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A kind of synthetic technique of oxadiazone

A synthesis process and technology of oxadiazon, applied in the field of organic compound synthesis, can solve problems such as phosgene poisoning, and achieve the effect of avoiding potential safety hazards and high safety

Active Publication Date: 2016-08-31
HEFEI XINGYU CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It can be seen that in the process of synthesizing oxadiazone with hydrazide as the key intermediate, if phosgene or triphosgene is used as the carbonylation ring-closing reagent, phosgene poisoning accidents are prone to occur, and there is a large safety hazard

Method used

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  • A kind of synthetic technique of oxadiazone
  • A kind of synthetic technique of oxadiazone
  • A kind of synthetic technique of oxadiazone

Examples

Experimental program
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Effect test

Embodiment 1

[0044]Add 5.0Kmol of 2,4-dichloro-5-isopropoxyphenylhydrazide and an appropriate amount of toluene solution into the reaction kettle, stir and dissolve, slowly add 5.3Kmol of methyl chloroformate solution dropwise, and the dropwise addition is completed within 2 hours. Insulate for 2 hours, slowly raise the temperature to reflux, reflux for 3 hours, take a sample to detect that the residual hydrazide is 0.1%, which is regarded as the end of the reaction, add catalyst anhydrous sodium methoxide 0.05Kmol, keep the temperature at 90-110°C for 6 hours, and the by-product methanol After the reaction is completed, the temperature is lowered, washed with water, crystallized, and dried to obtain 1712.2 kg of the oxadiazone product. It is detected by gas chromatography. Under the same chromatographic operating conditions, the sample is dissolved in chloroform, and tetradecane is used as an internal standard. figure 1 It is the gas chromatogram of oxadiazone standard sample, wherein the...

Embodiment 2

[0046] Add 5.0Kmol of 2,4-dichloro-5-isopropoxyphenylhydrazide and an appropriate amount of dichloroethane solution into the reaction kettle, stir and dissolve, and slowly add 6.0Kmol of methyl chloroformate solution dropwise in 2 hours, After 1.5 hours of dropwise addition, keep warm for 1.5 hours, slowly raise the temperature to reflux, and reflux for 5 hours. Sampling and detection of hydrazide is 0, and the reaction is complete. Add catalyst anhydrous sodium acetate 0.2Kmol, and keep warm at 60-70°C for 4 hours. During the reaction, the The by-product methanol was released, and after the reaction was completed, the temperature was lowered, washed with water, crystallized, and dried to obtain 1695.4 kg of oxadiazone product. It is detected by gas chromatography. Under the same chromatographic operating conditions, the sample is dissolved in chloroform, and tetradecane is used as an internal standard. figure 1 It is the gas chromatogram of oxadiazone standard sample, wherein...

Embodiment 3

[0048] Add 2.0Kmol of 2,4-dichloro-5-isopropoxyphenylhydrazide and an appropriate amount of dichlorobenzene solution into the reaction kettle, stir to dissolve, slowly add the metered methyl chloroformate solution 3Kmol dropwise, and complete the dropwise addition within 1 hour , keep warm for 1h, slowly raise the temperature to reflux, reflux for 0.5h, take a sample to detect that the residual hydrazide is more than 0.5%, continue the reflux reaction for 1h, take a sample to detect that the residual hydrazide is 0.2%, regard it as the end of the reaction, add the crushed catalyst sodium hydroxide 0.1Kmol, heat up to 180-200°C and keep it warm for 3 hours. During the reaction, the by-product methanol is released. After the reaction, the temperature is lowered, washed with water, crystallized, and dried to obtain 685.3kg of oxadiazone product. It is detected by gas chromatography. Under the same chromatographic operating conditions, the sample is dissolved in chloroform, and tet...

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Abstract

The invention discloses a synthesis technology of oxadiazon. The synthesis technology comprises following steps: (A). carrying out a reaction between 2,4-dichloro-5-isopropoxylbenzhydrazide and methyl chloroformate in an organic solvent to obtain hydrazide methyl ester; (B). enabling the hydrazide methyl ester to be subjected to a cyclization reaction under the effect of a catalyst to obtain the oxadiazon. During the synthesis technology of the oxadiazon, the oxadiazon is synthesized with 2,4-dichloro-5-isopropoxylbenzhydrazide and methyl chloroformate being raw materials, wherein the methyl chloroformate is employed, instead of phosgene or triphosgene, as a carbonylation ring-closing reagent, so that safety potential risk during a conventional phosgene technology is avoided, which enables the synthesis technology of the oxadiazon to be high in safety. In addition, yield of the oxadiazon is high in the invention. An experimental result proves that the yield of the oxadiazon is higher than 97%.

Description

technical field [0001] The invention relates to the technical field of organic compound synthesis, in particular to a synthesis process of oxadiazone. Background technique [0002] Oxadiazon, also known as oxadiazon, is an organic heterocyclic contact type pre-emergent herbicide, mainly used for weeding in paddy fields, and also effective for peanuts, cotton, sugarcane, etc. in dry fields. Oxadiazone is popular among users for its advantages of wide herbicidal spectrum, high efficiency, low toxicity, less dosage, low residue, no impact on subsequent crops, good ecological benefits and convenient use. [0003] At present, oxadiazone at home and abroad is prepared by cyclization reaction of one of phosgene and triphosgene with 2,4-dichloro-5-isopropoxyphenylhydrazide, wherein 2,4-dichloro-5 -Isopropoxyphenylhydrazide (hydrazide for short) is used as a key intermediate, and phosgene or triphosgene is used as a carbonylation ring-closing reagent. [0004] In the preparation pr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D271/113
CPCC07D271/113
Inventor 何普泉王龙王兰兰王传品徐文军雷世超秦震霓
Owner HEFEI XINGYU CHEM
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