Method for preparing terbufos benzthiazuron

Abstract

The invention relates to a preparation method of tebuthiuron, which takes 2-methylamino-5-tert-butyl-1, 3, 4-thiadiazole (I), carbonyl dihalide or the derivatives (II) and methylamine as the raw materials, the tebuthiuron (IV) is prepared and obtained by the following reactions under the alkaline conditions, wherein, X in the carbonyl dihalide or in the derivatives (II) the carbonyl dihalide is a halogen element, and R is the halogen element or the alkoxy with 1 to 4 carbons. The method can effectively solve the potential risks and the serious pollution of the environment caused by using the acutely toxic substance methyl isocyanate in the traditional methods, allow the production of tebuthiuron with high yield, and can effectively make use of the by-products and reclaim the main solvents at the same time.

Description

technical field

[0001] The invention relates to a preparation method of the herbicide terbuthiauron. Background technique

[0002] Tebuthiuron (tebuthiuron), whose structure is shown in formula (IV), is a kind of destructive urea herbicide, which has a good control effect on annual and perennial grasses and broad-leaved weeds, and can be used to control / Except weeds in cultivated land, shrubs in pastures, grasses and broadleaf weeds in sugarcane fields.

[0003]

[0004] In documents such as DE 3113328A1, DE 3314190 and GB 1195672, it has been reported that the preparation method of terbuthiauron, all adopted is made of methyl isocyanate and 2-methylamino-5-tert-butyl-1,3 , 4-thiadiazole reaction mode. Because methyl isocyanate, which is a highly toxic substance, is used in these methods, there is a great potential danger, and the environment is seriously polluted, which is not conducive to large-scale industrial production. Contents of the invention

[0005] In vi...

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