CN114835555A - Method for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization - Google Patents
Method for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization Download PDFInfo
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- LZDSILRDTDCIQT-UHFFFAOYSA-N dinitrogen trioxide Chemical compound [O-][N+](=O)N=O LZDSILRDTDCIQT-UHFFFAOYSA-N 0.000 title claims abstract description 66
- 238000006193 diazotization reaction Methods 0.000 title claims abstract description 31
- 238000000034 method Methods 0.000 title claims abstract description 24
- GBOWGKOVMBDPJF-UHFFFAOYSA-N 1-fluoro-3-(trifluoromethyl)benzene Chemical compound FC1=CC=CC(C(F)(F)F)=C1 GBOWGKOVMBDPJF-UHFFFAOYSA-N 0.000 title claims abstract description 17
- 239000002253 acid Substances 0.000 claims abstract description 56
- 239000012954 diazonium Substances 0.000 claims abstract description 55
- 150000001989 diazonium salts Chemical class 0.000 claims abstract description 55
- 238000006243 chemical reaction Methods 0.000 claims abstract description 38
- 238000005979 thermal decomposition reaction Methods 0.000 claims abstract description 38
- 239000007788 liquid Substances 0.000 claims abstract description 19
- 238000005086 pumping Methods 0.000 claims abstract description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000012452 mother liquor Substances 0.000 claims abstract description 14
- 238000005507 spraying Methods 0.000 claims abstract description 13
- VIUDTWATMPPKEL-UHFFFAOYSA-N 3-(trifluoromethyl)aniline Chemical compound NC1=CC=CC(C(F)(F)F)=C1 VIUDTWATMPPKEL-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000002351 wastewater Substances 0.000 claims abstract description 12
- 238000003860 storage Methods 0.000 claims abstract description 10
- 238000004065 wastewater treatment Methods 0.000 claims abstract description 9
- 238000001035 drying Methods 0.000 claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 claims abstract description 6
- 239000000243 solution Substances 0.000 claims description 63
- 150000003839 salts Chemical class 0.000 claims description 23
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 16
- 238000005119 centrifugation Methods 0.000 claims description 15
- 239000003463 adsorbent Substances 0.000 claims description 9
- RILZRCJGXSFXNE-UHFFFAOYSA-N 2-[4-(trifluoromethoxy)phenyl]ethanol Chemical compound OCCC1=CC=C(OC(F)(F)F)C=C1 RILZRCJGXSFXNE-UHFFFAOYSA-N 0.000 claims description 5
- 238000005755 formation reaction Methods 0.000 claims 1
- 239000002910 solid waste Substances 0.000 abstract description 7
- 239000002699 waste material Substances 0.000 abstract description 7
- 239000010808 liquid waste Substances 0.000 abstract 1
- 239000000047 product Substances 0.000 description 14
- 238000003682 fluorination reaction Methods 0.000 description 13
- 239000007789 gas Substances 0.000 description 11
- 239000003153 chemical reaction reagent Substances 0.000 description 10
- GETTZEONDQJALK-UHFFFAOYSA-N (trifluoromethyl)benzene Chemical compound FC(F)(F)C1=CC=CC=C1 GETTZEONDQJALK-UHFFFAOYSA-N 0.000 description 5
- VBLXCTYLWZJBKA-UHFFFAOYSA-N 2-(trifluoromethyl)aniline Chemical compound NC1=CC=CC=C1C(F)(F)F VBLXCTYLWZJBKA-UHFFFAOYSA-N 0.000 description 4
- WTEOIRVLGSZEPR-UHFFFAOYSA-N boron trifluoride Chemical compound FB(F)F WTEOIRVLGSZEPR-UHFFFAOYSA-N 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910015900 BF3 Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 239000012043 crude product Substances 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- JDPAUQKBDYMQJK-UHFFFAOYSA-N 1,2,3,4-tetrafluoro-5-methylbenzene Chemical compound CC1=CC(F)=C(F)C(F)=C1F JDPAUQKBDYMQJK-UHFFFAOYSA-N 0.000 description 1
- JRTYPYSADXRJBQ-UHFFFAOYSA-N 1-fluoro-3-(trichloromethyl)benzene Chemical compound FC1=CC=CC(C(Cl)(Cl)Cl)=C1 JRTYPYSADXRJBQ-UHFFFAOYSA-N 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 239000010413 mother solution Substances 0.000 description 1
- 238000006396 nitration reaction Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
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- 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
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
- C07C17/383—Separation; Purification; Stabilisation; Use of additives by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
-
- 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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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a method for preparing 3-fluorotrifluorotoluene based on diazotization of dinitrogen trioxide, which comprises the following steps: pumping a fluoboric acid solution and m-amino benzotrifluoride into a salt-forming microchannel reactor for reaction, introducing a product into a diazonium salt tubular reactor, introducing dinitrogen trioxide for reaction, introducing the product into a diazonium salt temporary storage kettle, then carrying out continuous centrifugal treatment, drying the diazonium salt and carrying out thermal decomposition treatment; concentrating the centrifuged mother liquor, and reusing the waste water obtained in the concentration process for preparing the fluoboric acid solution; gas generated in the thermal decomposition treatment of the diazonium salt is sprayed and absorbed by acid liquor, and residue generated in the thermal decomposition treatment is used for wastewater treatment; and (4) layering the liquid after spraying and absorbing, pumping the oil layer into a rectifying tower for rectifying treatment to obtain a target product, and using the water layer for preparing the fluoboric acid solution. The invention recycles the waste liquid and solid waste in the production, effectively saves resources, and has high product yield and high purity.
Description
Technical Field
The invention relates to the technical field of organic synthesis, in particular to a method for preparing 3-fluorotrifluorotoluene based on diazotization of dinitrogen trioxide.
Background
3-fluorotrifluorotoluene, also known as m-fluorotrifluorotoluene, is an intermediate product for producing o-trifluoromethylaniline, and is an important intermediate for synthesizing pesticides and medicines due to the high efficiency and low toxicity of o-trifluoromethylaniline. In recent years, with the continuous development of downstream products of o-trifluoromethylaniline, the demand of o-trifluoromethylaniline increases year by year,
at present, the industrial production method of 3-fluorotrifluorotoluene mainly takes trifluorotoluene as a raw material, and the trifluorotoluene is obtained by nitration, hydrogenation reduction and fluorination in sequence, the purity of the 3-trifluorotoluene prepared by the reactions is high, but the reaction route is long, the process is complex, the product cost is high, and the production process can cause serious pollution to the environment.
Disclosure of Invention
The invention aims to provide a method for preparing 3-fluorobenzotrifluoride based on diazotization of dinitrogen trioxide, which takes m-amino benzotrifluoride as a raw material and carries out fluorination, diazotization and thermal decomposition treatment in sequence, the waste liquid after filtration of diazotization solution is concentrated and reused, and waste residues and waste gases generated during thermal decomposition treatment are recycled, thereby effectively saving resources and having high product yield and high purity.
In order to achieve the purpose, the scheme provided by the invention is as follows:
a method for preparing 3-fluorotrifluorotoluene based on diazotization of dinitrogen trioxide comprises the following steps:
(1) pumping the fluoboric acid solution and m-amino benzotrifluoride into a salifying microchannel reactor at a certain flow rate for salifying reaction, and entering into a diazonium salt tubular reactor after salifying;
(2) introducing dinitrogen trioxide into a diazonium salt tubular reactor to carry out diazotization reaction, allowing the diazonium salt solution and the acid solution generated by the reaction to enter a diazonium salt temporary storage kettle, carrying out continuous centrifugation, drying the diazonium salt obtained by centrifugation, and carrying out thermal decomposition treatment; concentrating the mother liquor after centrifugal treatment, concentrating the feed liquid to the concentration of the fluoboric acid solution before feeding, and reusing the waste water obtained during concentration for preparing the fluoboric acid solution;
(3) gas generated in the thermal decomposition treatment of the diazonium salt is sprayed and absorbed by acid liquor, and residue generated in the thermal decomposition treatment is collected and used as an adsorbent for wastewater treatment; and (3) layering the liquid after spraying and absorbing, pumping the oil layer obtained by layering into a rectifying tower for rectifying treatment, collecting a target product, and using the water layer obtained by layering for preparing the fluoboric acid solution and reusing the solution in the reaction.
Preferably, in the step (1), the feed flow rates of the fluoroboric acid solution and the m-aminobenzotrifluoride solution are respectively 8-12g/min and 1.5-1.8 g/min.
Preferably, in the step (1), the fluoroboric acid solution has a mass concentration of 20 to 30%.
Preferably, in the step (1), the temperature of the salt forming reaction is 10-20 ℃.
Preferably, in the step (2), the flow rate of the dinitrogen trioxide is controlled to be 0.3 to 0.5 g/min.
Preferably, in the step (2), the temperature of the diazotization reaction is-2 to-10 ℃.
As the optimization of the technical proposal, in the step (2), the temperature of the thermal decomposition is 600-700 ℃, and the thermal decomposition rate is controlled to be 2-3 g/min.
Preferably, in the step (3), the acid solution is hydrofluoric acid.
The method comprises the steps of centrifuging heavy nitrogen liquid after diazotization is finished, concentrating the centrifuged mother liquor until the concentration of the fluoboric acid in the feed liquid is the same as that of the fluoboric acid solution before reaction, reusing the concentrated solution in the fluorination reaction, and using the wastewater generated in the concentration process to prepare the fluoboric acid solution.
When the diazonium salt is thermally decomposed, gas generated by thermal decomposition is sprayed by hydrofluoric acid solution, the sprayed liquid is layered, an oil layer is sent to a rectifying tower to be rectified to prepare a target product, and a water layer can be used for preparing fluoboric acid solution and reusing the fluoboric acid solution in fluorination reaction. Waste residues generated in the thermal decomposition process can be used as an adsorbent for wastewater treatment.
The method adopts the dinitrogen trioxide as the diazotization reagent, the pressure in the dinitrogen trioxide storage tank is less than or equal to 0.03MPa, and meanwhile, the temperature of the dinitrogen trioxide storage tank and the dinitrogen trioxide feeding pipeline is ensured to be minus 30 +/-3 ℃. When the dinitrogen trioxide is fed, the dinitrogen trioxide can enter the diazonium salt tubular reactor for diazotization reaction in a self-pressure mode only by opening a feeding valve of the dinitrogen trioxide, and the operation is convenient.
Compared with the prior art, the invention has the following beneficial effects:
the method takes m-amino benzotrifluoride as a raw material, firstly takes fluoroboric acid solution as a fluorination reagent to carry out fluorination reaction, and then takes dinitrogen trioxide as a diazotization reagent to carry out diazotization reaction. The dinitrogen trioxide is used as a diazotization reagent, does not generate a large amount of sodium-containing wastewater, and is beneficial to environmental protection.
After the diazonium salt solution prepared by the method is centrifuged, the mother solution obtained by centrifugation is diluted fluoboric acid solution, the diluted fluoboric acid solution is concentrated to the concentration of the fluoboric acid solution as a reaction raw material, and then the concentrated fluoboric acid solution is directly used in the fluorination reaction, and the wastewater generated in the concentration process is continuously used in the preparation of the fluoboric acid solution for recycling and saving energy.
The diazonium salt is dried and pyrolyzed continuously, gas obtained by pyrolysis is sprayed by using acid liquor, when the gas is sprayed, the acid liquor effectively absorbs waste boron trifluoride gas and mixes the waste boron trifluoride gas with a crude product of 3-fluorobenzotrifluoride, then layering treatment is carried out, the crude product of 3-fluorotrichlorotoluene obtained by layering is rectified to prepare a target product, and a layered water layer can be used for preparing a fluoroboric acid solution serving as a fluorination reagent, so that the energy is further saved, and the preparation cost of the product is effectively reduced. The tar generated in the thermal decomposition process is directly carbonized at high temperature, and the carbonized solid can be used as an adsorbent for directly treating wastewater, so that the cost is further reduced, the solid waste discharge is reduced, and the energy conservation and environmental protection are realized.
Drawings
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
In order that the invention may be better understood, the invention is further illustrated by the following examples, which are intended to be illustrative only and are not intended to be limiting.
Example 1
(1) Pumping a fluoboric acid solution with the mass concentration of 25% and m-amino benzotrifluoride into a salifying microchannel reactor at the flow rates of 9g/min and 1.5g/min respectively to carry out salifying reaction at 15 ℃, and entering the diazonium salt tubular reactor after salification;
(2) introducing dinitrogen trioxide into a diazonium salt tubular reactor at the flow rate of 0.35g/min, carrying out diazotization reaction at the temperature of-5 ℃, allowing a diazonium salt solution and an acid solution generated by the reaction to enter a diazonium salt temporary storage kettle, carrying out continuous centrifugation treatment, drying the diazonium salt obtained by centrifugation, carrying out thermal decomposition treatment on the dried diazonium salt at the temperature of 600 ℃, and controlling the thermal decomposition rate to be 2 g/min; concentrating the mother liquor after centrifugal treatment until the mass concentration of the fluoboric acid in the feed liquid is 25%, then using the concentrated mother liquor as a fluorination reagent for the salt-forming reaction in the step (1), and reusing the waste water obtained during concentration for preparing a fluoboric acid solution and using the solution in the salt-forming reaction in the step (1);
(3) spraying and absorbing gas generated in the thermal decomposition treatment of the diazonium salt in the step (2) by adopting hydrofluoric acid, layering the liquid after spraying and absorbing, pumping an oil layer obtained by layering into a rectifying tower for rectifying treatment, controlling the temperature at the top of the tower to be 80 ℃ and the temperature at the bottom of the tower to be 105 ℃ during rectifying treatment, collecting a target product, and using a water layer obtained by layering for preparing a fluoboric acid solution and reusing the water layer in the salt forming reaction in the step (1); solid waste generated in the thermal decomposition is used as an adsorbent for wastewater treatment.
Example 2
(1) Pumping a fluoboric acid solution with the mass concentration of 25% and m-amino benzotrifluoride into a salt forming microchannel reactor at the flow rates of 10g/min and 1.55g/min respectively to perform salt forming reaction at the temperature of 10 ℃, and entering into a diazonium salt tubular reactor after salt forming;
(2) introducing dinitrogen trioxide into a diazonium salt tubular reactor at the flow rate of 0.4g/min, carrying out diazotization reaction at the temperature of-5 ℃, allowing a diazonium salt solution and an acid solution generated by the reaction to enter a diazonium salt temporary storage kettle, carrying out continuous centrifugation treatment, drying the diazonium salt obtained by centrifugation, carrying out thermal decomposition treatment on the dried diazonium salt at the temperature of 700 ℃, and controlling the thermal decomposition rate to be 3 g/min; concentrating the mother liquor after centrifugal treatment until the mass concentration of the fluoboric acid is 25%, then using the concentrated mother liquor as a fluorination reagent in the salt forming reaction in the step (1), and reusing the waste water obtained during concentration in preparing the fluoboric acid solution and in the salt forming reaction in the step (1);
(3) spraying and absorbing gas generated in the thermal decomposition treatment of the diazonium salt in the step (2) by adopting hydrofluoric acid, layering the liquid after spraying and absorbing, pumping an oil layer obtained by layering into a rectifying tower for rectifying treatment, controlling the temperature at the top of the tower to be 80 ℃ and the temperature at the bottom of the tower to be 105 ℃ during rectifying treatment, collecting a target product, and using a water layer obtained by layering for preparing a fluoboric acid solution and reusing the water layer in the salt forming reaction in the step (1); solid waste generated in the thermal decomposition is used as an adsorbent for wastewater treatment.
Example 3
(1) Pumping a fluoboric acid solution with the mass concentration of 25% and m-amino benzotrifluoride into a salt forming microchannel reactor at the flow rates of 10g/min and 1.65g/min respectively to perform salt forming reaction at the temperature of 10 ℃, and entering into a diazonium salt tubular reactor after salt forming;
(2) introducing dinitrogen trioxide into a diazonium salt tubular reactor at the flow rate of 0.5g/min, carrying out diazotization reaction at the temperature of-5 ℃, allowing a diazonium salt solution and an acid solution generated by the reaction to enter a diazonium salt temporary storage kettle, carrying out continuous centrifugation treatment, drying the diazonium salt obtained by centrifugation, and carrying out thermal decomposition treatment on the dried diazonium salt at the temperature of 650 ℃, wherein the thermal decomposition rate is controlled to be 2-3 g/min; concentrating the mother liquor after centrifugal treatment until the mass concentration of the fluoboric acid in the feed liquid is 25%, then using the concentrated mother liquor as a fluorination reagent for the salt-forming reaction in the step (1), and reusing the waste water obtained during concentration for preparing a fluoboric acid solution and using the solution in the salt-forming reaction in the step (1);
(3) spraying and absorbing gas generated in the thermal decomposition treatment of the diazonium salt in the step (2) by adopting hydrofluoric acid, layering the liquid after spraying and absorbing, pumping an oil layer obtained by layering into a rectifying tower for rectifying treatment, controlling the temperature at the top of the tower to be 80 ℃ and the temperature at the bottom of the tower to be 105 ℃ during rectifying treatment, collecting a target product, and using a water layer obtained by layering for preparing a fluoboric acid solution and reusing the water layer in the salt forming reaction in the step (1); solid waste generated in the thermal decomposition is used as an adsorbent for wastewater treatment.
Example 4
(1) Pumping a fluoboric acid solution with the mass concentration of 25% and m-amino benzotrifluoride into a salt forming microchannel reactor at the flow rates of 11g/min and 1.7g/min respectively to perform salt forming reaction at the temperature of 10 ℃, and entering into a diazonium salt tubular reactor after salt forming;
(2) introducing dinitrogen trioxide into a diazonium salt tubular reactor at the flow rate of 0.5g/min, carrying out diazotization reaction at the temperature of-6 ℃, allowing a diazonium salt solution and an acid solution generated by the reaction to enter a diazonium salt temporary storage kettle, carrying out continuous centrifugation treatment, drying the diazonium salt obtained by centrifugation, carrying out thermal decomposition treatment on the dried diazonium salt at the temperature of 600-DEG C, and controlling the thermal decomposition rate to be 2.5 g/min; concentrating the mother liquor after centrifugal treatment until the mass concentration of the fluoboric acid in the feed liquid is 25%, then using the concentrated mother liquor as a fluorination reagent for the salt-forming reaction in the step (1), and reusing the waste water obtained during concentration for preparing a fluoboric acid solution and using the solution in the salt-forming reaction in the step (1);
(3) spraying and absorbing gas generated in the thermal decomposition treatment of the diazonium salt in the step (2) by adopting hydrofluoric acid, layering the liquid after spraying and absorbing, pumping an oil layer obtained by layering into a rectifying tower for rectifying treatment, controlling the temperature at the top of the tower to be 80 ℃ and the temperature at the bottom of the tower to be 105 ℃ during rectifying treatment, collecting a target product, and using a water layer obtained by layering for preparing a fluoboric acid solution and reusing the water layer in the salt forming reaction in the step (1); solid waste generated in the thermal decomposition is used as an adsorbent for wastewater treatment.
Example 5
(1) Pumping a fluoboric acid solution with the mass concentration of 25% and m-amino benzotrifluoride into a salt forming microchannel reactor at the flow rates of 11g/min and 1.75g/min respectively to perform salt forming reaction at the temperature of 10 ℃, and entering into a diazonium salt tubular reactor after salt forming;
(2) introducing dinitrogen trioxide into a diazonium salt tubular reactor at the flow rate of 0.45g/min, carrying out diazotization reaction at the temperature of-5 ℃, allowing a diazonium salt solution and an acid solution generated by the reaction to enter a diazonium salt temporary storage kettle, carrying out continuous centrifugation treatment, drying the diazonium salt obtained by centrifugation, and carrying out thermal decomposition treatment on the dried diazonium salt at the temperature of 650 ℃, wherein the thermal decomposition rate is controlled to be 2.5 g/min; concentrating the mother liquor after centrifugal treatment until the mass concentration of the fluoboric acid is 25%, then using the concentrated mother liquor as a fluorination reagent in the salt forming reaction in the step (1), and reusing the waste water obtained during concentration in preparing the fluoboric acid solution and in the salt forming reaction in the step (1);
(3) spraying and absorbing gas generated in the thermal decomposition treatment of the diazonium salt in the step (2) by adopting hydrofluoric acid, layering the liquid after spraying and absorbing, pumping an oil layer obtained by layering into a rectifying tower for rectifying treatment, controlling the temperature at the top of the tower to be 80 ℃ and the temperature at the bottom of the tower to be 105 ℃ during rectifying treatment, collecting a target product, and using a water layer obtained by layering for preparing a fluoboric acid solution and reusing the water layer in the salt forming reaction in the step (1); solid waste generated in the thermal decomposition is used as an adsorbent for wastewater treatment.
The yields and purities of the target products obtained in the above examples of the present invention are shown in table 1.
TABLE 1
| Yield and content of | Purity% | |
| Example 1 | 96.5 | ＞99 |
| Example 2 | 96.8 | ＞99 |
| Example 3 | 96.5 | ＞99 |
| Example 4 | 96.7 | ＞99 |
| Example 5 | 96.8 | ＞99 |
The test results show that the yield of the target product prepared by the method provided by the invention is more than 96%, the purity is more than 99%, and the waste liquid and the solid slag in the production process can be recycled.
Claims (8)
1. A method for preparing 3-fluorotrifluorotoluene based on diazotization of dinitrogen trioxide is characterized by comprising the following steps:
(1) pumping the fluoboric acid solution and m-amino benzotrifluoride into a salifying microchannel reactor at a certain flow rate for salifying reaction, and entering into a diazonium salt tubular reactor after salifying;
(2) introducing dinitrogen trioxide into a diazonium salt tubular reactor to carry out diazotization reaction, allowing the diazonium salt solution and the acid solution generated by the reaction to enter a diazonium salt temporary storage kettle, carrying out continuous centrifugation, drying the diazonium salt obtained by centrifugation, and carrying out thermal decomposition treatment; concentrating the mother liquor after centrifugal treatment, concentrating the feed liquid to the concentration of the fluoboric acid solution before feeding, and reusing the waste water obtained during concentration for preparing the fluoboric acid solution;
(3) gas generated in the thermal decomposition treatment of the diazonium salt is sprayed and absorbed by acid liquor, and residue generated in the thermal decomposition treatment is collected and used as an adsorbent for wastewater treatment; and (3) layering the liquid after spraying and absorbing, pumping the oil layer obtained by layering into a rectifying tower for rectifying treatment, collecting a target product, and using the water layer obtained by layering for preparing the fluoboric acid solution and reusing the solution in the reaction.
2. The method for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization according to claim 1, characterized in that in step (1), the feed flow rates of the fluoroboric acid solution and the m-amino trifluorotoluene are respectively 8-12g/min and 1.5-1.8 g/min.
3. The method for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization according to claim 1, characterized in that, in the step (1), the mass concentration of the fluoboric acid solution is 20-30%.
4. The process for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization according to claim 1, characterized in that, in step (1), the temperature of the salt formation reaction is 10-20 ℃.
5. The process for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization according to claim 1, characterized in that, in step (2), the flow rate of the dinitrogen trioxide feed is controlled to be 0.3 to 0.5 g/min.
6. The method for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization according to claim 1, characterized in that, in step (2), the temperature of the diazotization reaction is-2 to-10 ℃.
7. The method for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization as claimed in claim 1, characterized in that, in step (2), the thermal decomposition temperature is 600-700 ℃, and the thermal decomposition rate is controlled to be 2-3 g/min.
8. The method for preparing 3-fluorotrifluorotoluene based on dinitrogen trioxide diazotization according to claim 1, characterized in that in step (3), the acid liquid is hydrofluoric acid.
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| CN (1) | CN114835555A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1817830A (en) * | 2006-03-09 | 2006-08-16 | 解卫宇 | Apparatus for producing aromatic fluorine compound and method for producing the same |
| CN101870636A (en) * | 2010-04-01 | 2010-10-27 | 大唐(杭州)医药化工有限公司 | Preparation method of 2-bromo-6-fluoronaphthalene |
| CN109894069A (en) * | 2019-04-23 | 2019-06-18 | 大连鼎燕医药化工有限公司 | It is used to prepare the thermal decomposition reactor and its system, continuous preparation process of fluorinated aromatic hydrocarbon |
| CN115312770A (en) * | 2022-02-10 | 2022-11-08 | 深圳市德方创域新能源科技有限公司 | Lithium supplement additive and preparation method and application thereof |
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2022
- 2022-03-17 CN CN202210263543.7A patent/CN114835555A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1817830A (en) * | 2006-03-09 | 2006-08-16 | 解卫宇 | Apparatus for producing aromatic fluorine compound and method for producing the same |
| CN101870636A (en) * | 2010-04-01 | 2010-10-27 | 大唐(杭州)医药化工有限公司 | Preparation method of 2-bromo-6-fluoronaphthalene |
| CN109894069A (en) * | 2019-04-23 | 2019-06-18 | 大连鼎燕医药化工有限公司 | It is used to prepare the thermal decomposition reactor and its system, continuous preparation process of fluorinated aromatic hydrocarbon |
| CN115312770A (en) * | 2022-02-10 | 2022-11-08 | 深圳市德方创域新能源科技有限公司 | Lithium supplement additive and preparation method and application thereof |
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| 沈新安: "《药物合成技术》", 河海大学出版社, pages: 54 - 55 * |
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