A process for the catalytic synthesis of ethylamines from ethanol

Abstract

The application discloses a method for catalytically synthesizing ethylamine from ethanol, and belongs to the technical field of ethylamine synthesis. The method is used for solving the technical problems of low selectivity of a catalyst and low reaction efficiency of ethylamine in the prior art. The method comprises the following steps: adding deionized water and a composite auxiliary catalyst into a three-necked flask, stirring for 5-8 min at room temperature, adding a composite carrier into a reaction kettle, and immersing for 36-42 h at room temperature. A modified catalyst is obtained through post-treatment. The catalyst is modified. Through the cooperation of the composite auxiliary catalyst and the composite carrier, the active sites are divided, ethanol is aminated, the side reaction is inhibited, the reaction conversion rate, selectivity and stability are improved, the interference of impurities is removed, and the carbon deposition resistance of the reaction is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ethylamine synthesis, and particularly relates to a method for catalytically synthesizing ethylamine from ethanol. BACKGROUND

[0002] Ethylamine is a derivative of ammonia molecules with hydrogen atoms replaced by ethyl groups, mainly including monoethylamine, diethylamine, triethylamine, etc., and is an important fine chemical intermediate. Ethylamine can react with various compounds to form derivatives and is widely used in the pharmaceutical, pesticide, chemical additive 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 low-cost raw materials and green reaction path. Traditional preparation of ethylamine mainly relies on halogenated hydrocarbon amination or nitrile reduction, but there are problems such as high toxicity of raw materials and complex treatment of three wastes.

[0004] With the progress of catalytic technology, researchers have significantly improved the conversion efficiency of ethanol and the selectivity of amine products by designing new porous materials, regulating supported metal catalysts, and introducing photo / electro-catalysis strategies. However, there are still core challenges: first, the complex reaction path leads to high generation of by-products, increasing the cost of product separation; second, the catalyst is easily deactivated in continuous reaction, and the stability and life are difficult to meet the industrialization demand; third, the reaction conditions are harsh on equipment, further limiting the scale application.

[0005] The performance limitations of ethanol catalytic amination reaction are due to the mismatch between molecular level reaction kinetics and thermodynamics. In the amination process, ethanol needs to undergo dehydrogenation to form an intermediate acetaldehyde, then undergo nucleophilic addition with ammonia to form an imine intermediate, and finally be reduced by hydrogenation to form ethylamine.

[0006] However, the energy barrier for the dehydrogenation of ethanol to acetaldehyde is high, and the intermediate imine is chemically active and prone to side reactions, leading to a decrease in the selectivity of the target product. In addition, the active sites on the catalyst surface are insufficient for the synergistic catalysis of multi-step reactions. For example, strong adsorption of acetaldehyde on metal active centers may hinder the adsorption of ammonia molecules, while weak adsorption environment is not conducive to the directional construction of C-N bond.

[0007] Therefore, the industry is turning to the development of composite modified materials with high efficiency, selectivity, stability and anti-coking properties to break through the technical bottleneck of ethanol amination reaction. SUMMARY

[0008] The present application aims to provide a method for catalytically synthesizing ethylamine from ethanol, which solves the technical problems of low selectivity of the catalyst and low reaction efficiency of ethylamine in the prior art.

[0009] The object of the application can be achieved by the following technical scheme: a method for catalytically synthesizing ethylamine from ethanol, comprising the following steps:

[0010] S1, deionized water and a composite catalyst are added to a three-necked flask, stirred at room temperature for 5-8 min, then a composite carrier is added to the reactor, immersed at room temperature for 36-42 h, and a modified catalyst is obtained after post-treatment;

[0011] S2, vaporized ethanol and ammonia are introduced into the reactor containing the modified catalyst, the reactor temperature is 180-200 DEG C, the pressure is 1.5 MPa, and after dehydrogenation, amination and hydrogenation catalysis, a crude ethylamine is obtained;

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

[0013] The synthesis mechanism of the ethylamine is:

[0014] C2H5OH→C2H5O+H2

[0015] C2H5O+NH3→C2H4NH+H2O

[0016] C2H4NH+H2→C2H5NH2

[0017] The raw material ethanol and liquid ammonia are heated and vaporized by a vaporizer, converted from liquid to gas, and the gas is heated to the required initial reaction temperature, and in the presence of hydrogen, the ethanol is first dehydrogenated to form acetaldehyde, the hydrogen atom of acetaldehyde is replaced by an amino group to form ethylene amine, and the ethylene amine is an unstable intermediate product which is hydrogenated to form monoethylamine.

[0018] Further, in step S1, the amount ratio of the composite catalyst, the composite carrier and the deionized water is 2g:10g:50-80mL; the post-treatment comprises: after the reaction is completed, decanting, drying, calcining at a high temperature of 500-600 DEG C for 24 h, and then reacting in a reactor with hydrogen gas at a temperature of 300-400 DEG C for 4-5 h to obtain the modified catalyst; in step S2, the molar ratio of ethanol to ammonia is 1:6, and the liquid space velocity of ethanol is 0.8-1.2h -1 .

[0019] Further, in step S1, the composite carrier is obtained by the following steps:

[0020] A1, aluminum nitrate is dissolved in deionized water to prepare an aluminum nitrate solution with a concentration of 0.5-1.0 mol / L, cerium nitrate is added to the aluminum nitrate solution and stirred, and then cobalt nitrate is added to the mixture and stirred for 10 min to obtain a precursor solution;

[0021] A2, drop saturated ammonia water into the precursor solution to pH 8-10, temperature is kept at 60-80℃, aging 2-4h, post-processing to get composite carrier.

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

[0023] After the solution is mixed into a homogeneous phase, aluminum ions, cerium ions and cobalt ions freely diffuse in the solution. Under the addition of ammonia water, metal ion hydrolysis is triggered to generate hydroxide precipitate. Under alkaline conditions, the precipitate is formed by electrostatic adsorption and ion cluster aggregation to form ternary composite hydroxide. The composite hydroxide is partially dehydrated under the driving of thermodynamics to form hydroxyl oxide or amorphous oxide precursor. After further high-temperature dehydration and promotion of crystallization, a hierarchical pore structure is formed to obtain the 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-processing step is: after the reaction is completed, the filtrate is washed with deionized water until it is neutral. The filter cake is placed in an oven at 100-120℃ and dried to constant weight, then transferred to a muffle furnace in air atmosphere, heated to 500-800℃ at 5℃ / min, and calcined for 4-6 hours to obtain the composite carrier.

[0025] Further, in step S1, the processing step of the composite co-catalyst is:

[0026] B1, zinc nitrate, iron nitrate and deionized water are added to a beaker and stirred, ammonia water is added dropwise to adjust pH to 9-10, and the reaction is carried out for 2-3 hours to obtain layered double hydroxide;

[0027] B2, immerse the potassium nitrate solution into the layered double hydroxide system, immerse for 6-7 hours, and post-process to obtain the composite co-catalyst.

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

[0029] Metal ions diffuse freely in water to form a homogeneous solution, and the pH is adjusted by ammonia water to trigger the hydrolysis of metal ions to generate a precipitate, and the doping of potassium ions and the ion exchange with zinc ions and iron ions to form a solid solution, and the hydroxyl group of iron hydroxide and the hydroxyl group of zinc hydroxide form a hydrogen bond to promote the assembly of layered double hydroxide, and the potassium ion is embedded between the layers of the layered double hydroxide to balance the charge and stabilize the structure; with the dehydration of the hydroxyl oxide, the crystal form changes, the layered structure of the layered double hydroxide partially collapses at high temperature to form mesopores and micropores, and the iron oxide nanoparticles are dispersed on the surface of the zinc oxide to form a core-shell structure, thereby obtaining the composite catalyst.

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

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

[0032] Further, in step S2, the processing method of the vaporized ethanol and ammonia gas is to mix raw material ethanol and liquid ammonia after vaporization by a vaporizer.

[0033] The present application has the following advantages:

[0034] 1. The present application is a modification of the catalyst for the catalytic synthesis of ethylamine from ethanol, and a composite catalyst is used, the hydroxyl group of iron hydroxide and the hydroxyl group of zinc hydroxide are connected by hydrogen bonds to form a three-dimensional network structure, and the potassium ion stabilizes the layered double hydroxide structure through electrostatic interaction to prevent particle agglomeration during high-temperature calcination; zinc oxide adsorbs the iron ions entrained in the raw material ethanol to block the polymerization of acetaldehyde catalyzed by iron, the surface hydroxyl group of magnetite promotes the oxidation of acetaldehyde to acetic acid, reduces the generation of by-products, and reduces the residual amount of acetaldehyde, thereby improving the selectivity and purity of ethylamine; under the synergistic action of potassium oxide, zinc oxide and magnetite, potassium oxide provides alkaline dehydrogenation sites, zinc oxide blocks side reactions and adsorbs iron ions, and magnetite enhances stability and magnetic recovery, multi-level pores and surface hydroxyl groups promote mass transfer, crystal stability inhibits high-temperature sintering, reduces the amount of coking, and prolongs the service life of the catalyst.

[0035] 2、The application also modifies the carrier in the catalyst for catalytic synthesis of ethylamine from ethanol, and composites cobalt ions and cerium dioxide in the alumina carrier, wherein the oxygen vacancies of the cerium dioxide and the cobalt ions synergistically enhance the ethanol dehydrogenation rate, the acidic sites of the alumina promote the conversion of acetaldehyde into ethylamine, and the selectivity of ethylamine is improved; the symbiotic structure of CeO2-Al2O3 inhibits high-temperature sintering, the activity is maintained after 500 DEG C calcination, the stability of the catalyst is improved, cobalt dispersion optimizes the active sites, regulates the reaction path, improves the reaction conversion rate and selectivity, and the synergistic effect of cobalt ions and cerium dioxide blocks the condensation of acetaldehyde into tar, and reduces the coking amount.

[0036] 3、The application also modifies the carrier in the catalyst for catalytic synthesis of ethylamine from ethanol, and the composite catalyst and the composite carrier synergistically complete the path of converting ethanol into acetaldehyde to finally generate ethylamine, improve the dehydrogenation and amination rate, and remove interfering ions such as iron ions to block acetaldehyde polymerization and maintain efficient reaction. DETAILED DESCRIPTION

[0037] The technical solutions of the application will be described below in connection with the embodiments, obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0038] Embodiment 1

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

[0040] S1, preparation of composite catalyst

[0041] Take: zinc nitrate 99g, iron nitrate 67g and deionized water 1000ml are added to a beaker and stirred, ammonia water is added dropwise to adjust pH to 9, and reaction is carried out for 2 hours to obtain layered double hydroxide; 58.3g of potassium nitrate solution is immersed in the layered double hydroxide system for 6 hours, and after the reaction is completed, it is transferred to a 100 DEG C oven for drying for 6 hours, and then placed in a 500 DEG C muffle furnace for calcination for 3h to obtain a composite catalyst.

[0042] S2, preparation of composite carrier

[0043] Weighing: 188 g of aluminum nitrate is dissolved in 1000 mL of deionized water, 35 g of cerium nitrate is added to the aluminum nitrate solution under stirring, 15 g of cobalt nitrate is added to the mixed solution under stirring for 10 min to obtain a precursor solution; dropwise add ammonia water to the precursor solution until the pH is 8, the temperature is kept at 60℃, and the aging time is 2 h; after the reaction is completed, the filtrate is washed with deionized water until it is neutral; the filter cake is dried in an oven at 100℃ until the weight is constant, then transferred to a muffle furnace in an air atmosphere, heated to 500℃ at a rate of 5℃ / min, and calcined for 4 h to obtain a composite carrier.

[0044] S3, preparation of a modified catalyst

[0045] Weighing: 600 mL of deionized water and 20 g of a composite cocatalyst are added to a three-necked flask, stirred at room temperature for 5 min, then 100 g of a composite carrier is added to the reaction kettle, and immersed at room temperature for 36 h; after the reaction is completed, the filtrate is decanted and dried, and then calcined at 500℃ for 24 h; then the modified catalyst is obtained by reacting in a reactor with hydrogen gas at a temperature of 300℃ for 4 h.

[0046] S4, preparation of ethylamine

[0047] The vaporized ethanol and ammonia gas are introduced into the reactor containing the modified catalyst, the reactor temperature is 180℃, the pressure is 1.5 MPa, and the reaction time is 8 h to obtain a crude ethylamine product;

[0048] Saturated hydrochloric acid is added to the crude ethylamine product, the pH is adjusted to 6, stirred for 10 min, and then allowed to stand; the aqueous phase is separated, activated carbon is added to the aqueous phase for adsorption and decolorization, then saturated sodium hydroxide is added to adjust the pH to 10, followed by static adsorption with 3A molecular sieves, and finally the crude ethylamine product is distilled at 50℃ under reduced pressure to obtain ethylamine.

[0049] Example 2

[0050] The present embodiment provides a method for catalytically synthesizing ethylamine from ethanol, comprising the following steps:

[0051] S1, preparation of a composite cocatalyst

[0052] Weighing: 99 g of zinc nitrate, 67 g of iron nitrate, and 1000 mL of deionized water are added to a beaker and stirred, ammonia water is added dropwise to adjust the pH to 9, and the reaction is carried out for 2.5 hours to obtain a layered double hydroxide; 58.3 g of potassium nitrate solution is immersed in the layered double hydroxide system for 7 hours, and then transferred to a 100℃ oven for drying for 6 hours, and then placed in a 550℃ muffle furnace for calcination for 4 h to obtain a composite cocatalyst.

[0053] S2, preparation of a composite carrier

[0054] Weighing: 188 g of aluminum nitrate is dissolved in 1000 mL of deionized water, 35 g of cerium nitrate is added to the aluminum nitrate solution under stirring, 15 g of cobalt nitrate is added to the mixed solution under stirring for 10 min to obtain a precursor solution; ammonia water is added dropwise to the precursor solution until the pH is 8, the temperature is kept at 70℃, and the solution is aged for 3 h; after the reaction is completed, the filtrate is washed with deionized water until it is neutral; the filter cake is dried in an oven at 100℃ until the weight is constant, and then transferred to a muffle furnace in an air atmosphere, heated to 550℃ at a rate of 5℃ / min, and calcined for 5 h to obtain a composite carrier.

[0055] S3, preparation of a modified catalyst

[0056] Weighing: 600 mL of deionized water and 20 g of a composite promoter are added to a three-necked flask, stirred at room temperature for 7 min, and then 100 g of a composite carrier is added to the reaction kettle and immersed at room temperature for 39 h; after the reaction is completed, the solution is decanted and dried, and then calcined at 550℃ for 24 h; the modified catalyst is obtained by reacting in a reactor with hydrogen at a temperature of 300℃ for 4 h.

[0057] S4, preparation of ethylamine

[0058] The vaporized ethanol and ammonia gas are introduced into the reactor containing the modified catalyst, the reactor temperature is 180-200℃, the pressure is 1.5 MPa, and the reaction is carried out for 9 h to obtain a crude ethylamine product;

[0059] Saturated hydrochloric acid is added to the crude ethylamine product to adjust the pH to 6, stirred for 10 min, and then allowed to stand; the aqueous phase is separated, activated carbon is added to the aqueous phase to adsorb and decolorize, and then saturated sodium hydroxide is added to adjust the pH to 10; the crude ethylamine product is finally distilled at 50℃ under reduced pressure to obtain ethylamine.

[0060] Example 3

[0061] The present embodiment provides a method for catalytically synthesizing ethylamine from ethanol, comprising the following steps:

[0062] S1, preparation of a composite promoter

[0063] Weighing: 99 g of zinc nitrate, 67 g of iron nitrate, and 1000 mL of deionized water are added to a beaker and stirred; ammonia water is added dropwise to adjust the pH to 10, and the reaction is carried out for 3 h to obtain a layered double hydroxide; 58.3 g of a potassium nitrate solution is immersed in the layered double hydroxide system for 7 h; after the reaction is completed, the solution is transferred to a 100℃ oven and dried for 8 h, and then placed in a 600℃ muffle furnace and calcined for 5 h to obtain a composite promoter.

[0064] S2, preparation of a composite carrier

[0065] Weighing: 188 g of aluminum nitrate is dissolved in 1000 mL of deionized water, 35 g of cerium nitrate is added to the aluminum nitrate solution under stirring, 15 g of cobalt nitrate is added to the mixture under stirring for 10 min to obtain a precursor solution; ammonia water is added dropwise to the precursor solution until the pH is 10, the temperature is kept at 80℃, and the aging time is 4 h; after the reaction is completed, the filtrate is washed with deionized water until it is neutral; the filter cake is dried in an oven at 100℃ until the weight is constant, and then transferred to a muffle furnace in an air atmosphere, heated to 600℃ at a rate of 5℃ / min, and calcined for 6 h to obtain a composite carrier.

[0066] S3, preparation of a modified catalyst

[0067] Weighing: 600 mL of deionized water and 20 g of a composite promoter are added to a three-necked flask, stirred at room temperature for 8 min, and then 100 g of a composite carrier is added to the reaction kettle for 42 h of immersion at room temperature; after the reaction is completed, the product is decanted and dried, and then calcined at a high temperature of 500℃ for 24 h; the modified catalyst is obtained by reacting in a reactor with hydrogen gas at a temperature of 300℃ for 4 h.

[0068] S4, preparation of ethylamine

[0069] The vaporized ethanol and ammonia gas are introduced into the reactor containing the modified catalyst, the reactor temperature is 200℃, the pressure is 1.5 MPa, and the reaction time is 10 h to obtain a crude ethylamine product;

[0070] Saturated hydrochloric acid is added to the crude ethylamine product to adjust the pH to 6, stirred for 10 min, and then allowed to stand; the aqueous phase is separated, activated carbon is added to the aqueous phase for adsorption and decolorization, and then saturated sodium hydroxide is used to adjust the pH to 10; 3A molecular sieves are used for static adsorption, and finally the crude ethylamine product is distilled at 50℃ under reduced pressure 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 instead of the composite promoter in step S1.

[0073] Comparative Example 2

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

[0075] Comparative Example 3

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

[0077] Comparative Example 4

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

[0079] Performance test:

[0080] According to the formula , the conversion rate of catalytic synthesis of ethylamine from ethanol is tested, wherein 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 catalytic synthesis of ethylamine from ethanol is tested, wherein n1 is the amount of substance of the yield of ethylamine, n 总 is the amount of substance of the crude ethylamine.

[0082] According to the formula , the purity of ethylamine in the catalytic synthesis of ethylamine from ethanol is tested, wherein m1 is the mass of ethylamine, and m 总 is the mass of the crude ethylamine.

[0083] The anti-coking property of the modified catalyst prepared in Examples 1-3 and Comparative Examples 1-4 is determined according to the standard GB / T 26930.8-2014 “Carbon Materials for Primary Aluminum Production Coal Tar Pitch Part 8: Determination of Coking Value”;

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

[0085] Table 1-Performance test data table of samples

[0086]

[0087] Data analysis:

[0088] Comparative analysis of the data in Table 1 above, the catalytic synthesis of ethylamine from ethanol is modified by the catalyst, the reaction conversion rate reaches 96.8%, the selectivity of the catalyst reaches 88%, the purity of the product ethylamine reaches 89%, the coking amount reaches 4.6%, the total mass loss of the thermal stability reaches 4.1%, and the mechanical stability is not turbid, which shows that the catalyst is modified, the composite catalyst and the composite carrier are synergized, the active sites are divided, the ethanol is aminated, the side reaction is inhibited, the reaction conversion rate, the selectivity and the stability are improved, the interference of impurities is removed, and the anti-coking property of the reaction is improved.

[0089] Comparative Example 1 and Example, the hydroxyl group of Fe(OH)3 and the hydroxyl group of Zn(OH)2 form hydrogen bond, promote the assembly of layered double hydroxide, potassium ion is embedded in the interlayer of layered double hydroxide, balance the charge and stabilize the structure, improve the stability and anti-coking property;

[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, decant, dry, calcine at 500-600℃ for 24 hours, and then react in a reactor with hydrogen gas introduced at 300-400℃ for 4-5 hours 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. Ethylamine crude product is obtained by acid-base neutralization, dehydration, adsorption, vacuum distillation and drying; 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, wash the filtrate with deionized water several times until it is neutral, place the filter cake in an oven at 100-120℃ to dry to constant weight, then transfer it to a muffle furnace in an air atmosphere, heat it at 5℃ / min to 500-800℃, and calcine for 4-6 hours to obtain the composite carrier; 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, transfer to an oven at 100°C to dry for 6-8 hours, and then calcine in a muffle furnace at 500-600°C for 3-5 hours to obtain the composite co-catalyst.

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; 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 A1, the aluminum nitrate is Al(NO3)3·9H2O, the cerium nitrate is Ce(NO3)3·6H2O, 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.

4. The method for catalytic synthesis of ethylamine from ethanol according to claim 1, 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.

5. The method for catalytic synthesis of ethylamine from ethanol according to claim 1, characterized in that, In step B2, the concentration of the potassium nitrate solution is 5 wt%.

6. 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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