- Preparation method of oxadiazon intermediate 2, 4-dichloro-5-isopropoxyphenylhydrazine
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The invention provides a preparation method of a herbicide oxadiazon intermediate 2, 4-dichloro-5-isopropoxy phenylhydrazine, which comprises the following steps: by taking a toluene solution of 2, 4-dichloro-5-isopropoxy aniline as a raw material, stirring to form a salt under an acidic condition, reacting with cyanate at a certain temperature to generate urea, degrading and rearranging by Hofmann in an alkaline environment, filtering, after recovering a solvent at normal pressure, taking 2, 4-dichloro-5-isopropoxy phenylhydrazine as a raw material, adding chloroform for extraction, and obtaining a chloroform solution of the 2, 4-dichloro-5-isopropoxy phenylhydrazine which can be directly used for an acylation process to synthesize the oxadiazon key intermediate 2, 4-dichloro-5-isopropoxy phenylhydrazine. According to the method disclosed by the invention, a complicated tin recovery process caused by reduction of diazonium salt by stannous chloride in a traditional synthesis process is effectively avoided, and generation of a large amount of high-salt wastewater in a recovery section is avoided; on the other hand, alkalization operation is avoided, solid materials are not added, the labor intensity is greatly reduced, and the production efficiency is effectively improved.
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Paragraph 0029; 0031; 0033-0034; 0035; 0037; 0038-0039; 0040
(2021/04/21)
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- Oxadiazon synthesis method
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The invention discloses an oxadiazon synthesis method, wherein 2,4-dichloro-5-nitrophenol and 2-bromopropane are adopted as starting raw materials, and etherification, reduction, diazo reduction, acylation, light cyclization and other reaction process routes are performed to produce oxadiazon. The oxadiazon synthesis method has the following advantages that the operation process is convenient and the total yield is up to 99%; the raw materials are domestic and are easy to obtain, such that the raw material cost is easily reduced and the market competitiveness can be improved; and the solid phosgene is used to replace the hypertoxic phosgene used in the existing process, such that the reaction is stable and safe, the pollutant discharging during the production process is reduced, and the process is the environmentally friendly chemical industry process.
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- Herbicidal 2-aryl-1,2,4-triazine-3,5(2H,4H)-diones and sulfur analogs thereof
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Herbicidal utility for 2-aryl-1,2,4-triazine-3,5(2H,4H)-diones and sulfur analogs is disclosed and exemplified. Many of the disclosed compounds are novel. Methods for preparing the herbicidal compounds and intermediates therefor are also disclosed.
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