CN115010668A - Preparation method of 1-ethyl-3-methylimidazole chloride salt - Google Patents
Preparation method of 1-ethyl-3-methylimidazole chloride salt Download PDFInfo
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- CN115010668A CN115010668A CN202210635411.2A CN202210635411A CN115010668A CN 115010668 A CN115010668 A CN 115010668A CN 202210635411 A CN202210635411 A CN 202210635411A CN 115010668 A CN115010668 A CN 115010668A
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- FQERWQCDIIMLHB-UHFFFAOYSA-N 1-ethyl-3-methyl-1,2-dihydroimidazol-1-ium;chloride Chemical compound [Cl-].CC[NH+]1CN(C)C=C1 FQERWQCDIIMLHB-UHFFFAOYSA-N 0.000 title claims abstract description 17
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims abstract description 258
- 238000006243 chemical reaction Methods 0.000 claims abstract description 138
- MCTWTZJPVLRJOU-UHFFFAOYSA-N 1-methyl-1H-imidazole Chemical compound CN1C=CN=C1 MCTWTZJPVLRJOU-UHFFFAOYSA-N 0.000 claims abstract description 65
- HRYZWHHZPQKTII-UHFFFAOYSA-N chloroethane Chemical compound CCCl HRYZWHHZPQKTII-UHFFFAOYSA-N 0.000 claims abstract description 44
- 229960003750 ethyl chloride Drugs 0.000 claims abstract description 44
- 238000000034 method Methods 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 57
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 50
- 229910052757 nitrogen Inorganic materials 0.000 claims description 25
- 238000010438 heat treatment Methods 0.000 claims description 21
- 238000001816 cooling Methods 0.000 claims description 20
- 239000002608 ionic liquid Substances 0.000 claims description 14
- 238000005119 centrifugation Methods 0.000 claims description 12
- 238000002425 crystallisation Methods 0.000 claims description 12
- 230000008025 crystallization Effects 0.000 claims description 12
- 239000002994 raw material Substances 0.000 claims description 12
- BMQZYMYBQZGEEY-UHFFFAOYSA-M 1-ethyl-3-methylimidazolium chloride Chemical compound [Cl-].CCN1C=C[N+](C)=C1 BMQZYMYBQZGEEY-UHFFFAOYSA-M 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 10
- 238000005086 pumping Methods 0.000 claims description 9
- 239000000498 cooling water Substances 0.000 claims description 8
- 238000000926 separation method Methods 0.000 claims description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 238000011049 filling Methods 0.000 claims description 4
- 239000011888 foil Substances 0.000 claims description 4
- 238000002386 leaching Methods 0.000 claims description 4
- 239000001301 oxygen Substances 0.000 claims description 4
- 229910052760 oxygen Inorganic materials 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims description 4
- WFYJISLZGVEJAE-UHFFFAOYSA-N [Cl].C(C)N1CN(C=C1)C Chemical compound [Cl].C(C)N1CN(C=C1)C WFYJISLZGVEJAE-UHFFFAOYSA-N 0.000 claims description 2
- 230000003647 oxidation Effects 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 claims 1
- 238000004383 yellowing Methods 0.000 claims 1
- 239000000463 material Substances 0.000 description 7
- 239000010963 304 stainless steel Substances 0.000 description 4
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- 238000010907 mechanical stirring Methods 0.000 description 4
- 238000011946 reduction process Methods 0.000 description 4
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 239000000376 reactant Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229920000875 Dissolving pulp Polymers 0.000 description 1
- 239000002000 Electrolyte additive Substances 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 150000005826 halohydrocarbons Chemical class 0.000 description 1
- 150000002460 imidazoles Chemical class 0.000 description 1
- 150000004693 imidazolium salts Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000002892 organic cations Chemical class 0.000 description 1
- 150000004714 phosphonium salts Chemical group 0.000 description 1
- 150000003222 pyridines Chemical class 0.000 description 1
- 150000003242 quaternary ammonium salts Chemical class 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 239000011829 room temperature ionic liquid solvent Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
- C07D233/54—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members
- C07D233/56—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms
- C07D233/58—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having two double bonds between ring members or between ring members and non-ring members with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring carbon atoms with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, attached to ring nitrogen atoms
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A preparation method of 1-ethyl-3-methylimidazole chloride salt comprises the following steps: step 1: replacement; step 2, feeding reaction: adding ethyl acetate into a sealed reaction kettle; adding N-methylimidazole into the sealed kettle; thirdly, adding chloroethane into the sealed reaction kettle; and step 3: crystallizing; and 4, step 4: separating; and 5: and (5) storing. Compared with the prior art, the method can control the reaction temperature within the range of 70-77 ℃, control the reaction temperature and pressure below 0.20 MPa, improve the yield to over 90.4 percent, stabilize the product purity to over 99 percent and obviously improve the product chromaticity.
Description
Technical Field
The invention belongs to the field of chemical industry, and particularly relates to a preparation method of 1-ethyl-3-methylimidazole chloride salt.
Background
A substance composed of ions which is liquid at or near room temperature is called a room-temperature ionic liquid, which is simply referred to as an ionic liquid. Ionic liquids can be classified into four major classes, namely, imidazole salts, pyridine salts, quaternary ammonium salts and quaternary phosphonium salts, according to the difference of organic cations.
The 1-ethyl-3-methylimidazolium chloride is an imidazolium salt, is a white or light yellow crystalline solid in appearance, is easily soluble in water, dichloromethane, ethanol, acetonitrile and the like, is insoluble in ethyl acetate, diethyl ether, alkane and the like, and is mainly applied to dissolving cellulose, electrolyte additives and the like.
The conventional preparation process of 1-ethyl-3-methylimidazole chloride salt mainly comprises the steps of directly adding materials, heating and pressurizing to react, namely, N-methylimidazole and alkyl salt or halohydrocarbon directly react in a proper solvent in one step to synthesize the product. The reaction is carried out in a reaction kettle, the reaction needs heating, the reaction kettle is generally heated in a water bath jacket mode, when the water temperature of a jacket reaches a certain temperature value, the materials in the kettle are induced to carry out extremely unstable exothermic reaction, the temperature in the kettle rises to over 90 ℃, but the product yield is reduced and the product color is yellowed when the material temperature exceeds 80 ℃, the product quality is finally influenced, the defective rate is greatly increased, and the raw materials can not fully react when the temperature is lower than 70 ℃, so the temperature of the reaction kettle needs to be controlled to be near 75 ℃ in the reaction process. In order to control the temperature of the reaction kettle to be about 75 ℃, the temperature needs to be raised or lowered continuously in the whole reaction process, which brings great difficulty to production operators. In addition, the reaction temperature rises sharply, the pressure in the kettle is increased, the pressure can reach 0.68 MPa, and the potential safety hazard is increased. In addition, the yield of the product produced by the process method is about 85 percent, the chroma of the product is 15, and the purity stability of the product is poor.
Disclosure of Invention
The invention aims to solve the technical problems that in the preparation process of 1-ethyl-3-methylimidazole chloride salt, the phenomena of low product yield, poor quality stability and potential safety hazard caused by the phenomena of high reaction temperature and high pressure in a kettle are not easy to control, and provides a novel preparation method of 1-ethyl-3-methylimidazole chloride salt for solving the problems.
The object of the invention is achieved in the following way:
a preparation method of 1-ethyl-3-methylimidazole chloride salt comprises the following steps:
step 1: replacement of
Replacing the sealed reaction kettle with nitrogen for 2-3 times, and keeping the pressure in the kettle at micro-positive pressure of 0.06-0.08 MPa after replacement;
step 2: reaction of addition
Adding ethyl acetate into a sealed reaction kettle;
adding N-methylimidazole into the sealed kettle, wherein the molar ratio of the N-methylimidazole to the ethyl acetate is 1: 0.16-1: 0.27;
after the two raw materials are completely added, performing primary replacement by using nitrogen; after the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.03 to-0.02 MPa;
thirdly, adding ethyl chloride into the sealed reaction kettle, wherein the molar ratio of the N-methylimidazole to the ethyl chloride is 1: 1.07-1: 1.18, and starting stirring; opening a hot water valve of a jacket of the reaction kettle, introducing hot water at the temperature of 40-60 ℃, heating the water bath temperature to 75 ℃ after 3 hours, reacting for 20-28 hours at the temperature, and controlling the pressure in the kettle to be 0.16-0.18 Mpa;
and step 3: crystallization of
After the reaction of the raw materials is finished, closing a hot water valve, opening a jacket of a reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, wherein the molar ratio of the N-methylimidazole to the added ethyl acetate is 1: 0.64-1: 0.88, and continuously cooling after the ethyl acetate is added, so that the product is slowly crystallized in the cooling process; when the temperature in the kettle is reduced to 10-20 ℃, stopping reducing the temperature and keeping the temperature for 2 hours, so that the product is fully crystallized in the kettle;
and 4, step 4: separation of
After the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 5-10 min (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine in the product centrifugation process, replacing air, preventing 1-ethyl-3-methylimidazole chloride from absorbing moisture and oxygen in the air in the centrifugation process to increase the water content of the product and oxidize and turn yellow the product, and meanwhile, centrifugally leaching the crystallized product by using ethyl acetate;
and 5: storing
Quickly filling the centrifuged product 1-ethyl-3-methylimidazolium chloride into an aluminum foil bag, vacuumizing, sealing and storing.
And the third step of the step 2 is as follows: adding ethyl chloride into a sealed reaction kettle, wherein the molar ratio of the N-methylimidazole to the ethyl chloride is 1: 1.07-1: 1.18, and starting stirring; opening a hot water valve of a jacket of the reaction kettle, introducing hot water at the temperature of 40-60 ℃, heating the water bath to 75 ℃ after 3 h, reacting for 10-14 h at the temperature, heating the water bath to 77.1-77.5 ℃, reacting for 8-12 h at the temperature, and controlling the pressure in the kettle to be 0.16-0.18 Mpa.
The preparation method of the 1-ethyl-3-methylimidazole chloride ionic liquid comprises the following steps:
step 1: replacement of
Firstly, replacing the sealed reaction kettle with nitrogen for 2-3 times, and keeping the pressure in the kettle at the micro-positive pressure of 0.07 MPa after the replacement is finished;
step 2: reaction of addition
Firstly, adding ethyl acetate into a sealed reaction kettle;
adding N-methylimidazole into the sealed kettle, wherein the molar ratio of the N-methylimidazole to the ethyl acetate is 1: 0.21;
after the two raw materials are completely added, performing primary replacement by using nitrogen; after the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.025 MPa;
thirdly, adding chloroethane into the sealed reaction kettle, wherein the molar ratio of the N-methylimidazole to the chloroethane is 1:1.12, and starting stirring; opening a hot water valve of a jacket of the reaction kettle, introducing hot water at 50 ℃, heating the water bath temperature to 75 ℃ after 3 hours, reacting for 12 hours at the temperature, heating the water bath temperature to 77.3 ℃, reacting for 10 hours at the temperature, and controlling the pressure in the kettle to be 0.17 Mpa;
and step 3: crystallization of
After the reaction of the raw materials is finished, closing a hot water valve, opening a jacket of the reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, wherein the molar ratio of the N-methylimidazole to the added ethyl acetate is 1:0.76, and continuously cooling after the addition of the ethyl acetate is finished to slowly crystallize a product in the cooling process; when the temperature in the kettle is reduced to 15 ℃, stopping reducing the temperature and keeping the temperature for 2 hours, so that the product is fully crystallized in the kettle;
and 4, step 4: separation of
After the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 8 min (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine in the product centrifugation process, replacing air, preventing 1-ethyl-3-methylimidazole chlorine salt from absorbing moisture and oxygen in the air in the centrifugation process to increase the water content of the product and oxidize and turn yellow the product, and meanwhile, centrifugally leaching the crystallized product by using ethyl acetate;
and 5: storing
Quickly filling the centrifuged product 1-ethyl-3-methylimidazolium chloride into an aluminum foil bag, vacuumizing, sealing and storing.
Compared with the prior art, the method can control the reaction temperature within the range of 70-77 ℃, control the reaction temperature pressure below 0.20 MPa, improve the yield to over 90.4 percent, stabilize the product purity to over 99 percent and obviously improve the product chromaticity.
The principle of the invention for achieving the effect is as follows:
1. ethyl acetate is added before the N-methylimidazole and the chloroethane are added into the reaction kettle, because the ethyl acetate does not participate in the reaction, but can dilute the concentration of the raw materials, increase the reaction space of the raw materials and reduce the exothermic effect of the raw materials during the reaction;
2. the reaction pressure is between 0.16 and 0.18 Mpa, the boiling point of the ethyl acetate under the pressure is about 77 ℃, and the reaction temperature is close to 75 ℃. When the reaction temperature reaches 77 ℃, ethyl acetate boils, a large amount of heat is absorbed by evaporation, the ethyl acetate is changed into a gaseous state and moves to the top of the reaction kettle, the temperature at the top of the reaction kettle is lower than 77 ℃, the gaseous ethyl acetate is liquefied and flows down along the side wall of the reaction kettle, and the heat is released.
In view of the above two methods, the reaction temperature is controlled to be in the range of 70-77 ℃ and the pressure is controlled to be below 0.2 MPa.
Detailed Description
Example 1
A preparation method of 1-ethyl-3-methylimidazole chloride ionic liquid comprises the following steps:
step 1, replacement: the material of the reaction kettle is 304 stainless steel, the capacity is 300L, and the reaction kettle is provided with a jacket for heating (cooling). Replacing air in the reaction kettle with nitrogen for 2 times or 3 times, wherein after replacement is finished, the pressure in the reaction kettle keeps micro-positive pressure of 0.06 MPa, or 0.08 MPa, or 0.07 MPa, and any value between 0.06 MPa and 0.08 MPa is carried out in the implementation process; the addition was started.
Step 2, charging: sequentially adding ethyl acetate and N-methylimidazole into a sealed reaction kettle, and adding 15 kg of ethyl acetate and 85 kg of N-methylimidazole into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.16; or adding 25 kg of ethyl acetate and 85 kg of N-methylimidazole into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.27; 19 kg of ethyl acetate and 85 kg of N-methylimidazole can be added into the sealed reaction kettle according to the molar ratio of 1:0.21 of the N-methylimidazole to the ethyl acetate; in the implementation process, the proportion is converted into the mass of the added ethyl acetate according to any numerical value of the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.16-1: 0.27, and then the ethyl acetate is added; then the air in the reaction kettle is replaced by nitrogen. After the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.03 MPa, or-0.02 MPa, or-0.025 MPa, wherein any value between-0.03 MPa and-0.02 MPa is realized in the implementation process; then adding ethyl chloride into the sealed reaction kettle according to the proportion that the molar ratio of the N-methylimidazole to the ethyl chloride is 1:1.07, and adding 71.5 kg of ethyl chloride into the sealed reaction kettle; 78.81kg of chloroethane can be added into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the chloroethane of 1: 1.18; 74.82 kg of chloroethane can be added into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the chloroethane of 1: 1.12; in the implementation process, according to any numerical value of the molar ratio of the N-methylimidazole to the chloroethane of 1: 1.07-1: 1.18, the weight of the chloroethane is converted, and then the chloroethane is added; stirring, opening a hot water valve of a jacket of the reaction kettle, introducing 40 ℃ hot water, wherein the temperature of the hot water can be 60 ℃, or 50 ℃, any value between 40 ℃ and 60 ℃ is realized in the implementation process, heating the water bath to 75 ℃ after 3 h, reacting for 20 h, or 28 h, or 24 h, any value between 20 h and 28 h is realized in the implementation process, the pressure in the kettle is controlled to be 0.16 MPa, or 0.18 MPa, or 0.17 MPa, or any value between 0.16 MPa and 0.18 MPa in the implementation process.
Step 3, crystallization: and after the reaction is finished, closing the hot water valve. Opening a jacket of the reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, and adding 58 kg of ethyl acetate into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.64; or adding 80 kg of ethyl acetate into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.88; 69 kg of ethyl acetate can be added into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.76; in the implementation process, the proportion is converted into the mass of the added ethyl acetate according to any numerical value of the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.64-1: 0.88, and then the ethyl acetate is added; the product starts to crystallize when the temperature drops below 45 ℃; then, the temperature is continuously and slowly reduced to be below 20 ℃, so that the product is slowly crystallized in the temperature reduction process, and the temperature is kept for 2 hours, so that the product is fully crystallized. Because the product in the kettle is easy to be instantaneously crystallized due to the too fast temperature reduction, and mechanical accidents are caused by the dead mechanical stirring, the temperature can not be reduced too fast in the crystallization process.
And 4, separation: after the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 5 min, or 10 min, or 8 min, wherein any value between 5 min and 10 min is carried out (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine for protection in the product centrifugation process, and simultaneously cleaning the crystallized product by using 25 kg of ethyl acetate; finally, the ionic liquid 1-ethyl-3-methylimidazole chloride salt can be obtained.
Selecting the minimum value, the maximum value and the intermediate value of all process parameters to obtain the conditions of the quality, the yield and the chromaticity of the 1-ethyl-3-methylimidazolium chloride ionic liquid:
1. a preparation method of 1-ethyl-3-methylimidazole chloride ionic liquid comprises the following steps:
step 1, replacement:
the material of the reaction kettle is 304 stainless steel, the capacity is 300L, and the reaction kettle is provided with a jacket for heating (cooling). Replacing air in the reaction kettle with nitrogen for 2 times, and keeping the pressure in the kettle at the micro-positive pressure of 0.06 MPa after the replacement is finished; the addition was started.
Step 2, feeding:
sequentially adding ethyl acetate and N-methylimidazole into a sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1:0.16, adding 15 kg of ethyl acetate and 85 kg of N-methylimidazole into the sealed reaction kettle, and replacing air in the reaction kettle with nitrogen; after the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.02 MPa; then adding chloroethane into the sealed reaction kettle, and adding 71.5 kg of chloroethane into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the chloroethane of 1: 1.07; stirring, opening a hot water valve of a jacket of the reaction kettle, introducing hot water of 40 ℃, heating in a water bath to 75 ℃ after 3 hours, reacting for 20 hours at the temperature, and naturally increasing the pressure in the kettle to 0.16 MPa.
Step 3, crystallization:
and after the reaction is finished, closing the hot water valve. Opening a jacket of the reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, and adding 58 kg of ethyl acetate into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.64; the product starts to crystallize when the temperature drops below 45 ℃; then, the temperature is continuously and slowly reduced to be below 20 ℃, so that the product is slowly crystallized in the temperature reduction process, and the temperature is kept for 2 hours, so that the product is fully crystallized. Because the product in the kettle is easy to be instantaneously crystallized due to the too fast temperature reduction, and mechanical accidents are caused by the dead mechanical stirring, the temperature can not be reduced too fast in the crystallization process.
And 4, separation:
after the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 5 min (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine for protection in the product centrifugation process, and simultaneously cleaning the crystallized product by using 25 kg of ethyl acetate;
the yield of the obtained 1-ethyl-3-methylimidazolium chloride ionic liquid is 145.92 kg, the yield is 91.3%, the yield is improved by 6%, the purity is 99.23%, the product chromaticity is 5, the previous chromaticity is 15, and the product chromaticity is obviously improved.
2. A preparation method of 1-ethyl-3-methylimidazole chloride ionic liquid comprises the following steps:
step 1, replacement:
the material of the reaction kettle is 304 stainless steel, the capacity is 300L, and the reaction kettle is provided with a jacket for heating (cooling). Replacing air in the reaction kettle with nitrogen for 3 times, and keeping the pressure in the kettle at the micro-positive pressure of 0.08 MPa after the replacement is finished; the addition was started.
Step 2, feeding:
sequentially adding ethyl acetate and N-methylimidazole into a sealed reaction kettle, and adding 25 kg of ethyl acetate and 85 kg of N-methylimidazole into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.27; then the air in the reaction kettle is replaced by nitrogen. After the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.02 MPa. And then adding ethyl chloride into the sealed reaction kettle, adding 78.81kg of ethyl chloride into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl chloride of 1:1.18, starting stirring, opening a hot water valve of a jacket of the reaction kettle, introducing 60 ℃ hot water, heating the water bath to 75 ℃ after 3 hours, reacting for 28 hours at the temperature, and naturally increasing the pressure in the kettle to 0.16 MPa.
Step 3, crystallization:
and after the reaction is finished, closing the hot water valve. Opening a jacket of the reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, and adding 80 kg of ethyl acetate into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.88; the product starts to crystallize when the temperature drops below 45 ℃; then, the temperature is continuously and slowly reduced to be below 20 ℃, so that the product is slowly crystallized in the temperature reduction process, and the temperature is kept for 2 hours, so that the product is fully crystallized. Because the product in the kettle is easy to be instantaneously crystallized due to the too fast temperature reduction, and mechanical accidents are caused by the dead mechanical stirring, the temperature can not be reduced too fast in the crystallization process.
And 4, separation:
after the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 10 min (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine for protection in the product centrifugation process, and simultaneously cleaning the crystallized product by using 25 kg of ethyl acetate;
the yield of the obtained 1-ethyl-3-methylimidazolium chloride ionic liquid is 151.2 kg, the yield is 92.3%, the yield is improved by 5%, the purity is 99.38%, the chroma of the product is less than or equal to 5, the chroma is 15 before, and the chroma of the product is improved very high.
3. A preparation method of 1-ethyl-3-methylimidazole chloride ionic liquid comprises the following steps:
step 1, replacement:
the material of the reaction kettle is 304 stainless steel, the capacity is 300L, and the reaction kettle is provided with a jacket for heating (cooling). Replacing air in the reaction kettle with nitrogen for 3 times, and keeping the pressure in the kettle at the micro-positive pressure of 0.07 Mpa after the replacement is finished; the addition was started.
Step 2, charging:
adding ethyl acetate and N-methylimidazole into a sealed reaction kettle in sequence, adding 19 kg of ethyl acetate and 85 kg of N-methylimidazole into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1:0.21, and replacing air in the reaction kettle with nitrogen. After the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.02 MPa. And then adding ethyl chloride into the sealed reaction kettle, adding 74.82 kg of ethyl chloride into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl chloride of 1:1.12, starting stirring, opening a hot water valve of a jacket of the reaction kettle, introducing 50 ℃ hot water, heating the mixture in a water bath to 75 ℃ after 3 hours, reacting for 24 hours at the temperature, and naturally increasing the pressure in the kettle to 0.16 MPa.
Step 3, crystallization:
and after the reaction is finished, closing the hot water valve. Opening a jacket of the reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, and adding 69 kg of ethyl acetate into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.76; the product starts to crystallize when the temperature drops below 45 ℃; then, the temperature is continuously and slowly reduced to be below 20 ℃, so that the product is slowly crystallized in the temperature reduction process, and the temperature is kept for 2 hours, so that the product is fully crystallized. Because the product in the kettle is easy to be instantaneously crystallized due to the too fast temperature reduction, and mechanical accidents are caused by the dead mechanical stirring, the temperature can not be reduced too fast in the crystallization process.
And 4, separation:
after the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 8 min (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine for protection in the product centrifugation process, and simultaneously cleaning the crystallized product by using 25 kg of ethyl acetate;
the yield of the obtained 1-ethyl-3-methylimidazolium chloride ionic liquid is 142 kg, the yield is 90.8%, the yield is improved by 5%, the purity is 99.30%, the chroma of the product is less than or equal to 5, the previous chroma is 15, and the chroma of the product is obviously improved.
Example 2
The other steps are the same as in example 1 except for step 2.
Step 2, feeding:
sequentially adding ethyl acetate and N-methylimidazole into a sealed reaction kettle, and adding 15 kg of ethyl acetate and 85 kg of N-methylimidazole into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.16; or adding 25 kg of ethyl acetate and 85 kg of N-methylimidazole into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.27; 19 kg of ethyl acetate and 85 kg of N-methylimidazole can be added into the sealed reaction kettle according to the molar ratio of 1:0.21 of the N-methylimidazole to the ethyl acetate; in the implementation process, the proportion is converted into the mass of the added ethyl acetate according to any numerical value of the molar ratio of the N-methylimidazole to the ethyl acetate of 1: 0.16-1: 0.27, and then the ethyl acetate is added; then the air in the reaction kettle is replaced by nitrogen. After the replacement is finished, pumping the mixture into a reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.03 MPa, or-0.02 MPa, or-0.025 MPa, wherein any value between-0.03 and-0.02 MPa is realized in the implementation process; then adding ethyl chloride into the sealed reaction kettle according to the proportion that the molar ratio of the N-methylimidazole to the ethyl chloride is 1:1.07, and adding 71.5 kg of ethyl chloride into the sealed reaction kettle; 78.81kg of chloroethane can be added into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the chloroethane of 1: 1.18; 74.82 kg of chloroethane can be added into the sealed reaction kettle according to the molar ratio of the N-methylimidazole to the chloroethane of 1: 1.12; in the implementation process, according to any numerical value of the molar ratio of the N-methylimidazole to the chloroethane of 1: 1.07-1: 1.18, the weight of the chloroethane is converted, and then the chloroethane is added; stirring, opening a hot water valve of a jacket of a reaction kettle, introducing 40 ℃ hot water, wherein the temperature of the hot water can be 60 ℃, or 50 ℃, any value between 40 ℃ and 60 ℃ is realized in the implementation process, heating the water bath to 75 ℃ after 3 hours, reacting for 10 hours, or 12 hours, or 11 hours, any value between 10 hours and 12 hours in the implementation process, introducing 77.1 ℃ hot water, wherein the temperature of the hot water can be 77.5 ℃, or 77.3 ℃, any value between 77.1 ℃ and 77.5 ℃ in the implementation process, evaporating a large amount of ethyl acetate in the kettle to be gaseous, fully contacting the residual N-methylimidazole with chloroethane, accelerating the reaction rate, reacting for 8 hours, or 12 hours, or reacting for 10 hours, and any value between 8 hours and 12 hours in the implementation process, the pressure in the kettle naturally rises to 0.16 MPa. The invention can control the reaction temperature in the range of 70-75 ℃ in the first stage and 77.0-77.5 ℃ in the second stage, and because most products produced after the reaction in the first stage greatly reduce the concentration of reactants, the phenomenon of rapid temperature rise can not occur, ethyl acetate is evaporated, the concentration of the reactants is relatively increased, and the reaction speed is increased.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the overall concept of the present invention, and these should also be considered as the protection scope of the present invention.
Claims (3)
1. A preparation method of 1-ethyl-3-methylimidazole chloride salt comprises the following steps:
step 1: replacement of
Replacing the sealed reaction kettle with nitrogen for 2-3 times, and keeping the pressure in the kettle at micro-positive pressure of 0.06-0.08 MPa after replacement;
step 2: reaction of addition
Adding ethyl acetate into a sealed reaction kettle;
adding N-methylimidazole into the sealed kettle, wherein the molar ratio of the N-methylimidazole to the ethyl acetate is 1: 0.16-1: 0.27;
after the two raw materials are added, performing primary replacement by using nitrogen; after the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.03 to-0.02 MPa;
thirdly, adding ethyl chloride into the sealed reaction kettle, wherein the molar ratio of the N-methylimidazole to the ethyl chloride is 1: 1.07-1: 1.18, and starting stirring; opening a hot water valve of a jacket of the reaction kettle, introducing hot water at the temperature of 40-60 ℃, heating the water bath temperature to 75 ℃ after 3 hours, reacting for 20-28 hours at the temperature, and controlling the pressure in the kettle to be 0.16-0.18 Mpa;
and 3, step 3: crystallization of
After the reaction of the raw materials is finished, closing a hot water valve, opening a jacket of a reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, wherein the molar ratio of the N-methylimidazole to the added ethyl acetate is 1: 0.64-1: 0.88, and continuously cooling after the ethyl acetate is added, so that the product is slowly crystallized in the cooling process; when the temperature in the kettle is reduced to 10-20 ℃, stopping reducing the temperature and keeping the temperature for 2 hours, so that the product is fully crystallized in the kettle;
and 4, step 4: separation of
After the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 5-10 min (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine in the product centrifugation process, replacing air, preventing 1-ethyl-3-methylimidazole chloride from absorbing moisture and oxygen in the air in the centrifugation process to increase the water content of the product and oxidize and turn yellow the product, and meanwhile, centrifugally leaching the crystallized product by using ethyl acetate;
and 5: storing
Quickly filling the centrifuged product 1-ethyl-3-methylimidazolium chloride into an aluminum foil bag, vacuumizing, sealing and storing.
2. The preparation method of the 1-ethyl-3-methylimidazolium chloride ionic liquid according to patent claim 1, characterized in that the third step in step 2 is: adding ethyl chloride into a sealed reaction kettle, wherein the molar ratio of the N-methylimidazole to the ethyl chloride is 1: 1.07-1: 1.18, and starting stirring; opening a hot water valve of a jacket of the reaction kettle, introducing hot water at the temperature of 40-60 ℃, heating the water bath to 75 ℃ after 3 h, reacting for 10-14 h at the temperature, heating the water bath to 77.1-77.5 ℃, reacting for 8-12 h at the temperature, and controlling the pressure in the kettle to be 0.16-0.18 Mpa.
3. The preparation method of the 1-ethyl-3-methylimidazolium chloride ionic liquid according to patent claim 2, characterized by comprising the following steps:
step 1: replacement of
Firstly, replacing the sealed reaction kettle with nitrogen for 2-3 times, and keeping the pressure in the kettle at the micro-positive pressure of 0.07 MPa after the replacement is finished;
step 2: reaction of addition
Adding ethyl acetate into a sealed reaction kettle;
adding N-methylimidazole into the sealed kettle, wherein the molar ratio of the N-methylimidazole to the ethyl acetate is 1: 0.21;
after the two raw materials are completely added, performing primary replacement by using nitrogen; after the replacement is finished, pumping the mixture into the reaction kettle by using a vacuum pump to keep the micro negative pressure of-0.025 MPa;
thirdly, adding ethyl chloride into the sealed reaction kettle, wherein the molar ratio of the N-methylimidazole to the ethyl chloride is 1:1.12, and starting stirring; opening a hot water valve of a jacket of the reaction kettle, introducing hot water at 50 ℃, heating the water bath temperature to 75 ℃ after 3 hours, reacting for 12 hours at the temperature, heating the water bath temperature to 77.3 ℃, reacting for 10 hours at the temperature, and controlling the pressure in the kettle to be 0.17 Mpa;
and step 3: crystallization of
After the reaction of the raw materials is finished, closing a hot water valve, opening a jacket of a reaction kettle to circulate cooling water, slowly cooling to 55 ℃, adding ethyl acetate, wherein the molar ratio of the N-methylimidazole to the added ethyl acetate is 1:0.76, and continuously cooling after the ethyl acetate is added, so that the product is slowly crystallized in the cooling process; when the temperature in the kettle is reduced to 15 ℃, stopping reducing the temperature and keeping the temperature for 2 hours, so that the product is fully crystallized in the kettle;
and 4, step 4: separation of
After the product is completely crystallized, quickly transferring the product to a centrifugal machine, centrifuging for 8 min (the rotating speed is 500 r/min), continuously introducing nitrogen into the centrifugal machine in the product centrifugation process, replacing air, preventing 1-ethyl-3-methylimidazole chlorine salt from absorbing water and oxygen in the air in the centrifugation process to cause the increase of the water content of the product and the oxidation and yellowing of the product, and meanwhile, centrifugally leaching the crystallized product by using ethyl acetate;
and 5: storing
Quickly filling the centrifuged product 1-ethyl-3-methylimidazolium chloride into an aluminum foil bag, vacuumizing, sealing and storing.
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