CN-121990925-A - Method for co-production of monoethylamine and acetonitrile

CN121990925ACN 121990925 ACN121990925 ACN 121990925ACN-121990925-A

Abstract

The invention relates to the technical field of production of monoethylamine and acetonitrile and refining separation thereof by using ethylenediamine, and discloses a method for Co-production of monoethylamine and acetonitrile, which comprises the steps of (S1) under the condition of a catalyst, uniformly mixing and preheating diethylamine, hydrogen and ammonia, reacting by an ammonolysis reactor and separating gas from liquid, then separating a crude product into a monoethylamine product at the top of the tower and a tower kettle product containing diethylamine and acetonitrile by a monoethylamine refining tower, wherein the catalyst comprises alumina modified by a SAPO-34 molecular sieve, ni, co, pr and/or Nd, the Ni and Co are 15-40wt%, and the mole ratio of Ni/Co is 1-8.5, and (S2) separating the tower kettle product containing diethylamine and acetonitrile which is led out by the monoethylamine refining tower into a solvent-containing material flow at the top of the tower and the acetonitrile product at the tower kettle by the acetonitrile refining tower, and simultaneously producing the monoethylamine and the acetonitrile product by rectifying separation.

Inventors

TANG GUOQI
TIAN BAOLIANG
FU SIXIAN
NIU SHU
SU ZIMU
CAI MAO

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. A process for co-producing monoethylamine and acetonitrile, said process comprising: Under the action of a supported catalyst, uniformly mixing and preheating diethylamine, hydrogen and ammonia, reacting by an ammonolysis reactor, and separating gas-liquid separated crude products into a monoethylamine product at the top of the tower and a tower kettle product containing diethylamine and acetonitrile; The supported catalyst comprises a carrier, an active component and an auxiliary agent, wherein the active component and the auxiliary agent are supported on the carrier, the carrier is alumina modified by a SAPO-34 molecular sieve, the active component is Ni and Co, the auxiliary agent is Pr and/or Nd, the total content of Ni and Co elements is 15-40wt% based on the total weight of the supported catalyst, and the molar ratio of Ni/Co is 1-8.5; (S2) separating the tower bottom product containing diethylamine and acetonitrile, which is led out from the monoethylamine refining tower, into a solvent-containing material flow at the tower top and an acetonitrile product at the tower bottom through the acetonitrile refining tower.
2. The process according to claim 1, wherein the monoethylamine refining column has a top temperature of 10-30 ℃ and a top pressure of 0.05-0.2MPa.
3. The process according to claim 1 or 2, wherein the acetonitrile refining column has a column top temperature of 60-110 ℃ and a column top pressure of 0.05-0.2MPa.
4. The method according to any one of claims 1 to 3, wherein the conditions for the reaction in the ammonolysis reactor after uniformly mixing and preheating diethylamine, hydrogen and ammonia include a reaction temperature of 180 to 300 ℃ and a reaction pressure of 0.1 to 10MPa; and/or, the feed liquid phase volume space velocity of diethylamine is 0.05m 3 /(m 3 ·h)-1m 3 /(m 3 h); and/or the mol ratio of diethylamine to hydrogen to liquid ammonia is 1 (0.1-5) to 5-100.
5. The method according to claim 1, wherein the total content of Ni and Co elements is 15-40wt% and the molar ratio of Ni/Co is 3-7 based on the total weight of the supported catalyst; preferably, the total content of Ni and Co elements is 20-35wt%, based on the total weight of the supported catalyst.
6. The method of claim 1, wherein the promoter is Nd; And/or, the content of the auxiliary agent is 0.5-3wt% based on the total weight of the supported catalyst.
7. The method of claim 1, wherein the alumina content of the support is 50-90wt% of the total weight of the support; preferably, the alumina content of the support is 60-80wt% of the total weight of the support.
8. The method of claim 1 or 7, wherein SiO 2 /(SiO 2 +Al 2 O 3 +P 2 O 5 ) in the SAPO-34 molecular sieve is 0.09-0.12, grain size is 1-2 μm, specific surface area >600m 2 /g.
9. The method of any one of claims 1-8, wherein the method further comprises: (1) Uniformly mixing diethylamine, hydrogen and ammonia, preheating, introducing the mixture into an ammonolysis reactor, and reacting under the action of a catalyst to obtain a crude product containing monoethylamine and acetonitrile; (2) Deamination, namely separating at least part of crude products containing monoethylamine and acetonitrile after gas-liquid separation into tower top products containing liquid ammonia and tower bottom products containing monoethylamine and acetonitrile through a deamination tower; (3) Refining monoethylamine, namely separating a tower bottom product containing monoethylamine and acetonitrile, which is led out from a deamination tower, into a monoethylamine product at the tower top and a tower bottom product containing diethyl amine and acetonitrile at the tower bottom through a monoethylamine refining tower; (4) Diethyl amine refining, namely separating the tower bottom product containing diethyl amine and acetonitrile, which is led out by a monoethyl amine refining tower, into diethyl amine at the tower top and a tower bottom product containing triethylamine and acetonitrile by a diethyl amine refining tower; (5) The triethylamine refining step, namely, the tower bottom product containing the triethylamine and the acetonitrile, which is led out from a diethylamine refining tower, is processed by the triethylamine refining tower, simultaneously, a solvent is led into the triethylamine refining tower, and the triethylamine product in the Cheng Da tower bottom and the tower top product containing the solvent and the acetonitrile are separated; (6) The tower kettle product containing the solvent and the acetonitrile, which is led out from the triethylamine refining tower, is led into the liquid-liquid layering device, and after layering and enrichment, the material flow with higher solvent concentration on the upper layer is returned to the triethylamine refining tower, and the material flow with higher acetonitrile concentration on the lower layer flows through the subsequent acetonitrile refining tower; (7) And the acetonitrile refining tower is used for separating the material flow with higher acetonitrile concentration into a solvent-containing material flow at the top of the tower and a high-purity acetonitrile product at the bottom of the tower through the acetonitrile refining tower.
10. The process of claim 9, wherein the deamination column has a top temperature of 20-30 ℃ and a top pressure of 0.8-1.2MPa; and/or the temperature of the top of the diethylamine refining tower is 45-70 ℃ and the pressure of the top of the diethylamine refining tower is 0.05-0.2MPa; And/or the temperature of the top of the triethylamine refining tower is 54-65 ℃ and the pressure of the top of the triethylamine refining tower is 0.1-0.3MPa; And/or the operating temperature of the liquid-liquid separator is 50-70 ℃ and the operating pressure is 0.05-0.2MPa.

Description

Method for co-production of monoethylamine and acetonitrile Technical Field The invention relates to the technical field of production of monoethylamine and acetonitrile by using ethylenediamine and refining separation thereof, in particular to a method for co-producing monoethylamine and acetonitrile. Background 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 prepare monoethylamine. However, acetonitrile is expensive, and has limited use, which makes mass production difficult. Compared with other 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 proportion of diethylamine 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. 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 prepare triethylamine, thereby realizing adjustable ethylamine product proportion. However, the method for recycling the diethylamine product in a large quantity greatly improves the whole energy consumption of the device, reduces the production efficiency of the device, and simultaneously generates more byproducts, so that the subsequent separation is difficult, and the economic and environmental protection pressures are increased. Acetonitrile is a fine chemical product with wide application, and can be used as an extractant, a solvent and a raw material for synthesizing pesticides. At present, acetonitrile on the global scale is mainly recovered from crude byproducts of acrylonitrile production by ammoxidation of propylene, and the yield is 2-3% of the acrylonitrile yield, and the yield has instability and is relatively high in the yield of an acrylonitrile device. The new production process of acetonitrile is of great interest. At present, the main production technology of acetonitrile comprises acrylonitrile byproduct recovery, acetic acid ammonification dehydration, ethanol dehydrogenation ammonification, monoethylamine dehydrogenation and the like. The recovery of acrylonitrile by-product has limited productivity, and it is difficult to produce acetonitrile with high purity. The ammonification method is that alumina is used as a catalyst, acetic acid and ammonia are firstly generated into ammonium acetate at a high temperature (370-450 ℃), the ammonium acetate is dehydrated into acetamide, and the acetamide is further dehydrated to prepare acetonitrile. CN11757320 discloses a method for preparing acetonitrile and co-producing acetamide by acetic acid ammonification, which controls the reaction temperature and process to adjust the product to be acetamide or acetonitrile, but the problems of high