A method for producing ethylamine by one-step reaction from acetonitrile

Abstract

The application discloses a method for preparing ethylamine by one-step reaction of acetonitrile, which comprises the following steps: contacting hydrogen and acetonitrile with a catalyst in a reactor, and reacting to obtain ethylamine; the ethylamine is selected from at least one of ethylamine, diethylamine and triethylamine; the catalyst can catalyze the conversion of acetonitrile to prepare ethylamine efficiently in one step, and can realize the adjustment among different output proportions of ethylamine, diethylamine and triethylamine through the fine adjustment of catalyst composition and the change of process conditions, so as to better adapt to market demand; the catalyst is composed of a carrier and a noble metal component and a transition metal component supported on the surface of the carrier; the noble metal component is selected from at least two of platinum, palladium, ruthenium and iridium; the transition metal component is selected from at least one of zinc, copper, iron and nickel; in the catalyst, the mass ratio of the noble metal component, the transition metal component and the carrier is 0.002-0.02:0.005-0.05:1; wherein the mass of the noble metal component and the transition metal component is calculated according to the mass of metal elements.

Description

Technical Field

[0001] This invention relates to a method for preparing ethylamine from acetonitrile in a one-step reaction, belonging to the field of chemical engineering. Background Technology

[0002] Ethylamines typically include ethylamine (EA), diethylamine (DEA), and triethylamine (TEA). These three ethylamines are important fine chemical intermediates, used in the production of numerous pharmaceutical intermediates, dye intermediates, preservatives, emulsifiers, and polymerization inhibitors.

[0003] The main methods for producing ethylamine include ethylene ammoniation, acetaldehyde ammoniation, and ethanol hydroammoniation. Among these, ethanol hydroammoniation is currently the mainstream process. This process uses ethanol as a raw material and, through hydroammoniation, can simultaneously produce three types of ethylamines in one step. Furthermore, the proportion of the three ethylamines in the product is adjustable within a certain range, offering good technical and economic advantages. However, this technology also suffers from the problem of abundant azeotropic substances in the reactor outlet material due to the production of water as a byproduct, resulting in extremely high subsequent separation costs. In addition, the adjustable range of the proportions of the three ethylamines in the product is relatively narrow, making it difficult to adapt to the ever-changing market demand for these three ethylamines.

[0004] Three types of ethylamines can be effectively prepared from acetonitrile via a one-step hydrogenation reaction. The reaction process has high atom utilization and produces no water byproduct. Compared to the hydroammoniation of ethanol, this method has numerous advantages in product distribution and separation.

[0005] Currently, acetonitrile is mainly a byproduct of acrylonitrile plants. With the gradual expansion of acrylonitrile production capacity in my country, there is a surplus of this byproduct, which has limited uses. Furthermore, acetonitrile can also be efficiently synthesized through the amination of methyl acetate, a major chemical product in my country's coal chemical industry. Therefore, developing a continuous production process for ethylamine from acetonitrile hydrogenation can not only utilize the acetonitrile byproduct from acrylonitrile plants, solving the problem of its application, but also broaden the industrial chain of coal chemical enterprises, aligning with my country's basic national conditions. Simultaneously, this technology can replace the existing ethanol hydrogenation amination technology for ethylamine, reducing subsequent separation costs and contributing to energy conservation and emission reduction. Summary of the Invention

[0006] The key to realizing the industrial application of the technology for the continuous hydrogenation of acetonitrile to ethylamine lies in the development of a high-performance catalyst for the continuous hydrogenation of acetonitrile to ethylamine.

[0007] The purpose of this invention is to provide an acetonitrile hydrogenation catalyst and its application in the synthesis of ethylamine, in response to the above-mentioned needs.

[0008] According to one aspect of the present invention, a method for preparing ethylamine from acetonitrile in a one-step reaction is provided, characterized in that...

[0009] At least the following steps are included:

[0010] Hydrogen and acetonitrile are reacted with a catalyst in a reactor to produce ethylamine.

[0011] The ethylamine is selected from at least one of ethylamine, diethylamine, and triethylamine;

[0012] The catalyst is composed of a support and noble metal components and transition metal components supported on the surface of the support;

[0013] The precious metal component is selected from at least two of platinum, palladium, ruthenium, and iridium.

[0014] The transition metal component is selected from at least one of zinc, copper, iron and nickel.

[0015] In the catalyst, the mass ratio of noble metal component, transition metal component and support is 0.002-0.02:0.005-0.05:1;

[0016] The mass of the precious metal component and the transition metal component is expressed as the mass of the metal element.

[0017] The catalyst is obtained through at least the following steps:

[0018] The support was immersed in an aqueous solution containing a noble metal component precursor and a transition metal component precursor, allowed to stand, dried (I), calcined (I), and reduced with hydrogen to obtain the catalyst.

[0019] The noble metal component precursor is selected from at least two of chloroplatinic acid, tetraammineplatinum chloride, platinum nitrate, palladium nitrate, tetraamminepalladium chloride, ammonium hexachlororuthenate, ruthenium nitrate, and chloroiridium acid;

[0020] The transition metal component precursor is selected from at least one of zinc nitrate, copper nitrate, iron nitrate, and nickel nitrate;

[0021] The temperature of the drying process I is 100–150°C;

[0022] The drying time for step I is 4–20 hours;

[0023] The temperature of the calcination I is 450–600°C;

[0024] The roasting time for step I is 2 to 10 hours;

[0025] The temperature for hydrogen reduction is 400–550°C;

[0026] The hydrogen reduction time is 1 to 10 hours.

[0027] The carrier is obtained through the following steps:

[0028] The modified molecular sieve, amorphous silicon-containing compound precursor, amorphous aluminum-containing compound precursor, amorphous zirconium-containing compound precursor, organic acid, additives and water are mixed, kneaded, extruded into strips, dried (II), and calcined (II) to obtain the carrier.

[0029] The amorphous silicon-containing compound precursor is selected from at least one of silica, silica sol, and calcium silicate;

[0030] The amorphous aluminum-containing compound precursor is selected from at least one of aluminosilicate, kaolin, diatomite, and pseudoboehmite;

[0031] The amorphous zirconium-containing compound precursor is selected from at least one of zirconium oxide, zirconium sol and zirconium phosphate;

[0032] The organic acid is selected from at least one of acetic acid, citric acid, acrylic acid, propionic acid, salicylic acid, and tartaric acid;

[0033] The additive is selected from at least one of carbon black, starch, stearic acid, guar gum, polyvinyl alcohol, polyethylene glycol, dodecyl phosphate, sodium dodecyl sulfonate, and benzalkonium chloride palmitate.

[0034] The mass ratio of the modified molecular sieve, amorphous silicon-containing compound precursor, amorphous aluminum-containing compound precursor, amorphous zirconium-containing compound precursor, organic acid, and auxiliaries is 5–9:2–4:2–4:0.5–2:0.3–0.6:1.

[0035] The temperature of the drying II process is 100–150°C;

[0036] The drying time for step II is 4–20 hours;

[0037] The temperature of the second roasting step is 500–700°C;

[0038] The roasting time for the second stage is 2 to 10 hours.

[0039] The modified molecular sieve is obtained through the following steps:

[0040] Sodium-type molecular sieves are immersed in a modified solution for ion modification, then washed with water, dried (III), calcined (III), and treated with high-temperature ammonia to obtain the modified molecular sieves.

[0041] The sodium-type molecular sieve is selected from at least one of type A molecular sieve, type X molecular sieve, and type L molecular sieve;

[0042] The modified solution contains a lithium source and / or a beryllium source;

[0043] The lithium source is selected from at least one of lithium nitrate and lithium chloride;

[0044] The beryllium source is selected from at least one of beryllium nitrate and beryllium chloride;

[0045] The concentration of metal ions in the modified solution is 0.3–1.0 mol / L.

[0046] The temperature for ion modification is 60–80°C;

[0047] The ion modification time is 1–8 hours;

[0048] The liquid-to-solid ratio of the ion-modified solution is 6–12:1 mL / g;

[0049] The temperature of the drying III process is 100–150°C;

[0050] The drying time for step III is 4–20 hours;

[0051] The temperature of calcination III is 400–600°C;

[0052] The roasting time for III is 2–10 hours;

[0053] The temperature for the high-temperature ammonia treatment is 500–700°C;

[0054] The high-temperature ammonia treatment time is 1–8 hours;

[0055] The atmosphere for the high-temperature ammonia treatment is a 10-20 wt% ammonia atmosphere, with the remainder being inert gases.

[0056] The reactor is selected from at least one of fixed bed, fluidized bed and moving bed.

[0057] The mass hourly space velocity (MSV) of the acetonitrile is 0.1–10 h⁻¹. -1 ;

[0058] The molar ratio of hydrogen to acetonitrile is 2 to 8:1;

[0059] The reaction temperature is 100–250°C;

[0060] The reaction pressure is 0.1–2.0 MPa.

[0061] The beneficial effects that this invention can produce include:

[0062] 1) The active component in the acetonitrile hydrogenation catalyst provided by this invention is an optimized and highly dispersed composite metal active site, which can effectively adsorb and activate hydrogen molecules and acetonitrile molecules and catalyze their efficient conversion.

[0063] 2) The support in the acetonitrile hydrogenation catalyst provided by this method comprises modified molecular sieves, amorphous silicon-containing compounds, amorphous aluminum-containing compounds, and amorphous zirconium-containing compounds. The support is integrally prepared using an optimized preparation scheme, mainly serving to disperse and stabilize the composite metal active sites, provide a suitable physicochemical microenvironment for the hydrogenation active components, promote their efficient catalytic activity, and improve the catalyst's mass and heat transfer capacity and resistance to coking and deactivation.

[0064] 3) The preparation method of the acetonitrile hydrogenation catalyst provided by the present invention is simple, has good reproducibility, and is suitable for large-scale industrial production.

[0065] 4) The acetonitrile hydrogenation catalyst provided by this invention has the characteristics of high catalytic activity, good selectivity and long life. It can catalyze the hydrogenation of acetonitrile to prepare ethylamine in one step with high efficiency, and can realize the adjustment of the production ratio of ethylamine, diethylamine and triethylamine, thus adapting to market demand. Detailed Implementation

[0066] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.

[0067] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0068] Example 1: Preparation of modified molecular sieves Z1-Z5

[0069] The sodium molecular sieve matrix was added to the modified precursor solution for ion modification treatment. The modification treatment was then repeated once. The product was washed with deionized water, dried in an oven, and calcined in a muffle furnace to obtain the modified semi-finished product.

[0070] The modified semi-finished products were subjected to high-temperature treatment in ammonia gas of a certain concentration with nitrogen as the diluent to obtain modified molecular sieves Z1 to Z5.

[0071] The preparation conditions for the above-mentioned modified molecular sieves, including the type of sodium molecular sieve matrix, the type and concentration of modified precursors, the liquid-solid ratio of ion modification, the temperature and time of ion modification treatment, the drying temperature and time, the calcination temperature and time, the concentration of ammonia gas used for ammonia treatment, and the ammonia treatment temperature and time, are shown in Table 1.

[0072] Table 1 Preparation conditions of modified molecular sieves Z1 to Z5

[0073]

[0074]

[0075] Example 2: Preparation of carriers B1-B5

[0076] The modified molecular sieve prepared in Example 1, the amorphous silicon-containing compound precursor, the amorphous aluminum-containing compound precursor, the amorphous zirconium-containing compound precursor, the organic acid, the additives and water were mixed, kneaded, extruded into strips, dried in an oven and calcined in a muffle furnace to obtain the carriers B1 to B5.

[0077] The types and quantities of modified molecular sieves used in the preparation of the above-mentioned carriers, the weight and quantity of amorphous silicon-containing compound precursors, the quantity of amorphous aluminum-containing compound precursors, the quantity of amorphous zirconium-containing compound precursors, the types and quantities of organic acids, the types and quantities of auxiliaries, the drying temperature and drying time, and the calcination temperature and calcination time are shown in Table 2.

[0078] Table 2 Preparation conditions of carriers B1 to B5*

[0079]

[0080]

[0081] *Soluble calculations are based on a dry basis.

[0082] Example 3: Preparation of catalysts Cat.1 to Cat.7

[0083] The saturated water absorption of the carrier in Example 2 was determined using the saturated water absorption method. Then, based on the saturated water absorption, the target loading of the noble metal component, and the target loading of the transition metal component, the concentrations of the noble metal component precursor and the transition metal component precursor in the modified solution were calculated. Based on the above calculation results, a modified solution containing both the noble metal component precursor and the transition metal precursor was prepared.

[0084] The modified solution was uniformly added to the support prepared in Example 2 until adsorption saturation, then allowed to stand at room temperature for 24 hours, dried in an oven, calcined in a muffle furnace, and then reduced in a hydrogen atmosphere to obtain catalysts Cat.1 to Cat.7.

[0085] The preparation conditions for the catalysts, including the types of supports used, the loading of noble metal precursors (based on noble metal elements), the loading of transition metal precursors (based on transition metal elements), the drying temperature and drying time, the calcination temperature and calcination time, and the hydrogen reduction temperature and hydrogen reduction time, are shown in Table 3.

[0086] Table 3 Preparation conditions of catalysts Cat.1 to Cat.7

[0087]

[0088]

[0089] Comparative Example 1

[0090] Comparative Example 1 support was prepared using unmodified sodium-type X molecular sieve according to the preparation method of support B2 in Example 2. Then, using the comparative example 1 support as the parent material, the comparative example 1 catalyst was prepared according to the preparation method of catalyst Cat.2 in Example 3.

[0091] Comparative Example 2

[0092] Using carrier B2 from Example 2 as the carrier, and following the preparation method of catalyst Cat.3 from Example 3, but omitting the noble metal component, catalyst Comparative Example 2 was prepared.

[0093] Comparative Example 3

[0094] Using carrier B2 from Example 2 as the carrier, and following the preparation method of catalyst Cat.3 from Example 3, but omitting the transition metal component, catalyst Comparative Example 3 was prepared.

[0095] Example 4: Evaluation of the acetonitrile hydrogenation activity of the catalyst

[0096] The acetonitrile hydrogenation activity of catalysts Cat.1–Cat.7 prepared in Example 3 and the comparative catalyst was evaluated using a fixed-bed reactor with an inner diameter of 9 mm and a catalyst loading of 2 mL. Methyl acrylate and hydrogen were introduced to evaluate the reaction. The products were analyzed online using an Agilent 7890A chromatograph. The catalyst activity was evaluated based on indicators such as the conversion rate of acetonitrile in the feed and the selectivity of ethylamines (ethylamine, diethylamine, and triethylamine). The calculation methods for each indicator are as follows:

[0097]

[0098] [Acetonitrile] 进 The molar flow rate (mol / h) of acetonitrile at the reactor inlet; [acetonitrile] 出 [Ethylamine] 出 [Diethylamine] 出 and [triethylamine] 出 The values ​​represent the molar flow rates (mol / h) of acetonitrile, ethylamine, diethylamine, and triethylamine at the reactor outlet, respectively. The catalysts, reaction conditions, and catalyst activities for experiments exp1–exp12 are shown in Table 4.

[0099] Table 4. Reaction conditions and catalyst activity for experiments exp1–exp12

[0100]

[0101]

[0102] In the experiments shown in Table 4, samples were taken and analyzed every 5 hours. The results in the table are the average values ​​over 50 hours. Experiment exp2 was run continuously for 1000 hours, and no significant decrease in conversion or selectivity was observed, indicating that the catalyst has good stability.

[0103] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing ethylamine from acetonitrile in a one-step reaction, characterized in that, At least the following steps are included: Hydrogen and acetonitrile are reacted with a catalyst in a reactor to produce ethylamine. The ethylamine is selected from at least one of ethylamine, diethylamine, and triethylamine; The catalyst is composed of a support and noble metal components and transition metal components supported on the surface of the support; The precious metal component is selected from at least two of platinum, palladium, ruthenium, and iridium. The transition metal component is selected from at least one of zinc, copper, iron and nickel. In the catalyst, the mass ratio of noble metal component, transition metal component and support is 0.002-0.02:0.005-0.05:1; The mass of the precious metal component and the transition metal component is expressed as the mass of the metal element.

2. The method according to claim 1, characterized in that, The catalyst is obtained through at least the following steps: The support was immersed in an aqueous solution containing a noble metal component precursor and a transition metal component precursor, allowed to stand, dried (I), calcined (I), and reduced with hydrogen to obtain the catalyst. The noble metal component precursor is selected from at least two of chloroplatinic acid, tetraammineplatinum chloride, platinum nitrate, palladium nitrate, tetraamminepalladium chloride, ammonium hexachlororuthenate, ruthenium nitrate, and chloroiridium acid; The transition metal component precursor is selected from at least one of zinc nitrate, copper nitrate, iron nitrate, and nickel nitrate; The temperature of the drying process I is 100–150°C; The drying time for step I is 4–20 hours; The temperature of the calcination I is 450–600°C; The roasting time for step I is 2 to 10 hours; The temperature for hydrogen reduction is 400–550°C; The hydrogen reduction time is 1 to 10 hours.

3. The method according to claim 1, characterized in that, The carrier is obtained through the following steps: The modified molecular sieve, amorphous silicon-containing compound precursor, amorphous aluminum-containing compound precursor, amorphous zirconium-containing compound precursor, organic acid, additives and water are mixed, kneaded, extruded into strips, dried (II), and calcined (II) to obtain the carrier. The amorphous silicon-containing compound precursor is selected from at least one of silica, silica sol, and calcium silicate; The amorphous aluminum-containing compound precursor is selected from at least one of aluminosilicate, kaolin, diatomite, and pseudoboehmite; The amorphous zirconium-containing compound precursor is selected from at least one of zirconium oxide, zirconium sol and zirconium phosphate; The organic acid is selected from at least one of acetic acid, citric acid, acrylic acid, propionic acid, salicylic acid, and tartaric acid; The additive is selected from at least one of carbon black, starch, stearic acid, guar gum, polyvinyl alcohol, polyethylene glycol, dodecyl phosphate, sodium dodecyl sulfonate, and benzalkonium chloride palmitate.

4. The method according to claim 3, characterized in that, The mass ratio of the modified molecular sieve, amorphous silicon-containing compound precursor, amorphous aluminum-containing compound precursor, amorphous zirconium-containing compound precursor, organic acid, and auxiliaries is 5–9:2–4:2–4:0.5–2:0.3–0.6:

1. The temperature of the drying II process is 100–150°C; The drying time for step II is 4–20 hours; The temperature of the second roasting step is 500–700°C; The roasting time for the second stage is 2 to 10 hours.

5. The method according to claim 3, characterized in that, The modified molecular sieve is obtained through the following steps: Sodium-type molecular sieves are immersed in a modified solution for ion modification, then washed with water, dried (III), calcined (III), and treated with high-temperature ammonia to obtain the modified molecular sieves. The sodium-type molecular sieve is selected from at least one of type A molecular sieve, type X molecular sieve, and type L molecular sieve; The modified solution contains a lithium source and / or a beryllium source; The lithium source is selected from at least one of lithium nitrate and lithium chloride; The beryllium source is selected from at least one of beryllium nitrate and beryllium chloride; The concentration of metal ions in the modified solution is 0.3–1.0 mol / L.

6. The method according to claim 5, characterized in that, The temperature for ion modification is 60–80°C; The ion modification time is 1–8 hours; The liquid-to-solid ratio of the ion-modified solution is 6–12:1 mL / g; The temperature of the drying III process is 100–150°C; The drying time for step III is 4–20 hours; The temperature of calcination III is 400–600°C; The roasting time for III is 2–10 hours; The temperature for the high-temperature ammonia treatment is 500–700°C; The high-temperature ammonia treatment time is 1–8 hours; The atmosphere for the high-temperature ammonia treatment is a 10-20 wt% ammonia atmosphere, with the remainder being inert gases.

7. The method according to claim 1, characterized in that, The reactor is selected from at least one of fixed bed, fluidized bed and moving bed.

8. The method according to claim 1, characterized in that, The mass hourly space velocity (MSV) of the acetonitrile is 0.1–10 h⁻¹. -1 ; The molar ratio of hydrogen to acetonitrile is 2 to 8:1; The reaction temperature is 100–250°C; The reaction pressure is 0.1–2.0 MPa.

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