CN102702087A - Method for synthesizing 2, 3-difluoro-5-chloropyridine - Google Patents
Method for synthesizing 2, 3-difluoro-5-chloropyridine Download PDFInfo
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- CN102702087A CN102702087A CN2012101761373A CN201210176137A CN102702087A CN 102702087 A CN102702087 A CN 102702087A CN 2012101761373 A CN2012101761373 A CN 2012101761373A CN 201210176137 A CN201210176137 A CN 201210176137A CN 102702087 A CN102702087 A CN 102702087A
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- chloropyridine
- difluoro
- trichloropyridine
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Abstract
The invention relates to a method for synthesizing 2, 3-difluoro-5-chloropyridine. The method comprises the following steps of: performing heat preservation reaction by taking 2,3,5-trichloropyridine and anhydrous potassium fluoride as raw materials at the temperature of between 200 and 210 DEG C in the presence of a catalyst under the protection of inert gases for 10 to 20 hours in an organic solvent, continuing rectifying under reduced pressure to obtain a crude product, and rectifying the crude product to obtain a finished product. The method is characterized in that the catalyst is N-bis(dimethylamino)methylene-1,3-dimethyl tetrahydroglyoxaline-2-imine chloride. According to the method, a process is simple, mild in reaction, short in period and high in yield.
Description
Technical field
The invention belongs to chemical field, be specifically related to a kind of 2, the compound method of 3-difluoro-5-chloropyridine.
Background technology
2, the 3-difluoro-5-chloropyridine is the indispensable midbody of chirality, efficient, low toxicity, broad-spectrum herbicide alkynes grass ester, and this weedicide can be prevented and treated cotton, rape, soybean effectively, in the wheat paddock weeds, has broad application prospects especially.
Reference of the present invention all is Synthetic 2s, the related patent U.S. Patent No. of 3-difluoro-5-chloropyridine, and they are with 2,3, the 5-trichloropyridine is main starting raw material Synthetic 2 with containing villiaumite, the 3-difluoro-5-chloropyridine.Chinese patent (publication number is CN1830963A) content relates to 2,3, and 5-trichloropyridine and Potassium monofluoride, cesium fluoride are starting raw material, are solvent with the solion, in the presence of catalyzer, make 2, the 3-difluoro-5-chloropyridine.Chinese patent (publication number is CN101648904A) content relates to 2,3, and 5-trichloropyridine and Potassium monofluoride are starting raw material, are solvent with the tetramethylene sulfone, are in the presence of the catalyzer at Tetraphenylphosphonium Bromide, make 2, the 3-difluoro-5-chloropyridine.
All above-mentioned haloid reactions not only need be used the higher cesium fluoride of price, and yield has only about 30% at most.
Summary of the invention
It is low to the purpose of this invention is to provide a kind of preparation cost, yield high 2, the compound method of 3-difluoro-5-chloropyridine.
The objective of the invention is to realize through following technical scheme: a kind of 2, the compound method of 3-difluoro-5-chloropyridine, this method is in organic solvent; With 2,3,5-trichloropyridine and anhydrous potassium fluoride were raw material under catalyzer existed; Under protection of inert gas, 200 ~ 210 ℃ of insulation reaction continued rectification under vacuum and get bullion after 10 ~ 20 hours; Bullion gets finished product through rectifying again, it is characterized in that said catalyzer is two (dimethylin) methylene radical of N--1.3-methylimidazole quinoline-2-protochloride ammonium salt.
Said 2,3,5-trichloropyridine and anhydrous potassium fluoride molar ratio are 1:2.2 ~ 5.0, and preferred molar ratio is 1:3, and Potassium monofluoride preferably passes through the anhydrous potassium fluoride of spraying drying pyroprocessing.
Said catalyst levels is every mole 2,3, and the 5-trichloropyridine adds 5 ~ 20g catalyzer, and preferred every mole 2,3, the 5-trichloropyridine adds the 10g phase-transfer catalyst.
Said organic solvent is a tetramethylene sulfone, and every mole 2,3, the 5-trichloropyridine adds 5 ~ 10 moles of tetramethylene sulfone, and preferred every mole 2,3, the 5-trichloropyridine adds 8 moles of tetramethylene sulfone.
Reaction and rectification under vacuum combine and carry out synchronously.
Said rare gas element is a nitrogen.
The fluoridation that the present invention adopts belongs to the solid-liquid inhomogeneous reaction, needs phase-transfer catalyst as F
-Ion transmits medium mutually at solid-liquid two, increases F
-The solubleness of ion in liquid phase improves reaction yield; (dimethylin) methylene radical-1.3-methylimidazole quinoline-2-protochloride ammonium salt is a catalyzer to adopt N-pair, and catalytic effect is optimum, this catalyst tolerates high temperature; The use temperature broad; Can bring into play better activity, yield can reach 80%, and the yield of comparing organophosphorus, crown ether and other catalyzer can only reach 30%; Improve yield significantly, reduced preparation cost.
The present invention adopts limit coronite rectifying, removes on the one hand product and impels reaction to carry out, and improves concentration of reactants and accelerates chemical reaction and carry out, and reduces product time at high temperature on the other hand, reduce fall fluorine and pyrogenic maybe, further improve reaction yield.
Of the present invention 2; The compound method of 3-difluoro-5-chloropyridine adopts high reactivity anhydrous potassium fluoride cheap and easy to get as fluorination reagent, and through adding effective catalyst, the method for product is shifted out on the limit of adopting reaction and rectifying to combine; Obtain yield greater than 82% 2; The 3-difluoro-5-chloropyridine had both been avoided expensive fluorination reagents such as cesium fluoride, had also solved and had fluoridized the low shortcoming of yield.Present method is simple to operate, is fit to large-scale industrial production.
Embodiment
According to following instance, can understand the present invention better.Yet, those skilled in the art will readily understand that the described concrete material proportion of embodiment, processing condition and result thereof only are used to explain the present invention, and should also can not limit the present invention that claims are described in detail.
Embodiment 1:
On one liter of ware neck flask, install 60cm rectifying volumn and recirculation control device and electric mixer, and connect vacuum system, 2; 3,5-trichloropyridine 182.5g (1mol), Potassium monofluoride 174g (3mol) are dissolved in 800g (8mol) tetramethylene sulfone, add toluene 150ml, 3g salt of wormwood simultaneously; Add catalyzer 10g, nitrogen protection is sloughed toluene at 110 ~ 150 ℃ earlier; After continuing to be warming up to the reaction 14h between 205 ℃, rectification under vacuum gets bullion 2, the 3-difluoro-5-chloropyridine; And then go rectifying to get finished product, gas chromatographic analysis: content 98.5%, yield reaches 95%.
Embodiment 2:
On one liter of ware neck flask, install 60cm rectifying volumn and recirculation control device and electric mixer, and connect vacuum system, 2; 3,5-trichloropyridine 182.5g (1mol), Potassium monofluoride 127.4g (2.2mol) are dissolved in 500g (5mol) tetramethylene sulfone, add toluene 150ml, 3g salt of wormwood simultaneously; Add catalyzer 5g, nitrogen protection is sloughed toluene at 110 ~ 150 ℃ earlier; After continuing to be warming up to the reaction 10h between 200 ℃, rectification under vacuum gets bullion 2, the 3-difluoro-5-chloropyridine; And then go rectifying to get finished product, gas chromatographic analysis: content 95%, yield reaches 75%.
Embodiment 3:
On one liter of ware neck flask, install 60cm rectifying volumn and recirculation control device and electric mixer, and connect vacuum system, 2; 3,5-trichloropyridine 182.5g (1mol), Potassium monofluoride 289.6g (5mol) are dissolved in 1000g (10mol) tetramethylene sulfone, add toluene 150ml, 3g salt of wormwood simultaneously; Add catalyzer 8g, nitrogen protection is sloughed toluene at 110 ~ 150 ℃ earlier; After continuing to be warming up to the reaction 20h between 210 ℃, rectification under vacuum gets bullion 2, the 3-difluoro-5-chloropyridine; And then go rectifying to get finished product, gas chromatographic analysis: content 97.5%, yield reaches 82%.
Claims (5)
1. one kind 2, the compound method of 3-difluoro-5-chloropyridine, this method is in organic solvent; With 2,3,5-trichloropyridine and anhydrous potassium fluoride were raw material under catalyzer existed; Under protection of inert gas, 200 ~ 210 ℃ of insulation reaction continued rectification under vacuum and get bullion after 10 ~ 20 hours; Bullion gets finished product through rectifying again, it is characterized in that: said catalyzer is two (dimethylin) methylene radical of N--1.3-methylimidazole quinoline-2-protochloride ammonium salt.
2. described a kind of 2 according to right 1, the compound method of 3-difluoro-5-chloropyridine is characterized in that: said 2,3,5-trichloropyridine and anhydrous potassium fluoride molar ratio are 1:2.2 ~ 5.0.
3. described a kind of 2 according to right 1, the compound method of 3-difluoro-5-chloropyridine is characterized in that: said catalyst levels is every mole 2,3, and the 5-trichloropyridine adds 5 ~ 20g catalyzer.
4. described a kind of 2 according to right 1, the compound method of 3-difluoro-5-chloropyridine is characterized in that: said organic solvent is a tetramethylene sulfone; Every mole 2,3, the 5-trichloropyridine adds 5 ~ 10 moles of tetramethylene sulfone; Preferred every mole 2,3, the 5-trichloropyridine adds 8 moles of tetramethylene sulfone.
5. described a kind of 2 according to right 1, the compound method of 3-difluoro-5-chloropyridine is characterized in that: reaction and rectification under vacuum combine and carry out synchronously.
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| CN2012101761373A CN102702087A (en) | 2012-05-31 | 2012-05-31 | Method for synthesizing 2, 3-difluoro-5-chloropyridine |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103396357A (en) * | 2013-07-29 | 2013-11-20 | 江苏恒安化工有限公司 | Preparation method of 2,3-difluoro-5-chloropyridine |
| CN110845414A (en) * | 2019-11-27 | 2020-02-28 | 济宁康盛彩虹生物科技有限公司 | Preparation method and application of N-bis (dimethylamino) -1, 3-dimethylimidazoline |
| CN112300062A (en) * | 2020-10-30 | 2021-02-02 | 江苏恒安化工有限公司 | Preparation method of 2, 3-difluoro-5-chloropyridine |
| CN112409209A (en) * | 2020-09-28 | 2021-02-26 | 济宁康盛彩虹生物科技有限公司 | Preparation method and application of N-bis (diphenylamino) methylene-N-bis (dimethylamino) methylene-iminium chloride |
| CN114014801A (en) * | 2021-12-13 | 2022-02-08 | 江苏丰山集团股份有限公司 | Green production process of 2, 3-difluoro-5-chloropyridine with low single impurity content |
| CN115108971A (en) * | 2022-06-30 | 2022-09-27 | 杭州凯氟科技有限公司 | Preparation method of 2, 3-difluoro-5-chloropyridine |
Citations (1)
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| CN101671217A (en) * | 2009-09-28 | 2010-03-17 | 南京第一农药集团有限公司 | Method for preparing organic chlorofluoro compounds from organic polychlorinated compounds |
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2012
- 2012-05-31 CN CN2012101761373A patent/CN102702087A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101671217A (en) * | 2009-09-28 | 2010-03-17 | 南京第一农药集团有限公司 | Method for preparing organic chlorofluoro compounds from organic polychlorinated compounds |
Non-Patent Citations (1)
| Title |
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| 沈之芹 等: "氟代苯腈系列化合物的合成研究", 《化学世界》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103396357A (en) * | 2013-07-29 | 2013-11-20 | 江苏恒安化工有限公司 | Preparation method of 2,3-difluoro-5-chloropyridine |
| CN110845414A (en) * | 2019-11-27 | 2020-02-28 | 济宁康盛彩虹生物科技有限公司 | Preparation method and application of N-bis (dimethylamino) -1, 3-dimethylimidazoline |
| WO2021103614A1 (en) * | 2019-11-27 | 2021-06-03 | 济宁康盛彩虹生物科技有限公司 | Preparation method for and use of n-bis(dimethylamino)-1,3-dimethylimidazoline |
| CN112409209A (en) * | 2020-09-28 | 2021-02-26 | 济宁康盛彩虹生物科技有限公司 | Preparation method and application of N-bis (diphenylamino) methylene-N-bis (dimethylamino) methylene-iminium chloride |
| CN112300062A (en) * | 2020-10-30 | 2021-02-02 | 江苏恒安化工有限公司 | Preparation method of 2, 3-difluoro-5-chloropyridine |
| CN114014801A (en) * | 2021-12-13 | 2022-02-08 | 江苏丰山集团股份有限公司 | Green production process of 2, 3-difluoro-5-chloropyridine with low single impurity content |
| CN115108971A (en) * | 2022-06-30 | 2022-09-27 | 杭州凯氟科技有限公司 | Preparation method of 2, 3-difluoro-5-chloropyridine |
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Application publication date: 20121003 |