CN114907181B - Device for sandmeyer reaction and method for continuously preparing 2, 6-diethyl-4-methyl bromobenzene - Google Patents
Device for sandmeyer reaction and method for continuously preparing 2, 6-diethyl-4-methyl bromobenzene Download PDFInfo
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- CN114907181B CN114907181B CN202110178814.4A CN202110178814A CN114907181B CN 114907181 B CN114907181 B CN 114907181B CN 202110178814 A CN202110178814 A CN 202110178814A CN 114907181 B CN114907181 B CN 114907181B
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- 238000000034 method Methods 0.000 title claims abstract description 44
- QWIITRRSNVBPDK-UHFFFAOYSA-N 2-bromo-1,3-diethyl-5-methylbenzene Chemical compound CCC1=CC(C)=CC(CC)=C1Br QWIITRRSNVBPDK-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 238000000297 Sandmeyer reaction Methods 0.000 title claims abstract description 11
- 238000005893 bromination reaction Methods 0.000 claims abstract description 137
- 230000031709 bromination Effects 0.000 claims abstract description 133
- 238000005406 washing Methods 0.000 claims abstract description 114
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 99
- 239000002994 raw material Substances 0.000 claims abstract description 89
- 238000003860 storage Methods 0.000 claims abstract description 75
- 238000006193 diazotization reaction Methods 0.000 claims abstract description 53
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 claims abstract description 48
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 41
- 238000002156 mixing Methods 0.000 claims abstract description 36
- 238000006243 chemical reaction Methods 0.000 claims abstract description 31
- 239000007864 aqueous solution Substances 0.000 claims abstract description 29
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 claims abstract description 16
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 claims abstract description 16
- 229910052794 bromium Inorganic materials 0.000 claims abstract description 16
- 239000000047 product Substances 0.000 claims abstract description 16
- JHJLBTNAGRQEKS-UHFFFAOYSA-M sodium bromide Chemical compound [Na+].[Br-] JHJLBTNAGRQEKS-UHFFFAOYSA-M 0.000 claims description 54
- 239000002351 wastewater Substances 0.000 claims description 53
- 239000000243 solution Substances 0.000 claims description 37
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical group Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 claims description 36
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 claims description 34
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 33
- 238000001816 cooling Methods 0.000 claims description 24
- OIXUMNZGNCAOKY-UHFFFAOYSA-N 2,6-diethyl-4-methylaniline Chemical compound CCC1=CC(C)=CC(CC)=C1N OIXUMNZGNCAOKY-UHFFFAOYSA-N 0.000 claims description 19
- 229910000042 hydrogen bromide Inorganic materials 0.000 claims description 18
- 235000010288 sodium nitrite Nutrition 0.000 claims description 17
- 238000003756 stirring Methods 0.000 claims description 14
- 238000000605 extraction Methods 0.000 claims description 11
- 239000002904 solvent Substances 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 9
- UHZZMRAGKVHANO-UHFFFAOYSA-M chlormequat chloride Chemical group [Cl-].C[N+](C)(C)CCCl UHZZMRAGKVHANO-UHFFFAOYSA-M 0.000 claims description 8
- 239000010408 film Substances 0.000 claims description 7
- 239000011552 falling film Substances 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims description 2
- 238000004807 desolvation Methods 0.000 claims 1
- 239000012954 diazonium Substances 0.000 abstract description 9
- 150000001989 diazonium salts Chemical class 0.000 abstract description 9
- 238000004519 manufacturing process Methods 0.000 abstract description 8
- 239000000575 pesticide Substances 0.000 abstract description 4
- 238000011112 process operation Methods 0.000 abstract description 3
- 238000009825 accumulation Methods 0.000 abstract description 2
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 238000003786 synthesis reaction Methods 0.000 abstract description 2
- 239000012043 crude product Substances 0.000 description 11
- 238000004821 distillation Methods 0.000 description 8
- 239000012071 phase Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 238000007599 discharging Methods 0.000 description 4
- 238000006386 neutralization reaction Methods 0.000 description 4
- 239000012074 organic phase Substances 0.000 description 4
- 238000010992 reflux Methods 0.000 description 4
- 239000005597 Pinoxaden Substances 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 238000000998 batch distillation Methods 0.000 description 3
- 238000010923 batch production Methods 0.000 description 3
- 238000010612 desalination reaction Methods 0.000 description 3
- 238000004817 gas chromatography Methods 0.000 description 3
- MGOHCFMYLBAPRN-UHFFFAOYSA-N pinoxaden Chemical compound CCC1=CC(C)=CC(CC)=C1C(C1=O)=C(OC(=O)C(C)(C)C)N2N1CCOCC2 MGOHCFMYLBAPRN-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 210000003298 dental enamel Anatomy 0.000 description 2
- 238000011033 desalting Methods 0.000 description 2
- 230000002363 herbicidal effect Effects 0.000 description 2
- 239000004009 herbicide Substances 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- JFJWVJAVVIQZRT-UHFFFAOYSA-N 2-phenyl-1,3-dihydropyrazole Chemical compound C1C=CNN1C1=CC=CC=C1 JFJWVJAVVIQZRT-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 206010024769 Local reaction Diseases 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 239000012267 brine Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001212 derivatisation Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000007306 functionalization reaction Methods 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 230000002427 irreversible effect Effects 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 150000002829 nitrogen Chemical class 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C245/00—Compounds containing chains of at least two nitrogen atoms with at least one nitrogen-to-nitrogen multiple bond
- C07C245/20—Diazonium compounds
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to the field of pesticide synthesis, and discloses a device for a sandmeyer reaction and a method for continuously preparing 2, 6-diethyl-4-methyl bromobenzene by using the device, wherein the device comprises the following steps: a premixing unit for mixing the reaction raw materials and performing diazotization reaction; a storage unit connected to the pre-mixing unit for storing diazotization reaction products; the lower part of the reverse bromination unit is connected with the storage unit, and the upper part of the reverse bromination unit is connected with a conveying unit for conveying the bromine source aqueous solution into the reverse bromination unit, and the reverse bromination unit is used for enabling diazotization reaction products to reversely contact with the bromine source aqueous solution and carry out bromination; and the lower part of the water washing unit is connected with the upper part of the reverse bromination unit, and the upper part of the water washing unit is connected with a conveying unit for conveying washing water into the water washing unit and is used for washing bromide. By using the device, the production process is safe and efficient, the accumulation of high-critical diazonium salt is not caused, the problem of high viscosity of a kettle type reaction system is solved, the product yield and purity are high, and the process operation is simple and efficient.
Description
Technical Field
The invention relates to the field of pesticide synthesis, in particular to a device for a sandmeyer reaction and a method for continuously preparing 2, 6-diethyl-4-methyl bromobenzene.
Background
The 2, 6-diethyl-4-methyl bromobenzene is a key intermediate of a novel phenyl pyrazoline herbicide pinoxaden, and has the following structural formula:
2, 6-diethyl-4-methyl bromobenzene is a key intermediate for synthesizing pesticide pinoxaden, and carbon-bromine bonds on the structure can be used for further functionalization to form fluoride, so that the compound can be applied to the fields of pesticides and medicines. Both CN109134187A, CN106928253A, CN102395546A and CN108864144A were used to prepare 2, 6-diethyl-4-methyl bromobenzene by diazotizing and then brominating 2, 6-diethyl-4-methylaniline in a batch process (Sandmeyer, sandmeyer reaction). These methods all suffer from significant drawbacks:
1) After diazotization reaction, a large amount of diazonium salt is accumulated in the reaction kettle, and explosion is caused by easy decomposition of the diazonium salt, so that great potential safety hazard exists in the industrial production process, and the productivity of 2, 6-diethyl-4-methyl bromobenzene is limited to be improved;
2) In order to ensure safe production, the energy consumption is increased at a low temperature (-20 ℃) when the diazonium salt is prepared, and meanwhile, the temperature is increased and lowered repeatedly in the production process, so that the operation is complicated, and the production efficiency is reduced;
3) Firstly preparing diazonium salt corresponding to 2, 6-diethyl-4-methylaniline, then slowly dripping the diazonium salt into a brominating reagent for brominating reaction, wherein a plurality of reaction kettles are required to be mutually matched for operation in the process, a batch usually needs a plurality of hours, the process operation is complicated, the production time is long, and the production efficiency is low;
4) After the diazonium salt is prepared, the diazonium salt is usually required to be slowly dripped into a brominating reagent for brominating reaction due to higher temperature of the brominating reaction in the next step, the reaction time is long, the reaction selectivity is easy to influence, and the content of byproducts is higher.
Therefore, a preparation method for producing 2, 6-diethyl-4-methyl bromobenzene with high content needs to be found, which is safe and efficient in production, simple in operation and easy for large-scale production, and has important significance for the industrial production of the herbicide pinoxaden.
Disclosure of Invention
The invention aims to overcome the problems in the prior art and provide a device for the sandmeyer reaction and a method for continuously preparing 2, 6-diethyl-4-methyl bromobenzene.
In order to achieve the above object, an aspect of the present invention provides an apparatus for sandmeyer reaction, comprising:
a premixing unit for mixing the reaction raw materials and performing diazotization reaction;
A storage unit connected to the pre-mixing unit for storing diazotization reaction products;
The lower part of the reverse bromination unit is connected with the storage unit, and the upper part of the reverse bromination unit is connected with a conveying unit for conveying the bromine source aqueous solution into the reverse bromination unit, and the reverse bromination unit is used for enabling diazotization reaction products to reversely contact with the bromine source aqueous solution and carry out bromination;
and the lower part of the water washing unit is connected with the upper part of the reverse bromination unit, and the upper part of the water washing unit is connected with a conveying unit for conveying washing water into the water washing unit and is used for washing bromide.
Preferably, the pre-mixing unit has a plurality of conveying units for feeding raw materials into the pre-mixing unit for mixing reaction.
Preferably, the pre-mix unit has 3 feed units.
Preferably, the delivery unit is a double plunger metering pump or a double diaphragm metering pump.
Preferably, the pre-mix unit is a parallel tube reactor or a spiral tube reactor.
Preferably, the pre-mix unit has a cooling unit for cooling the reaction mass.
Preferably, the cooling unit is a cooling jacket.
Preferably, the storage unit is a storage tank with a cooling jacket.
Preferably, the storage unit has a stirring unit.
Preferably, the number of the storage units is plural, preferably 2-3.
Preferably, a material conveying unit is arranged between the storage unit and the reverse bromination unit and is used for conveying diazotization reaction products into the reverse bromination unit.
Preferably, the material conveying unit is a double-plunger metering pump or a double-diaphragm metering pump.
Preferably, the reverse bromination unit is a reverse bromination column.
Preferably, the reverse bromination unit is a paddle rotary bromination tower, a reciprocating sieve plate bromination tower or a packed tower; more preferably, the reverse bromination unit is a paddle rotary bromination column.
Preferably, the bottom of the reverse bromination unit is connected with a bromination waste water storage tank, and the bromination waste water storage tank is used for temporary storage treatment of the water phase at the bottom of the reverse bromination unit.
Preferably, a pi-shaped pipe is arranged between the reverse bromination unit and the bromination waste water storage tank, and is used for connecting the bottom of the reverse bromination unit with the bromination waste water storage tank and controlling the liquid level in the reverse bromination unit.
Preferably, after the wastewater in the bromination wastewater storage tank is concentrated by the concentrating device, the wastewater is returned to the reverse bromination unit through the conveying unit to be used as bromination raw material. Preferably, the water washing unit is a water washing tower, a paddle type rotary extraction tower or a centrifugal extractor.
Preferably, a conveying unit is arranged between the water storage tank and the water washing unit, and is used for conveying water to the upper part of the water washing unit for washing bromide solution from the upper part of the reverse bromination unit.
Preferably, the delivery unit is a double plunger metering pump or a double diaphragm metering pump.
Preferably, a conveying unit is arranged between the reverse bromination unit and the washing unit, and is used for conveying bromide solution to the bottom of the washing unit and performing reverse washing.
Preferably, the bottom of the washing unit is connected with a washing wastewater receiving tank for temporary storage treatment of the water phase at the bottom of the washing unit.
Preferably, a pi-shaped pipe is arranged between the washing unit and the washing wastewater receiving tank, and is used for connecting the bottom of the washing unit with the washing wastewater receiving tank and controlling the liquid level in the washing unit.
Preferably, the device is also provided with a solvent removing unit, and the feed inlet of the solvent removing unit is connected with the top discharge outlet of the washing unit through a preheating unit and is used for removing solvent from the washing product.
Preferably, the solvent removing unit is one or more of a scraper evaporator, a falling film evaporator and a rising film evaporator; more preferably, the desolventizing unit is a wiped film evaporator.
Preferably, the desolventizing unit is connected in sequence to a crude bromide receiving tank, a rectifying unit and a bromide product receiving tank.
The invention also provides a method for continuously preparing 2, 6-diethyl-4-methyl bromobenzene, wherein the method is carried out by using the device disclosed by the invention, and comprises the following steps:
1) Continuously feeding the raw material A, the raw material B and the raw material C into a premixing unit through a conveying unit respectively for mixing and diazotizing;
2) Continuously feeding the diazotization reaction product into a storage unit for further diazotization reaction;
3) Continuously feeding the diazotization reaction product into the lower part of a reverse bromination unit, continuously feeding the raw material D into the upper part of the reverse bromination unit through a conveying unit, and enabling the raw material D to reversely contact with the diazotization reaction product for bromination;
4) Continuously feeding bromide solution from the upper part of the reverse bromination unit to the lower part of the water washing unit, continuously feeding raw material E to the upper part of the water washing unit through the conveying unit, and reversely washing the raw material E and the bromide solution;
the raw material A is a toluene solution of 2, 6-diethyl-4-methylaniline, the raw material B is a hydrogen bromide aqueous solution, the raw material C is a sodium nitrite aqueous solution, the raw material D is a sodium bromide aqueous solution, and the raw material E is water.
Preferably, the concentration of the toluene solution of 2, 6-diethyl-4-methylaniline is 0.5-0.75mol/L.
Preferably, the concentration of the aqueous hydrogen bromide solution is 7.5-10mol/L.
Preferably, the concentration of the sodium nitrite aqueous solution is 5.5-8mol/L.
Preferably, the concentration of the sodium bromide aqueous solution is 8.5-11mol/L.
Preferably, the feed rates of feed a, feed B and feed C are such that the molar ratio of 2, 6-diethyl-4-methylaniline, hydrogen bromide and sodium nitrite is 1:2-4:1.05-1.25.
Preferably, the feed D is fed to the reverse bromination unit at a rate such that the molar ratio of diazotisation reaction product to sodium bromide, calculated on a theoretical basis, is 1:6.5-7.9.
Preferably, the water phase at the bottom of the reverse bromination unit is sent to a bromination waste water storage tank and is sent to a concentration treatment device for concentration treatment, and the concentrated sodium bromide aqueous solution is sent to the upper part of the reverse bromination unit as a bromine source for bromination.
Preferably, the concentration of sodium bromide in the concentrated aqueous sodium bromide solution is 8.5-11mol/L.
Preferably, the method further comprises removing the solvent from the washed bromide in a desolventizing unit.
Through the technical scheme, the device for the sandmeyer reaction and the method for continuously preparing the 2, 6-diethyl-4-methyl bromobenzene can be provided, which are simple in equipment arrangement, small in acid consumption (8-10 equivalents of acid used in the intermittent method), small in pollution (less in acid consumption and less in waste water), uniform in reaction temperature distribution (large in continuous tube type compared with the intermittent kettle type heat exchange area, and capable of avoiding local reaction overheating), controllable, uniform in material mixing, stable and controllable in reaction residence time. Compared with a batch process, the batch process has long retention time of diazonium salt, and irreversible self-coupling is easy to occur.
The invention adopts continuous reaction, namely diazotization (unstable diazotization) directly enters the subsequent bromination reaction and is converted into stable bromide, and continuous automatic layering and continuous automatic water washing are adopted. The volume utilization rate of the continuous reaction is high, and the high strength, the high efficiency and the microminiaturization of the reactor can be realized.
The device provided by the invention has the advantages of safe and efficient production process, no accumulation of high-critical nitrogen salt, high product yield and purity, and simple and efficient process operation, and solves the problem of high viscosity of a kettle-type reaction system.
Drawings
FIG. 1 is a schematic view of an apparatus for the sandmeyer reaction according to the present invention.
Description of the reference numerals
1. Premix unit 2, storage unit 3, reverse bromination unit 4, washing unit 5, bromination waste water storage tank 6, desolventizing unit 7, water storage tank 8, washing waste water receiving tank 9, preheating unit 10, condenser 11, transporting unit 12, bromide crude product receiving tank 13, bromide product receiving tank 14, rectifying unit 15, stirring unit 16, concentrating device 17, neutralization, concentrating and desalting device 22, stirring unit 21, transporting unit 31, transporting unit 33, pi-type pipe 41, pi-type pipe 51, transporting unit
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
As shown in fig. 1, the present invention provides an apparatus for sandmeyer reaction, wherein the apparatus comprises:
a premixing unit 1 for mixing the reaction raw materials and performing diazotization reaction;
A storage unit 2 connected to the pre-mixing unit (1) for storing diazotization reaction products;
A reverse bromination unit 3, the lower part of which is connected with the storage unit 2, and the upper part of which is connected with a conveying unit 31 for conveying bromine source aqueous solution into the storage unit, and the conveying unit is used for reversely contacting and brominating diazotization reaction products with the bromine source aqueous solution;
the water washing unit 4 has a lower portion connected to an upper portion of the reverse bromination unit 3, and a delivery unit 51 for delivering washing water thereto is connected to the upper portion for washing bromide with water.
According to the present invention, the pre-mixing unit (1) may have a plurality of conveying units 11 for respectively feeding various kinds of raw materials into the pre-mixing unit 1 for mixing reaction according to the kinds of the raw materials for reaction; preferably, the pre-mix unit 1 has 3 feed units.
The conveying means 11 may be, for example, a plunger type metering pump, a mechanical diaphragm metering pump, a hydraulic diaphragm metering pump, or an electromagnetic diaphragm metering pump; preferably a double plunger metering pump or a double diaphragm metering pump.
According to the present invention, the pre-mixer unit 1 is used for mixing the reaction raw materials and performing the diazotization reaction, and the pre-mixer unit 1 may be a parallel tube reactor, a spiral tube reactor, or the like as long as the above-described functions can be achieved.
Furthermore, in order to better control the reaction temperature and to increase safety, it is preferred that the pre-mix unit 1 has a cooling unit for cooling the reaction mass.
As the above-mentioned cooling unit, various cooling devices generally used in the art may be used, and preferably, the cooling unit is a cooling jacket or an external cooling coil or the like. The cooling medium may be, for example, chilled brine, an aqueous glycol solution, or the like.
In a preferred embodiment of the invention, the pre-mix unit 1 has a cooling jacket, i.e. the pre-mix unit 1 is preferably a parallel tube reactor with cooling jacket or a spiral tube reactor with cooling jacket or the like.
According to the invention, the memory unit 2 is used for storing diazotisation reaction products. Since the diazotization reaction is faster, the reaction is generally completed in substantially all of the mixing reaction in the pre-mixing unit 1, and in the present invention, by providing the storage unit 2 between the pre-mixing unit 1 and the inverse bromination unit 3, on the one hand, a small amount of raw materials which are not subjected to the diazotization reaction can be further reacted in the storage unit 2, so that the diazotization reaction is sufficiently performed; on the other hand, the storage unit 2 is used as a buffer storage unit of diazotization reaction products, so that the diazotization reaction products can be further ensured to be stably fed into the reverse bromination unit 3, and the potential safety hazard is reduced.
The storage unit 2 may be, for example, a storage tank having a cooling jacket.
In addition, in order to make the diazotization reaction product more uniform, it is preferable that the storage unit 2 has a stirring unit 22. The stirring unit 22 may be any of various stirring devices used in the art for stirring, such as a stirring paddle, and the like, and will not be described here.
According to the present invention, preferably, the number of the storage units 2 is plural, preferably 2-3. By providing a plurality of memory cells 2, the cells can be used alternately, thereby ensuring the completion of the diazotization reaction.
According to the invention, preferably, a feeding unit 21 is provided between the storage unit 2 and the inverse bromination unit 3 for feeding diazotization reaction products into the inverse bromination unit.
The conveying means 21 may be, for example, a plunger type metering pump, a mechanical diaphragm metering pump, a hydraulic diaphragm metering pump, or an electromagnetic diaphragm metering pump; preferably a double plunger metering pump or a double diaphragm metering pump.
According to the present invention, the reverse bromination unit 3 may be various reverse bromination towers used in the art for reverse bromination, preferably, the reverse bromination unit 3 is a paddle type rotary bromination tower (the tower is divided into a plurality of sections by an annular partition plate, and paddles are arranged on the rotating shaft of each section), a reciprocating sieve type bromination tower or a packed tower.
In the present invention, by feeding a bromine source having a large density from the upper portion of the inverse bromination unit 3 and a diazotization reaction product having a smaller density from the lower portion, the bromine source having a large density relatively moves toward the bottom and the diazotization reaction product having a smaller density relatively moves toward the top in the inverse bromination unit 3 due to the difference in density, so that the bromine source and the diazotization reaction product are reversely contacted and bromination reaction is performed in the inverse bromination unit 3.
In order to sufficiently perform the contact and the bromination reaction, the reverse bromination unit 3 preferably has a stirring unit 15, and a blade-type rotary bromination tower can be used as the reverse bromination unit 3 having the stirring unit 15.
According to the invention, preferably, the bottom of the reverse bromination unit 3 is connected with a bromination waste water storage tank 5 for temporary storage treatment of water phase at the bottom of the reverse bromination unit 3; more preferably, a pi-shaped pipe 33 is arranged between the reverse bromination unit 3 and the bromination waste water storage tank 5, and is used for connecting the bottom of the reverse bromination unit 3 and the bromination waste water storage tank 5 and controlling the liquid level in the reverse bromination unit 3. The pi-tube 33 allows for adjustment of the liquid level height, and the contact time of the bromine source and the diazotization reaction product can be easily adjusted by the pi-tube 33.
According to the present invention, it is preferable that a concentrating unit 16 for concentrating the wastewater in the bromination wastewater tank 5 is provided between the bromination wastewater tank 5 and the transporting unit 31. The concentration unit 16 may be, for example, a distillation apparatus of various types commonly used in the art; preferably, the bromination waste water is concentrated and then fed into a raw material D storage tank as bromination raw material, and is fed into the reverse bromination unit 3 through a conveying unit 31 to be used as bromination raw material.
According to the invention, preferably, a water storage tank 7 is connected to the top of the washing unit 4; more preferably, a conveying unit 51 is provided between the water storage tank 7 and the water washing unit 4 for feeding new process water or reuse water (water obtained by neutralizing, desalting and distilling the waste water of the washing waste water storage tank 8) to the upper portion of the water washing unit 4 for washing the bromide solution from the upper portion of the reverse brominating unit 3.
Preferably, the water washing unit 4 has a stirring unit 15.
The washing unit 4 may be, for example, various devices commonly used in washing in the art, and may be, for example, a washing tower, a paddle type rotary extraction tower, a centrifugal extractor, or the like.
The conveying unit 51 may be, for example, a plunger type metering pump, a mechanical diaphragm metering pump, a hydraulic diaphragm metering pump, or an electromagnetic diaphragm metering pump; preferably a double plunger metering pump or a double diaphragm metering pump.
According to the present invention, preferably, a conveying unit 32 is provided between the reverse bromination unit 3 and the water washing unit 4, for feeding bromide to the bottom of the water washing unit 4 and performing reverse water washing.
The delivery unit 32 may be, for example, a plunger type metering pump, a mechanical diaphragm metering pump, a hydraulic diaphragm metering pump, or an electromagnetic diaphragm metering pump; preferably a double plunger metering pump or a double diaphragm metering pump.
According to the present invention, preferably, a wash wastewater receiving tank 8 is connected to the bottom of the washing unit 4, for temporary storage of the water phase at the bottom of the washing unit 4. Preferably, the wastewater in the washing wastewater receiving tank 8 is treated by a neutralization, concentration and desalination treatment device 17, and the produced water (neutral water) is returned as washing water E to the washing unit 4.
According to the present invention, preferably, a pi-shaped pipe 41 is provided between the washing unit 4 and the washing wastewater receiving tank 8, connects the bottom of the washing unit 4 and the washing wastewater receiving tank 8, and is used to control the liquid level in the washing unit 4. In addition, the pi-shaped pipe 41 can drain the water phase at the bottom, and can adjust the water washing time conveniently by adjusting the liquid level height.
According to the invention, the device is preferably further provided with a desolventizing unit 6, the feed inlet of which is connected with the top discharge outlet of the washing unit 4 through a preheating unit 9, for desolventizing the washing product.
The desolventizing unit 6 may be, for example, a wiped film evaporator, a falling film evaporator, a rising film evaporator, or the like.
Preferably, the desolventizing unit 6 has a scraper evaporator of a stirring unit 15.
According to the present invention, preferably, a condenser 10 is connected to the top of the desolventizing unit 6 for cooling the solvent to recover the solvent.
According to the present invention, preferably, the desolventizing unit 6 is connected to a bromide crude receiving tank 12, a rectifying unit 14, and a bromide product receiving tank 13 in this order. The bromide crude product receiving tank 12 is used for receiving bromide crude products obtained by the desolventizing unit 6, the rectifying unit 14 is used for rectifying the bromide crude products to obtain bromide products, and the bromide product receiving tank 13 is used for storing high-purity bromide products obtained by rectifying the rectifying unit 14.
According to the invention, preferably, a condenser 10 is provided between the rectifying unit 14 and the bromide product receiving tank 13 for cooling the bromide product.
The invention also provides a method for continuously preparing 2, 6-diethyl-4-methyl bromobenzene, which is carried out by using the device disclosed by the invention, and the method comprises the following steps:
1) Continuously feeding the raw material A, the raw material B and the raw material C into the premixing unit 1 through the conveying unit 11 respectively for mixing and diazotizing;
2) Continuously feeding the diazotization reaction product into a storage unit 2 for further diazotization reaction;
3 continuously feeding the diazotization reaction product into the lower part of the inverse bromination unit 3, continuously feeding the raw material D into the upper part of the inverse bromination unit 3 through the conveying unit 31, and reversely contacting and brominating the raw material D with the diazotization reaction product;
4) Continuously feeding bromide solution from the upper part of the reverse bromination unit 3 to the lower part of the water washing unit 4, continuously feeding raw material E to the upper part of the water washing unit 4 by the conveying unit 51, and reversely washing the raw material E and bromide solution;
the raw material A is a toluene solution of 2, 6-diethyl-4-methylaniline, the raw material B is a hydrogen bromide aqueous solution, the raw material C is a sodium nitrite aqueous solution, the raw material D is a sodium bromide aqueous solution, and the raw material E is water.
According to the present invention, it is preferable that the aqueous phase at the bottom of the reverse bromination unit 3 is fed into the bromination waste water storage tank 5, and concentrated aqueous sodium bromide solution is fed into the upper part of the reverse bromination unit 3 as bromine source for bromination. Preferably, the concentration of sodium bromide in the concentrated aqueous sodium bromide solution is 8.5-11mol/L.
According to the method of the present invention, preferably, the toluene solution of 2, 6-diethyl-4-methylaniline has a concentration of 0.5 to 0.75mol/L; more preferably, the toluene solution of 2, 6-diethyl-4-methylaniline has a concentration of 0.6 to 0.65mol/L.
According to the method of the present invention, preferably, the concentration of the aqueous hydrogen bromide solution is 7.5 to 10mol/L; more preferably, the concentration of the aqueous hydrogen bromide is 8.5 to 8.6mol/L.
According to the method of the present invention, preferably, the concentration of the sodium nitrite aqueous solution is 5.5 to 8mol/L; the concentration of the sodium nitrite aqueous solution is 6.5-7mol/L.
According to the method of the present invention, preferably, the concentration of the aqueous sodium bromide solution is 8.5 to 11mol/L; more preferably, the concentration of the aqueous sodium bromide solution is 9.5 to 9.6mol/L.
According to the process of the present invention, preferably, the feed rates of the raw material a, the raw material B and the raw material C are such that the molar ratio of 2, 6-diethyl-4-methylaniline, hydrogen bromide and sodium nitrite is 1:2-4:1.05-1.25; more preferably, the feed rates of the raw material a, the raw material B and the raw material C are such that the molar ratio of 2, 6-diethyl-4-methylaniline, hydrogen bromide and sodium nitrite is 1:2.5-3.5:1.10-1.15.
According to the method of the invention, in step 1), the temperature of the mixing is between-20 and-5 ℃, preferably between-18 and-8 ℃.
According to the process of the present invention, in step 2), the diazotisation reaction is further carried out at a temperature of-18 to-10 ℃, preferably-10 to-5 ℃.
According to the process of the present invention, preferably, the feed D is fed to the reverse bromination unit 3 at a rate such that the molar ratio of diazotisation reaction product to sodium bromide, calculated on a theoretical basis, is 1:6.5 to 7.9; more preferably, the feed D is fed to the reverse bromination unit 3 at a rate such that the molar ratio of diazotisation reaction product to sodium bromide, calculated on a theoretical basis, is 1:6.8-7.2.
According to the process of the invention, preferably, the temperature of the countercurrent contact is from 40 to 85 ℃, and the time of countercurrent contact (i.e. residence time) is from 0.8 to 3.0 hours; more preferably, the temperature of the countercurrent contact is 50-60 ℃, and the time of the countercurrent contact is 1.0-1.5 hours.
According to the method of the present invention, the water washing is preferably carried out at a temperature of 40-80 ℃, preferably 40-60 ℃.
According to the method of the invention, in the washing unit 4, water is used in an amount of 1-5 times by weight of the theoretical amount of bromide; preferably, the amount of water is 1-2 times by weight the theoretical amount of bromide.
According to the method of the present invention, the method further comprises subjecting the bromide after washing with water to solvent removal in a desolventizing unit 6. The method for removing the solvent is not particularly limited, and distillation may be used, for example.
In a preferred scheme of the invention, the bromide after water washing is distilled to obtain a crude product of 2, 6-diethyl-4-methyl bromobenzene, and then the crude product is rectified to obtain the 2, 6-diethyl-4-methyl bromobenzene.
The distillation conditions may be appropriately selected by those skilled in the art depending on the equipment used and the desired product to be obtained, and for example, when a wiped evaporator is used, the wiped evaporator distillation conditions may be as follows: negative pressure 0.085MPa, feeding speed 405L/h, preheater temperature: 90 ℃, the discharge temperature on the scraper: desolventizing (toluene) at 60-90 ℃; the temperature of the lower discharge hole is controlled to be 90-110 ℃.
The conditions for the rectification preferably include: the temperature is 90-110 ℃, the pressure is 10-40apa, and the reflux ratio is as follows: 5-3:1.
The present invention will be described in detail by way of examples, but the present invention is not limited to the following examples.
The following examples were carried out using the apparatus of fig. 1. As shown in fig. 1, the apparatus includes: a premixing unit 1, a storage unit 2, a reverse bromination unit 3, a water washing unit 4, a bromination waste water storage tank 5, a desolventizing unit 6 and a conveying unit. Wherein, one end of the premixing unit 1 is connected with three conveying units 11, and the other end of the premixing unit 1 is connected with the storage unit 2; the bottom of the storage unit 2 is connected with the bottom of the inverse bromination unit 3 through a conveying unit 21; the top of the reverse bromination unit 3 is connected with a conveying unit 31, the upper part of the reverse bromination unit 3 is connected to the bottom of the washing unit through a conveying unit 32, and the lower part of the reverse bromination unit 3 is connected with the bromination waste water receiving tank; a conveying unit 51 is arranged between the water storage tank 7 and the washing unit 4; the upper part of the water washing unit 4 is connected with the desolventizing unit 6.
The pre-mixing unit 1 is a parallel tube reactor with a freezing jacket, the storage unit 2 is a stirring enamel kettle with a cooling jacket, the reverse bromination unit 3 is a paddle rotary bromination tower with a hot water jacket, the water washing unit 4 is a paddle rotary extraction tower, the bromination waste water storage tank 5 is an enamel receiving tank, the desolventizing unit 6 is a scraper evaporator, and the conveying unit is a double-plunger metering pump.
Example 1
1) Continuously feeding the raw material A, the raw material B and the raw material C into the premixing unit 1 through the conveying unit 11 respectively for mixing and diazotizing;
2) The diazotization reaction product is sent into a storage unit 2 for further diazotization reaction, the materials are free of crystal particles, and the materials are sampled and analyzed (derivatization method) to confirm that the diazotization reaction is complete;
3) Feeding the diazotization reaction product into the lower part of the inverse bromination unit 3, and feeding the raw material D into the upper part of the inverse bromination unit 3 through the conveying unit 31, so that the raw material D and the diazotization reaction product are in inverse contact and brominated;
4) Feeding bromide (2, 6-diethyl-4-methyl bromobenzene solution crude product) into the water washing unit 4 from the upper part of the reverse bromination unit 3 for water washing, feeding new process water (or washing water produced by neutralization desalination distillation) into the water washing unit 4 through a conveying unit 51 between the upper part of the water washing unit 4 and a water storage tank 7 for water washing, adjusting the liquid level height of a pi-shaped pipe between the water washing unit 4 and a washing wastewater storage tank, discharging the washing water from the lower part of the water washing unit 4 into a washing wastewater receiving tank 8, treating the wastewater in the washing wastewater receiving tank 8 by a neutralization and concentration desalination treatment device 17, and returning the produced neutral water into the water washing unit 4 as washing water E; feeding a hydrogen bromide/sodium bromide aqueous solution into the bromination waste water storage tank 5 from the lower part of the reverse bromination unit 3, concentrating the waste water in the bromination waste water storage tank 5 by a bromination waste water concentrating device 16, and feeding the concentrated waste water into the top of the reverse bromination unit 3 through a conveying unit 31 to be used as a bromine source;
5) The bromide (organic phase) after water washing is distilled in the desolventizing unit 6 to obtain a bromide crude product, which is stored in the bromide crude product receiving tank 12, and the bromide crude product stored in the bromide crude product receiving tank 12 is sent to a rectifying unit 14 (rectifying tower) for rectification to obtain 2, 6-diethyl-4-methyl bromobenzene, which is stored in the product receiving tank 13.
In the step 1), the raw material A is a toluene solution (molar concentration: 0.631 mol/L) of 2, 6-diethyl-4-methylaniline, the raw material B is an aqueous solution (molar concentration: 8.587 mol/L) of hydrogen bromide, the raw material C is an aqueous solution (molar concentration: 6.979 mol/L) of sodium nitrite, and the raw material D is an aqueous solution (molar concentration: 9.653 mol/L) of sodium bromide; the feed rate of the raw material A is 453.03L/h, the feed rate of the raw material B is 99.87L/h, and the feed rate of the raw material C is 46.10L/h, so that the molar ratio of 2, 6-diethyl-4-methylaniline, hydrogen bromide and sodium nitrite is 1:3:1.15; in addition, the temperature of the mixing was-10℃and the mixing time was 60min.
In step 2), the diazotisation reaction is further carried out at a temperature of-10 ℃.
In step 3), the feed rate of the raw material D is 212.98L/h, and the feed rate of the diazotization reaction product is 600L/h, so that the molar ratio of the diazotization reaction product to sodium bromide based on the theoretical amount is 1:7.2; and the temperature of the reverse contact is 50 ℃, the time of the reverse contact is 1 hour, the brominated wastewater extraction speed is controlled to be 405.01L/h, and the overhead organic phase extraction speed is controlled to be 407.96L/h.
The temperature of the water wash in step 4) is 40 ℃, and the feed rate of the raw material E is 129.87L/h so that the water consumption is 2.0 weight times of the theoretical amount of bromide; in addition, the feed rate under the water scrubber was 407.96L/h.
In step 5), wiped evaporator distillation conditions: negative pressure 0.085MPa, feeding speed 405L/h, preheater temperature: 90 ℃, the discharge temperature on the scraper: desolventizing at 60-90 deg.c and controlling the temperature at 90-110 deg.c in the lower discharging port
In step 6), batch distillation conditions: the collection reflux ratio was 5:1, negative pressure 40Pa, temperature: a fraction at 85 ℃, having a GC analysis content of 99.3 wt%; the yield thereof was found to be 92%; 92.1 wt% of the front-end fraction, which can be recycled to the rectification column.
Example 2
The procedure of example 1 was followed, except that the conditions of steps 1) to 5) were as follows.
In the step 1), the raw material A is a toluene solution (molar concentration: 0.7382 mol/L) of 2, 6-diethyl-4-methylaniline, the raw material B is an aqueous solution (molar concentration: 8.602 mol/L) of hydrogen bromide, the raw material C is an aqueous solution (molar concentration: 7.984 mol/L) of sodium nitrite, and the raw material D is an aqueous solution (molar concentration: 9.664 mol/L) of sodium bromide; the feed rate of the raw material A is 549.94L/h, the feed rate of the raw material B is 141.58L/h, and the feed rate of the raw material C is 58.473L/h, so that the molar ratio of 2, 6-diethyl-4-methylaniline, hydrogen bromide and sodium nitrite is 1:3.00:1.15; in addition, the temperature of the mixing was-10℃and the mixing time was 48min.
In step 2), the diazotisation reaction is further carried out at a temperature of-10 ℃.
In the step 3), the feeding speed of the raw material D is 302.46L/h, the feeding speed of the diazotization reaction product is 750L/h, so that the molar ratio of the diazotization reaction product to sodium bromide based on the theoretical amount is 1:7.2; and the temperature of the reverse contact is 60 ℃, the time of the reverse contact is 0.8 hour, the brominated wastewater extraction speed is controlled to be 473.08L/h, and the overhead organic phase extraction speed is controlled to be 579.38L/h.
The temperature of the water wash in step 4) is 40 ℃, and the feed rate of the raw material E is 184.43L/h so that the water consumption is 2.0 weight times of the theoretical amount of bromide; in addition, the feed rate under the water scrubber was 579.38L/h.
In step 5), conditions of wiped distillation desolventizing: negative pressure 0.085MPa, feeding speed 579.38L/h, preheater temperature: 90 ℃, the discharge temperature on the scraper: desolventizing at 60-90 deg.c and controlling the temperature at 90-110 deg.c in the lower discharging port
In step 6), batch distillation conditions: collecting negative pressure of 40Pa, and temperature: a fraction at 90-120 ℃; rectification conditions: the collection reflux ratio is: 6-1:1, negative pressure 30Pa, temperature: a fraction at 82-85 ℃, having a GC analysis content of 98.96 wt.%; yield 91.86%; 92.71 wt% of the front-end fraction can be recycled to the rectification column.
Example 3
The procedure of example 1 was followed, except that the conditions of steps 1) to 5) were as follows.
In the step 1), the raw material A is a toluene solution (molar concentration: 0.5235 mol/L) of 2, 6-diethyl-4-methylaniline, the raw material B is an aqueous solution (molar concentration: 7.571 mol/L) of hydrogen bromide, the raw material C is an aqueous solution (molar concentration: 5.9734 mol/L) of sodium nitrite, and the raw material D is an aqueous solution (molar concentration: 8.641 mol/L) of sodium bromide; the feed rate of the raw material A is 458.64L/h, the feed rate of the raw material B is 95.14L/h, and the feed rate of the raw material C is 46.22L/h, so that the molar ratio of 2, 6-diethyl-4-methylaniline, hydrogen bromide and sodium nitrite is 1:3:1.15; in addition, the temperature of the mixing was-15℃and the mixing time was 60min.
In step 2), the diazotisation reaction is further carried out at a temperature of-10 ℃.
In the step 3), the feeding speed of the raw material D is 200.06L/h, and the feeding speed of the diazotization reaction product is 600L/h, so that the molar ratio of the diazotization reaction product to sodium bromide based on the theoretical amount is 1;7.2; and the temperature of the reverse contact is 60 ℃, the time of the reverse contact is 1 hour, the brominated wastewater extraction speed is controlled to be 457.4L/h, and the overhead organic phase extraction speed is controlled to be 342.65L/h.
The temperature of the water washing in the step 4) is 25 ℃, the feeding speed of the raw material E is 109.18L/h, and the water consumption is 2.0 weight times of the theoretical amount of the bromide; in addition, the feeding speed under the water washing tower is 342.65L/h;
In step 5), conditions of wiped distillation desolventizing: negative pressure 0.085MPa, feeding speed 579.38L/h, preheater temperature: 90 ℃, the discharge temperature on the scraper: desolventizing at 60-90 deg.c and controlling the temperature at 90-110 deg.c in the lower discharging port
In step 6), batch distillation conditions: the collection reflux ratio is: 4-5:1, negative pressure 30Pa, temperature: fractions at 80 ℃, GC analysis content 98.75 wt%; the yield was 90.75%; 91.85% by weight of the front-end fraction, and can be recycled to the rectification column.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (33)
1. An apparatus for sandmeyer reaction, comprising:
a premixing unit (1) for mixing the reaction raw materials and performing diazotization reaction;
a storage unit (2) connected to the pre-mixing unit (1) for storing diazotization reaction products;
A reverse bromination unit (3) the lower part of which is connected with the storage unit (2), and the upper part of which is connected with a conveying unit (31) for conveying bromine source aqueous solution into the storage unit, and the reverse bromination unit is used for reversely contacting and brominating diazotization reaction products with the bromine source aqueous solution;
A water washing unit (4) with the lower part connected with the upper part of the reverse bromination unit (3), the upper part connected with a conveying unit (51) for conveying washing water into the water washing unit for washing bromide,
Wherein the premixing unit (1) is a parallel tube type reactor or a spiral tube type reactor, the reverse bromination unit (3) is a blade type rotary bromination tower, the water washing unit (4) is a water washing tower, a blade type rotary extraction tower or a centrifugal extraction machine,
The storage units (2) are storage tanks with cooling jackets, and the number of the storage units (2) is multiple.
2. The apparatus according to claim 1, wherein the pre-mixing unit (1) has a plurality of conveying units (11) for feeding raw materials into the pre-mixing unit (1) for a mixing reaction.
3. The apparatus according to claim 2, wherein the pre-mix unit (1) has 3 feed units.
4. The device according to claim 2, wherein the delivery unit (11) is a double plunger metering pump or a double diaphragm metering pump.
5. The device according to claim 1, wherein the delivery unit (31) is a double plunger metering pump or a double diaphragm metering pump.
6. The apparatus according to claim 1, wherein the pre-mixing unit (1) has a cooling unit for cooling the reaction mass.
7. The apparatus of claim 1, wherein the cooling unit is a cooling jacket.
8. The device according to claim 1, wherein the storage unit (2) has a stirring unit (22).
9. The device according to claim 1, wherein the number of storage units (2) is 2-3.
10. The apparatus according to claim 1, wherein a feed unit (21) is arranged between the storage unit (2) and the reverse bromination unit (3) for feeding diazotisation reaction products into the reverse bromination unit (3).
11. The device according to claim 10, wherein the feeding unit (21) is a double plunger metering pump or a double diaphragm metering pump.
12. The device according to claim 1, wherein the bottom of the reverse bromination unit (3) is connected with a bromination waste water storage tank (5) for temporary storage treatment of the water phase at the bottom of the reverse bromination unit (3).
13. The apparatus according to claim 12, wherein a pi-shaped pipe (33) is provided between the reverse bromination unit (3) and the bromination waste water storage tank (5), connects the bottom of the reverse bromination unit (3) and the bromination waste water storage tank (5), and is used for controlling the liquid level in the reverse bromination unit (3).
14. The apparatus according to claim 13, wherein the waste water in the bromination waste water storage tank (5) is concentrated by a concentrating device (16), and returned to the reverse bromination unit (3) via the conveying unit (31) to be used as a bromination raw material.
15. The device according to any one of claims 1-7, wherein a transport unit (51) is arranged between the water storage tank (7) and the water wash unit (4) for feeding water into the upper part of the water wash unit (4) for washing bromide solution from the upper part of the counter bromination unit (3).
16. The device according to claim 15, wherein the delivery unit (51) is a double plunger metering pump or a double diaphragm metering pump.
17. The device according to claim 16, wherein a conveying unit (32) is arranged between the counter-bromination unit (3) and the water washing unit (4) for feeding bromide solution to the bottom of the water washing unit (4) and performing counter-washing.
18. The device according to claim 17, wherein a washing wastewater receiving tank (8) is connected to the bottom of the washing unit (4) for temporary storage of the water phase at the bottom of the washing unit (4).
19. The device according to claim 18, wherein a pi-shaped pipe (41) is arranged between the washing unit (4) and the washing wastewater receiving tank (8), connects the bottom of the washing unit (4) and the washing wastewater receiving tank (8), and is used for controlling the liquid level in the washing unit (4).
20. The apparatus according to claim 15, wherein the apparatus further has a desolventizing unit (6) with a feed inlet connected to a top discharge of the washing unit (4) via a preheating unit (9) for desolventizing the washing product.
21. The apparatus of claim 20, wherein the desolvation unit (6) is one or more of a wiped film evaporator, a falling film evaporator and a rising film evaporator.
22. The apparatus according to claim 21, wherein the desolventizing unit (6) is a wiped film evaporator.
23. The apparatus of claim 21, wherein the desolventizing unit (6) is connected in sequence to a bromide crude receiving tank (12), a rectifying unit (14) and a bromide product receiving tank (13).
24. A process for the continuous preparation of 2, 6-diethyl-4-methyl bromobenzene, characterized in that it is carried out using an apparatus according to any one of claims 1 to 23, which comprises:
1) Continuously feeding the raw material A, the raw material B and the raw material C into a premixing unit (1) through a conveying unit (11) respectively for mixing and diazotizing;
2) Continuously feeding the diazotization reaction product into a storage unit (2) for further diazotization reaction;
3) Continuously feeding the diazotization reaction product into the lower part of a reverse bromination unit (3), continuously feeding a raw material D into the upper part of the reverse bromination unit (3) through a conveying unit (31), and reversely contacting and brominating the raw material D with the diazotization reaction product;
4) Continuously feeding bromide solution from the upper part of the reverse bromination unit (3) to the lower part of the water washing unit (4), continuously feeding raw material E to the upper part of the water washing unit (4) through a conveying unit (51), and reversely washing the raw material E and the bromide solution;
Wherein the raw material A is toluene solution of 2, 6-diethyl-4-methylaniline, the raw material B is hydrogen bromide water solution, the raw material C is sodium nitrite water solution, the raw material D is sodium bromide water solution, the raw material E is water,
In the step 1), the mixing temperature is-20 to-5 ℃,
In the step 2), the diazotization reaction is further carried out at a temperature of-10 to-5 ℃.
25. The method of claim 24, wherein the toluene solution of 2, 6-diethyl-4-methylaniline has a concentration of 0.5-0.75mol/L.
26. The method of claim 24, wherein the aqueous hydrogen bromide has a concentration of 7.5-10mol/L.
27. The method of claim 24, wherein the concentration of the aqueous sodium nitrite solution is 5.5-8mol/L.
28. The method of claim 24, wherein the aqueous sodium bromide has a concentration of 8.5-11mol/L.
29. The method of claim 24, wherein the feed rates of feed a, feed B, and feed C are such that the molar ratio of 2, 6-diethyl-4-methylaniline, hydrogen bromide, and sodium nitrite is 1:2-4:1.05-1.25.
30. A process according to any one of claims 24 to 29, wherein the feed D is fed to the reverse bromination unit (3) at a rate such that the molar ratio of diazotisation reaction product to sodium bromide on a theoretical basis is 1:6.5-7.9.
31. A process according to claim 30, wherein the aqueous bottom phase of the reverse bromination unit (3) is fed into a bromination waste water storage tank (5) and into a concentrating treatment device (16) for concentrating treatment, and the concentrated aqueous sodium bromide solution is fed into the upper part of the reverse bromination unit (3) as bromine source for bromination.
32. The method of claim 30, wherein the concentration of sodium bromide in the concentrated aqueous sodium bromide solution is 8.5-11mol/L.
33. A process according to claim 30, wherein the process further comprises removing solvent from the washed bromide in a desolventizing unit (6).
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| 梁世懿编.高等有机化学 结构反应合成.高等教育出版社,1993,239-240. * |
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