CN113929553B - Synthetic method of 2, 4-dichlorofluorobenzene - Google Patents
Synthetic method of 2, 4-dichlorofluorobenzene Download PDFInfo
- Publication number
- CN113929553B CN113929553B CN202111536018.XA CN202111536018A CN113929553B CN 113929553 B CN113929553 B CN 113929553B CN 202111536018 A CN202111536018 A CN 202111536018A CN 113929553 B CN113929553 B CN 113929553B
- Authority
- CN
- China
- Prior art keywords
- hydrogen fluoride
- reaction
- dichlorofluorobenzene
- dichloroaniline
- raw material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
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
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a synthesis method of 2, 4-dichlorofluorobenzene, belonging to the technical field of drug synthesis, wherein the synthesis method takes hydrogen fluoride as a solvent, 2, 4-dichloroaniline as a raw material, and trace water is added to promote the reaction, and firstly, a small amount of H is ionized by the hydrogen fluoride in the presence of trace water+，H+Combining with 2, 4-dichloroaniline to produce positively charged intermediate, then making the intermediate undergo the process of substitution reaction with hydrogen fluoride to produce ammonia and 2, 4-dichlorofluorobenzene, at the same time removing H+Reaction of ammonia with hydrogen fluoride to give ammonium fluoride salt, H+Continuously catalyzing the reaction of the first step; the synthesis method is simple, the raw material source is wide, the generated by-product ammonium fluoride can generate hydrogen fluoride after being recovered and treated by sulfuric acid to be used as a solvent, meanwhile, the generated ammonium sulfate can be used as a by-product, the whole process has no solid waste liquid waste, the selectivity is high, and the method is environment-friendly.
Description
Technical Field
The invention belongs to the technical field of drug synthesis, and particularly relates to a synthesis method of 2, 4-dichlorofluorobenzene.
Background
2, 4-dichlorofluorobenzene is an important intermediate for synthesizing novel antibacterial agent fluoroquinolone medicaments, is mainly used for synthesizing ciprofloxacin, mefloxacid and the like, is a main raw material for preparing products such as specific antipsychotic drugs of trifluperidol, trifluperfenidine, penfluridol, quinolone drugs of ciprofloxacin, enrofloxacin and the like, and is also used for identifying pesticide, ovicide, plastics and resin.
The synthesis route of the 2, 4-dichlorofluorobenzene is more, and the synthesis route can be divided into the following process lines according to the difference of main raw materials:
patent CN104496824B discloses a method for obtaining 2, 4-dichlorofluorobenzene by chlorination of 3-chloro-4-fluoronitrobenzene, which is a mainstream production process in the industry at present, but the method has harsh reaction conditions, requires high temperature of more than 200 ℃, and needs chlorine gas to replace nitro, and has high danger coefficient; meanwhile, the production of nitryl chloride tail gas with higher risk coefficient and greater pollution, the reaction difficulty and the tail gas treatment are main factors for restricting the development of the production route.
Patent CN108911944A discloses a method for preparing 2, 6-dichloro-3-fluoro acetophenone, which comprises the steps of putting the raw materials into a solvent, wherein the solvent is selected from one of the following: sulfolane, formic acid and acetic acid, wherein the using amount of a solvent is 1g: 1-5 mL; carrying out oxygen oxidation reaction under the catalysis of copper salt to obtain 2, 6-dichloro-3-fluorobenzoic acid; then 2, 6-dichloro-3-fluoro acetophenone is decarboxylated in the presence of a catalyst DBU and copper salt to obtain 2, 4-dichloro fluoro benzene. The process takes the byproduct of the Friedel-crafts acetylation process of the 2, 4-dichlorofluorobenzene as the raw material, and the 2, 4-dichlorofluorobenzene is prepared again through complicated steps, but the yield of the raw material is very low; the reaction process is long, and the reaction yield is low; the reaction conditions are harsh, and the used materials are polluted greatly; so that there is no industrial value.
Patent CN109851471A discloses a method for producing 2, 4-dichlorofluorobenzene in one step by using 1,2, 4-trichlorobenzene as a raw material, a calixarene and trimethylolpropane borate complex as a phase transfer catalyst, and spray-dried potassium fluoride as a fluorinating agent; the method has the advantages of less catalyst source and high price, the difficulty of substituting chlorine by fluorine is greatly increased due to the conjugation of a chlorine substituent to an ortho-para position, and the selectivity of the fluorination reaction is poor due to the positioning effect, so a large amount of unexpected byproducts are generated.
Patent CN108821939A discloses a synthetic method of ciprofloxacin intermediate 2, 4-dichlorofluorobenzene, which specifically relates to the technical field of pharmaceutical intermediates, and specifically comprises the following steps: stirring 2, 4-dichloroaniline hydrochloride and hydrochloric acid into slurry, and cooling; dissolving sodium nitrite in warm water, freezing to 0 ℃ for later use, adding boric acid into 40% hydrofluoric acid, and freezing to 0 ℃ for later use; adding crushed ice into the slurry, pouring sodium nitrite solution, fully stirring, filtering the reactant, cooling the filtrate to 0 ℃, pouring fluoroboric acid solution, separating out white crystal diazonium fluoroborate, stirring, filtering out crystals, and air-drying to obtain a crude product; heating, melting and decomposing the fluoboric acid diazonium salt, keeping stable boiling for 0.5h, then washing with water, distilling at normal pressure to obtain an orange-yellow distillate, drying, then fractionating, and collecting a fraction at a certain temperature to obtain 2, 4-dichlorofluorobenzene; however, the diazotization sandmeyer reaction is adopted in the reaction, substances such as sodium nitrite and boric acid are required in the reaction process, the reaction process is long, the generation of three wastes is high, and the yield is low.
Disclosure of Invention
The invention provides a synthesis method of 2, 4-dichlorofluorobenzene, which takes hydrogen fluoride as a solvent and 2, 4-dichloroaniline as a raw material to directly perform pressure fluorination to obtain the 2, 4-dichlorofluorobenzene, and has the advantages of simple synthesis method, wide raw material source, capability of generating hydrogen fluoride as the solvent for continuous use after sulfuric acid recovery treatment of generated by-product ammonium fluoride, capability of generating ammonium sulfate as the by-product for use, no solid waste liquid waste in the whole process, high selectivity and environmental friendliness.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a process for synthesizing 2, 4-dichlorofluorobenzene uses hydrogen fluoride as solvent, 2, 4-dichloroaniline as raw material and adds trace water to promote reaction, and includes ionizing a little H by hydrogen fluoride in the presence of trace water+，H+Combining with 2, 4-dichloroaniline to produce positively charged intermediate, then making the intermediate undergo the process of substitution reaction with hydrogen fluoride to produce ammonia and 2, 4-dichlorofluorobenzene, at the same time removing H+Reaction of ammonia with hydrogen fluoride to give ammonium fluoride salt, H+The first step reaction is continued to be catalyzed.
A process for synthesizing 2, 4-dichlorofluorobenzene includes fluoridation and recovery of raw material.
The fluorination reaction comprises the steps of adding 2, 4-dichloroaniline and water into a reaction kettle, then adding hydrogen fluoride in an ice bath, then closing the reaction kettle, slowly heating to the reaction temperature of 153-198 ℃, controlling the heating time to be 1h, then keeping the temperature for 12h, cooling to 50 ℃, releasing redundant hydrogen fluoride, cooling and liquefying the hydrogen fluoride, and then reusing the hydrogen fluoride as a reaction.
Preferably, the reaction temperature of the fluorination reaction is 188 ℃.
The molar ratio of the 2, 4-dichloroaniline to the hydrogen fluoride in the fluorination reaction is 1: 3-10.
Preferably, the molar ratio of 2, 4-dichloroaniline to hydrogen fluoride in the fluorination reaction is 1: 5.
The mass ratio of water to 2, 4-dichloroaniline in the fluorination reaction is 0.1-0.5: 100.
Preferably, the mass ratio of water to 2, 4-dichloroaniline in the fluorination reaction is 0.2-0.3: 100.
And (3) recovering the raw materials, namely adding water to the residual material liquid for dissolving and layering, separating a water outlet layer, then dropwise adding sulfuric acid into a water layer for recovering hydrogen fluoride, rectifying an organic layer by using an upper tower, collecting the 2, 4-dichlorofluorobenzene product in the range of 172-mangnolia officinalis and 174 ℃, then carrying out reduced pressure distillation on the collected material liquid after the 2, 4-dichlorofluorobenzene is finished, and collecting the 136-mangnolia officinalis fraction as the residual raw material 2, 4-dichloroaniline under the vacuum degree of 0.098 MPa.
The mass ratio of the hydrogen fluoride to the reclaimed water in the raw material in the fluorination reaction is 1.2-4: 1.
compared with the prior art, the invention has the beneficial effects that:
(1) according to the synthesis method of the 2, 4-dichlorofluorobenzene, hydrogen fluoride is used as a solvent, 2, 4-dichloroaniline is used as a raw material, and the 2, 4-dichlorofluorobenzene is obtained through direct pressure fluorination, so that the defects that reaction conditions are harsh and high-risk and high-pollution nitroxide tail gas is generated in the original chlorofluoronitrobenzene chlorination route are overcome, the defects that the route is long and three wastes are multiple in the original diazotization route are overcome, the synthesis steps are simple, the raw material source is wide, the generated byproduct ammonium fluoride can be generated into hydrogen fluoride after sulfuric acid recovery treatment and used as the solvent, meanwhile, the generated ammonium sulfate salt can be used as a byproduct, no solid waste liquid is generated in the whole process, the selectivity is high, and the environment is friendly;
(2) according to the synthesis method of the 2, 4-dichlorofluorobenzene, the purity of the prepared product 2, 4-dichlorofluorobenzene is high and can reach 99.48% -99.81%;
(3) the synthesis method of 2, 4-dichlorofluorobenzene has high conversion rate and selectivity, the conversion rate can reach 20.94% -53.27%, and the selectivity can reach 86.19% -96.78%.
Drawings
FIG. 1 shows the reaction process of 2, 4-dichlorofluorobenzene synthesis.
Detailed Description
In order to more clearly understand the technical features, objects, and effects of the present invention, specific embodiments of the present invention will now be described.
The conversion in the examples is calculated as: 1- (mass of residual 2, 4-dichloroaniline/mass of initial 2, 4-dichloroaniline);
the calculation formula of selectivity is: [ mass of 2, 4-dichlorofluorobenzene as a product/relative molecular weight of 2, 4-dichlorofluorobenzene/(mass of 2, 4-dichloroaniline as a starting material/molecular weight of 2, 4-dichloroaniline as a starting material) ]/conversion.
Example 1
As shown in fig. 1, a method for synthesizing 2, 4-dichlorofluorobenzene specifically comprises the following steps:
1. fluorination reaction: adding 162g of initial raw material 2, 4-dichloroaniline into a high-pressure reaction kettle, adding 0.48g of water, then filling 100g of hydrogen fluoride into the high-pressure reaction kettle in an ice bath, tightening a kettle cover, slowly heating the reaction kettle to 153 ℃ for timing, controlling the temperature rise time to be 1h, keeping the reaction temperature at 153 ℃ for 12h, cooling to 50 ℃, opening a valve to release redundant hydrogen fluoride, cooling, liquefying, and reusing as a reaction.
2. Raw material recovery: then adding 50g of water into the residual feed liquid for dissolving and layering, separating a water outlet layer, dropwise adding sulfuric acid into a water layer for recovering hydrogen fluoride, performing upper-tower rectification on an organic layer, collecting the 2, 4-dichlorofluorobenzene product at the temperature of 172-174 ℃, collecting 33.44g of the product with the purity of 99.51%; then, the liquid after collecting the 2, 4-dichlorofluorobenzene is subjected to reduced pressure distillation, and the 134-dichloroaniline with the temperature of 136 ℃ as the residual raw material is collected under the vacuum degree of 0.098MPa, and 128.08g is collected. The conversion was calculated to be 20.94% and the selectivity 96.78%.
Example 2
The difference between the example and the example 1 is that the reaction temperature of the fluorination reaction is 168 ℃, the pressure of the reaction kettle is 4.5MPa after the temperature is raised to 168 ℃, 49.73g of the product 2, 4-dichlorofluorobenzene is obtained, the purity is 99.61%, 111.34g of the raw material 2, 4-dichloroaniline is obtained, the conversion rate is 31.27%, and the selectivity is 96.39%.
Example 3
The difference between the example and the example 1 is that the reaction temperature of the fluorination reaction is 178 ℃, the pressure of the reaction kettle is 5.0MPa after the temperature is raised to 178 ℃, 63.02g of the product 2, 4-dichlorofluorobenzene is obtained, the purity is 99.52 percent, 97.44g of the raw material 2, 4-dichloroaniline is obtained, the conversion rate is 39.85 percent, and the selectivity is 95.84 percent.
Example 4
The difference between the example and the example 1 is that the reaction temperature of the fluorination reaction is 188 ℃, the pressure of the reaction kettle is 6.3MPa after the temperature is raised to 188 ℃, 79.94g of 2, 4-dichlorofluorobenzene is obtained, the purity is 99.48%, 80.42g of raw material 2, 4-dichloroaniline is obtained, the conversion rate is 50.36%, and the selectivity is 96.21%.
Example 5
The difference between the example and the example 1 is that the reaction temperature of the fluorination reaction is 198 ℃, the pressure of the reaction kettle is 7.9MPa after the temperature is raised to 198 ℃, 81.15g of the product 2, 4-dichlorofluorobenzene is obtained, the purity is 99.53 percent, 75.83g of the raw material 2, 4-dichloroaniline is obtained, the conversion rate is 53.19 percent, and the selectivity is 92.46 percent.
As can be seen from examples 1-5, the conversion rate is too low when the holding temperature is low, and the conversion rate is slightly increased when the holding temperature is too high, but the selectivity is obviously decreased, and the holding temperature is preferably 188 ℃.
Example 6
This example is different from example 4 in that the amount of hydrogen fluoride introduced in the fluorination reaction was 120g, and 81.22g of 2, 4-dichlorofluorobenzene was obtained as a product with a purity of 99.67%, 79.25g of 2, 4-dichloroaniline as a starting material was obtained, the conversion was 51.08%, and the selectivity was 96.37%.
Example 7
This example is different from example 4 in that the amount of hydrogen fluoride introduced in the fluorination reaction was 60g, and 60.88g of 2, 4-dichlorofluorobenzene was obtained as a product with a purity of 99.81%, 92.65g of 2, 4-dichloroaniline as a starting material was obtained, the conversion was 42.81%, and the selectivity was 86.19%.
Example 8
This example is different from example 4 in that the amount of hydrogen fluoride introduced in the fluorination reaction was 150g, and 83.39g of 2, 4-dichlorofluorobenzene was obtained as a product with a purity of 99.75%, and 76.37g of 2, 4-dichloroaniline as a starting material was obtained with a conversion of 52.86% and a selectivity of 95.61%.
Example 9
This example is different from example 4 in that the amount of hydrogen fluoride introduced in the fluorination reaction was 200g, and 83.00g of 2, 4-dichlorofluorobenzene was obtained as a product with a purity of 99.61%, 75.70g of 2, 4-dichloroaniline as a starting material was obtained, the conversion rate was 53.27%, and the selectivity was 94.43%.
For the present reaction, theoretically, the amount of hydrogen fluoride used is more than 2eq (equivalent), i.e., more than 2mol of hydrogen fluoride is consumed by 1mol of the starting material, 2, 4-dichloroaniline.
It can also be seen from examples 4, 6, 7, 8 and 9 that when the amount of hydrogen fluoride is small, the conversion is low and the selectivity is low, and other by-products are generated, but when the amount of hydrogen fluoride is greater than 5eq, the conversion is slightly increased, but the selectivity is slightly decreased, and considering the recycling cost of 2, 4-dichloroaniline as a raw material and the recovery cost of hydrogen fluoride, it is appropriate to select 5eq for hydrogen fluoride.
Example 10
This example is different from example 4 in that 0.16g of water was added in the fluorination reaction to obtain 64.17g of 2, 4-dichlorofluorobenzene as a product with a purity of 99.79%, 96.65g of the starting material 2, 4-dichloroaniline with a conversion of 40.34% and a selectivity of 96.41%.
Example 11
This example is different from example 4 in that 0.32g of water was added in the fluorination reaction to obtain 77.00g of 2, 4-dichlorofluorobenzene as a product with a purity of 99.59% and 83.40g of raw material 2, 4-dichloroaniline with a conversion of 48.52% and a selectivity of 96.18%.
Example 12
This example is different from example 4 in that 0.65g of water was added in the fluorination reaction to obtain 79.22g of 2, 4-dichlorofluorobenzene as a product with a purity of 99.64% and 79.53g of raw material 2, 4-dichloroaniline with a conversion of 50.51% and a selectivity of 94.31%.
Example 13
This example is different from example 4 in that 0.82g of water was added in the fluorination reaction to obtain 76.46g of 2, 4-dichlorofluorobenzene having a purity of 99.73% as a starting material, 78.34g of 2, 4-dichloroaniline, a conversion of 51.64% and a selectivity of 89.73%.
From examples 4 and 10 to 13, it is understood that the amount of water used has a significant influence on the conversion, that the conversion is low when the mass ratio of water to the raw material (i.e., 2, 4-dichloroaniline) is 0.2% or less, and that the conversion is substantially stable and slightly increased when the mass ratio of water to the raw material (i.e., 2, 4-dichloroaniline) is 0.3% or more, but the increase in the water content is accompanied by a slight decrease in the selectivity, and that it is preferable to select the water content of 0.2 to 0.3% from the viewpoint of the conversion and the utilization of hydrogen fluoride.
All percentages used in the present invention are mass percentages unless otherwise indicated.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. The synthesis method of 2, 4-dichlorofluorobenzene is characterized by comprising a fluorination reaction and raw material recovery;
the fluorination reaction comprises the steps of adding 2, 4-dichloroaniline and water into a reaction kettle, then adding hydrogen fluoride in an ice bath, then closing the reaction kettle, slowly heating to the reaction temperature of 153-198 ℃, controlling the heating time to be 1h, then keeping the temperature for 12h, cooling to 50 ℃, releasing redundant hydrogen fluoride, cooling and liquefying the hydrogen fluoride, and then reusing the hydrogen fluoride as a reaction;
the raw material recovery, adding water to the residual material liquid for dissolving and layering, separating a water outlet layer, then dropwise adding sulfuric acid to a water layer for recovering hydrogen fluoride, performing upper-tower rectification on an organic layer, collecting 2, 4-dichlorofluorobenzene serving as a product in a range of 172-dichlorofluorobenzene and 174 ℃, then performing reduced pressure distillation on the collected material liquid after the 2, 4-dichlorofluorobenzene is finished, and collecting a fraction of 134-136 ℃ serving as the residual raw material 2, 4-dichloroaniline under the vacuum degree of 0.098 MPa;
the molar ratio of the 2, 4-dichloroaniline to the hydrogen fluoride in the fluorination reaction is 1: 3-10;
the mass ratio of water to 2, 4-dichloroaniline in the fluorination reaction is 0.1-0.5: 100.
2. The method for synthesizing 2, 4-dichlorofluorobenzene according to claim 1, wherein the mass ratio of hydrogen fluoride to water in raw material recovery in the fluorination reaction is 1.2-4: 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111536018.XA CN113929553B (en) | 2021-12-16 | 2021-12-16 | Synthetic method of 2, 4-dichlorofluorobenzene |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111536018.XA CN113929553B (en) | 2021-12-16 | 2021-12-16 | Synthetic method of 2, 4-dichlorofluorobenzene |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113929553A CN113929553A (en) | 2022-01-14 |
| CN113929553B true CN113929553B (en) | 2022-03-25 |
Family
ID=79289032
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111536018.XA Active CN113929553B (en) | 2021-12-16 | 2021-12-16 | Synthetic method of 2, 4-dichlorofluorobenzene |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113929553B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116063143B (en) * | 2023-01-28 | 2023-06-09 | 山东国邦药业有限公司 | Preparation method of 2, 4-dichloro fluorobenzene |
| CN116730795B (en) * | 2023-08-11 | 2023-10-27 | 山东国邦药业有限公司 | Synthesis method of trifluoro-phenylacetic acid intermediate 1,2, 4-trifluoro-benzene |
| CN117384004B (en) * | 2023-12-11 | 2024-03-29 | 山东国邦药业有限公司 | Synthesis method of 2, 4-dichloro fluorobenzene |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3142856A1 (en) * | 1981-10-29 | 1983-05-11 | Bayer Ag, 5090 Leverkusen | METHOD FOR PRODUCING 2,4-DICHLOR-5-FLUOR-BENZOYL CHLORIDE |
| CN101134712A (en) * | 2007-10-08 | 2008-03-05 | 浙江省常山长盛化工有限公司 | Preparation method of 2,4-dichloro fluorobenzene |
| CN101289396A (en) * | 2008-05-30 | 2008-10-22 | 浙江富盛控股集团有限公司 | Process for separating and utilizing mixing components of o-, m-, and p-nitrochlorobenzene |
| CN101613286A (en) * | 2009-07-17 | 2009-12-30 | 淮安嘉诚高新化工股份有限公司 | The separation of nitrobenzene chlorides and method of comprehensive utilization |
| CN108250035A (en) * | 2018-02-26 | 2018-07-06 | 响水新联合化学有限公司 | One kind is used for fluorobenzene processing unit (plant) |
| CN108821939A (en) * | 2018-08-06 | 2018-11-16 | 江苏沙星化工有限公司 | A kind of synthetic method of Ciprofloxacin intermediate 2,4 dichloro fluorobenzene |
-
2021
- 2021-12-16 CN CN202111536018.XA patent/CN113929553B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN113929553A (en) | 2022-01-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113929553B (en) | Synthetic method of 2, 4-dichlorofluorobenzene | |
| CN110498730B (en) | Synthetic method of 1,2, 4-trifluorobenzene | |
| CN112010733B (en) | Preparation method of 3,4, 5-trifluorobromobenzene | |
| CN102911008A (en) | Trichloro ethylene preparation method | |
| CN104262081A (en) | Method utilizing gas-phase hexachloro-1,3-butadiene to prepare hexachloroethane | |
| CN111269082A (en) | Preparation method of 3, 5-dimethyl fluorobenzene | |
| CN110804001A (en) | Production method of 3, 4-difluorobenzonitrile process | |
| CN107641067B (en) | Alpha-bromination method of o-diketone | |
| JP2013177331A (en) | Method for recovering triethylamine and acetone from waste liquid produced in manufacture of naphthalenedicarboxylic acid | |
| WO2022105230A1 (en) | Method for co-producing 1,1-difluoroethane and vinyl chloride | |
| CN112608213B (en) | Method for preparing 1, 1-difluoroethane in gas phase | |
| CN108530301A (en) | A kind of synthetic method of tri- fluorin benzyl amines of 2,4,6- | |
| CN1258519C (en) | Method for co-production of 3-chloro-4-fluoroaniline and 2, 6-dichlorofluorobenzene | |
| CN114315785A (en) | Method for preparing fluoroethylene carbonate by continuous gas-phase fluorine-chlorine exchange of fixed bed | |
| CN102807487A (en) | Synthetic method of onglyza intermediate | |
| CN109912423B (en) | Green synthesis process of 3, 5-dinitro-4-methylbenzoic acid | |
| CN112661626A (en) | Method for preparing 2,4, 6-trimethyl benzoic acid from mesitylene and carbon dioxide | |
| CN106631651A (en) | Preparation method of benzyl methylbenzene | |
| CN112479824A (en) | Method for recovering crystallization mother liquor in production process of 4-chloro-3, 5-dimethylphenol | |
| CN108947849A (en) | A kind of method of solvent-free catalytic hydrogenation production 2,4 difluorobenzene amine | |
| CN116283597B (en) | Preparation method of color photographic paper raw material 2,3, 5-trichloro-4-ethylnitrobenzene | |
| CN101643419A (en) | Method for preparing o-nitroanisole | |
| JP3836541B2 (en) | Method for producing 4,4'-bis (chloromethyl) biphenyl | |
| CN112457197B (en) | Preparation method of compound 2, 4, 6-trifluorobenzylamine | |
| JP2008247850A (en) | Method for producing tetracyclododecene |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |