CN115594610A - Method for continuously producing high-purity acetonitrile by micro-channel - Google Patents
Method for continuously producing high-purity acetonitrile by micro-channel Download PDFInfo
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- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 title claims abstract description 303
- 238000000034 method Methods 0.000 title claims abstract description 49
- 238000006243 chemical reaction Methods 0.000 claims abstract description 52
- 239000000463 material Substances 0.000 claims abstract description 31
- 238000001816 cooling Methods 0.000 claims abstract description 15
- 239000012535 impurity Substances 0.000 claims abstract description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 15
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 11
- 230000002378 acidificating effect Effects 0.000 claims abstract description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 75
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 21
- 239000012530 fluid Substances 0.000 claims description 8
- 150000003839 salts Chemical class 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 15
- 230000008569 process Effects 0.000 abstract description 13
- 238000003786 synthesis reaction Methods 0.000 abstract description 12
- 230000015572 biosynthetic process Effects 0.000 abstract description 11
- 238000007086 side reaction Methods 0.000 abstract description 7
- 238000009776 industrial production Methods 0.000 abstract description 4
- 239000002994 raw material Substances 0.000 description 36
- 239000007788 liquid Substances 0.000 description 15
- 239000003054 catalyst Substances 0.000 description 14
- 239000006200 vaporizer Substances 0.000 description 10
- 239000007789 gas Substances 0.000 description 5
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 238000007599 discharging Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 238000001308 synthesis method Methods 0.000 description 4
- 238000006555 catalytic reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- 230000002194 synthesizing effect Effects 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- CHPZKNULDCNCBW-UHFFFAOYSA-N gallium nitrate Chemical compound [Ga+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O CHPZKNULDCNCBW-UHFFFAOYSA-N 0.000 description 2
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 2
- 239000002808 molecular sieve Substances 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000001994 activation Methods 0.000 description 1
- 239000004480 active ingredient Substances 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229960000074 biopharmaceutical Drugs 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 238000007036 catalytic synthesis reaction Methods 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 229910052570 clay Inorganic materials 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 229940044658 gallium nitrate Drugs 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910001960 metal nitrate Inorganic materials 0.000 description 1
- 239000004005 microsphere Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000009740 moulding (composite fabrication) Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/22—Preparation of carboxylic acid nitriles by reaction of ammonia with carboxylic acids with replacement of carboxyl groups by cyano groups
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0093—Microreactors, e.g. miniaturised or microfabricated reactors
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/32—Separation; Purification; Stabilisation; Use of additives
- C07C253/34—Separation; Purification
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a method for continuously producing high-purity acetonitrile by a micro-channel, belonging to the field of acetonitrile synthesis. The method for continuously producing the high-purity acetonitrile by the micro-channel comprises the following steps: preheating, reacting, cooling and rectifying. In the reaction, the temperature of the second microreactor is controlled to be 300-450 ℃, and the preheated mixed material is discharged to a third microreactor after reacting for 120-480s in the second microreactor; the inner wall of the second micro-reactor is made of acidic alumina. The method for continuously producing the high-purity acetonitrile by the micro-channel effectively reduces the occurrence of side reactions in the acetonitrile synthesis process, the prepared acetonitrile synthesis solution contains 50.4-52.6wt% of acetonitrile, 45.0-46.1wt% of water, 0.19-0.27wt% of impurities, 85.5-90.1% of acetonitrile yield, the production system is good in stability and high in production safety, and the micro-channel industrial production of the acetonitrile is realized.
Description
Technical Field
The invention relates to the field of acetonitrile synthesis, in particular to a method for continuously producing high-purity acetonitrile by using a micro-channel.
Background
Acetonitrile is a widely used industrial product, and plays a significant role in the fields of organic synthesis, biopharmaceuticals, electronic chemicals, analytical detection and the like. In the prior art, the synthesis technology of acetonitrile mainly comprises two types: direct synthesis and indirect synthesis. The indirect method is mainly characterized in that acetonitrile is produced as a byproduct during the synthesis of acrylonitrile. The direct synthesis method comprises the following steps: acetic acid ammoniation method and ethanol ammoniation method.
With the continuous requirement of industrial upgrading, the demand of high-purity acetonitrile is gradually increased, and compared with the byproduct acetonitrile of the indirect synthesis method, the acetonitrile prepared by the direct synthesis method has obvious advantages in the aspects of purity, impurity types and the like. Meanwhile, in the direct synthesis method, hydrogen is generated in the process of preparing acetonitrile by adopting an ethanol ammoniation method, so that the method has certain danger. Therefore, the acetic acid ammoniation method becomes the main technical route of industrial acetonitrile production, and the research on the production process and industrial production thereof becomes a hot spot at home and abroad.
The inventor finds that in the existing process for synthesizing acetonitrile by an acetic acid ammoniation method, in order to ensure that better reaction effect and product quality are obtained, a catalyst is required to be used for catalysis in the reaction process, the catalyst usually adopts activated clay, alumina, silica gel and other substances as carriers, and active ingredients containing active metal salts such as tungsten, cobalt, nickel and the like are loaded on the carriers by a certain loading means, and then the catalyst for synthesizing acetonitrile is prepared by extrusion forming, impregnation, calcination, activation and other process methods. However, the catalytic synthesis of acetonitrile by ammoniation of acetic acid with a catalyst has problems of complicated post-treatment, difficult treatment of the deactivated catalyst, and the like. Meanwhile, in the existing method for catalyzing by filling a catalyst in a fixed bed tubular reactor, a side reaction is accompanied in the reaction process, so that the prepared acetonitrile synthetic liquid has high impurity content, low acetonitrile yield, poor stability of a production system and low production safety.
Chinese patent CN109999903A discloses a catalyst for synthesizing acetonitrile and a preparation method thereof, wherein a titanium silicalite molecular sieve is used as a carrier, and metal nitrates (such as potassium nitrate, magnesium nitrate, zinc nitrate, nickel nitrate, gallium nitrate and the like) are loaded on the titanium silicalite molecular sieve. However, in the application process of the catalyst, the post-treatment is complicated, the deactivated catalyst is difficult to treat, and the occurrence of side reactions cannot be effectively reduced; the prepared acetonitrile synthetic liquid has higher impurity content and lower acetonitrile yield.
Therefore, the method for continuously producing high-purity acetonitrile by the micro-channel can reduce side reaction in the reaction process, reduce the impurity content in the acetonitrile synthetic fluid, improve the yield of acetonitrile, improve the stability of a production system and improve the production safety; the method solves the problems of complex post-treatment and difficult treatment of the inactivated catalyst caused by the existing method adopting the catalyst for catalysis, and has important significance for the industrial production of acetonitrile.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention provides a method for continuously producing high-purity acetonitrile by using a micro-channel, which can reduce side reactions in the reaction process, reduce the impurity content in the acetonitrile synthetic solution, improve the acetonitrile yield, improve the stability of a production system and improve the production safety; the method solves the problems of complex post-treatment and difficult treatment of deactivated catalyst caused by the existing method adopting catalyst catalysis.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for continuously producing high-purity acetonitrile by a micro-channel comprises the following steps: preheating, reacting, cooling and rectifying.
Preheating, leading-in respectively acetic acid and liquid ammonia to head tank A, head tank B in, head tank A bottom drain hole and microchannel reaction device's feed inlet pipe connection, head tank B bottom drain hole is through vaporizer and microchannel reaction device's feed inlet pipe connection.
Opening discharge valves at the bottoms of the raw material tank A and the raw material tank B, and metering and conveying the liquid in the raw material tank A into a first microreactor of the microchannel reaction device by a metering pump; after the liquid in the raw material tank B is gasified by a vaporizer, the gas is metered by a metering pump and conveyed into a first microreactor of the microchannel reaction device; controlling the temperature of the first micro reactor to be 125-190 ℃, and the mixing preheating time of the materials in the first micro reactor to be 60-120s, and then entering the second micro reactor.
In the feeding process, the ratio of the acetic acid to the ammonia gas introduced into the first microreactor in unit time is 8.
In the preheating, the total molar ratio of ammonia gas and acetic acid introduced into the first microreactor is 1.03-1.45.
The first micro-reactor is heated by heat conducting oil.
And in the reaction, the temperature of the second microreactor is controlled to be 300-450 ℃, the mixed material preheated by the first microreactor enters the second microreactor to react for 120-480s, the discharge rate of the second microreactor is controlled to be 0.01-0.018kg/s, and the mixed material is discharged to a third microreactor.
The inner wall of the second micro-reactor is made of acidic alumina, and can effectively catalyze the reaction of the mixed materials.
The second micro-reactor is heated by molten salt.
And (3) cooling, namely feeding the material after the reaction in the second microreactor into a third microreactor, cooling by using circulating water, controlling the temperature in the third microreactor to be 75-100 ℃, and controlling the discharge rate of the third microreactor to be 0.01-0.018kg/s to prepare the acetonitrile synthetic fluid.
In the acetonitrile synthetic solution, the acetonitrile content is 50.4-52.6wt%, the water content is 45.0-46.1wt%, the impurity content is 0.19-0.27wt%, the appearance is clear and transparent, no layering phenomenon exists, and the acetonitrile yield is 85.5-90.1%.
And (3) rectifying, namely collecting the cooled acetonitrile synthetic solution, and then rectifying by adopting a continuous rectifying device to prepare the high-purity acetonitrile with the purity of over 99.9 percent.
Wherein the rectification temperature is 80-100 ℃, and the rectification pressure is 0.2-0.5MPa.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the method for continuously producing the high-purity acetonitrile by the microchannel, the microchannel reaction device is adopted, the inner wall made of a specific acidic alumina material is arranged in the second microreactor, the preheating step with specific preset temperature and time is arranged in the first microreactor, and the specific cooling step is arranged in the third microreactor; meanwhile, the occurrence of side reactions in the acetonitrile synthesis process is effectively reduced, and the prepared acetonitrile synthesis solution has the advantages of high acetonitrile content, low impurity content, high acetonitrile yield, good production system stability, high production safety and high environmental friendliness.
(2) The method for continuously producing the high-purity acetonitrile by the micro-channel effectively reduces the occurrence of side reactions in the acetonitrile synthesis process, the prepared acetonitrile synthetic liquid has the acetonitrile content of 50.4-52.6wt%, the water content of 45.0-46.1wt%, the impurity content of 0.19-0.27wt%, the appearance of the acetonitrile synthetic liquid is clear and transparent, the layering phenomenon is avoided, the subsequent refining process of the acetonitrile synthetic liquid is effectively simplified, the refining equipment is reduced, and the refining energy consumption is reduced.
(3) The method for continuously producing high-purity acetonitrile by the micro-channel has the advantages that the yield of acetonitrile in the reaction step is 85.5-90.1%, the stability of a production system is good, the production safety is high, and the micro-channel industrial production of the acetonitrile is realized.
(4) According to the method for continuously producing high-purity acetonitrile by the micro-channel, the prepared acetonitrile synthetic solution is rectified to obtain the high-purity acetonitrile with the purity of over 99.9%, compared with a tubular fixed bed reactor adopting a traditional catalyst, the production energy consumption is reduced by over 10%, and the energy-saving and emission-reducing effects are obvious.
Detailed Description
In order to more clearly understand the technical features, objects, and effects of the present invention, specific embodiments of the present invention will now be described.
Example 1
A method for continuously producing high-purity acetonitrile by using a micro-channel specifically comprises the following steps:
1. preheating
Respectively leading acetic acid and liquid ammonia into a raw material tank A and a raw material tank B, wherein a discharge hole at the bottom of the raw material tank A is connected with a feed inlet pipeline of the microchannel reaction device, and a discharge hole at the bottom of the raw material tank B is connected with the feed inlet pipeline of the microchannel reaction device through a vaporizer.
Starting discharge valves at the bottoms of the raw material tank A and the raw material tank B, and metering and conveying the liquid in the raw material tank A into a first microreactor of the microchannel reaction device by a metering pump; after the liquid in the raw material tank B is gasified by a vaporizer, the gas is metered by a metering pump and conveyed into a first microreactor of the microchannel reaction device; controlling the temperature of the first micro-reactor to be 125 ℃, and the mixing preheating time of the materials in the first micro-reactor to be 120s, and then entering the second micro-reactor.
In the feeding process, the feeding rate of acetic acid in the material tank A is controlled to be 0.080kg/s, and the feeding rate of liquid ammonia in the material tank B is controlled to be 0.023kg/s.
In the preheating step, the total molar ratio of ammonia gas to acetic acid introduced into the first microreactor is 1.03.
The first micro reactor is a plate micro reactor and is heated by heat conducting oil.
2. Reaction(s) of
Controlling the temperature of the second microreactor to be 300 ℃, enabling the mixed material preheated by the first microreactor to enter the second microreactor for reaction for 480s, controlling the discharge rate of the second microreactor to be 0.01kg/s, and discharging to a third microreactor.
The second microreactor is a plate-type microreactor, the inner wall of the second microreactor is made of acidic alumina, and the second microreactor can effectively catalyze the reaction of mixed materials.
The second micro-reactor is heated by molten salt.
3. Temperature reduction
And (3) feeding the material after the reaction in the second microreactor into a third microreactor, controlling the temperature in the third microreactor to be 75 ℃, cooling, and controlling the discharge rate of the third microreactor to be 0.01kg/s to prepare the acetonitrile synthetic fluid.
The third micro-reactor is a plate micro-reactor and adopts circulating water for cooling.
In the acetonitrile synthetic solution, the acetonitrile content is 50.4%, the water content is 46.1%, the impurity content is 0.27%, the appearance is clear and transparent, the layering phenomenon is avoided, and the acetonitrile yield is 85.5%.
4. Rectification
And collecting the cooled acetonitrile synthetic solution, and then rectifying by adopting a continuous rectifying device to obtain the high-purity acetonitrile with the purity of over 99.9 percent.
Wherein the rectification temperature is 80 ℃, and the rectification pressure is 0.5MPa.
Example 2
A method for continuously producing high-purity acetonitrile by a micro-channel specifically comprises the following steps:
1. preheating
Leading-in respectively acetic acid and liquid ammonia to head tank A, head tank B in, head tank A bottom drain hole and microchannel reaction device's feed inlet pipe connection, head tank B bottom drain hole is through vaporizer and microchannel reaction device's feed inlet pipe connection.
Starting discharge valves at the bottoms of the raw material tank A and the raw material tank B, and metering and conveying the liquid in the raw material tank A into a first microreactor of the microchannel reaction device by a metering pump; after the liquid in the raw material tank B is gasified by a vaporizer, the gas is metered by a metering pump and conveyed into a first microreactor of the microchannel reaction device; controlling the temperature of the first microreactor to 145 ℃, and the mixing preheating time of the materials in the first microreactor to 80s, and then feeding the materials into the second microreactor.
In the feeding process, the feeding rate of acetic acid in the stock tank A is controlled to be 0.080kg/s, and the feeding rate of liquid ammonia in the stock tank B is controlled to be 0.023kg/s.
In the preheating step, the total molar ratio of ammonia gas to acetic acid introduced into the first microreactor is 1.25.
The first micro reactor is a plate micro reactor and is heated by heat conducting oil.
2. Reaction of
Controlling the temperature of the second microreactor to be 400 ℃, enabling the mixed material preheated by the first microreactor to enter the second microreactor for reaction for 260s, controlling the discharge rate of the second microreactor to be 0.012kg/s, and discharging to a third microreactor.
The second microreactor is a plate-type microreactor, the inner wall of the second microreactor is made of acidic alumina, and the second microreactor can effectively catalyze the reaction of mixed materials.
The second micro-reactor is heated by molten salt.
3. Temperature reduction
And (3) feeding the material after the reaction in the second microreactor into a third microreactor, controlling the temperature in the third microreactor to be 80 ℃, cooling, and controlling the discharge rate of the third microreactor to be 0.012kg/s to prepare the acetonitrile synthetic fluid.
The third micro-reactor is a plate micro-reactor and adopts circulating water for cooling.
In the acetonitrile synthetic solution, the acetonitrile content is 52.6%, the water content is 45.0%, the impurity content is 0.19%, the appearance is clear and transparent, the layering phenomenon is avoided, and the acetonitrile yield is 90.1%.
4. Rectification
And collecting the cooled acetonitrile synthetic solution, and then rectifying by adopting a continuous rectifying device to obtain the high-purity acetonitrile with the purity of over 99.9 percent.
Wherein the rectification temperature is 85 ℃, and the rectification pressure is 0.42MPa.
Example 3
A method for continuously producing high-purity acetonitrile by using a micro-channel specifically comprises the following steps:
1. preheating
Respectively leading acetic acid and liquid ammonia into a raw material tank A and a raw material tank B, wherein a discharge hole at the bottom of the raw material tank A is connected with a feed inlet pipeline of the microchannel reaction device, and a discharge hole at the bottom of the raw material tank B is connected with the feed inlet pipeline of the microchannel reaction device through a vaporizer.
Starting discharge valves at the bottoms of the raw material tank A and the raw material tank B, and metering and conveying the liquid in the raw material tank A into a first microreactor of the microchannel reaction device by a metering pump; after the liquid in the raw material tank B is gasified by the vaporizer, the gas is metered by the metering pump and conveyed into the first microreactor of the microchannel reaction device; controlling the temperature of the first microreactor to be 160 ℃, and the mixing preheating time of the materials in the first microreactor to be 70s, and then entering the second microreactor.
In the feeding process, the feeding rate of acetic acid in the raw material tank A is controlled to be 0.080kg/s, and the feeding rate of liquid ammonia in the raw material tank B is controlled to be 0.029kg/s.
In the preheating step, the total molar ratio of ammonia to acetic acid introduced into the first microreactor is 1.25.
The first micro reactor is a plate micro reactor and is heated by heat conducting oil.
2. Reaction(s) of
Controlling the temperature of the second microreactor to be 350 ℃, enabling the mixed material preheated by the first microreactor to enter the second microreactor for reaction for 300s, controlling the discharge rate of the second microreactor to be 0.018kg/s, and discharging to a third microreactor.
The second microreactor is a plate-type microreactor, the inner wall of the second microreactor is made of acidic alumina, and the second microreactor can effectively catalyze the reaction of mixed materials.
The second micro-reactor is heated by molten salt.
3. Temperature reduction
And (3) feeding the material after the reaction in the second microreactor into a third microreactor, controlling the temperature in the third microreactor to be 90 ℃, cooling, and controlling the discharge rate of the third microreactor to be 0.018kg/s to prepare the acetonitrile synthetic fluid.
The third micro-reactor is a plate micro-reactor and adopts circulating water for cooling.
In the acetonitrile synthetic solution, the acetonitrile content is 51.7%, the water content is 45.4%, the impurity content is 0.24%, the appearance is clear and transparent, the layering phenomenon is avoided, and the acetonitrile yield is 88.6%.
4. Rectification
And collecting the cooled acetonitrile synthetic solution, and then rectifying by adopting a continuous rectifying device to obtain the high-purity acetonitrile with the purity of over 99.9 percent.
Wherein the rectification temperature is 90 ℃, and the rectification pressure is 0.3MPa.
Example 4
A method for continuously producing high-purity acetonitrile by a micro-channel specifically comprises the following steps:
1. preheating
Respectively leading acetic acid and liquid ammonia into a raw material tank A and a raw material tank B, wherein a discharge hole at the bottom of the raw material tank A is connected with a feed inlet pipeline of the microchannel reaction device, and a discharge hole at the bottom of the raw material tank B is connected with the feed inlet pipeline of the microchannel reaction device through a vaporizer.
Opening discharge valves at the bottoms of the raw material tank A and the raw material tank B, and metering and conveying the liquid in the raw material tank A into a first microreactor of the microchannel reaction device by a metering pump; after the liquid in the raw material tank B is gasified by the vaporizer, the gas is metered by the metering pump and conveyed into the first microreactor of the microchannel reaction device; controlling the temperature of the first microreactor to be 190 ℃, and then enabling the materials to enter a second microreactor after the materials are mixed and preheated in the first microreactor for 60 s.
In the feeding process, the feeding rate of acetic acid in the raw material tank A is controlled to be 0.080kg/s, and the feeding rate of liquid ammonia in the raw material tank B is controlled to be 0.033kg/s.
In the preheating step, the total molar ratio of ammonia gas to acetic acid introduced into the first microreactor is 1.45.
The first micro reactor is a plate micro reactor and is heated by heat conducting oil.
2. Reaction of
Controlling the temperature of the second microreactor to be 450 ℃, enabling the mixed material preheated by the first microreactor to enter the second microreactor for reaction for 120s, controlling the discharge rate of the second microreactor to be 0.017kg/s, and discharging to a third microreactor.
Wherein, the second micro reactor is a plate micro reactor, the inner wall is made of acidic alumina material, and the reaction of the mixed material can be effectively catalyzed.
The second micro-reactor is heated by molten salt.
3. Temperature reduction
And (3) feeding the material after the reaction in the second microreactor into a third microreactor, controlling the temperature in the third microreactor to be 100 ℃, cooling, and controlling the discharge rate of the third microreactor to be 0.017kg/s to prepare the acetonitrile synthetic fluid.
The third micro-reactor is a plate micro-reactor and adopts circulating water for cooling.
In the acetonitrile synthetic solution, the acetonitrile content is 51.2%, the water content is 45.9%, the impurity content is 0.23%, the appearance is clear and transparent, the layering phenomenon is avoided, and the acetonitrile yield is 87.0%.
4. Rectification
And collecting the cooled acetonitrile synthetic solution, and then rectifying by adopting a continuous rectifying device to obtain the high-purity acetonitrile with the purity of over 99.9 percent.
Wherein the rectification temperature is 100 ℃, and the rectification pressure is 0.2MPa.
Comparative example 1
The technical scheme of the embodiment 2 is adopted, and the difference is that in the second step of reaction, a microreactor with an inner wall made of stainless steel is adopted to replace a second microreactor with an inner wall made of acidic alumina; meanwhile, in the first preheating step, acidic alumina microspheres and acetic acid are mixed by a mixer, fed into a first microreactor, preheated for 80 seconds at 80 ℃ by the first microreactor, and fed into a second microreactor for reaction.
The acetonitrile synthetic fluid prepared in the comparative example 1 has the acetonitrile content of 46.5 percent, the water content of 49.8 percent and the impurity content of 0.36 percent, has clear and transparent appearance, does not have the layering phenomenon, and has the acetonitrile yield of 81.1 percent.
All percentages used in the present invention are mass percentages unless otherwise indicated.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. A method for continuously producing high-purity acetonitrile by using a micro-channel is characterized by comprising the following steps: preheating, reacting, cooling and rectifying;
the method comprises the following steps of preheating, namely respectively introducing acetic acid and ammonia gas into a first microreactor of a microchannel reaction device, controlling the temperature of the first microreactor to be 125-190 ℃, mixing and preheating the acetic acid and the ammonia gas in the first microreactor for 60-120s, and then feeding the acetic acid and the ammonia gas into a second microreactor;
in the preheating, the total molar ratio of ammonia gas and acetic acid introduced into the first microreactor is 1.03-1.45;
in the reaction, the temperature of the second microreactor is controlled to be 300-450 ℃, the mixed material preheated by the first microreactor enters the second microreactor to react for 120-480s, the discharge rate of the second microreactor is controlled to be 0.01-0.018kg/s, and the mixed material is discharged to a third microreactor;
in the reaction, the inner wall of the second micro-reactor is made of acidic alumina;
cooling, namely allowing the material reacted in the second microreactor to enter a third microreactor, controlling the temperature in the third microreactor to be 75-100 ℃, and controlling the discharge rate of the third microreactor to be 0.01-0.018kg/s to prepare acetonitrile synthetic fluid;
and the rectification is to rectify the acetonitrile synthetic solution to prepare the high-purity acetonitrile.
2. The method for continuously producing high-purity acetonitrile by the micro-channel according to claim 1, wherein in the preheating, the ratio of the weight parts of acetic acid to the weight parts of ammonia gas introduced into the first micro-reactor per unit time is 8.
3. The method for continuously producing high-purity acetonitrile by the micro-channel according to claim 1, wherein the acetonitrile synthetic solution contains 50.4-52.6wt% of acetonitrile, 45.0-46.1wt% of water and 0.19-0.27wt% of impurities.
4. The method for continuously producing the high-purity acetonitrile by the micro-channel according to claim 1, wherein the first micro-reactor is heated by heat conducting oil; the second micro-reactor is heated by molten salt; and the third microreactor adopts circulating water for temperature control.
5. The method for continuously producing the high-purity acetonitrile by the micro-channel according to claim 1, wherein the rectification is carried out at the temperature of 80-100 ℃ and the rectification pressure of 0.2-0.5MPa.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117417269A (en) * | 2023-12-19 | 2024-01-19 | 潍坊中汇化工有限公司 | Preparation method of anhydrous acetonitrile |
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