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Preparation method of 5-chloro-3-trichloromethyl-1,2,4-thiadiazole

A technology of trichloromethyl and thiadiazole, which is applied in the field of 5-chloro-3-trichloromethyl-1, can solve problems such as low yield and complex production process, and achieve improved product quality and yield and reduced production Cost, reduce the effect of purification and refining process

Inactive Publication Date: 2015-06-03
NANJING QIZHENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of this invention is to provide a kind of preparation method of 5-chloro-3-trichloromethyl-1,2,4-thiadiazole, to solve the low yield in the prior art, and used multiple different solvents, complex production process

Method used

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preparation example Construction

[0031] A preparation method of 5-chloro-3-trichloromethyl-1,2,4-thiadiazole, comprising the following steps:

[0032] Step 1. In the process of synthesizing trichloroacetamidine, in the presence of a solvent and a catalyst, feed ammonia gas into a saturated state in an ice-salt water bath at -15°C, start adding the raw material trichloroacetonitrile dropwise, and control the reaction temperature at -10°C , continue to feed excessive ammonia gas until the end of the dropwise addition, and keep the heat until the conversion rate of the raw material trichloroacetonitrile reaches more than 98%, that is, the remaining raw material trichloroacetonitrile is less than 2%, naturally warming up to room temperature and blowing away the excess by nitrogen bubbling ammonia;

[0033] Step 2: Cool down the reaction solution to -5°C, add liquid alkali dropwise to adjust the pH value to 9, then add trichloromethylsulfonyl chloride dropwise, keep the pH value at 8-9, make the trichloroacetamidi...

Embodiment 1

[0040] Add 350Kg of dichloroethane and 1Kg of tetrabutylammonium bromide into a 500L kettle, turn on the freezer and stir to cool down to -10°C. Infuse ammonia gas to keep 4-5Kg per hour. After the temperature rises to a certain level and then drops to -10°C, start to add 100Kg of trichloroacetonitrile dropwise. The temperature of trichloroacetonitrile is controlled at -10°C and added dropwise within 5 hours Finish. After the dropwise addition, continue to pass the ammonia gas to sample, and control the remaining raw materials to be less than 2%. After the reaction is over, stop the ammonia gas flow, close the cooling valve and open the nitrogen valve to naturally heat up to 20°C

[0041] Transfer the material to a 1000L ring-closure kettle.

[0042] Cool the material in the ring-closing kettle to -5°C and add 30% lye dropwise to make the pH value of the reaction system reach 9, then start to add 135.5Kg of trichloromethylsulfonyl chloride dropwise at the same time, and then ...

Embodiment 2

[0044] Add 350Kg of dichloromethane and 1Kg of triethylbenzyl ammonium chloride into a 500L kettle, turn on the freezer and stir to cool down to -10°C. Infuse ammonia gas to keep 4-5Kg per hour. After the temperature rises to a certain level and then drops to -10°C, start to add 100Kg of trichloroacetonitrile dropwise. The temperature of trichloroacetonitrile is controlled at -10°C and added dropwise within 5 hours Finish. After the dropwise addition, continue to pass the ammonia gas to sample, and control the remaining raw materials to be less than 2%. After the reaction is over, stop the ammonia gas flow, close the cooling valve and open the nitrogen valve to naturally heat up to 20°C

[0045] Transfer the material to a 1000L ring-closure kettle.

[0046] Cool the material in the ring-closing kettle to -5°C and add 30% lye dropwise to make the pH value of the reaction system reach 9, then start to add 135.5Kg of trichloromethylsulfuryl chloride dropwise, and then dropwise a...

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Abstract

The invention discloses a preparation method of 5-chloro-3-trichloromethyl-1,2,4-thiadiazole. The preparation method comprises the following steps: by taking trichloroacetonitrile as a raw material, firstly synthesizing trichloro-acetamidine, and then preparing thiadiazole to achieve continuous reaction. By adopting the preparation method disclosed by the invention, separation processes of an intermediate trichloro-acetamidine can be reduced; a single solvent is used in the whole reaction so as to ensure that continuous production of two-step reaction can be achieved; a liquid ammonia mode is changed into a production mode of introducing ammonia gas into the solvent, and the reaction temperature is improved to adapt to the industrial production; the trichloro-acetamidine intermediate does not need to be treated additionally, and can be directly applied to the next reaction to ensure that purification and refining processes can be reduced; the quality and yield of products can be significantly improved, and the production cost can be reduced; and greater industrial production values can be achieved.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, in particular to a preparation method of 5-chloro-3-trichloromethyl-1,2,4-thiadiazole. Background technique [0002] 5-Chloro-3-trichloromethyl-1,2,4-thiadiazole (referred to as "thiadiazole") is a very important intermediate in pharmaceutical and pesticide products. [0003] [0004] According to the patent DE671785 and the literature Journal of Medicinal Chemistry, 1978, Vol. 21, No. 12, P1285, the synthesis of trichloroacetamidine was reported. Trichloroacetonitrile was added dropwise to liquid ammonia at a low temperature of -40°C and reacted for 7 hours to drive off the residual ammonia. Then add benzene, filter and concentrate, and the yield of recrystallization with hexane is only 52%. Add the hydrogen chloride solution of ethanol dropwise to the ethyl acetate solution to prepare trichloroacetamidine hydrochloride. The reaction needs to be carried out under the cooling conditions of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D285/08
CPCC07D285/08
Inventor 车鈜席亚男钟奇军
Owner NANJING QIZHENG CHEM
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