CN113754512B - Preparation method of o-bromobenzotrifluoride - Google Patents
Preparation method of o-bromobenzotrifluoride Download PDFInfo
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- CN113754512B CN113754512B CN202111013678.XA CN202111013678A CN113754512B CN 113754512 B CN113754512 B CN 113754512B CN 202111013678 A CN202111013678 A CN 202111013678A CN 113754512 B CN113754512 B CN 113754512B
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- bromobenzotrifluoride
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- RWXUNIMBRXGNEP-UHFFFAOYSA-N 1-bromo-2-(trifluoromethyl)benzene Chemical compound FC(F)(F)C1=CC=CC=C1Br RWXUNIMBRXGNEP-UHFFFAOYSA-N 0.000 title claims abstract description 56
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000000243 solution Substances 0.000 claims abstract description 98
- BMYNFMYTOJXKLE-UHFFFAOYSA-N 3-azaniumyl-2-hydroxypropanoate Chemical compound NCC(O)C(O)=O BMYNFMYTOJXKLE-UHFFFAOYSA-N 0.000 claims abstract description 94
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 claims abstract description 74
- 238000006243 chemical reaction Methods 0.000 claims abstract description 72
- VBLXCTYLWZJBKA-UHFFFAOYSA-N 2-(trifluoromethyl)aniline Chemical compound NC1=CC=CC=C1C(F)(F)F VBLXCTYLWZJBKA-UHFFFAOYSA-N 0.000 claims abstract description 63
- CPELXLSAUQHCOX-UHFFFAOYSA-N Hydrogen bromide Chemical compound Br CPELXLSAUQHCOX-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 37
- 235000010288 sodium nitrite Nutrition 0.000 claims abstract description 37
- 238000002156 mixing Methods 0.000 claims abstract description 32
- 229910021589 Copper(I) bromide Inorganic materials 0.000 claims abstract description 31
- NKNDPYCGAZPOFS-UHFFFAOYSA-M copper(i) bromide Chemical compound Br[Cu] NKNDPYCGAZPOFS-UHFFFAOYSA-M 0.000 claims abstract description 31
- 229910000042 hydrogen bromide Inorganic materials 0.000 claims abstract description 21
- 239000012954 diazonium Substances 0.000 claims abstract description 13
- 150000001989 diazonium salts Chemical class 0.000 claims abstract description 13
- 239000011259 mixed solution Substances 0.000 claims description 18
- 230000003068 static effect Effects 0.000 claims description 13
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 12
- 239000007788 liquid Substances 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 238000005406 washing Methods 0.000 claims description 10
- 239000002904 solvent Substances 0.000 claims description 9
- 238000000926 separation method Methods 0.000 claims description 8
- 239000012295 chemical reaction liquid Substances 0.000 claims description 5
- 239000003513 alkali Substances 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 4
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 2
- 239000008096 xylene Substances 0.000 claims description 2
- 238000005893 bromination reaction Methods 0.000 abstract description 8
- 238000006193 diazotization reaction Methods 0.000 abstract description 8
- 230000031709 bromination Effects 0.000 abstract description 2
- 238000004519 manufacturing process Methods 0.000 description 11
- 238000005516 engineering process Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000010923 batch production Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 239000012043 crude product Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 238000005755 formation reaction Methods 0.000 description 2
- 238000010606 normalization Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000010812 external standard method Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000002309 gasification Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- SLFVYFOEHHLHDW-UHFFFAOYSA-N n-(trifluoromethyl)aniline Chemical compound FC(F)(F)NC1=CC=CC=C1 SLFVYFOEHHLHDW-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 239000012450 pharmaceutical intermediate Substances 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000011343 solid material Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 239000007966 viscous suspension Substances 0.000 description 1
Classifications
-
- 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
-
- 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
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a preparation method of o-bromobenzotrifluoride, which comprises the following steps: sequentially introducing first hydrobromic acid, sodium nitrite solution and reaction solution A into a continuous flow reactor to carry out a mixing reaction to obtain diazonium salt solution; the reaction solution A is obtained by mixing and reacting second hydrobromic acid with o-trifluoromethyl aniline solution; the mass percentage of the hydrogen bromide in the second hydrobromic acid is 20-40%; the molar ratio of the hydrogen bromide in the second hydrobromic acid to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is (4-15): 1; mixing the diazonium salt solution with cuprous bromide and third hydrobromic acid for reaction. The invention adopts a continuous flow diazotization and intermittent bromination series process, and the diazotization and bromination reaction is continuously carried out by optimizing reaction parameters, and the reaction yield is not lower than the existing intermittent process level.
Description
Technical Field
The invention relates to a preparation method of o-bromobenzotrifluoride.
Background
O-bromobenzotrifluoride, also known as 2-bromobenzotrifluoride, is a water-white or pale yellow liquid, and is an important pesticide and pharmaceutical intermediate. As its use continues to expand, so does the market demand.
The o-trifluoromethylaniline is a byproduct of a trifluoromethylaniline production line, the purity of the o-trifluoromethylaniline reaches 99.5%, but the o-trifluoromethylaniline has small application range, small market demand and low price. By using o-trifluoromethylaniline as a raw material, o-bromobenzotrifluoride with more commercial value can be prepared.
At present, the production of the o-bromobenzotrifluoride is mainly carried out in an intermittent reaction kettle, but the batch process has long feeding and discharging time, the reaction time is of an hour level, and the production efficiency is low. In addition, the production of o-bromobenzotrifluoride can be subjected to diazotization technology, the technology belongs to dangerous chemical technology under national key supervision, when the technology is carried out in an intermittent reaction kettle, the volume of a reactor is generally larger, the temperature control accuracy is low, the material proportioning accuracy is low, the diazotization reaction is severe, the heat release amount is large, the problem of easy explosion exists, and a large amount of toxic and explosive gas can be generated sometimes, so that fire disaster is caused, and the safety risk is high.
In order to overcome the above-mentioned drawbacks of batch reactors in the production of ortho-bromobenzotrifluoride, the use of continuous flow reactors is contemplated. However, for continuous flow reactors, it is necessary that the reaction materials are all fluid and solids are not allowed to be produced, otherwise the equipment is blocked and the reaction cannot be performed normally. In fact, salt precipitation easily occurs in the production process of o-bromobenzotrifluoride, which hinders the application of the continuous flow reactor in the reaction system.
It is therefore of great importance to develop a preparation process which allows the production of o-bromobenzotrifluoride to proceed normally in a continuous flow reactor.
Disclosure of Invention
The invention aims to solve the technical problems that in the prior art, intermittent kettle type reaction is generally adopted for preparing o-bromotrifluoro toluene, and the risks of severe diazotization, explosiveness and the like exist, and provides a method for continuously producing the o-bromotrifluoro toluene.
In the research process, the applicant of the invention finds that if the kettle reaction of the o-bromobenzotrifluoride is simply adjusted to be continuous flow reaction, salt precipitation is easy to generate in the continuous flow reaction process, and the continuous flow reactor is blocked, so that the production cannot be normally performed in the continuous flow reactor.
Through a large number of experiments, the inventor creatively adopts a continuous flow diazotization and intermittent bromination series connection process, and through optimizing the raw material proportion, the salifying reaction temperature, the feeding sequence and the reaction conditions, the salifying and diazotizing reactions are continuously carried out, thereby breaking through the concept that solid materials cannot carry out continuous flow reaction, and ensuring that the reaction yield is not lower than the existing intermittent process level.
The invention solves the technical problems by the following technical scheme:
The preparation method of the o-bromobenzotrifluoride comprises the following steps:
(1) Sequentially introducing first hydrobromic acid, sodium nitrite solution and reaction solution A into a continuous flow reactor to carry out a mixing reaction to obtain diazonium salt solution;
The reaction solution A is obtained by mixing and reacting second hydrobromic acid with o-trifluoromethyl aniline solution; the temperature of the mixing reaction of the second hydrobromic acid and the o-trifluoromethyl aniline solution is 25-35 ℃;
The mass percentage of hydrogen bromide in the second hydrobromic acid is 20-40%; the molar ratio of the hydrogen bromide in the second hydrobromic acid to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is (4-15): 1;
(2) Mixing the diazonium salt solution with cuprous bromide and third hydrobromic acid for reaction.
Generally, hydrobromic acid is easily salified by mixing with o-trifluoromethylaniline to form a viscous suspension, and cannot enter the continuous flow reactor, and the inventor of the invention surprisingly found that the blockage of the continuous flow reactor can be effectively avoided at 10-35 ℃ by setting the concentration of the second hydrobromic acid, the molar ratio of hydrogen bromide in the second hydrobromic acid to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution, the temperature at which the second hydrobromic acid is mixed and reacted with the o-trifluoromethylaniline solution and the feeding sequence.
In the present invention, preferably, in step (1), the second hydrobromic acid is introduced into the continuous flow reactor after passing through a heater.
In the present invention, preferably, in step (1), the o-trifluoromethylaniline solution is fed into the continuous flow reactor after passing through a heater.
In the present invention, preferably, in the step (1), the temperature of the second hydrobromic acid is 25 to 35 ℃.
In the present invention, preferably, in the step (1), the temperature of the o-trifluoromethylaniline solution is 25 to 35 ℃.
In the present invention, preferably, in step (1), the second hydrobromic acid passes through the heater and enters a static mixer and then enters the continuous flow reactor.
In the present invention, preferably, in step (1), the o-trifluoromethylaniline solution is passed through a heater and then enters a static mixer, and then enters the continuous flow reactor.
In the present invention, preferably, in the step (1), the mixing reaction of the second hydrobromic acid with the o-trifluoromethylaniline solution is performed in the static mixer.
Preferably, in step (1), the molar ratio of hydrogen bromide in the second hydrobromic acid to o-trifluoromethylaniline in the o-trifluoromethylaniline solution is 7.5:1.
Preferably, in the step (1), the molar ratio of the hydrogen bromide in the second hydrobromic acid to the sodium nitrite in the sodium nitrite solution to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is (4-15): (1-1.08): 1, more preferably 7.5:1.05:1.
Preferably, in step (1), the mass percentage and the flow rate of hydrogen bromide in the first hydrobromic acid and the second hydrobromic acid are the same.
Preferably, in step (1), the mass percentage of hydrogen bromide in the first hydrobromic acid and the second hydrobromic acid is 25%.
Preferably, in step (1), the flow rates of both the first hydrobromic acid and the second hydrobromic acid are 3400g/h to 7000g/h, for example 4796g/h.
Preferably, in step (1), the flow rate ratio of the first hydrobromic acid to the second hydrobromic acid to the sodium nitrite solution is (4.9-10.7): 1.
In the present invention, preferably, in the step (1), the solvent of the sodium nitrite solution is water.
Preferably, in the step (1), the mass percentage of the sodium nitrite in the sodium nitrite solution is 10-40%, more preferably 30%.
In the present invention, preferably, in the step (1), the solvent of the o-trifluoromethylaniline solution is toluene and/or xylene.
Preferably, the mass percentage of the o-trifluoromethyl aniline in the o-trifluoromethyl aniline solution is 30-60%, more preferably 44.4%.
Preferably, in step (1), the o-trifluoromethylaniline solution is fed at a rate of between 500 and 1000g/h, for example 700g/h.
In the present invention, in the step (1), the flow rate ratio of the o-trifluoromethylaniline solution to the sodium nitrite solution is preferably (1.7 to 2.3): 1.
In the present invention, preferably, in the step (1), when the first hydrobromic acid and the sodium nitrite solution generate a reddish brown gas, the reaction solution a is further introduced to perform a mixing reaction.
In the present invention, preferably, in step (1), the continuous flow reactor is one or more of a static mixer, a microchannel reactor or a tubular reactor, and more preferably, a microchannel reactor. Those skilled in the art will appreciate that a continuous reaction system can be formed by parallelizing one or more of the continuous flow reactors described above, depending on the scale of production.
In the present invention, preferably, in the step (1), the temperature of the mixing reaction of the sodium nitrite solution and the reaction liquid A is-10 to 10 ℃, more preferably-5 to 0 ℃.
In the present invention, it is preferable that in the step (1), the time for the mixing reaction of the sodium nitrite solution and the reaction liquid A is 1 to 30 seconds, for example, 6 seconds.
In the present invention, preferably, in the step (1), the pressure of the mixing reaction of the sodium nitrite solution and the reaction liquid A is 0.1 to 0.3MPa, for example, 0.15MPa; the pressure is known to those skilled in the art as gauge pressure.
In the present invention, preferably, in step (1), the preparation method of o-bromobenzotrifluoride further includes liquid separation treatment of the diazonium salt solution.
In the present invention, preferably, in step (1), the solvent of the first hydrobromic acid and the solvent of the second hydrobromic acid are both water.
The liquid separation treatment may be conventional in the art. The liquid separation treatment is used for removing the organic phase of the diazonium salt solution.
In the present invention, preferably, in the step (2), the cuprous bromide and the third hydrobromic acid are present in the form of a mixed solution.
Preferably, in step (2), when the cuprous bromide and the third hydrobromic acid are present in the form of a mixed solution, the solvent of the mixed solution of cuprous bromide and the third hydrobromic acid is water.
Preferably, in the step (2), the mass percentage of the cuprous bromide in the mixed solution of the cuprous bromide and the third hydrobromic acid is 5% -30%, and more preferably 16.7%.
In the invention, the concentration of the third hydrobromic acid can be any concentration, and preferably, the mass percentage of the hydrogen bromide in the third hydrobromic acid can be 0-48%; in the case of 0, the reaction yield and reaction rate are slightly lowered, but the improvement essence of the present invention is not affected. Preferably, in the step (2), the mixed solution of the cuprous bromide and the third hydrobromic acid has a mass percentage of hydrogen bromide of 40% -48%, more preferably 48%.
In the present invention, preferably, in the step (2), the temperature of the mixing reaction is 30 to 50 ℃, more preferably 40 ℃.
In the present invention, preferably, in the step (2), the pressure of the mixing reaction is from-20 kPa to 10kPa, more preferably from-10 kPa; the pressure is known to those skilled in the art as gauge pressure.
In the present invention, preferably, in the step (2), the molar ratio of the cuprous bromide to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is (0.1 to 1): 1, more preferably 0.21. The amount of cuprous bromide used affects the yield and purity of the o-bromobenzotrifluoride.
In the present invention, preferably, in the step (2), the mixing reaction is performed in a batch tank reactor.
In the present invention, preferably, in the step (2), the diazonium salt solution is introduced into the third hydrobromic acid and the cuprous bromide which are premixed.
The person skilled in the art knows that after the step (2), the product at the outlet of the kettle-type reactor is collected for detection, and the product is qualified.
In the invention, preferably, the preparation method of the o-bromobenzotrifluoride further comprises post-treatment operations of liquid separation, alkali washing, water washing, reduced pressure concentration and rectification in sequence.
The post-treatment operations of the separating liquid, the alkaline washing, the water washing, the reduced pressure concentration, and the rectification may be conventional in the art.
The third hydrobromic acid and the cuprous bromide can be recovered for recycling through the liquid separation, alkali washing, water washing and reduced pressure concentration post-treatment; and obtaining the o-bromobenzotrifluoride with high purity through the rectification operation.
On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.
The reagents and materials used in the present invention are commercially available.
The invention has the positive progress effects that:
(1) According to the invention, by setting reaction conditions such as the concentration of the second hydrobromic acid, the proportion of the second hydrobromic acid to the o-trifluoromethylaniline, the temperature of the mixed reaction of the second hydrobromic acid and the o-trifluoromethylaniline solution, the feeding sequence and the like, the blockage of a continuous flow reactor can be avoided, the normal operation of the o-bromobenzotrifluoride production in the continuous flow reactor can be realized, and the continuous operation of the reaction can be ensured.
(2) The invention can obtain the o-bromotrifluoro toluene with the purity of 99.8 percent, the yield is 91.78 percent, the purity of the o-bromotrifluoro toluene prepared by the prior batch process is 99 percent, the yield is 91 percent, and the yield and the purity of the invention are equivalent to the prior art.
(3) The invention can realize the accurate input of materials by adopting the continuous reaction technology, and further, can rapidly remove the reaction heat by utilizing the excellent mass transfer capability of the microreactor, has small liquid holding volume in unit time, and greatly reduces the hazard degree of diazotization reaction.
(4) The invention adopts a continuous reaction technology, can realize automation, avoids the consumption of batch process feeding and discharging time, further, the on-line reaction time of the microchannel reactor is of the second level, the reaction efficiency is greatly improved, and the number of operators is reduced.
Drawings
FIG. 1 is a schematic flow chart of the production process of the present invention;
reference numerals:
11 a first hydrobromic acid delivery pump, 12 a sodium nitrite solution delivery pump, 13 an o-trifluoromethyl aniline solution delivery pump, and 14 a second hydrobromic acid delivery pump; 21 a first heater, 22a second heater, 23 a third heater; 31 a first static mixer, 32 a second static mixer; a microchannel reactor; 5 batch reactor.
Detailed Description
The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.
In the following examples and comparative examples, the purity of o-bromobenzotrifluoride was determined by the GC external standard method. The method comprises the following steps: 1.0g of the sample was taken and fixed to a volume of 50ml with methanol, analyzed by GC, and the contents of the respective substances were quantified by an area normalization method. GC instrument model: agilent 7820A; chromatographic column model: DB-1701 (30 m.320 um.0.25 um); carrier gas high purity nitrogen (0.9999); a detector: a FID detector; flow rate hydrogen: 30ml/min; air: 300ml/min; nitrogen gas: 1.0ml/min; split ratio: 30:1, a step of; tail blow flow: 25ml/min; temperature column temperature: maintaining at 80deg.C for 2min, and raising the temperature to 260 deg.C at 30deg.C/min for 2min; gasification temperature: 250 ℃; detector temperature: 300 ℃; the calculation method is a peak area normalization method.
Example 1
In combination with the process of fig. 1 as described above, a mixed solution of cuprous bromide and third hydrobromic acid is prepared in a batch reactor 5, wherein the ratio of cuprous bromide to the mixed solution is 16.7% (wt), the ratio of hydrogen bromide to the mixed solution is 48% (wt), and the mixed solution is controlled to be at 40 ℃ for standby;
44.4% (wt) o-trifluoromethylaniline/toluene solution, 25% (wt) hydrobromic acid and 30% (wt) sodium nitrite solution were prepared separately in a compounding tank for use.
Starting a 25% (wt) first hydrobromic acid conveying pump 11, preheating to 35 ℃ through a first heater 21, and feeding the first hydrobromic acid to a micro-channel reactor 4 through a static mixer 31, wherein the temperature of the micro-channel reactor 4 is controlled to be between-5 and 0 ℃; after 25% (wt) of the first hydrobromic acid flows out of the micro-channel reactor 4, starting a 30% (wt) sodium nitrite solution delivery pump 12 to feed the micro-channel reactor 4, wherein the temperature of the micro-channel reactor 4 is controlled at-5-0 ℃; after reddish brown gas is generated at the outlet of the microchannel reactor 4, starting a 44.4% (wt) o-trifluoromethylaniline/toluene solution delivery pump 13, preheating to 35 ℃ by a second heater 22, then entering a static mixer 32 to carry out salt formation reaction with second hydrobromic acid which is delivered by a second hydrobromic acid delivery pump 14 and preheated by a third heater 23, wherein the temperature of the static mixer 32 is controlled to be 25-35 ℃ during the salt formation reaction, and the salified material enters the microchannel reactor 4 to carry out diazotization reaction, and the temperature of the microchannel reactor 4 is controlled to be-5-0 ℃.
In the actual operation process, the pipelines for operating the first hydrobromic acid and the second hydrobromic acid can be combined into one, namely two pipelines are combined into one.
After the system is stable, the outlet of the micro-channel reactor 4 is connected into a batch reaction kettle 5 where a mixed solution of cuprous bromide (16.7 wt%)/third hydrobromic acid (48 wt%) is located, the bromination reaction is carried out, and the temperature of the bromination reaction is controlled to be 40 ℃. Wherein the molar ratio of the cuprous bromide in the mixed solution of the cuprous bromide (16.7 wt%)/the third hydrobromic acid (48 wt%) to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is 0.21:1.
After the diazonium salt solution in the batch reactor 5 is connected with a specified amount, the outlet of the micro-channel reactor 4 can be connected with another batch reactor with the same loading, and the reaction is kept continuously.
Wherein the flow rate of the first hydrobromic acid and the second hydrobromic acid is 4796g/h; the flow rate of the sodium nitrite solution is 447g/h; the feeding flow rate of the o-trifluoromethyl aniline solution is 700g/h; the time of the mixing reaction of the sodium nitrite solution and the reaction solution A is 6s, and the pressure is 0.15MPa; the pressure of the bromination reaction was-10 kPa.
Bromination reaction is carried out in the intermittent reaction kettle 5 which is connected with the diazonium salt with the specified quantity, and stirring and heat preservation are continuously carried out until the central control detection is qualified.
The bromination reaction liquid is subjected to liquid separation, alkali washing, water washing and reduced pressure concentration to obtain a crude product, and the third hydrobromic acid and cuprous bromide are recovered for recycling.
And rectifying the crude product to obtain the final product 2-bromobenzotrifluoride, namely the o-bromobenzotrifluoride.
Examples 2 to 5 and comparative examples 1 to 3
The results are shown in Table 1 below, except for the data shown in Table 1 below.
TABLE 1
Claims (15)
1. The preparation method of the o-bromobenzotrifluoride is characterized by comprising the following steps:
(1) Sequentially introducing first hydrobromic acid, sodium nitrite solution and reaction solution A into a continuous flow reactor to carry out a mixing reaction to obtain diazonium salt solution;
The reaction solution A is obtained by mixing and reacting second hydrobromic acid with o-trifluoromethyl aniline solution; the temperature of the mixing reaction of the second hydrobromic acid and the o-trifluoromethyl aniline solution is 25-35 ℃;
The mass percentage of the hydrogen bromide in the second hydrobromic acid is 20-40%; the molar ratio of the hydrogen bromide in the second hydrobromic acid to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is (4-15): 1;
(2) Mixing the diazonium salt solution with cuprous bromide and third hydrobromic acid for reaction.
2. The method for preparing o-bromobenzotrifluoride according to claim 1, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
in step (1), the second hydrobromic acid passes through a heater and enters the continuous flow reactor;
In the step (1), the o-trifluoromethyl aniline solution enters the continuous flow reactor after passing through a heater;
In the step (1), the temperature of the second hydrobromic acid is 25-35 ℃;
in the step (1), the temperature of the o-trifluoromethyl aniline solution is 25-35 ℃.
3. The method for preparing o-bromobenzotrifluoride according to claim 1, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
In the step (1), the second hydrobromic acid enters a static mixer after passing through a heater and then enters the continuous flow reactor;
in the step (1), the o-trifluoromethyl aniline solution enters a static mixer after passing through a heater, and then enters the continuous flow reactor.
4. The method for preparing o-bromobenzotrifluoride as claimed in claim 3, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
In step (1), the mixing reaction of the second hydrobromic acid with the o-trifluoromethylaniline solution is performed in the static mixer.
5. The method for preparing o-bromobenzotrifluoride according to claim 1, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
In the step (1), the mass percentage and the flow rate of the hydrogen bromide in the first hydrobromic acid and the second hydrobromic acid are the same;
In step (1), the solvent of both the first hydrobromic acid and the second hydrobromic acid is water.
6. The method for preparing o-bromobenzotrifluoride as claimed in claim 5, wherein said method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
in the step (1), the mass percentage of the hydrogen bromide in the first hydrobromic acid and the second hydrobromic acid is 25%;
in step (1), the molar ratio of hydrogen bromide in the second hydrobromic acid to o-trifluoromethylaniline in the o-trifluoromethylaniline solution is 7.5:1, a step of;
in the step (1), the molar ratio of the hydrogen bromide in the second hydrobromic acid, the sodium nitrite in the sodium nitrite solution and the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is (4-15): (1-1.08): 1, a step of;
in the step (1), the flow rates of the first hydrobromic acid and the second hydrobromic acid are 3400 g/h-7000 g/h;
in the step (1), the flow rate ratio of the first hydrobromic acid to the second hydrobromic acid to the sodium nitrite solution is (4.9-10.7) 1.
7. The method for preparing o-bromobenzotrifluoride as claimed in claim 6, wherein said method for preparing o-bromobenzotrifluoride satisfies one or both of the following conditions:
In the step (1), the molar ratio of the hydrogen bromide in the second hydrobromic acid, the sodium nitrite in the sodium nitrite solution and the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is 7.5:1.05:1;
in step (1), the flow rates of both the first hydrobromic acid and the second hydrobromic acid are 4796g/h.
8. The method for preparing o-bromobenzotrifluoride according to claim 1, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
in the step (1), the solvent of the sodium nitrite solution is water;
In the step (1), the mass percentage of sodium nitrite in the sodium nitrite solution is 10-40%;
In the step (1), the solvent of the o-trifluoromethyl aniline solution is toluene and/or xylene;
In the step (1), the mass percentage of the o-trifluoromethyl aniline in the o-trifluoromethyl aniline solution is 30-60%;
in the step (1), the feeding flow rate of the o-trifluoromethyl aniline solution is 500-1000 g/h;
In the step (1), the flow rate ratio of the o-trifluoromethyl aniline solution to the sodium nitrite solution is (1.7-2.3): 1.
9. The method for preparing o-bromobenzotrifluoride as claimed in claim 8, wherein the method for preparing o-bromobenzotrifluoride satisfies one or both of the following conditions:
in the step (1), the mass percentage of sodium nitrite in the sodium nitrite solution is 30%;
in the step (1), the mass percentage of the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is 44.4%.
10. The method for preparing o-bromobenzotrifluoride according to claim 1, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
In the step (1), when the first hydrobromic acid and the sodium nitrite solution generate reddish brown gas, the reaction solution A is introduced;
in step (1), the continuous flow reactor is one or more of a static mixer, a microchannel reactor or a tubular reactor;
in the step (1), the temperature of the mixing reaction of the sodium nitrite solution and the reaction solution A is-10 ℃;
in the step (1), the time of the mixing reaction of the sodium nitrite solution and the reaction solution A is 1-30 s;
In the step (1), the pressure of the mixing reaction of the sodium nitrite solution and the reaction solution A is 0.1-0.3Mpa;
In the step (1), the preparation method of the o-bromobenzotrifluoride further comprises the step of carrying out liquid separation treatment on the diazonium salt solution.
11. The method for preparing o-bromobenzotrifluoride according to claim 1, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions: in step (1), the continuous flow reactor is a microchannel reactor;
In the step (1), the temperature of the mixing reaction of the sodium nitrite solution and the reaction solution A is-5-0 ℃;
In the step (1), the time of the mixing reaction of the sodium nitrite solution and the reaction solution A is 6s;
in the step (1), the pressure of the mixing reaction of the sodium nitrite solution and the reaction liquid A is 0.15MPa.
12. The method for preparing o-bromobenzotrifluoride according to claim 1, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
in step (2), the cuprous bromide and the third hydrobromic acid are present as a mixed solution;
in the step (2), the temperature of the mixing reaction is 30-50 ℃;
in the step (2), the pressure of the mixing reaction is-20 kPa-10 kPa;
In the step (2), the molar ratio of the cuprous bromide to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is (0.1-1): 1, a step of;
In step (2), the mixing reaction is performed in a batch kettle reactor;
In step (2), the diazonium salt solution is passed into the third hydrobromic acid and the cuprous bromide, which are premixed;
The preparation method of the o-bromobenzotrifluoride further sequentially comprises the post-treatment operations of liquid separation, alkali washing, water washing, reduced pressure concentration and rectification.
13. The method for preparing o-bromobenzotrifluoride as claimed in claim 12, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
In the step (2), the temperature of the mixing reaction is 40 ℃;
In the step (2), the pressure of the mixed reaction is-10 kPa;
in the step (2), the molar ratio of the cuprous bromide to the o-trifluoromethylaniline in the o-trifluoromethylaniline solution is 0.21.
14. The method for preparing o-bromobenzotrifluoride as claimed in claim 12, wherein the method for preparing o-bromobenzotrifluoride satisfies one or more of the following conditions:
When the cuprous bromide and the third hydrobromic acid exist in the form of a mixed solution, the solvent of the mixed solution of the cuprous bromide and the third hydrobromic acid is water;
in the mixed solution of the cuprous bromide and the third hydrobromic acid, the mass percentage of the cuprous bromide is 5% -30%;
and in the mixed solution of the cuprous bromide and the third hydrobromic acid, the mass percentage of the hydrogen bromide is 40-48%.
15. The method for preparing o-bromobenzotrifluoride as claimed in claim 12, wherein said method for preparing o-bromobenzotrifluoride satisfies one or both of the following conditions:
In the mixed solution of the cuprous bromide and the third hydrobromic acid, the mass percentage of the cuprous bromide is 16.7%;
And in the mixed solution of the cuprous bromide and the third hydrobromic acid, the mass percentage of the hydrogen bromide is 48%.
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