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CN-121990926-A - Method for producing monoethylamine

CN121990926ACN 121990926 ACN121990926 ACN 121990926ACN-121990926-A

Abstract

The invention relates to the technical field of preparation of ethylamine and discloses a method for producing monoethylamine, which comprises the steps of uniformly mixing and preheating diethyl amine, hydrogen and ammonia under the action of an ammonolysis catalyst, then carrying out ammonolysis reaction on the diethyl amine, a deamination tower, monoethylamine refining, diethyl amine refining and triethylamine refining to prepare monoethylamine, wherein the ammonolysis catalyst comprises a carrier, and an active component and an auxiliary agent which are loaded on the carrier, and is characterized in that the carrier is alumina modified by a titanium silicalite molecular sieve, wherein the content of the alumina exceeds 68 weight percent of the total mass of the carrier, the active component comprises nickel, the auxiliary agent comprises iridium, the content of nickel element is 15-30 weight percent and the content of iridium element is 0.2-2 weight percent based on the total weight of the ammonolysis catalyst. By adopting the method of the invention, diethylamine can be used as a raw material to directly produce monoethylamine.

Inventors

  • TANG GUOQI
  • TIAN BAOLIANG
  • FU SIXIAN
  • ZHANG LIJUN
  • PENG HUI
  • CAI MAO
  • SU ZIMU
  • NIU SHU

Assignees

  • 中国石油化工股份有限公司
  • 中石化(北京)化工研究院有限公司

Dates

Publication Date
20260508
Application Date
20241104

Claims (10)

  1. 1. A method for producing monoethylamine is characterized by comprising the steps of uniformly mixing and preheating diethyl amine, hydrogen and ammonia under the action of an ammonolysis catalyst, and preparing monoethylamine by the diethyl amine through an ammonolysis reactor, a deamination tower, monoethylamine refining, diethyl amine refining and triethylamine refining; The ammonolysis catalyst comprises a carrier, and an active component and an auxiliary agent which are loaded on the carrier, and is characterized in that the carrier is alumina modified by a titanium-silicon molecular sieve, wherein the content of the alumina exceeds 68wt% of the total weight of the carrier, the active component comprises nickel, the auxiliary agent comprises iridium, the content of nickel element is 15-30wt% and the content of iridium element is 0.2-2wt% based on the total weight of the ammonolysis catalyst.
  2. 2. The method according to claim 1, wherein the conditions for carrying out the ammonolysis reaction of the diethylamine by the ammonolysis reactor comprise a reaction pressure of 1-15MPa and a reaction temperature of 130-200 ℃; And/or, the feed liquid phase volume space velocity of diethylamine is 0.01m 3 /(m 3 ·h)–1m 3 /(m 3 h); and/or the molar ratio of hydrogen to liquid ammonia to diethylamine is (1-10): 1-50): 1.
  3. 3. The method according to claim 2, wherein the conditions for carrying out the ammonolysis reaction of the diethylamine by the ammonolysis reactor comprise a reaction pressure of 3-10MPa and a reaction temperature of 140-180 ℃; And/or, the feed liquid phase volume space velocity of diethylamine is 0.1m 3 /(m 3 ·h)–0.6m 3 /(m 3 h); And/or the molar ratio of hydrogen to liquid ammonia to diethylamine is (3-8): 6-30): 1.
  4. 4. The process of claim 1, wherein the deamination column has a top temperature of 20-30 ℃ and a top pressure of 0.8-1.2MPa.
  5. 5. The method according to claim 1, wherein the temperature of the top of the monoethylamine refining tower is 20-50 ℃, and the pressure of the top of the monoethylamine refining tower is 0.1-0.4 mpa; And/or the tower top temperature of the diethylamine refining tower is 75-105 ℃ and the tower top pressure is 0.1-0.4MPa; And/or the temperature of the top of the triethylamine refining tower is 85-110 ℃, and the pressure of the top of the triethylamine refining tower is 0.1-0.3MPa.
  6. 6. The method of claim 1, wherein the alumina content of the support is greater than 75wt% of the total mass of the support.
  7. 7. The process according to claim 1 or 6, wherein the content of nickel element is 18-27wt% and the content of iridium element is 0.5-1.5wt%, based on the total weight of the ammonolysis catalyst.
  8. 8. The method according to any one of claims 1 to 7, wherein the titanium silicalite molecular sieve has a SiO 2 /TiO 2 ratio of 25 to 40, a grain size of 0.2 to 0.5 μm and a sodium content of 0.01 wt.% or less.
  9. 9. The method of any one of claims 1-8, wherein the method further comprises: (1) The ammonolysis reaction, namely uniformly mixing and preheating diethylamine, circulating materials, hydrogen and ammonia gas, introducing the mixture into an ammonolysis reactor, reacting the mixture under the action of an ammonolysis catalyst to obtain a crude product containing monoethylamine, cooling the mixed product from the ammonolysis reactor, separating the gas from the liquid to obtain a crude monoethylamine product and a gas containing hydrogen, and recycling the gas; (2) Deamination, namely feeding at least part of crude product containing monoethylamine into a deamination tower, and separating the crude product into a tower top product containing liquid ammonia and a tower bottom product containing monoethylamine; (3) Refining monoethylamine, namely sending the tower bottom product of the deamination tower containing monoethylamine to a monoethylamine refining tower, and separating the tower bottom product into a monoethylamine product at the tower top and a tower bottom product containing diethyl amine at the tower bottom; (4) Diethyl amine refining, namely conveying a tower bottom product of the monoethyl amine refining tower containing diethyl amine to a diethyl amine refining tower, and separating the diethyl amine into unreacted diethyl amine at the tower top and a tower bottom product containing triethylamine; (5) And (3) refining triethylamine, namely conveying a product at the tower bottom of the triethylamine refining tower containing triethylamine to a triethylamine refining tower, and separating the product into a triethylamine product at the tower top and heavy components at the tower bottom.
  10. 10. The process of claim 9, wherein the recycle material is from a top product of the deamination column containing liquid ammonia, unreacted diethylamine at the top of the diethylamine purification column, and hydrogen separated from a post-ammonolysis reactor gas-liquid separation tank.

Description

Method for producing monoethylamine Technical Field The invention relates to the technical field of a preparation process of monoethylamine, in particular to a method for producing monoethylamine. Background Amine refers to a product obtained by substituting one or more hydrogen atoms in an ammonia molecule with hydrocarbon groups, and can be divided into primary amine, secondary amine and tertiary amine according to the number of the hydrogen atoms in the amine molecule, wherein the amine is widely existing in the biological world and has extremely important physiological activity and biological activity, such as protein, nucleic acid, a plurality of hormones, antibiotics, alkaloids and the like, and most of clinically used medicaments are also amine or amine derivatives. Monoethylamine, also known as ethylamine, aminoethane, is a colorless liquid, flammable, and volatile with ammonia odor. The water-soluble polymer is arbitrarily mixed with water, alcohol and ether, is used for preparing dyes, rubber accelerators, extractants, emulsifying agents, pesticides, herbicides and mineral processing agents, is also widely used in the production of dyes, surfactants, antioxidants, preservatives and the like, and can also be used for preparing pesticides simazine, atrazine and the like. At present, the synthesis method of monoethylamine mainly comprises an ethylene ammonification method, a chloroethane ammonification method, an acetonitrile hydrogenation method, an acetaldehyde ammonification method, an ethanol hydro-ammonification method and the like. The reaction process for preparing monoethylamine by ammonolysis of chloroethane has the advantages of by-product hydrogen chloride, low raw material utilization rate, and high generation of chlorine-containing waste water and salt, and serious equipment corrosion and environmental pollution. Acetonitrile is used as raw material, ammonia borane or hydrogen is used as hydrogen source, and under the action of metal oxide or Raney nickel catalyst the liquid phase hydrogenation reduction is carried out to produce monoethylamine. However, acetonitrile is expensive, and has limited use, which makes mass production difficult. Compared with other production methods, the ethanol hydro-ammoniation method has the advantages that the ethanol raw material is cheap and easy to obtain, the whole reaction process is relatively safe and environment-friendly, the method has more economical efficiency, and the method is almost adopted to produce ethylamine products in China at present. The catalysts commonly used in the process are supported catalysts such as nickel and cobalt, and the like, and the catalysts are balanced catalysts and have good catalytic reaction performance, so that the hydro-ammoniation process ensures that the proportion of various ethylamine products in the reaction products is relatively fixed, the output proportion is basically 2:5:3, and the diethylamine output proportion is higher. However, the market has different requirements for monoethylamine, diethyl amine and triethylamine, the requirements for monoethylamine and triethylamine are relatively large, and more diethyl amine is produced, and the diethyl amine is required to be separated and then returned to the inlet of the reactor to be mixed with fresh materials and then enters the alcohol ammoniation reactor for a large number of cycles, so that the product proportion is regulated. CN112691677 discloses a catalyst for producing ethylamine by hydro-ammonifying ethanol and its application, and the data of example 14 shows that the product contains products such as monoethylamine, diethyl amine and triethylamine, the proportion of diethyl amine in the product is up to more than 50%, and the proportion of monoethylamine in the product is only 16-17%. CN114315593 discloses a method for producing ethylamine with randomly adjustable product proportion, which uses diethylamine produced in the product to further react with ethanol, ammonia and the like to produce triethylamine, thereby realizing adjustable ethylamine product proportion. However, the method for recycling the diethylamine product in a large amount greatly improves the energy consumption of the whole device, reduces the production efficiency of the device, generates more byproducts and increases the economic and environmental protection pressures. Therefore, the development of a method for directly producing monoethylamine by taking diethyl amine as a raw material has important economic and practical significance. Disclosure of Invention The invention aims to solve the problem of low efficiency of monoethylamine prepared by the prior art, and provides a method for producing monoethylamine. In order to achieve the above object, the present invention provides a method for producing monoethylamine, wherein the method comprises mixing diethyl amine, hydrogen and ammonia under the action of an ammonolysis catalyst, preheating, and preparing monoethylamine