CN117624087A

CN117624087A - Method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds

Info

Publication number: CN117624087A
Application number: CN202311298115.9A
Authority: CN
Inventors: 李瑞祥; 徐嘉麒; 杨思恒; 陈燕; 陈华; 郑学丽; 付海燕
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2023-10-08
Filing date: 2023-10-08
Publication date: 2024-03-01

Abstract

The invention discloses a method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds, which comprises the following preparation processes: aldehyde, ketone or alcohol compounds are mixed with an amine source, a reducing agent, a solvent and an inexpensive metal heterogeneous catalyst in a reactor, and the corresponding primary amine compounds are obtained through reductive amination reaction. The preparation method provided by the invention has the advantages that the application range of the substrate is wide, various aldehyde, ketone and alcohol compounds can be efficiently and highly selectively subjected to indirect or direct reductive amination to obtain corresponding primary amine, meanwhile, the catalyst has good cycling stability, and the synthetic raw materials are low in cost, easy to obtain and high in economical efficiency.

Description

Method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds

Technical Field

The invention relates to the technical field of heterogeneous catalysis and organic synthesis, in particular to a method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds.

Background

Amine is an important organic matter, wherein primary amine has active amino functional groups, and is widely used as an important chemical raw material for producing plastics, dyes, surfactants, medicines and other chemicals.

The synthesis method of primary amine mainly comprises the following steps: direct amination of alcohol compounds, reductive amination of aldehyde or ketone, hydrogenation reduction of nitrile compounds, hydrogenation reduction of nitro compounds, ammonolysis of halogenated hydrocarbon, addition of olefin and ammonia, and the like. The primary amine is synthesized by reductive amination of aldehyde, ketone and alcohol compounds, and the primary amine has become one of research hotspots for primary amine synthesis due to the characteristics of wide substrate sources, simple operation, high atom economy and the like. Reductive amination of aldehydes/ketones/alcohols is classified into direct reductive amination and indirect reductive amination depending on whether imine or imine ion intermediates are isolated. The indirect reductive amination reaction process requires multiple steps, so that the whole reaction process is extremely complicated, most imine intermediates are extremely unstable and difficult to separate, the yield of reductive amination is not ideal, the substrate is limited, and the industrial production is not facilitated finally. Therefore, the direct reductive amination process is relatively greener, simple and economical from the synthetic route, and is favored by researchers. However, there are side reactions such as hydrogenation competition of the raw material substrate and the imine intermediate, condensation of the product primary amine with the raw material substrate, etc. during the direct reductive amination reaction, so that the selectivity of primary amine preparation by this route is poor.

Catalysts for reductive amination of aldehydes/ketones/alcohols are largely divided into homogeneous catalysts and heterogeneous catalysts. Although primary amine can be obtained in high yield in a homogeneous catalysis mode, the problems of difficult separation of the catalyst, low reuse rate, the need of post-treatment of reaction liquid and the like exist; the heterogeneous catalyst has the advantages of easy separation, recycling and the like, and has great potential in industrial production. At present, noble metal (Ru, rh, pd, pt and the like) supported heterogeneous catalysts are widely applied to the production of primary amine by the reductive amination of large-scale aldehyde/ketone/alcohol compounds, but the defects of high production cost, loss and inactivation of active metal components, low primary amine selectivity and the like still exist. So, at present, more and more people begin to research the application of the cheap metal heterogeneous catalyst in reductive amination. However, the cheap metal heterogeneous catalyst is easy to be corroded by ammonia gas and the like, so that the catalyst is deactivated, the stability is poor, and the industrial application is not facilitated.

Therefore, it is a very challenging and interesting task to develop a heterogeneous catalytic process for the reductive amination of aldehyde/ketone/alcohol compounds with high selectivity, activity and stability to produce primary amines.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds, which is used for solving the problems of high production cost of the catalyst, loss and inactivation of active metal components, low selectivity and yield of primary amine products and the like in the reductive amination reaction of aldehyde/ketone/alcohol compounds in the prior art.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

a method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds is provided, reaction substrates (aldehyde, ketone or alcohol compounds) are mixed with an amine source, a reducing agent, a solvent and a heterogeneous catalyst in a reactor, and the corresponding primary amine compounds are obtained through direct or indirect reductive amination reaction.

Further, the mol ratio of the reaction substrate, the amine source, the reducing agent and the heterogeneous catalyst is (0-2000): 0-2000: (0-2000).

Further, the reaction substrate is at least one of fatty aldehyde, fatty ketone, fatty alcohol or aldehyde, ketone or alcohol compound containing benzene ring or heterocycle.

Further, the amine source is at least one of ammonia water, ammonia gas, ammonium acetate and hydroxylamine hydrochloride; the reducing agent is at least one of hydrogen, sodium borohydride, lithium borohydride and potassium borohydride; the solvent is at least one of ethanol, methanol, water, n-butanol, tetrahydrofuran and acetonitrile.

Further, the heterogeneous catalyst is an inexpensive metal catalyst coated with a non-metal element double-doped carbon nanotube.

Further, the cheap metal salt is at least one of ferric nitrate, ferric acetylacetonate, cobalt nitrate, cobalt acetylacetonate, cobalt acetate, nickel nitrate, nickel acetylacetonate and nickel acetate; the doped nonmetallic source is at least one of triphenylphosphine, thiourea and boric acid.

Further, the method specifically comprises the following steps:

preparation of S1 heterogeneous catalyst

Dispersing one or more cheap metal salts in a solvent, and obtaining cheap metal (or alloy thereof) nano particles through solvothermal reaction; then mixing the cheap metal (or alloy thereof) nano particles with a nitrogen source, a carbon source and a doped non-metal element source, taking the metal (or alloy thereof) nano particles as a template agent and generating a guiding agent, and carrying out pyrolysis under the protection of argon to obtain the non-metal element double-doped carbon nano tube coated cheap metal (or alloy thereof) heterogeneous catalyst;

s2 catalytic reduction amination reaction

The reaction substrate, an amine source, a reducing agent, a solvent and a heterogeneous catalyst are mixed in a reactor, and the corresponding primary amine compound is obtained through reductive amination reaction.

Further, in S1, the molar ratio of the cheap metal or alloy nano particles, the nitrogen source, the carbon source and the doped nonmetallic element source is (0-10000): (0-10000).

Further, in S1, the temperature of the solvothermal reaction is 100-350 ℃ and the reaction time is 1-5 h; the pyrolysis temperature of the catalyst prepared by pyrolysis is 500-1200 ℃, the reaction time is 1-5 h, and the heating rate is 1-10 ℃/min.

Further, in S2, the reaction temperature is 50-200 ℃, the reaction time is 1-24 h, and the pressure in the reactor is 0.1-10 MPa.

The beneficial effects of the invention are as follows:

(1) The method for preparing the primary amine by catalyzing the reductive amination of the aldehyde, ketone and alcohol compounds has wide application range of the substrate, and can be efficiently and highly selectively used for preparing the primary amine by indirect or direct reductive amination of various aldehydes, ketones and alcohols.

(2) The heterogeneous catalyst used in the invention takes cheap metal as an active component, which is beneficial to the reduction of the preparation cost of the catalyst.

(3) The invention utilizes the strategy of coating metal particles by the carbon nano tubes, so that the heterogeneous catalyst is more stable under the reaction condition, and active components are not easy to run off.

(4) According to the heterogeneous catalyst provided by the invention, the carbon nanotube carrier has the characteristic of double doping of nonmetallic elements, and the electronic structure of the surface of the catalyst can be regulated and controlled according to different electronegativity of nonmetallic elements so as to control the adsorption capacity of a substrate or an intermediate and active sites of the surface of the catalyst, thereby improving the selectivity of the catalyst to a product.

(5) The invention can adjust the corrosion resistance of the metal particles by adjusting the composition of the metal particles, regulate and control the electronic structure of the metal particles, and optimize the activity and stability of reductive amination of the metal particles.

(6) The catalyst obtained by the invention is a heterogeneous catalyst, is easy to separate the product from the catalyst after reaction and can be recycled for multiple times, and has the potential of large-scale production.

Drawings

FIG. 1 is a transmission electron microscope image of the metal nanoparticles prepared in example 1;

FIG. 2 is a transmission electron micrograph of the heterogeneous catalyst prepared in example 1; wherein 2a, 2b and 2c are transmission electron microscope pictures of the cheap metal catalyst coated by the nonmetallic element double-doped carbon nano tube;

FIG. 3 is an X-ray photoelectron spectrum (full spectrum) of the heterogeneous catalyst prepared in example 1;

FIG. 4 is an X-ray photoelectron spectrum (fine spectrum) of the core levels of Ni 2p, N1 s and B1s of the heterogeneous catalyst prepared in example 1;

FIG. 5 is a diagram of the product 1, 4-furandimethylamine prepared in example 1 ¹ H NMR spectrum;

FIG. 6 is a diagram of the product 1, 4-furandimethylamine prepared in example 1 ¹³ C NMR spectrum;

FIG. 7 is a graph showing the experimental performance of the cycle stability in example 31.

Detailed Description

The following description of the embodiments of the present invention is provided to facilitate understanding of the present invention by those skilled in the art, but it should be understood that the present invention is not limited to the scope of the embodiments, and all the inventions which make use of the inventive concept are protected by the spirit and scope of the present invention as defined and defined in the appended claims to those skilled in the art.

Example 1

The embodiment provides a method for preparing primary amine by catalyzing direct reductive amination of aldehyde, ketone and alcohol compounds, which comprises the following steps:

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles, 600 parts of melamine and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, placing the powder into a vacuum drying oven for drying at 70 ℃, and obtaining the catalyst which is denoted as Co-N, B-CNT.

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 95.4%).

Example 2

s1, adding 1 part of ferric nitrate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. Centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain the iron nano particles. Dispersing 2 parts of iron nano particles, 600 parts of melamine and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, placing the powder into a vacuum drying oven for drying at 70 ℃, and obtaining the catalyst which is marked as Fe-N, B-CNT.

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 73.0%).

Example 3

s1, adding 1 part of nickel acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain the nickel nano particles. Dispersing 2 parts of nickel nano particles, 600 parts of melamine and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Ni-N, B-CNT.

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 81.2%).

Example 4

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles, 600 parts of melamine and 10 parts of thiourea in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove the ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, placing the powder into a vacuum drying oven for drying at 70 ℃, and obtaining the catalyst which is denoted as Co-N, S-CNT.

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 89.4%).

Example 5

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles, 600 parts of melamine and 10 parts of triphenylphosphine in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Co-N, P-CNT.

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 96.0%).

Example 6

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde, 10 parts of ammonium acetate and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 90.3%).

Example 7

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde, 10 parts of hydroxylamine hydrochloride and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 91.7%).

Example 8

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde and 1 part of catalyst in 100 parts of ethanol, adding into a reaction kettle, replacing gas in the kettle with nitrogen, filling ammonia gas at 0.5MPa, filling hydrogen gas to 3.5MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2, 5-furan dimethylamine (yield 95.2%).

Example 9

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling ammonia gas at 0.5MPa, filling hydrogen gas to 3.5MPa, sealing, and reacting at 180 ℃ for 1h to obtain 2, 5-furan dimethylamine (yield 93.9%).

Example 10

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling ammonia gas at 0.5MPa, filling hydrogen gas to 3.5MPa, sealing, and reacting at 100 ℃ for 5 hours to obtain 2, 5-furan dimethylamine (yield 95.0%).

Example 11

S2, dispersing 1 part of 2, 5-furan dicarboxaldehyde and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling ammonia gas at 0.5MPa, filling hydrogen gas to 3.5MPa, sealing, and reacting at 60 ℃ for 10 hours to obtain 2, 5-furan dimethylamine (yield 76.7%).

Example 12

S2, dispersing 1 part of terephthalaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain the terephthalamide (yield 96.8%).

Example 13

S2, dispersing 1 part of 5-hydroxymethylfurfural, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furandimethylamine (yield 96.7%).

Example 14

S2, dispersing 1 part of benzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 2.0MPa, sealing, and reacting at 140 ℃ for 3 hours to obtain benzylamine (yield 92.6%).

Example 15

S2, dispersing 1 part of p-methoxybenzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 5.0MPa, sealing, and reacting at 140 ℃ for 1.5 hours to obtain the p-methoxybenzylamine (yield 96.7%).

Example 16

S2, dispersing 1 part of p-methylbenzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain the p-methylbenzylamine (yield 92.5%).

Example 17

S2, dispersing 1 part of o-methylbenzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain o-methylbenzylamine (yield 90.2%).

Example 18

S2, dispersing 1 part of o-fluorobenzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 5.0MPa, sealing, and reacting at 160 ℃ for 3 hours to obtain the o-fluorobenzylamine (yield 96.1%).

Example 19

S2, dispersing 1 part of m-chlorobenzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 180 ℃ for 3 hours to obtain m-chlorobenzylamine (yield 95.8%).

Example 20

S2, dispersing 1 part of p-bromobenzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 160 ℃ for 5 hours to obtain the p-bromobenzylamine (yield 92.5%).

Example 21

S2, dispersing 1 part of m-trifluoromethyl benzaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 180 ℃ for 3 hours to obtain m-trifluoromethyl benzylamine (yield 91.8%).

Example 22

S2, dispersing 1 part of m-furfural, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 3.5MPa, sealing, and reacting at 180 ℃ for 3 hours to obtain furfuryl amine (yield 90.0%).

Example 23

S2, dispersing 1 part of 4-pyridine formaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 10 hours to obtain 4-aminomethylpyridine (yield 90.2%).

Example 24

S2, dispersing 1 part of 2-thiophenecarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 2-aminomethylthiophene (yield is 85.9%).

Example 25

S2, dispersing 1 part of acetophenone, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 160 ℃ for 20 hours to obtain phenethylamine (yield is 85.5%).

Example 26

S2, dispersing 1 part of 1, 4-cyclohexanedione, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-cyclohexanediamine (yield 83.4%).

Example 27

S2, dispersing 1 part of benzyl alcohol, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain benzylamine (yield 93.5%).

Example 28

S2, dispersing 1 part of 1-phenethyl alcohol, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting for 2 hours at 140 ℃ to obtain phenethyl amine (yield 71.4%).

Example 29

s1, adding 1 part of cobalt acetate and 5 parts of nickel acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. Centrifugally separating, washing the precipitate with cyclohexane, and then vacuum drying to obtain the nickel-cobalt alloy nano particles. Dispersing 2 parts of nickel-cobalt alloy nano particles, 600 parts of melamine and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely NiCo-N, B-CNT.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 94.5%).

Example 30

s1, adding 1 part of cobalt acetate and 5 parts of ferric nitrate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. Centrifugally separating, washing the precipitate with cyclohexane, and vacuum drying to obtain the Fe-Co alloy nanometer particle. Dispersing 2 parts of iron-cobalt alloy nano particles, 600 parts of melamine and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely FeCo-N, B-CNT.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 90.2%).

Example 31 (cycle stability test)

This example provides a process for the preparation of primary amines by direct reductive amination of catalytic aldehydes, ketones and alcohols, which process is exactly the same as in example 1.

After undergoing one complete catalytic cycle as in example 1, the reaction solution was centrifuged to obtain a catalyst solid, which was then washed several times with water and dried in vacuo at 70 ℃. The dried catalyst is then used again. The catalytic activity and stability were tested and the number of cycles was counted.

Comparative example 1

The comparative example provides a method for preparing primary amine by catalyzing direct reductive amination of aldehyde, ketone and alcohol compounds, comprising the following steps:

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles and 600 parts of melamine in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing the obtained powder uniformly, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Co-N-CNT.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 68.4%).

Comparative example 2

s1, adding 1 part of nickel acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain the nickel nano particles. Dispersing 2 parts of nickel nano particles and 600 parts of melamine in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under argon atmosphere at a heating rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Ni-N-CNT.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 42.6%).

Comparative example 3

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles and 600 parts of ketjen black powder in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Co@C.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 38.0%).

Comparative example 4

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles, 600 parts of ketjen black powder, 50 parts of urea and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tubular furnace, pyrolyzing the powder at 800 ℃ for 2 hours under argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst which is denoted as Co@N, B-C.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 29.3%).

Comparative example 5

s1, adding 1 part of cobalt nitrate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles, 600 parts of melamine and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 800 ℃ for 2 hours under an argon atmosphere, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, placing the powder into a vacuum drying oven for drying at 70 ℃, and obtaining the catalyst which is denoted as Co-N, B-CNT-NO.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 95.3%).

Comparative example 6

s1, adding 1 part of cobalt nitrate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles, 600 parts of melamine and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing into a tube furnace, pyrolyzing at 800 ℃ for 2 hours under an argon atmosphere, heating at a rate of 2 ℃/min, naturally cooling to room temperature, washing the obtained powder with dilute hydrochloric acid and deionized water in sequence, and then placing into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Co-N, B-CNT-acac.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 93.8%).

Comparative example 7

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles and 10 parts of thiourea in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 1000 ℃ for 2 hours under the atmosphere of methane gas, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Co-S-CNT.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 27.3%).

Comparative example 8

s1, adding 1 part of cobalt acetate into 10 parts of oleylamine, stirring and dispersing uniformly, and then heating the obtained solution to 300 ℃ and keeping for 1h; then, naturally cooling to room temperature, adding 40 parts of ethanol, and precipitating. And (3) centrifugally separating, washing the precipitate with cyclohexane, and then drying in vacuum to obtain cobalt nano particles. Dispersing 2 parts of cobalt nano particles and 10 parts of boric acid in 40 parts of ethanol, stirring and mixing uniformly, rotationally evaporating to remove ethanol, grinding and mixing uniformly the obtained powder, placing the powder into a tube furnace, pyrolyzing the powder at 1000 ℃ for 2 hours under the atmosphere of methane gas, heating the powder at a rate of 2 ℃/min, naturally cooling the powder to room temperature, washing the powder with dilute hydrochloric acid and deionized water in sequence, and then placing the powder into a vacuum drying oven for drying at 70 ℃ to obtain the catalyst, namely Co-B-CNT.

S2, dispersing 1 part of 1, 4-furan dicarboxaldehyde, 10 parts of ammonia water and 1 part of catalyst in 100 parts of ethanol, adding the mixture into a reaction kettle, replacing gas in the kettle with nitrogen, filling hydrogen to 4.0MPa, sealing, and reacting at 140 ℃ for 2 hours to obtain 1, 4-furan dimethylamine (yield 35.6%).

Test examples

1. TEM image of metal nanoparticles

From fig. 1, it is seen that the morphology of the metal nanoparticles is relatively uniform, and the average particle diameter is about 29.1nm.

2. TEM image of catalyst

As can be seen from fig. 2a-2b, the nanotubes in the micro morphology of the catalyst tightly cover the metal particles, so that sintering or agglomeration of the metal particles in the high temperature calcination process is avoided, and the carbon nanotube coating also plays a role in dispersing metal active sites. The high resolution transmission electron microscopy image in fig. 2c shows lattice fringes of the coated metal particles, wherein crystal plane spacing of 0.20 and 0.17nm crystal planes exist, corresponding to (111) and (200) crystal planes of cobalt metal respectively, which proves that the structure of the metal nano particles is not changed significantly during the pyrolysis process.

XPS spectrogram

As can be seen from fig. 3-4, ni (0) and Ni (ii) are present on the surface of the Ni-N, B-CNT catalyst, where Ni (0) is attributable to the presence of metallic nickel nanoparticles and Ni (ii) is attributable to the oxidation of metallic nickel. Meanwhile, the existence of nonmetallic elements N and B can be obviously seen on the XPS narrow spectrum, which shows the success of nonmetallic element double doping.

4. Reductive amination efficiency of nonmetallic element double-doped carbon nano tube coated low-cost metal (or alloy) catalyst

TABLE 1 comparative reductive amination Performance of different types of carbon-coated Metal catalysts

Table 1 shows a comparison of the catalytic efficiency of different types of carbon-coated metal catalysts in a direct reductive amination reaction of 1, 4-furandicarboxaldehyde. Under the same reaction conditions, the catalytic performance of the nonmetallic element double-doped carbon nano tube coated metal catalyst (examples 1-5) for directly carrying out reductive amination on 1, 4-furandicarboxaldehyde to 1, 4-furandimethylamine is obviously higher than that of the single nitrogen element doped carbon nano tube coated metal catalyst (comparative examples 1-4). The doping sites of various nonmetallic elements not only can adjust the electronic structure of the surface of the catalyst, but also can adjust and control the adsorption and desorption rate of reactants or reaction intermediates on the surface sites of the catalyst, thereby improving the activity and selectivity of the catalytic reaction. Furthermore, the single doping of nitrogen element (comparative examples 1 to 2) has higher activity and yield in the production of primary amine by catalytic reductive amination as compared with the single doping of S, B and the like (comparative examples 7 to 8). In addition, the catalytic effect of the carbon nanotube-coated metal catalysts (examples 1 to 5 and comparative examples 1 to 2) was also much higher than that of the ordinary carbon-coated metal catalysts (comparative examples 3 to 4), which may be attributed to the special morphology of the carbon nanotubes. Meanwhile, since the cobalt-based catalyst is the best among inexpensive metals, heterogeneous catalysts prepared based on different metal cobalt salt precursors can efficiently and highly selectively achieve reductive amination reactions (example 1 and comparative examples 5 to 6). Therefore, in order to promote the catalytic reduction amination activity of other cheap metals, the invention also prepares a cobalt-containing alloy heterogeneous catalyst for reductive amination experiments (examples 29-30), and Co metal is introduced on the basis of the original Ni and Fe-based multi-phase catalyst, so that the catalytic activity of the cobalt-containing alloy heterogeneous catalyst is greatly enhanced.

5. Cycling stability experiment

As can be seen from fig. 7, the primary amine yield is greater than 90% as the cycle number increases, which indicates that the catalyst and the catalytic method used in the present invention have ideal stability to some extent.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.

Claims

1. A method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds is characterized in that reaction substrates of aldehyde, ketone or alcohol compounds, an amine source, a reducing agent, a solvent and a heterogeneous catalyst are mixed in a reactor, and the corresponding primary amine compounds are obtained through direct or indirect reductive amination reaction.

2. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to claim 1, wherein the molar ratio of the reaction substrate, the amine source, the reducing agent and the heterogeneous catalyst is (0-2000): 0-2000.

3. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to claim 1, wherein the reaction substrate is at least one of fatty aldehyde, fatty ketone, fatty alcohol or aldehyde, ketone or alcohol compound containing benzene ring or heterocycle.

4. The method for preparing primary amine by catalyzing the reductive amination of aldehyde, ketone and alcohol compounds according to claim 1, wherein the amine source is at least one of ammonia water, ammonia gas, ammonium acetate and hydroxylamine hydrochloride; the reducing agent is at least one of hydrogen, sodium borohydride, lithium borohydride and potassium borohydride; the solvent is at least one of ethanol, methanol, water, n-butanol, tetrahydrofuran and acetonitrile.

5. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to claim 1, wherein the heterogeneous catalyst is a cheap metal catalyst coated by non-metal element double-doped carbon nano tubes.

6. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to claim 5, wherein the cheap metal salt is at least one of ferric nitrate, ferric acetylacetonate, cobalt nitrate, cobalt acetylacetonate, cobalt acetate, nickel nitrate, nickel acetylacetonate and nickel acetate; the doped nonmetallic source is at least one of triphenylphosphine, thiourea and boric acid.

7. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to any one of claims 1 to 6, which comprises the following steps:

preparation of S1 heterogeneous catalyst

Dispersing one or more cheap metal salts in a solvent, and obtaining the cheap metal and alloy nano particles thereof through solvothermal reaction; mixing cheap metal or alloy nano particles thereof with a nitrogen source, a carbon source and a doped non-metal element source, taking the metal or alloy nano particles thereof as a template agent and generating a guiding agent, and carrying out pyrolysis under the protection of argon to obtain a non-metal element double-doped carbon nano tube coated cheap metal or alloy heterogeneous catalyst thereof;

S2 catalytic reduction amination reaction

8. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to claim 7, wherein in S1,

the molar ratio of the cheap metal and the alloy nano particles, the nitrogen source, the carbon source and the doped non-metal element source is (0-10000).

9. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to claim 7, wherein in S1,

the temperature of the solvothermal reaction is 100-350 ℃ and the reaction time is 1-5 h; the pyrolysis temperature of the catalyst prepared by pyrolysis is 500-1200 ℃, the reaction time is 1-5 h, and the heating rate is 1-10 ℃/min.

10. The method for preparing primary amine by catalyzing reductive amination of aldehyde, ketone and alcohol compounds according to claim 7, wherein in S2,

the reaction temperature is 50-200 ℃, the reaction time is 1-24 h, and the pressure in the reactor is 0.1-10 MPa.