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Preparation method of 2,3,5,6-tetrachloro-4-methylsulfonylpyridine

A technology for methanesulfonylpyridine and pentachloropyridine, which is applied in the field of preparation of 2,3,5,6-tetrachloro-4-methanesulfonylpyridine, can solve the problem of large odor of intermediates, difficulty in separation and purification, and oxidizing agents. Expensive and other problems, to achieve the effects of less side reactions, cheap and easy-to-obtain raw materials, and improved purity and yield

Active Publication Date: 2021-03-23
LIER CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] In order to solve the problems in the prior art such as difficult product separation and purification, high production cost, large amount of three wastes, relatively strong odor of intermediates, expensive oxidant, etc., the purpose of the present invention is to provide an optimized 2,3,5, The preparation method of 6-tetrachloro-4-methylsulfonylpyridine

Method used

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  • Preparation method of 2,3,5,6-tetrachloro-4-methylsulfonylpyridine
  • Preparation method of 2,3,5,6-tetrachloro-4-methylsulfonylpyridine
  • Preparation method of 2,3,5,6-tetrachloro-4-methylsulfonylpyridine

Examples

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Embodiment 1

[0038] Add 90kg of tetrahydrofuran and 30kg of pentachloropyridine into a 200L enamel reaction kettle, start stirring and slowly add 41.7kg of sodium methyl mercaptide aqueous solution with a mass concentration of 20% at a temperature of 20±5°C, and keep it warm for 1 hour after the addition is completed. , the HPLC control reaction was complete. After phase separation, the organic phase was distilled under normal pressure to recover tetrahydrofuran, then 90 kg of glacial acetic acid and 0.3 kg of catalyst sodium tungstate were added to the organic phase, and 5.7 kg of hydrogen peroxide was added dropwise when the temperature was controlled at 30-40°C. Increase the temperature to 60-75°C and continue to add 5.7kg of hydrogen peroxide dropwise, and finally add 5.7kg of hydrogen peroxide dropwise when the temperature is controlled at 75-85°C. After the reaction in the HPLC control is completed, cool to 20-25°C to crystallize, centrifugally filter, rinse, and dry to obtain 2,3,5,...

Embodiment 2

[0040]Add 90kg of tetrahydrofuran and 30kg of pentachloropyridine into a 200L enamel reaction kettle, start stirring and slowly add 39.8kg of sodium methyl mercaptide with a mass concentration of 22% at a temperature of 20±5°C. After the addition is completed, keep warm for 2 hours. The reaction in the HPLC control was complete. After phase separation, the organic phase was distilled under normal pressure to recover tetrahydrofuran, then 90 kg of glacial acetic acid and 0.3 kg of catalyst sodium tungstate were added to the organic phase, and 5.7 kg of hydrogen peroxide was added dropwise when the temperature was controlled at 30-40°C. Increase the temperature to 60-75°C and continue to add 5.7kg of hydrogen peroxide dropwise, and finally add 5.7kg of hydrogen peroxide dropwise when the temperature is controlled at 75-85°C. After the reaction in the HPLC control is completed, cool to 20-25°C to crystallize, centrifugally filter, rinse, and dry to obtain 2,3,5,6-tetrachloro-4-me...

Embodiment 3

[0042] Add 90kg of tetrahydrofuran and 30kg of pentachloropyridine into a 200L enamel reaction kettle, start stirring and slowly add 39.8kg of sodium methyl mercaptide with a mass concentration of 22% at a temperature of 20±5°C, and keep the temperature for 3 hours after the addition is completed. The reaction in the HPLC control was complete. After phase separation, the organic phase was distilled under normal pressure to recover tetrahydrofuran, then 90 kg of 80% formic acid and 0.3 kg of catalyst sodium tungstate were added to the organic phase, and 6.27 kg of hydrogen peroxide was added dropwise when the temperature was controlled at 30-40°C. Heat up to 60-75°C and continue to add 6.27kg of hydrogen peroxide dropwise. Finally, when the temperature is controlled at 75-85°C, add 6.27kg of hydrogen peroxide dropwise. 29.9kg of 2,3,5,6-tetrachloro-4-methanesulfonylpyridine, the content is 97.5%, and the yield is 85%.

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Abstract

The invention discloses a preparation method of 2,3,5,6-tetrachloro-4-methylsulfonyl pyridine. The preparation method comprises the following steps: dissolving pentachloropyridine in tetrahydrofuran,dropwise adding an aqueous solution of sodium methyl mercaptide at a normal temperature, and separating phases and carrying out atmospheric distillation after reaction to recover tetrahydrofuran to obtain an organic phase; and adding organic acid and a catalyst into the organic phase, dropwise adding hydrogen peroxide in stages, and carrying out cooling and crystallization after reaction to obtainthe target product 2,3,5,6-tetrachloro-4-methylsulfonyl pyridine. According to the preparation method provided by the invention, the problems of difficult product separation and purification, high production cost, large amount of three wastes, large foul smell of intermediates, expensive oxidant and the like in the prior art are solved; an green oxidant is adopted, so that secondary pollution tothe environment is not caused; the reaction conditions are optimized, so that the purity and the yield of the target product are effectively improved; moreover, oxidant raw materials are cheap and easy to obtain, the selectivity is good, the side reactions are few, the product yield is high, the reaction conditions are mild and easy to control, and the process operation is simple and easy to industrialize.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, more specifically, to a preparation method of 2,3,5,6-tetrachloro-4-methanesulfonylpyridine. Background technique [0002] 2,3,5,6-Tetrachloro-4-methanesulfonylpyridine has the characteristics of pyridine pesticides, low solubility in water and moderate solubility in organic solvents, especially used to prevent mold damage to crops. It is also widely used in the fields of ink, paper, textile and polymer materials. [0003] The current method for synthesizing 2,3,5,6-tetrachloro-4-methanesulfonylpyridine is as follows: [0004] [0005] The traditional 2,3,5,6-tetrachloro-4-methanesulfonylpyridine production process uses pentachloropyridine as a raw material, and uses the highly toxic reagent sodium sulfide to perform a nucleophilic substitution reaction on it to generate a sodium thiolate intermediate Then react with methylating reagents such as iodomethane or dimethyl sulfate to o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/71
CPCC07D213/71
Inventor 晏三军范谦黄强林洪兵王玉华
Owner LIER CHEM CO LTD