CN113896611A - Preparation method of 3-chloro-4-fluorobenzotrifluoride - Google Patents
Preparation method of 3-chloro-4-fluorobenzotrifluoride Download PDFInfo
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- CN113896611A CN113896611A CN202111227217.2A CN202111227217A CN113896611A CN 113896611 A CN113896611 A CN 113896611A CN 202111227217 A CN202111227217 A CN 202111227217A CN 113896611 A CN113896611 A CN 113896611A
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- diazonium salt
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- fluorotrifluorotoluene
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- BKHVEYHSOXVAOP-UHFFFAOYSA-N 2-chloro-1-fluoro-4-(trifluoromethyl)benzene Chemical compound FC1=CC=C(C(F)(F)F)C=C1Cl BKHVEYHSOXVAOP-UHFFFAOYSA-N 0.000 title claims abstract description 16
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000012954 diazonium Substances 0.000 claims abstract description 39
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 26
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 claims abstract description 22
- 150000001989 diazonium salts Chemical class 0.000 claims abstract description 19
- 239000002253 acid Substances 0.000 claims abstract description 17
- 238000000197 pyrolysis Methods 0.000 claims abstract description 15
- MBBUTABXEITVNY-UHFFFAOYSA-N 2-chloro-4-(trifluoromethyl)aniline Chemical compound NC1=CC=C(C(F)(F)F)C=C1Cl MBBUTABXEITVNY-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052751 metal Inorganic materials 0.000 claims abstract description 12
- 239000002184 metal Substances 0.000 claims abstract description 12
- 235000010288 sodium nitrite Nutrition 0.000 claims abstract description 11
- IXRQNZAJLHWMQQ-UHFFFAOYSA-N 1-chloro-2,3,4,6-tetrafluoro-5-methylbenzene Chemical compound CC1=C(F)C(F)=C(F)C(Cl)=C1F IXRQNZAJLHWMQQ-UHFFFAOYSA-N 0.000 claims abstract description 6
- 238000006193 diazotization reaction Methods 0.000 claims abstract description 3
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims abstract description 3
- 238000004227 thermal cracking Methods 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 30
- 239000000243 solution Substances 0.000 claims description 25
- -1 arylamine diazonium salt Chemical class 0.000 claims description 17
- 238000003756 stirring Methods 0.000 claims description 17
- 150000004982 aromatic amines Chemical class 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 238000001816 cooling Methods 0.000 claims description 12
- 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 11
- 229910000856 hastalloy Inorganic materials 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 8
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 7
- 229920002472 Starch Polymers 0.000 claims description 7
- 238000001035 drying Methods 0.000 claims description 7
- 229910052700 potassium Inorganic materials 0.000 claims description 7
- 239000011591 potassium Substances 0.000 claims description 7
- 239000002994 raw material Substances 0.000 claims description 7
- 239000008107 starch Substances 0.000 claims description 7
- 239000007769 metal material Substances 0.000 claims description 6
- 238000001291 vacuum drying Methods 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- 238000000967 suction filtration Methods 0.000 claims description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-O diazynium Chemical compound [NH+]#N IJGRMHOSHXDMSA-UHFFFAOYSA-O 0.000 claims description 4
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 239000002904 solvent Substances 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- 238000009776 industrial production Methods 0.000 abstract description 4
- 230000008878 coupling Effects 0.000 abstract description 2
- 238000010168 coupling process Methods 0.000 abstract description 2
- 238000005859 coupling reaction Methods 0.000 abstract description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 239000007788 liquid Substances 0.000 description 6
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical class [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 4
- 238000007605 air drying Methods 0.000 description 4
- 238000009833 condensation Methods 0.000 description 4
- 230000005494 condensation Effects 0.000 description 4
- 239000004005 microsphere Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 3
- 229940079593 drug Drugs 0.000 description 3
- 239000003814 drug Substances 0.000 description 3
- 229910052731 fluorine Inorganic materials 0.000 description 3
- 230000005389 magnetism Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000000460 chlorine Substances 0.000 description 2
- 229910052801 chlorine Inorganic materials 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 150000003983 crown ethers Chemical class 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000000575 pesticide Substances 0.000 description 2
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- XILPLWOGHPSJBK-UHFFFAOYSA-N 1,2-dichloro-4-(trifluoromethyl)benzene Chemical compound FC(F)(F)C1=CC=C(Cl)C(Cl)=C1 XILPLWOGHPSJBK-UHFFFAOYSA-N 0.000 description 1
- OORBDHOQLZRIQR-UHFFFAOYSA-N 1-fluoro-4-methyl-2-nitrobenzene Chemical compound CC1=CC=C(F)C([N+]([O-])=O)=C1 OORBDHOQLZRIQR-UHFFFAOYSA-N 0.000 description 1
- 229910015900 BF3 Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 239000000010 aprotic solvent Substances 0.000 description 1
- 150000001491 aromatic compounds Chemical class 0.000 description 1
- 230000004071 biological effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- WTEOIRVLGSZEPR-UHFFFAOYSA-N boron trifluoride Chemical compound FB(F)F WTEOIRVLGSZEPR-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000005660 chlorination reaction Methods 0.000 description 1
- 125000001309 chloro group Chemical group Cl* 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 125000001153 fluoro group Chemical group F* 0.000 description 1
- 238000010813 internal standard method Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 150000008048 phenylpyrazoles Chemical class 0.000 description 1
- 235000003270 potassium fluoride Nutrition 0.000 description 1
- 239000011698 potassium fluoride Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000003786 synthesis reaction Methods 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
- 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
- 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 discloses a preparation method of 3-chloro-4-fluorotrifluorotoluene, which comprises the following steps: reacting 3-chloro-4-amino benzotrifluoride with hydrochloric acid and sodium nitrite to carry out amino diazotization, adding fluoboric acid to generate fluoboric acid diazonium salt, and carrying out thermal cracking in a metal bath to obtain a product, namely 3-chloro-4-fluoro benzotrifluoride; the invention can improve the heat conduction efficiency during pyrolysis by using metal bath, simultaneously reduces self coupling of diazonium salt, improves selectivity and yield, is environment-friendly, has low cost and is suitable for industrial production;
Description
Technical Field
The invention relates to a preparation method of 3-chloro-4-fluorobenzotrifluoride.
Background
3-chloro-4-fluorobenzotrifluoride is an important fluoride, has unique biological activity of fluorine-containing aromatic compounds, and is widely applied to synthesis of medicines and pesticides. The appearance of the liquid is colorless transparent liquid, and the chemical structural formula is as follows:
because the fluorine atom has high electron cloud density and large electronegativity, the introduction of the fluorine-containing group leads the compound to have unique properties of good thermal stability, oxidation resistance and the like. 3-chloro-4-fluorobenzotrifluoride is an important intermediate of medicines and pesticides, and can be used for synthesizing phenyl pyrazoles, phenylenediethers and other medicines. Therefore, the optimization of the preparation method is of great significance to industrial production.
According to the literature reports, the existing preparation methods of 3-chloro-4-fluorobenzotrifluoride mainly comprise the following methods.
The first method, disclosed in patent CN 102267871 a, is to react 3, 4-dichlorotrifluorotoluene as a raw material with anhydrous potassium fluoride in an aprotic solvent in the presence of a catalyst containing a copper halide and crown ether to obtain 3-chloro-4-fluorotrifluorotoluene. The method involves a catalyst with higher crown ether equivalent lattice, so that the cost is higher, and the method has the defects of complex post-treatment process, environmental pollution and the like.
Secondly, according to the preparation method of 3-chloro-4-fluorobenzotrifluoride disclosed in the US patent US4582948, 4-fluoro-3-nitrotoluene is taken as a raw material, chlorine is introduced at the temperature of 290-450 ℃, nitro is replaced by chlorine atoms, and the distillate is washed, dried and distilled under normal pressure to obtain the product. The method is used for chlorination at high temperature, and the reaction conditions are harsh, so that industrial production is difficult to carry out.
And thirdly, reacting 3-chloro-4-amino benzotrifluoride with sodium nitrite, treating with fluoboric acid to prepare the diazonium fluoroborate, and directly pyrolyzing the prepared diazonium fluoroborate to generate the 3-chloro-4-fluoro benzotrifluoride. The method easily causes the diazonium salt to be heated unevenly, the reaction byproducts are more and the yield is lower in the pyrolysis process.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a preparation method of 3-chloro-4-fluorobenzotrifluoride, according to the route of the third method, a metal bath is adopted for carrying out thermal decomposition reaction in the thermal decomposition operation of the diazonium fluoroborate, metal microspheres are added to ensure that the metal microspheres are heated uniformly, and the traditional industrial preparation process is improved to improve the selectivity and the yield of the reaction.
The technical scheme of the invention is as follows:
a method for preparing 3-chloro-4-fluorobenzotrifluoride, the method comprising:
reacting 3-chloro-4-amino benzotrifluoride with hydrochloric acid and sodium nitrite to carry out amino diazotization, adding fluoboric acid to generate fluoboric acid diazonium salt, and then carrying out thermal cracking (Hieman method) in metal bath to obtain a product, namely 3-chloro-4-fluoro benzotrifluoride;
the metal materials used in the metal bath are: c276 Hastelloy (50-200 μm), 316L stainless steel (50-200 μm), 18/8 stainless steel (50-200 μm) or titanium material (50-200 μm), preferably C276 Hastelloy;
the reaction formula is as follows:
specifically, the preparation method of the 3-chloro-4-fluorobenzotrifluoride comprises the following steps of;
(1) dropwise adding the raw material 3-chloro-4-amino benzotrifluoride into concentrated hydrochloric acid (35-37%) while stirring, heating to 40-50 ℃ until the raw material is completely dissolved, then cooling to-10-0 ℃, dropwise adding a sodium nitrite aqueous solution, and detecting the reaction end point by using potassium iodide-starch test paper to obtain arylamine diazonium salt (the arylamine diazonium salt is directly used for the next reaction without being separated from the system);
wherein the mass ratio of the 3-chloro-4-amino benzotrifluoride to the hydrochloric acid is 1: 0.5-10, preferably 1: 1-5;
when the potassium iodide-starch test paper turns blue, the reaction end point is obtained, and the excessive sodium nitrite is removed by sulfamic acid; detecting the actual content of the arylamine diazonium salt in the system by a liquid phase internal standard method;
(2) preparing a fluoboric acid solution, cooling to-10-0 ℃, adding the solution into the arylamine diazonium salt obtained in the step (1), fully stirring (1-50 min), carrying out suction filtration, and carrying out vacuum drying (40-60 ℃, 2-7 h) to obtain the arylamine fluoboric acid diazonium salt;
the concentration of the fluoboric acid solution is 5-8 mol/L, and the solvent is water;
the mass ratio of the fluoroboric acid to the arylamine diazonium salt is 1: 1-15, preferably 1: 1-6;
(3) mixing the arylamine fluoborate diazonium salt obtained in the step (2) with a metal material, heating to 140-280 ℃ under stirring for pyrolysis, condensing and collecting a distillate in the pyrolysis process, washing and drying the distillate, and distilling at normal pressure to collect a product at 134-138 ℃ to obtain 3-chloro-4-fluoro benzotrifluoride;
the mass ratio of the arylamine fluoboric acid diazonium salt to the metal material is 2-3: 1.
compared with the prior art, the invention has the advantages that;
the raw materials selected in the reaction are simple and easy to obtain, and the method does not use metal catalysts and organic solvents, thereby reducing the treatment cost, reducing the environmental protection pressure and avoiding the environmental pollution. And the reaction time is short, the production efficiency is obviously improved, and the method is suitable for industrial production.
The metal bath C276 hastelloy microspheres can improve the heat conduction efficiency during pyrolysis, reduce self coupling of diazonium salt and improve selectivity and yield. The C276 hastelloy has strong corrosion resistance, can be repeatedly used after being simply washed, effectively reduces the manufacturing cost of a target product, and improves the economic benefit.
Detailed Description
The invention is further described below by means of specific examples, without the scope of protection of the invention being limited thereto.
The metal microspheres used in the examples are commercially available through conventional routes.
50-200 μm of C276 Hastelloy, density: 8.9g/cm3Melting point: 1325-1370 ℃, magnetism: none. Mainly resistant to chlorine and moistureThe oxidizing chloride, the chloride solution, the sulfuric acid and the oxidizing salt have good corrosion resistance in low-temperature and medium-temperature hydrochloric acid.
316L stainless steel 50-200 μm, density: 7.8g/cm3Melting point: 1200-1300 ℃, magnetism: none.
18/8 stainless steel 50-200 μm, density: 7.93g/cm3Melting point: 1398-1454 ℃, magnetism: none.
Example one
Adding 165mL (containing 2mol) of concentrated hydrochloric acid into a 1000mL reaction bottle, stirring and dropwise adding 196g (1mol) of 3-chloro-4-amino benzotrifluoride, heating to 45 ℃ until the solution is completely mixed, then cooling to 0 ℃, dropwise adding a solution of 1.1mol of sodium nitrite and 100mL of water, keeping the temperature not more than 5 ℃ in the dropwise adding process, and detecting the end point by using potassium iodide-starch test paper to obtain the arylamine diazonium salt. And preparing a fluoroboric acid solution by using a flask, dissolving 114g of fluoroboric acid in 200mL of water until the fluoroboric acid is completely dissolved, cooling to 0 ℃, pouring the solution into the prepared ice-cold arylamine diazonium salt under stirring, fully stirring for 10min, carrying out suction filtration, air drying and vacuum drying to obtain the arylamine fluoroboric diazonium salt. 275.5g of arylamine fluoborate diazonium salt and 100g C276 Hastelloy particles are added into a 3L flask, stirred and heated to 200 ℃ for pyrolysis for 15min, a condenser is used for condensation and distillate collection in the pyrolysis process, and BF is performed3Absorbing with hot water, putting the generated nitrogen into the air, washing the distillate twice with 50mL of saturated sodium chloride solution, drying with anhydrous sodium sulfate, distilling at normal pressure, and recovering the product of the distillate at 134-138 ℃ to obtain 175.12g of colorless transparent liquid with the yield of 88%.
Example two
Adding 165mL (containing 2mol) of concentrated hydrochloric acid into a 1000mL reaction bottle, stirring and dropwise adding 196g (1mol) of 3-chloro-4-amino benzotrifluoride, heating to 45 ℃ until the solution is completely mixed, then cooling to 0 ℃, dropwise adding a solution of 1.1mol of sodium nitrite and 100mL of water, keeping the temperature not more than 5 ℃ in the dropwise adding process, and detecting the end point by using potassium iodide-starch test paper to obtain the arylamine diazonium salt. Preparing fluoroboric acid solution in a flask, dissolving 114g fluoroboric acid in 200mL water, cooling to 0 deg.C, adding ice-cold arylamine diazonium salt under stirring, and fillingStirring for 10min, filtering, drying in air, and vacuum drying to obtain arylamine fluoboric acid diazonium salt. 275.5g of arylamine fluoborate diazonium salt and 100g of 18/8 g of stainless steel metal particles are added into a 3L flask, stirred and heated to 200 ℃ for pyrolysis for 15min, a condenser is used for condensation and distillate collection in the pyrolysis process, and BF is obtained3Absorbing with hot water, putting the generated nitrogen into the air, washing the distillate twice with 50mL of saturated sodium chloride solution, drying with anhydrous sodium sulfate, distilling at normal pressure, and recovering the product of the distillate at 134-138 ℃ to obtain 167.16g of colorless transparent liquid with the yield of 84%.
EXAMPLE III
Adding 247.5mL (containing 3mol of HCl) of concentrated hydrochloric acid into a 1000mL reaction bottle, stirring and dropwise adding 196g (1mol) of 3-chloro-4-amino benzotrifluoride, heating to 45 ℃ until the solution is completely mixed, then cooling to 0 ℃, dropwise adding a solution of 1.1mol of sodium nitrite and 100mL of water, keeping the temperature not more than 5 ℃ in the dropwise adding process, and detecting the end point by using potassium iodide-starch test paper to obtain the arylamine diazonium salt. And preparing a fluoroboric acid solution by using a flask, dissolving 114g of fluoroboric acid in 200mL of water until the fluoroboric acid is completely dissolved, cooling to 0 ℃, pouring the solution into the prepared ice-cold arylamine diazonium salt under stirring, fully stirring for 10min, carrying out suction filtration, air drying and vacuum drying to obtain the arylamine fluoroboric diazonium salt. 275.5g of arylamine fluoborate diazonium salt and 100g C276 Hastelloy particles are added into a 3L flask, stirred and heated to 200 ℃ for pyrolysis for 15min, a condenser is used for condensation and distillate collection in the pyrolysis process, and BF is performed3Absorbing with hot water, putting the generated nitrogen into the air, washing the distillate twice with 50mL of saturated sodium chloride solution, drying with anhydrous sodium sulfate, distilling at normal pressure, and recovering the product of the distillate at 134-138 ℃ to obtain 163.18g of colorless transparent liquid with the yield of 82%.
Example four
Adding 330mL of concentrated hydrochloric acid (containing 4mol of HCl) into a 1000mL reaction bottle, stirring and dropwise adding 196g (1mol) of 3-chloro-4-amino benzotrifluoride, heating to 45 ℃ until the solution is completely mixed, then cooling to 0 ℃, dropwise adding a solution of 1.1mol of sodium nitrite and 100mL of water, keeping the temperature not more than 5 ℃ in the dropwise adding process, and detecting the end point by using potassium iodide-starch test paper to obtain the arylamine diazonium salt. Separately preparing boron fluoride by using a flaskAnd (3) dissolving 114g of fluoboric acid in 200mL of water until the fluoboric acid is completely dissolved, cooling to 0 ℃, pouring the solution into the prepared ice-cold arylamine diazonium salt under stirring, fully stirring for 10min, carrying out suction filtration, air drying and vacuum drying to obtain the arylamine fluoboric acid diazonium salt. 275.5g of arylamine fluoborate diazonium salt and 100g C276 Hastelloy particles are added into a 3L flask, stirred and heated to 180 ℃ for pyrolysis for 15min, a condenser is used for condensation and distillate collection in the pyrolysis process, and BF is performed3Absorbing with hot water, putting the generated nitrogen into the air, washing the distillate twice with 50mL of saturated sodium chloride solution, drying with anhydrous sodium sulfate, distilling at normal pressure, recovering the product at the temperature of 134-138 ℃ of the distillate to obtain colorless transparent liquid, 159.2g of which the yield is 80%.
Claims (6)
1. A method for preparing 3-chloro-4-fluorobenzotrifluoride, which is characterized by comprising the following steps:
reacting 3-chloro-4-amino benzotrifluoride with hydrochloric acid and sodium nitrite to carry out amino diazotization, adding fluoboric acid to generate fluoboric acid diazonium salt, and carrying out thermal cracking in a metal bath to obtain a product, namely 3-chloro-4-fluoro benzotrifluoride;
the metal materials used in the metal bath are: c276 Hastelloy, 316L stainless steel, 18/8 stainless steel or titanium material;
the reaction formula is as follows:
2. the process for producing 3-chloro-4-fluorotrifluorotoluene according to claim 1, wherein the process comprises;
(1) dropwise adding the raw material 3-chloro-4-amino benzotrifluoride into concentrated hydrochloric acid while stirring, heating to 40-50 ℃ until the raw material is completely dissolved, then cooling to-10-0 ℃, dropwise adding a sodium nitrite aqueous solution, and detecting the reaction end point by using potassium iodide-starch test paper to obtain arylamine diazonium salt;
(2) preparing a fluoboric acid solution, cooling to-10-0 ℃, adding the solution into the arylamine diazonium salt obtained in the step (1), fully stirring, performing suction filtration, and performing vacuum drying to obtain the arylamine fluoboric acid diazonium salt;
(3) mixing the arylamine fluoborate diazonium salt obtained in the step (2) with a metal material, heating to 140-280 ℃ under stirring for pyrolysis, condensing and collecting a distillate in the pyrolysis process, washing and drying the obtained distillate, and distilling at normal pressure to collect a product at 134-138 ℃ to obtain the 3-chloro-4-fluobenzotrifluoride.
3. The process for producing 3-chloro-4-fluorotrifluorotoluene according to claim 2, wherein in the step (1), the mass ratio of 3-chloro-4-aminotrifluorotoluene to hydrochloric acid is 1: 0.5 to 10.
4. The method according to claim 2, wherein in the step (2), the fluoroboric acid solution has a concentration of 5 to 8mol/L and the solvent is water.
5. The process for producing 3-chloro-4-fluorotrifluorotoluene according to claim 2, wherein in the step (2), the ratio of the amount of the substance of the fluoroboric acid to the substance of the arylamine diazonium salt is 1: 1 to 15.
6. The preparation method of 3-chloro-4-fluorotrifluorotoluene according to claim 2, wherein in the step (3), the mass ratio of the arylamine diazonium fluoroborate to the metal material is 2-3: 1.
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| CN104447183A (en) * | 2014-11-17 | 2015-03-25 | 联化科技(盐城)有限公司 | Method for preparing 2-bromine-5-trifluorotoluene chloride |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104447183A (en) * | 2014-11-17 | 2015-03-25 | 联化科技(盐城)有限公司 | Method for preparing 2-bromine-5-trifluorotoluene chloride |
Non-Patent Citations (1)
| Title |
|---|
| FAC. ENG.等: "A facile preparation of fluoropyridines from aminopyridines via diazotization and fluorodediazoniation in hydrogen fluoride or hydrogen fluoride-pyridine solutions", JOURNAL OF FLUORINE CHEMISTRY, vol. 33, no. 8, pages 435 - 438 * |
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