Method for catalytically synthesizing ethylamine from ethanol

Abstract

The invention discloses a method for catalytically synthesizing ethyl amine from ethanol, belongs to the technical field of ethyl amine synthesis, and aims to solve the technical problems of low catalyst selectivity and low reaction efficiency of ethyl amine in the process of catalytically synthesizing ethyl amine from ethanol in the prior art. The preparation method comprises the following steps: adding deionized water and a composite cocatalyst into a three-neck flask, stirring for 5-8 minutes at room temperature, adding a composite carrier into a reaction kettle, dipping for 36-42 hours at room temperature, and performing post-treatment to obtain the modified catalyst. According to the invention, the catalyst is modified, and under the synergistic effect of the composite promoter and the composite carrier, through division of active sites, ethanol is aminated, side reactions are inhibited, the reaction conversion rate, selectivity and stability are improved, the interference of impurities is eliminated, and the carbon deposition resistance of the reaction is improved.

Description

Technical Field

[0001] This invention relates to the field of ethylamine synthesis technology, and more specifically to a method for the catalytic synthesis of ethylamine from ethanol. Background Technology

[0002] Ethylamine is a derivative formed by replacing the hydrogen atom of an ammonia molecule with an ethyl group. It mainly includes monoethylamine, diethylamine, triethylamine, etc. It is an important fine chemical intermediate that can react with a variety of compounds to form derivatives. It is widely used in pharmaceuticals, pesticides, chemical auxiliaries, and military industries.

[0003] In recent years, the catalytic synthesis of ethylamine from ethanol has become a research hotspot in the field of fine chemicals due to its advantages such as cheap and readily available raw materials and green reaction routes. Traditional ethylamine preparation mainly relies on the ammonolysis of halogenated hydrocarbons or the reduction of nitriles, but there are problems such as high toxicity of raw materials and complex treatment of waste.

[0004] With advancements in catalysis technology, researchers have significantly improved ethanol conversion efficiency and amine product selectivity through strategies such as designing novel porous materials, regulating supported metal catalysts, and introducing photo / electrocatalysis. However, core challenges remain: First, complex reaction pathways lead to high byproduct formation and increased product separation costs; second, catalysts are prone to deactivation in continuous reactions, and their stability and lifespan are difficult to meet industrial requirements; and third, the stringent reaction conditions place stringent demands on equipment, further limiting large-scale applications.

[0005] The performance limitations of ethanol-catalyzed amination reactions stem from the mismatch between molecular-level reaction kinetics and thermodynamics. During amination, ethanol must undergo dehydrogenation to generate acetaldehyde intermediate, then undergo nucleophilic addition with ammonia to form an imine intermediate, and finally be reduced by hydrogenation to generate ethylamine.

[0006] However, the energy barrier for the dehydrogenation of ethanol to acetaldehyde is relatively high, and the intermediate imine is chemically reactive and prone to side reactions, leading to a decrease in the selectivity of the target product. In addition, the synergistic catalytic ability of the active sites on the catalyst surface for multi-step reactions is insufficient. For example, the excessive adsorption of acetaldehyde by the metal active center may hinder the adsorption of ammonia molecules, while a weak adsorption environment is not conducive to the directional construction of CN bonds.

[0007] Therefore, the industry is turning to the development of catalytic systems with high efficiency, selectivity, stability, and resistance to carbon deposition through composite modified materials in order to overcome the technical bottleneck of ethanol amination reaction. Summary of the Invention

[0008] The purpose of this invention is to provide a method for the catalytic synthesis of ethylamine from ethanol, which solves the technical problems of low catalyst selectivity and low reaction efficiency of ethylamine in the catalytic synthesis of ethylamine from ethanol in the prior art.

[0009] The objective of this invention can be achieved through the following technical solution: a method for the catalytic synthesis of ethylamine from ethanol, comprising the following steps:

[0010] S1. Add deionized water and composite co-catalyst to a three-necked flask, stir at room temperature for 5-8 minutes, then add composite support to the reactor, impregnate at room temperature for 36-42 hours, and then perform post-treatment to obtain the modified catalyst.

[0011] S2. The vaporized ethanol and ammonia are passed into a reactor containing a modified catalyst. The reactor temperature is 180-200℃ and the pressure is 1.5MPa. After dehydrogenation, amination and hydrogenation catalysis, crude ethylamine is obtained.

[0012] S3. Crude ethylamine is obtained by acid-base neutralization, dehydration, adsorption, vacuum distillation and drying.

[0013] The synthesis mechanism of the ethylamine is as follows:

[0014] C2H5OH→C2H5O+H2

[0015] C2H5O + NH3 → C2H4NH + H2O

[0016] C2H4NH + H2 → C2H5NH2

[0017] The raw materials ethanol and liquid ammonia are heated and vaporized in a vaporizer, changing from liquid to gas. The gas is then heated again to the required initial reaction temperature. In the presence of hydrogen, and catalyzed by a catalyst, based on the difference in the activity of free radicals in the molecular structure, ethanol first undergoes dehydrogenation to produce acetaldehyde. The hydrogen atoms of acetaldehyde are replaced by amino groups to produce ethylenediamine. Ethylenediamine is an unstable intermediate product, which is then hydrogenated to produce monoethylamine.

[0018] Further, in step S1, the ratio of the composite co-catalyst, composite support, and deionized water is 2g:10g:50-80mL; the post-treatment includes: after the reaction is complete, decantation, drying, calcination at 500-600℃ for 24h, and then reaction in a reactor with hydrogen gas introduced at 300-400℃ for 4-5h to obtain the modified catalyst; in step S2, the molar ratio of ethanol to ammonia is 1:6, and the ethanol liquid hourly space velocity is 0.8-1.2h. -1 .

[0019] Furthermore, in step S1, the composite carrier is obtained through the following steps:

[0020] A1. Dissolve aluminum nitrate in deionized water to prepare an aluminum nitrate solution of 0.5-1.0 mol / L. Add cerium nitrate to the aluminum nitrate solution and stir. Then add cobalt nitrate to the mixture and stir for 10 min to obtain the precursor solution.

[0021] A2. Add saturated ammonia to the precursor solution until the pH is 8-10, maintain the temperature at 60-80℃, age for 2-4 hours, and then process to obtain the composite carrier.

[0022] The synthesis mechanism of the composite carrier is as follows:

[0023] After the solution is mixed to form a homogeneous phase, aluminum ions, cerium ions, and cobalt ions diffuse freely in the solution. With the addition of ammonia, the metal ions are triggered to hydrolyze and form hydroxide precipitates. Under alkaline conditions, the precipitates are formed by electrostatic adsorption and ion cluster aggregation, forming ternary composite hydroxides. The composite hydroxides are partially dehydrated under thermodynamic drive to form hydroxyl oxides or amorphous oxide precursors. After further high-temperature dehydration and crystallization, a multi-level porous structure is formed, resulting in a composite carrier.

[0024] Further, in step A1, the aluminum nitrate is Al(NO3)3·9H2O, the cerium nitrate is Ce(NO3)3·6H2O, and the cobalt nitrate is Co(NO3)2·6H2O. The molar ratio of aluminum nitrate, cerium nitrate, and cobalt nitrate is 3:1:0.3, and the stirring speed is 400-600 rpm. In step A2, the post-treatment step is as follows: after the reaction is completed, the filtrate is washed multiple times with deionized water until it is neutral. The filter cake is placed in an oven at 100-120℃ and dried to constant weight. Then it is transferred to a muffle furnace in an air atmosphere and heated to 500-800℃ at 5℃ / min for 4-6 hours to obtain the composite carrier.

[0025] Furthermore, in step S1, the processing steps of the composite co-catalyst are as follows:

[0026] B1. Add zinc nitrate, ferric nitrate and deionized water to a beaker and stir. Add ammonia dropwise to adjust the pH to 9-10. React for 2-3 hours to obtain layered double hydroxides.

[0027] B2. Impregnate the layered double hydroxide system with potassium nitrate solution for 6-7 hours, and then perform post-treatment to obtain the composite co-catalyst.

[0028] The synthesis mechanism of the composite co-catalyst is as follows:

[0029] Metal ions diffuse freely in water to form a homogeneous solution. Adjusting the pH with ammonia triggers the hydrolysis of metal ions to form a precipitate. Potassium ions doping undergo ion exchange with zinc and iron ions to form a solid solution. Furthermore, the hydroxyl groups of iron hydroxide and zinc hydroxide form hydrogen bonds, promoting the assembly of layered double hydroxides. Potassium ions are embedded in the interlayer of the layered double hydroxides to balance the charge and stabilize the structure. As the hydroxyl oxides dehydrate, the crystal form changes, and the layered structure of the layered double hydroxides partially collapses at high temperatures, forming mesopores and micropores. Ferric oxide nanoparticles are dispersed on the surface of zinc oxide to form a core-shell structure, thus obtaining a composite cocatalyst.

[0030] Furthermore, in step B1, the zinc nitrate is Zn(NO3)2·6H2O and the ferric nitrate is Fe(NO3)3·9H2O, the molar ratio of zinc nitrate to ferric nitrate is 2:1, and the concentration of the mixed solution is 0.5 mol / L.

[0031] Furthermore, in step B2, the concentration of the potassium nitrate solution is 5 wt%; the post-treatment includes: after the reaction is completed, transferring it to a 100°C oven for drying for 6-8 hours, and then placing it in a muffle furnace at 500-600°C for calcination for 3-5 hours to obtain the composite co-catalyst.

[0032] Furthermore, in step S2, the processing method for the vaporized ethanol and ammonia is to obtain the raw material ethanol and liquid ammonia by vaporizing and mixing them in a vaporizer.

[0033] The present invention has the following beneficial effects:

[0034] 1. This invention modifies the catalyst for the ethanol-catalyzed synthesis of ethylamine by using a composite co-catalyst. The hydroxyl groups of iron hydroxide and zinc hydroxide are linked by hydrogen bonds to form a three-dimensional network structure. Potassium ions stabilize the layered double hydroxide structure through electrostatic interaction, preventing particle agglomeration during high-temperature calcination. Zinc oxide adsorbs iron ions carried in the raw ethanol, blocking the iron-catalyzed polymerization of acetaldehyde. The hydroxyl groups on the surface of iron oxide promote the oxidation of acetaldehyde to acetic acid, reducing the generation of by-products and lowering the residual amount of acetaldehyde, thereby improving the selectivity and purity of ethylamine. Under the synergistic effect of potassium oxide, zinc oxide, and iron oxide, potassium oxide provides alkaline dehydrogenation sites, zinc oxide blocks side reactions and adsorbs iron ions, iron oxide enhances stability and magnetic recovery, multi-level channels and surface hydroxyl groups promote mass transfer, crystal stability inhibits high-temperature sintering, reduces coking, and extends catalyst life.

[0035] 2. This invention also modifies the support in the catalyst for the catalytic synthesis of ethylamine from ethanol by combining cobalt ions and cerium dioxide in an alumina support. The oxygen vacancies of cerium dioxide and cobalt ions synergistically enhance the ethanol dehydrogenation rate, while the acidic sites of alumina promote the conversion of acetaldehyde to ethylamine, thus improving the selectivity of ethylamine. The symbiotic structure of CeO2-Al2O3 inhibits high-temperature sintering, and the activity is maintained after calcination at 500℃, improving the stability of the catalyst. Cobalt dispersion optimizes the active sites, regulates the reaction pathway, and improves the reaction conversion rate and selectivity. The synergistic effect of cobalt ions and cerium dioxide blocks the condensation of acetaldehyde into tar, reducing the amount of coking.

[0036] 3. This invention also modifies the support in the catalyst for the catalytic synthesis of ethylamine from ethanol. The composite co-catalyst and the composite support work synergistically to efficiently complete the pathway of ethanol to acetaldehyde and finally to ethylamine, improve the dehydrogenation and amination rates, remove interfering ions such as iron ions, block acetaldehyde polymerization, and maintain the high efficiency of the reaction. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] This embodiment provides a method for the catalytic synthesis of ethylamine from ethanol, including the following steps:

[0040] S1. Preparation of composite cocatalysts

[0041] Weigh out 99g of zinc nitrate, 67g of ferric nitrate, and 1000mL of deionized water and add them to a beaker. Stir and add ammonia dropwise to adjust the pH to 9. React for 2 hours to obtain a layered double hydroxide. Immerse 58.3g of potassium nitrate solution into the layered double hydroxide system for 6 hours. After the reaction is complete, transfer it to a 100℃ oven to dry for 6 hours, and then place it in a muffle furnace at 500℃ for 3 hours to calcine to obtain a composite co-catalyst.

[0042] S2. Preparation of composite carrier

[0043] Weigh out 188g of aluminum nitrate and dissolve it in 1000mL of deionized water. Add 35g of cerium nitrate to the aluminum nitrate solution and stir. Then add 15g of cobalt nitrate to the mixture and stir for 10min to obtain a precursor solution. Add ammonia dropwise to the precursor solution until the pH is 8. Maintain the temperature at 60℃ and age for 2h. After the reaction is complete, wash the filtrate several times with deionized water until it is neutral. Place the filter cake in a 100℃ oven to dry to constant weight. Then transfer it to a muffle furnace in an air atmosphere and calcine it at 500℃ at a rate of 5℃ / min for 4 hours to obtain a composite carrier.

[0044] S3. Preparation of modified catalysts

[0045] Weigh 600 mL of deionized water and 20 g of composite co-catalyst into a three-necked flask, stir at room temperature for 5 min, then add 100 g of composite support to the reactor, impregnate at room temperature for 36 h, after the reaction is complete, decant and dry, calcine at 500℃ for 24 h, and then react in a reactor with hydrogen gas introduced at 300℃ for 4 h to obtain the modified catalyst.

[0046] S4. Preparation of ethylamine

[0047] The vaporized ethanol and ammonia were passed into a reactor containing a modified catalyst. The reactor temperature was 180℃ and the pressure was 1.5MPa. The reaction was carried out for 8 hours to obtain crude ethylamine.

[0048] Saturated hydrochloric acid was added to crude ethylamine to adjust the pH to 6. The mixture was stirred for 10 minutes, allowed to stand, and the aqueous phase was separated. Activated carbon was added to the aqueous phase for adsorption and decolorization. The pH was then adjusted to 10 with saturated sodium hydroxide. Subsequently, static adsorption was performed using 3A molecular sieves. Finally, the crude ethylamine was distilled under reduced pressure at 50°C to obtain ethylamine.

[0049] Example 2

[0050] This embodiment provides a method for the catalytic synthesis of ethylamine from ethanol, including the following steps:

[0051] S1. Preparation of composite cocatalysts

[0052] Weigh out 99g of zinc nitrate, 67g of ferric nitrate, and 1000mL of deionized water and add them to a beaker. Stir and add ammonia dropwise to adjust the pH to 9. React for 2.5 hours to obtain a layered double hydroxide. Immerse 58.3g of potassium nitrate solution into the layered double hydroxide system for 7 hours. After the reaction is complete, transfer it to a 100℃ oven to dry for 6 hours, and then place it in a muffle furnace at 550℃ for 4 hours to calcine to obtain a composite co-catalyst.

[0053] S2. Preparation of composite carrier

[0054] Weigh out 188g of aluminum nitrate and dissolve it in 1000mL of deionized water. Add 35g of cerium nitrate to the aluminum nitrate solution and stir. Then add 15g of cobalt nitrate to the mixture and stir for 10min to obtain a precursor solution. Add ammonia dropwise to the precursor solution until the pH is 8. Maintain the temperature at 70℃ and age for 3h. After the reaction is complete, wash the filtrate several times with deionized water until it is neutral. Place the filter cake in a 100℃ oven to dry to constant weight. Then transfer it to a muffle furnace in an air atmosphere and calcine it at 550℃ at a rate of 5℃ / min for 5 hours to obtain a composite carrier.

[0055] S3. Preparation of modified catalysts

[0056] Weigh 600 mL of deionized water and 20 g of composite co-catalyst into a three-necked flask, stir at room temperature for 7 min, then add 100 g of composite support to the reactor, impregnate at room temperature for 39 h, after the reaction is complete, decant, dry, calcine at 550 °C for 24 h, and then react in a reactor with hydrogen gas introduced at 300 °C for 4 h to obtain the modified catalyst.

[0057] S4. Preparation of ethylamine

[0058] The vaporized ethanol and ammonia were passed into a reactor containing a modified catalyst. The reactor temperature was 180-200℃ and the pressure was 1.5MPa. The reaction was carried out for 9 hours to obtain crude ethylamine.

[0059] Saturated hydrochloric acid was added to crude ethylamine to adjust the pH to 6. The mixture was stirred for 10 minutes, allowed to stand, and the aqueous phase was separated. Activated carbon was added to the aqueous phase for adsorption and decolorization. The pH was then adjusted to 10 with saturated sodium hydroxide. Subsequently, static adsorption was performed using 3A molecular sieves. Finally, the crude ethylamine was distilled under reduced pressure at 50°C to obtain ethylamine.

[0060] Example 3

[0061] This embodiment provides a method for the catalytic synthesis of ethylamine from ethanol, including the following steps:

[0062] S1. Preparation of composite cocatalysts

[0063] Weigh out 99g of zinc nitrate, 67g of ferric nitrate, and 1000mL of deionized water and add them to a beaker. Stir and add ammonia dropwise to adjust the pH to 10. React for 3 hours to obtain a layered double hydroxide. Immerse 58.3g of potassium nitrate solution into the layered double hydroxide system for 7 hours. After the reaction is complete, transfer it to a 100℃ oven to dry for 8 hours, and then place it in a muffle furnace at 600℃ for 5 hours to calcine to obtain a composite co-catalyst.

[0064] S2. Preparation of composite carrier

[0065] Weigh out 188g of aluminum nitrate and dissolve it in 1000mL of deionized water. Add 35g of cerium nitrate to the aluminum nitrate solution and stir. Then add 15g of cobalt nitrate to the mixture and stir for 10min to obtain a precursor solution. Add ammonia dropwise to the precursor solution until the pH is 10. Maintain the temperature at 80℃ and age for 4h. After the reaction is complete, wash the filtrate several times with deionized water until it is neutral. Place the filter cake in a 100℃ oven to dry to constant weight. Then transfer it to a muffle furnace in an air atmosphere and calcine it at 600℃ at a rate of 5℃ / min for 6 hours to obtain a composite carrier.

[0066] S3, Preparation of modified catalysts

[0067] Weigh 600 mL of deionized water and 20 g of composite co-catalyst into a three-necked flask, stir at room temperature for 8 min, then add 100 g of composite support to the reactor, impregnate at room temperature for 42 h, after the reaction is complete, decant, dry, calcine at 500℃ for 24 h, and then react in a reactor with hydrogen gas introduced at 300℃ for 4 h to obtain the modified catalyst.

[0068] S4. Preparation of ethylamine

[0069] The vaporized ethanol and ammonia were passed into a reactor containing a modified catalyst. The reactor temperature was 200℃ and the pressure was 1.5MPa. The reaction was carried out for 10 hours to obtain crude ethylamine.

[0070] Saturated hydrochloric acid was added to crude ethylamine to adjust the pH to 6. The mixture was stirred for 10 minutes, allowed to stand, and the aqueous phase was separated. Activated carbon was added to the aqueous phase for adsorption and decolorization. The pH was then adjusted to 10 with saturated sodium hydroxide. Subsequently, static adsorption was performed using 3A molecular sieves. Finally, the crude ethylamine was distilled under reduced pressure at 50°C to obtain ethylamine.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 3 is that step S1 is omitted, and K2O is used to replace the composite cocatalyst in step S1.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 3 is that cerium nitrate was not added in step S2.

[0075] Comparative Example 3

[0076] The difference between this comparative example and Example 3 is that in step S2, alumina is used instead of the composite carrier.

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 3 is that the cobalt content in step S2 is replaced with 6 wt%.

[0079] Performance testing:

[0080] According to the formula The conversion rate of ethanol to ethylamine was tested. In the formula, m1 is the actual yield of ethylamine, M1 is the relative molecular mass of ethylamine, m0 is the mass of ethanol, and M0 is the relative molecular mass of ethanol.

[0081] According to the formula The selectivity of ethanol-catalyzed synthesis of ethylamine was tested, where n1 is the molar amount of ethylamine produced, and n... 总 This represents the amount of crude ethylamine.

[0082] According to the formula The purity of ethylamine in the ethanol-catalyzed synthesis of ethylamine was tested, where m1 is the mass of ethylamine, and m 总 This refers to the mass of crude ethylamine.

[0083] The anti-coking properties of the modified catalysts prepared in Examples 1-3 and Comparative Examples 1-4 were determined in accordance with the standard GB / T 26930.8-2014 "Coal tar pitch for primary aluminum production - Part 8: Determination of coking value".

[0084] The thermal stability of the modified catalysts prepared in Examples 1-3 and Comparative Examples 1-4 was determined according to standard NB / SH / T 0859-2013 "Determination of Thermal Stability of Chemical Substances - Thermal Analysis Method". The specific test results are shown in Table 1 below:

[0085] Table 1 - Performance Test Data of Samples

[0086]

[0087] Data Analysis:

[0088] Comparative analysis of the data in Table 1 above shows that the ethanol-catalyzed synthesis of ethylamine in this invention involves catalyst modification. The reaction conversion rate reached 96.8%, the catalyst selectivity reached 88%, the purity of the ethylamine product reached 89%, the coking amount reached 4.6%, the total mass loss of thermal stability reached 4.1%, and the mechanical stability was not turbid. This indicates that catalyst modification, under the synergistic effect of composite cocatalyst and composite support, through the division of labor of active sites, enables ethanol amination, inhibits side reactions, improves reaction conversion rate, selectivity and stability, removes interference from impurities, and improves the reaction's resistance to carbon deposition.

[0089] Compared with the examples, in Comparative Example 1, the hydroxyl groups of Fe(OH)3 and Zn(OH)2 form hydrogen bonds, which promotes the assembly of layered double hydroxides. Potassium ions are embedded in the interlayer of the layered double hydroxides, balancing the charge and stabilizing the structure, thereby improving stability and resistance to carbon deposition.

[0090] Compared with the examples, in Comparative Example 2, the CeO2 composite in the Al2O3 support, the oxygen vacancies of CeO2 and cobalt ions synergistically enhance the ethanol dehydrogenation rate, and the acidic sites of Al2O3 promote the conversion of acetaldehyde to ethylamine, thereby improving the selectivity of ethylamine.

[0091] Compared with the examples, the ternary composite hydroxide partially dehydrates under thermodynamic drive to form hydroxyl oxide or amorphous oxide precursors. After further high-temperature dehydration and crystallization, a hierarchical porous structure is formed, which improves the conversion rate, selectivity and stability of the reaction.

[0092] Compared with the examples, Comparative Example 4 shows that the number of active sites of cobalt is increased, which improves the reaction conversion rate. However, excessive cobalt ions are prone to forming CoO(OH) nanoparticles, which leads to the coverage of active sites. In addition, excessive cobalt will catalyze the condensation of propyl acetate to generate tar, increasing the amount of coking.

[0093] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for the catalytic synthesis of ethylamine from ethanol, characterized in that, Includes the following steps: S1. Add deionized water and composite co-catalyst to a three-necked flask, stir at room temperature for 5-8 minutes, then add composite support to the reactor, impregnate at room temperature for 36-42 hours, and then perform post-treatment to obtain the modified catalyst. S2. The vaporized ethanol and ammonia are passed into a reactor containing a modified catalyst. The reactor temperature is 180-200℃ and the pressure is 1.5MPa. Hydrogenation catalysis is carried out for 8-10 hours to obtain crude ethylamine. S3. Crude ethylamine is obtained by acid-base neutralization, dehydration, adsorption, vacuum distillation and drying.

2. The method for catalytic synthesis of ethylamine from ethanol according to claim 1, characterized in that, In step S1, the ratio of the composite co-catalyst, composite support, and deionized water is 2g:10g:50-80mL; the post-treatment includes: after the reaction is complete, decantation, drying, calcination at 500-600℃ for 24h, and then reaction in a reactor with hydrogen gas introduced at 300-400℃ for 4-5h to obtain the modified catalyst; in step S2, the molar ratio of ethanol to ammonia is 1:6, and the ethanol liquid hourly space velocity is 0.8-1.2h. -1 .

3. The method for catalytic synthesis of ethylamine from ethanol according to claim 1, characterized in that, In step S1, the composite carrier is obtained through the following steps: A1. Dissolve aluminum nitrate in deionized water to prepare an aluminum nitrate solution of 0.5-1.0 mol / L. Add cerium nitrate to the aluminum nitrate solution and stir. Then add cobalt nitrate to the mixture and stir for 10 min to obtain the precursor solution. A2. Add saturated ammonia to the precursor solution until the pH is 8-10, maintain the temperature at 60-80℃, age for 2-4 hours, and then process to obtain the composite carrier.

4. The method for catalytic synthesis of ethylamine from ethanol according to claim 3, characterized in that, In step A1, the aluminum nitrate is Al(NO3)3·9H2O, the cerium nitrate is Ce(NO3)3·6H2O, and the cobalt nitrate is Co(NO3)2·6H2O. The molar ratio of aluminum nitrate, cerium nitrate, and cobalt nitrate is 3:1:0.3, and the stirring speed is 400-600 rpm. In step A2, the post-treatment step is as follows: after the reaction is completed, the filtrate is washed multiple times with deionized water until it is neutral. The filter cake is placed in an oven at 100-120℃ and dried to constant weight. Then it is transferred to a muffle furnace in an air atmosphere and heated to 500-800℃ at 5℃ / min for 4-6 hours to obtain the composite carrier.

5. The method for catalytic synthesis of ethylamine from ethanol according to claim 1, characterized in that, In step S1, the processing steps of the composite co-catalyst are as follows: B1. Add zinc nitrate, ferric nitrate and deionized water to a beaker and stir. Add ammonia dropwise to adjust the pH to 9-10. React for 2-3 hours to obtain layered double hydroxides. B2. Impregnate the layered double hydroxide system with potassium nitrate solution for 6-7 hours, and then perform post-treatment to obtain the composite co-catalyst.

6. The method for catalytic synthesis of ethylamine from ethanol according to claim 5, characterized in that, In step B1, the zinc nitrate is Zn(NO3)2·6H2O and the ferric nitrate is Fe(NO3)3·9H2O, the molar ratio of zinc nitrate to ferric nitrate is 2:1, and the concentration of the mixed solution is 0.5 mol / L.

7. The method for catalytic synthesis of ethylamine from ethanol according to claim 5, characterized in that, In step B2, the concentration of the potassium nitrate solution is 5 wt%; the post-treatment includes: after the reaction is completed, transferring it to a 100°C oven to dry for 6-8 hours, and then placing it in a muffle furnace at 500-600°C for 3-5 hours to calcine, thereby obtaining the composite co-catalyst.

8. The method for catalytic synthesis of ethylamine from ethanol according to claim 1, characterized in that, In step S2, the processing method for the vaporized ethanol and ammonia is to vaporize and mix the raw material ethanol and liquid ammonia in a vaporizer.

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