Process for the preparation of hexamethylenediamine by amination reaction

Abstract

This invention relates to the field of hexamethylenediamine production technology and discloses a method for preparing hexamethylenediamine by ammoniation reaction. The method includes the following steps: (a) under hydrogen-containing conditions and in the presence of an ammoniation catalyst, hexanediol and ammonia undergo an ammoniation reaction to obtain an ammoniation product; (b) unreacted hydrogen and ammonia in the ammoniation product are pre-separated to obtain a pre-separated product and a material containing hydrogen and ammonia, and the material containing hydrogen and ammonia is returned to step (a); (c) the pre-separated product is separated to obtain a material containing cyclohexylimine, hexamethylenediamine, a material containing aminohexanol, and a material containing C12 amine; wherein part or all of the mixture of the material containing cyclohexylimine and / or the material containing aminohexanol is returned to step (a); (d) the material containing C12 amine is subjected to ammonolysis. The technical solution of this invention achieves an increase in the yield of hexamethylenediamine prepared by the ammoniation of hexanediamine through ammonolysis.

Description

Technical Field

[0001] This invention relates to the field of hexamethylenediamine production technology, specifically a method for preparing hexamethylenediamine by an amination reaction. Background Technology

[0002] Hexamethylenediamine (HMD) has two highly reactive amino groups, making it suitable for use as an intermediate monomer in the synthesis of numerous chemicals and giving it significant industrial value. For example, HMD is used in the condensation polymerization of hexamethylenediamine with adipic acid or sebacic acid to prepare nylon 66 and nylon 610, which are then further used to synthesize other important chemical materials such as nylon resins, nylon fibers, polyamide resins, and inks.

[0003] Currently, adiponitrile is the main method for producing hexamethylenediamine in China, but adiponitrile technology has high barriers to entry and investment. Limited by the supply of adiponitrile raw materials, over 90% of global hexamethylenediamine production capacity is concentrated in Europe and the United States, resulting in extremely high industry concentration. Faced with an increasingly competitive international environment, my country's hexamethylenediamine production capacity is insufficient to meet its growing demand, making the large-scale industrial production of hexamethylenediamine particularly urgent.

[0004] In 2006, CN106810454A developed a catalyst for the amination of alcohols. The main active component is nickel and / or cobalt, and the auxiliary agents are one or more metals or oxides such as Fe, Cu, Ru, Re, K, Zn, and B. The support is one or two of SiO2 or Al2O3. Hexanediol is ammoniated and dehydrated under hydrogen-containing conditions to produce hexanediamine, but the yield is low. Besides hexanediamine, the products of hexanediol ammoniation also include cyclohexylimine, aminohexanol, and a certain amount of amine dimers (C12 amines, such as bis(hexamethylene)triamine and other amines with 12 carbon atoms). This method has the advantages of simple process, non-toxic materials, environmentally friendly emissions, and high inherent safety, but the yield is low.

[0005] In summary, existing technologies suffer from limited raw material sources, and the hydroammoniation of hexanediol to produce hexanediamine has a low yield. Furthermore, the C12 amine component in the product can only be discharged as waste liquid, resulting in resource waste. Summary of the Invention

[0006] The purpose of this invention is to overcome the aforementioned technical problems in the prior art and to provide a method for preparing hexamethylenediamine by amination reaction.

[0007] To achieve the above objectives, the present invention provides a method for preparing hexamethylenediamine by amination reaction, the method comprising the following steps:

[0008] (a) Hexanediol and ammonia are subjected to an ammoniation reaction under hydrogen-exposed conditions and in the presence of an ammoniation reaction catalyst to obtain the ammoniation reaction product;

[0009] (b) The unreacted hydrogen and ammonia in the ammoniation reaction product are pre-separated to obtain a pre-separated product and a material containing hydrogen and ammonia, and the material containing hydrogen and ammonia is returned to step (a).

[0010] (c) The pre-separation product is separated to obtain a material containing cyclohexylimine, hexamethylenediamine, aminohexanol, and C12 amine; wherein part or all of the mixture of the material containing cyclohexylimine and / or the material containing aminohexanol is returned to step (a).

[0011] (d) Ammonolysis of materials containing C12 amines.

[0012] The technical solution of the present invention has the following advantages: the technical solution of the present invention improves the yield of hexanediamine prepared by ammonolysis of hexanediol; the technical solution of the present invention overcomes the dependence on adiponitrile raw materials. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] In this invention, hexamethylenediamine is 1,6-hexamethylenediamine, hexanediol is 1,6-hexanediol, and aminohexanol is 6-amino-1-hexanol.

[0015] The inventors of this invention have discovered that returning cyclohexylimine and / or aminohexanol from the ammoniation reaction products to the ammoniation reaction, while simultaneously ammonolyzing the C12 amine-containing material from the ammoniation products, can improve the yield of hexamethylenediamine. Therefore, this invention provides a method for preparing hexamethylenediamine by ammoniation reaction, the method comprising the following steps:

[0016] (a) Hexanediol and ammonia are subjected to an ammoniation reaction under hydrogen-exposed conditions and in the presence of an ammoniation reaction catalyst to obtain the ammoniation reaction product;

[0017] (b) The unreacted hydrogen and ammonia in the ammoniation reaction product are pre-separated to obtain a pre-separated product and a material containing hydrogen and ammonia, and the material containing hydrogen and ammonia is returned to step (a).

[0018] (c) The pre-separation product is separated to obtain a material containing cyclohexylimine, hexamethylenediamine, aminohexanol, and C12 amine; wherein part or all of the mixture of the material containing cyclohexylimine and / or the material containing aminohexanol is returned to step (a).

[0019] (d) Ammonolysis of materials containing C12 amines.

[0020] In this invention, the C12 amine in the material containing C12 amine is an amine compound with 12 carbon atoms, such as bis(hexamethylene)triamine.

[0021] According to the present invention, preferably, in step (a), the molar ratio of ammonia to hexanediol is 15-42:1, more preferably 25-38:1, and the molar ratio of hydrogen to hexanediol provided by the hydrogenation conditions is 0.09-8:1, more preferably 0.6-3.5:1. Wherein, the molar ratio of ammonia, hydrogen, and hexanediol refers to the molar ratio of the mixture at the inlet of the ammoniation reactor.

[0022] According to the present invention, preferably, the temperature of the ammoniation reaction is 115-205°C, more preferably 130-195°C; the pressure of the ammoniation reaction is 6.5-17 MPaG, more preferably 9-15 MPaG; and the liquid hourly space velocity of fresh hexanediol is 0.08-6 h⁻¹. -1 Preferably, it is 0.1-3.8h. -1 .

[0023] In step (a), the ammoniation catalyst is not specifically limited and can be any publicly disclosed catalyst suitable for the ammoniation of hexanediol, such as those mentioned in publications like CN114433113A, CN114433087A, and CN114433121A. Preferably, the ammoniation catalyst comprises a support and an active component and an auxiliary agent supported on the support, characterized in that the active component is cobalt and / or nickel; and the auxiliary agent is a combination of at least one group VIB metal, at least one group IB metal, and at least one group IIB metal.

[0024] According to the ammoniation catalyst of the present invention, preferably, the support comprises an alumina support, a dopant element, and other supports, wherein the other supports are selected from silica and / or molecular sieves; the ammonia adsorption capacity of the support is 0.2-0.6 mmol / g; the percentage of pore volume in the support with a pore size in the range of 7-27 nm is greater than 65%, preferably 70-90%; the percentage of pore volume with a pore size less than 7 nm is 0-8%, preferably 0-5%; and the specific surface area of ​​the support is 120-210 m² / g. 2 / g; the pore volume of the carrier is 0.45-1.1ml / g.

[0025] According to the ammoniation catalyst of the present invention, preferably, the content of alumina support in the support accounts for more than 70% by weight of the total amount of alumina support and other supports, preferably 80-97% by weight.

[0026] According to the ammoniation catalyst of the present invention, preferably, the content of the dopant element is 0.05-5% by weight of the content of the support, and more preferably 0.08-3% by weight.

[0027] According to the ammoniation catalyst of the present invention, preferably, the alumina precursor of the support is doped with at least one of borate ions, fluoride ions, phosphate ions, sulfate ions, and selenate ions. The doping element is preferably selected from at least one of boron, fluorine, phosphorus, sulfur, and selenium. The non-metallic element is doped during the preparation of the precursor of the support, so that the doping element is mainly present in the bulk phase of the support, rather than attached to the surface.

[0028] According to the ammoniation catalyst of the present invention, preferably, the content of the active component is 10-46g, more preferably 18-38g, relative to 100g of the support.

[0029] According to the ammoniation catalyst of the present invention, preferably, the content of the auxiliary agent is 0.1-10g, more preferably 0.5-6g, relative to 100g of the carrier.

[0030] According to the ammoniation catalyst of the present invention, preferably, the weight ratio of Group VIB metal, Group IB metal and Group IIB metal in the promoter is 0.1-10:0.1-10:1, more preferably 0.2-8:0.2-8:1, and even more preferably 0.5-4:0.5-6:1. Preferably, the Group VIB metal is selected from molybdenum and / or tungsten. Preferably, the Group IB metal is selected from at least one of copper, silver and gold. Preferably, the Group IIB metal is selected from zinc.

[0031] According to the present invention, preferably, in step (b), the pre-separation conditions result in a hydrogen recovery rate of over 99% and an ammonia recovery rate of over 98%. The pre-separation conditions can be any method capable of separating hydrogen and ammonia from the ammoniation reaction products; however, considering both hydrogen and ammonia recovery rates and energy consumption, the pre-separation method is preferably selected from at least one of flash evaporation, distillation, and membrane separation. The pre-separation method can include at least two stages of flash evaporation, with the flash pressure decreasing in a gradient of 1-6 MPa to 0.1-4 MPaG. The pre-separation method can also be a combination of at least one stage of flash evaporation and distillation, with the flash pressure decreasing in a gradient of 1-6 MPa to 0.1-4 MPaG, followed by distillation of the liquid phase after flash evaporation. The distillation operating conditions include: a theoretical plate number of 6-20 and a pressure of 0-3 MPaG.

[0032] In this invention, it is understood that since ammonia is consumed during the ammoniation reaction and a small amount of hydrogen and ammonia are lost during the hydrogen and ammonia recovery process, it is necessary to replenish fresh ammonia and hydrogen during the ammoniation reaction to maintain the molar ratio of hexanediol (including freshly replenished hexanediol and hexanediol in the recycled material), ammonia and hydrogen in the mixture at the feed inlet of the ammoniation reactor.

[0033] According to the present invention, preferably, the pre-separated products are separated by at least one of distillation, membrane separation and pressure swing adsorption.

[0034] In a preferred embodiment of the present invention, the method for separating the pre-separated product includes: based on different boiling points, hexamethylenediamine is used as the key component for segmentation and separation; a first separation is performed sequentially to obtain a stream containing cyclohexylimine and the remaining material; then the remaining material undergoes a second separation to obtain a hexamethylenediamine product and a material containing aminohexanol and C12 amine; then the material containing aminohexanol and C12 amine undergoes a third separation to obtain a material containing aminohexanol and a material containing C12 amine; the material containing C12 amine is fed into an ammonolysis reactor for ammonolysis reaction, and the heavy components are extracted. The conditions for the first separation include: a theoretical plate number of 10-35 and a pressure of -0.1 MPaG to 0.9 MPaG; the conditions for the second separation include: a theoretical plate number of 10-40 and a pressure of -0.1 MPaG to 0.8 MPaG; and the conditions for the third separation include: a theoretical plate number of 30-100 and a pressure of -0.1 MPaG to 0.7 MPaG.

[0035] In this invention, a small amount of heavy components are generated during ammonolysis (heavy components mainly include amine compounds with more than 12 carbon atoms, such as amines with 18 carbon atoms). The ammonolysis product can be directly returned to step (b). After pre-separation in step (b) and separation in step (c), the heavy components are collected. For example, the second separation yields a material containing aminohexanol, C12 amine, and heavy components. The material containing aminohexanol, C12 amine, and heavy components is then subjected to a third separation to obtain a material containing aminohexanol, a material containing C12 amine, and heavy components. The heavy components are directly discharged. Alternatively, the heavy components can be removed before the ammonolysis product is returned to step (b). For example, the ammonolysis product can be separated by a coarse separation tower, and the top material of the coarse separation tower can be returned to step (b), while the bottom material (heavy components) is directly discharged.

[0036] According to the present invention, preferably, the weight ratio of the mixture containing cyclohexylimine and / or aminohexanol returned to step (a) to fresh hexanediol is 0.02-15:1, more preferably 0.04-10:1. More preferably, the total content of cyclohexylimine and aminohexanol in the mixture returned to step (a) is 20-90% by weight. It should be noted that, at the beginning of the reaction, the amount of cyclohexylimine and aminohexanol generated by the ammoniation reaction is small and cannot meet the above-defined mass ratio of the mixture to hexanediol; therefore, in the initial stage of the reaction, all the stream containing cyclohexylimine and / or the stream containing aminohexanol is returned to the ammoniation reaction. However, in the stable operation stage of the reaction, the amount of cyclohexylimine and aminohexanol generated by the ammoniation reaction is large, and at this time, it is sufficient to ensure that the returned mixture meets the above-defined mass ratio. The weight ratio of the mixture to fresh hexanediol given in the embodiments of this application is the mass ratio during the stable operation phase of the reaction.

[0037] According to the present invention, preferably, step (d) includes: contacting the material containing C12 amine and ammonia with an ammonolysis catalyst under hydrogen-containing conditions to obtain ammonolysis reaction products, the ammonolysis reaction products being returned to step (b) with or without separation.

[0038] According to the present invention, preferably, the conditions for the ammonolysis reaction include: a reaction temperature of 135-255°C, more preferably 155-250°C; a reaction pressure of 9.5-24 MPaG, more preferably 10.5-22 MPaG; and a liquid hourly space velocity (LHSV) of 0.05-8 h⁻¹ for the C12 amine-containing material. -1 Preferably 0.08-4h -1 The mass ratio of hydrogen provided under hydrogen conditions to C12 amine in the material containing C12 amine is 0.01-0.18:1, preferably 0.02-0.13:1; the mass ratio of ammonia to C12 amine in the material containing C12 amine is 3.6-12.5:1, preferably 6.2-9.8:1.

[0039] According to the present invention, preferably, in step (d), the contact between the C12 amine-containing material and ammonia with the ammonolysis catalyst is carried out in a solvent environment, the solvent including at least one of tetrahydrofuran, 1,4-dioxane, n-hexane, cyclohexane and tert-butanol.

[0040] According to the present invention, preferably, the weight ratio of the solvent to the C12 amine-containing material is 0.1-10:1.

[0041] According to the present invention, preferably, the mixture of the cyclohexylimine-containing material and / or the aminohexanol-containing material returned to step (a) may also contain a solvent, the solvent content being 0-70% by weight (e.g., 0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, and any range of the above points).

[0042] In this invention, the ammonolysis catalyst can be prepared by the following method:

[0043] (1) Preparation of carrier: A mixture of boehmite, silica sol and calcium nitrate is contacted with an aqueous solution containing nitric acid and phosphoric acid, and then kneaded, dried and calcined in sequence;

[0044] (2) The carrier is immersed in an aqueous solution containing nickel sulfate, lanthanum acetate and indium nitrate, dried at 100-140℃ for 2-6 hours, and then calcined at 350-450℃ for 2-6 hours.

[0045] According to the preparation method of the ammonolysis catalyst of this invention, preferably, in step (1), the amount of silica sol is 0.6-0.8g, the amount of calcium nitrate is 0.1-0.4g, and the amount of aqueous solution containing nitric acid and phosphoric acid is 0.2-0.5g, relative to each gram of boehmite.

[0046] According to the preparation method of the ammonolysis catalyst of this invention, preferably, in step (1), the aqueous solution containing nitric acid and phosphoric acid has a nitric acid content of 10-25% by weight and a phosphoric acid content of 5-15% by weight.

[0047] According to the preparation method of the ammonolysis catalyst of this invention, preferably, in step (1), the drying temperature is 100-140℃ and the drying time is 1-6h.

[0048] According to the preparation method of the ammonolysis catalyst of this invention, preferably, in step (2), the amount of nickel sulfate is 0.6-0.85g, the amount of lanthanum acetate is 0.06-0.08g, and the amount of indium nitrate is 0.055-0.065g relative to each gram of support.

[0049] According to the preparation method of the ammonolysis catalyst of this invention, preferably, in step (2), the concentration of nickel sulfate in the aqueous solution containing nickel sulfate, lanthanum acetate and indium nitrate is 20-25% by weight, the concentration of lanthanum acetate is 1.5-2.5% by weight, and the concentration of indium nitrate is 1.5-2.5% by weight. The impregnation method is preferably the equal volume impregnation method, and the impregnation can be carried out in multiple times.

[0050] The present invention will be described in detail below through embodiments. In the following embodiments,

[0051] The ammoniation reaction catalyst of the present invention is the A-2 catalyst prepared according to the method of Example 2 in CN114433113A.

[0052] The composition of the product was analyzed by gas chromatography.

[0053] The yield of hexamethylenediamine = molar amount of hexamethylenediamine product ÷ molar amount of fresh hexanediol × 100%.

[0054] Preparation Example 1

[0055] Preparation of ammonolysis catalysts via a multi-step impregnation method:

[0056] (1) Weigh the pseudoboehmite (produced by the aluminum sulfate method, with a specific surface area of ​​310 m²). 2 The mixture consisted of 94.2 g of pseudoboehmite (1.19 ml / g pore volume), 72.5 g of silica sol (JN-40), and 25.26 g of calcium nitrate tetrahydrate. The pseudoboehmite was placed in a kneader. The weighed silica sol and calcium nitrate tetrahydrate were added to 24.77 g of water to prepare a solution, which was then added to the kneader and thoroughly stirred with the pseudoboehmite. An aqueous solution consisting of 16.51 g of water, 4.71 g of nitric acid, and 2.83 g of phosphoric acid was then added and thoroughly stirred. The mixture was then kneaded and extruded into a clover shape, dried at 120°C for 4 hours, and then calcined in a muffle furnace at 900°C for 6 hours. After cooling, the carrier was obtained.

[0057] (2) Add 100.77g of nickel sulfate hexahydrate (industrial grade, purity 98%), 5.69g of lanthanum acetate monohydrate and 5.96g of indium nitrate pentahydrate to 134.78mL of water to prepare an aqueous solution. Load the solution onto the 73.25g carrier obtained in step (1) using the equal volume impregnation method in two separate steps. After each impregnation, dry at 120℃ for 4 hours. After the two impregnations are completed, calcine at 390℃ for 4 hours.

[0058] Example 1

[0059] (a) Ammonia, hydrogen, and hexanediol are introduced into an ammoniation reactor packed with a catalyst, wherein the molar ratio of ammonia to hexanediol is 35:1, the molar ratio of hydrogen to hexanediol is 2:1, the ammoniation reaction temperature is 150°C, the reaction pressure is 12 MPaG, and the liquid hourly space velocity of hexanediol is 1 h⁻¹. -1 .

[0060] (b) The products of the ammoniation reaction are sequentially passed through three flash tanks for three-stage vacuum flash evaporation to recover hydrogen. The pressures of the first to the third flash tanks are set to 9 MPaG, 5 MPaG, and 2 MPaG, respectively. The vapor phases at the top of each of the three flash tanks are cooled to 45°C and then further separated into liquid and gas phases. The resulting liquid phases are returned to each stage of the vacuum flash tank, while the vapor phases are pressurized to the ammoniation reaction pressure and returned to the ammoniation reactor. The bottom liquid phase of the third vacuum flash tank enters the deammoniation distillation column from the top. The column has 11 trays and an operating pressure of 2 MPaG at the top. For energy conservation and cost reduction, no condenser is installed at the top of the deammoniation distillation column. The top material of the deammoniation distillation column is sent back to the inlet of the ammoniation reactor, while the bottom material is subjected to further purification.

[0061] (c) In step (b), the bottom feed of the deammoniation distillation column is separated based on its boiling point, with hexamethylenediamine as the key component. The first separation yields a stream containing cyclohexylimine and the remaining material. The remaining material then undergoes a second separation to obtain the hexamethylenediamine product and a stream containing aminohexanol, C12 amine, and heavy components. The stream containing aminohexanol, C12 amine, and heavy components then undergoes a third separation to obtain the stream containing aminohexanol, the stream containing C12 amine, and the heavy components. The heavy components are directly discharged, while the stream containing C12 amine is sent to the ammonolysis reactor. The mixture of the aminohexanol-containing stream and the cyclohexylimine-containing stream is returned to step (a), with a weight ratio of 1.9:1 to fresh hexamethylenediamine. The conditions for the first separation are: 18 theoretical plates and -0.07 MPaG pressure; the conditions for the second separation are: 19 theoretical plates and -0.08 MPaG pressure; the conditions for the third separation are: 55 theoretical plates and -0.09 MPaG pressure.

[0062] (d) The ammonolysis reactor was filled with the ammonolysis catalyst prepared in Preparation Example 1. The C12 amine-containing material, ammonia, and hydrogen were fed into the ammonolysis reactor for ammonolysis. The reaction conditions included a mass ratio of ammonia to C12 amine in the material of 7.6:1, a molar ratio of hydrogen to C12 amine in the material of 0.04:1, an ammonolysis reaction temperature of 170°C, an ammonolysis reaction pressure of 12 MPaG, and a liquid hourly space velocity (LHSV) of 0.5 h⁻¹ for the C12 amine-containing material. -1 The products of ammonolysis are returned to step (b).

[0063] The mass composition of each stream during stable reaction operation is shown in Table 1. The molar yield of hexamethylenediamine was 90.69%.

[0064] Table 1

[0065]

[0066] Note: 11: Material composition at the inlet of the ammoniation reactor; 12: Ammoniation reaction products; 13: Circulating hydrogen and ammonia; 14: Circulating material (a mixture of aminohexanol-containing stream and cycloheximine-containing stream returned from the ammoniation reaction); 15: Hexamethylenediamine product; 16: Heavy components; 17: Material containing C12 amines; 19: Ammonolysis products; " / " in the table indicates a content of less than 500 ppm, or a content of 0.

[0067] Example 2

[0068] The method was carried out according to Example 1, except that 1,4-dioxane solvent was added to the ammonolysis reactor, the weight ratio of the solvent to the C12 amine-containing material was 2.1:1, and the weight ratio of the mixture of the aminohexanol-containing stream and the cycloheximine-containing stream returned to step (a) to the fresh hexanediol was 4.6:1.

[0069] The mass composition of each stream during stable reaction operation is shown in Table 2. The molar yield of hexamethylenediamine is 91.09%. The system is free from blockages and can operate continuously and stably for extended periods.

[0070] Table 2

[0071]

[0072]

[0073] Note: Same as Table 1.

[0074] Example 3

[0075] The method is carried out according to Example 1, except that the third separation is not performed in step (c), that is, the material containing C12 amine and heavy components directly enters the ammonolysis reactor for ammonolysis; the top material of the ammonolysis product obtained after separation by the coarse separation column in step (d) is returned to step (b), and the bottom material (heavy components) is directly discharged.

[0076] The mass composition of each stream during stable reaction operation is shown in Table 3. The molar yield of hexamethylenediamine was 90.75%.

[0077] Table 3

[0078]

[0079]

[0080] Note: Same as Table 1.

[0081] Example 4

[0082] The method was carried out according to Example 3, except that 1,4-dioxane solvent was added to the ammonolysis reactor, the weight ratio of the solvent to the material containing C12 amine and heavy components was 2:1, and the weight ratio of the mixture of aminohexanol-containing stream and cycloheximine-containing stream returned to step (a) to fresh hexanediol was 4.6:1.

[0083] The mass composition of each stream during stable reaction operation is shown in Table 4. The molar yield of hexamethylenediamine is 90.9%. The system is free from blockages and can operate continuously and stably for extended periods.

[0084] Table 4

[0085]

[0086] Note: Same as Table 1.

[0087] Compared to a process without ammonolysis, the methods in Examples 1-4 of this invention can increase the yield of hexamethylenediamine by more than 7%.

[0088] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing hexamethylenediamine by amination reaction, characterized in that, The method includes the following steps: (a) Hexanediol and ammonia undergo an ammoniation reaction under hydrogen-exposed conditions and in the presence of an ammoniation catalyst to obtain the ammoniation product; (b) The unreacted hydrogen and ammonia in the ammoniation reaction product are pre-separated to obtain a pre-separated product and a material containing hydrogen and ammonia, and the material containing hydrogen and ammonia is returned to step (a). (c) The pre-separation product is separated to obtain a material containing cyclohexylimine, hexamethylenediamine, aminohexanol, and a C12 amine; wherein part or all of the mixture of the material containing cyclohexylimine and / or the material containing aminohexanol is returned to step (a); the C12 amine includes bis(hexamethylene)triamine; (d) Under hydrogen-containing conditions, the material containing C12 amine and ammonia are contacted with the ammonolysis catalyst to obtain the ammonolysis reaction product. The ammonolysis reaction product is returned to step (b) with or without separation. The ammonolysis catalyst was prepared according to the following method: (1) Preparation of carrier: The mixture of boehmite, silica sol and calcium nitrate is contacted with an aqueous solution containing nitric acid and phosphoric acid, and then kneaded, dried and calcined in sequence; (2) The carrier is immersed in an aqueous solution containing nickel sulfate, lanthanum acetate and indium nitrate, dried at 100-140℃ for 2-6 hours, and then calcined at 350-450℃ for 2-6 hours; The weight ratio of the mixture of cyclohexylimine and / or aminohexanol-containing materials returned to step (a) to fresh hexanediol is 0.02-15:

1.

2. The method according to claim 1, wherein, In step (a), the molar ratio of ammonia to hexanediol is 15-42:1, and the molar ratio of hydrogen to hexanediol provided by the hydrogenation conditions is 0.09-8:

1.

3. The method according to claim 2, wherein, In step (a), the molar ratio of ammonia to hexanediol is 25-38:1, and the molar ratio of hydrogen to hexanediol provided by the hydrogenation conditions is 0.6-3.5:

1.

4. The method according to claim 1, wherein, The amination reaction temperature is 115-205℃; the amination reaction pressure is 6.5-17 MPaG; and the liquid hourly space velocity (LHSV) of fresh hexanediol is 0.08-6 h⁻¹. -1 .

5. The method according to claim 1, wherein, The ammoniation reaction occurs at temperatures ranging from 130 to 195°C and pressures ranging from 9 to 15 MPaG, with a liquid hourly space velocity (LHSV) of 0.1 to 3.8 h⁻¹ for fresh hexanediol. -1 .

6. The method according to claim 1, wherein, In step (b), the pre-separation conditions result in a hydrogen recovery rate of over 99% and an ammonia recovery rate of over 98%.

7. The method according to claim 1 or 6, wherein, In step (b), the pre-separation method is selected from at least one of flash evaporation, distillation separation and membrane separation.

8. The method according to claim 1, wherein, The methods for separating the pre-separated products include at least one of distillation, membrane separation, and pressure swing adsorption.

9. The method according to claim 1, wherein, The weight ratio of the mixture of materials containing cyclohexylimine and / or aminohexanol to fresh hexanediol in step (a) is 0.04-8:

1.

10. The method according to claim 1, wherein, The conditions for ammonolysis include: a reaction temperature of 135-255℃; a reaction pressure of 9.5-24 MPaG; and a liquid hourly space velocity (LHSV) of 0.05-8 h⁻¹ for the C12 amine-containing material. -1 The mass ratio of hydrogen provided by the hydrogen-containing conditions to C12 amine in the material containing C12 amine is 0.01-0.18:1; the mass ratio of ammonia to C12 amine in the material containing C12 amine is 3.6-12.5:

1.

11. The method according to claim 10, wherein, The conditions for ammonolysis include: a reaction temperature of 155-250℃; a reaction pressure of 10.5-22 MPaG; and a liquid hourly space velocity (LHSV) of 0.08-4 h⁻¹ for the C12 amine-containing material. -1 The mass ratio of hydrogen provided by the hydrogen-containing conditions to C12 amine in the material containing C12 amine is 0.02-0.13:1; the mass ratio of ammonia to C12 amine in the material containing C12 amine is 6.2-9.8:

1.

12. The method according to claim 1, wherein, In step (d), the C12 amine-containing material and ammonia are contacted with the ammonolysis catalyst in a solvent environment, the solvent including at least one of tetrahydrofuran, 1,4-dioxane, n-hexane, cyclohexane and tert-butanol.

13. The method according to claim 12, wherein, The weight ratio of solvent to C12 amine-containing material is 0.1-10:1.

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