A process for the synthesis of 3-aminomethyl-3,5,5-trimethylcyclohexylamine

Abstract

The application discloses a synthesis method of 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The method comprises the following steps: 1) taking 3-cyano-3,5,5-trimethylcyclohexylimine and hydrogen as raw materials, and performing imine hydrogenation reaction in a solvent in the presence of a first catalyst and a first cocatalyst to obtain 3-cyano-3,5,5-trimethylcyclohexylamine; 2) taking 3-cyano-3,5,5-trimethylcyclohexylamine and hydrogen as raw materials, and performing cyano hydrogenation reaction in an organic solvent in the presence of a second catalyst and a second cocatalyst to obtain a target product; the first catalyst contains one or both of nickel and cobalt; the first cocatalyst is a substance capable of reacting with hydrogen cyanide; the second catalyst contains iron; and the second cocatalyst is a Lewis acid catalyst. The synthesis method can obviously improve the yield and purity of the target product, the catalyst is more stable, the cost is lower, and the synthesis method is more environmentally friendly.

Description

A method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine Technical Field

[0001] This invention relates to a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. Background Technology

[0002] 3-Aminomethyl-3,5,5-trimethylcyclohexylamine, commonly known as isophorone diamine (IPDA), is usually prepared by hydrogenation of isophorone nitrile (chemical name 3-cyano-3,5,5-trimethylcyclohexanone), and the key to the hydrogenation reaction lies in the choice of catalyst.

[0003] Current technologies typically employ nickel and cobalt catalysts. However, hydrogen cyanide (HCN) is generated during the hydrogenation reaction, which is poisonous to these catalysts, leading to deactivation and a significant reduction in their lifespan. Furthermore, nickel and cobalt catalysts are heavy metal catalysts, resulting in high production costs and prices, and they are also not environmentally friendly.

[0004] The hydrogenation reaction produces 3-cyano-3,5,5-trimethylcyclohexylamine (IPAN) as a byproduct. In existing technologies, to control its content at a low level, the amount of catalyst is usually increased or the reaction time is extended; however, this is disadvantageous. The hydrogenation reaction also produces a high content of the bicyclic secondary amine TAO as a byproduct, which forms an azeotrope with water and isophorone diamine (IPDA), making it difficult to separate the target product.

[0005] Chinese patent CN101568516A discloses a method of reacting a feed stream containing 3-cyano-3,5,5-trimethylcyclohexylimine with hydrogen and ammonia in the presence of a hydrogenation catalyst. After partial reaction, the reaction mixture is contacted with a basic compound other than ammonia and / or with a basic catalyst to increase the basicity of the reaction mixture, thereby improving the yield of the isophorone diamine target product. However, the reaction product of this method contains a high content of the byproduct 3-cyano-3,5,5-trimethylcyclohexylamine (IPAN), whose boiling point is close to that of the isophorone diamine target product, making them difficult to separate and resulting in low purity of the target product.

[0006] US Patent 5756845A discloses a method for preparing isophorone diamine from isophorone. This method uses alkali metal hydroxides to modify the hydrogenation catalyst, thereby improving the yield of the target isophorone diamine product. By adding alkali metal hydroxides, especially lithium hydroxide, the yield of primary amines can be increased during the hydrogenation of isophorone nitrile, and the formation of secondary amine byproducts can be effectively suppressed. However, in practice, as time progresses, hydroxides gradually precipitate from the catalyst, leading to a further increase in the content of secondary amine byproducts, and poor catalyst stability. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an improved method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, which addresses the shortcomings and deficiencies of the prior art. This method significantly improves the yield and purity of the target product, uses a more stable catalyst that is less prone to deactivation, and is also cheaper and more environmentally friendly.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, the method comprising the following steps: 1) using 3-cyano-3,5,5-trimethylcyclohexylimine and hydrogen as raw materials, performing an imine hydrogenation reaction in a solvent in the presence of a first catalyst and a first co-catalyst to obtain 3-cyano-3,5,5-trimethylcyclohexylamine; 2) using the 3-cyano-3,5,5-trimethylcyclohexylamine and hydrogen as raw materials, performing a cyano hydrogenation reaction in an organic solvent in the presence of a second catalyst and a second co-catalyst to obtain the 3-aminomethyl-3,5,5-trimethylcyclohexylamine; wherein the first catalyst contains one or two selected from nickel and cobalt; the first co-catalyst is a substance capable of reacting with hydrogen cyanide; the second catalyst contains iron; and the second co-catalyst is a Lewis acid catalyst.

[0010] In the existing technology for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine via hydrogenation, nickel- or cobalt-based catalysts are typically used, and the yield of the target product is usually improved by modifying the catalyst. This hydrogenation reaction is a one-step reaction. Through careful research, the inventors of this invention discovered that the hydrogenation reaction of 3-cyano-3,5,5-trimethylcyclohexylimine (isophorone imine) with hydrogen is divided into two steps. Different first and second catalysts are used in each step. In the first step, by adding a substance capable of reacting with hydrogen cyanide (HCN) as a first co-catalyst, the poisoning effect of HCN produced by the decomposition of isophorone imine on the catalyst can be effectively suppressed, thereby improving the catalyst's stability. In the second step, by adding a Lewis acid catalyst as a second co-catalyst, the cyano group in the substrate 3-cyano-3,5,5-trimethylcyclohexylamine (IPAN) can be activated, significantly improving the reaction selectivity of the second step and significantly reducing the probability of the side reaction of intramolecular condensation of IPAN to form a bicyclic secondary amine (TAO), thereby further improving the yield and purity of the target product.

[0011] The reaction formula for the synthesis method of the present invention, which includes a two-step hydrogenation reaction, is as follows:

[0012]

[0013] In some embodiments, the first catalyst is a supported catalyst and includes a support, nickel, and cobalt; the first co-catalyst is selected from one or more combinations of aluminum trichloride, boron trifluoride, and trimethylaluminum.

[0014] In some embodiments, the carrier is selected from alumina or silicon oxide.

[0015] In some embodiments, the carrier is aluminum oxide.

[0016] In some embodiments, the alumina is prepared by the following method: dissolving a surfactant in water to obtain a surfactant solution, adding an aluminum salt solution to the surfactant solution, and then adding a precipitant dropwise to the surfactant solution for precipitation, aging, filtration, washing, drying, and calcination to obtain alumina.

[0017] In some embodiments, the surfactant is hexadecylammonium bromide.

[0018] In some embodiments, the aluminum salt is aluminum nitrate.

[0019] In some embodiments, the precipitant is sodium hydroxide.

[0020] In some embodiments, the mass of nickel is 40%-50% of the mass of the first catalyst, and the mass of cobalt is 20%-30% of the mass of the first catalyst.

[0021] In some embodiments, the mass of nickel is 42%-45% of the mass of the first catalyst, and the mass of cobalt is 25%-28% of the mass of the first catalyst.

[0022] In some embodiments, the mass of the support is 28%-33% of the mass of the first catalyst.

[0023] In some embodiments, the first catalyst is prepared by adding nickel salt and cobalt salt to a dispersion of a support for precipitation, calcination, and reduction.

[0024] In some embodiments, the nickel salt is selected from one or more combinations of nickel nitrate, nickel sulfate, and nickel chloride.

[0025] In some embodiments, the cobalt salt is selected from one or more combinations of cobalt nitrate, cobalt sulfate, and cobalt chloride.

[0026] In some embodiments, the support is alumina, and the first catalyst is prepared by the following method: dispersing the alumina support in acetone to obtain an alumina dispersion, adding a nickel salt solution and a cobalt salt solution to the alumina dispersion, adding a precipitant to precipitate, and then filtering, washing, drying, calcining and reducing to obtain the first catalyst.

[0027] In some embodiments, the calcination temperature is 200-450°C.

[0028] In some embodiments, the calcination time is 4-8 hours.

[0029] In some embodiments, the reduction is carried out in a hydrogen atmosphere.

[0030] In some embodiments, the reduction temperature is 400-600°C.

[0031] In some implementations, the restoration time is 3-5 hours.

[0032] In some embodiments, the support is silicon oxide, and the first catalyst is prepared by the following method: dispersing the silicon oxide support in an aqueous solution of an emulsifier to obtain a silicon oxide dispersion, adding a nickel salt solution and a cobalt salt solution to the silicon oxide dispersion, adding a precipitant to precipitate, and then filtering, washing, drying, calcining and reducing to obtain the first catalyst.

[0033] In some embodiments, the emulsifier is sodium dodecyl sulfonate.

[0034] In some embodiments, the precipitant is sodium silicate.

[0035] In some embodiments, the calcination temperature is 400-500°C.

[0036] In some embodiments, the calcination time is 4-8 hours.

[0037] In some embodiments, the reduction is carried out in a hydrogen atmosphere.

[0038] In some embodiments, the reduction temperature is 450-550°C.

[0039] In some implementations, the restoration time is 3-5 hours.

[0040] In some embodiments, the second catalyst is a supported iron catalyst; the second co-catalyst is aluminum isopropoxide. In this invention, an iron catalyst refers to a catalyst containing iron, which can be elemental iron (Fe), ferrous oxide (FeO), or a mixture of both.

[0041] In some embodiments, the support for the second catalyst is selected from alumina, silicon oxide, or magnesium oxide.

[0042] In some embodiments, the second catalyst contains 5%-20% iron by mass.

[0043] In some embodiments, the second catalyst contains 10%-15% iron by mass.

[0044] In some embodiments, the support for the second catalyst is silicon oxide, and the second catalyst contains 5%-20% iron and 40%-50% silicon by mass.

[0045] In some embodiments, the support for the second catalyst is silicon oxide, and the second catalyst contains 10%-15% iron and 40%-45% silicon by mass.

[0046] In some embodiments, the second catalyst is prepared by impregnating the support with a ferrous salt solution, drying, and reducing.

[0047] In some embodiments, the ferrous salt is ferrous acetate.

[0048] In some embodiments, the reduction is carried out in a hydrogen atmosphere.

[0049] In some embodiments, the reduction temperature is 600-1000°C.

[0050] In some implementations, the restoration time is 4-8 hours.

[0051] In some embodiments, the mass ratio of the first co-catalyst to 3-cyano-3,5,5-trimethylcyclohexylimine is 0.001-0.05:1.

[0052] In some embodiments, the mass ratio of the second co-catalyst to 3-cyano-3,5,5-trimethylcyclohexylimine is 0.005-0.1:1.

[0053] In some embodiments, the solvent described in step 1) and the organic solvent described in step 2) are both alcohol solvents, preferably ethanol.

[0054] In some embodiments, the temperature of the imine hydrogenation reaction is 120-140°C and the pressure is 25-30 MPa.

[0055] In some embodiments, the cyano hydrogenation reaction is carried out at a temperature of 140-160°C and a pressure of 25-30 MPa.

[0056] In some embodiments, the synthesis method includes the following steps: 1) adding 3-cyano-3,5,5-trimethylcyclohexylimine to a first reactor, introducing hydrogen gas into the first reactor, the first reactor being filled with the first catalyst; 2) adding a solution of the first co-catalyst to the first reactor to carry out the imine hydrogenation reaction, obtaining 3-cyano-3,5,5-trimethylcyclohexylamine; 3) adding the 3-cyano-3,5,5-trimethylcyclohexylamine to a second reactor, introducing hydrogen gas into the second reactor, the second reactor being filled with the second catalyst; 4) adding a solution of the second co-catalyst to the second reactor to carry out the cyano hydrogenation reaction, obtaining 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

[0057] In some embodiments, the mass concentration of the first co-catalyst solution is 3%-8%, preferably 5%.

[0058] In some embodiments, the mass concentration of the solution of the second co-catalyst is 5%-20%, preferably 10%-20%.

[0059] In some embodiments, the synthesis method further includes the step of reacting 3-cyano-3,5,5-trimethylcyclohexanone with liquid ammonia to generate the 3-cyano-3,5,5-trimethylcyclohexylimine.

[0060] In some embodiments, the synthesis method further includes the step of adding 3-cyano-3,5,5-trimethylcyclohexanone to a fixed-bed reactor and simultaneously introducing liquid ammonia into the fixed-bed reactor to carry out an imidization reaction, thereby preparing the 3-cyano-3,5,5-trimethylcyclohexylimine.

[0061] Compared with the prior art, the present invention has the following advantages:

[0062] This invention divides the hydrogenation reaction of 3-cyano-3,5,5-trimethylcyclohexylimine (isophorone imine) with hydrogen into two steps, using different first and second catalysts in each step. In the first step, a substance capable of reacting with hydrogen cyanide (HCN) is added as a first co-catalyst to effectively suppress the poisoning effect of HCN produced by the decomposition of isophorone imine on the catalyst, thereby improving catalyst stability. In the second step, a Lewis acid catalyst is added as a second co-catalyst to activate the cyano group in the substrate 3-cyano-3,5,5-trimethylcyclohexylamine (IPAN), significantly improving the selectivity of the second step hydrogenation reaction and significantly reducing the probability of intramolecular condensation of IPAN to form a bicyclic secondary amine (TAO), thus further improving the yield and purity of the target product.

[0063] The synthesis method of the present invention can achieve a yield of up to 98.9% of the target product 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The content of bicyclic secondary amine (TAO) impurity in the target product is less than 0.15%, the content of 3-cyano-3,5,5-trimethylcyclohexylamine (IPAN) impurity is less than 0.28%, and the content of 3,3,5-trimethylcyclohexylamine (TMCA) is less than 0.20%.

[0064] Existing technologies use nickel or cobalt-based catalysts that can catalyze both the double bond hydrogenation in the first step of the hydrogenation reaction and the cyano triple bond hydrogenation in the second step. This invention employs different catalysts for the double bond hydrogenation and cyano triple bond hydrogenation, respectively. For the first step of double bond hydrogenation, existing nickel or cobalt-based catalysts are used. However, for the second step of cyano triple bond hydrogenation, an iron-based catalyst with lower catalytic activity than nickel or cobalt-based catalysts is used. A Lewis acid catalyst is added as a second co-catalyst, which can activate the cyano group. Therefore, the iron-based catalyst can catalyze the second step of the hydrogenation reaction. Furthermore, iron is the most abundant substance in the Earth's crust, has low production costs, is environmentally friendly, and is less prone to poisoning. The catalyst of this invention showed no decrease in activity after continuous catalytic reaction for over 1500 hours, demonstrating good stability. Attached Figure Description

[0065] Figure 1 is a schematic diagram of the reaction process in Example 1. Detailed Implementation

[0066] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0067] Example 1

[0068] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The reaction flow chart is shown in Figure 1, and the specific steps are as follows:

[0069] The first step involves an imidization reaction between isophorone nitrile and liquid ammonia, using a fixed-bed reactor. The second step (the aforementioned first step hydrogenation reaction) and the third step (the aforementioned second step hydrogenation reaction) are carried out in the first reactor and the second reactor, respectively, both using trickle-bed reactors.

[0070] The first reactor is loaded with Al2O3-supported Ni and Co (Ni / Co) catalysts (wherein, by mass percentage, Ni accounts for 42% of the catalyst mass, Co accounts for 28% of the catalyst mass, and Al2O3 accounts for 30% of the catalyst mass), with a catalyst loading height of 90 mm and a diameter of 20 mm. The second reactor is loaded with SiO2-supported Fe and FeO (Fe / FeO) catalysts (wherein, by mass percentage, Fe element accounts for 12% of the catalyst mass, and Si element accounts for 40% of the catalyst mass), with a loading height of 90 mm and a diameter of 20 mm.

[0071] Liquid isophorone nitrile was added to the fixed-bed reactor at a rate of 1 g / min, and liquid ammonia was added at a rate of 2.1 g / min, both flowing concurrently. After an imidization reaction in the fixed-bed reactor, the resulting isophorone imine entered the first reactor. Simultaneously, hydrogen gas was continuously introduced into the first reactor, flowing concurrently with the isophorone imine. Additionally, a solution of a first co-catalyst, a 5% (w / w) AlCl3 ethanol solution, was continuously added to the first reactor at a feed rate of 0.1 g / min. The reaction pressure in the first reactor was 25 MPa, and the reaction temperature was 120 °C. After the imine hydrogenation reaction in the first reactor was completed, the reaction solution entered the second reactor. Simultaneously, hydrogen gas was continuously introduced into the second reactor, flowing concurrently with the above reaction solution. Additionally, a solution of a second co-catalyst, a 10% (w / w) aluminum isopropoxide ethanol solution, was continuously added to the second reactor at a feed rate of 0.1 g / min. The reaction pressure in the second reactor was 25 MPa, and the reaction temperature was 140 °C. After the reaction stabilized, samples were taken for gas chromatography analysis. The gas chromatography analysis conditions are as follows, and the results are shown in Table 1. TAO refers to the bicyclic secondary amine byproduct, IPAN refers to the 3-cyano-3,5,5-trimethylcyclohexylamine byproduct, TMCA refers to the 3,3,5-trimethylcyclohexylamine byproduct, and IPDA refers to the target product 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

[0072] Chromatographic column: CAM 30m × 0.32mm × 0.25μm

[0073] Inlet temperature: 280℃

[0074] Flow split ratio: 50:1

[0075] Column flow rate: 1 ml / min

[0076] Column temperature: 60℃, hold for 0 min, then increase to 200℃ at a rate of 20℃ / min, hold for 13 min.

[0077] Detector temperature: 300℃, H2 flow rate: 30ml / min, air flow rate: 400ml / min.

[0078] Examples 2-4

[0079] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 1, except that the temperatures and pressures of the first and second reactors are different, as detailed in Table 1 (where the pressure refers to the pressure of the first and second reactors being the same). After the reaction stabilizes, the same gas chromatography analysis as in Example 1 is performed, and the results are shown in Table 1.

[0080] Example 5

[0081] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 1, except that the catalyst support in the first reactor is replaced with SiO2 instead of Al2O3, and the temperatures and pressures of the first and second reactors are different, as detailed in Table 1. After the reaction stabilizes, the same gas chromatography analysis as in Example 1 is performed, and the results are shown in Table 1.

[0082] Example 6

[0083] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 1, except that the catalyst support in the second reactor is replaced with Al2O3 instead of SiO2, and the temperatures and pressures of the first and second reactors are different, as detailed in Table 1. After the reaction stabilizes, the same gas chromatography analysis as in Example 1 is performed, and the results are shown in Table 1.

[0084] Example 7

[0085] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 1, except that the catalyst support in the second reactor is replaced with MgO instead of SiO2, and the temperatures and pressures of the first and second reactors are different, as detailed in Table 1. After the reaction stabilizes, the same gas chromatography analysis as in Example 1 is performed, and the results are shown in Table 1.

[0086] Example 8

[0087] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 1, except that the mass concentration of the ethanol solution of aluminum isopropoxide, the second co-catalyst, is replaced with 5%, and the temperature and pressure of the first and second reactors are different, as detailed in Table 1. After the reaction stabilizes, the same gas chromatography analysis as in Example 1 is performed, and the results are shown in Table 1.

[0088] Example 9

[0089] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 1, except that the mass concentration of the ethanol solution of the second cocatalyst aluminum isopropoxide is replaced with 15%, and the temperature and pressure of the first and second reactors are different, as detailed in Table 1. After the reaction stabilizes, the same gas chromatography analysis as in Example 1 is performed, and the results are shown in Table 1.

[0090] Example 10

[0091] This embodiment provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 1, except that the mass concentration of the ethanol solution of aluminum isopropoxide, the second co-catalyst, is replaced with 20%, and the temperature and pressure of the first and second reactors are different, as detailed in Table 1. After the reaction stabilizes, the same gas chromatography analysis as in Example 1 is performed, and the results are shown in Table 1.

[0092] Table 1. Reaction conditions and chromatographic analysis results for Examples 1-10

[0093]

[0094] As shown in Table 1 above, the present invention can achieve high yield and high purity of the target product by using a two-step hydrogenation reaction and different catalysts and co-catalysts respectively.

[0095] Example 11

[0096] This embodiment tests the stability of the catalyst. The reaction scheme of Example 9 was used, and the reaction was carried out continuously for 1500 hours. Samples were taken for chromatographic analysis, using the same method as in Example 1. The results showed that the IPDA yield was 98.4%, the TAO content was 0.11%, the IPAN content was 0.05%, and the content of the byproduct 3,3,5-trimethylcyclohexylamine (TMCA) was 0.18%. It is evident that even after continuous catalysis for 1500 hours, the TMCA impurity content in the target product remained very low. This is because the first co-catalyst, AlCl3, effectively inhibits the hydrogenation of isophorone imine after decyanation to generate TMCA, and the activity of the first catalyst did not significantly decrease after 1500 hours of continuous catalysis, indicating strong catalyst stability.

[0097] Comparative Example 1

[0098] This comparative example provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 3, except that an ethanol solution of aluminum isopropoxide, the second cocatalyst, is not added to the second reactor. After the reaction stabilizes, samples are taken for chromatographic analysis, using the same method as in Example 1. The results show that the IPDA yield is 56.0%, the TAO content is 1.24%, the IPAN content is 40.8%, and the TMCA content is 1.84%. A comparison between Example 3 and Comparative Example 1 shows that the second cocatalyst, aluminum isopropoxide, can effectively activate the cyano group, thereby achieving better cyano hydrogenation.

[0099] Comparative Example 2

[0100] This comparative example provides a method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine. The specific steps are basically the same as in Example 11, except that an ethanol solution of aluminum chloride, the first co-catalyst, is not added to the first reactor. After 1500 hours of reaction, samples were taken for chromatographic analysis, using the same method as in Example 1. The results showed an IPDA yield of 94.8%, a TAO content of 0.58%, an IPAN content of 0.18%, and a TMCA content of 1.24%. A comparison between Example 11 and Comparative Example 2 shows that when the first hydrogenation reaction is not accompanied by the first co-catalyst, the catalytic activity of the first catalyst deteriorates, and the content of the byproduct TMCA increases significantly with time. This is because HCN produced by the decomposition of isophorone imine has a certain poisoning effect on the Al2O3-supported Ni / CO catalyst, while adding the first co-catalyst can inhibit this poisoning effect and increase catalyst stability.

[0101] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0102] 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.

Claims

1. A method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine, characterized in that: The synthesis method includes the following steps: 1) using 3-cyano-3,5,5-trimethylcyclohexylimine and hydrogen as raw materials, and in the presence of a first catalyst and a first co-catalyst, carrying out an imine hydrogenation reaction in a solvent to obtain 3-cyano-3,5,5-trimethylcyclohexylamine; 2) using the 3-cyano-3,5,5-trimethylcyclohexylamine and hydrogen as raw materials, and in the presence of a second catalyst and a second co-catalyst, carrying out a cyano hydrogenation reaction in an organic solvent to obtain the 3-aminomethyl-3,5,5-trimethylcyclohexylamine; the first catalyst is a supported catalyst, and includes... The catalyst comprises a support, nickel, and cobalt; the support is selected from alumina or silicon oxide; the mass of nickel is 40%-50% of the mass of the first catalyst, and the mass of cobalt is 20%-30% of the mass of the first catalyst; the first co-catalyst is selected from aluminum trichloride; the second catalyst is a supported iron catalyst; the support for the second catalyst is selected from alumina, silicon oxide, or magnesium oxide; the second catalyst contains 5%-20% iron by mass; the second co-catalyst is aluminum isopropoxide; the solvent in step 1) and the organic solvent in step 2) are both alcohol solvents.

2. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The first catalyst was prepared by adding nickel salt and cobalt salt to a dispersion of a support and then precipitating, calcining and reducing them.

3. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The second catalyst is supported on silicon oxide and contains 5%-20% iron and 40%-50% silicon by mass.

4. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The second catalyst was prepared by impregnating the support with a ferrous salt solution, drying, and reducing.

5. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The mass ratio of the first co-catalyst to 3-cyano-3,5,5-trimethylcyclohexylimine is 0.001-0.05:

1.

6. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The mass ratio of the second co-catalyst to 3-cyano-3,5,5-trimethylcyclohexylimine is 0.005-0.1:

1.

7. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The temperature of the imine hydrogenation reaction is 120-140℃, and the pressure is 25-30MPa.

8. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The cyano hydrogenation reaction is carried out at a temperature of 140-160℃ and a pressure of 25-30MPa.

9. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The synthesis method includes the following steps: 1) adding 3-cyano-3,5,5-trimethylcyclohexylimine to a first reactor, introducing hydrogen gas into the first reactor, and the first reactor being filled with the first catalyst; 2) adding a solution of the first co-catalyst to the first reactor to carry out the imine hydrogenation reaction, thereby obtaining 3-cyano-3,5,5-trimethylcyclohexylamine; 3) adding the 3-cyano-3,5,5-trimethylcyclohexylamine to a second reactor, introducing hydrogen gas into the second reactor, and the second reactor being filled with the second catalyst; 4) adding a solution of the second co-catalyst to the second reactor to carry out the cyano hydrogenation reaction, thereby obtaining 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

10. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 1, characterized in that: The synthesis method further includes the step of reacting 3-cyano-3,5,5-trimethylcyclohexanone with liquid ammonia to generate the 3-cyano-3,5,5-trimethylcyclohexylimine.

11. The method for synthesizing 3-aminomethyl-3,5,5-trimethylcyclohexylamine according to claim 9, characterized in that: The synthesis method further includes the steps of adding 3-cyano-3,5,5-trimethylcyclohexanone to a fixed-bed reactor and simultaneously introducing liquid ammonia into the fixed-bed reactor to carry out an imidization reaction, thereby preparing the 3-cyano-3,5,5-trimethylcyclohexylimine.

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