CN114671808A - Preparation method of caprolactam - Google Patents
Preparation method of caprolactam Download PDFInfo
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- CN114671808A CN114671808A CN202210458283.9A CN202210458283A CN114671808A CN 114671808 A CN114671808 A CN 114671808A CN 202210458283 A CN202210458283 A CN 202210458283A CN 114671808 A CN114671808 A CN 114671808A
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- caprolactam
- cyclohexanone
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- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 title claims abstract description 144
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- VEZUQRBDRNJBJY-UHFFFAOYSA-N cyclohexanone oxime Chemical compound ON=C1CCCCC1 VEZUQRBDRNJBJY-UHFFFAOYSA-N 0.000 claims abstract description 96
- 238000006243 chemical reaction Methods 0.000 claims abstract description 92
- 238000006462 rearrangement reaction Methods 0.000 claims abstract description 49
- 238000006146 oximation reaction Methods 0.000 claims abstract description 36
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 28
- 238000006386 neutralization reaction Methods 0.000 claims abstract description 26
- 230000008569 process Effects 0.000 claims abstract description 24
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 16
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 16
- 238000006237 Beckmann rearrangement reaction Methods 0.000 claims abstract description 11
- 239000012442 inert solvent Substances 0.000 claims abstract description 11
- 239000003960 organic solvent Substances 0.000 claims abstract description 9
- 230000008707 rearrangement Effects 0.000 claims abstract description 8
- 238000004064 recycling Methods 0.000 claims abstract description 4
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 claims description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 36
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 35
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 30
- 239000003054 catalyst Substances 0.000 claims description 23
- 229910021529 ammonia Inorganic materials 0.000 claims description 16
- 239000007795 chemical reaction product Substances 0.000 claims description 14
- 230000035484 reaction time Effects 0.000 claims description 11
- HIFJUMGIHIZEPX-UHFFFAOYSA-N sulfuric acid;sulfur trioxide Chemical compound O=S(=O)=O.OS(O)(=O)=O HIFJUMGIHIZEPX-UHFFFAOYSA-N 0.000 claims description 8
- 238000000926 separation method Methods 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 6
- 239000002994 raw material Substances 0.000 claims description 4
- 230000009471 action Effects 0.000 claims description 3
- 230000003197 catalytic effect Effects 0.000 claims description 3
- 150000002576 ketones Chemical class 0.000 claims description 3
- 239000002904 solvent Substances 0.000 abstract description 15
- 238000004821 distillation Methods 0.000 abstract description 4
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 230000007547 defect Effects 0.000 abstract description 3
- 238000007210 heterogeneous catalysis Methods 0.000 abstract description 2
- 230000036632 reaction speed Effects 0.000 abstract description 2
- 239000012071 phase Substances 0.000 description 66
- 239000000243 solution Substances 0.000 description 45
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 36
- 238000005086 pumping Methods 0.000 description 32
- 238000002156 mixing Methods 0.000 description 30
- KVZJLSYJROEPSQ-UHFFFAOYSA-N 1,2-dimethylcyclohexane Chemical compound CC1CCCCC1C KVZJLSYJROEPSQ-UHFFFAOYSA-N 0.000 description 18
- 239000000725 suspension Substances 0.000 description 13
- 239000000047 product Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 4
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 4
- 235000011130 ammonium sulphate Nutrition 0.000 description 4
- 239000012045 crude solution Substances 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000004321 preservation Methods 0.000 description 4
- 238000007670 refining Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 150000002923 oximes Chemical class 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- AXTGDCSMTYGJND-UHFFFAOYSA-N 1-dodecylazepan-2-one Chemical compound CCCCCCCCCCCCN1CCCCCC1=O AXTGDCSMTYGJND-UHFFFAOYSA-N 0.000 description 1
- SLXKOJJOQWFEFD-UHFFFAOYSA-N 6-aminohexanoic acid Chemical compound NCCCCCC(O)=O SLXKOJJOQWFEFD-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 206010024769 Local reaction Diseases 0.000 description 1
- 229920002292 Nylon 6 Polymers 0.000 description 1
- 230000001476 alcoholic effect Effects 0.000 description 1
- 150000001408 amides Chemical class 0.000 description 1
- 229960002684 aminocaproic acid Drugs 0.000 description 1
- 229940127218 antiplatelet drug Drugs 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 229920006351 engineering plastic Polymers 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229960003639 laurocapram Drugs 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 239000000106 platelet aggregation inhibitor Substances 0.000 description 1
- 238000010517 secondary reaction Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
- C07D223/02—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings
- C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D223/08—Oxygen atoms
- C07D223/10—Oxygen atoms attached in position 2
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D201/00—Preparation, separation, purification or stabilisation of unsubstituted lactams
- C07D201/02—Preparation of lactams
- C07D201/04—Preparation of lactams from or via oximes by Beckmann rearrangement
- C07D201/06—Preparation of lactams from or via oximes by Beckmann rearrangement from ketones by simultaneous oxime formation and rearrangement
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Other In-Based Heterocyclic Compounds (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention belongs to the technical field of petrochemical industry, and particularly discloses a preparation method of caprolactam, wherein cyclohexanone oxime generated in a heterogeneous catalysis oximation reaction is continuously dissolved in an inert solvent of the oximation reaction and enters subsequent rearrangement in a solution mode, Beckmann rearrangement reaction is carried out to generate caprolactam sulfonate, the caprolactam sulfonate is naturally separated from the inert organic solvent, the obtained caprolactam sulfonate is subjected to neutralization reaction with ammonia water in a third microreactor system to generate caprolactam, the defect that the cyclohexanone oxime is easy to solidify and block a pipeline in the prior art is overcome, the initial reaction temperature of the Beckmann rearrangement reaction is further reduced, the inert organic solvent used in the oximation reaction is also a good solvent in the rearrangement reaction process, the solvent is naturally layered with a product and separated after the rearrangement reaction is finished, the solvent distillation process of the prior art is omitted, and the solvent can be returned to an ammoximation reaction system for recycling, reduce the energy consumption of the system, improve the reaction speed and improve the product quality.
Description
Technical Field
The invention belongs to the technical field of petrochemical industry, and particularly discloses a preparation method of caprolactam.
Background
Caprolactam is an important organic chemical raw material, is mainly used for producing nylon-6 fibers and engineering plastics, can also be used for producing antiplatelet drugs 6-aminocaproic acid, laurocapram and the like, has wide application and wide development prospect, and is an isomer of caprolactam, an important intermediate for producing caprolactam, and 90 percent of the caprolactam all over the world is prepared from the cyclohexanone oxime through Beckmann rearrangement.
Chinese patent CN100386307 proposes that under the condition of inert solvent and catalyst, ketone, hydrogen peroxide and ammonia are subjected to heterogeneous catalytic oximation reaction to generate ketoxime, the water phase product of oximation reaction is extracted by inert solvent, the extraction phase is mixed with the organic phase product of oximation reaction to obtain the inert solvent solution of ketoxime, the solution is subjected to heterogeneous Beckmann rearrangement reaction to generate amide under the action of oleum, the method still needs to extract the solution containing cyclohexanone oxime by inert organic solvent to obtain the extraction phase containing cyclohexanone oxime and the raffinate phase containing oximation catalyst and water, the extraction phase is subjected to Beckmann rearrangement reaction with oleum, and then the product of Beckmann rearrangement reaction and ammonia are subjected to neutralization reaction, cyclohexanone oxime enters subsequent rearrangement in solution mode rather than melting mode, thus overcoming the defect of easy blockage of the existing process, the operation difficulty is reduced, the stable and continuous operation of the device is ensured, meanwhile, the flexible adjustment of the Beckmann rearrangement reaction temperature is possible, the problems that the mass transfer effect is poor and the local reaction temperature is mutated when pure materials react with fuming sulfuric acid are solved through the solvent rearrangement, the reaction quality can be improved, the sulfuric acid consumption and byproducts are further reduced, the reaction time is short, the reaction temperature is easy to control, the reaction condition is mild, the yield and the conversion rate are high and the like are advantageous for the continuous production in the industrial production, but the defects and the problems that the production efficiency is reduced, the energy utilization rate is low, the large-scale industrialization is difficult and the like exist.
The micro-reactor has small channel size and channel diversity, fluid flows in the channels and required reaction occurs in the channels, and the micro-structured chemical equipment has very large specific surface area/volume ratio, so that great mass and heat transfer capacity is generated, and the micro-reactor has the fundamental advantages of great heat exchange efficiency and mixing efficiency, can accurately control reaction temperature and instantly mix reaction materials according to accurate proportion, and are key factors for improving yield, selectivity and safety and improving product quality.
Disclosure of Invention
In order to solve the problems in the background art, the invention discloses a caprolactam preparation method, wherein a microreactor system is adopted in the full series of ammoximation, cyclohexanone-oxime rearrangement reaction and neutralization reaction, the reaction temperature is stably controlled, the product quality is improved, the production cost is reduced, and the method is green, environment-friendly and efficient.
In order to achieve the purpose, the invention adopts the following technical scheme:
a process for producing caprolactam comprising the steps of: under the condition of inert solvent, cyclohexanone, hydrogen peroxide, catalyst and ammonia are subjected to heterogeneous catalytic oximation reaction in a first micro-reactor system or a kettle type reactor to generate cyclohexanone oxime, the obtained cyclohexanone oxime solution is subjected to Beckmann rearrangement reaction in a second micro-reactor system under the action of fuming sulfuric acid to generate caprolactam sulfonate, a reaction product is naturally separated from an inert organic solvent to obtain a caprolactam sulfonate water phase, the caprolactam sulfonate water phase is subjected to neutralization reaction with ammonia water in a third micro-reactor system to generate caprolactam, and the separated inert organic solvent is returned to an oximation reaction system for recycling.
Furthermore, in the preparation method of caprolactam, in the oximation reaction, an inert solvent, a catalyst and a raw material ketone are mixed to form a group of continuous feeding materials, hydrogen peroxide and ammonia water or liquid ammonia are respectively used as a group of continuous feeding materials, the continuously fed materials are mixed and then enter a first micro reactor or a kettle type reactor for reaction, the reaction time of the oximation reaction is 0.5 minute to 30 hours, the reaction is stopped after the feeding is finished, and then oil phase and water phase are separated through a buffer tank.
Further, in the preparation method of caprolactam, the molar ratio of oleum to cyclohexanone oxime in the rearrangement process is 0.5-2.0, SO as to obtain SO in the oleum3Free SO in oleum converted to sulfuric acid3The concentration is 2-65%, the rearrangement reaction temperature is 30-120 ℃, and the reaction time of the rearrangement reaction is 0.2-30 minutes.
Further, in the preparation method of caprolactam, in an oximation reaction, the mass percentage of cyclohexanone in raw materials is 20-80%, the molar ratio of ammonia to cyclohexanone is 0.5-10, the molar ratio of hydrogen peroxide to cyclohexanone is 1.0-5.0, and the oximation reaction temperature is 10-120 ℃.
Further, in the preparation method of caprolactam, in the oximation reaction, the oximation reaction temperature is 60-100 ℃, the molar ratio of hydrogen peroxide to cyclohexanone is 1.0-1.2, the concentration of hydrogen peroxide is 27.5-70%, and the concentration of hydrogen peroxide is preferably 40-60%.
Further, in the preparation method of caprolactam, the concentration of the catalyst in the oximation reaction is 1-10%.
Further, the preparation method of caprolactam comprises the step of carrying out oximation reaction on the caprolactam, wherein the concentration of the catalyst is 1.5-7.5%.
Further, in the preparation method of caprolactam, the molar ratio of oleum to cyclohexanone oxime in the rearrangement process is 0.8-1.3.
Further, in the preparation method of caprolactam, the reaction temperature of neutralization reaction is controlled to be 30-80 ℃, the molar ratio of caprolactam sulfonate to ammonia is 1:2, and the neutralization reaction time is 0.2-30 minutes.
Further, in the preparation method of caprolactam, in the neutralization reaction, the concentration of ammonia water is 28%, the dosage of the ammonia water is 1.6 times of the weight of fuming sulfuric acid, and the neutralization reaction time is 0.5-10 minutes.
Compared with the prior art, the invention has the beneficial effects that:
the preparation method of caprolactam of the invention, produce cyclohexanone-oxime to continue dissolving in the inert solvent of the oximation reaction in the heterogeneous catalysis oximation reaction, make cyclohexanone-oxime enter the subsequent rearrangement by way of solution rather than melting, overcome the disadvantage that cyclohexanone-oxime is apt to solidify and block the pipeline of the prior art, further reduce Beckmann rearrangement reaction initial reaction temperature at the same time, make the gradual heating control become possible, cancel the necessary alcoholic distillation process of the ammoximation process with low carbon alcohol as solvent, etc. process, the oximation reaction finishes, the oximation product does not need to prepare pure oxime through conventional separation means such as distillation, extraction, etc., do not need to add solvent to dilute, the inert solvent dissolved with product enters the microreactor of the rearrangement reaction directly, carry on Beckmann rearrangement reaction and produce caprolactam sulfonate, separate naturally with inert organic solvent at the same time, caprolactam sulfonate got carries on neutralization reaction with ammonia water in the third microreactor system to produce caprolactam, the inert organic solvent used in the oximation reaction is also a good solvent in the rearrangement reaction process, the solvent is naturally layered and separated from the product after the rearrangement reaction is finished, the solvent distillation process of the prior art is omitted, the solvent can be returned to an ammoximation reaction system for recycling, the due effect of the ammoximation reaction system is exerted again, the three reaction micro-reactor systems are used in combination, the energy consumption of the system is reduced, the reaction speed is improved, the product quality is improved, the production capacity and the efficiency are increased, the updating and the replacement of the caprolactam production technology are realized, the process is simple, and the operation is convenient;
the preparation method of caprolactam, the application of inert solvent and microreactor technology, provided by the invention, solves the problems of poor mass transfer effect caused by material viscosity rise at low temperature and low acid content, controls the reaction temperature, can further improve the reaction quality, further reduces the acid oxime ratio and byproducts, adopts a plurality of series of microreactors for combined use, realizes the technical progress of the main process of caprolactam production and the improvement of product quality, shortens the reaction time, reduces the energy consumption and improves the production safety.
Detailed Description
The following examples are intended to illustrate the invention further and should not be construed as limiting the scope of the invention.
Example 1
Mixing cyclohexanone and 1, 2-dimethyl cyclohexane solvent according to a weight ratio of 100:100, feeding an oximation catalyst TS-1 according to a weight ratio of 4%, and adding the mixture into the mixture while stirring to prepare a suspension;
introducing nitrogen into a tubular micro-reactor preheated to 80 ℃ to control the pressure of a reaction system to be about 0.35 MPa, preheating a suspension mixed by cyclohexanone and a catalyst to 60 ℃, pumping the suspension into one inlet of a pre-arranged micro-mixer of the ammoximation reaction micro-reactor by a micro-diaphragm pump at the speed of 4.0g/min, preheating ammonia water with the concentration of 25% to 60 ℃, pumping the suspension into the other inlet of the pre-arranged micro-mixer of the ammoximation reaction micro-reactor by an advection pump at the speed of 1.5g/min, continuously pumping hydrogen peroxide with the mass percentage content of 60% into a third inlet of the pre-arranged micro-mixer of the ammoximation reaction micro-reactor by the advection pump at the flow rate of 2.0ml/min, carrying out mixing reaction in the pre-arranged micro-mixer, then entering the tubular ammoximation micro-reactor controlled at the temperature of 70 ℃ for reaction for 0.5 min, preserving the temperature and collecting reaction products in an intermediate tank, keeping the temperature at 70 ℃, standing for 10 minutes to layer an oil phase and a water phase, wherein the oil phase is a light phase, the water phase is a heavy phase, the obtained oil phase is a 1, 2-dimethylcyclohexane solution containing 40% of cyclohexanone oxime, then adding the 1, 2-dimethylcyclohexane solution of the cyclohexanone oxime into a microreactor for a rearrangement reaction in batches, preferably adding the 1, 2-dimethylcyclohexane solution of the cyclohexanone oxime into the microreactor for the rearrangement reaction in three batches for better controlling the reaction temperature, wherein the first batch is the largest in addition amount, the second batch is smaller than the first batch in addition amount, the third batch is the smallest in addition amount, the ratio of the first batch in addition amount to the second batch in addition amount is 5-7:3-5, and the third batch is the rest amount, wherein the specific reaction process is as follows;
a part of the 1, 2-dimethylcyclohexane solution of the cyclohexanone oxime is injected into a pre-micro mixer of a first tubular micro reactor of the rearrangement reaction by an advection pump according to the flow rate of 2.0ml/min, all 20% fuming sulfuric acid is injected into the mixer from the other inlet of the first tubular rearrangement reaction micro reactor for mixing, and then the mixture enters the tubular rearrangement reaction micro reactor with the controlled temperature of 60 ℃ for reaction for 0.7 minute;
then pumping part of the 1, 2-dimethylcyclohexane solution of cyclohexanone oxime into a second tubular rearrangement reaction microreactor mixer connected in series for mixing by adopting an advection pump according to the flow rate of 1.5ml/min, and then entering the tubular rearrangement reaction microreactor connected in series for secondary reaction for 0.6 minute, wherein the control temperature of the tubular rearrangement reaction microreactor is 90 ℃;
thirdly, pumping part of the 1, 2-dimethylcyclohexane solution of the cyclohexanone oxime into the third microreactor mixer from the other inlet of the third microreactor mixer in series for mixing by adopting an advection pump according to the flow rate of 2.0ml/min, and then feeding the mixed solution into the tubular rearrangement reaction microreactors in series with the control temperature of 120 ℃ for carrying out a three-reaction for 0.54 minute, wherein the total acid-oxime ratio is 0.8;
collecting reaction products by heat preservation, standing for 25 minutes at 70 ℃, layering an oil phase and a water phase, separating the obtained water phase from the obtained oil phase by using an oil-water separator, mixing the oil phase and the 1, 2-dimethylcyclohexane solution again with cyclohexanone and a catalyst for ammoximation reaction, wherein the water phase is a solution containing caprolactam sulfonate, the oil phase is a 1, 2-dimethylcyclohexane solution, and the oil phase is the cyclohexanone and the catalyst;
pumping a solution containing caprolactam sulfonate into a preposed first micro mixer of a first neutralization reaction micro reactor by an advection pump according to the flow rate of 6ml/min, pumping a part of gas ammonia into an inlet of another micro reactor mixer for mixing according to 4.5g/min, then entering a first tubular neutralization reaction micro reactor with the controlled temperature of 50 ℃ for reaction for 0.6 min, then serially connecting a second preposed micro mixer, pumping another part of gas ammonia into the other inlet of the micro reactor mixer for mixing according to 4.5ml/min, then entering a second tubular neutralization reaction micro reactor with the controlled temperature of 60 ℃ for reaction for 0.55 min, collecting a reaction product in a liquid-liquid separation tank, feeding an upper layer of a crude solution of caprolactam and a lower layer of an ammonium sulfate solution into the next refining, concentrating and crystallizing treatment processes, respectively, and analyzing and calculating to obtain the caprolactam sulfonate, the conversion rate of cyclohexanone in the ammoximation reaction is 99.13 percent, and the selectivity of cyclohexanone oxime is 99.31 percent; the cyclohexanone oxime conversion rate in the rearrangement reaction is 99.99 percent; the conversion of caprolactam sulfonate was 100.00%.
Example 2
Mixing cyclohexanone and n-octane solvent according to a weight ratio of 100:200, feeding an oximation catalyst TS-1 according to a weight ratio of 3%, and adding the mixture into the mixture while stirring to prepare a suspension;
introducing nitrogen into a tubular microreactor preheated to 85 ℃ to control the pressure of a reaction system to be about 0.35-0.40MPa, preheating a suspension mixed by cyclohexanone and a catalyst to 85 ℃, pumping the suspension into one inlet of a front-arranged micromixer of the microreactor for ammoximation reaction by using a micro-diaphragm pump at the speed of 4.02g/min, preheating 25% ammonia water with the concentration to 85 ℃, pumping the ammonia water into the other inlet of the front-arranged micromixer of the microreactor for ammoximation reaction by using an advection pump at the speed of 1.47g/min, continuously pumping hydrogen peroxide with the mass percentage of 40% into the third inlet of the front-arranged micromixer of the microreactor for ammoximation reaction by using the advection pump at the flow rate of 1.8ml/min, carrying out mixing reaction in the front-arranged micromixer, then entering the tubular ammoximation microreactor at the temperature of 90 ℃ for reaction for 1.5 minutes, preserving heat and collecting reaction products in a middle tank, keeping the temperature at 60 ℃, standing for 10 minutes, and layering an oil phase and a water phase, wherein the oil phase is a light phase and the water phase is a heavy phase, the obtained oil phase is an n-octane solution containing cyclohexanone oxime, then adding the n-octane solution of cyclohexanone oxime into a microreactor for a rearrangement reaction in batches, preferably adding the n-octane solution of cyclohexanone oxime into the microreactor for the rearrangement reaction in three batches for better controlling the reaction temperature, wherein the first batch is the largest in addition amount, the second batch is smaller than the first batch in addition amount, the third batch is the smallest in addition amount, the ratio of the first batch in addition amount to the second batch in addition amount is 5-7:3-5, the third batch is the balance, and the specific reaction process is as follows;
injecting a part of n-octane solution of cyclohexanone oxime into a pre-micro mixer of a micro reactor of the rearrangement reaction by using an advection pump according to the flow rate of 2.0ml/min, injecting all 30% fuming sulfuric acid into the micro reactor mixer of the tubular rearrangement reaction from the other inlet of the micro reactor mixer of the tubular rearrangement reaction for mixing, and then reacting for 1.5 minutes in the tubular rearrangement reaction micro reactor with the controlled temperature of 60 ℃;
pumping part of the oil phase into a second tubular rearrangement reaction microreactor mixer connected in series for mixing by adopting a advection pump according to the flow rate of 1.5ml/min, and then entering a second tubular rearrangement reaction microreactor connected in series for reacting for 1.2 minutes, wherein the temperature is controlled to be 75 ℃;
thirdly, pumping part of the oil phase into the third micro-reactor mixer from the other inlet of the third micro-reactor mixer in series for mixing by adopting an advection pump according to the flow rate of 2.0ml/min, and then performing three reactions in the tubular rearrangement reaction micro-reactors in series at the control temperature of 110 ℃ for 1.1 min, wherein the total acid-oxime ratio is 1.2;
collecting a reaction product by heat preservation, standing for 15 minutes at 80 ℃, layering an oil phase and a water phase, obtaining a water phase which is a solution containing caprolactam sulfonate, separating the oil phase which is n-octane liquid from the water phase by an oil-water separator, and returning to mix with cyclohexanone and a catalyst again to carry out an ammoximation reaction;
pumping a solution containing caprolactam sulfonate into a preposed first micro mixer of a first neutralization reaction micro reactor by an advection pump according to the flow rate of 6ml/min, pumping part of gas ammonia into another micro reactor mixer according to 4.5g/min for mixing, then entering a first tubular neutralization reaction micro reactor controlled at the temperature of 35 ℃ for reaction for 0.6 min, then serially connecting a second preposed micro mixer, pumping the other part of gas ammonia into another micro reactor mixer according to 4.5ml/min for mixing, then entering a second tubular neutralization reaction micro reactor controlled at the temperature of 50 ℃ for reaction for 0.55 min, collecting a reaction product in a liquid-liquid separation tank, feeding the upper layer of the solution into a crude solution of caprolactam, feeding the lower layer of the solution into an ammonium sulfate solution, respectively carrying out the next refining, concentrating and crystallizing treatment processes, and analyzing and calculating to obtain the caprolactam sulfonate, the conversion rate of cyclohexanone in the ammoximation reaction is 99.34 percent, and the selectivity of cyclohexanone oxime is 99.54 percent; the cyclohexanone oxime conversion rate in the rearrangement reaction is 99.99 percent; the conversion of caprolactam sulfonate was 100.00%.
Example 3
Mixing cyclohexanone and n-octane solvent according to a weight ratio of 100:300, feeding an oximation catalyst TS-1 according to a weight ratio of 5%, and adding the mixture into the mixture while stirring to prepare a suspension;
introducing nitrogen into a tubular microreactor preheated to 80 ℃ to control the pressure of a reaction system to be about 0.35-0.40MPa, preheating a suspension mixed by cyclohexanone and a catalyst to 80 ℃, pumping the suspension into one inlet of a front micromixer of the microreactor for ammoximation reaction by using a micro-diaphragm pump according to the speed of 4.02g/min, preheating ammonia water with the concentration of 25% to 85 ℃, pumping the ammonia water into the other inlet of the front micromixer of the microreactor for ammoximation reaction by using an advection pump according to the speed of 1.47g/min, continuously pumping hydrogen peroxide with the mass percentage of 50% into a third inlet of the front micromixer of the microreactor for ammoximation reaction by using the advection pump at the flow rate of 1.0ml/min, carrying out mixing reaction in the front micromixer, then entering the tubular ammoximation microreactor with the control temperature of 100 ℃ for reaction for 2 minutes, preserving heat and collecting reaction products in an intermediate tank, keeping the temperature at 70 ℃, standing for 10 minutes, and layering an oil phase and a water phase, wherein the oil phase is a light phase and the water phase is a heavy phase, the obtained oil phase is an n-octane solution containing cyclohexanone oxime, then adding the n-octane solution of cyclohexanone oxime into a microreactor for a rearrangement reaction in batches, preferably adding the n-octane solution of cyclohexanone oxime into the microreactor for the rearrangement reaction in three batches for better controlling the reaction temperature, wherein the first batch is the largest in addition amount, the second batch is smaller than the first batch in addition amount, the third batch is the smallest in addition amount, the ratio of the first batch in addition amount to the second batch in addition amount is 5-7:3-5, the third batch is the balance, and the specific reaction process is as follows;
a part of the n-octane solution of cyclohexanone oxime is pumped into a pre-micro mixer of a micro reactor of the rearrangement reaction by an advection pump according to the flow rate of 2.5ml/min, all 20 percent fuming sulfuric acid is pumped into the micro reactor from the other inlet of the micro reactor mixer of the tubular rearrangement reaction for mixing, and then the micro reactor enters the tubular rearrangement reaction micro reactor with the control temperature of 60 ℃ for reaction for 1.2 minutes;
pumping part of the n-octane solution of cyclohexanone oxime into a second tubular rearrangement reaction microreactor mixer connected in series for mixing by using an advection pump according to the flow rate of 2.5ml/min, and then entering a second tubular rearrangement reaction microreactor connected in series for reacting for 1.0 minute, wherein the temperature is controlled to be 85 ℃;
thirdly, pumping part of the oil phase into the third micro-reactor mixer from the other inlet of the third micro-reactor mixer in series for mixing by adopting an advection pump according to the flow rate of 1.0ml/min, and then performing a three-reaction in the tubular rearrangement reaction micro-reactors in series with the control temperature of 100 ℃ for 0.95 min, wherein the total acid-oxime ratio is 1.6;
collecting a reaction product by heat preservation, standing for 5 minutes at the temperature of 30 ℃, layering an oil phase and a water phase, separating the obtained water phase from the water phase by using an oil-water separator to obtain a solution containing caprolactam sulfonate, separating the oil phase from the water phase by using an oil-water separator, and returning to mix with cyclohexanone and a catalyst again to carry out an ammoximation reaction;
pumping a solution containing caprolactam sulfonate into a preposed first micro mixer of a first neutralization reaction micro reactor by an advection pump according to the flow rate of 6ml/min, pumping part of gas ammonia into another micro reactor mixer according to 4.5g/min for mixing, then entering a first tubular neutralization reaction micro reactor controlled at the temperature of 40 ℃ for reaction for 0.6 min, then serially connecting a second preposed micro mixer, pumping the other part of gas ammonia into another micro reactor mixer according to the flow rate of 4.5ml/min for mixing, then entering a second tubular neutralization reaction micro reactor controlled at the temperature of 50 ℃ for reaction for 0.55 min, collecting a reaction product in a liquid-liquid separation tank, feeding the upper layer of the solution into a crude solution of caprolactam, the lower layer of the solution of ammonium sulfate into the next refining, concentrating and crystallizing treatment processes, and analyzing and calculating to obtain the caprolactam sulfonate, the conversion rate of cyclohexanone in the ammoximation reaction is 99.62 percent, and the selectivity of cyclohexanone oxime is 99.85 percent; the cyclohexanone oxime conversion rate in the rearrangement reaction is 99.99 percent; the conversion of caprolactam sulfonate was 100.00%.
Example 4
Mixing cyclohexanone and n-octane solvent according to a weight ratio of 100:500, feeding an oximation catalyst TS-1 according to a weight ratio of 5%, feeding the mixture into an external heating 250ml kettle type reactor system, and adding the mixture into the mixed solution while stirring to prepare a suspension;
introducing nitrogen into a tubular microreactor preheated to 80 ℃ to control the pressure of a reaction system to be about 0.35-0.40MPa, preheating a suspension mixed by cyclohexanone and a catalyst to 80 ℃, pumping the suspension into one inlet of a front micromixer of the microreactor for ammoximation reaction by using a micro-diaphragm pump according to the speed of 4.02g/min, preheating ammonia water with the concentration of 25% to 85 ℃, pumping the ammonia water into the other inlet of the front micromixer of the microreactor for ammoximation reaction by using an advection pump according to the speed of 1.47g/min, continuously pumping hydrogen peroxide with the mass percentage of 50% into a third inlet of the front micromixer of the microreactor for ammoximation reaction by using the advection pump at the flow rate of 1.0ml/min, carrying out mixing reaction in the front micromixer, then entering the tubular ammoximation microreactor with the control temperature of 100 ℃ for reaction for 2 minutes, preserving heat and collecting reaction products in an intermediate tank, keeping the temperature at 70 ℃, standing for 10 minutes, and layering an oil phase and a water phase, wherein the oil phase is a light phase and the water phase is a heavy phase, the obtained oil phase is an n-octane solution containing cyclohexanone oxime, then adding the n-octane solution of cyclohexanone oxime into a microreactor for a rearrangement reaction in batches, preferably adding the n-octane solution of cyclohexanone oxime into the microreactor for the rearrangement reaction in three batches for better controlling the reaction temperature, wherein the first batch has the largest addition amount, the second batch has the smaller addition amount than the first batch, the third batch has the smallest addition amount, the ratio of the first addition amount to the second addition amount is 5-7:3-5, the third batch has the balance, and the specific reaction process is as follows;
a part of the n-octane solution of cyclohexanone oxime is pumped into a pre-micro mixer of a micro reactor of the rearrangement reaction by an advection pump according to the flow rate of 2.5ml/min, all 20 percent fuming sulfuric acid is pumped into the micro reactor from the other inlet of the micro reactor mixer of the tubular rearrangement reaction for mixing, and then the micro reactor enters the tubular rearrangement reaction micro reactor with the control temperature of 65 ℃ for reaction for 1.2 minutes;
pumping part of the n-octane solution of cyclohexanone oxime into a second tubular rearrangement reaction microreactor mixer connected in series for mixing by using an advection pump according to the flow rate of 3.5ml/min, and then entering a second tubular rearrangement reaction microreactor connected in series for reacting for 0.9 minute, wherein the temperature is controlled to be 85 ℃;
thirdly, pumping part of the oil phase into the third micro-reactor mixer from the other inlet of the third micro-reactor mixer in series for mixing by adopting an advection pump according to the flow speed of 0.5ml/min, and then performing three reactions in the tubular rearrangement reaction micro-reactors in series at the control temperature of 95 ℃ for 0.95 min, wherein the total acid-oxime ratio is 1.1;
collecting a reaction product by heat preservation, standing for 5 minutes at the temperature of 30 ℃, layering an oil phase and a water phase, separating the obtained water phase from the water phase by using an oil-water separator to obtain a solution containing caprolactam sulfonate, separating the oil phase from the water phase by using an oil-water separator, and returning to mix with cyclohexanone and a catalyst again to carry out an ammoximation reaction;
pumping a solution containing caprolactam sulfonate into a preposed first micro mixer of a first neutralization reaction micro reactor by an advection pump according to the flow rate of 6ml/min, pumping part of gas ammonia into another micro reactor mixer according to 4.5g/min for mixing, then entering a first tubular neutralization reaction micro reactor controlled at the temperature of 30 ℃ for reaction for 0.4 min, then serially connecting a second preposed micro mixer, pumping the other part of gas ammonia into another micro reactor mixer according to 4.5ml/min for mixing, then entering a second tubular neutralization reaction micro reactor controlled at the temperature of 50 ℃ for reaction for 2.65 min, collecting a reaction product in a liquid-liquid separation tank, feeding the upper layer of the solution into a crude solution of caprolactam, feeding the lower layer of the solution into the ammonium sulfate solution, respectively carrying out the next refining, concentrating and crystallizing treatment processes, and analyzing and calculating to obtain the caprolactam sulfonate, the conversion rate of cyclohexanone in the ammoximation reaction is 99.62 percent, and the selectivity of cyclohexanone oxime is 99.85 percent; the cyclohexanone oxime conversion rate in the rearrangement reaction is 99.99 percent; the conversion of caprolactam sulfonate was 100.00%.
In the invention, the full series of the ammoximation reaction, the cyclohexanone oxime rearrangement reaction and the neutralization reaction respectively adopt a microreactor system, thus shortening the reaction time, reducing by-products, improving the heat transfer and mass transfer capacities, stably controlling the reaction temperature and improving the product quality; the method has the advantages of simple process, higher operation safety and selectivity, mild conditions, high-efficiency reaction at room temperature, short reaction time, capability of enabling the conversion rate of the cyclohexanone-oxime to reach 100% and the selectivity of the caprolactam to reach more than 99% in a shorter time, great reduction of energy consumption and reduction of production cost on the premise of maintaining higher yield, environmental protection and high efficiency, and has industrial application prospect.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. 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. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The preparation method of caprolactam is characterized by comprising the following steps: under the condition of existence of an inert solvent, heterogeneous catalytic oximation reaction is carried out on cyclohexanone, hydrogen peroxide, a catalyst and ammonia in a first micro-reactor system or a kettle type reactor to generate cyclohexanone oxime, the obtained cyclohexanone oxime solution is subjected to Beckmann rearrangement reaction in a second micro-reactor system under the action of fuming sulfuric acid to generate caprolactam sulfonate, a reaction product and an inert organic solvent are naturally separated to obtain a caprolactam sulfonate water phase, the caprolactam sulfonate water phase is subjected to neutralization reaction with ammonia water in a third micro-reactor system to generate caprolactam, and the separated inert organic solvent is returned to an oximation reaction system for recycling.
2. The process for producing caprolactam according to claim 1, wherein in the oximation reaction, an inert solvent, a catalyst and a raw material ketone are mixed as a set of continuous feeds, hydrogen peroxide and ammonia water or liquid ammonia are respectively continuously fed as a set of feeds, and the feeds are mixed and then fed into a first microreactor or a tank reactor to be reacted, wherein the reaction time of the oximation reaction is 0.5 minutes to 30 hours, the reaction is terminated after the feeding, and then the separation of the oil phase from the water phase is carried out by a buffer tank.
3. The process for producing caprolactam according to claim 2, wherein the molar ratio of oleum to cyclohexanone oxime in the rearrangement process is 0.5 to 2.0, based on SO in oleum3Free SO in oleum converted to sulfuric acid3The concentration is 2-65%, the rearrangement reaction temperature is 30-120 ℃, and the reaction time of the rearrangement reaction is 0.2-30 minutes.
4. The method for preparing caprolactam according to claim 3, wherein in the oximation reaction, the mass percentage of cyclohexanone in the raw material is 20-80%, the molar ratio of ammonia to cyclohexanone is 0.5-10, the molar ratio of hydrogen peroxide to cyclohexanone is 1.0-5.0, and the oximation reaction temperature is 10-120 ℃.
5. The process for producing caprolactam according to claim 3, wherein the temperature of the oximation reaction in the oximation reaction is 60 to 100 ℃ and the molar ratio of hydrogen peroxide to cyclohexanone is 1.0 to 1.2.
6. A process for producing caprolactam according to claim 3, wherein the catalyst concentration in the oximation reaction is 1 to 10%.
7. Process for the preparation of caprolactam according to claim 3, wherein the catalyst concentration in the oximation reaction is 1.5 to 7.5%.
8. The process for producing caprolactam according to claim 3, wherein the molar ratio of oleum to cyclohexanone oxime in the rearrangement is 0.8 to 1.3.
9. The process for producing caprolactam according to claim 3, wherein the reaction temperature of the neutralization reaction is controlled to 30 to 80 ℃, the molar ratio of caprolactam sulfonate to ammonia is 1:2, and the neutralization reaction time is 0.2 to 30 minutes.
10. The process for producing caprolactam according to claim 3, wherein the neutralization reaction is carried out in the presence of 28% by weight of aqueous ammonia based on 1.6 times the weight of oleum and for a time period of 0.5 to 10 minutes.
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