Method for preparing pesticide methomyl

A methomyl and pesticide technology, applied in the field of pesticides, can solve the problems of low chemical synthesis reaction selection and yield, unguaranteed product quality, and poor control of reaction temperature, so as to improve the production site environment, The production is safe and controllable, and the effect of reducing the production of by-products

Inactive Publication Date: 2014-01-22
荆州沙隆达控股有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are many side reactions, the reaction temperature is not easy to control, the reaction time is long, and the product quality cannot be guaranteed
The selection and yield of the chemical synthesis reaction are not high, and the output is not high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Example 1: After methylthioacetaldoxime is beaten with water, according to the mass ratio of methylthioacetaldoxime to methyl isocyanate is 1:1.0, add methylisocyanate dropwise to methylthioacetaldoxime beating liquid Reaction, the reaction temperature is controlled at 5°C, and the reaction time is 1.5h; after the above reaction is completed, add activated carbon to the obtained methomyl mixture, then start to heat up to 50°C until the material is completely dissolved, and enter the crystallization tank to cool down and crystallize after passing through micropore filtration. The crystallization temperature drops from 70°C to 55°C within 45 seconds, and crystals begin to precipitate when entering the transition zone. Control the stirring rate and cooling rate to keep decreasing by about 1°C every 30 minutes. After ℃, enter the filtration process for filtration; put the filtered methomyl mixture into a double-cone dryer to dry, control the jacket water temperature to 65°C,...

Embodiment 2

[0012] Example 2: After methylthioacetaldoxime is beaten with water, according to the mass ratio of methylthioacetaldoxime to methyl isocyanate is 1:1.1, add methylisocyanate dropwise to methylthioacetaldoxime beating liquid Reaction, the reaction temperature is controlled at 10°C, and the reaction time is 2h; after the above reaction is completed, add activated carbon to the obtained methomyl mixture, then start to heat up to 70°C until the material is completely dissolved, and enter the crystallization tank to cool down and crystallize after passing through microporous filtration. The temperature drops from 65°C to 50°C within 60 seconds, and crystals begin to precipitate when entering the transition zone. Control the stirring rate and cooling rate to keep decreasing by about 1°C every 30 minutes. When the temperature drops to 43°C, the crystallization is complete, and the temperature drops to 25°C in 15 seconds. Then enter the filtration process for filtration; put the filte...

Embodiment 3

[0013] Example 3: After methylthioacetaldoxime is beaten with water, according to the mass ratio of methylthioacetaldoxime to methyl isocyanate is 1:1.2, add methylisocyanate dropwise to methylthioacetaldoxime beating liquid Reaction, the reaction temperature is controlled at 15°C, and the reaction time is 2.5h; after the above reaction is completed, add activated carbon to the obtained methomyl mixture, then start to heat up to 70°C until the material is completely dissolved, and enter the crystallization tank to cool down and crystallize after passing through micropore filtration. The crystallization temperature drops from 68°C to 55°C within 60 seconds, and crystals begin to precipitate when entering the transition zone. Control the stirring rate and cooling rate to keep decreasing by about 1°C every 30 minutes. After ℃, enter the filtration process for filtration; put the filtered methomyl mixture into a double-cone dryer to dry, control the jacket water temperature to 65°C...

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PUM

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Abstract

The invention discloses a method for preparing pesticide methomyl. The method comprises the following steps: pulping methylthio acetaldehyde oxi me with water, dripping methyl isocyanate into the pulped methylthio acetaldehyde oxi me solution for reaction according to a mass ratio of the methylthio acetaldehyde oxi me to the methyl isocyanate being 1:(1.0-1.3), controlling the reaction temperature to be 5-15 DEG C and reacting time to be 1.5-3 hours; filtering through micropores, cooling, crystallizing, re-filtering, and drying. The method is convenient to operate, safe and controllable in production, can reduce the generation of side products, improves the yield and the quality, reduces the energy consumption and the production cost, improves the production field environment, further improves the solubility and the safety of the reaction, and reduces the emission of 'the Three Wastes'.

Description

technical field [0001] The invention relates to an insecticide, in particular to a method for preparing the pesticide methomyl. Background technique [0002] Methomyl is a broad-spectrum carbamate insecticide with systemic contact and stomach poisoning. It is suitable for controlling pests such as aphids, moths and cutworms in cotton, tobacco, fruit trees and vegetables. A good alternative to medicinal cotton aphids. Methomyl can also be used as an intermediate of thiodicarb. It is a broad-spectrum, quick-acting insecticide that is effective against aphids, cotton bollworms and other pests. It can be used in crops such as grain, cotton, vegetables, tobacco, and fruits. [0003] The domestic pesticide methomyl reacts with methylthioglycetaldoxime and methyl isocyanate at a temperature of 5°C to directly synthesize the target product. Currently, kettle reactors and batch methods are generally used for production. There are many side reactions, the reaction temperature is not...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C327/58
Inventor 李子平黄刚
Owner 荆州沙隆达控股有限公司
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