[go: up one dir, main page]

CN113941303A - Nitration system, synthesis system and method for continuously synthesizing permanent violet - Google Patents

Nitration system, synthesis system and method for continuously synthesizing permanent violet Download PDF

Info

Publication number
CN113941303A
CN113941303A CN202111287112.6A CN202111287112A CN113941303A CN 113941303 A CN113941303 A CN 113941303A CN 202111287112 A CN202111287112 A CN 202111287112A CN 113941303 A CN113941303 A CN 113941303A
Authority
CN
China
Prior art keywords
nitration
kettle
reaction
ethyl carbazole
microreactor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202111287112.6A
Other languages
Chinese (zh)
Other versions
CN113941303B (en
Inventor
汪国建
殷守华
孙涛
陶文大
胡平
刘邦坤
宁亮
王彬彬
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anhui Shenlanhua Color Material Co ltd
Original Assignee
Anhui Shenlanhua Color Material Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anhui Shenlanhua Color Material Co ltd filed Critical Anhui Shenlanhua Color Material Co ltd
Priority to CN202111287112.6A priority Critical patent/CN113941303B/en
Publication of CN113941303A publication Critical patent/CN113941303A/en
Priority to JP2022083748A priority patent/JP7570752B2/en
Application granted granted Critical
Publication of CN113941303B publication Critical patent/CN113941303B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0093Microreactors, e.g. miniaturised or microfabricated reactors
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07DHETEROCYCLIC COMPOUNDS
    • C07D498/00Heterocyclic compounds containing in the condensed system at least one hetero ring having nitrogen and oxygen atoms as the only ring hetero atoms
    • C07D498/22Heterocyclic compounds containing in the condensed system at least one hetero ring having nitrogen and oxygen atoms as the only ring hetero atoms in which the condensed system contains four or more hetero rings
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09BORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B19/00Oxazine dyes
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00Technologies relating to chemical industry
    • Y02P20/10Process efficiency

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Indole Compounds (AREA)
  • Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)

Abstract

The invention relates to a nitration system, a synthesis system and a method for continuously synthesizing permanent violet, wherein the nitration system comprises an ethyl carbazole dissolving kettle, a micro-reactor and a reaction liquid receiving tank which are sequentially connected, the ethyl carbazole dissolving kettle is provided with an ethyl carbazole feeding port and an o-dichlorobenzene feeding port, the micro-reactor is provided with a nitric acid feeding port, and a discharge port of the reaction liquid receiving tank is used for outputting a nitration product containing 3-nitro-N-ethyl carbazole; the synthetic system comprises a nitration system and a hydrogenation reduction system, wherein the hydrogenation reduction system comprises a reduction dehydration kettle, a hydrogenation reduction kettle, a dehydration kettle condensation reaction kettle and a closed-loop reaction kettle which are sequentially connected, and a material inlet of the reduction dehydration kettle is communicated with a material outlet of an oil phase of a water diversion tank. The nitration system and the synthesis system can improve the intrinsic safety of nitration reaction, improve the conversion rate of raw materials and effectively improve the yield of products.

Description

Nitration system, synthesis system and method for continuously synthesizing permanent violet
Technical Field
The invention relates to the technical field of organic pigment preparation, mainly relates to the technical field of permanent violet preparation, and particularly relates to a nitration system, a synthesis system and a method for continuously synthesizing permanent violet.
Background
Permanent violet RL with the dye index number C.I. pigment violet 23, the structural formula of which is as follows:
Figure BDA0003333515930000011
the permanent violet RL is one of the more expensive pigments in the world today and it is also the best violet pigment used in the plastics industry today. Among the existing violet pigment varieties, c.i. pigment violet 23 has the best tinctorial strength, while also having outstanding lightness, excellent heat resistance, bleed resistance and good light fastness. The dye can be matched with phthalocyanine blue pigment, and the good light fastness can be still maintained after the color tone is adjusted. Even its light-colored articles exhibit satisfactory weather fastness. C.i. pigment violet when used in minute amounts can make white coatings and plastic products appear whiter, actually playing a whitening role.
The synthesis of the permanent violet crude product takes carbazole as a starting raw material, the carbazole reacts with bromoethane in the presence of a phase transfer catalyst to obtain ethyl carbazole, the ethyl carbazole is nitrified in chlorobenzene by dilute nitric acid to obtain 3-nitro-N-ethyl carbazole, the 3-amino-N-ethyl carbazole is obtained through hydrogenation reduction, and the condensation and ring-closure reaction of the 3-nitro-N-ethyl carbazole and tetrachlorobenzoquinone are carried out to obtain the permanent violet RL crude product. Wherein the yield of the N-ethylation reaction is up to more than 96%, the yield of the nitration reaction is less than 70%, the yield of the reduction reaction is up to more than 95%, and the yield of the condensation and ring-closure reaction is more than 92%.
Because the nitration of the N-ethyl carbazole belongs to heterogeneous reaction, and simultaneously, solids are separated out in the reaction process, the nitration process of the domestic permanent violet production enterprise adopts a kettle type reactor intermittent operation process for production, and the production process mainly comprises the following stages: (1) nitration: and (3) discharging the ethyl carbazole chlorobenzene solution to a nitration kettle, stirring and cooling, slowly dropwise adding a nitric acid solution, and controlling the reaction temperature within a certain range. And (3) continuing heat preservation after the dropwise addition of the nitric acid is finished, sampling and detecting, cooling to below 10 ℃ after the reaction is finished when the content of the raw material ethyl carbazole is less than 0.5%, and slowly dropwise adding the liquid caustic soda to adjust the pH value of the system to be neutral. Centrifugally filtering, washing, centrifugally dewatering, discharging and bagging to obtain the nitro-compound 3-nitro-N-ethyl carbazole for later use. And (4) the mother liquor enters a chlorobenzene solvent recovery system to recover chlorobenzene. (2) Hydrogenation reduction: and (2) putting the nitro compound 3-nitro-N-ethyl carbazole into an o-dichlorobenzene solvent, heating to dehydrate, and after dehydration, feeding into a hydrogenation reduction kettle for hydrogenation reduction. And after the hydrogenation reduction is finished, the materials enter the condensation and closed-loop processes to finally obtain the permanent violet crude product. Wherein, the nitration reaction belongs to a strong exothermic reaction, the nitration reaction is carried out in a conventional kettle type reactor, the phenomenon of local overheating often occurs because the mixing rate and the heat exchange efficiency are not high, the local overheating often causes by-product generation, and the yield and the selectivity are reduced. Meanwhile, if a large amount of heat generated by violent reaction cannot be timely led out, the material flushing and even explosion accidents can be caused. In addition, in the conventional kettle type reaction, the reactant is usually added dropwise gradually to prevent the reaction from being too violent, so that a part of the reactant added firstly has too long retention time. For many reactions, a long residence time of reactants, products or intermediate transition products under the reaction conditions results in the production of a large number of by-products, the chemical equation of which is shown below:
Figure BDA0003333515930000021
disclosure of Invention
The inventor believes that the existing synthesis process of the permanent violet pigment has the following defects: (1) the nitration reaction releases heat violently, and the kettle type reaction has a large thermal runaway risk and a large safety risk; (2) the kettle type reaction has poor stirring effect, and the phenomenon of local overheating exists when the nitric acid is dripped, so that the nitration selectivity is poor, and reaction byproducts are more; (3) the kettle type reaction efficiency is low, the dosage of nitric acid is large, and the mole number exceeds 2 times of that of ethyl carbazole. In order to reduce the risk of thermal runaway, the dripping speed and the reaction temperature of nitric acid are often controlled, so that the reaction time is longer and the reaction efficiency is lower; (4) the long-time retention of the materials in the kettle will result in the increase of the content of the by-products; (5) the target product of the nitration reaction is 3-nitro-N-ethyl carbazole, under the existing kettle type reaction condition, the main content of the nitration reaction is about 80%, the content of isomer by-products is more than 12%, the content of polynitro compounds, particularly dinitrate by-products is more than 2.5%, and the higher the polynitro content is, the higher the explosion risk of the system is, and the generation of polynitro needs to be strictly controlled; (6) the reaction continuity is poor, solid-liquid separation is needed firstly after the nitration reaction is finished, and a nitro compound is needed to be dissolved in o-dichlorobenzene before hydrogenation reduction is carried out, so that the reaction efficiency is obviously reduced. On the other hand, in the solid-liquid separation process, a part of nitro-compounds is dissolved in the solvent and enters the mother liquor, resulting in material loss and yield reduction.
The technical problem solved by the invention is as follows: the conventional synthesis process of permanent violet has the risk of thermal runaway, large raw material consumption, long reaction time, excessive byproducts, poor reaction continuity, low reaction efficiency and product yield and quality to be improved.
The purpose of the invention is: the excellent mass transfer and heat transfer effects of the microreactor are utilized, the safety of the permanent violet synthesis process is improved, parameters such as reaction temperature, time and the like are effectively controlled, the reaction conversion rate is improved, the synthesis process is continuous, and the product yield is improved.
Particularly, aiming at the defects of the prior art, the invention adds a microreactor into a permanent violet synthesis process system, wherein the microreactor has extremely large specific surface area, which determines that the microreactor has extremely large heat exchange efficiency, and even if a large amount of heat is instantaneously released in the reaction, the microreactor can absorb the heat in time to maintain the reaction temperature not to exceed a set value. On one hand, the method can effectively avoid the influence of the reaction yield and selectivity caused by the generation of by-products due to local overheating; on the other hand, even if the reaction system is out of control, the damage degree is very effective because the liquid holdup of the system is less, thereby greatly improving the intrinsic safety of the reaction system. Meanwhile, the micro-reactor technology adopts continuous flow reaction in the micro-channel, can accurately control the residence time of materials under reaction conditions, immediately transmits the materials to the next reaction or stops the reaction once the optimal reaction time is reached, and can effectively eliminate the generation of by-products caused by long reaction time.
The nitration system for continuously synthesizing the permanent violet is characterized by comprising an ethyl carbazole dissolving kettle, a microreactor and a reaction liquid receiving tank which are sequentially connected, wherein the ethyl carbazole dissolving kettle is provided with an ethyl carbazole feeding port and an o-dichlorobenzene feeding port, the microreactor is provided with a nitric acid feeding port, and a discharge port of the reaction liquid receiving tank is used for outputting a nitration product containing 3-nitro-N-ethyl carbazole;
the micro-reactor comprises a shell and an inner cylinder arranged inside the shell, a micro-reaction channel is arranged between the inner cylinder and the shell, the micro-reaction channel penetrates through the shell to form a micro-reactor feeding port and a discharging port, and at least one of the inner cylinder and the shell is connected with a driving device.
Preferably, in the above-mentioned nitration system, the diameter of the micro reaction channel is less than 10mm, preferably 5-8mm, and the length is 1000-1500mm, preferably 1300-1500 mm.
Preferably, in the above-mentioned nitration system, the relative rotation speed of the outer shell and the inner column of the microreactor is 900-.
Preferably, in the above nitration system, the specific surface area of the micro reaction channel can reach 10000-2/m3
Preferably, in the nitration system, the reaction liquid receiving tank inlet includes a pH adjuster inlet.
Preferably, in the nitration system, a discharge port of the reaction liquid receiving kettle is connected with a water diversion tank, a discharge port of the water diversion tank is provided with a water phase discharge port and an oil phase discharge port, and the oil phase discharge port is used for outputting a nitration product containing 3-nitro-N-ethyl carbazole.
Preferably, in the nitration system, an ortho-dichlorobenzene feeding port of the dissolution kettle is connected with an ortho-dichlorobenzene metering tank, and a discharge port of the dissolution kettle is connected with an ethyl carbazole solution turnover tank; the nitric acid feeding port is connected with a dilute nitric acid turnover tank; and a feed inlet of the reaction liquid receiving kettle is connected with an alkali liquor metering tank.
The invention also provides a synthesis system for continuously synthesizing permanent violet, which is characterized by comprising the nitration system and the hydrogenation reduction system, wherein the hydrogenation reduction system comprises a reduction dehydration kettle, a hydrogenation reduction kettle, a dehydration kettle, a condensation reaction kettle and a closed-loop reaction kettle which are sequentially connected.
Preferably, in the above synthesis system, the feed port of the reduction dehydration kettle is communicated with the oil phase discharge port of the water diversion tank.
Preferably, in the synthesis system, the discharge port of the condensation closed-loop reaction kettle is further connected with a centrifuge.
The invention also provides a nitration method for continuously synthesizing permanent violet, which is characterized in that the nitration system is started, ethyl carbazole and o-dichlorobenzene are added into an ethyl carbazole dissolving kettle and mixed to form a mixed solution of ethyl carbazole and o-dichlorobenzene, the mixed solution is introduced into a microreactor, dilute nitric acid is added into the microreactor, and after the reaction is finished, the obtained reaction solution is introduced into a reaction solution receiving tank to be cooled, so that a nitration product containing 3-nitro-N-ethyl carbazole is obtained.
Preferably, in the above nitration method, a pH regulator is added to the reaction liquid receiving tank to adjust the pH value to 6.5 to 7.5.
Preferably, in the above nitration system, the molar ratio of ethyl carbazole to nitric acid at the inlet of the microreactor is 1.00: (1.01 to 3.00), preferably 1.00: (1.01-2.00).
Preferably, in the above nitration system, the reaction temperature in the microreactor is from 30 to 100 ℃, preferably from 40 to 95 ℃.
Preferably, in the nitration system, the concentration of the ethyl carbazole in the ethyl carbazole dissolving kettle is 1.0-5.0 kmol/L; the concentration of the nitric acid is 1.0-10.0 kmol/L.
Preferably, in the nitration method, the reaction time in the microreactor is 5-10min, and the temperature of the material in the reaction liquid receiving tank is reduced to 0-10 ℃.
Preferably, in the nitration method, the discharge port of the reaction liquid receiving kettle is connected with a water diversion tank, the discharge port of the water diversion tank is provided with a water phase discharge port and an oil phase discharge port, and the oil phase discharge port obtains a nitration product containing 3-nitro-N-ethyl carbazole;
introducing a product obtained from a discharge port of the reaction liquid receiving kettle into a water diversion tank for water diversion, introducing an obtained water phase material into a wastewater treatment system, and obtaining an oil phase material containing a nitration product of 3-nitro-N-ethyl carbazole.
Preferably, in the nitration method, an ortho-dichlorobenzene feeding port of the dissolution kettle is connected with an ortho-dichlorobenzene metering tank, and a discharge port of the dissolution kettle is connected with an ethyl carbazole solution turnover tank; the nitric acid feeding port is connected with a dilute nitric acid turnover tank; a feed inlet of the reaction liquid receiving kettle is connected with an alkali liquor metering tank;
and (3) introducing the o-dichlorobenzene into the dissolving kettle through the metering tank, introducing the o-dichlorobenzene into the ethyl carbazole solution turnover tank after dissolving, introducing the o-dichlorobenzene into the microreactor, and introducing the nitric acid solution into the microreactor through the acid preparation kettle and the dilute nitric acid turnover tank.
Preferably, in the nitration method, the nitration reaction yield is 80-90%. The content of the main product of the nitration reaction, namely the content of 3-nitro-ethyl carbazole in the nitration product is 80-95%, preferably 90-95%. The isomeric extract by-product content is < 10%, preferably < 5%, polynitro by-product < 3.5%, preferably < 1%, more preferably < 0.25%, more preferably < 0.15%.
The invention also provides a synthetic method for continuously synthesizing permanent violet, which is characterized by comprising the nitration method and the following steps: and starting the synthesis system, introducing the material containing 3-nitro-N-ethyl carbazole into a reduction dehydration kettle, removing water through reduced pressure distillation, introducing the obtained material into a hydrogenation reduction kettle for hydrogenation reduction, introducing the dehydrated material into a condensation reaction kettle, performing condensation reaction with tetrahydrobenzoquinone, introducing the product into a closed-loop reaction kettle, adding benzenesulfonyl chloride, and cutting off the previous fraction to obtain the permanent violet pigment.
Preferably, the hydrogenation reaction process is as follows: conveying the material dehydrated by the reduction dehydration kettle to a reduction kettle by a pump, adding flaky Raney nickel and ammonia water under the stirring condition, introducing nitrogen to replace the air in the reduction kettle, detecting that the oxygen content in the reduction kettle meets the safety requirement, closing a nitrogen inlet valve, heating, opening a hydrogen inlet valve, introducing hydrogen, and carrying out hydrogenation reduction.
Preferably, after the reduction is finished, the temperature is reduced, the kettle is slowly emptied until the pressure in the kettle is zero, and then nitrogen is introduced for replacement twice. Filtering the material, recovering the catalyst, and feeding the material liquid into the next working procedure.
Preferably, the concentration of the ammonia water is 15-20%, and the mass ratio of the dehydrated material to the raney nickel is (370-: 1. the mass ratio of the dehydrated material to the ammonia water is (60-95): 1. the hydrogen flow rate is 2-5 m3H is used as the reference value. The temperature of the hydrogenation reduction reaction is 120-130 ℃, and the reaction time is 8-10 hours.
Preferably, the dehydration process after hydrogenation reduction is as follows: the reaction material is from the reducing substance in a hydrogenation kettle (hydrogenation reduction kettle), o-dichlorobenzene is added into a dehydration kettle, the reducing substance in a homogenizing kettle is transferred to the dehydration kettle by vacuum, steam is used for raising the temperature and distilling to 130 ℃ through a jacket, a vacuum valve of a receiving tank is slowly opened for negative pressure distillation to 140 ℃, and the temperature is reduced to 70-80 ℃.
Preferably, the weight ratio of the reducing substance in the hydrogenation reduction kettle to the o-dichlorobenzene is (125- & ltSUB- & gt 150-): (650-750).
Preferably, the condensation reaction process is as follows: transferring the material obtained from the dehydration kettle into a condensation reaction kettle in vacuum, adding tetrachlorobenzoquinone, dropwise adding an acid binding agent, and preserving heat for 5-10 hours at the temperature of 40 +/-1 ℃ to obtain a condensation compound.
Preferably, the acid-binding agent is triethylamine, and the weight ratio of the reducing substance in the hydrogenation reduction kettle to the tetrachlorobenzoquinone is (125-150): (65-95), wherein the weight ratio of the chloranil to the acid-binding agent is (65-95): (85-105).
Preferably, the closed loop process is: and (3) putting a condensation compound of a reaction material from a condensation kettle into a corresponding closed loop kettle, heating by jacket heat conduction oil, adding benzenesulfonyl chloride to cut off front fraction, continuously heating to 175 ℃, preserving heat, refluxing for 5 hours, cooling to 130 ℃, centrifugally discharging and washing to obtain the permanent violet.
Preferably, the weight ratio of the reducing substance in the hydrogenation reduction kettle to the benzene sulfonyl chloride is (125- & 150): (18-35). The outer surface of an inner cylinder of the microreactor is attached to the inner surface of an outer shell, and a tubular gap is arranged around the outer wall of the inner cylinder at the attached position to form a micro-reaction channel; the outer shell or the inner column is connected with a driving device, or both the outer shell and the inner column are connected with the driving device, so that the outer shell or the inner column rotates around an axis; the outer shell can be fixed, and the inner cylinder can rotate; or the inner cylinder is fixed and the outer shell rotates; or the two rotate in opposite directions, and the materials in the micro-channel are mixed by means of the relative rotation of the two. The relative rotational speed of the outer housing and the inner cylinder is the difference between the rotational speeds of the two.
The invention has the advantages that: (1) the intrinsic safety is obviously improved, the micro-reactor has excellent mass and heat transfer effects, so that the heat accumulation can be effectively avoided, and meanwhile, due to the continuity, the liquid holdup in the reactor is small, so that the intrinsic safety of the nitration reaction is greatly improved; (2) because key parameters such as reaction temperature, time, raw material proportion and the like can be accurately controlled, the selectivity of the reaction is greatly improved, and the generation of byproducts is reduced, thereby improving the conversion rate of the raw materials; (3) because the solid-liquid separation link of the nitrated compound is cancelled, the material loss is reduced, and the product yield is effectively improved.
Drawings
FIG. 1 is a schematic diagram of the nitrification system described in example 1-1.
FIG. 2 is a schematic diagram of the nitrification system described in examples 1-2.
FIG. 3 is a schematic diagram of the nitration system described in examples 1-3.
Fig. 4 is a schematic diagram of the permanent violet synthesis system described in example 2-2.
FIG. 5 is a liquid chromatography spectrum of the nitration reaction product described in example 3-1.
FIG. 6 is a schematic diagram of a nitration system as described in the comparative example.
Fig. 7 is a schematic diagram of a permanent violet synthesis system as described in the comparative example.
Detailed Description
In order to solve the problems of thermal runaway risk, long reaction time, low reaction efficiency and incapability of continuous production in the conventional permanent violet synthesis process, the invention adopts a synthesis system containing a micro-reactor, so that the permanent violet can be continuously produced, and the product quality and yield are improved.
In a preferred embodiment, the method for continuously synthesizing permanent violet comprises the following steps: (1) preparing an ethyl carbazole o-dichlorobenzene solution: dissolving a certain amount of ethyl carbazole in a proper amount of o-dichlorobenzene to prepare an ethyl carbazole o-dichlorobenzene solution with the molar concentration of 1.0-5.0kmol/L for later use. (2) Preparing a dilute nitric acid solution: dissolving a certain amount of concentrated nitric acid in a proper amount of water to prepare a nitric acid solution with the molar concentration of 1.0-10.0kmol/L for later use. (3) Nitration reaction: starting the microreactor, and using a metering pump which is accurately metered through verification to obtain n-ethyl carbazole: n-nitric acid 1.00: (1.01-2.00) continuously pumping the ethyl carbazole/o-dichlorobenzene solution and the dilute nitric acid solution into the microreactor respectively, fully mixing and carrying out efficient mass and heat transfer, strictly controlling parameters such as reaction temperature, reaction time, mixing effect and the like, so that the two raw materials fully react in the microreactor, continuously feeding the reaction liquid into a receiving tank from the reactor, stirring, cooling and adjusting the pH value of the reaction liquid in the receiving tank, and completely stopping nitration reaction. (4) And the material in the receiving tank enters a water diversion tank for diversion, the water phase enters a wastewater treatment system, the oil phase enters a reduction dehydration kettle for reduced pressure distillation to remove residual water, the dehydrated material enters a hydrogenation reduction kettle for hydrogenation reduction, and the material enters the next procedures of condensation, closed loop and the like after reduction, so that the permanent violet crude product is finally obtained. Preferably, the concentration range of the dilute nitric acid is 1.0-10.0 kmol/L; the reaction temperature is 40-95 ℃.
The continuous production permanent violet system of the invention has the following characteristics:
(1) the micro reactor in the system can effectively improve the reaction interface, promote the reaction mass transfer, and can obtain the solid with uniform particle size distribution when used for the reaction with the solid. The device is suitable for gas-liquid two-phase reaction, can effectively improve the interface, effectively control bubble coalescence, promote the interaction stroke of bubbles and a liquid phase, and is beneficial to single-pass absorption of the liquid phase. (2) The aim of improving the selectivity of the nitration reaction is achieved by controlling the reaction temperature, the reaction time and the mixing effect, so that the main nitration content exceeds 90%, the content of isomer by-products is less than 5%, and the content of polynitro by-products is less than 0.25%, and finally the aim of improving the reaction conversion rate is achieved.
(3) And (5) optimizing the process. In the nitration stage, o-dichlorobenzene is used for replacing chlorobenzene to dissolve ethyl carbazole, standing and layering are carried out after the reaction is finished, a lower-layer solvent phase enters a dehydration kettle to be dehydrated and then enters a reduction kettle, an upper-layer water phase enters a sewage treatment system, so that the synthesis process is continuous, loss caused by dissolving nitro-compounds in the solvent is avoided by canceling a centrifugation link, and the product yield is greatly improved.
The invention realizes the application of the micro-reactor technology in the permanent violet synthesis process, and improves the intrinsic safety, the reaction selectivity and the conversion rate of the system by utilizing the micro-reactor; o-dichlorobenzene is used for replacing chlorobenzene, a centrifugal solid-liquid separation link is omitted, the process continuity is improved, the material loss is reduced, and the product yield is improved; only one solvent is in the system, which is beneficial to the recovery of the solvent, avoids cross influence and reduces the consumption of the solvent;
the system and method for continuous synthesis of permanent violet according to the present invention are further illustrated by the following specific examples.
The sources of the chemical reagents used in the present invention are: o-dichlorobenzene: the purity of Jiangsu Longchang chemical industry limited company is more than or equal to 99.0 percent, and the content of nitric acid: the purity of Ningxia Runja energy chemical industry limited company is more than or equal to 98 percent.
The device information used in the present invention is:
liquid chromatography: the manufacturer: shimadzu, Japan, model: LC-20A.
EXAMPLE 1 nitration System for the continuous Synthesis of permanent Violet
Examples 1 to 1
The schematic diagram of the nitration system is shown in fig. 1, and the nitration system comprises an ethyl carbazole dissolving kettle, a microreactor and a reaction liquid receiving tank which are connected in sequence, wherein a material inlet of the ethyl carbazole dissolving kettle comprises an ethyl carbazole material inlet and an o-dichlorobenzene material inlet, a microreactor material inlet comprises a nitric acid material inlet and an ethyl carbazole o-dichlorobenzene solution material inlet, a reaction liquid receiving tank material inlet comprises a pH regulator material inlet, and a reaction liquid receiving tank material outlet obtains 3-nitro-N-ethyl carbazole, wherein the microreactor is made of a corrosion-resistant material, and the microreactor is made of hastelloy.
The structure of the microreactor comprises a shell and an inner cylinder arranged inside the shell, a micro-reaction gap is formed between the inner cylinder and the shell, the diameter of the gap is smaller than 10mm, and the inner cylinder and the shell are connected with a driving device and can rotate around an axis. When adding the material in little reaction gap, through the relative motion of shell body and interior cylinder, make the material carry out mass transfer diffusion, the homogeneous mixing forms the fluid film, makes the reaction process more high-efficient, stable, in addition, is provided with the hot plate at shell body internal surface and/or interior cylinder surface for the heating material. Preferably, the inner wall of the outer shell and the outer wall of the inner cylinder are coated with an anticorrosive material.
The operation process of the nitration system is as follows: adding ethyl carbazole and o-dichlorobenzene into an ethyl carbazole dissolving kettle, mixing to form an ethyl carbazole o-dichlorobenzene solution, introducing the ethyl carbazole o-dichlorobenzene solution into a microreactor, adding dilute nitric acid into the microreactor, starting the microreactor, controlling the proportion of the ethyl carbazole o-dichlorobenzene solution and the dilute nitric acid to fully mix and react in the microreactor, introducing the obtained reaction liquid into a reaction liquid receiving tank, stirring and cooling, adding a pH regulator, adjusting the pH value of the reaction liquid, and completely terminating the nitration reaction to obtain a nitration product containing 3-nitro-N-ethyl carbazole.
Wherein, in the ethyl carbazole o-dichlorobenzene solution, the concentration of ethyl carbazole is 1.0-5.0 kmol/L; the concentration of the dilute nitric acid is 1.0-10.0 kmol/L; in the microreactor, the molar ratio of ethyl carbazole to nitric acid in raw materials is 1.00: (1.01-2.00), the relative rotation speed of the inner cylinder and the outer shell of the micro-reactor is 1000-. The reaction temperature in the micro reactor is 40-95 ℃, the reaction time is 5-10min, the temperature of the materials in the reaction liquid receiving tank is reduced to 0-10 ℃, and the pH is regulated to 6.5-7.5.
Examples 1 to 2
The nitration system of this example is similar to example 1-1, and the schematic diagram is shown in FIG. 2, and the differences from example 1-1 are: an o-dichlorobenzene feeding port of the ethyl carbazole dissolving kettle is connected with an o-dichlorobenzene metering tank for accurately metering the addition amount of o-dichlorobenzene, and a discharging port of the ethyl carbazole dissolving kettle is connected with an ethyl carbazole solution storage tank; a feeding port of the micro-reactor is connected with an alkylated carbazole liquid storage tank (ethyl carbazole liquid storage tank) and a dilute nitric acid liquid storage tank, and the feeding port of the dilute nitric acid liquid storage tank is connected with an acid preparation kettle for preparing dilute nitric acid with required concentration; and a pH regulator feeding port of the reaction liquid receiving kettle is connected with a liquid caustic soda metering tank for regulating the addition amount of liquid caustic soda.
Examples 1 to 3
The nitration system of this example is similar to that of example 1-2, and is schematically shown in FIG. 3, and differs from example 1-2 in that: the discharge hole of the reaction liquid receiving kettle is connected with a water diversion tank, the discharge hole of the water diversion tank comprises a water phase discharge hole and an oil phase discharge hole, the water phase discharge hole is connected with a wastewater treatment system, and the oil phase discharge hole obtains a nitration product containing 3-nitro-N-ethyl carbazole.
During operation, a product obtained from a discharge port of the reaction liquid receiving kettle is introduced into a water diversion tank for water diversion, an obtained water phase material enters a wastewater treatment system, and an obtained oil phase material contains a nitration product of 3-nitro-N-ethyl carbazole.
Preferably, the oil phase discharge port is connected with a dehydration kettle, and the water in the oil phase is further removed through reduced pressure distillation.
EXAMPLE 2 permanent violet Synthesis System
Example 2-1
The permanent violet synthesis system comprises the nitration system and the hydrogenation reduction system in embodiments 1-3, wherein the hydrogenation reduction system comprises a reduction dehydration kettle, a hydrogenation reduction kettle, a dehydration kettle, a condensation reaction kettle and a closed-loop reaction kettle which are sequentially connected, and a material inlet of the reduction dehydration kettle is communicated with a material outlet of an oil phase of a water diversion tank. In the reaction liquid receiving tank, the nitration reaction is terminated, and the water diversion tank is arranged, so that the service efficiency of the reaction liquid receiving kettle can be improved, most of water can be directly separated by utilizing the compatibility and density difference of materials and water, and the improvement of the dehydration efficiency and the energy consumption saving are facilitated.
During operation, oil phase materials of the water diversion tank are introduced into a reduction dehydration kettle, water is removed after reduced pressure distillation, the obtained materials are introduced into a hydrogenation reduction kettle for hydrogenation reduction, water is removed through reduced pressure distillation of the dehydration kettle, the obtained materials enter a condensation reaction kettle and a closed-loop reaction kettle, and the obtained materials are subjected to condensation and closed-loop reaction with tetrahydrobenzoquinone to obtain a permanent violet pigment crude product.
Examples 2 to 2
The permanent violet synthesis system described in this embodiment is similar to that in embodiment 2-1, and a schematic diagram is shown in fig. 4, which differs from that in embodiment 2-1 in that: and a discharge port of the condensation closed-loop reaction kettle is also connected with a centrifugal machine, the materials obtained after the condensation closed-loop reaction are centrifuged, the obtained mother liquor is introduced into a solvent recovery system, and the obtained permanent violet crude product is introduced into a pigmentation system for further processing.
Examples 2 to 3
The permanent violet synthesis system described in this embodiment is similar to that described in embodiment 2-1, with the following differences: the synthesis system described in this embodiment includes the nitration system described in embodiment 1-1 and the hydrogenation reduction system, and the material inlet of the reduction dehydration kettle is communicated with the material outlet of the reaction liquid receiving kettle.
EXAMPLE 3 continuous Synthesis of permanent Violet
Example 3-1
The permanent violet synthesis system described in example 2-1 was used to synthesize a permanent violet pigment, comprising the following specific steps:
(1) n-ethylation Process
The synthesis process of ethyl carbazole is as follows:
adding 2000kg of liquid alkali (the concentration of NaOH solution is 30%) and 500kg of caustic soda flakes (NaOH) for dissolving, adding 50kg of carbazole and benzyltriethylammonium chloride into a reaction kettle, stirring, slowly dropwise adding bromoethane to keep a small amount of reflux reaction in a condenser, after dropwise adding bromoethane, keeping the temperature at 65-85 ℃ and refluxing until the reaction is finished, heating, distilling and recovering bromoethane to a receiving tank, standing in the kettle after the distillation is finished, layering the lower layer of alkaline water to a liquid alkali pool, and obtaining ethyl carbazole at the upper layer for later use, wherein the purity of the obtained ethyl carbazole is not less than 97.5% through detection.
(2) Nitration process
Preparing an ethyl carbazole o-dichlorobenzene solution: dissolving ethyl carbazole in o-dichlorobenzene to prepare an ethyl carbazole o-dichlorobenzene solution with the molar concentration of 5.0kmol/L for later use.
Preparing a dilute nitric acid solution: dissolving concentrated nitric acid in a proper amount of water to prepare a dilute nitric acid solution with the molar concentration of 10.0kmol/L for later use.
Nitration reaction: starting the microreactor, and using a metering pump which is accurately metered through verification to obtain n-ethyl carbazole: n-nitric acid 1.00: 2.00, the addition amount of an ethyl carbazole solution is 350L/h, the addition amount of a dilute nitric acid solution is 350L/h, the ethyl carbazole o-dichlorobenzene solution and the dilute nitric acid solution are respectively and continuously pumped into a microreactor, the diameter of a gap of the microreactor is 7mm, the length of the microreactor is 1150mm, an outer shell is not moved, the rotating speed of an inner cylinder is 1150 revolutions per minute, the two raw materials are fully reacted in the microreactor through full mixing and efficient mass and heat transfer effects, parameters such as the reaction temperature is strictly controlled to be 41 +/-1 ℃, the reaction time is controlled to be 6 +/-1 min, the motor frequency and the like, the reaction liquid continuously enters a receiving tank from a reactor, the reaction liquid is stirred and cooled to 7 ℃ in the receiving tank, 30% liquid alkali is added to adjust the pH value to be 6.8, and the nitration reaction is completely terminated.
And (3) detecting results of liquid chromatography: the content of the target product 3-nitro-N-ethyl carbazole is 95.0443%, the residual quantity of ethyl carbazole is 0.00%, the content of isomer by-products (such as 2-nitro-N-ethyl carbazole) is 3.1945%, and the content of polynitro by-products (such as 2, 6-dinitro-N-ethyl carbazole) is 0.1802%.
Wherein, the liquid chromatogram detection process is as follows: injecting the material obtained in the reaction liquid receiving tank and a sample prepared by the flowing phase into a liquid chromatograph by using a sample injector, wherein the sample injection amount is as follows: 20 μ L, mobile phase A: acetonitrile, mobile phase B: water, mobile phase ratio: a and B are 70: 30; a chromatographic column: c184.6 × 250mm,5 μm, column temperature: 25 ℃, detection wavelength: 240 nm. The standard substance is 3-nitro-N-ethyl carbazole, the purity is 97.6164%, and the standard substance is purchased from Jiangsu Renxin New Material Co.
The liquid chromatography spectrum of the nitration product obtained in this example is shown in FIG. 5, and the results are shown in the following table:
TABLE 1 liquid chromatogram analysis results of nitration reaction product of example 3-1
Figure BDA0003333515930000121
Figure BDA0003333515930000131
(3) Hydrogenation reduction and condensation closed-loop process
And the material in the receiving tank enters a water diversion tank for diversion, the water phase enters a wastewater treatment system, the oil phase enters a reduction dehydration kettle for reduced pressure distillation to remove residual water, the dehydrated material enters a hydrogenation reduction kettle for hydrogenation reduction, and the material enters the next procedures of condensation, closed loop and the like after reduction, so that the permanent violet crude product is finally obtained.
Wherein, the hydrogenation reduction process comprises the following steps: conveying the material (the addition of 1850kg) dehydrated by the reduction dehydration kettle to a reduction kettle by a pump, adding 5kg of flaky Raney nickel and 30kg of ammonia water (the concentration of 15%) under the stirring condition, introducing nitrogen to replace the air in the reduction kettle, closing a nitrogen inlet valve after detecting that the oxygen content in the reduction kettle meets the safety requirement, heating, opening a hydrogen inlet valve to introduce hydrogen (the flow is 2 m)3And h) carrying out hydrogenation reduction, reacting for 10 hours at 130 ℃, cooling and slowly emptying until the pressure in the kettle is zero after the reduction is finished, and introducing nitrogen for replacing twice. Filtering the material, recovering the catalyst, and feeding the material liquid into the next working procedure.
The condensation ring-closing process comprises the following steps: the reaction material is from a reducing substance (the addition amount is 1500kg) in a hydrogenation kettle (hydrogenation reduction kettle), 7500kg of secondary o-dichlorobenzene is added into a dehydration kettle, the reducing substance in the homogenizing kettle is transferred to the dehydration kettle by vacuum, steam is used for heating and distilling to 130 ℃ through a jacket, a vacuum valve of a receiving tank is slowly opened for negative pressure distillation to 140 ℃, the temperature is reduced to 80 ℃, the vacuum is transferred to a condensation reaction kettle, tetrachlorobenzoquinone (the addition amount is 950kg) and triethylamine (the addition amount is 1050kg) are added dropwise, and the temperature is kept for 10 hours at 40 +/-1 ℃ to obtain a condensation compound. And (3) putting a condensation compound of a reaction material from a condensation kettle into a corresponding closed loop kettle, heating by jacket heat conduction oil, adding benzenesulfonyl chloride (with the addition of 350kg) to cut off front fraction, continuously heating to 175 ℃, carrying out heat preservation and refluxing for 5h, cooling to 130 ℃, and carrying out centrifugal discharging and washing to obtain the dicarbazole dioxazine (a permanent violet crude product).
The synthetic comprehensive yield of the permanent violet product is 75.1 percent, the yield of the N-ethylation reaction is 96.2 percent, the yield of the reduction reaction is 95.1 percent, the yield of the condensation and ring-closure reaction is 92.4 percent, and the calculated nitration reaction yield is 88.8 percent.
Yield refers to the ratio of actual yield to theoretical yield, and is calculated by the formula:
actual yield of M purity/theoretical yield of M100%
Wherein, the comprehensive yield refers to the proportion of the batch yield of the product, namely the permanent violet, in the theoretical yield, M in the calculation formula refers to the permanent violet, and the theoretical yield in the formula is calculated according to the sample amount of the raw material, namely carbazole.
The nitration reaction yield refers to the ratio of the actual yield to the theoretical yield of 3-nitro-N-ethylcarbazole, and the theoretical yield of the target product cannot be determined due to the presence of the nitrated isomer, and is therefore deduced by the following formula: overall yield N-ethyl reaction yield nitration reaction yield reduction reaction yield condensation ring closure reaction yield.
The N-ethyl reaction yield refers to the proportion of the actual yield of the ethyl carbazole to the theoretical yield, M in the calculation formula refers to the ethyl carbazole, and the theoretical yield in the formula is calculated according to the sampling amount of the carbazole serving as the raw material.
The yield of the reduction reaction refers to the proportion of the actual yield of the 3-amino-N-ethyl carbazole to the theoretical yield, M in the calculation formula refers to the 3-amino-N-ethyl carbazole, and the theoretical yield in the formula is calculated according to the sampling amount of the 3-nitro-N-ethyl carbazole.
The condensation ring-closure reaction yield refers to the proportion of the actual yield of the permanent violet to the theoretical yield, M in the calculation formula refers to the permanent violet, and the theoretical yield in the calculation formula is calculated according to the sample amount of the 3-amino-N-ethyl carbazole.
Through detection, the purity of the permanent violet obtained in the embodiment is 98.5 +/-0.5%, and the detection method comprises the following steps: accurately weighing 0.4g of sample (or drying to 0.0001g), placing into a 50ml beaker, adding 30ml (three times) of pyridine for dissolving and rinsing, washing with a sand core funnel (constant weight to 0.0002g), washing with a large amount of distilled water until the filtrate is colorless, adjusting the temperature of an oven to 120 ℃, drying for 1h, and drying the funnel to constant weight. Putting the mixture into a dryer to be cooled to normal temperature and weighing the mixture. Calculating the formula:
purity X ═ G3-G2 ÷ G1 × 100%
Note:
g1: weight of sample (g)
G2: constant weight core crucible weight (gram)
G3: the weight (g) of the filter cake and the sand core crucible which are dried to constant weight after extraction
X: content of permanent Violet RL crude product (%)
Examples 3 to 2
Example 3-2 is similar to example 3-1, except that: the nitration process of this example was:
preparing an ethyl carbazole o-dichlorobenzene solution: dissolving ethyl carbazole in o-dichlorobenzene to prepare an ethyl carbazole o-dichlorobenzene solution with the molar concentration of 2.70kmol/L for later use.
Preparing a dilute nitric acid solution: dissolving concentrated nitric acid in a proper amount of water to prepare a dilute nitric acid solution with the molar concentration of 7.38kmol/L for later use.
Nitration reaction: starting the microreactor, and using a metering pump which is accurately metered through verification to obtain n-ethyl carbazole: n-nitric acid 1.00: the method comprises the following steps of 1.15, wherein the addition amount of an ethyl carbazole solution is 350L/h, the addition amount of a dilute nitric acid solution is 147L/h, the ethyl carbazole o-dichlorobenzene solution and the dilute nitric acid solution are respectively and continuously pumped into a microreactor, the diameter of a gap of the microreactor is 8mm, the length of the microreactor is 1000mm, an outer shell is fixed, the rotating speed of an inner cylinder is 1050 revolutions per minute, the two raw materials are enabled to be fully reacted in the microreactor through full mixing and high-efficiency mass and heat transfer effects, the reaction temperature is strictly controlled to be 55 +/-1 ℃ and the reaction time is 5 +/-1 min, the reaction liquid continuously enters a receiving tank from the reactor, the reaction liquid is stirred and cooled to 7 ℃ in the receiving tank, the pH value is adjusted to 6.8 by adding a NaOH solution (the mass concentration is 30%), and the nitration reaction is completely terminated.
Hydrogenation reduction and condensation closed-loop process
And the material in the receiving tank enters a water diversion tank for diversion, the water phase enters a wastewater treatment system, the oil phase enters a reduction dehydration kettle for reduced pressure distillation to remove residual water, the dehydrated material enters a hydrogenation reduction kettle for hydrogenation reduction, and the material enters the next procedures of condensation, closed loop and the like after reduction, so that the permanent violet crude product is finally obtained.
Wherein, the hydrogenation reduction process comprises the following steps: conveying the material (the addition of 1850kg) dehydrated by the reduction dehydration kettle to a reduction kettle by a pump, adding 2kg of flaky Raney nickel and 20kg of ammonia water (the concentration of 20%) under the stirring condition, introducing nitrogen to replace the air in the reduction kettle, closing a nitrogen inlet valve after detecting that the oxygen content in the reduction kettle meets the safety requirement, heating, opening a hydrogen inlet valve to introduce hydrogen (the flow is 2 m)3H) carrying out hydrogenation reduction, reacting for 8 hours at 120 ℃, cooling and slowly emptying until the pressure in the kettle is zero after the reduction is finished, and introducing nitrogen for replacing twice. Filtering the material, recovering the catalyst, and feeding the material liquid into the next working procedure.
The condensation ring-closing process comprises the following steps: the reaction material is from a reducing substance (the adding amount is 1250kg) in a hydrogenation kettle (hydrogenation reduction kettle), 6500kg of secondary o-dichlorobenzene is added into a dehydration kettle, the reducing substance in the homogenizing kettle is transferred to the dehydration kettle by vacuum, steam is used for raising the temperature and distilling to 130 ℃ through a jacket, a vacuum valve of a receiving tank is slowly opened for negative pressure distillation to 140 ℃, the temperature is reduced to 70 ℃, the vacuum is transferred to a condensation reaction kettle, tetrachlorobenzoquinone (the adding amount is 650kg), triethylamine (the adding amount is 850kg) is dropwise added, and the temperature is kept for 5 hours at 40 +/-1 ℃ to obtain a condensation compound. And (3) putting a condensation compound of a reaction material from a condensation kettle into a corresponding closed loop kettle, heating by jacket heat conduction oil, adding benzenesulfonyl chloride (with the addition of 180kg) to cut off front fraction, continuously heating to 175 ℃, carrying out heat preservation and refluxing for 5h, cooling to 130 ℃, and carrying out centrifugal discharging and washing to obtain the dicarbazole dioxazine (a permanent violet crude product).
Examples 3 to 3
Example 3-3 is similar to example 3-1, except that: the nitration process of this example was:
preparing an ethyl carbazole o-dichlorobenzene solution: dissolving ethyl carbazole in o-dichlorobenzene to prepare an ethyl carbazole o-dichlorobenzene solution with the molar concentration of 1.0kmol/L for later use.
Preparing a dilute nitric acid solution: dissolving concentrated nitric acid in a proper amount of water to prepare a dilute nitric acid solution with the molar concentration of 1.0kmol/L for later use.
Nitration reaction: starting the microreactor, and using a metering pump which is accurately metered through verification to obtain n-ethyl carbazole: n-nitric acid 1.00: the method comprises the following steps of 1.05 mol ratio, 350L/h of ethyl carbazole solution and 368L/h of dilute nitric acid solution, respectively and continuously pumping the ethyl carbazole o-dichlorobenzene solution and the dilute nitric acid solution into a microreactor, wherein the diameter of a gap of the microreactor is 6mm, the length of the microreactor is 1500mm, an outer shell is fixed, the rotating speed of an inner cylinder is 1450 revolutions per minute, the two raw materials are fully reacted in the microreactor through full mixing and efficient mass and heat transfer effects, parameters such as reaction temperature 94 +/-1 ℃, reaction time 6 +/-1 min, motor frequency and the like are strictly controlled, reaction liquid continuously enters a receiving tank from a reactor, the reaction liquid is stirred and cooled to 7 ℃ in the receiving tank, 30% liquid alkali is added to adjust the pH value to 6.8, and the nitration reaction is completely terminated.
Examples 3 to 4
Examples 3-4 are similar to example 3-1, except that: the nitration process of this example was:
preparing an ethyl carbazole o-dichlorobenzene solution: dissolving a certain amount of ethyl carbazole in a proper amount of o-dichlorobenzene to prepare an ethyl carbazole o-dichlorobenzene solution with the molar concentration of 2.5kmol/L for later use.
Preparing a dilute nitric acid solution: dissolving a certain amount of concentrated nitric acid in a proper amount of water to prepare a dilute nitric acid solution with the molar concentration of 5.0kmol/L for later use.
Nitration reaction: starting the microreactor, and using a metering pump which is accurately metered through verification to obtain n-ethyl carbazole: n-nitric acid 1.00: the method comprises the following steps of 1.50 mole ratio, 350L/h of ethyl carbazole solution and 262.5L/h of dilute nitric acid solution, respectively and continuously pumping the ethyl carbazole o-dichlorobenzene solution and the dilute nitric acid solution into a microreactor, wherein the gap diameter of the microreactor is 5mm, the length of the microreactor is 1350mm, an outer shell is fixed, the rotating speed of an inner cylinder is 1250 revolutions per minute, the two raw materials are fully reacted in the microreactor through fully mixing and high-efficiency mass and heat transfer effects, parameters such as reaction temperature of 65 +/-1 ℃, reaction time of 6 +/-1 min, motor frequency and the like are strictly controlled, reaction liquid continuously enters a receiving tank from a reactor, the reaction liquid is stirred and cooled to 7 ℃ in the receiving tank, 30% liquid alkali is added to adjust the pH value to 6.8, and the nitration reaction is completely terminated.
The purity of the permanent violet obtained in example 3-1 to example 3-4 is not less than 98%.
Examples 3 to 5
Examples 3-5 are similar to example 3-1, except that: the nitration process of this example was:
preparing an ethyl carbazole o-dichlorobenzene solution: dissolving a certain amount of ethyl carbazole in a proper amount of o-dichlorobenzene to prepare an ethyl carbazole o-dichlorobenzene solution with the molar concentration of 10.0kmol/L for later use.
Preparing a dilute nitric acid solution: dissolving a certain amount of concentrated nitric acid in a proper amount of water to prepare a dilute nitric acid solution with the molar concentration of 5.0kmol/L for later use.
Nitration reaction: starting the microreactor, and using a metering pump which is accurately metered through verification to obtain n-ethyl carbazole: n-nitric acid 1.00: 0.5, the addition amount of an ethyl carbazole solution is 350L/h, the addition amount of a dilute nitric acid solution is 350L/h, the ethyl carbazole o-dichlorobenzene solution and the dilute nitric acid solution are respectively and continuously pumped into a microreactor, the gap diameter of the microreactor is 5mm, the length of the microreactor is 1350mm, an outer shell is not moved, the rotating speed of an inner cylinder is 1350 revolutions/min, the two raw materials are fully reacted in the microreactor through full mixing and efficient mass and heat transfer effects, parameters such as the reaction temperature is strictly controlled to be 100 +/-1 ℃, the reaction time is controlled to be 6 +/-1 min, the motor frequency and the like, the reaction liquid continuously enters a receiving tank from the reactor, the reaction liquid is stirred and cooled to 7 ℃ in the receiving tank, 30% liquid alkali is added to adjust the pH value to be 6.8, and the nitration reaction is completely terminated.
Examples 3 to 6
Examples 3-6 are similar to example 3-1, except that: the nitration process of this example was:
preparing an ethyl carbazole o-dichlorobenzene solution: dissolving a certain amount of ethyl carbazole in a proper amount of o-dichlorobenzene to prepare an ethyl carbazole o-dichlorobenzene solution with the molar concentration of 1.0kmol/L for later use.
Preparing a dilute nitric acid solution: dissolving a certain amount of concentrated nitric acid in a proper amount of water to prepare a dilute nitric acid solution with the molar concentration of 6.0kmol/L for later use.
Nitration reaction: starting the microreactor, and using a metering pump which is accurately metered through verification to obtain n-ethyl carbazole: n-nitric acid 1.00: 3.0, the addition amount of an ethyl carbazole solution is 350L/h, the addition amount of a dilute nitric acid solution is 175L/h, the ethyl carbazole o-dichlorobenzene solution and the dilute nitric acid solution are respectively and continuously pumped into a microreactor, the diameter of a gap of the microreactor is 8mm, the length of the microreactor is 1100mm, an outer shell is not moved, the rotating speed of an inner column body is 1050 revolutions/minute, the two raw materials are fully reacted in the microreactor through full mixing and high-efficiency mass and heat transfer effects, parameters such as the reaction temperature of 30 +/-1 ℃, the reaction time of 10 +/-1 min, the motor frequency and the like are strictly controlled, the reaction liquid continuously enters a receiving tank from the reactor, the reaction liquid is stirred and cooled to 7 ℃ in the receiving tank, 30% liquid alkali is added to adjust the pH value to 6.8, and the nitration reaction is completely terminated.
Examples 3 to 7
Example 3-7 is similar to example 3-1 except that during the nitration reaction, the outer shell is stationary and the inner cylinder is rotated at 900 rpm.
Examples 3 to 8
Example 3-8 is similar to example 3-1 except that during the nitration reaction, the outer shell is stationary and the inner cylinder is rotated at 1550 rpm.
The analytical results of the nitrated products in the examples are shown in the following table:
TABLE 2 example nitration product analysis results
Figure BDA0003333515930000181
The detection results of the permanent violet synthesis process in the examples are shown in the following table:
TABLE 3 detection results of the permanent violet synthesis process of the examples
Figure BDA0003333515930000182
Figure BDA0003333515930000191
Comparative example
The nitration system of the comparative example is shown in fig. 6 and comprises an alkylation kettle, a nitration kettle and a centrifuge which are sequentially connected, wherein a feeding port of the alkylation kettle is connected with a chlorobenzene metering tank, a feeding port of the nitration kettle is also connected with a dilute nitric acid metering tank, a feeding port of the dilute nitric acid metering tank is connected with an acid preparation kettle, a solid-phase discharge port of the centrifuge obtains 3-nitro-N-ethyl carbazole, a liquid-phase discharge port obtains mother liquor, and the mother liquor is introduced into a solvent recovery system.
The operation process is as follows: carbazole and bromoethane are subjected to alkylation reaction under an alkaline condition to form ethyl carbazole, and after the carbazole alkylation reaction is finished, the carbazole is kept stand to remove a lower-layer alkaline water phase and retain an upper-layer organic phase. Adding chlorobenzene into an alkylation kettle, stirring, and preparing 2.70kmol/L ethyl carbazole chlorobenzene solution.
The nitration kettle was started and stirred, and 1980L of the mixture of ethyl alcohol and chlorobenzene in the alkylation kettle was placed in the nitration kettle. Opening the jacket circulating water to reduce the temperature to below 45 ℃, then opening the inner coil pipe chilled water (the temperature of the chilled water is less than or equal to-15 ℃), controlling the temperature to be 38 +/-1 ℃, slowly dripping dilute nitric acid (the concentration is 7.38kmol/L), and strictly controlling the speed (0.15 m) in the dripping process3H), dropping time (8 h). And after the dripping is finished, keeping the temperature at 38 +/-1 ℃ for 2 hours, and sampling and detecting. After the detection is qualified, cooling to the temperature of 20-25 ℃, and slowly dropwise adding liquid alkali to neutralize until the pH value is 7. Cooling to below 10 deg.C, discharging, centrifuging, washing to obtain 3-nitro-N-ethyl carbazole (nitro compound), packaging nitro compound, sampling, and detecting purity and solid content.
And (3) detecting results of liquid chromatography: the content of the target product 3-nitro-N-ethyl carbazole is 81.3279%, the ethyl carbazole residue is 0.5322%, the content of isomer by-products is 13.1477%, and the content of polynitro by-products is 2.8974%.
The permanent violet synthesis system of the comparative example is shown in fig. 7: the solid-phase discharge port of the centrifuge is connected with a packaging bag, nitro-compounds are discharged after centrifugation and are filled into the packaging bag, then the packaging bag is used for feeding the nitro-compounds into the dehydration kettle, the feeding port of the dehydration kettle is also connected with an o-dichlorobenzene metering tank, and the discharge port of the dehydration kettle is sequentially connected with a hydrogenation reduction kettle, a second dehydration kettle, a condensation reaction kettle, a closed-loop reaction kettle and a centrifuge.
2500L of o-dichlorobenzene was added from an o-dichlorobenzene metering tank to the dehydration kettle, and the dehydration kettle was started to stir. And opening a manhole cover of the dehydration kettle and a tail gas valve of a condenser receiving tank, putting the prepared nitro-compound into the dehydration kettle, and sealing by adding a cover. Opening the atmospheric distillation system, opening a jacket steam valve, and heating to dehydrate to 120 ℃. Slowly opening a vacuum valve (-0.08 to-0.06 mpa) of a receiving tank, carrying out reduced pressure distillation to 130 ℃, closing the vacuum valve when the distillate is anhydrous, opening a vent valve of the receiving tank, cooling to (90 to 100 ℃), pressing nitrogen into a hydrogenation reduction kettle for hydrogenation reduction, feeding the material into a dehydration kettle after the reduction is finished, adding 6500 to 7500 kilograms of secondary o-dichlorobenzene for reduced pressure distillation, and feeding the product into a condensation reaction kettle and a closed-loop reaction kettle for the next procedure to finally obtain a permanent violet crude product. The comprehensive yield of the product synthesis is 58.60%, the yield of the N-ethylation reaction is 95.9%, the yield of the reduction reaction is 95.2%, the yield of the condensation and ring-closure reaction is 92.3%, and the estimated nitration reaction yield is 69.4%.
In conclusion, the nitration system and the synthesis system can effectively avoid heat accumulation, greatly improve the intrinsic safety of nitration reaction, improve the conversion rate of raw materials and effectively improve the product yield.

Claims (11)

1. The nitration system for continuously synthesizing the permanent violet is characterized by comprising an ethyl carbazole dissolving kettle, a microreactor and a reaction liquid receiving tank which are sequentially connected, wherein the ethyl carbazole dissolving kettle is provided with an ethyl carbazole feeding port and an o-dichlorobenzene feeding port, the microreactor is provided with a nitric acid feeding port, and a discharge port of the reaction liquid receiving tank is used for outputting a nitration product containing 3-nitro-N-ethyl carbazole;
the micro-reactor comprises a shell and an inner cylinder arranged inside the shell, a micro-reaction channel is arranged between the inner cylinder and the shell, the micro-reaction channel penetrates through the shell to form a micro-reactor feeding port and a discharging port, and at least one of the inner cylinder and the shell is connected with a driving device.
2. The nitration system according to claim 1, wherein the micro reaction channel has a diameter of less than 10mm, preferably 5-8mm, and a length of 1000-1500mm, preferably 1300-1500 mm.
3. The nitration system of claim 1 or 2, wherein the relative rotational speed of the outer microreactor housing and the inner cartridge is 900-.
4. The nitration system of any one of claims 1 to 3, wherein a discharge port of the reaction liquid receiving kettle is connected with a water diversion tank, a discharge port of the water diversion tank is provided with a water phase discharge port and an oil phase discharge port, and the oil phase discharge port is used for outputting nitration products containing 3-nitro-N-ethylcarbazole.
5. A synthetic system for continuously synthesizing permanent violet, which is characterized by comprising the nitration system and the hydrogenation reduction system of any one of claims 1 to 4, wherein the hydrogenation reduction system comprises a reduction dehydration kettle, a hydrogenation reduction kettle, a dehydration kettle, a condensation reaction kettle and a closed-loop reaction kettle which are connected in sequence.
6. A nitration method for continuously synthesizing permanent violet is characterized in that a nitration system of any one of claims 1 to 3 is started, ethyl carbazole and o-dichlorobenzene are added into an ethyl carbazole dissolving kettle and mixed to form a mixed solution of the ethyl carbazole and the o-dichlorobenzene, the mixed solution is introduced into a microreactor, dilute nitric acid is added into the microreactor, and after the reaction is finished, the obtained reaction solution is introduced into a reaction solution receiving tank to be cooled to obtain a nitration product containing 3-nitro-N-ethyl carbazole.
7. The nitration process of claim 6, wherein the microreactor feed inlet has a molar ratio of ethyl carbazole to nitric acid of 1.00: (1.01 to 3.00), preferably 1.00: (1.01-2.00).
8. The nitration process according to claim 6 or 7, wherein the reaction temperature in the microreactor is from 30 to 100 ℃, preferably from 40 to 95 ℃.
9. The nitration method according to any one of claims 6 to 8, wherein the discharge port of the reaction liquid receiving kettle is connected with a water diversion tank, the discharge port of the water diversion tank is provided with a water phase discharge port and an oil phase discharge port, and the oil phase discharge port obtains a nitration product containing 3-nitro-N-ethylcarbazole;
introducing a product obtained from a discharge port of the reaction liquid receiving kettle into a water diversion tank for water diversion, introducing an obtained water phase material into a wastewater treatment system, and obtaining an oil phase material containing a nitration product of 3-nitro-N-ethyl carbazole.
10. The nitration process according to any one of claims 6 to 9, wherein in the nitration process, the nitration yield is 80 to 90% and the content of the principal product of the nitration reaction, i.e. the content of 3-nitro-ethylcarbazole in the nitrated product, is 80 to 95%, preferably 90 to 95%.
11. A synthetic process for the continuous synthesis of permanent violet, comprising the nitration process according to any one of claims 6 to 10, further comprising the steps of: the synthesis system of claim 5 is started, a material containing 3-nitro-N-ethyl carbazole is introduced into a reduction dehydration kettle, water is removed after reduced pressure distillation, the obtained material is introduced into a hydrogenation reduction kettle for hydrogenation reduction, the dehydrated material enters a condensation reaction kettle to undergo condensation reaction with tetrahydrobenzoquinone, the product is introduced into a closed-loop reaction kettle, benzenesulfonyl chloride is added to cut off the front fraction, and the permanent violet pigment is obtained.
CN202111287112.6A 2021-11-02 2021-11-02 Nitration system, synthesis system and method for continuously synthesizing permanent violet Active CN113941303B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN202111287112.6A CN113941303B (en) 2021-11-02 2021-11-02 Nitration system, synthesis system and method for continuously synthesizing permanent violet
JP2022083748A JP7570752B2 (en) 2021-11-02 2022-05-23 Nitrification system, synthesis system and method for continuous synthesis of permanent violet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111287112.6A CN113941303B (en) 2021-11-02 2021-11-02 Nitration system, synthesis system and method for continuously synthesizing permanent violet

Publications (2)

Publication Number Publication Date
CN113941303A true CN113941303A (en) 2022-01-18
CN113941303B CN113941303B (en) 2022-07-12

Family

ID=79337544

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111287112.6A Active CN113941303B (en) 2021-11-02 2021-11-02 Nitration system, synthesis system and method for continuously synthesizing permanent violet

Country Status (2)

Country Link
JP (1) JP7570752B2 (en)
CN (1) CN113941303B (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140243556A1 (en) * 2011-10-14 2014-08-28 Council Of Scientific & Industrial Research Continuous two step flow synthesis of m-amino acetophenone
CN111233746A (en) * 2020-02-27 2020-06-05 泰兴先先化工有限公司 Method for preparing oxime ester photoinitiator containing nitro group by nitration in micro-channel
CN111790331A (en) * 2020-07-29 2020-10-20 贵州微化科技有限公司 Relative motion annular gap micro-reactor
CN112724700A (en) * 2021-01-22 2021-04-30 内蒙古彩晶新材料科技有限公司 Process for synthesizing permanent violet RL by one-pot method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009062342A (en) * 2007-09-08 2009-03-26 National Institute Of Advanced Industrial & Technology Method for selecting nitration solvent for solid organic compound and method for nitration reaction of substrate organic compound

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140243556A1 (en) * 2011-10-14 2014-08-28 Council Of Scientific & Industrial Research Continuous two step flow synthesis of m-amino acetophenone
CN111233746A (en) * 2020-02-27 2020-06-05 泰兴先先化工有限公司 Method for preparing oxime ester photoinitiator containing nitro group by nitration in micro-channel
CN111790331A (en) * 2020-07-29 2020-10-20 贵州微化科技有限公司 Relative motion annular gap micro-reactor
CN112724700A (en) * 2021-01-22 2021-04-30 内蒙古彩晶新材料科技有限公司 Process for synthesizing permanent violet RL by one-pot method

Also Published As

Publication number Publication date
JP7570752B2 (en) 2024-10-22
JP2023068610A (en) 2023-05-17
CN113941303B (en) 2022-07-12

Similar Documents

Publication Publication Date Title
CN107337618B (en) Production method for simultaneously improving purity and yield of metformin hydrochloride
CN101624364A (en) CTP synthesis technology of rubber scorch retarder and device thereof
CN1070472C (en) Process for the adiabatic preparation of monoitrotoluenes
CN101328145A (en) Method for producing N- ethyl carbazole
CN113582867A (en) Continuous synthesis method of 2-acetamido-5-nitrobenzyl ether
CN112209793A (en) A kind of Friedel-Crafts alkylation reaction product and continuous synthesis method thereof
CN113941303B (en) Nitration system, synthesis system and method for continuously synthesizing permanent violet
JP7702429B2 (en) Acylation liquid and process for continuous synthesis of acylnaphthalenes using the acylation liquid
CN105732327A (en) Method and device for preparing ethylene glycol antimony through microwave reaction
CN102408430A (en) Synthetic process and special equipment for substituted bis [tetraphenylporphinatoiron]
CN109180537B (en) Method for preparing 3-chloro-p-toluidine-6-sulfonic acid by liquid phase baking method
CN104250218B (en) A kind of tert-butyl acrylamide sulfonate production method
CA2118379C (en) Preparation of acetoacetarylamides
CN113694858B (en) Continuous nitration reaction device and method for benzene ring nitration
CN115043734B (en) Continuous production process of 2,4 &#39;-trichloro-2&#39; -nitrodiphenyl ether
CN118084718A (en) Synthesis method for continuously preparing azobenzene intermediate compound and benzotriazole light stabilizer
CN214991232U (en) Device for alkylation continuous reaction of m-cresol and/or p-cresol
CN115353481A (en) Catalytic synthesis method of cis-1, 2,3, 6-tetrahydrophthalimide
CN113105332A (en) Method for preparing eltrombopag nitration intermediate in micro-channel continuous flow reactor
CN107304166A (en) The industrialized process for preparing of naphthalidine
CN219701859U (en) Reaction system of dye intermediate
CN113769683A (en) A kind of short-flow continuous preparation system and method of laurolactam
CN113968778B (en) Device and process for continuous water-out extraction phase separation of 2- (4&#39; -ethylbenzoyl) benzoic acid closed-loop liquid by one-step method
CN114426446B (en) Method for preparing isopropylbiphenyl in continuous flow microreactor
CN104402732A (en) Technology for purifying 2, 4-diaminotoluene by recrystallization method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
CP01 Change in the name or title of a patent holder

Address after: 242000 No.70 Industrial Road, Xuancheng City, Anhui Province

Patentee after: Anhui Shenlanhua Color Material Co.,Ltd.

Address before: 242000 No.70 Industrial Road, Xuancheng City, Anhui Province

Patentee before: Anhui shenlanhua color material Co.,Ltd.

CP01 Change in the name or title of a patent holder