Method for synthesizing thiodicarb with high methomyl conversion rate

A technology of high methomyl conversion rate and synthesis method, applied in the field of thiodicarb synthesis with high methomyl conversion rate, to achieve the effects of increasing reaction temperature, reducing side reactions and improving yield

Active Publication Date: 2022-04-12
SHANDONG FIRST MEDICAL UNIV & SHANDONG ACADEMY OF MEDICAL SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] For the existing problems of using methomyl as the main raw material to produce thiodicarb, the present invention makes an in-depth discussion on its production process on the basis of comparative analysis of existing related processes, and mainly solves the following problems:

Method used

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  • Method for synthesizing thiodicarb with high methomyl conversion rate
  • Method for synthesizing thiodicarb with high methomyl conversion rate
  • Method for synthesizing thiodicarb with high methomyl conversion rate

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preparation example Construction

[0055] The invention provides a method for synthesizing thiodicarb with a high conversion rate of methomyl, comprising the steps of:

[0056] Step 1. Preparation of materials: Add xylene, toluene, and pyridine to the synthesis kettle, start stirring, and feed frozen brine into the jacket of the synthesis kettle at the same time; add SCl 2 The liquid is added to the high level tank after metering;

[0057] Step 2. Reaction: observe the temperature change of the synthesis kettle, and start adding SCl dropwise when the temperature in the synthesis kettle drops to -4-0°C 2 , the dropping time is controlled at 40-60 minutes, SCl 2 Control the reaction temperature not higher than 10°C when adding dropwise; SCl 2 After the dropwise addition, continue to stir for 15-30 minutes, add methomyl to the synthesis kettle at one time, feed nitrogen into the kettle until the pressure in the kettle reaches 0.3-0.35MPa, start to heat up, and start timing when the temperature of the kettle reac...

Embodiment 1

[0067] 1. Measure 1010Kg of xylene, 45Kg of toluene and 300Kg of pyridine into the synthesis kettle, start stirring, and at the same time feed frozen brine into the jacket of the synthesis kettle; use a ribbon stirrer in the synthesis kettle; 2 Add 155Kg to the high level tank after weighing;

[0068] 2. When the temperature in the kettle drops to -4°C, start adding SCl dropwise 2 , adding time 45 minutes, SCl 2 During the dropwise addition, the reaction temperature was controlled at 9°C. SCl 2 After the dropwise addition, continue to stir for 25 minutes and then add 450Kg of methomyl to the synthesis kettle at one time, feed nitrogen into the kettle until the pressure in the kettle reaches 0.3MPa, start to heat up, and start timing since the temperature of the kettle reaches 35°C. Reaction at high temperature for 2.5 hours;

[0069] After the reaction is over, use a pump to send the materials in the synthesis tank to the centrifuge. The centrifuge is measured after analy...

Embodiment 2

[0076] 1. Measure 1010Kg of xylene, 45Kg of toluene and 310Kg of pyridine into the synthesis kettle, start stirring, and at the same time feed frozen brine into the jacket of the synthesis kettle; use a ribbon stirrer in the synthesis kettle; 2 Add 160Kg to the high tank after weighing;

[0077] 2. When the temperature in the kettle drops to -3°C, start adding SCl dropwise 2 , adding time 45 minutes, SCl 2 During the dropwise addition, the reaction temperature was controlled at 8°C. SCl 2 After the dropwise addition, continue to stir for 30 minutes and then add 450Kg of methomyl to the synthesis kettle at one time, feed nitrogen into the kettle until the pressure in the kettle reaches 0.32MPa, start to heat up, and start timing since the temperature of the kettle reaches 37°C, at 32°C Reaction at high temperature for 3 hours;

[0078] After the reaction is over, use a pump to send the materials in the synthesis tank to the centrifuge. The centrifuge is measured after analyz...

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Abstract

The invention relates to a thiodicarb synthesis method with high methomyl conversion rate. The method comprises the following steps: adopting xylene and toluene as solvents; reaction: when the temperature in the synthesis kettle is reduced to be lower than 0 DEG C, starting to dropwise add SCl2, after the SCl2 is dropwise added, adding methomyl into the synthesis kettle, introducing nitrogen into the kettle, heating, and reacting; after the reaction is finished, centrifuging to obtain centrifugate and a centrifugal filter cake; primary water washing and filter pressing; carrying out secondary washing and centrifugation; washing with methanol, and centrifuging; and carrying out vacuum drying on a filter cake obtained by centrifuging the methanol washing material to obtain a thiodicarb finished product. According to the synthesis method provided by the invention, when the intermediate thiobipyridine hydrochloride is synthesized, a toluene and xylene double-component solvent is adopted, pyridine is used as a raw material and a solvent, and the reasonable material ratio avoids the influence on the reaction process of pyridine and sulfur dichloride due to overhigh solid material concentration in a reaction system; the yield of the thiobipyridine hydrochloride and the conversion rate of methomyl in the subsequent reaction between the thiobipyridine hydrochloride and methomyl are improved.

Description

technical field [0001] The invention relates to the technical field of pesticide compound synthesis, in particular to a method for synthesizing thiodicarb with a high conversion rate of methomyl. Background technique [0002] Thiodicarb (also known as dimethomyl, thiodicarb, lavin), is a generation of high-efficiency, broad-spectrum, low-toxicity, systemic carbamate insecticides, which was released by the United States in 1977 The company and Swiss Ciba-Geiji company developed at the same time, put into production in 1984, so far has been registered in more than 30 countries and regions in the world, with an annual sales volume of thousands of tons. It retains the advantages of methomyl, such as broad spectrum and high efficiency against pests, and overcomes the shortcomings of methomyl, which is highly toxic to higher animals and prone to phytotoxicity to various crops, and greatly improves the safety of natural enemies, crops, human bodies and the environment It is widely...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C381/08C07D213/89
Inventor 张恭孝王忠李颂曹晓群王瑞华孙春辉刘梅熊继光赵萍郭献赢王梦杰潘友金左自昊左梦欣
Owner SHANDONG FIRST MEDICAL UNIV & SHANDONG ACADEMY OF MEDICAL SCI
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