CN113582805A - Production process for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as raw material - Google Patents
Production process for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as raw material Download PDFInfo
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- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
- C07C17/20—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms
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- C07—ORGANIC CHEMISTRY
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- C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
- C07C201/06—Preparation of nitro compounds
- C07C201/08—Preparation of nitro compounds by substitution of hydrogen atoms by nitro groups
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Abstract
The invention relates to a method for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as a raw material, which comprises the following steps: step S1: carrying out nitration reaction on o-dichlorobenzene by using mixed acid consisting of concentrated sulfuric acid and concentrated nitric acid, deacidifying and dewatering after the nitration reaction, and carrying out fractional separation on an organic phase in a manner of firstly cooling and then heating for sweating to respectively obtain 2, 3-dichloronitrobenzene and 3, 4-dichloronitrobenzene; step S2: the method of the invention has the advantages of low energy consumption, low temperature and no three wastes, is the cleanest separation method at present, avoids the risk of high-temperature separation, and also avoids the solvent recovery of solvent crystallization. In addition, the mixed high oil can be further purified and separated according to the steps of the invention, so that the 2, 3-dinitrochlorobenzene is obtained, and the comprehensive utilization efficiency of the materials is improved.
Description
Technical Field
The invention relates to a production process for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as a raw material, belonging to the technical field of preparation methods of high-purity 2, 4-dichlorofluorobenzene.
Background
2-fluoro-3-chloronitrobenzene, 4-fluoro-3-chloronitrobenzene, 2, 6-dichlorofluorobenzene, 2, 4-dichlorofluorobenzene, 2,3, 4-trifluoronitrobenzene and 2, 4-dichloro-5-fluoro acetophenone are key intermediates for preparing quinolone medicaments and pesticides such as ciprofloxacin, norfloxacin hydrochloride, ofloxacin and the like.
Chinese patent 92107812.9 reports that o-dichlorobenzene as raw material is nitrified by mixed acid of concentrated nitric acid and concentrated sulfuric acid, the dried organic layer is subjected to fluorination reaction under the action of dimethyl sulfoxide and potassium fluoride, 4-fluoro-3-chloronitrobenzene with the content of 98% is separated and purified, and chlorine is introduced into the organic layer in a molten state to generate 2, 4-dichlorofluorobenzene.
In the prior art, the rectification separation method is difficult to separate, and nitro compounds are easy to decompose and possibly explode at high temperature, so that great potential safety hazards exist. Therefore, the invention aims to solve the technical problem of providing a production process for producing high-purity 2, 4-dichlorofluorobenzene by using o-dichlorobenzene as a raw material, which is purely physical and high in safety.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provides a production process for producing high-purity 2, 4-dichlorofluorobenzene by using o-dichlorobenzene as a raw material. The method is based on the organic phase obtained after the nitration of the raw material of o-dichlorobenzene, adopts a physical separation method, and has the advantages of low energy consumption, no pollution, high product quality, safety and reliability.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a production process for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as a raw material is characterized by comprising the following steps:
step S1: carrying out nitration reaction on o-dichlorobenzene by using mixed acid consisting of concentrated sulfuric acid and concentrated nitric acid, deacidifying and dewatering after the nitration reaction, and carrying out fractional separation on an organic phase in a manner of firstly cooling and then heating for sweating to respectively obtain 2, 3-dichloronitrobenzene and 3, 4-dichloronitrobenzene;
step S2: carrying out fluorination reaction and chlorination reaction on the 3, 4-dichloronitrobenzene prepared in the step S1 to obtain 2, 4-dichlorofluorobenzene;
in step S1, the stepwise separation steps of first cooling and then heating for sweating are as follows:
s11, conveying the organic phase into a crystallizer, and cooling to 15 +/-1 ℃;
step S12: step S1, gradually heating the cooled organic phase to make the crystal sweat;
step S13, collecting mixed low oil at 30-40 ℃ in the process of heating and sweating, wherein the mixed low oil contains 2.3-dinitrochlorobenzene with the volume fraction of 30 +/-1%;
step S14: collecting mixed high oil at 40-45 ℃, wherein the mixed high oil contains 2.3-dinitrochlorobenzene with the volume fraction of 10 +/-1%;
step S15: finally obtaining the 3, 4-dichloronitrobenzene crystals with the purity of more than 99.5 percent.
Preferably, the volume ratio of the o-dichlorobenzene to the mixed acid is 1:1.5-2, the nitration reaction temperature is 90-95 ℃, and the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid according to the mass ratio of 2-3: 1.
Preferably, potassium fluoride is used for the fluorination reaction, the fluorination reaction is carried out in tetramethylammonium chloride and in the absence of solvent, and the reaction temperature is 165 +/-5 ℃; wherein the molar ratio of the 3, 4-dichloronitrobenzene to the potassium fluoride is 1:1, and the molar ratio of the 3, 4-dichloronitrobenzene to the tetramethylammonium chloride is 20: 1.
Preferably, the chlorination reaction directly reacts with chlorine without a solvent, and the temperature of the chlorination reaction is 170-180 ℃.
Preferably, in step S11, the cooling rate of the mixed mother liquor in the crystallizer is 0.1-0.2 ℃/min, and the final temperature of cooling is controlled to be 15 ± 0.5 ℃.
Preferably, in step S11, the cooling rate of the mixed mother liquor in the crystallizer is 0.15 ℃/min.
Preferably, in step S12, the temperature-rising rate of temperature-rising sweating is 0.05-0.08 ℃/min, the final temperature of temperature-rising sweating is controlled at 50-64 ℃, and the total time of temperature-rising sweating is controlled at 10-12 hours.
Preferably, the heating rate of the heating and sweating is 0.06 ℃/min.
The invention has the beneficial effects that: the production process has the advantages of low energy consumption, low temperature and no three wastes, is the cleanest separation method at present, avoids the risk of high-temperature separation, and also avoids the solvent recovery of a solvent crystallization method. In addition, the mixed high oil can be further purified and separated according to the steps of the invention, so that the 2, 3-dinitrochlorobenzene is obtained, and the comprehensive utilization efficiency of the materials is improved.
Detailed Description
The technical solution of the present invention will be further specifically described below by way of specific examples.
In examples 1 to 3 of the present invention, all the crystallizers used were commercially available conventional crystallizers, and each raw material was a commercially available conventional raw material.
Example 1:
a production process for producing high-purity 2, 4-dichlorofluorobenzene by using o-dichlorobenzene as a raw material comprises the following steps:
step S1: carrying out nitration reaction on o-dichlorobenzene by using mixed acid consisting of concentrated sulfuric acid and concentrated nitric acid, deacidifying and dewatering after the nitration reaction, and carrying out fractional separation on an organic phase in a manner of firstly cooling and then heating for sweating to respectively obtain 2, 3-dichloronitrobenzene and 3, 4-dichloronitrobenzene;
step S2: carrying out fluorination reaction and chlorination reaction on the 3, 4-dichloronitrobenzene prepared in the step S1 to obtain 2, 4-dichlorofluorobenzene;
in step S1, the stepwise separation steps of first cooling and then heating for sweating are as follows:
s11, conveying the organic phase into a crystallizer, and cooling to 15 ℃;
step S12: step S1, gradually heating the cooled organic phase to make the crystal sweat;
step S13, collecting mixed low oil at 30-32 ℃ in the process of heating and sweating, wherein the mixed low oil contains 2.3-dinitrochlorobenzene with the volume fraction of 30%;
step S14: collecting mixed high oil at 40-42 ℃, wherein the mixed high oil contains 2.3-dinitrochlorobenzene with the volume fraction of 10%;
step S15: finally obtaining the 3, 4-dichloronitrobenzene crystals with the purity of more than 99.5 percent.
In example 1, the volume ratio of o-dichlorobenzene to mixed acid is 1:1.5, the nitration reaction temperature is 90 ℃, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid according to the mass ratio of 2:1, potassium fluoride is used for fluorination reaction, the fluorination reaction is carried out in tetramethylammonium chloride and in the absence of solvent, and the reaction temperature is 165 +/-2 ℃; wherein the molar ratio of the 3, 4-dichloronitrobenzene to the potassium fluoride is 1:1, the molar ratio of the 3, 4-dichloronitrobenzene to the tetramethylammonium chloride is 20:1, the chlorination reaction is directly reacted with chlorine gas without solvent, the temperature of the chlorination reaction is 170 ℃, in step S11, the cooling rate of an organic phase in a crystallizer is 0.1 ℃/min, the final temperature of the cooling is controlled at 15 ℃, in step S12, the heating rate of the heating and sweating is 0.05 ℃/min, and the final temperature of the heating and sweating is controlled at 50 ℃.
Example 2:
a production process for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as a raw material is characterized by comprising the following steps:
step S1: carrying out nitration reaction on o-dichlorobenzene by using mixed acid consisting of concentrated sulfuric acid and concentrated nitric acid, deacidifying and dewatering after the nitration reaction, and carrying out fractional separation on an organic phase in a manner of firstly cooling and then heating for sweating to respectively obtain 2, 3-dichloronitrobenzene and 3, 4-dichloronitrobenzene;
step S2: carrying out fluorination reaction and chlorination reaction on the 3, 4-dichloronitrobenzene prepared in the step S1 to obtain 2, 4-dichlorofluorobenzene;
in step S1, the stepwise separation steps of first cooling and then heating for sweating are as follows:
s11, conveying the organic phase into a crystallizer, and cooling to 15 ℃;
step S12: step S1, gradually heating the cooled organic phase to make the crystal sweat;
step S13, collecting mixed low oil at 38-40 ℃ in the process of heating and sweating, wherein the mixed low oil contains 2.3-dinitrochlorobenzene with the volume fraction of 30 +/-1%;
step S14: collecting mixed high oil at 43-45 ℃, wherein the mixed high oil contains 2.3-dinitrochlorobenzene with the volume fraction of 10%;
step S15: finally obtaining the 3, 4-dichloronitrobenzene crystals with the purity of more than 99.5 percent.
In example 2, the volume ratio of o-dichlorobenzene to mixed acid is 1:2, the nitration reaction temperature is 95 ℃, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid according to the mass ratio of 3:1, potassium fluoride is used for fluorination reaction, the fluorination reaction is carried out in tetramethylammonium chloride and in the absence of solvent, and the reaction temperature is 165 +/-1 ℃; wherein the molar ratio of the 3, 4-dichloronitrobenzene to the potassium fluoride is 1:1, the molar ratio of the 3, 4-dichloronitrobenzene to the tetramethylammonium chloride is 20:1, the chlorination reaction is directly reacted with chlorine gas without solvent, the temperature of the chlorination reaction is 180 ℃, in step S11, the cooling rate of an organic phase in a crystallizer is 0.2 ℃/min, the final temperature of the cooling is controlled at 15 ℃, in step S12, the heating rate of the heating and sweating is 0.08 ℃/min, and the final temperature of the heating and sweating is controlled at 64 ℃.
Example 3:
a production process for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as a raw material is characterized by comprising the following steps:
step S1: carrying out nitration reaction on o-dichlorobenzene by using mixed acid consisting of concentrated sulfuric acid and concentrated nitric acid, deacidifying and dewatering after the nitration reaction, and carrying out fractional separation on an organic phase in a manner of firstly cooling and then heating for sweating to respectively obtain 2, 3-dichloronitrobenzene and 3, 4-dichloronitrobenzene;
step S2: carrying out fluorination reaction and chlorination reaction on the 3, 4-dichloronitrobenzene prepared in the step S1 to obtain 2, 4-dichlorofluorobenzene;
in step S1, the stepwise separation steps of first cooling and then heating for sweating are as follows:
s11, conveying the organic phase into a crystallizer, and cooling to 15 ℃;
step S12: step S1, gradually heating the cooled organic phase to make the crystal sweat;
step S13, collecting mixed low oil at 35-38 ℃ in the process of heating and sweating, wherein the mixed low oil contains 2.3-dinitrochlorobenzene with the volume fraction of 30%;
step S14: collecting mixed high oil at 42-43 ℃, wherein the mixed high oil contains 2.3-dinitrochlorobenzene with the volume fraction of 10%;
step S15: finally obtaining the 3, 4-dichloronitrobenzene crystals with the purity of more than 99.5 percent.
In example 3, the volume ratio of o-dichlorobenzene to mixed acid is 1:2, the nitration reaction temperature is 92 ℃, the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid according to the mass ratio of 3:1, potassium fluoride is used for fluorination reaction, the fluorination reaction is carried out in tetramethylammonium chloride and in the absence of solvent, and the reaction temperature is 165 +/-2 ℃; wherein the molar ratio of the 3, 4-dichloronitrobenzene to the potassium fluoride is 1:1, the molar ratio of the 3, 4-dichloronitrobenzene to the tetramethylammonium chloride is 20:1, the chlorination reaction is directly reacted with chlorine gas without solvent, the temperature of the chlorination reaction is 176 ℃, in step S11, the cooling rate of an organic phase in a crystallizer is 0.15 ℃/min, in step S12, the heating rate of heating and sweating is 0.06 ℃/min, and the final temperature of heating and sweating is controlled at 55 ℃.
The production process has the advantages of low energy consumption, low temperature and no three wastes, is the cleanest separation method at present, avoids the risk of high-temperature separation, and also avoids the solvent recovery of a solvent crystallization method. In addition, the mixed high oil can be further purified and separated according to the steps of the invention, so that the 2, 3-dinitrochlorobenzene is obtained, and the comprehensive utilization efficiency of the materials is improved.
The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.
Claims (8)
1. A method for producing high-purity 2, 4-dichlorofluorobenzene by taking o-dichlorobenzene as a raw material is characterized by comprising the following steps:
step S1: carrying out nitration reaction on o-dichlorobenzene by using mixed acid consisting of concentrated sulfuric acid and concentrated nitric acid, deacidifying and dewatering after the nitration reaction, and carrying out fractional separation on an organic phase in a manner of firstly cooling and then heating for sweating to respectively obtain 2, 3-dichloronitrobenzene and 3, 4-dichloronitrobenzene;
step S2: carrying out fluorination reaction and chlorination reaction on the 3, 4-dichloronitrobenzene prepared in the step S1 to obtain 2, 4-dichlorofluorobenzene;
in step S1, the stepwise separation steps of first cooling and then heating for sweating are as follows:
s11, conveying the organic phase into a crystallizer, and cooling to 15 +/-1 ℃;
step S12: step S1, gradually heating the cooled organic phase to make the crystal sweat;
step S13, collecting mixed low oil at 30-40 ℃ in the process of heating and sweating, wherein the mixed low oil contains 2.3-dinitrochlorobenzene with the volume fraction of 30 +/-1%;
step S14: collecting mixed high oil at 40-45 ℃, wherein the mixed high oil contains 2.3-dinitrochlorobenzene with the volume fraction of 10 +/-1%;
step S15: finally obtaining the 3, 4-dichloronitrobenzene crystals with the purity of more than 99.5 percent.
2. The method for producing high-purity 2, 4-dichlorofluorobenzene using o-dichlorobenzene as a raw material according to claim 1, wherein the volume ratio of o-dichlorobenzene to mixed acid is 1:1.5-2, the nitration reaction temperature is 90-95 ℃, and the mixed acid is composed of concentrated sulfuric acid and concentrated nitric acid in a mass ratio of 2-3: 1.
3. The method for producing high-purity 2, 4-dichlorofluorobenzene using o-dichlorobenzene as a raw material according to claim 1, wherein the fluorination is carried out using potassium fluoride, and the fluorination is carried out using tetramethylammonium chloride in the absence of a solvent at a temperature of 165 ± 5 ℃; wherein the molar ratio of the 3, 4-dichloronitrobenzene to the potassium fluoride is 1:1, and the molar ratio of the 3, 4-dichloronitrobenzene to the tetramethylammonium chloride is 20: 1.
4. The method for producing high-purity 2, 4-dichlorofluorobenzene by using o-dichlorobenzene as a raw material according to claim 1, wherein the chlorination reaction is directly reacted with chlorine gas without a solvent, and the temperature of the chlorination reaction is 170-180 ℃.
5. The method for producing high-purity 2, 4-dichlorofluorobenzene according to claim 1, wherein in the step S11, the cooling rate of the mixed mother liquor in the crystallizer is 0.1-0.2 ℃/min, and the final cooling temperature is controlled to 15 +/-0.5 ℃.
6. The method for producing high-purity 2, 4-dichlorofluorobenzene using o-dichlorobenzene as a raw material according to claim 5, wherein in the step S11, the cooling rate of the mixed mother liquor in the crystallizer is 0.15 ℃/min.
7. The method for producing high-purity 2, 4-dichlorofluorobenzene starting from o-dichlorobenzene as claimed in claim 1, wherein in step S12, the heating rate for raising temperature and sweating is 0.05-0.08 ℃/min, the final temperature for raising temperature and sweating is controlled to be 50-64 ℃, and the total time for raising temperature and sweating is controlled to be 10-12 hours.
8. The method for producing high-purity 2, 4-dichlorofluorobenzene from o-dichlorobenzene as a raw material according to claim 7, wherein the heating rate for heating and sweating is 0.06 ℃/min.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117384004A (en) * | 2023-12-11 | 2024-01-12 | 山东国邦药业有限公司 | Synthesis method of 2, 4-dichloro fluorobenzene |
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