Preparation method of methomyl

A technology of methomyl and methylthioacetaldoxime, which is applied in the field of methomyl preparation, can solve problems such as equipment blockage, increased cost and difficulty of three waste treatment, and influence on normal production of the workshop

Active Publication Date: 2020-07-07
湖南海利常德农药化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The yield of this method has increased, but the microporous filtration process is likely to cause equipment blockage and affect the normal production of the workshop
In addition, adding a large amount of industrial salt to the mother liquor or reaction liquid increases the production cost and also increases the cost and difficulty of the three wastes treatment

Method used

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  • Preparation method of methomyl

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Experimental program
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Effect test

Embodiment 1

[0027] A preparation method of methomyl of the present invention comprises the following steps:

[0028] Add 107.16g (98.13%, 1mol) methylthioacetaldoxime, 0.33g (99%, 0.001mol) tetrabutylammonium bromide and 214.32g water to a 1000mL three-necked flask successively, drop 58.39g after cooling to 15°C (99.64%, 1.02mol) methyl isocyanate, after the dropwise addition, keep warm for 0.5h. After the reaction is completed, the temperature is raised to 50-60°C, the material is completely dissolved, cooled and crystallized, filtered, the filtrate is extracted with 85.73g of dichloromethane, and then precipitated, the precipitated solid is combined with the filter cake, and then dried in a vacuum oven at 50°C After drying for 12 hours, 160.56 g of white crystalline methomyl product was obtained, with a content of 98.5% and a yield of 97.5%.

Embodiment 2

[0030] A preparation method of methomyl of the present invention comprises the following steps:

[0031] Add 107.16g (98.13%, 1mol) methylthioglyoxaldoxime, 1.42g (98%, 0.005mol) tetrabutylammonium chloride and 321.48g water successively into a 1000mL three-necked flask, drop the temperature to 25°C and add 59.54g (99.64%, 1.04mol) methyl isocyanate, after the dropwise addition, keep warm for 1 hour. After the reaction was completed, the temperature was raised to 50-60°C, the material was completely dissolved, cooled and crystallized, filtered, the filtrate was extracted with 53.58g of chloroform, the precipitated solid was combined with the filter cake, and then dried in a vacuum oven at 50°C for 12 hours to obtain 161.37g white crystal methomyl product, content 98.21%, yield 97.7%.

Embodiment 3

[0033] A preparation method of methomyl of the present invention comprises the following steps:

[0034] Add 107.16g (98.13%, 1mol) methylthioacetaldoxime, 0.17g (99%, 0.0005mol) tetrabutylammonium bisulfate and 428.64g water in turn to a 1000mL three-necked flask, drop the temperature to 18°C ​​and add 60.68g (99.64%, 1.06mol) methyl isocyanate, after the dropwise addition, keep warm for 0.5h. After the reaction, heat up to 50-60°C, cool and crystallize the material after complete dissolution, filter, extract the filtrate with 107.16g of methyl isobutyl ketone, combine the precipitated solid with the filter cake, and then dry it at 50°C in a vacuum drying oven After 12 hours, 162.71 g of white crystal methomyl product was obtained, with a content of 98% and a yield of 98.3%.

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Abstract

The invention discloses a preparation method of methomyl. Methylthio acetaldoxime is used as a raw material and reacts with methyl isocyanate in water under the action of a phase transfer catalyst, the temperature is raised to 50-60 DEG C after the reaction is finished, cooling crystallization and filtration are performed after the material is completely dissolved, filtrate and a filter cake are obtained, the filtrate is extracted with an organic solvent, desolvation is then carried out, desolventized solids and the filter cake are combined and dried, and a methomyl product is obtained. The preparation method has the advantages of high yield, low cost, simplicity and convenience in operation and the like.

Description

technical field [0001] The invention relates to the technical field of organic chemical industry, in particular to a preparation method of methomyl. Background technique [0002] Methomyl is an oxime carbamate insecticide, acaricide, nematocide and molluscicide, developed by DuPont Company of the United States in 1966, with contact killing, stomach poisoning and ovicidal effects, and strong lethality , quick effect, wide insecticidal spectrum, low residue, wide range of crops, safe to use, widely used in cotton, cabbage, tobacco, citrus, soybeans, peanuts and more than 30 kinds of crops. Methomyl is a highly toxic pesticide and will be banned soon, but it can still be used as an important intermediate for the synthesis of thiodimethomyl. Thiodicarb, English common name thiodicarb, also known as Lavein, is a second-generation carbamate insecticide, which is one of the low-toxicity derivatives further improved on the basis of methomyl , that is, two methomyl molecules are co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C327/58
CPCC07C327/58
Inventor 罗先福刘国文臧阳陵杜升华尹霖刘卫东
Owner 湖南海利常德农药化工有限公司
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