A nickel catalyst and a method for preparing the same

Abstract

The present application relates to a kind of nickel catalyst, preparation method.The nickel catalyst includes the structure formed by the chemical bond effect of metal-based active center and formate ligand, the metal-based active center is nickel, formate is combined with nickel with bidentate coordination structure;The nickel catalyst of the present application has higher cyclohexylamine yield, when realizing the conversion rate of 100% of cyclohexanone, the yield of product cyclohexylamine can be up to 96.45% at most;Preparation method is simple, catalyst preparation process is simple, easy to operate, and various aids do not need to be added in catalytic process, reduce the complexity of reaction system, it is favorable to the purification of product, suitable for industrial application.

Description

[0001] This application is application number CN202210234591.3, application date: 2022-03-09; title: A divisional application of a nickel catalyst, preparation method and application. Technical Field

[0002] This invention relates to a nickel catalyst and its preparation method. Background Technology

[0003] Cyclohexylamine (also known as hexahydroaniline or aminocyclohexane) is an important fine chemical intermediate with wide applications in the organic synthesis industry. It can be used to produce petroleum product additives, metal corrosion inhibitors, rubber vulcanization accelerators and antioxidants, food and feed additives, and other products. There are several industrial routes for synthesizing cyclohexylamine, such as...

[0004] (1) Aniline hydrogenation reduction method. This process is mature, the raw materials are readily available, and the selectivity is good. It is currently the most commonly used method for cyclohexylamine synthesis in China. However, the traditional production process of aniline, the raw material used in this process, will cause great pollution to the environment and the production cost is high, which indirectly affects the cost of cyclohexylamine prepared from aniline.

[0005] (2) Ammonolysis of chlorocyclohexane: This method has a long process route, poor selectivity of cyclohexylamine, and the reaction product contains hydrogen chloride, which requires high-quality equipment.

[0006] (3) Nitrocyclohexane reduction method: The raw material for this process route needs to be obtained by nitration of cyclohexane. The process is complicated and will cause great environmental pollution.

[0007] (4) Cyclohexanol and cyclohexanone catalytic ammonolysis method; Except for a few foreign companies that use cyclohexanol catalytic ammonolysis to produce cyclohexylamine, domestic manufacturers rarely use this route due to the lack of corresponding ammonolysis catalysts.

[0008] Currently, patent CN109647450A discloses a supported catalyst for the hydrogenation of aniline to cyclohexylamine, using phosphorus-modified alumina as a support, with Co and auxiliary elements as active components, achieving a cyclohexylamine yield of 81.58%; patent CN102633649A discloses a method for the gas-phase hydrogenation of aniline to synthesize cyclohexylamine, which can achieve low-temperature operation and increase the cyclohexylamine yield to 93%; patent CN101450903A uses phenol, which is relatively inexpensive and has no serious pollution during the preparation process, to replace the traditional raw material aniline, and produces cyclohexylamine under the catalysis of a palladium-based catalyst, achieving the best selectivity of 89.4%, but the reaction temperature is 150-260℃; in addition, there are also different methods for producing cyclohexylamine. Patent CN100528830C discloses a low-cost method for synthesizing cyclohexylamine from cyclohexanone oxime, with a yield of 85%.

[0009] The above methods can all achieve the synthesis of cyclohexylamine, but they have problems such as low yield and harsh reaction conditions. Summary of the Invention

[0010] This invention provides a nickel catalyst and its preparation method, which can effectively solve the above-mentioned problems.

[0011] This invention is implemented as follows:

[0012] The following scheme is adopted in the embodiments of the present invention: a nickel catalyst is provided, and the formate ion is modified in one step to achieve high selectivity for the reductive amination of cyclohexanone to prepare cyclohexylamine.

[0013] In one embodiment of the present invention, a structure is formed by chemical bonding between a metal-based active center and a formate ligand, wherein the metal-based active center is nickel, and the formate ligand is bonded to nickel in a bidentate coordination structure.

[0014] In one embodiment of the present invention, the nickel includes at least one of nickel ions, nickel single atoms, nickel nanoparticles, and nickel micron particles; the nickel particle size is 5 nm to 2 μm.

[0015] In one embodiment of the present invention, the nickel is loaded onto a support; the support includes at least one of activated carbon, silicon dioxide, alumina, molecular sieve, MOF, COF, kaolin, hydrotalcite, and magnesium oxide.

[0016] This invention also provides a method for preparing a nickel catalyst. The catalyst preparation process is simple and easy to operate. The catalytic process does not require the addition of various additives, reducing the complexity of the reaction system and facilitating product purification. It is suitable for industrial applications and includes the following preparation steps:

[0017] The nickel was dispersed in a mixed solution of organic solvent, water and formate precursor, and placed in a reaction vessel; nitrogen gas was introduced into the reaction vessel for heating and heat preservation, and after cooling, it was taken out, centrifuged and washed several times, and then vacuum dried to obtain the nickel catalyst; a nickel catalyst with high selectivity for the reductive amination of cyclohexanone to prepare cyclohexylamine can be obtained by one-step modification, and formic acid or formate salt is inexpensive and environmentally friendly.

[0018] In one embodiment of the present invention, the volume of the organic solvent is preferably 5 ml to 20 ml, and the volume of the water is preferably 2 ml to 20 ml; the mixing ratio of the organic solvent and water is 1:10 to 10:1; the organic solvent includes organic solvent and water, and the organic solvent includes at least one of benzene, toluene, phenol, DMF, NMP, DMSO, formamide, acetamide, dimethyl carbonate, monohydric alcohol, dihydric alcohol, and polyhydric alcohol.

[0019] In one embodiment of the present invention, the formate precursor includes at least one of formic acid and formate salt; the molar ratio of formic acid or formate salt to metallic nickel is 5:1 to 50:1.

[0020] In one embodiment of the present invention, the formate is selected from at least one of lithium formate, sodium formate, magnesium formate, aluminum triformate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, copper formate, barium formate, beryllium formate, nickel formate, cobalt formate, and manganese formate.

[0021] In one embodiment of the present invention, the heating temperature is 30-200℃, preferably 100-150℃, and the heat preservation time is 0.5h-24h, preferably 16h-20h.

[0022] The beneficial effects of this invention are as follows: This invention provides a nickel catalyst, a preparation method, and an application. Compared with the prior art, this invention has at least the following technical effects:

[0023] 1. High selectivity: For the catalytic reduction amination reaction of cyclohexanone, the yield of the product cyclohexylamine can reach up to 96.45% when 100% conversion of cyclohexanone is achieved, which solves the problem of generally low product yield in the existing technology.

[0024] 2. Low energy consumption: The nickel catalyst prepared by this invention makes the reaction temperature and gas pressure of the cyclohexylamine preparation process relatively mild, and can achieve high selectivity of cyclohexylamine at 50℃ and 1.0MPa hydrogen pressure, which solves the problem of harsh reaction conditions in the prior art.

[0025] 3. Universality: The formate-bonded nickel catalyst of the present invention is applicable to different types of nickel, including both nickel particles and supported nickel-based catalysts. It has high universality and can achieve high selectivity for cyclohexylamine.

[0026] Furthermore, the catalyst preparation method and cyclohexylamine preparation method provided by this invention are simple to operate, low in cost, environmentally friendly, and of extremely high quality. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a gas chromatogram of the product after the reaction of cyclohexanone as a substrate with a nickel catalyst.

[0029] Figure 2This is a scanning electron microscope image of the nickel nanoparticles prepared in Example 1.

[0030] Figure 3 The image shows the XRD characterization of the nickel nanoparticles prepared in Example 1.

[0031] Figure 4 This is a transmission electron microscope (TEM) image of the 20 wt% nickel-carbon catalyst prepared in Example 2.

[0032] Figure 5 The 20 wt% nickel-carbon catalyst prepared in Example 2 is characterized by XRD.

[0033] Figure 6 This is a comparison of the selectivity of cyclohexylamine using 20wt% nickel-carbon catalysts with different formate modification times.

[0034] Figure 7 This is the reaction formula for the catalyst prepared in this invention to be used in the cyclohexanone reduction amination reaction to obtain cyclohexylamine.

[0035] Figure 8 This is an in-situ infrared spectrum of formate ions bound to the surface of a nickel catalyst. Detailed Implementation

[0036] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0037] This invention provides a nickel catalyst comprising a structure formed by chemical bonding of a metal-based active center and a formate ligand, wherein the metal-based active center is nickel, and the formate ligand is bonded to nickel in a bidentate coordination structure.

[0038] In this embodiment of the invention, nickel includes at least one of nickel ions, nickel single atoms, nickel nanoparticles, and nickel micron particles.

[0039] In this embodiment of the invention, nickel can be loaded onto a support, which includes at least one of activated carbon, silicon dioxide, alumina, molecular sieve, MOF, COF, kaolin, hydrotalcite, and magnesium oxide.

[0040] This invention also provides a method for preparing a nickel catalyst, comprising the following steps:

[0041] 1) Disperse nickel in a mixed solution of organic solvent, water and formate precursor, and place it in a reaction vessel;

[0042] 2) Introduce nitrogen gas into the reactor, raise the temperature to 30–200°C, and maintain the temperature for 0.5–24 hours;

[0043] 3) After cooling, remove the catalyst, centrifuge and wash it, then vacuum dry it to obtain the nickel catalyst.

[0044] The organic solvent includes at least one of benzene, toluene, phenol, DMF, NMP, DMSO, formamide, acetamide, dimethyl carbonate, monohydric alcohol, dihydric alcohol, and polyhydric alcohol, including but not limited to these; the volume of the organic solvent is 5 ml to 20 ml, and the volume of water is 2 ml to 20 ml; the mixing ratio of the organic solvent to water is 1:10 to 10:1.

[0045] In embodiments of the present invention, formate may include at least one of lithium formate, sodium formate, magnesium formate, aluminum triformate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, copper formate, barium formate, beryllium formate, nickel formate, cobalt formate, and manganese formate; the molar ratio of formic acid or formate to nickel is 5:1 to 50:1.

[0046] The present invention also provides a method for preparing cyclohexylamine, comprising the following steps: adding 5 mL of solvent one, 1-10 mmol of cyclohexanone, and an ammonia source sequentially to a high-pressure reactor, then adding 0.1-1 mmol of the nickel catalyst prepared above, and mixing evenly; introducing hydrogen gas to carry out a hydrogenation reaction, maintaining the hydrogen pressure at 1-2 MPa, raising the temperature to 40-180°C, and reacting for a certain period of time to obtain a solution containing cyclohexylamine.

[0047] Solvent one includes at least one of methanol, ethanol, toluene, chloroform, acetonitrile, tetrahydrofuran, chlorobenzene, cyclohexane, decanane, and 1,4-dioxane, and is not limited to these; the ammonia source includes ammonia water or ammonia gas.

[0048] The present invention will be further described in detail below with reference to specific embodiments.

[0049] Example 1: Preparation of cyclohexylamine using nickel catalyst A

[0050] Weigh 60 mg of nickel nanoparticles (100-200 nm) and place them in a high-pressure reactor containing 1.2 g sodium formate, 5 mL ethylene glycol and 20 mL water. Purge the gas in the reactor with nitrogen. Then, heat to 100-150 °C and keep at that temperature for 6 h. Allow to cool naturally to room temperature. Wash several times with ultrapure water and anhydrous ethanol. Dry in a vacuum drying oven to obtain formate-modified nickel catalyst A with a particle size of 100-200 nm.

[0051] Synthesis of cyclohexylamine: 5 mL of solvent ethanol, 10 mmol of raw material cyclohexanone, 1 mL of ammonia, and 1 mmol of nickel catalyst A were added sequentially to a high-pressure reactor. After thorough mixing, hydrogen gas was introduced to replace the gas in the reactor, maintaining a hydrogen pressure of 0.8 MPa. The temperature was raised to 60°C, and after reacting for a certain period, a sample was taken and analyzed by gas chromatography. (See also...) Figures 1 to 3 Analysis showed that the conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 93.75%.

[0052] Comparative Example 1: Preparation of Cyclohexylamine from Nickel Nanoparticles

[0053] Synthesis of cyclohexylamine: 5 mL of ethanol, 10 mmol of cyclohexanone, 1 mL of ammonia, and 1 mmol of nickel nanoparticles (100-200 nm) were added sequentially to a high-pressure reactor. After thorough mixing, hydrogen gas was introduced to replace the gas in the reactor, maintaining a hydrogen pressure of 0.8 MPa. The temperature was raised to 60 °C, and after reacting for a certain period, samples were taken and analyzed by gas chromatography. Analysis showed that the conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 63.25%.

[0054] As can be seen from the comparison between Example 1 and Comparative Example 1, the nickel catalyst obtained by modifying nickel nanoparticles with formate in this invention has higher selectivity for catalyzing the reduction amination reaction of cyclohexanone to prepare cyclohexylamine.

[0055] Example 2: Preparation of cyclohexylamine using nickel catalyst B

[0056] Weigh 300 mg of supported 20 wt% nickel-carbon catalyst and place it in a high-pressure reactor containing 1.2 g sodium formate, 20 mL ethylene glycol and 2 mL water. Purge the gas in the reactor with nitrogen. Then, heat to 100-150 °C and keep at that temperature for 6 h. Allow it to cool naturally to room temperature. Wash it several times with ultrapure water and anhydrous ethanol and dry it in a vacuum drying oven to obtain formate-modified nickel catalyst B.

[0057] Synthesis of cyclohexylamine: 5 mL of solvent ethanol, 1 mmol of raw material cyclohexanone, 2 mL of ammonia, and 0.1 mmol of nickel catalyst B were added sequentially to a high-pressure reactor. After thorough mixing, hydrogen gas was introduced to replace the gas in the reactor, maintaining a hydrogen pressure of 1 MPa. The temperature was raised to 50 °C, and after reacting for a certain period, a sample was taken and analyzed by gas chromatography. (See also...) Figure 4 , Figure 5 Analysis showed that the conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 93.65%.

[0058] Example 3: Preparation of cyclohexylamine using nickel catalyst C

[0059] Weigh 300 mg of supported 20 wt% nickel-carbon catalyst and place it in a high-pressure reactor containing 1.2 g sodium formate, 20 mL ethylene glycol and 2 mL water. Purge the gas in the reactor with nitrogen, then heat to 100-150 °C and hold for 12 h. Allow it to cool naturally to room temperature, wash several times with ultrapure water and anhydrous ethanol, and dry in a vacuum drying oven to obtain nickel catalyst C.

[0060] Synthesis of cyclohexylamine: Compared with Example 2, the nickel catalyst B 0.1 mmol added in the synthesis of cyclohexylamine was replaced with nickel catalyst C 0.1 mmol. The rest of the experimental steps and conditions were the same as in Example 2. The conversion rate of cyclohexanone was 100% and the selectivity of cyclohexylamine was 94.75%.

[0061] Example 4: Preparation of cyclohexylamine using nickel catalyst D

[0062] Weigh 300 mg of supported 20 wt% nickel-carbon catalyst and place it in a high-pressure reactor containing 1.2 g sodium formate, 20 mL ethylene glycol and 2 mL water. Purge the gas in the reactor with nitrogen. Then, heat to 100-150 °C and keep at that temperature for 18 h. Allow it to cool naturally to room temperature, wash it several times with ultrapure water and anhydrous ethanol, and dry it in a vacuum drying oven to obtain nickel catalyst D.

[0063] Synthesis of cyclohexylamine: Compared with Example 2, the nickel catalyst B 0.1 mmol added in the synthesis of cyclohexylamine was replaced with nickel catalyst D 0.1 mmol. The rest of the experimental steps and conditions were the same as in Example 2. The conversion rate of cyclohexanone was 100% and the selectivity of cyclohexylamine was 95.36%.

[0064] Example 5: Preparation of cyclohexylamine using nickel catalyst D

[0065] Compared with Example 4, the difference is that the reaction temperature in the cyclohexylamine synthesis process was changed to 40°C. The rest of the experimental steps and conditions were the same as in Example 4. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 94.85%.

[0066] Example 6: Preparation of cyclohexylamine using nickel catalyst D

[0067] Compared with Example 4, the difference is that the reaction temperature in the cyclohexylamine synthesis process was changed to 60°C, while the rest of the experimental steps and conditions were the same as in Example 4. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 96.23%.

[0068] Comparative Example 2: Preparation of Cyclohexylamine using a Supported 20wt% Nickel-Carbon Catalyst

[0069] Synthesis of cyclohexylamine: 5 mL of ethanol, 1 mmol of cyclohexanone, 2 mL of ammonia, and 0.1 mmol of a 20 wt% nickel-carbon catalyst were added sequentially to a high-pressure reactor. After thorough mixing, hydrogen gas was introduced to replace the gas in the reactor, maintaining a hydrogen pressure of 1 MPa. The temperature was raised to 50 °C, and after reacting for a certain period, samples were taken and analyzed by gas chromatography. Analysis showed that the conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 85.76%.

[0070] Table 1. Conversion and selectivity of catalysts

[0071]

[0072] See Figures 1 to 5 As shown in Table 1, comparing Example 1 with Comparative Example 1, the nickel catalyst obtained by modifying nickel nanoparticles with formate ions in this invention exhibits higher selectivity for catalyzing the reductive amination reaction of cyclohexanone to prepare cyclohexylamine. (See also...) Figures 1 to 5 As shown in Table 1, comparing Examples 2, 3, and 4 with Comparative Example 2, it can be seen that the modification of the supported nickel-carbon catalyst with formate ions in this invention can effectively improve the selectivity of the cyclohexanone reductive amination reaction. (See also...) Figures 1 to 6 Referring to Table 1, different modification times were used in Examples 1, 3, and 4, showing that the preferred modification time is 18 hours, exhibiting the best catalytic performance. Referring to Table 1, different reaction temperatures were used in Examples 4, 5, and 6, showing that the preferred reaction temperature is 60°C, exhibiting the best cyclohexylamine selectivity.

[0073] Example 7: Preparation of cyclohexylamine using nickel catalyst A

[0074] Compared with Example 1, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was replaced with methanol. The rest of the experimental steps and conditions were the same as in Example 1. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 93.45%.

[0075] Example 8: Preparation of cyclohexylamine using nickel catalyst A

[0076] Compared with Example 1, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was changed to THF. The rest of the experimental steps and conditions were the same as in Example 1. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 92.63%.

[0077] Example 9: Preparation of cyclohexylamine using nickel catalyst A

[0078] Compared with Example 1, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was replaced with cyclohexane. The rest of the experimental steps and conditions were the same as in Example 1. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 92.89%.

[0079] Example 10: Preparation of cyclohexylamine using nickel catalyst A

[0080] Compared with Example 1, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was replaced with benzene. The rest of the experimental steps and conditions were the same as in Example 1. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 93.31%.

[0081] Example 11: Preparation of cyclohexylamine using nickel catalyst D

[0082] Compared with Example 4, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was replaced with methanol. The rest of the experimental steps and conditions were the same as in Example 4. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 95.12%.

[0083] Example 12: Preparation of cyclohexylamine using nickel catalyst D

[0084] Compared with Example 4, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was changed to THF. The rest of the experimental steps and conditions were the same as in Example 4. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 94.62%.

[0085] Example 13: Preparation of cyclohexylamine using nickel catalyst D

[0086] Compared with Example 4, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was replaced with cyclohexane. The rest of the experimental steps and conditions were the same as in Example 4. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 94.21%.

[0087] Example 14: Preparation of cyclohexylamine using nickel catalyst D

[0088] Compared with Example 4, the difference is that the reaction solvent ethanol in the cyclohexylamine synthesis process was replaced with benzene. The rest of the experimental steps and conditions were the same as in Example 4. The conversion rate of cyclohexanone was 100%, and the selectivity of cyclohexylamine was 95.18%.

[0089] Table 2 Conversion and selectivity under different reaction solvents

[0090]

[0091] Referring to Table 3, nickel catalysts were prepared using different molar ratios of formate to nickel in Examples 1, 15, 16, Comparative Example 1, 4, 17, 18, and Comparative Example 2. It can be seen that when nformate:nNi is 50:1, it has the best cyclohexylamine selectivity for catalyzing the reductive amination of cyclohexanone.

[0092] See Figure 3 , Figure 5 The X-ray diffraction patterns of the catalysts in Examples 1 and 2 demonstrate the synthesis of nickel and nickel-carbon compounds, based on the diffraction peaks in both patterns. (See also...) Figure 8By adsorbing formic acid onto the surface of nickel nanoparticles, it was observed that, compared to the infrared spectrum of formic acid alone, the hydroxyl signal disappeared after adsorption, indicating the breaking of the OH bond. The hydroxyl oxygen of the formate ion combines with Ni, and the wavenumber of C=O shifts from 1728 cm⁻¹ to 1749 cm⁻¹, indicating the interaction between the C=O bond and the Ni surface. This proves that the formate ion is bound to the nickel catalyst surface in a bidentate coordination manner. In summary, this invention achieves a high cyclohexylamine yield. The formate-modified nickel catalyst, for the reductive amination reaction of cyclohexanone, achieves a cyclohexanone conversion of 100% while yielding up to 96.45% of the cyclohexylamine product, which is beneficial for product separation and purification, and the reaction conditions are mild. The preparation method is simple: the catalyst preparation process is simple and easy to operate, and the catalytic process does not require the addition of various additives, reducing the complexity of the reaction system and facilitating product purification, making it suitable for industrial applications.

[0093] Finally, the above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A process for the preparation of cyclohexylamine, characterized in that: A high-pressure reaction kettle is sequentially added with a solvent I, cyclohexanone and an ammonia source, then a nickel catalyst is added, and mixed uniformly; hydrogen is introduced for hydrogenation reaction, and a solution containing cyclohexylamine is obtained after reaction for a period of time; the solvent I includes at least one of methanol, ethanol, toluene, chloroform, acetonitrile, tetrahydrofuran, chlorobenzene, cyclohexane and 1,4-dioxane, and the ammonia source includes ammonia water or ammonia gas; The nickel catalyst includes a structure formed by a metal-based active center and a formate ligand through chemical bonding, the metal-based active center is nickel, and the formate is combined with nickel in a bidentate coordination structure; The preparation method of the nickel catalyst includes the following preparation steps: 1) dispersing nickel in a mixed solution of an organic solvent, water and a formate precursor, and placing in a reaction kettle, the nickel includes at least one of nickel nanoparticles and nickel microparticles, and the formate precursor is formate; the molar ratio of the formate to nickel is 5:1-50:1; 2) introducing nitrogen into the reaction kettle, heating and keeping warm, the heating temperature is 100-150℃, and the keeping warm time is 16h-20h; 3) after cooling, taking out, centrifugal washing and vacuum drying to obtain the nickel catalyst.

2. A process for the preparation of cyclohexylamine according to claim 1, characterized in that: The organic solvent includes at least one of benzene, toluene, phenol, DMF, NMP, DMSO, formamide, acetamide, dimethyl carbonate, monohydric alcohol and polyhydric alcohol.

3. A process for the preparation of cyclohexylamine according to claim 2, characterized in that: The organic solvent is 5-20ml, the water is 2-20ml, and the mixing ratio of the organic solvent to water is 1:10-10:

1.

4. The process for the preparation of cyclohexylamine according to claim 1, characterized in that: The formate includes at least one of lithium formate, sodium formate, magnesium formate, aluminum triformate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, copper formate, barium formate, beryllium formate, nickel formate, cobalt formate and manganese formate.

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