Method for producing monoethylamine

Abstract

The invention relates to the field of monoethylamine preparation processes, and discloses a monoethylamine production method, which comprises: under the action of an ammonolysis catalyst, uniformly mixing and preheating diethylamine, hydrogen and ammonia gas, allowing diethylamine to pass through an ammonolysis reactor and a deamination tower, carrying out monoethylamine refining, diethylamine refining and triethylamine refining, and preparing monoethylamine, the ammonolysis catalyst comprises a carrier as well as an active component and an auxiliary agent which are loaded on the carrier, and is characterized in that the carrier is aluminum oxide modified by a titanium silicalite molecular sieve, the content of the aluminum oxide exceeds 68wt% of the total mass of the carrier, the active component comprises nickel, the auxiliary agent comprises iridium, and the content of the titanium silicalite molecular sieve is more than 68wt% of the total mass of the carrier. On the basis of the total weight of the ammonolysis catalyst, the content of the nickel element is 15-30 wt%, and the content of the iridium element is 0.2-2 wt%. By adopting the method disclosed by the invention, monoethylamine can be directly produced by taking diethylamine as a raw material.

Description

Technical Field

[0001] This invention relates to the field of monoethylamine preparation technology, specifically to a method for producing monoethylamine. Background Technology

[0002] Amines are products in which one or more hydrogen atoms in an ammonia molecule are replaced by hydrocarbon groups. Based on the number of hydrogen atoms replaced in the amine molecule, amines can be classified into primary amines, secondary amines, and tertiary amines. Amines are widely found in the biological world and have extremely important physiological and biological activities. For example, proteins, nucleic acids, many hormones, antibiotics, and alkaloids are all derivatives of amines. Most drugs used clinically are also amines or amine derivatives.

[0003] Ethylamine, also known as aminoethane, is a colorless, flammable, volatile liquid with an ammonia odor. It is miscible with water, alcohols, and ethers in any proportion and is used in the manufacture of dyes, rubber accelerators, extractants, emulsifiers, insecticides, herbicides, and mineral processing agents. It is also widely used in the production of dyes, surfactants, antioxidants, and preservatives, and can be used to manufacture pesticides such as simazine and atrazine.

[0004] Currently, the main methods for synthesizing monoethylamine include ethylene ammoniation, ethane chlorohydrinolysis, acetonitrile hydrogenation, acetaldehyde ammoniation, and ethanol hydroammoniation. The ethane chlorohydrinolysis method for producing monoethylamine produces hydrogen chloride as a byproduct, resulting in low raw material utilization and generating large amounts of chlorine-containing wastewater and salts, causing severe equipment corrosion and environmental pollution; this process has been phased out. The acetonitrile reduction method uses acetonitrile as a raw material and ammonia borane or hydrogen as a hydrogen source, producing monoethylamine through liquid-phase hydrogenation reduction under the action of metal oxides or Raney nickel catalysts. However, due to the high price of acetonitrile, its use is limited, making large-scale production difficult.

[0005] Compared to other production methods, the hydroammoniation of ethanol is more economical due to the inexpensive and readily available ethanol raw materials and the relatively safe and environmentally friendly overall reaction process. Currently, this method is almost universally used in China for the production of ethylamine products. The catalysts commonly used in this process are supported catalysts such as nickel and cobalt. These catalysts are mostly balanced catalysts with good catalytic performance. Therefore, the hydroammoniation process results in a relatively fixed ratio of various ethylamine products in the reaction products, with a yield ratio of approximately 2:5:3, and a relatively high yield of diethylamine. However, the market demand for monoethylamine, diethylamine, and triethylamine differs, with relatively higher demand for monoethylamine and triethylamine. The excess diethylamine produced needs to be separated and returned to the reactor inlet to mix with fresh material before being recycled back into the alcohol amination reactor in large quantities to adjust the product ratio.

[0006] CN112691677 discloses a catalyst for the production of ethylamine by hydroammoniation of ethanol and its application. Data from Example 14 shows that the product contains monoethylamine, diethylamine and triethylamine, and the proportion of diethylamine in the product is as high as 50% or more, while the proportion of monoethylamine in the product is only 16-17%.

[0007] CN114315593 discloses a method for producing ethylamine with an adjustable product ratio. This method utilizes diethylamine produced from the diethylamine product to further react with ethanol, ammonia, etc., to produce triethylamine, thus achieving an adjustable ethylamine product ratio. However, this method of extensively recycling diethylamine products significantly increases the overall energy consumption of the equipment, reduces production efficiency, and generates more byproducts, increasing economic and environmental pressures.

[0008] Therefore, developing a method for directly producing monoethylamine from diethylamine has significant economic and practical implications. Summary of the Invention

[0009] The purpose of this invention is to overcome the problem of low efficiency in the preparation of monoethylamine in the prior art, and to provide a method for producing monoethylamine. Using the method of this invention, monoethylamine can be directly produced from diethylamine as a raw material.

[0010] To achieve the above objectives, the present invention provides a method for producing monoethylamine, wherein the method comprises: mixing and preheating diethylamine, hydrogen and ammonia under the action of an ammonolysis catalyst, and then passing the diethylamine through an ammonolysis reactor, a deammoniation tower, monoethylamine purification, diethylamine purification and triethylamine purification to prepare monoethylamine;

[0011] The ammonium hydrolysis catalyst comprises a support and an active component and an additive loaded on the support. The support is alumina modified with titanium silicate molecular sieves, wherein the alumina content exceeds 68 wt% of the total support mass. The active component includes nickel, and the additive includes iridium. Based on the total weight of the ammonium hydrolysis catalyst, the nickel content is 15-30 wt%, and the iridium content is 0.2-2 wt%.

[0012] Based on the above technical solution, the inventors have proposed a method for directly producing monoethylamine from diethylamine. Specifically, the method involves producing monoethylamine from diethylamine through an ammonolysis reaction in the presence of hydrogen and ammonia via an ammonolysis catalyst bed. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] As mentioned above, the present invention provides a method for producing monoethylamine, wherein the method comprises: mixing and preheating diethylamine, hydrogen and ammonia under the action of an ammonolysis catalyst, and then passing the diethylamine through an ammonolysis reactor, a deammoniation tower, monoethylamine purification, diethylamine purification and triethylamine purification to prepare monoethylamine;

[0015] The ammonium hydrolysis catalyst comprises a support and an active component and an additive loaded on the support. The support is alumina modified with titanium silicate molecular sieves, wherein the alumina content exceeds 68 wt% of the total support mass. The active component includes nickel, and the additive includes iridium. Based on the total weight of the ammonium hydrolysis catalyst, the nickel content is 15-30 wt%, and the iridium content is 0.2-2 wt%.

[0016] According to the present invention, the conditions for the ammonolysis reaction of diethylamine in an ammonolysis reactor include: a reaction pressure of 1-15 MPa and a reaction temperature of 130-200°C; preferably, a reaction pressure of 3-10 MPa and a reaction temperature of 140-180°C; more preferably, a reaction pressure of 4-10 MPa and a reaction temperature of 150-175°C.

[0017] According to the present invention, the feed liquid hourly space velocity of diethylamine is 0.01 m / s. 3 / (m 3 ·h)–1m 3 / (m 3 •h); Preferably, the feed liquid hourly space velocity of diethylamine is 0.1 m / s. 3 / (m 3 ·h)–0.6m 3 / (m 3 More preferably, the feed liquid hourly space velocity of diethylamine is 0.2 m / s; h); 3 / (m 3 ·h)–0.5m 3 / (m 3 ·h).

[0018] According to the present invention, the molar ratio of hydrogen: liquid ammonia: diethylamine is (1-10):(1-50):1; preferably, the molar ratio of hydrogen: liquid ammonia: diethylamine is (3-8):(6-30):1; more preferably, the molar ratio of hydrogen: liquid ammonia: diethylamine is (3-8):(20-30):1.

[0019] According to the present invention, the top temperature of the deammoniation tower is 20-30℃ and the top pressure is 0.8-1.2MPa; in the present invention, the theoretical number of trays of the deammoniation tower is 40-60, and the feed inlet is located in the middle and lower part; preferably, the top temperature of the deammoniation tower is 21-29℃ and the top pressure is 0.9-1.1MPa; the theoretical number of trays of the deammoniation tower is 49-58, and the feed inlet is located on the 27th-33rd tray.

[0020] According to the present invention, the top temperature of the monoethylamine refining column is 20-50℃, and the top pressure is 0.1-0.4MPa; in the present invention, the theoretical number of trays of the monoethylamine refining column is 40-65, and the feed inlet is located in the lower middle part; preferably, the top temperature of the monoethylamine refining column is 26.7-49℃, and the top pressure is 0.15-0.3MPa; the theoretical number of trays of the monoethylamine refining column is 48-62, and the feed inlet is located on the 27th-36th tray.

[0021] According to the present invention, the top temperature of the diethylamine refining column is 75-105℃, and the top pressure is 0.1-0.4MPa; in the present invention, the theoretical number of trays of the diethylamine refining column is 50-65, and the feed inlet is located in the lower middle part; preferably, the top temperature of the diethylamine refining column is 76-102℃, and the top pressure is 0.2-0.4MPa; the theoretical number of trays of the diethylamine refining column is 52-63, and the feed inlet is located on the 29th-35th tray.

[0022] In this invention, those skilled in the art can reasonably and appropriately select the reflux ratio and the ratio of the top product to the feed rate based on the crude product of the reaction and the feed of each distillation column, as well as the purpose of separation and purification. They can also modify the technical solution of this invention based on the various technical teachings given in this invention.

[0023] According to the present invention, the top temperature of the triethylamine refining column is 85-110℃, and the top pressure is 0.1-0.3MPa; in the present invention, the theoretical number of trays of the triethylamine refining column is 50-70, and the feed inlet is located in the lower middle part; preferably, the top temperature of the triethylamine refining column is 88.7-105.6℃, and the top pressure is 0.12-0.25MPa; the theoretical number of trays of the triethylamine refining column is 55-66, and the feed inlet is located on the 29th-36th tray.

[0024] According to the present invention, preferably, the ammonolysis catalyst is a heterogeneous supported catalyst containing nickel and iridium. Based on the mass percentage content of the catalyst, the nickel content is 15-30 wt%, the iridium content is 0.2-2.0 wt%, and the remainder is a support oxide; preferably, based on the total weight of the ammonolysis catalyst, the nickel content is 18-28 wt% and the iridium content is 0.4-1.8 wt%; more preferably, based on the total weight of the ammonolysis catalyst, the nickel content is 18.6-26.8 wt% and the iridium content is 0.45-1.62 wt%.

[0025] Preferably, the carrier oxide is alumina modified with titanium silicate molecular sieve, and the alumina content exceeds 68 wt% of the total carrier mass. In a more preferred case, the alumina content is 75-95 wt% of the total carrier mass, and more preferably 78.8-94.7 wt%.

[0026] Preferably, the alumina content, based on the mass percentage of the carrier, exceeds 75 wt%. The alumina carrier itself possesses certain acidic and basic sites, and its specific properties vary depending on the production method, calcination, and processing of the carrier raw material. Furthermore, the inventors have discovered that other substances can be artificially added to modify the alumina carrier, such as adding SiO2, Al2O3, molecular sieves, zeolites, and acid-base precursors to improve certain carrier properties. In the technical solution of this invention, the carrier can also be treated with fluorine-containing compounds, phosphorus-containing compounds, sulfur-containing compounds, or selenium-containing compounds. These compounds are added during the carrier forming process or catalyst forming process for modification. Alternatively, these compounds or other forms of the corresponding elements can be introduced during the production of the carrier raw material. Through research, the inventors have found that adding an appropriate amount of titanium-silicon molecular sieve helps improve the pore structure and surface physicochemical properties of the carrier, thereby increasing the yield of monoethylamine. Preferably, the Si / Ti molar ratio is 25-40, the grain size is 0.2-0.5 μm, and the sodium content is ≤0.01 wt%. These methods of modifying carriers are merely illustrative and are not limited thereto.

[0027] The shape and size of the catalyst of the present invention can be customized arbitrarily, such as spherical, strip, columnar, ring, etc., with the size mostly between 0.3-6 mm, more preferably between 0.5-4 mm. This size requirement is mainly based on the fixed bed reactor design of the present invention to facilitate installation, reduce bed pressure, and other requirements.

[0028] There are no restrictions on the preparation method of the catalyst; the specific operations in the preparation process can be determined according to the loading of each component of the catalyst. Methods include impregnation, ion exchange, blending, kneading, co-precipitation, deposition-precipitation, ammonium evaporation precipitation, melt-filtration, ball milling, and sol-gel methods. More preferred methods include one or more combinations of impregnation, co-precipitation, and sol-gel methods. These catalyst preparation methods are mostly well-known to those skilled in the art as existing mature technologies. For example, when using spray impregnation to prepare the catalyst, the active and auxiliary components to be loaded on the support are preferably used in the form of soluble salt solutions of those components. The impregnation of the support with metal salt solution can be carried out in any desired order, or it can be carried out continuously with a solution containing one or more metal salts. An appropriate concentration of the solution is selected to load the active metal, etc., onto the support. The impregnated support needs to be dried at a certain temperature, preferably 100-150°C. The required drying time can be set according to the temperature, material quantity, and equipment performance, ensuring that the water content in the dried support does not affect subsequent calcination. The dried catalyst precursor needs to be calcined at a certain temperature to remove the water of crystallization from the salt or to decompose the salt of the desired loading component into oxides. The preferred calcination temperature is 300-500℃. For multiple spray impregnations, it is best to perform drying and calcination after each impregnation. Alternatively, catalyst powder can be prepared by co-precipitation, then dried, decomposed, and then subjected to granulation, tableting, and reduction steps to obtain the desired catalyst product.

[0029] The resulting oxidized catalyst requires reduction to acquire catalytic activity. The optimal reduction temperature is 400-550℃. The gas used for reduction can be pure hydrogen or a mixture, such as a mixture of hydrogen and nitrogen. During reduction, the temperature can be gradually increased, but the increase should not be too rapid, for example, not exceeding 20℃ / hour. Other methods can also be used to reduce the catalyst, such as in-situ irradiation reduction and infrared in-situ reduction.

[0030] Those skilled in the art will be inspired by the above detailed description and can make various modifications to the catalyst support and preparation method of the present invention. For example, any known catalyst, catalyst support, or modified catalyst support and catalyst preparation method can be used.

[0031] According to the present invention, the method further includes:

[0032] (1) Ammonolysis reaction: Diethylamine, recycled material, hydrogen and ammonia are mixed, preheated and then fed into the ammonolysis reactor. Under the action of the ammonolysis catalyst, a crude product containing monoethylamine is obtained. The mixed product from the ammonolysis reactor is cooled and separated into crude monoethylamine product and gas containing hydrogen after gas-liquid separation. The gas is recycled.

[0033] (2) Deamination: The crude product containing at least part of monoethylamine is sent to a deamination tower to separate it into a top product containing liquid ammonia and a bottom product containing monoethylamine.

[0034] (3) Monoethylamine purification: The product in the bottom of the deammoniation tower containing monoethylamine is sent to the monoethylamine purification tower to separate the monoethylamine product at the top of the tower and the product in the bottom of the tower containing diethylamine.

[0035] (4) Diethylamine purification: The product from the bottom of the monoethylamine purification tower containing diethylamine is sent to the diethylamine purification tower to separate the unreacted diethylamine at the top of the tower and the product from the bottom of the tower containing triethylamine.

[0036] (5) Triethylamine purification: The product from the bottom of the diethylamine purification tower containing triethylamine is sent to the triethylamine purification tower to separate the triethylamine product at the top of the tower and the heavy component at the bottom of the tower.

[0037] According to the present invention, the circulating material comes from the top product of the deammoniation tower containing liquid ammonia, the unreacted diethylamine at the top of the diethylamine refining tower, and the hydrogen separated from the gas-liquid separator after the ammonolysis reactor.

[0038] The present invention will be described in detail below through embodiments.

[0039] In the following examples and comparative examples:

[0040] The mass content of each element in the catalyst was determined by X-ray fluorescence spectrometry; the titanium-silicon molecular sieve raw material was a commercially available product of Jiangsu Xianfeng Nanotechnology Co., Ltd., brand name TS-1 (Si / Al molar ratio of 30, grain size of 0.2-0.5 μm, sodium content of 0.007 wt%), and the pseudoboehmite was ordinary pseudoboehmite (specific surface area greater than 280 m²) produced by Shandong Aluminum Co., Ltd. 2 / g, pore volume greater than 0.85ml / g).

[0041] Example 1

[0042] In this embodiment, the ammonolysis catalyst C-1 has the following specific mass composition: 21.5 wt% nickel, 0.45 wt% iridium, and the balance is a γ-Al2O3 support modified with titanium silicate molecular sieve, wherein the Al2O3 content is 78.8 wt% of the total support. The catalyst is prepared by an equal volume impregnation method.

[0043] The method for producing monoethylamine includes the following steps:

[0044] (1) Ammonolysis reaction: Diethylamine, hydrogen, and ammonia are mixed, preheated, and then introduced into an ammonolysis reactor. Under the action of an ammonolysis catalyst, a crude product containing monoethylamine is obtained. The specific reaction conditions are: reaction pressure 4.0 MPa, reaction temperature 155℃, and liquid hourly space velocity of diethylamine 0.3 m / s.3 / (m 3 •h), the molar ratio of diethylamine:hydrogen:liquid ammonia is 1:3:25;

[0045] (2) Deammoniation: The crude product containing at least a portion of monoethylamine is sent to the deammoniation tower to separate it into a top product containing liquid ammonia and a bottom product containing monoethylamine; the theoretical number of trays of the deammoniation tower is 52, the feed inlet is located on the 29th tray, the top temperature is 21.1℃, and the top pressure is 0.9MPa.

[0046] (3) Monoethylamine purification: The product in the bottom of the deammoniation tower containing monoethylamine is sent to the monoethylamine purification tower to separate the monoethylamine product at the top of the tower and the product in the bottom of the tower containing diethylamine; the monoethylamine purification tower has a theoretical number of 60 plates, the feed inlet is located on the 36th plate, the temperature at the top of the tower is 49.1℃, and the pressure at the top of the tower is 0.32MPa;

[0047] (4) Diethylamine refining: The product from the bottom of the monoethylamine refining tower containing diethylamine is sent to the diethylamine refining tower to separate diethylamine at the top of the tower and the product from the bottom of the tower containing triethylamine; the theoretical number of plates of the diethylamine refining tower is 60, the feed inlet is located on the 32nd plate, the temperature at the top of the tower is 84.2℃, and the pressure at the top of the tower is 0.25MPa;

[0048] (5) Triethylamine Refining: The product from the bottom of the diethylamine refining column containing triethylamine is sent to the triethylamine refining column to separate the triethylamine product at the top of the column and the heavy components at the bottom. The theoretical number of trays in the triethylamine refining column is 62, the feed inlet is located on the 35th tray, the top temperature is 88.7℃, and the top pressure is 0.12MPa. The analytical results of each step are shown in Table 1 below.

[0049] Table 1

[0050]

[0051]

[0052] Example 2

[0053] In this embodiment, the ammonolysis catalyst C-2 has the following specific mass content composition: 25.2 wt% nickel, 1.04 wt% iridium, and the balance is a γ-Al2O3 support modified with titanium silicate molecular sieve, wherein the Al2O3 content is 91.3 wt% of the total support. The catalyst is prepared by an equal volume impregnation method.

[0054] The method for producing monoethylamine includes the following steps:

[0055] (1) Ammonolysis reaction: Diethylamine, hydrogen, and ammonia are mixed, preheated, and then introduced into an ammonolysis reactor. Under the action of an ammonolysis catalyst, a crude product containing monoethylamine is obtained. The specific reaction conditions are: reaction pressure 8.0 MPa, reaction temperature 160℃, and liquid hourly space velocity of diethylamine 0.3 m / s. 3 / (m 3 •h), the molar ratio of diethylamine:hydrogen:liquid ammonia is 1:8:20;

[0056] (2) Deammoniation: The crude product containing at least a portion of monoethylamine is sent to the deammoniation tower to separate it into a top product containing liquid ammonia and a bottom product containing monoethylamine; the theoretical number of trays of the deammoniation tower is 49, the feed inlet is located on the 27th tray, the top temperature is 24.7℃, and the top pressure is 1.0MPa.

[0057] (3) Monoethylamine refining: The product from the deammoniation tower containing monoethylamine is sent to the monoethylamine refining tower to separate the monoethylamine product at the top of the tower and the product from the bottom of the tower containing diethylamine; the monoethylamine refining tower has a theoretical number of 62 plates, the feed inlet is located on the 33rd plate, the temperature at the top of the tower is 33.9℃, and the pressure at the top of the tower is 0.2MPa;

[0058] (4) Diethylamine purification: The product from the bottom of the monoethylamine purification tower containing diethylamine is sent to the diethylamine purification tower to separate diethylamine at the top of the tower and the product from the bottom of the tower containing triethylamine; the theoretical number of plates of the diethylamine purification tower is 63, the feed inlet is located on the 35th plate, the temperature at the top of the tower is 102.3℃, and the pressure at the top of the tower is 0.4MPa;

[0059] (5) Triethylamine Refining: The product from the bottom of the diethylamine refining column containing triethylamine is sent to the triethylamine refining column to separate the triethylamine product at the top of the column and the heavy components at the bottom. The theoretical number of trays in the triethylamine refining column is 55, the feed inlet is located on the 29th tray, the top temperature is 98.7℃, and the top pressure is 0.2MPa. The analytical results of each step are shown in Table 2 below.

[0060] Table 2

[0061]

[0062] Example 3

[0063] In this embodiment, the ammonolysis catalyst C-3 has the following specific mass composition: 18.6 wt% nickel, 1.62 wt% iridium, and the balance is a γ-Al2O3 support modified with titanium-silicon molecular sieve, wherein the Al2O3 content is 82.6 wt% of the total support. The catalyst is prepared by an equal-volume impregnation method.

[0064] The method for producing monoethylamine includes the following steps:

[0065] (1) Ammonolysis reaction: Diethylamine, hydrogen, and ammonia are mixed, preheated, and then introduced into an ammonolysis reactor. Under the action of an ammonolysis catalyst, a crude product containing monoethylamine is obtained. The specific reaction conditions are: reaction pressure 10.0 MPa, reaction temperature 150 °C, and liquid hourly space velocity of diethylamine 0.2 m / s. 3 / (m 3 •h), the molar ratio of diethylamine:hydrogen:liquid ammonia is 1:5:30;

[0066] (2) Deammoniation: The crude product containing at least a portion of monoethylamine is sent to the deammoniation tower to separate it into a top product containing liquid ammonia and a bottom product containing monoethylamine; the theoretical number of trays of the deammoniation tower is 58, the feed inlet is located on the 33rd tray, the top temperature is 25.9℃, and the top pressure is 1.0MPa.

[0067] (3) Monoethylamine purification: The product in the bottom of the deammoniation tower containing monoethylamine is sent to the monoethylamine purification tower to separate the monoethylamine product at the top of the tower and the product in the bottom of the tower containing diethylamine; the monoethylamine purification tower has a theoretical number of 48 plates, the feed inlet is located on the 27th plate, the temperature at the top of the tower is 26.7℃, and the pressure at the top of the tower is 0.15MPa;

[0068] (4) Diethylamine purification: The product from the bottom of the monoethylamine purification tower containing diethylamine is sent to the diethylamine purification tower to separate diethylamine at the top of the tower and the product from the bottom of the tower containing triethylamine; the theoretical number of plates of the diethylamine purification tower is 52, the feed inlet is located on the 29th plate, the temperature at the top of the tower is 76.2℃, and the pressure at the top of the tower is 0.2MPa;

[0069] (5) Triethylamine Refining: The product from the bottom of the diethylamine refining column containing triethylamine is sent to the triethylamine refining column to separate the triethylamine product at the top of the column and the heavy components at the bottom. The theoretical number of trays for the triethylamine refining column is 66, the feed inlet is located on the 36th tray, the top temperature is 92.9℃, and the top pressure is 0.15MPa. The analytical results of each step are shown in Table 3 below.

[0070] Table 3

[0071]

[0072] Example 4

[0073] In this embodiment, the ammonolysis catalyst C-4 has the following specific mass composition: 26.8 wt% nickel, 0.83 wt% iridium, and the balance is a γ-Al2O3 support modified with titanium silicate molecular sieve, wherein the Al2O3 content is 86.1 wt% of the total support. The catalyst is prepared by an equal volume impregnation method.

[0074] The method for producing monoethylamine includes the following steps:

[0075] (1) Ammonolysis reaction: Diethylamine, hydrogen, and ammonia are mixed, preheated, and then introduced into an ammonolysis reactor. Under the action of an ammonolysis catalyst, a crude product containing monoethylamine is obtained. The specific reaction conditions are: reaction pressure 4.0 MPa, reaction temperature 175℃, and liquid hourly space velocity of diethylamine 0.5 m / s. 3 / (m 3 •h), the molar ratio of diethylamine:hydrogen:liquid ammonia is 1:5:25;

[0076] (2) Deammoniation: The crude product containing at least a portion of monoethylamine is sent to the deammoniation tower to separate it into a top product containing liquid ammonia and a bottom product containing monoethylamine; the theoretical number of trays of the deammoniation tower is 52, the feed inlet is located on the 28th tray, the top temperature is 29.3℃, and the top pressure is 1.1MPa.

[0077] (3) Monoethylamine refining: The product from the deammoniation tower containing monoethylamine is sent to the monoethylamine refining tower to separate the monoethylamine product at the top of the tower and the product from the bottom of the tower containing diethylamine; the monoethylamine refining tower has a theoretical number of 55 plates, the feed inlet is located on the 30th plate, the temperature at the top of the tower is 40.5℃, and the pressure at the top of the tower is 0.25MPa;

[0078] (4) Diethylamine purification: The product from the bottom of the monoethylamine purification tower containing diethylamine is sent to the diethylamine purification tower to separate diethylamine at the top of the tower and the product from the bottom of the tower containing triethylamine; the theoretical number of plates of the diethylamine purification tower is 55, the feed inlet is located on the 30th plate, the temperature at the top of the tower is 92.4℃, and the pressure at the top of the tower is 0.31MPa;

[0079] (5) Triethylamine Refining: The product from the bottom of the diethylamine refining column containing triethylamine is sent to the triethylamine refining column to separate the triethylamine product at the top of the column and the heavy components at the bottom. The theoretical number of trays for the triethylamine refining column is 58, the feed inlet is located on the 31st tray, the top temperature is 105.6℃, and the top pressure is 0.25MPa. The analytical results of each step are shown in Table 4 below.

[0080] Table 4

[0081]

[0082] Example 5

[0083] In this embodiment, the ammonolysis catalyst C-5 has the following specific mass composition: 22.4 wt% nickel, 0.75 wt% iridium, and the balance is a γ-Al2O3 support modified with titanium-silicon molecular sieve, wherein the Al2O3 content is 94.7 wt% of the total support. The catalyst is prepared by an equal volume impregnation method.

[0084] Comparative Example 1

[0085] In this embodiment, the ammonolysis catalyst B-1 has the following specific mass composition: 20.6 wt% nickel, 1.35 wt% iridium, and the balance being a γ-Al2O3 support modified with titanium silicate molecular sieve, wherein the Al2O3 content is 65.9 wt% of the total support. The catalyst is prepared by an equal volume impregnation method.

[0086] Comparative Example 2

[0087] In this embodiment, the ammonolysis catalyst B-2 has the following specific mass content composition: 13.9 wt% nickel, 0.59 wt% iridium, and the balance is a γ-Al2O3 support modified with titanium silicate molecular sieve, wherein the Al2O3 content is 80.8 wt% of the total support. The catalyst is prepared by an equal volume impregnation method.

[0088] Comparative Example 3

[0089] In this embodiment, the ammonolysis catalyst B-3 has the following specific mass composition: 32.7 wt% nickel, 1.76 wt% iridium, and the balance being a γ-Al2O3 support modified with titanium silicate molecular sieve, wherein the Al2O3 content is 91.6 wt% of the total support. The catalyst is prepared by an equal volume impregnation method.

[0090] Example 6

[0091] This embodiment illustrates the use of the ammonolysis catalyst prepared above for the ammonolysis of diethylamine to prepare monoethylamine.

[0092] 100 mL of catalysts C-1 to C-5 and B-1 to B-3 were each measured and placed in the ammonolysis reactor. The reactor was activated with hydrogen at 260°C for 2 hours, then cooled to 160°C. The system pressure was increased to 5.5 MPa using hydrogen. Ammonia, after preheating and mixing with hydrogen, was then metered into the reactor using a metering pump. Diethylamine was also metered into the reactor. The three reacted through the catalyst bed under the following conditions: a molar ratio of diethylamine:hydrogen:liquid ammonia of 1:5:20, and a liquid hourly space velocity (LHSV) of 0.3 h⁻¹. -1 After the reaction stabilized, samples were taken for analysis. The reaction results are shown in Table 5.

[0093] Table 5

[0094]

[0095] The results above demonstrate that the method of this invention can efficiently produce monoethylamine.

[0096] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for producing monoethylamine, characterized in that, The method includes: mixing and preheating diethylamine, hydrogen and ammonia under the action of an ammonolysis catalyst, and then passing the diethylamine through an ammonolysis reactor, a deammoniation tower, a monoethylamine purification process, a diethylamine purification process and a triethylamine purification process to prepare monoethylamine; The ammonium hydrolysis catalyst comprises a support and an active component and an additive loaded on the support. The support is alumina modified with titanium silicate molecular sieves, wherein the alumina content exceeds 68 wt% of the total support mass. The active component includes nickel, and the additive includes iridium. Based on the total weight of the ammonium hydrolysis catalyst, the nickel content is 15-30 wt%, and the iridium content is 0.2-2 wt%.

2. The method according to claim 1, wherein, The conditions for the ammonolysis reaction of diethylamine in an ammonolysis reactor include: reaction pressure 1-15 MPa and reaction temperature 130-200℃; And / or, the feed liquid hourly space velocity for diethylamine is 0.01 m³ / s. 3 / (m 3 ·h)–1m 3 / (m 3 ·h); And / or, the molar ratio of hydrogen: liquid ammonia: diethylamine is (1-10):(1-50):

1.

3. The method according to claim 2, wherein, The conditions for the ammonolysis reaction of diethylamine in an ammonolysis reactor include: reaction pressure 3-10 MPa and reaction temperature 140-180℃; And / or, the feed liquid hourly space velocity for diethylamine is 0.1 m³ / s. 3 / (m 3 ·h)–0.6m 3 / (m 3 ·h); And / or, the molar ratio of hydrogen: liquid ammonia: diethylamine is (3-8):(6-30):

1.

4. The method according to claim 1, wherein, The temperature at the top of the deammoniation tower is 20-30℃, and the pressure at the top of the tower is 0.8-1.2MPa.

5. The method according to claim 1, wherein, The top temperature of the monoethylamine refining column is 20-50℃, and the top pressure is 0.1-0.4MPa. And / or, the top temperature of the diethylamine refining column is 75-105℃, and the top pressure is 0.1-0.4MPa; And / or, the top temperature of the triethylamine refining column is 85-110℃, and the top pressure is 0.1-0.3MPa.

6. The method according to claim 1, wherein, The alumina content in the carrier exceeds 75 wt% of the total carrier mass.

7. The method according to claim 1 or 6, wherein, Based on the total weight of the ammonolysis catalyst, the nickel content is 18-27 wt% and the iridium content is 0.5-1.5 wt%.

8. The method according to any one of claims 1-7, wherein, The SiO2 / TiO2 ratio of the titanium-silicon molecular sieve is 25-40, the grain size is 0.2-0.5μm, and the sodium content is ≤0.01wt%.

9. The method according to any one of claims 1-8, wherein, The method further includes: (1) Ammonolysis reaction: Diethylamine, recycled material, hydrogen and ammonia are mixed, preheated and then fed into the ammonolysis reactor. Under the action of the ammonolysis catalyst, a crude product containing monoethylamine is obtained. The mixed product from the ammonolysis reactor is cooled and separated into crude monoethylamine product and gas containing hydrogen after gas-liquid separation. The gas is recycled. (2) Deamination: The crude product containing at least part of monoethylamine is sent to a deamination tower to separate it into a top product containing liquid ammonia and a bottom product containing monoethylamine. (3) Monoethylamine purification: The product in the bottom of the deammoniation tower containing monoethylamine is sent to the monoethylamine purification tower to separate the monoethylamine product at the top of the tower and the product in the bottom of the tower containing diethylamine. (4) Diethylamine purification: The product from the bottom of the monoethylamine purification tower containing diethylamine is sent to the diethylamine purification tower to separate the unreacted diethylamine at the top of the tower and the product from the bottom of the tower containing triethylamine. (5) Triethylamine purification: The product from the bottom of the diethylamine purification tower containing triethylamine is sent to the triethylamine purification tower to separate the triethylamine product at the top of the tower and the heavy component at the bottom of the tower.

10. The method according to claim 9, wherein, The circulating materials come from the top product of the deammoniation tower containing liquid ammonia, the unreacted diethylamine at the top of the diethylamine refining tower, and the hydrogen separated from the gas-liquid separator after the ammonolysis reactor.

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