was completed, the catalyst was washed to neutrality and dried.

[0116] (5) Prepare a 5% lithium nitrate solution, heat the solution to 50°C, place the catalyst precursor obtained in step (3) in the solution, treat for 5 hours, then take out the catalyst, clean it and dry it. This treatment is carried out twice. After the treatment, calcine the catalyst at 600°C for 6 hours. Obtain a catalyst for the amination reaction of caprolactam.

[0117] Comparative Example 3

[0118] A method for preparing a catalyst for amination reaction of caprolactam catalyst, specifically:

[0119] (1) A mixed solution of manganese nitrate and magnesium formate with a concentration of 6% (the ratio of manganese to magnesium in terms of atoms is 1:1) is prepared, and a carboxylic acid type cation exchange resin is immersed in the metal salt solution, heated to 50° C., and treated for 4 hours. The resin is then taken out, cleaned, and dried. The ion exchange treatment is performed 3 times in total.

[0120] (2) The catalyst precursor obtained in step (1) is placed in a muffle furnace with a controllable atmosphere, argon is introduced, the temperature is raised to 750°C in a flowing atmosphere, and the heat treatment is performed for 6 hours. The atmosphere is switched to a mixture of water vapor and argon, the ratio of nitrogen to water is 10, the heat treatment temperature is 600°C, and the treatment time is 6 hours. The atmosphere is then switched back to nitrogen, the heat treatment temperature is 500°C, and the heat treatment time is 6 hours.

[0121] (3) Prepare a 1.5% KH750 silane coupling agent solution, heat the silane coupling agent solution to 50° C., place the catalyst precursor obtained in step (2) in the silane coupling agent solution for treatment, then take out the solid obtained after the treatment, wash it to neutrality, and dry it.

[0122] (4) 100g of ammonium phosphate, 100g of tetraethyl orthosilicate and 80g of γ-alumina are added to water respectively, stirred evenly, and then 260g of propylene diamine and 160g of propylene diamine are added, stirred until a uniform colloidal liquid is formed, 100g of the catalyst precursor obtained in step (3) is added to the colloidal liquid, and then the colloidal liquid is transferred to a hydrothermal reactor, heated to 180°C, and hydrothermally treated for 60h. After the treatment is completed, the catalyst is washed to neutrality and dried. After the treatment is completed, the catalyst is calcined at 600°C for 6h. A catalyst for the amination reaction of caprolactam is obtained.

[0123] Comparative Example 4

[0124] A method for preparing a catalyst for amination reaction of caprolactam catalyst, specifically:

[0125] (1) A mixed solution of manganese nitrate and magnesium formate with a concentration of 6% (the ratio of manganese to magnesium in terms of atoms is 1:1) is prepared and slowly evaporated at 80°C until a mixed metal salt is formed. The mixed metal salt is placed in a muffle furnace with a controlled atmosphere, argon gas is introduced, the temperature is raised to 750°C in a flowing atmosphere, and heat treated for 6 hours to obtain a metal oxide.

[0126] (2) preparing a 1.5% KH750 silane coupling agent solution, heating the silane coupling agent solution to 50° C., placing the metal oxide obtained in step (1) in the silane coupling agent solution for treatment, then taking out the solid obtained after the treatment, washing it to neutrality, and drying it.

[0127] (3) 100 g of ammonium phosphate, 100 g of tetraethyl orthosilicate and 80 g of γ-alumina were added to water respectively, stirred evenly, and then 260 g of propylene diamine and 160 g of propylene diamine were added, stirred until a uniform colloidal liquid was formed, 100 g of the catalyst precursor prepared in step (2) was added to the colloidal liquid, and then the colloidal liquid was transferred to a hydrothermal reactor, heated to 180° C., and hydrothermally treated for 60 h. After the treatment was completed, the catalyst was washed to neutrality and dried.

[0128] (4) Prepare a 5% lithium nitrate solution, heat the solution to 50°C, place the catalyst precursor obtained in step (3) in the solution, treat for 5 hours, then take out the catalyst precursor, clean it and dry it. This treatment is carried out twice. After the treatment, calcine the catalyst at 600°C for 6 hours. Obtain a catalyst for the amination reaction of caprolactam.

[0129] Comparative Example 5

[0130] A method for preparing a catalyst for amination reaction of caprolactam catalyst, specifically:

[0131] A mixed solution of manganese nitrate and magnesium formate with a concentration of 15% (the ratio of manganese to magnesium in terms of atoms is 1:1) is prepared and heated to 50°C. A 10% phosphoric acid solution is gradually added to the magnesium nitrate solution until no new precipitation is generated. The generated solid is washed with water until it is neutral and dried. The catalyst is calcined at 550°C for 6 hours. A catalyst for preparing aminocapronitrile from caprolactam is obtained.

[0132] Test Case

[0133] The present invention tests the catalysts prepared in Examples 1-6 for synthesizing aminocapronitrile from caprolactam, and the finished catalysts prepared in Comparative Examples 1-5 for catalyzing the amination of caprolactam to prepare aminocapronitrile. The specific control conditions and test results are as follows.

[0134] Implementation of test case 1

[0135] The catalyst obtained in Example 1 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 400°C and the reaction space velocity was 8.0 h -1 The single-pass conversion rate of caprolactam was 84.93%, the yield of aminocapronitrile was 97.63%, and the catalyst life was 6280h.

[0136] Implementation of Test Example 2

[0137] The catalyst obtained in Example 2 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 300°C and the reaction space velocity was 2.0 h -1 The single-pass conversion rate of caprolactam was 77.74%, the yield of aminocapronitrile was 97.76%, and the catalyst life was 5400h.

[0138] Implementation of Test Case 3

[0139] The catalyst obtained in Example 3 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 360°C and the reaction space velocity was 6h -1 The single-pass conversion rate of caprolactam was 84.67%, the yield of aminocapronitrile was 97.23%, and the catalyst life was 5520h.

[0140] Implementation of Test Case 4

[0141] The catalyst obtained in Example 4 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 380°C and the reaction space velocity was 6.5h -1 The single-pass conversion rate of caprolactam was 82.93%, the yield of aminocapronitrile was 97.02%, and the catalyst life was 5240h.

[0142] Implementation of Test Case 5

[0143] The catalyst obtained in Example 5 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 320°C and the reaction space velocity was 3.0 h -1 The single-pass conversion rate of caprolactam was 79.96%, the yield of aminocapronitrile was 97.22%, and the catalyst life was 6540h.

[0144] Implementation of Test Case 6

[0145] The catalyst obtained in Example 6 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 380°C and the reaction space velocity was 7.5h -1The single-pass conversion rate of caprolactam was 86.98%, the yield of aminocapronitrile was 97.42%, and the catalyst life was 6400h.

[0146] Comparative test example 1

[0147] The catalyst obtained in Comparative Example 1 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 360°C, the reaction space velocity was 1.0 h -1 The one-way conversion rate of caprolactam was 5.07%, and the yield of aminocapronitrile was 24.86%. The catalyst life of the present invention is evaluated by the one-way conversion rate of the raw material. In the comparative test example, the one-way conversion rate of caprolactam is relatively low, so the catalyst life does not need to be routinely tested.

[0148] Comparative test example 2

[0149] The catalyst obtained in Comparative Example 2 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 360°C, the reaction space velocity was 2.0 h -1 The single-pass conversion rate of caprolactam was 58.73%, the yield of aminocapronitrile was 92.97%, and the catalyst life was 3150h.

[0150] Comparative test example 3

[0151] The catalyst obtained in Comparative Example 3 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 360°C and the reaction space velocity was 4.0 h -1 The single-pass conversion rate of caprolactam was 82.84%, the yield of aminocapronitrile was 93.98%, and the catalyst life was 6200h.

[0152] Comparative test example 4

[0153] The catalyst obtained in Comparative Example 4 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 360°C, the reaction space velocity was 4.0 h -1 The single-pass conversion rate of caprolactam was 61.22%, the yield of aminocapronitrile was 96.87%, and the catalyst life was 2400h.

[0154] Comparative test example 5

[0155] The catalyst obtained in Comparative Example 5 was placed in a fixed bed reaction evaluation device for evaluation; the reaction temperature was 360°C, the reaction space velocity was 4.0 h -1 The single-pass conversion rate of caprolactam was 68.02%, the yield of aminocapronitrile was 95.67%, and the catalyst life was 2040h.

[0156] It should be noted that the above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions; the dimensional data of this embodiment does not limit the technical solution, but only shows one of the specific working conditions. For ordinary technicians in the technical field to which the present invention belongs, several simple improvements and modifications can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam, characterized in that: The following steps are involved: (1) performing a first step of ion exchange in a first metal salt solution using an ion exchange resin to obtain a first catalyst precursor; (2) carbonizing the first catalyst precursor and activating the carbonized catalyst precursor to obtain a second catalyst precursor; (3) treating the second catalyst precursor with a silane coupling agent to obtain a third catalyst precursor; (4) The third catalyst precursor is subjected to hydrothermal treatment in a gel solution containing a phosphorus source, a silicon source, an aluminum source and an organic amine to obtain a fourth catalyst precursor; (5) The fourth catalyst precursor is subjected to a second step of ion exchange in a second metal salt solution to obtain the catalyst for preparing aminocapronitrile by amination of caprolactam.

2. The method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 1, characterized in that: The first step of ion exchange comprises: contacting an ion exchange resin with a first metal salt solution; Preferably, the ion exchange resin is an acidic cation exchange resin; Preferably, the acidic cation exchange resin includes one or both of a carboxylic acid cation exchange resin and a sulfonic acid cation exchange resin; And / or, the temperature of the first step ion exchange is 20-100° C. and the time is 2-10 h; And / or, the number of times of the first step ion exchange is 1 to 5 times.

3. The method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 1, characterized in that: The first metal salt solution is prepared by dissolving a first metal salt in water; Preferably, the cation of the first metal salt comprises Ni 2+ 、Co 2+ 、Ce 3+ , Fe 3+ Mg 2+ ,La + , Mn 4+ 、Zn 2+ At least one of; Preferably, the anion of the first metal salt includes at least one of nitrate, formate, acetate and benzoate; Preferably, the mass concentration of the first metal salt solution is 1-10%.

4. The method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 1, characterized in that: The carbonization process in step (2) comprises: heat treating the first catalyst precursor in a flowing inert atmosphere; Preferably, the temperature of the carbonization process is 300-800° C., and the processing time is 4-12 hours.

5. The method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 1, characterized in that: The activation process in step (2) comprises: heat treating the carbonized first catalyst precursor in an atmosphere containing a reaction gas and an inert gas; Preferably, the reaction gas includes at least one of water vapor, ethanol vapor, and methanol vapor; Preferably, the molar ratio of the inert gas to the reactive gas in the atmosphere is 1 to 10; Preferably, the temperature of the activation process is 300-800°C and the treatment time is 4-12h; Preferably, the activation process further comprises switching to an inert atmosphere for purging after the activation is completed; Preferably, the temperature of the purging process is 300-500° C., and the processing time is 2-4 hours.

6. The method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 1, characterized in that: The silane coupling agent treatment in step (3) comprises: contacting the second catalyst precursor with a silane coupling agent solution; Preferably, the silane coupling agent includes at least one of a vinyl silane coupling agent, a chloroalkyl silane coupling agent, an aminoalkyl silane coupling agent, an epoxyalkyl silane coupling agent, a methacryloxyalkyl silane coupling agent, a sulfur-containing hydrocarbon silane coupling agent, a pseudohalogen silane coupling agent and a quaternary ammonium hydrocarbon silane coupling agent; Preferably, the mass concentration of the silane coupling agent solution is 0.5-2.5%; Preferably, the temperature of the silane coupling agent treatment is 30-100°C.

7. The method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 1, characterized in that: In the step (4), the phosphorus source includes at least one of phosphoric acid, pyrophosphoric acid, hypophosphorous acid, and ammonium phosphate; And / or, the silicon source includes at least one of silica sol, tetraethyl orthosilicate, fumed silicon oxide, silicic acid, and metasilicic acid; and / or, the aluminum source includes at least one of 20% aluminum sol, pseudo-boehmite, sodium aluminate, and γ-alumina; and / or, the organic amine includes at least one of diethylamine, ethylenediamine, ethylamine, n-propylamine, propylenediamine, and triethylamine; And / or, the mass ratio of the phosphorus source, silicon source and aluminum source is 1:(0.5-5):(0.2-2); and / or, the mass ratio of the organic amine to the total amount of the phosphorus source, the silicon source and the aluminum source is 1:(0.5-5); And / or, the temperature of the hydrothermal treatment in step (4) is 120 to 200° C., and the treatment time is 24 to 72 hours; And / or, the mass ratio of the third catalyst precursor to the sum of the masses of the silicon source, the aluminum source and the phosphorus source is 1:(1-5).

8. The method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 1, characterized in that: In the step (5), the second ion exchange comprises: contacting the fourth catalyst precursor with a second metal salt solution; Preferably, the temperature of the second step ion exchange is 30-100°C and the time is 2-10h; And preferably, the number of ion exchange in the second step is 1 to 5 times; And / or, the second metal salt solution is prepared by dissolving a second metal salt in water; Preferably, the cation of the second metal salt is an alkali metal and / or an alkaline earth metal; Further preferably, the cation of the second metal salt comprises Li + 、Na + , K + 、Be 2+ Mg 2+ , Ca 2+ , Ba 2+ At least one of; Preferably, the anion of the second metal salt includes at least one of nitrate, formate, acetate, and benzoate; Preferably, the mass concentration of the second metal salt is 0.5-5%; Preferably, the step (5) further comprises washing and calcining the catalyst precursor after the second step of ion exchange; Preferably, the calcination temperature is 400-800° C., and the calcination time is 4-12 hours.

9. A catalyst for preparing aminocapronitrile by ammoniation of caprolactam, characterized in that The catalyst is prepared by the method for preparing a catalyst for preparing aminocapronitrile by ammoniation of caprolactam as described in any one of claims 1 to 8.

10. Use of the catalyst for preparing aminocapronitrile by ammoniation of caprolactam according to claim 9 in preparing aminocapronitrile from caprolactam.

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