CN114349678A - Continuous industrial production method of N-alkyl-nitrophthalimide - Google Patents
Continuous industrial production method of N-alkyl-nitrophthalimide Download PDFInfo
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- CN114349678A CN114349678A CN202111404474.9A CN202111404474A CN114349678A CN 114349678 A CN114349678 A CN 114349678A CN 202111404474 A CN202111404474 A CN 202111404474A CN 114349678 A CN114349678 A CN 114349678A
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- 238000006396 nitration reaction Methods 0.000 claims abstract description 28
- 238000001035 drying Methods 0.000 claims abstract description 24
- 239000002994 raw material Substances 0.000 claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 claims abstract description 19
- 238000007865 diluting Methods 0.000 claims abstract description 9
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- 239000012074 organic phase Substances 0.000 claims description 51
- 238000002425 crystallisation Methods 0.000 claims description 44
- 230000008025 crystallization Effects 0.000 claims description 44
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 35
- 238000002156 mixing Methods 0.000 claims description 34
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- 238000006386 neutralization reaction Methods 0.000 claims description 15
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- 230000014759 maintenance of location Effects 0.000 claims description 10
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- 230000002431 foraging effect Effects 0.000 claims description 9
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- OXMDWHVDKVTUQL-UHFFFAOYSA-N 2-(3-methylbutyl)isoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCC(C)C)C(=O)C2=C1 OXMDWHVDKVTUQL-UHFFFAOYSA-N 0.000 claims description 5
- JZDSOQSUCWVBMV-UHFFFAOYSA-N 2-ethylisoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CC)C(=O)C2=C1 JZDSOQSUCWVBMV-UHFFFAOYSA-N 0.000 claims description 5
- ZXLYYQUMYFHCLQ-UHFFFAOYSA-N 2-methylisoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(C)C(=O)C2=C1 ZXLYYQUMYFHCLQ-UHFFFAOYSA-N 0.000 claims description 5
- 125000000217 alkyl group Chemical group 0.000 claims description 5
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 5
- 239000002904 solvent Substances 0.000 claims description 5
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 claims description 4
- QUSNBJAOOMFDIB-UHFFFAOYSA-N Ethylamine Chemical compound CCN QUSNBJAOOMFDIB-UHFFFAOYSA-N 0.000 claims description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 4
- BAVYZALUXZFZLV-UHFFFAOYSA-N Methylamine Chemical compound NC BAVYZALUXZFZLV-UHFFFAOYSA-N 0.000 claims description 4
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 4
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 4
- WGYKZJWCGVVSQN-UHFFFAOYSA-N propylamine Chemical compound CCCN WGYKZJWCGVVSQN-UHFFFAOYSA-N 0.000 claims description 4
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 claims description 3
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 claims description 3
- 238000013517 stratification Methods 0.000 claims description 3
- DLKDEVCJRCPTLN-UHFFFAOYSA-N 2-butylisoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCCC)C(=O)C2=C1 DLKDEVCJRCPTLN-UHFFFAOYSA-N 0.000 claims description 2
- RLARUBPTQYKZKA-UHFFFAOYSA-N 2-propylisoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCC)C(=O)C2=C1 RLARUBPTQYKZKA-UHFFFAOYSA-N 0.000 claims description 2
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 claims description 2
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims description 2
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 2
- 125000004432 carbon atom Chemical group C* 0.000 claims description 2
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 239000011736 potassium bicarbonate Substances 0.000 claims description 2
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 2
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 2
- 239000012670 alkaline solution Substances 0.000 claims 1
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- JBCHWGTZAAZJKG-UHFFFAOYSA-N 2-methyl-5-nitroisoindole-1,3-dione Chemical compound C1=C([N+]([O-])=O)C=C2C(=O)N(C)C(=O)C2=C1 JBCHWGTZAAZJKG-UHFFFAOYSA-N 0.000 description 3
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- ZFOUJAHAOQQDPB-UHFFFAOYSA-N 4-nitro-2-propan-2-ylisoindole-1,3-dione Chemical compound C1=CC([N+]([O-])=O)=C2C(=O)N(C(C)C)C(=O)C2=C1 ZFOUJAHAOQQDPB-UHFFFAOYSA-N 0.000 description 2
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- OFJQZKXNQMOMHY-UHFFFAOYSA-N 2-ethyl-4-nitroisoindole-1,3-dione Chemical compound C1=CC([N+]([O-])=O)=C2C(=O)N(CC)C(=O)C2=C1 OFJQZKXNQMOMHY-UHFFFAOYSA-N 0.000 description 1
- FWIZOFDVGZCRTB-UHFFFAOYSA-N 2-methyl-4-nitroisoindole-1,3-dione Chemical compound C1=CC([N+]([O-])=O)=C2C(=O)N(C)C(=O)C2=C1 FWIZOFDVGZCRTB-UHFFFAOYSA-N 0.000 description 1
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- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
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- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
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- 125000000959 isobutyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])* 0.000 description 1
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Abstract
The invention discloses a continuous industrial production method of N-alkyl-nitrophthalimide, which comprises the following steps: (1) pretreating raw materials; (2) continuous nitrification; (3) aging; (4) diluting and layering; (5) neutralizing and layering; (6) crystallizing, separating and drying; the whole production operation process is dynamically and continuously carried out to prepare the N-alkyl-nitrophthalimide. The method adopts the microchannel reactor to carry out continuous nitration reaction, does not need to use an organic extractant for extraction in the post-treatment process, is simple to operate, safe and environment-friendly, and has high product yield and high purity (the product purity is more than or equal to 99.5%); the whole production process of the raw material reaction and the post-treatment operation is dynamically and continuously carried out, the production efficiency is high, the labor cost is greatly reduced, the quality of the final product is stable and controllable, and large-scale industrial production can be realized.
Description
Technical Field
The invention relates to the technical field of chemical industry, in particular to a continuous industrial production method of N-alkyl-nitrophthalimide.
Background
N-alkyl-nitrophthalimide is an important chemical intermediate, and has a very important position in the industries of chemical engineering, medical treatment, dye and the like. The structure is shown as formula I:
Wherein, R can be alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, pentyl and the like.
At present, the method for preparing N-alkyl-nitrophthalimide generally takes N-alkyl-phthalimide as a reaction raw material, and the reaction is carried out in the presence of a nitration reagent, a catalyst and a dehydrating agent. Chinese patent application CN104086476A discloses a preparation method of 4-nitro-N-methylphthalimide, firstly cooling fuming nitric acid to 5-10 ℃, then dropwise adding concentrated sulfuric acid with a metering ratio, and preparing mixed acid at 10-15 ℃; stirring and dissolving N-methylphthalimide and concentrated sulfuric acid at 0 ℃, then dropwise adding mixed acid, reacting for 3-4 h, extracting a nitride in the reaction by using an organic extractant, and separating an upper organic phase and a lower sulfuric acid solution after layering; recovering the upper organic phase to obtain 4-nitro-N-methyl phthalimide, centrifuging, filtering and drying to obtain the finished product. The preparation method adopts a mode of dropwise adding the nitrating agent to carry out intermittent reaction, is similar to the traditional kettle-type nitration process, is difficult to carry out uniform mass and heat transfer, is difficult to remove reaction heat in time, is easy to cause temperature runaway of the reaction, thereby causing safety accidents, and is not suitable for industrial production under the chemical industry environment at present.
In recent years, the application of the microchannel reactor in nitration reaction is more and more extensive, and compared with the conventional tank reactor, the microchannel reactor has the advantages of small liquid holdup, safety, quick material heating and heat transfer reaction, uniform material mixing and the like. Chinese patent application CN109305933A discloses a method for preparing N-alkyl-4-nitrophthalimide, which adopts microchannel reactors with different structures to carry out nitration reaction of N-alkylphthalimide, and carries out post-treatment operations such as cooling, water washing, filtering, collecting, drying and the like after the reaction is finished, thereby preparing the N-methyl-4-nitrophthalimide. However, the preparation method realizes continuity only in the nitration reaction process, the subsequent extraction process of the product is still a traditional intermittent post-treatment mode, the finally obtained product has low purity, the purity requirement of the subsequent reaction cannot be met, and the product can be used for the next reaction after further purification; and the subsequent treatment adopts a water washing mode, so that a large amount of acidic waste liquid can be generated, more energy is consumed during recovery, and the production cost is increased; in addition, the quality of the final product is difficult to control stably in the batch production process, which is a problem faced in the traditional industrial production at present.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a continuous industrial production method of N-alkyl-nitrophthalimide, which has the advantages of high reaction yield, high product purity, stable and controllable product quality.
The invention is realized by the following technical scheme:
a continuous industrial production method of N-alkyl-nitrophthalimide comprises the following steps: (1) pretreating raw materials; (2) continuous nitrification; (3) aging; (4) diluting and layering; (5) neutralizing and layering; (6) crystallizing, separating and drying;
the whole production operation process of raw material pretreatment, continuous nitration, aging, dilution layering, neutralization layering, crystallization, separation and drying is dynamically and continuously carried out;
the raw material pretreatment in the step (1) is to add N-alkyl phthalimide into sulfuric acid according to a certain proportion, mix and dissolve the N-alkyl phthalimide and the sulfuric acid to obtain an N-alkyl phthalimide sulfuric acid solution; wherein the molar ratio of the N-alkyl phthalimide to the sulfuric acid is 1: 1-1: 10; the pretreatment temperature is 0-100 ℃;
the continuous nitration in the step (2) is to continuously pump the pretreated N-alkyl phthalimide sulfuric acid solution and nitric acid into a microchannel reactor according to a certain proportion to mix for nitration reaction; wherein the molar ratio of the N-alkyl phthalimide to the nitric acid is 1: 1-1: 10; the reaction temperature is 30-95 ℃; the mixing residence time of the N-alkyl phthalimide sulfuric acid solution and the nitric acid in the microchannel reactor is 5-500 s;
the aging in the step (3) is that the nitrified material flowing out of the microchannel reactor is continuously pumped into an aging reactor for aging, the aging temperature is controlled to be 30-200 ℃, the aged material continuously flows out of the aging reactor, and the retention time in the aging reactor is controlled to be 10-600 min;
the step (4) of dilution and layering is that the material flowing out of the aging reactor is continuously pumped into a dilution hydrolysis reactor, meanwhile, pure water is continuously pumped in proportion and mixed with the material to dilute the sulfuric acid to 10% -85% for hydrolysis, the hydrolyzed material continuously enters a first liquid separator for layering to form an upper organic phase and a lower acid solution, and the upper organic phase uninterruptedly flows out of the first liquid separator; wherein the temperature in the dilution hydrolysis reactor and the first liquid separator is controlled to be 20-100 ℃;
the step (5) of neutralization and stratification is that the upper organic phase flowing out through the first liquid separator is continuously pumped into a neutralization reactor, meanwhile, alkaline feed liquid is continuously pumped in proportion and mixed with the organic phase to adjust the pH value of the system to 6-8, the neutralized material continuously enters the second liquid separator to be stratified, an upper wastewater layer and a lower organic phase are formed, and the lower organic phase uninterruptedly flows out of the second liquid separator; wherein the temperature in the neutralization reactor and the second liquid separator is controlled to be 20-100 ℃;
and (3) the crystallization, separation and drying in the step (6) are that a crystallization solvent is added into a crystallization kettle, a lower organic phase flowing out of the crystallization kettle through a second liquid separator is continuously pumped into the crystallization kettle, solid-liquid separation is carried out after cooling crystallization, and the obtained solid is dried to prepare the N-alkyl-nitrophthalimide.
The alkyl of the raw material N-alkyl phthalimide can be any one of alkyl groups with 1-10 carbon atoms; specifically, the N-alkylphthalimide may be any one selected from N-methylphthalimide, N-ethylphthalimide, N-N-propylphthalimide, N-isopropylphthalimide, N-N-butylphthalimide, N-isobutylphthalimide, N-N-pentylphthalimide, or N-isopentylphthalimide.
In the invention, the sulfuric acid in the raw material pretreatment in the step (1) is concentrated sulfuric acid with the mass concentration of more than 90%, and the nitric acid in the continuous nitration in the step (2) is concentrated nitric acid with the mass concentration of more than 90%.
The molar ratio of the N-alkylphthalimide to the nitric acid in the continuous nitration in the step (2) is preferably 1: 1.05-1: 2.
The invention adopts the microchannel reactor to carry out the continuous nitration reaction of the N-alkyl phthalimide, and controls the mixing residence time of the N-alkyl phthalimide sulfuric acid solution and the nitric acid in the microchannel reactor by controlling the pumping speed of the raw materials according to the specification of the microchannel reactor, the conversion rate of the short nitration reaction is low when the mixing residence time is too long, and the production efficiency is reduced when the mixing residence time is too long. Preferably, the mixing residence time of the N-alkylphthalimide sulfuric acid solution and the nitric acid in the microchannel reactor is 10 s-100 s.
The temperature of the microchannel reactor which can accurately control the reaction is in the required range of the invention, the reaction by-products are increased when the temperature is too high, and the pressure of the microchannel reactor is increased when the temperature is higher than the boiling point of the concentrated nitric acid, thereby increasing the investment of equipment.
The invention carries out an aging step after the nitration reaction, further ensures the nitration reaction to be full and improves the reaction conversion rate. The material which finishes nitration reaction through the microchannel reactor is directly and continuously pumped into the aging reaction kettle for aging, the aged material can continuously flow out of the aging reaction kettle in an overflow mode, and the staying aging time of the material in the aging reaction kettle can be controlled by controlling the pumping speed of the material according to the specification of the aging reaction kettle so as to ensure that the reaction conversion rate can be effectively improved in the dynamic continuous production process. In the required aging temperature range, the nitration reaction can reach higher conversion rate, if the temperature is too high, reaction byproducts are increased, and the final conversion rate of a target product is reduced; preferably, the aging temperature is controlled to be 40-120 ℃.
According to research, the invention discovers that the dilution layering in the step (4) is additionally arranged, the concentration of sulfuric acid in the material after the aging reaction is diluted to be less than or equal to 85% by adopting pure water in a certain proportion, and a target product can be separated from the reaction system by water, so that the purification purpose is achieved; the higher the proportion of pure water is, the more beneficial the hydrolysis and precipitation of target products are, but a large amount of waste acid can be generated by excessive water, the energy consumption of acid liquor concentration is increased, and the cost is increased; preferably, the proportion of the pure water to the materials after the aging reaction is that the concentration of sulfuric acid is diluted to 30-60%, so that a target product can be more completely precipitated, and excessive waste acid cannot be generated.
Pure water and aged materials are continuously pumped into a dilution hydrolysis reactor according to a certain proportion for hydrolysis, the hydrolyzed materials are continuously fed into a first liquid separator for layering, the upper layer is a target product organic phase, the lower layer is waste acid, the feeding speed is controlled according to the specification of the liquid separator, the upper layer organic phase can continuously flow out of the liquid separator in an overflow mode, the layering in the liquid separator is maintained in a dynamic balance, and the production process is ensured to be carried out dynamically and continuously. The collected waste acid at the lower layer can be reused after being concentrated.
In the step (5), during the neutralization and delamination, residual acid liquor in the target product is more completely removed by using alkaline feed liquor for neutralization. The alkaline feed liquid is any one of sodium carbonate solution, sodium bicarbonate solution, potassium carbonate solution, potassium bicarbonate solution, sodium hydroxide solution, calcium hydroxide solution, methylamine solution, ethylamine solution, ethylenediamine solution or propylamine solution with the pH value of more than 7. The invention provides a preferable operation mode, a PH meter can be arranged at the outlet end of a neutralization reactor, and the PH meter and the feeding speed of alkaline feed liquid form linkage control, so that the proportion of the alkaline feed liquid can be controlled, and the pH of a final material system is 6-8.
Alkaline feed liquid and a target product organic phase are continuously pumped into a neutralization reactor according to a certain proportion for neutralization reaction, the neutralized material continuously enters a second liquid separator and then is layered, the upper layer is a wastewater layer, the lower layer is the target product organic phase, and the feeding speed and the discharging speed of the lower layer organic phase are controlled according to the specification of the liquid separator, so that the layering in the liquid separator is maintained in a dynamic balance, and the production process can be dynamically and continuously carried out. Recovering the upper wastewater layer.
The aging reactor, the dilution hydrolysis reactor and the neutralization reactor are reaction devices with mixing and heat-preserving functions; the reaction device with the mixing and heat-preserving functions can specifically select a stirred tank reactor, a stirred tubular reactor, a static mixer and the like; the invention can be realized by selecting different specifications and different types of reactors according to the actual production requirements.
The first liquid separator and the second liquid separator are devices with liquid separation functions, and specifically, liquid separation columns or liquid separation towers and the like can be selected; according to actual production needs, dispensers of different specifications and different types can be selected to realize the invention.
The crystallization solvent in the step (6) is selected from one or more of methyl acetate, ethyl acetate, butyl acetate, methanol, ethanol, isopropanol, acetone and butanone.
According to the actual production needs, a plurality of crystallization kettles can be arranged to realize the continuous operation from crystallization to subsequent solid-liquid separation and drying steps.
In the solid-liquid separation step after crystallization, equipment with a solid-liquid separation function such as a centrifuge, a plate-and-frame filter or a suction filtration tank can be selected according to actual production requirements to carry out solid-liquid separation operation.
The drying step can be carried out by selecting a rotary drum dryer, a double-cone dryer, a fluidized bed, a boiling dryer, a spiral dryer or other equipment with equivalent effect according to the actual production requirement.
Compared with the prior art, the invention has the following beneficial effects:
the continuous industrial production method of the N-alkyl-nitrophthalimide adopts the microchannel reactor to carry out continuous nitration reaction, and does not need to use an organic extractant for extraction in the post-treatment process, so that the operation is simple, the method is safe and environment-friendly, and the prepared product has high yield and high purity (the product purity is more than or equal to 99.5%); the whole production process of the raw material reaction and the post-treatment operation is dynamically and continuously carried out, the production efficiency is high, the labor cost is greatly reduced, the quality of the final product is stable and controllable, and large-scale industrial production can be realized.
Drawings
FIG. 1 is a schematic flow chart of a continuous industrial production method of N-alkyl-nitrophthalimide according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.
The reagents used in the examples of the present invention and comparative examples are commercially available, but are not limited to these materials.
The product purity test method comprises the following steps: the invention adopts gas chromatography to test the product concentration.
And (3) testing conditions are as follows:
a chromatographic column: HP-5, 30 m.times.0.32 mm.times.0.25 μm;
solvent: dichloromethane;
concentration: 2 mg/ml;
sample inlet temperature: 280 ℃;
the split ratio is 30: 1;
temperature of the column box: the initial temperature is 100 ℃, the retention time is 1min, the temperature is raised to 260 ℃ at the temperature raising speed of 15 ℃/min, and the retention time is 1 min;
detector temperature: 280 ℃; air: 400 ml/min; h2: 40 ml/min; tail gas: 30 ml/min;
column flow rate: 1.4 ml/min.
Example 1
(1) Pretreatment of raw materials: putting 320kg of N-methylphthalimide and 300kg of concentrated sulfuric acid (the mass fraction is 98%) into a preparation kettle, mixing and dissolving, and then heating to 40 ℃ for pretreatment to obtain an N-methylphthalimide sulfuric acid solution; wherein the molar ratio of the N-methylphthalimide to the sulfuric acid is 1: 1.5;
(2) continuous nitrification: continuously pumping the pretreated N-methylphthalimide sulfuric acid solution into a microchannel reactor at the flow rate of 5kg/min and the flow rate of concentrated nitric acid (the mass fraction is 95%) at the flow rate of 5.3kg/min for mixing for nitration reaction; wherein the molar ratio of the N-alkyl phthalimide to the nitric acid is 1:5, the reaction temperature is 90 ℃, and the mixing residence time of the N-methyl phthalimide sulfuric acid solution and the concentrated nitric acid in the microchannel reactor is 60 s;
(3) aging: continuously pumping the nitrified material flowing out of the microchannel reactor into an aging reactor at the flow rate of 10.3kg/min for aging, controlling the aging temperature to be 90 ℃, and enabling the aged material to continuously flow out of the aging reactor; the retention time of the materials in the aging reactor is 120 min;
(4) diluting and layering: continuously pumping the material flowing out of the aging reactor into a dilution hydrolysis reactor at the flow rate of 10.3kg/min, continuously pumping pure water at the flow rate of 5.6kg/min, mixing with the material to dilute the sulfuric acid to 60% for hydrolysis, keeping the temperature in the kettle at 90 ℃, after the hydrolysis is finished, continuously feeding the material into a first liquid separation column, keeping the temperature in the liquid separation column at 90 ℃, layering the material into an upper organic phase and a lower acid solution, uninterruptedly overflowing the upper organic phase from the first liquid separation column, collecting the lower acid solution, and concentrating the lower acid solution for reuse;
(5) neutralizing and layering: continuously pumping the upper organic phase flowing out of the first liquid separation column into a static mixer at the flow rate of 3.5kg/min, simultaneously continuously pumping 10% sodium carbonate solution according to a certain proportion, keeping the temperature in the static mixer at 90 ℃, arranging a PH meter at the outlet end of the static mixer, forming linkage control with the pumping speed of the sodium carbonate solution, controlling the flow rate of the sodium carbonate solution to ensure that the pH of the material flowing out of the outlet end of the static mixer is 7.5, continuously feeding the neutralized material into a second liquid separation column, keeping the temperature in the liquid separation column at 90 ℃, layering into an upper waste water layer and a lower organic phase, uninterruptedly flowing out of the second liquid separation column, and simultaneously recovering the upper waste water layer;
(6) crystallization, separation and drying: adding 1200kg of methyl acetate into a crystallization kettle, continuously pumping a lower-layer organic phase flowing out through a second liquid separation column into the crystallization kettle for cooling crystallization, cooling to room temperature, centrifuging by using a centrifugal machine to separate solid from liquid, and drying the obtained solid wet material by using a double-cone dryer to obtain N-methyl-nitrophthalimide; the yield was 95.9% and the purity was 99.6%.
Example 2
(1) Pretreatment of raw materials: putting 320kg of N-isobutyl phthalimide and 640kg of concentrated sulfuric acid (the mass fraction is 98%) into a preparation kettle, and mixing and dissolving to obtain an N-isobutyl phthalimide sulfuric acid solution; wherein the molar ratio of the N-isobutyl phthalimide to the sulfuric acid is 1: 4;
(2) continuous nitrification: continuously pumping the pretreated N-isobutyl phthalimide sulfuric acid solution into a microchannel reactor at a flow rate of 5.1kg/min and concentrated nitric acid (the mass fraction is 95%) at a flow rate of 1.1kg/min for mixing for nitration reaction; wherein the molar ratio of the N-isobutylphthalimide to the nitric acid is 1:2, the reaction temperature is 70 ℃, and the mixing residence time of the N-isobutylphthalimide sulfuric acid solution and the concentrated nitric acid in the microchannel reactor is 400 s;
(3) aging: continuously pumping the nitrified material flowing out of the microchannel reactor into an aging reactor at the flow rate of 6.2kg/min for aging, controlling the aging temperature to be 70 ℃, and enabling the aged material to continuously flow out of the aging reactor; the retention time of the materials in the aging reactor is 240 min;
(4) diluting and layering: continuously pumping the material flowing out of the aging reactor into a dilution hydrolysis reactor at the flow rate of 6.2kg/min, continuously pumping pure water at the flow rate of 2.27kg/min, mixing with the material to dilute the sulfuric acid to 60% for hydrolysis, keeping the temperature in the kettle at 70 ℃, after the hydrolysis is finished, continuously feeding the material into a first liquid separation column, keeping the temperature in the liquid separation column at 70 ℃, layering into an upper organic phase and a lower acid solution, uninterruptedly overflowing the upper organic phase from the first liquid separation column, collecting the lower acid solution, and concentrating the lower acid solution for reuse;
(5) neutralizing and layering: continuously pumping the upper organic phase flowing out of the first liquid separation column into a static mixer at the flow rate of 2.08kg/min, simultaneously continuously pumping 10% sodium hydroxide solution according to a certain proportion, keeping the temperature in the static mixer at 90 ℃, arranging a pH meter at the outlet end of the static mixer, forming linkage control with the pumping speed of the sodium hydroxide solution, controlling the flow rate of the sodium hydroxide solution to ensure that the pH of the material flowing out of the outlet end of the static mixer is 7.5, continuously feeding the neutralized material into a second liquid separation column, keeping the temperature in the liquid separation column at 70 ℃, layering into an upper wastewater layer and a lower organic phase, uninterruptedly flowing out of the second liquid separation column, and simultaneously recovering the upper wastewater layer;
(6) crystallization, separation and drying: adding 1200kg of ethyl acetate into a crystallization kettle, continuously pumping a lower-layer organic phase flowing out through a second liquid separation column into the crystallization kettle for cooling crystallization, cooling to room temperature, centrifuging by using a centrifugal machine to separate solid from liquid, and drying the obtained solid wet material by using a double-cone dryer to obtain N-isobutyl-nitrophthalimide; the yield was 95.0% and the purity was 99.8%.
Example 3
(1) Pretreatment of raw materials: putting 320kg of N-isopropylphthalimide and 550kg of concentrated sulfuric acid (the mass fraction is 98%) into a preparation kettle, mixing and dissolving, and then heating to 60 ℃ for pretreatment to obtain an N-isopropylphthalimide sulfuric acid solution; wherein the molar ratio of the N-isopropylphthalimide to the sulfuric acid is 1: 3.3;
(2) continuous nitrification: continuously pumping the pretreated N-isopropylphthalimide sulfuric acid solution into a microchannel reactor at a flow rate of 5.1kg/min and concentrated nitric acid (mass fraction is 95%) at a flow rate of 0.72kg/min for mixing for nitration reaction; wherein the molar ratio of the N-isopropylphthalimide to the nitric acid is 1:1.1, the reaction temperature is 80 ℃, and the mixing residence time of the N-isopropylphthalimide sulfuric acid solution and the concentrated nitric acid in the microchannel reactor is 10 s;
(3) aging: continuously pumping the nitrified material flowing out of the microchannel reactor into an aging reactor at the flow rate of 5.82kg/min for aging, controlling the aging temperature to be 80 ℃, and enabling the aged material to continuously flow out of the aging reactor; the retention time of the materials in the aging reactor is 240 min;
(4) diluting and layering: continuously pumping the material flowing out of the aging reactor into a dilution hydrolysis reactor at the flow rate of 5.82kg/min, continuously pumping pure water at the flow rate of 3.2kg/min, mixing with the material to dilute the sulfuric acid to 50% for hydrolysis, keeping the temperature in the kettle at 80 ℃, after the hydrolysis is finished, continuously feeding the material into a first liquid separation column, keeping the temperature in the liquid separation column at 80 ℃, layering into an upper organic phase and a lower acid solution, uninterruptedly overflowing the upper organic phase from the first liquid separation column, collecting the lower acid solution, and concentrating the lower acid solution for reuse;
(5) neutralizing and layering: continuously pumping the upper organic phase flowing out of the first liquid separation column into a static mixer at the flow rate of 1.95kg/min, simultaneously continuously pumping 5% potassium hydroxide solution according to a certain proportion, keeping the temperature in the static mixer at 80 ℃, arranging a pH meter at the outlet end of the static mixer, forming linkage control with the pumping speed of the potassium hydroxide solution, controlling the flow rate of the potassium hydroxide solution to ensure that the pH of the material flowing out of the outlet end of the static mixer is 7.5, continuously feeding the neutralized material into a second liquid separation column, keeping the temperature in the liquid separation column at 80 ℃, layering into an upper wastewater layer and a lower organic phase, uninterruptedly flowing out of the second liquid separation column, and simultaneously recovering the upper wastewater layer;
(6) crystallization, separation and drying: adding 1200kg of ethanol into a crystallization kettle, continuously pumping a lower-layer organic phase flowing out through a second liquid separation column into the crystallization kettle for cooling crystallization, cooling to room temperature, centrifuging by using a centrifugal machine to separate solid from liquid, and drying the obtained solid wet material by using a double-cone dryer to obtain N-isopropyl-nitrophthalimide; the yield was 97.0% and the purity was 99.6%.
Example 4
Example 4 differs from example 3 only in that in the dilution and stratification in step (4), pure water is added in such a proportion that the sulfuric acid concentration in the material is diluted to 70%, and the specific steps are as follows:
(1) pretreatment of raw materials: putting 320kg of N-isopropylphthalimide and 550kg of concentrated sulfuric acid (the mass fraction is 98%) into a preparation kettle, mixing and dissolving, and then heating to 60 ℃ for pretreatment to obtain an N-isopropylphthalimide sulfuric acid solution; wherein the molar ratio of the N-isopropylphthalimide to the sulfuric acid is 1: 3.3;
(2) continuous nitrification: continuously pumping the pretreated N-isopropylphthalimide sulfuric acid solution into a microchannel reactor at a flow rate of 5.1kg/min and concentrated nitric acid (mass fraction is 95%) at a flow rate of 0.72kg/min for mixing for nitration reaction; wherein the molar ratio of the N-isopropylphthalimide to the nitric acid is 1:1.1, the reaction temperature is 80 ℃, and the mixing residence time of the N-isopropylphthalimide sulfuric acid solution and the concentrated nitric acid in the microchannel reactor is 10 s;
(3) aging: continuously pumping the nitrified material flowing out of the microchannel reactor into an aging reactor at the flow rate of 5.82kg/min for aging, controlling the aging temperature to be 80 ℃, and enabling the aged material to continuously flow out of the aging reactor; the retention time of the materials in the aging reactor is 240 min;
(4) diluting and layering: continuously pumping the material flowing out of the aging reactor into a dilution hydrolysis reactor at the flow rate of 5.82kg/min, continuously pumping pure water at the flow rate of 1.38kg/min, mixing with the material to dilute the sulfuric acid to 70% for hydrolysis, keeping the temperature in the kettle at 80 ℃, after the hydrolysis is finished, continuously feeding the material into a first liquid separation column, keeping the temperature in the liquid separation column at 80 ℃, layering into an upper organic phase and a lower acid solution, uninterruptedly overflowing the upper organic phase from the first liquid separation column, collecting the lower acid solution, and concentrating the lower acid solution for reuse;
(5) neutralizing and layering: continuously pumping the upper organic phase flowing out of the first liquid separation column into a static mixer at the flow rate of 1.95kg/min, simultaneously continuously pumping 5% potassium hydroxide solution according to a certain proportion, keeping the temperature in the static mixer at 80 ℃, arranging a pH meter at the outlet end of the static mixer, forming linkage control with the pumping speed of the potassium hydroxide solution, controlling the flow rate of the potassium hydroxide solution to ensure that the pH of the material flowing out of the outlet end of the static mixer is 7.5, continuously feeding the neutralized material into a second liquid separation column, keeping the temperature in the liquid separation column at 80 ℃, layering into an upper wastewater layer and a lower organic phase, uninterruptedly flowing out of the second liquid separation column, and simultaneously recovering the upper wastewater layer;
(6) crystallization, separation and drying: adding 1200kg of ethanol into a crystallization kettle, continuously pumping a lower-layer organic phase flowing out through a second liquid separation column into the crystallization kettle for cooling crystallization, cooling to room temperature, centrifuging by using a centrifugal machine to separate solid from liquid, and drying the obtained solid wet material by using a double-cone dryer to obtain N-isopropyl-nitrophthalimide; the yield was 90.0% and the purity was 99.6%.
Example 5
(1) Pretreatment of raw materials: putting 320kg of N-ethyl phthalimide and 1886kg of sulfuric acid (the mass fraction is 95%) into a preparation kettle, mixing and dissolving, and then heating to 40 ℃ for pretreatment to obtain an N-ethyl phthalimide sulfuric acid solution; wherein the molar ratio of the N-ethylphthalimide to the sulfuric acid is 1: 10;
(2) continuous nitrification: continuously pumping the pretreated N-ethyl phthalimide sulfuric acid solution into a microchannel reactor at a flow rate of 5.1kg/min and concentrated nitric acid (mass fraction is 95%) at a flow rate of 0.56kg/min for mixing for nitration reaction; wherein the molar ratio of the N-ethyl phthalimide to the nitric acid is 1:2, the reaction temperature is 80 ℃, and the mixing residence time of the N-ethyl phthalimide sulfuric acid solution and the concentrated nitric acid in the microchannel reactor is 300 s;
(3) aging: continuously pumping the nitrified material flowing out of the microchannel reactor into an aging reactor at the flow rate of 5.66kg/min for aging, controlling the aging temperature to be 80 ℃, and enabling the aged material to continuously flow out of the aging reactor; the retention time of the materials in the aging reactor is 240 min;
(4) diluting and layering: continuously pumping the material flowing out of the aging reactor into a dilution hydrolysis reactor at the flow rate of 5.66kg/min, continuously pumping pure water at the flow rate of 10.17kg/min, mixing with the material to dilute the sulfuric acid to 30% for hydrolysis, keeping the temperature in the kettle at 80 ℃, after the hydrolysis is finished, continuously feeding the material into a first liquid separation column, keeping the temperature in the liquid separation column at 80 ℃, layering into an upper organic phase and a lower acid solution, uninterruptedly overflowing the upper organic phase from the first liquid separation column, collecting the lower acid solution, and concentrating the lower acid solution for reuse;
(5) neutralizing and layering: continuously pumping the upper organic phase flowing out of the first liquid separation column into a static mixer at the flow rate of 0.8kg/min, simultaneously continuously pumping 5% potassium hydroxide solution according to a certain proportion, keeping the temperature in the static mixer at 80 ℃, arranging a pH meter at the outlet end of the static mixer, forming linkage control with the pumping speed of the potassium hydroxide solution, controlling the flow rate of the potassium hydroxide solution to ensure that the pH of the material flowing out of the outlet end of the static mixer is 7.5, continuously feeding the neutralized material into a second liquid separation column, keeping the temperature in the liquid separation column at 80 ℃, layering into an upper wastewater layer and a lower organic phase, uninterruptedly flowing out of the second liquid separation column, and simultaneously recovering the upper wastewater layer;
(6) crystallization, separation and drying: adding 1200kg of ethanol into a crystallization kettle, continuously pumping a lower-layer organic phase flowing out through a second liquid separation column into the crystallization kettle for cooling crystallization, cooling to room temperature, centrifuging by using a centrifugal machine to separate solid from liquid, and drying the obtained solid wet material by using a double-cone dryer to obtain N-ethyl-nitrophthalimide; the yield was 96.0% and the purity was 99.7%.
Example 6
(1) Pretreatment of raw materials: putting 320kg of N-isoamyl phthalimide and 608kg of sulfuric acid (the mass fraction is 95%) into a preparation kettle, mixing and dissolving, and then heating to 40 ℃ for pretreatment to obtain an N-isoamyl phthalimide sulfuric acid solution; wherein the molar ratio of the N-isoamyl phthalimide to the sulfuric acid is 1: 4;
(2) continuous nitrification: continuously pumping the pretreated N-isoamyl phthalimide sulfuric acid solution into a microchannel reactor at a flow rate of 5.1kg/min and concentrated nitric acid (mass fraction is 95%) at a flow rate of 2.69kg/min for mixing for nitration reaction; wherein the molar ratio of the N-isoamyl phthalimide to the nitric acid is 1:5, the reaction temperature is 75 ℃, and the mixing residence time of the N-isoamyl phthalimide sulfuric acid solution and the concentrated nitric acid in the microchannel reactor is 300 s;
(3) aging: continuously pumping the nitrified material flowing out of the microchannel reactor into an aging reactor at the flow rate of 7.79kg/min for aging, controlling the aging temperature to be 75 ℃, and enabling the aged material to continuously flow out of the aging reactor; the retention time of the materials in the aging reactor is 240 min;
(4) diluting and layering: continuously pumping the material flowing out of the aging reactor into a dilution hydrolysis reactor at the flow rate of 7.79kg/min, continuously pumping pure water at the flow rate of 7.79kg/min, mixing the pure water with the material to dilute the sulfuric acid to 30% for hydrolysis, keeping the temperature in the kettle at 60 ℃, after the hydrolysis is finished, continuously feeding the material into a first liquid separation column, keeping the temperature in the liquid separation column at 60 ℃, layering the material into an upper organic phase and a lower acid solution, uninterruptedly overflowing the upper organic phase from the first liquid separation column, collecting the lower acid solution, and concentrating the lower acid solution for reuse;
(5) neutralizing and layering: continuously pumping the upper organic phase flowing out of the first liquid separation column into a static mixer at the flow rate of 1.8kg/min, simultaneously continuously pumping 5% potassium hydroxide solution according to a certain proportion, keeping the temperature in the static mixer at 60 ℃, arranging a pH meter at the outlet end of the static mixer, forming linkage control with the pumping speed of the potassium hydroxide solution, controlling the flow rate of the potassium hydroxide solution to ensure that the pH of the material flowing out of the outlet end of the static mixer is 7.5, continuously feeding the neutralized material into a second liquid separation column, keeping the temperature in the liquid separation column at 60 ℃, layering into an upper wastewater layer and a lower organic phase, uninterruptedly flowing out of the second liquid separation column, and simultaneously recovering the upper wastewater layer;
(6) crystallization, separation and drying: adding 1200kg of ethanol into a crystallization kettle, continuously pumping a lower-layer organic phase flowing out through a second liquid separation column into the crystallization kettle for cooling crystallization, cooling to room temperature, centrifuging by using a centrifugal machine to separate solid from liquid, and drying the obtained solid wet material by using a double-cone dryer to obtain N-isoamyl-nitrophthalimide; the yield was 96.8% and the purity was 99.6%.
It can be seen from the above examples that the continuous industrial production method of N-alkyl-nitrophthalimide of the present invention can realize the dynamic continuous operation of the whole production process from the raw material reaction and the post-treatment operation, after the continuous nitration reaction, the product yield and purity can be effectively improved by dynamically and continuously carrying out the post-treatment steps of aging, dilution layering, neutralization layering, crystallization, separation and drying, the purity of the prepared product reaches 99.5% and above, and the product can be directly used in the next reaction; meanwhile, the stable and controllable product quality can be ensured.
Claims (9)
1. A continuous industrial production method of N-alkyl-nitrophthalimide is characterized by comprising the following steps: (1) pretreating raw materials; (2) continuous nitrification; (3) aging; (4) diluting and layering; (5) neutralizing and layering; (6) crystallizing, separating and drying;
the whole production operation process of raw material pretreatment, continuous nitration, aging, dilution layering, neutralization layering, crystallization, separation and drying is dynamically and continuously carried out;
the raw material pretreatment in the step (1) is to add N-alkyl phthalimide into sulfuric acid according to a certain proportion, mix and dissolve the N-alkyl phthalimide and the sulfuric acid to obtain an N-alkyl phthalimide sulfuric acid solution; wherein the molar ratio of the N-alkyl phthalimide to the sulfuric acid is 1: 1-1: 10; the pretreatment temperature is 0-100 ℃;
the continuous nitration in the step (2) is to continuously pump the pretreated N-alkyl phthalimide sulfuric acid solution and nitric acid into a microchannel reactor according to a certain proportion to mix for nitration reaction; wherein the molar ratio of the N-alkyl phthalimide to the nitric acid is 1: 1-1: 10; the reaction temperature is 30-95 ℃; the mixing residence time of the N-alkyl phthalimide sulfuric acid solution and the nitric acid in the microchannel reactor is 5-500 s;
the aging in the step (3) is that the nitrified material flowing out of the microchannel reactor is continuously pumped into an aging reactor for aging, the aging temperature is controlled to be 30-200 ℃, the aged material continuously flows out of the aging reactor, and the retention time in the aging reactor is controlled to be 10-600 min;
the step (4) of dilution and layering is that the material flowing out of the aging reactor is continuously pumped into a dilution hydrolysis reactor, meanwhile, pure water is continuously pumped in proportion and mixed with the material to dilute the sulfuric acid to 10% -85% for hydrolysis, the hydrolyzed material continuously enters a first liquid separator for layering to form an upper organic phase and a lower acid solution, and the upper organic phase uninterruptedly flows out of the first liquid separator; wherein the temperature in the dilution hydrolysis reactor and the first liquid separator is controlled to be 20-100 ℃;
the step (5) of neutralization and stratification is that the upper organic phase flowing out through the first liquid separator is continuously pumped into a neutralization reactor, meanwhile, alkaline feed liquid is continuously pumped in proportion and mixed with the organic phase to adjust the pH value of the system to 6-8, the neutralized material continuously enters the second liquid separator to be stratified, an upper wastewater layer and a lower organic phase are formed, and the lower organic phase uninterruptedly flows out of the second liquid separator; wherein the temperature in the neutralization reactor and the second liquid separator is controlled to be 20-100 ℃;
and (3) the crystallization, separation and drying in the step (6) are that a crystallization solvent is added into a crystallization kettle, a lower organic phase flowing out of the crystallization kettle through a second liquid separator is continuously pumped into the crystallization kettle, solid-liquid separation is carried out after cooling crystallization, and the obtained solid is dried to prepare the N-alkyl-nitrophthalimide.
2. The continuous industrial production method of N-alkyl-nitrophthalimide as claimed in claim 1, wherein the alkyl group of N-alkylphthalimide in step (1) is selected from any one of alkyl groups having 1 to 10 carbon atoms; preferably, the N-alkylphthalimide is selected from any one of N-methylphthalimide, N-ethylphthalimide, N-N-propylphthalimide, N-isopropylphthalimide, N-N-butylphthalimide, N-isobutylphthalimide, N-N-pentylphthalimide or N-isopentylphthalimide.
3. The continuous industrial production method of N-alkyl-nitrophthalimide according to claim 1, wherein said sulfuric acid in step (1) is concentrated sulfuric acid with a mass concentration of more than 90%; the nitric acid in the step (2) is concentrated nitric acid with the mass concentration of more than 90%.
4. The continuous industrial production method of N-alkyl-nitrophthalimide according to claim 1, wherein the molar ratio of N-alkylphthalimide to nitric acid in step (2) is 1:1.05 to 1: 2.
5. The continuous industrial production method of N-alkyl-nitrophthalimide according to claim 1, wherein the mixing residence time of the concentrated sulfuric acid solution of N-alkylphthalimide and the concentrated nitric acid in the microchannel reactor in step (2) is 10s to 100 s.
6. The continuous industrial process for the production of N-alkyl-nitrophthalimide as claimed in claim 1, wherein said aging temperature in step (3) is from 40 ℃ to 120 ℃.
7. The continuous industrial production method of N-alkyl-nitrophthalimide as claimed in claim 1, wherein pure water is pumped in step (4) to dilute the sulfuric acid concentration of the material to 30% to 60%.
8. The continuous industrial production method of N-alkyl-nitrophthalimide as claimed in claim 1, wherein said alkaline solution in step (5) is selected from any one of sodium carbonate solution, sodium bicarbonate solution, potassium carbonate solution, potassium bicarbonate solution, sodium hydroxide solution, calcium hydroxide solution, methylamine solution, ethylamine solution, ethylenediamine solution and propylamine solution with pH greater than 7.
9. The continuous industrial production method of N-alkyl-nitrophthalimide as claimed in claim 1, wherein said crystallization solvent in step (6) is selected from one or more of methyl acetate, ethyl acetate, butyl acetate, methanol, ethanol, isopropanol, acetone or butanone.
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| CN115138326A (en) * | 2022-07-04 | 2022-10-04 | 山东安诺其化工技术研究有限公司 | Device and process for continuously producing monopersulfate composite salt |
| CN114920685B (en) * | 2022-05-23 | 2024-07-02 | 上海华谊（集团）公司 | Continuous synthesis method of N-alkyl-4-nitrophthalimide |
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| WO2020131258A1 (en) * | 2018-12-21 | 2020-06-25 | Sabic Global Technologies B.V. | Method for the manufacture of 4-nitro-n-(c1-8 alkyl)phthalimide |
| CN113354541A (en) * | 2021-06-03 | 2021-09-07 | 天津泰研科技发展有限公司 | Method for cleanly producing 2, 4-dinitro benzene chloride |
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| CN109305933A (en) * | 2018-10-30 | 2019-02-05 | 浙江万丰化工有限公司 | A method of preparing N- alkyl -4- nitrophthalimide |
| WO2020131258A1 (en) * | 2018-12-21 | 2020-06-25 | Sabic Global Technologies B.V. | Method for the manufacture of 4-nitro-n-(c1-8 alkyl)phthalimide |
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| CN114920685A (en) * | 2022-05-23 | 2022-08-19 | 上海华谊（集团）公司 | Continuous synthesis method of N-alkyl-4-nitrophthalimide |
| CN114920685B (en) * | 2022-05-23 | 2024-07-02 | 上海华谊（集团）公司 | Continuous synthesis method of N-alkyl-4-nitrophthalimide |
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