A process for the preparation of ethylenediamine

Abstract

The application discloses a method for preparing ethylenediamine. The method comprises the following steps: loading ethanolamine into a reaction kettle loaded with a catalyst, sequentially introducing ammonia and hydrogen into the reaction kettle, and reacting at 170 DEG C to 210 DEG C for 10 to 18 hours to generate ethylenediamine through a catalytic amination reaction; the catalyst is a core-shell structure, and is composed of a silica-aluminum oxide composite shell and a metal core; the metal core is metal M1 and metal M2, which are Ni and Cu respectively; the total molar amount of Ni and Cu accounts for 67 to 91% of the whole catalyst, and the molar ratio of Ni to Cu is 2 to 4:1. The application avoids the essential safety hazard existing in the original process, and realizes green and sustainable production of ethylenediamine.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation technology of ethylenediamine, in particular to a method for preparing ethylenediamine from ethanolamine as an initial raw material and a catalyst thereof. BACKGROUND

[0002] Ethylenediamine (EDA) is an important chemical raw material and fine chemical intermediate, which is widely used in the industries of pesticide, food, medicine, automobile, shipbuilding, civil construction, water treatment, papermaking, rubber, textile and electronics, and can be used as a basic raw material for epoxy resin curing agent, dye intermediate, electroplating liquid surfactant, lubricating oil additive, paper wet strength agent, soil conditioner, etc.

[0003] The main synthesis methods of ethylenediamine include dichloroethane method, ethylene glycol method, ethylene oxide method and ethanolamine method. In the early stage, the main industrial synthesis method of ethylenediamine was dichloroethane method, and dichloroethane was produced from petroleum-based chemicals, but this method had the disadvantages of poor product quality, high energy consumption, serious equipment corrosion, large amount of three wastes emission (US 5364971 A). Therefore, people have been exploring new methods and processes for preparing ethylenediamine, including using ethylene glycol as a raw material to prepare ethylenediamine by catalytic amination (the highest yield can reach 60%), generating a large amount of ethanolamine intermediate and piperazine, long-chain amine and other by-products, and the reaction conditions are very harsh (180℃, 30MPa, US 3270059 A). The ethylene oxide method has obvious disadvantages such as high cost, low product purity and low yield (4.5%, WO 2009083580 A1). In terms of reaction principle, the catalytic amination of ethanolamine (MEA) to prepare ethylenediamine is the most simple and ideal route, and the process basically has no three wastes emission, and produces high-value-added piperazine and the like. In the literatures and patents of the reported methods, noble metal catalysts (Ni-Re / γ-Al2O3 and Ni-Re-B / SiO2) are mostly used, and the yield of the target product ethylenediamine is low (US 5750790 A, 38.82% and US 6534441 B1, 31.32%).

[0004] In summary, the amination of ethanolamine to synthesize ethylenediamine under the action of a non-homogeneous non-noble metal catalyst is a green and sustainable process route. Therefore, it is of great significance to study a safe and high-yield ethylenediamine production method and the corresponding catalyst system suitable for industrial production. SUMMARY

[0005] The purpose of the present application is to solve the problems of the prior art and provide a method for preparing ethylenediamine. The method uses a core-shell structure catalyst to catalyze the amination of ethanolamine to synthesize ethylenediamine at a high yield. The catalyst has a core-shell structure, wherein the outer shell is a silica-alumina composite material. The limited internal space is conducive to the concentration of reactants, accelerates the collision of reactants with NH3 / H2 molecules, and thus improves the reaction efficiency. The self-coupling reaction and over-alkylation reaction of the product are inhibited, and the selectivity of the target product is improved. The double metal ratio of the metal core can regulate the electronic effect of the catalyst, thereby improving the dehydrogenation and hydrogenation activity of the catalyst. The present application avoids the inherent safety hazards of the original process and realizes the green and sustainable production of ethylenediamine.

[0006] The technical solution of the present application is:

[0007] A method for preparing ethylenediamine, comprising the following steps:

[0008] Ethanolamine is loaded into a reaction kettle loaded with a catalyst, and ammonia and hydrogen are sequentially introduced into the reaction kettle. The catalytic amination reaction occurs at 170-210 DEG C for 10-18 h to generate ethylenediamine;

[0009] Wherein, the mass ratio of ethanolamine to catalyst is 3-20:1; the ammonia pressure is 0.3-0.7 MPa; and the hydrogen pressure is 1-3 MPa.

[0010] The catalyst has a core-shell structure, which comprises a silica-alumina composite shell and a metal core. The metal core is composed of metal M1 and metal M2, which are Ni and Cu, respectively. The total molar amount of Ni and Cu accounts for 67-91% of the whole catalyst, and the molar ratio of Ni to Cu is 2-4:1.

[0011] The diameter of the metal core is 10-25 nm, and the thickness of the shell layer is 5-20 nm.

[0012] The preparation method of the catalyst comprises the following steps:

[0013] (1) Continuous preparation of the metal core:

[0014] Nitrate solution A and Na2CO3 solution B are separately injected at a speed of 5.00-15.00 mL / min using a high-pressure booster pump, and are mixed at a constant temperature of 50-70 DEG C through a membrane disperser. The turbid liquid is collected, centrifuged, washed to neutral, and dried at 80-100 DEG C for 10-24 h. Finally, the cooled catalyst precursor is ground into powder, calcined at 400-600 DEG C for 2-4 h at a heating rate of 5-10 DEG C / min, and metal oxide nanoparticles, i.e. the metal core, are obtained.

[0015] The concentration of the nitrate solution is 0.10-0.30M, and the concentration of the Na2CO3 solution is 0.20-0.60M.

[0016] The nitrate is copper nitrate and nickel nitrate, and the molar ratio of Ni:Cu is 2-4:1.

[0017] The metal oxide is CuO, NiO and NiO-CuO, and the particle size of the nanoparticle is 10-25nm.

[0018] (2) coating a shell layer outside the metal core;

[0019] The metal oxide nanoparticle is added into H2O to obtain a metal oxide suspension; ultrasonic dispersion is carried out for 30-60min, and then tetrapropylammonium hydroxide (TPAOH) is added and ultrasonic dispersion is carried out for 30-60min; then tetraethyl orthosilicate (TEOS corresponding to SiO2) is added dropwise and hydrolysis is carried out at 40-60℃; finally, a mixed solution of Al(NO3)3, NaOH and H2O is added dropwise into the above mixture, and stirring is carried out at room temperature for 1h; the above mixed solution is added into a hydrothermal kettle, and hydrothermal reaction is carried out at 160-180℃ for 24-48h to obtain a catalyst precursor; then calcination is carried out at 400℃-600℃ for 2-4h, and H2 reduction is carried out at 400℃-600℃ for 2-3h to obtain the final catalyst.

[0020] The concentration of the metal oxide suspension is 0.2-1wt%.

[0021] The molar ratio of TEOS:Al(NO3)3·9H2O:TPAOH:NaOH:H2O in the mixed solution is 2-20:1:20-150:200-1500:1500-10000.

[0022] The molar ratio of the metal oxide:(tetraethyl orthosilicate+Al(NO3)3·9H2O) is 0.1-1.0.

[0023] The substantial features of the present application are:

[0024] The core-shell structure of the silica-alumina coated Ni-Cu bimetallic heterogeneous catalyst adopted in the present application is continuously prepared; due to the existence of the silica-alumina shell, the service life of the catalyst can be improved. Through the precise design of the core-shell structure of the catalyst, the collision of the reactants with NH3 / H2 molecules can be accelerated, thereby improving the reaction efficiency; the self-coupling reaction and the over-alkylation reaction of the product can be inhibited, the selectivity of the target product can be improved, and the generation of by-products such as piperazine and long-chain amines can be reduced; further, the electronic effect of the catalyst can be regulated by regulating the bimetallic ratio of the metal core, thereby improving the dehydrogenation and hydrogenation activity of the catalyst.

[0025] Ultimately, by leveraging the advantages of its core-shell structure and the controllable shell structure, it is possible to achieve efficient and highly selective amination of ethanolamine-catalyzed ethylenediamine to ethylenediamine.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention provides a method for synthesizing ethylenediamine from ethanolamine, which overcomes the drawbacks of existing production processes, such as high difficulty, severe environmental pollution, and low yield. The method employs a membrane dispersion microreactor to continuously prepare the metal core of a core-shell catalyst, while using a silica-alumina composite shell. The catalyst used in this invention is simple to prepare, and both the catalyst shell support and the active metal core component are inexpensive and readily available.

[0028] The catalytic amination reaction conditions of this invention are relatively mild and the equipment requirements are not high, which improves the economic feasibility of the reaction. Due to the unique core-shell structure of the catalyst, there are fewer byproducts such as piperazine and long-chain amines. During the catalytic process, the conversion rate of ethanolamine can reach 81%, and the selectivity of ethylenediamine is 83%. At the same time, piperazine (PA) and triethylenediamine (TEDA) are obtained in yields of 11% and 5%, respectively (see Example 28 for details). Attached Figure Description

[0029] Figure 1 The catalyst 3Ni-1Cu obtained in Example 8 间歇 @12.5SiO2-1Al2O3-0.2 (corresponding to 3NiO-1CuO obtained in Example 1) 间歇 TEM image of nanoparticles;

[0030] Figure 2 The image shows a TEM image of the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 obtained in Example 8 (corresponding to the 3NiO-1CuO nanoparticles obtained in Example 3). Detailed Implementation

[0031] The synthetic route of this invention is shown in the reaction formula below:

[0032]

[0033] The technical features of the present invention are further illustrated below through examples:

[0034] Example 1: 3NiO-1CuO 间歇 Preparation of nanoparticles

[0035] To 100 mL of distilled water containing 3.00 g of polyethylene glycol (PEG-20000), 4.36 g of Ni(N03)2-6H20 (0.0150 mol), 1.21 g of Cu(N03)2-3H20 (0.0050 mol) were added. After stirring the solution for 30 min, 4.50 g of urea was added and the mixture was heated to 90 °C for 24 h. The precipitate was collected by centrifugation, washed with ethanol and distilled water, dried at 100 °C for 10 h and calcined at 400 °C for 4 h in air to obtain 3NiO-1CuO 间歇 nanoparticles.

[0036] Example 2: Preparation of 2NiO-1CuO nanoparticles

[0037] Solutions A [4.36 g of Ni(N03)2-6H20 (0.0150 mol), 1.21 g of Cu(N03)2-3H20 (0.0050 mol) dissolved in 100 mL of distilled water] and B [4.24 g of Na2C03(0.0400 mol) dissolved in 100 mL of distilled water] were separately injected at a rate of 5.00 mL / min through a membrane disperser (thermostated at 60 °C) and the turbid solution was collected, centrifuged, washed with deionized water and ethanol until neutral, and dried in an oven at 100 °C for 10 h. Finally, the cooled catalyst precursor was ground to a powder and calcined in a muffle furnace at 400 °C for 4 h with a heating rate of 5 °C / min to obtain 2NiO-1CuO nanoparticles (i.e., metal core).

[0038] Example 3: Preparation of 3NiO-1CuO nanoparticles

[0039] Solutions A [4.36 g of Ni(N03)2-6H20 (0.0150 mol), 1.21 g of Cu(N03)2-3H20 (0.0050 mol) dissolved in 100 mL of distilled water] and B [4.24 g of Na2C03(0.0400 mol) dissolved in 100 mL of distilled water] were separately injected at a rate of 5.00 mL / min through a membrane disperser (thermostated at 60 °C) and the turbid solution was collected, centrifuged, washed with deionized water and ethanol until neutral, and dried in an oven at 100 °C for 10 h. Finally, the cooled catalyst precursor was ground to a powder and calcined in a muffle furnace at 400 °C for 4 h with a heating rate of 5 °C / min to obtain 3NiO-1CuO nanoparticles.

[0040] Example 4: Preparation of 4NiO-1CuO nanoparticles

[0041] Solution A [5.82 g Ni(N03)2-6H20 (0.0200 mol), 1.21 g Cu(N03)2-3H20 (0.0050 mol) dissolved in 100 mL distilled water] and solution B [5.30 g Na2C03(0.0500 mol) dissolved in 100 mL distilled water] were injected separately at a rate of 5.00 mL / min using high pressure intensifier pumps, mixed through a membrane disperser (thermostated at 60 °C), the turbid solution was collected, centrifuged, washed with deionized water and ethanol until neutral, and dried in an oven at 100 °C for 10 h. Finally, the cooled catalyst precursor was ground to a powder and calcined in a muffle furnace to 400 °C for 4 h with a ramp rate of 5 °C / min to obtain 4NiO-lCuO nanoparticles.

[0042] Example 5: Preparation of Ni-Cu@Si02-0.2 catalyst

[0043] To 50 mL distilled water, 0.25 g NiO-CuO nanoparticles (3.30 mmol, obtained from Example 1-4) were added and subjected to 30 min ultrasonication. Then, 0.1394 g (i.e. 0.6691 mmol) of tetraethyl orthosilicate (TEOS) (corresponding to a shell reagent to metal core molar ratio of 0.2 - (molar amount of metal core calculated as the sum of moles of Ni and Cu)) and 10 mL NH3-H20 (25 wt%, 0.13 mol of ammonia contained) were added sequentially under ultrasonication (60 min) in an ultrasonic bath, followed by an additional 1 h of ultrasonication, centrifugation, washing with deionized water and ethanol washing until neutral, drying at 80 °C for 10 h, calcination at 400 °C for 4 h, H2reduction at 550 °C for 2 h to obtain 4 core-shell structured catalysts 3Ni-lCu@Si02-0.2, 2Ni-lCu@Si02-0.2, 3Ni-lCu@Si02-0.2 and 4Ni-lCu@Si02-0.2. 间歇 @Si02-0.2, 2Ni-lCu@Si02-0.2, 3Ni-lCu@Si02-0.2 and 4Ni-lCu@Si02-0.2.

[0044] Example 6: Preparation of Ni-Cu@Al203-0.2 catalyst

[0045] To 50 mL distilled water, 0.25 g NiO-CuO nanoparticles (3.30 mmol, obtained from Example 1-4) were added and sonicated for 30 min. Then 0.2510 g (i.e. 0.6691 mmol) of Al(NO3)3-9H2O (corresponding to a molar ratio of 0.2 of shell reagent to metal core) and 10 mL of NH3-H2O (25 wt%, 0.13 mol of ammonia contained) were added successively under sonication (60 min) in an ultrasonic bath, and sonicated for another 1 h, centrifuged, washed with deionized water and ethanol until neutral, dried at 80 °C for 10 h, calcined at 400 °C for 4 h, reduced with H2at 550 °C for 2 h to obtain four core-shell structured catalysts 3Ni-1Cu@Al2O3-0.2, 2Ni-1Cu@Al2O3-0.2, 3Ni-1Cu@Al2O3-0.2 and 4Ni-1Cu@Al2O3-0.2. 间歇 @Al2O3-0.2, 2Ni-1Cu@Al2O3-0.2, 3Ni-1Cu@Al2O3-0.2 and 4Ni-1Cu@Al2O3-0.2.

[0046] Example 7: Preparation of Ni-Cu@5SiO2-1Al2O3-0.2 catalyst

[0047] To 40 mL H2O, 0.25 g NiO-CuO nanoparticles (3.2761-3.3043 mmol, obtained from Example 1-4) were added and sonicated for 60 min, then 1.9320 g (i.e. 9.500 mmol) of TPAOH was added and sonicated for 60 min, and then 0.1744 g (i.e. 0.8371 mmol) of TEOS was added dropwise to the above mixture and hydrolyzed at 60 °C, and stirred at room temperature for 1 h. A mixture solution of 0.1105 g (i.e. 0.2946 mmol) of Al(NO3)3-9H2O, 3.2640 g (i.e. 81.60 mmol) of NaOH, 10 g (i.e. 555.56 mmol) of H2O was added dropwise to the above mixture, and then added to an autoclave, and hydrothermal reaction was carried out at 170 °C for 36 h to obtain a catalyst precursor, which was centrifuged, washed with deionized water and ethanol until neutral, dried at 80 °C for 10 h, calcined at 400 °C for 4 h, reduced with H2at 500 °C for 2 h to obtain four core-shell structured catalysts 3Ni-1Cu@5SiO2-1Al2O3-0.2, 2Ni-1Cu@5SiO2-1Al2O3-0.2, 3Ni-1Cu@5SiO2-1Al2O3-0.2 and 4Ni-1Cu@5SiO2-1Al2O3-0.2. 间歇 @5SiO2-1Al2O3-0.2, 2Ni-1Cu@5SiO2-1Al2O3-0.2, 3Ni-1Cu@5SiO2-1Al2O3-0.2 and 4Ni-1Cu@5SiO2-1Al2O3-0.2.

[0048] Example 8: Preparation of Ni-Cu@12.5SiO2-1Al2O3-0.2 catalyst

[0049] 0.25 g of NiO-CuO nanoparticles (3.2761–3.3043 mmol, obtained from Examples 1–4) were added to 40 mL of H2O and ultrasonically dispersed for 60 min. Then, 1.9320 g (9.500 mmol) of TPAOH was added and ultrasonically dispersed for another 60 min. Finally, 0.2098 g (1.007 mmol) of TEOS was added dropwise to the above mixed solution and hydrolyzed at 60 °C. The mixture was stirred at room temperature for 1 h. A mixed solution of 0.0533 g (0.1421 mmol) Al(NO3)3·9H2O, 3.2640 g (81.60 mmol) NaOH, and 10 g (555.56 mmol) H2O was added dropwise to the above mixture, and then added to a hydrothermal reactor. The mixture was hydrothermally reacted at 170 °C for 36 h to obtain the catalyst precursor. The precursor was centrifuged, washed with deionized water and ethanol until neutral, dried at 80 °C for 10 h, calcined at 400 °C for 4 h, and reduced to H2 at 500 °C for 2 h to obtain four core-shell structured catalysts: 3Ni-1Cu. 间歇 @12.5SiO2-1Al2O3-0.2, 2Ni-1Cu@12.5SiO2-1Al2O3-0.2, 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 and 4Ni-1Cu@12.5SiO2-1Al2O3-0.2.

[0050] The molar ratio of the metal core nanoparticles to the shell-forming agent is 0.1–0.5, and the shell-forming agent of the catalyst is tetraethyl orthosilicate.

[0051] Example 9: Preparation of Ni-Cu@25SiO2-1Al2O3-0.2 catalyst

[0052] 0.25 g of NiO-CuO nanoparticles (3.2761–3.3043 mmol, obtained from Examples 1–4) were added to 40 mL of H2O and ultrasonically dispersed for 60 min. Then, 1.9320 g (9.500 mmol) of TPAOH was added and ultrasonically dispersed for another 60 min. Finally, 0.2252 g (1.081 mmol) of TEOS was added dropwise to the above mixed solution and hydrolyzed at 60 °C. The mixture was stirred at room temperature for 1 h. A mixed solution of 0.0286 g (0.0762 mmol) Al(NO3)3·9H2O, 3.2640 g (81.60 mmol) NaOH, and 10 g (555.56 mmol) H2O was added dropwise to the above mixture, and then added to a hydrothermal reactor. The mixture was hydrothermally reacted at 170 °C for 36 h to obtain the catalyst precursor. The precursor was centrifuged, washed with deionized water and ethanol until neutral, dried at 80 °C for 10 h, calcined at 400 °C for 4 h, and reduced to H2 at 500 °C for 2 h to obtain four core-shell structured catalysts, 3Ni-1Cu. 间歇@25SiO2-1Al2O3-0.2, 2Ni-1Cu@25SiO2-1Al2O3-0.2, 3Ni-1Cu@25SiO2-1Al2O3-0.2 and 4Ni-1Cu@25SiO2-1Al2O3-0.2.

[0053] Example 10: Preparation of Ni-Cu@12.5SiO2-1Al2O3-0.1 catalyst

[0054] 0.25 g of NiO-CuO nanoparticles (3.2761–3.3043 mmol, obtained from Examples 1–4) were added to 40 mL of H2O and ultrasonically dispersed for 60 min. Then, 1.9320 g (9.500 mmol) of TPAOH was added and ultrasonically dispersed for another 60 min. Finally, 0.1049 g (0.5035 mmol) of TEOS was added dropwise to the above mixed solution and hydrolyzed at 60 °C. The mixture was then stirred at room temperature for 1 h. A mixed solution of 0.0266 g (0.0709 mmol) Al(NO3)3·9H2O, 3.2640 g (81.60 mmol) NaOH, and 10 g (555.56 mmol) H2O was added dropwise to the above mixture, and then added to a hydrothermal reactor. The mixture was hydrothermally reacted at 170 °C for 36 h to obtain the catalyst precursor. The precursor was centrifuged, washed with deionized water and ethanol until neutral, dried at 80 °C for 10 h, calcined at 400 °C for 4 h, and reduced to H2 at 500 °C for 2 h to obtain four core-shell structured catalysts, 3Ni-1Cu. 间歇 @12.5SiO2-1Al2O3-0.2, 2Ni-1Cu@12.5SiO2-1Al2O3-0.2, 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 and 4Ni-1Cu@12.5SiO2-1Al2O3-0.2.

[0055] Example 11: Preparation of Ni-Cu@12.5SiO2-1Al2O3-0.3 catalyst

[0056] 0.25 g of NiO-CuO nanoparticles (3.2761–3.3043 mmol, obtained from Examples 1–4) were added to 40 mL of H2O and ultrasonically dispersed for 60 min. Then, 1.9320 g (9.500 mmol) of TPAOH was added and ultrasonically dispersed for another 60 min. Finally, 0.3147 g (1.5106 mmol) of TEOS was added dropwise to the above mixed solution and hydrolyzed at 60 °C. The mixture was then stirred at room temperature for 1 h. A mixed solution of 0.0799 g (0.2130 mmol) Al(NO3)3·9H2O, 3.2640 g (81.60 mmol) NaOH, and 10 g (555.56 mmol) H2O was added dropwise to the above mixture, and then added to a hydrothermal reactor. The mixture was hydrothermally reacted at 170 °C for 36 h to obtain the catalyst precursor. The precursor was centrifuged, washed with deionized water and ethanol until neutral, dried at 80 °C for 10 h, calcined at 400 °C for 4 h, and reduced to H2 at 500 °C for 2 h to obtain four core-shell structured catalysts, 3Ni-1Cu. 间歇 @12.5SiO2-1Al2O3-0.3, 2Ni-1Cu@12.5SiO2-1Al2O3-0.3, 3Ni-1Cu@12.5SiO2-1Al2O3-0.3 and 4Ni-1Cu@12.5SiO2-1Al2O3-0.3.

[0057] Example 12: Preparation of Ni-Cu@12.5SiO2-1Al2O3-0.4 catalyst

[0058] 0.25 g of NiO-CuO nanoparticles (3.2761–3.3043 mmol, obtained from Examples 1–4) were added to 40 mL of H2O and ultrasonically dispersed for 60 min. Then, 1.9320 g (9.500 mmol) of TPAOH was added and ultrasonically dispersed for another 60 min. Finally, 0.4196 g (2.0141 mmol) of TEOS was added dropwise to the above mixed solution and hydrolyzed at 60 °C. The mixture was then stirred at room temperature for 1 h. A mixed solution of 0.1065 g (0.2839 mmol) Al(NO3)3·9H2O, 3.2640 g (81.60 mmol) NaOH, and 10 g (555.56 mmol) H2O was added dropwise to the above mixture, and then added to a hydrothermal reactor. The mixture was hydrothermally reacted at 170 °C for 36 h to obtain the catalyst precursor. The precursor was centrifuged, washed with deionized water and ethanol until neutral, dried at 80 °C for 10 h, calcined at 400 °C for 4 h, and reduced to H2 at 500 °C for 2 h to obtain four core-shell structured catalysts: 3Ni-1Cu. 间歇@12.5SiO2-1Al2O3-0.4, 2Ni-1Cu@12.5SiO2-1Al2O3-0.4, 3Ni-1Cu@12.5SiO2-1Al2O3-0.4, and 4Ni-1Cu@12.5SiO2-1Al2O3-0.4.

[0059] Example 13: Preparation of Ni-Cu@12.5SiO2-1Al2O3-0.5 catalyst

[0060] 0.25 g of NiO-CuO nanoparticles (3.2761-3.3043 mmol, obtained from Example 1-4) were added to 40 mL of H2O and ultrasonically dispersed for 60 min, 1.9320 g (i.e. 9.500 mmol) of TPAOH was added and ultrasonically dispersed for 60 min, and then 0.5245 g (i.e. 2.5176 mmol) of TEOS was added dropwise to the above mixture, which was hydrolyzed at 60°C and stirred at room temperature for 1 h. A mixture of 0.1332 g (i.e. 0.3550 mmol) of Al(NO3)3.9H2O, 3.2640 g (i.e. 81.60 mmol) of NaOH, and 10 g (i.e. 555.56 mmol) of H2O was added dropwise to the above mixture, which was then added to an autoclave, and hydrothermally reacted at 170°C for 36 h to obtain a catalyst precursor, which was centrifuged, washed with deionized water and ethanol until neutral, dried at 80°C for 10 h, calcined at 400°C for 4 h, and reduced with H2at 500°C for 2 h to obtain four core-shell structure catalysts 3Ni-1Cu@12.5SiO2-1Al2O3-0.5, 2Ni-1Cu@12.5SiO2-1Al2O3-0.5, 1Ni-1Cu@12.5SiO2-1Al2O3-0.5, and 0Ni-1Cu@12.5SiO2-1Al2O3-0.5. 间歇 @12.5SiO2-1Al2O3-0.5, 2Ni-1Cu@12.5SiO2-1Al2O3-0.5, 3Ni-1Cu@12.5SiO2-1Al2O3-0.5, and 4Ni-1Cu@12.5SiO2-1Al2O3-0.5.

[0061] The shell layer of the catalyst obtained above is SiO2or Al2O3or a mixture of SiO2and Al2O3;

[0062] The molar amount of the metal nanoparticles is the actual content measured by ICP;

[0063] The metal M1in the metal core is Ni, and the metal M2is Cu; the molar ratio of the metals M1and M2is 2-4:1;

[0064] The thickness and pore size of the shell layer of the catalyst are determined by the ratio of the oxide shell layer (shell-forming reagent) to the metal, and the molar ratio of the metal to the shell-forming reagent is 1:0.1-1.0;

[0065] The catalyst is represented by xM1-yM2@mSiO2-nAl2O3-z, wherein M1 and M2 represent metals, x and y represent the molar ratio of M1 to M2 in the catalyst, m and n represent the molar ratio of SiO2 to Al2O3 in the catalyst, and z represents the molar ratio of mSiO2-nAl2O3 to xM1-yM2 in the catalyst.

[0066] Example 14: Catalytic amination of ethanolamine

[0067] The reaction was carried out in a 15 mL stainless steel autoclave, and the catalyst 4Ni-1Cu@SiO2-0.2 (0.20 g) obtained in Example 5 and ethanolamine (2.00 g) were added. Before the reaction, the reactor was purged with N2 five times to replace the residual air. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst, N-methylpyrrolidone was added as an internal standard, and gas chromatography analysis was performed. The conversion of ethanolamine was 57%, the selectivity of ethylenediamine was 79%, the selectivity of piperazine was 12%, and the selectivity of triethylenediamine was 8%.

[0068] Example 15: Catalytic amination of ethanolamine

[0069] The reaction was carried out in a 15 mL stainless steel autoclave, and the catalyst 3Ni-1Cu@SiO2-0.2 (0.20 g) obtained in Example 5 and ethanolamine (2.00 g) were added. Before the reaction, the reactor was purged with N2 five times to replace the residual air. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst, N-methylpyrrolidone was added as an internal standard, and gas chromatography analysis was performed. The conversion of ethanolamine was 54%, the selectivity of ethylenediamine was 86%, the selectivity of piperazine was 8%, and the selectivity of triethylenediamine was 5%.

[0070] Example 16: Catalytic amination of ethanolamine

[0071] A 15 mL stainless steel autoclave was charged with the catalyst 2Ni-1Cu@SiO2-0.2 (0.20 g) obtained in Example 5 and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 50%, the selectivity of ethylenediamine was 87%, the selectivity of piperazine was 8%, and the selectivity of triethylenediamine was 4%.

[0072] Example 17: Catalytic amination of ethanolamine

[0073] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@Al2O3-0.2 (0.20 g) obtained in Example 6 and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 69%, the selectivity of ethylenediamine was 73%, the selectivity of piperazine was 9%, and the selectivity of triethylenediamine was 4%.

[0074] Example 18: Catalytic amination of ethanolamine

[0075] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@5SiO2-1Al2O3-0.2 (0.20 g) obtained in Example 7 and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 64%, the selectivity of ethylenediamine was 79%, the selectivity of piperazine was 11%, and the selectivity of triethylenediamine was 4%.

[0076] Example 19: Catalytic amination of ethanolamine

[0077] The reaction was carried out in a 15 mL stainless steel reactor, with the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 (0.20 g) obtained in Example 8 and ethanolamine (2.00 g) added. Before the reaction, the reactor was purged five times with N2 to replace residual air. Then, 0.5 MPa NH3 and 1.0 MPa H2 were introduced, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst, and N-methylpyrrolidone was added as an internal standard for gas chromatography analysis. The conversion rate of ethanolamine was 61%, the selectivity for ethylenediamine was 84%, the selectivity for piperazine was 12%, and the selectivity for triethylenediamine was 3%.

[0078] Example 20: Catalytic amination reaction of ethanolamine

[0079] The reaction was carried out in a 15 mL stainless steel reactor, with the catalyst 3Ni-1Cu obtained in Example 8 added. 间歇 The reaction mixture consisted of 12.5SiO2-1Al2O3-0.2 (0.20 g) and ethanolamine (2.00 g). Before the reaction, the reactor was purged five times with N2 to replace residual air. Then, 0.5 MPa NH3 and 1.0 MPa H2 were introduced, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and N-methylpyrrolidone was added as an internal standard for gas chromatography analysis. The conversion rate of ethanolamine was 47%, the selectivity for ethylenediamine was 62%, the selectivity for piperazine was 17%, and the selectivity for triethylenediamine was 10%.

[0080] Example 21: Catalytic amination reaction of ethanolamine

[0081] The reaction was carried out in a 15 mL stainless steel reactor, with the catalyst 3Ni-1Cu@25SiO2-1Al2O3-0.2 (0.20 g) obtained in Example 9 and ethanolamine (2.00 g) added. Before the reaction, the reactor was purged five times with N2 to replace residual air. Then, 0.5 MPa NH3 and 1.0 MPa H2 were introduced, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst, and N-methylpyrrolidone was added as an internal standard for gas chromatography analysis. The conversion rate of ethanolamine was 57%, the selectivity for ethylenediamine was 85%, the selectivity for piperazine was 12%, and the selectivity for triethylenediamine was 3%.

[0082] Example 22: Catalytic amination reaction of ethanolamine

[0083] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.1 (0.20 g) and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 58%, the selectivity of ethylenediamine was 73%, the selectivity of piperazine was 11%, and the selectivity of triethylenediamine was 4%.

[0084] Example 23: Catalytic amination of ethanolamine

[0085] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.1 (0.20 g) and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 58%, the selectivity of ethylenediamine was 73%, the selectivity of piperazine was 11%, and the selectivity of triethylenediamine was 4%.

[0086] Example 24: Catalytic amination of ethanolamine

[0087] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.1 (0.20 g) and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 58%, the selectivity of ethylenediamine was 73%, the selectivity of piperazine was 11%, and the selectivity of triethylenediamine was 4%.

[0088] Example 25: Catalytic amination of ethanolamine

[0089] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.5 (0.20 g) obtained in Example 13 and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 12 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 67%, the selectivity of ethylenediamine was 56%, the selectivity of piperazine was 20%, and the selectivity of triethylenediamine was 16%.

[0090] Example 26: Catalytic amination of ethanolamine

[0091] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 (0.20 g) obtained in Example 8 and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (180 °C) with a stirring rate of 1500 rpm. After 14 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 64%, the selectivity of ethylenediamine was 83%, the selectivity of piperazine was 12%, and the selectivity of triethylenediamine was 4%.

[0092] Example 27: Catalytic amination of ethanolamine

[0093] A 15 mL stainless steel autoclave was charged with the catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 (0.20 g) obtained in Example 8 and ethanolamine (2.00 g). The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (190 °C) with a stirring rate of 1500 rpm. After 14 h of reaction, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 70%, the selectivity of ethylenediamine was 81%, the selectivity of piperazine was 13%, and the selectivity of triethylenediamine was 5%.

[0094] Example 28: Catalytic amination of ethanolamine

[0095] The catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 (0.40 g) obtained in Example 8 and ethanolamine (2.00 g) were added in a 15 mL stainless steel autoclave. The reactor was purged with N2 five times to replace the residual air before the reaction. Then, 0.5 MPa NH3 and 1.0 MPa H2 were charged, and the reaction was carried out at a constant temperature (190℃) with a stirring speed of 1500 rpm. After 14 h, the liquid product was separated from the catalyst and analyzed by gas chromatography with N-methylpyrrolidone as an internal standard. The conversion of ethanolamine was 81%, the selectivity of ethylenediamine was 83%, the selectivity of piperazine was 11%, and the selectivity of triethylenediamine was 5%.

[0096] As shown in Examples 14-16, when the molar ratio of metal Ni to Cu was 3:1, the conversion of ethanolamine was 54%, and the selectivity of ethylenediamine reached a maximum of 86%. The reason is that a high proportion of Cu is more conducive to the dehydrogenation of ethanolamine, which promotes the conversion of ethanolamine, while a lower proportion of Cu promotes the dispersion of Ni, which is more conducive to the formation of ethylenediamine, thereby improving the selectivity of ethylenediamine.

[0097] In the reductive amination reaction, the acidity and basicity of the catalyst have a great influence on the conversion of the substrate and the selectivity of the product. The acidity and basicity of the catalyst prepared in this study are mainly affected by the composition and thickness of the shell layer. Therefore, Examples 17-25 systematically investigate the effects of different shell layer compositions and shell layer thicknesses on the reaction. The catalyst 3Ni-1Cu@12.5SiO2-1Al2O3-0.2 has the best catalytic performance, with a conversion of ethanolamine of 61%, a selectivity of ethylenediamine of 84%, and a highest yield of EDA of 51%. The reason is that this catalyst has appropriate acid strength, an appropriate amount of acid sites, and appropriate basic sites, which are helpful for promoting the breaking of O-H bonds, C-H bonds, and the adsorption of MEA and intermediates in the condensation steps of ketones and ammonia, as well as the desorption of EDA, thereby promoting the catalytic amination reaction of MEA.

[0098] Example 20 is a catalyst prepared by using metal nanoparticles prepared by a batch method, and its catalytic performance is significantly lower than that of metal nanoparticles prepared by a continuous membrane dispersion microreactor.

[0099] Examples 26-28 give some process condition optimization data. When the reaction conditions are: reaction temperature 190℃, reaction time 14 h, MEA to catalyst mass ratio 5:1, ammonia pressure 0.5 MPa, and hydrogen pressure 1 MPa, the conversion of MEA reaches 81%, the selectivity of EDA is 83%, and the yield of EDA is 67%.

[0100] The details of the present application are known in the art.

Claims

1. A process for the production of ethylenediamine characterized by, The method comprises the following steps: The ethanolamine is loaded into a catalyst-loaded reaction kettle, ammonia and hydrogen are sequentially introduced into the reaction kettle, and a catalytic amination reaction is generated to produce ethylenediamine at 170-210 DEG C for 10-18 h; The mass ratio of ethanolamine to catalyst is 3-20:1, the ammonia pressure is 0.3-0.7 MPa, and the hydrogen pressure is 1-3 MPa; The catalyst has a core-shell structure, and is composed of a silica-alumina composite shell and a metal core; the metal core is metal M1 and metal M2, which are Ni and Cu respectively; the total molar amount of Ni and Cu accounts for 67-91% of the whole catalyst, and the molar ratio of metal Ni to Cu is 2-4:

1. The preparation method of the catalyst with a core-shell structure comprises the following steps: (1) Continuous preparation of the metal core: Nitrate solution A and Na2CO3 solution B are separately injected at a speed of 5.00-15.00 mL / min using a high-pressure intensifier pump, and are mixed at a constant temperature of 50-70 DEG C through a membrane disperser; the turbid liquid is collected, centrifuged, washed to neutral, and dried at 80-100 DEG C for 10-24 h; finally, the cooled catalyst precursor is ground into powder, calcined at 400-600 DEG C for 2-4 h at a heating rate of 5-10 DEG C / min, and metal oxide nanoparticles are obtained; The concentration of the nitrate solution is 0.10-0.30 M, and the concentration of the Na2CO3 solution is 0.20-0.60 M; The nitrate is copper nitrate and nickel nitrate; the molar ratio of Ni to Cu is 2-4:1; (2) Coating a shell layer outside the metal core; The metal oxide nanoparticles are added to H2O to obtain a metal oxide suspension; ultrasonic dispersion is carried out for 30-60 min, and then tetrapropylammonium hydroxide is added and ultrasonic dispersion is carried out for 30-60 min; then, tetraethyl orthosilicate is added dropwise, and hydrolysis is carried out at 40-60 DEG C; finally, an Al(NO3)3·9H2O, NaOH and H2O mixed solution is added dropwise to the above mixture, stirring is carried out, and then the mixture is added to an autoclave, and hydrothermal reaction is carried out at 160-180 DEG C for 24-48 h; the catalyst precursor is obtained, and then calcination is carried out at 400-600 DEG C for 2-4 h, and H2 reduction is carried out at 400-600 DEG C for 2-3 h to obtain the final catalyst; The concentration of the metal oxide suspension is 0.2-1 wt%; The molar ratio of TEOS: Al(NO3)3·9H2O: TPAOH: NaOH: H2O in the mixed solution is 2-20:1:20-150:200-1500:1500-10000; The molar ratio of the metal oxide to (tetraethyl orthosilicate+Al(NO3)3·9H2O) is 0.1-1.0; The metal oxide is CuO, NiO and NiO-CuO.

2. The process for the production of ethylenediamine as claimed in claim 1, characterized in that The diameter of the metal core is 10-25 nm, and the thickness of the shell layer is 5-20 nm.

Images