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Method for synthesizing tebuthiuron technical material

A technology for the synthesis of terbuthiazide and its synthetic method, applied in the direction of organic chemistry, can solve the problems of low content, low yield, difficult separation and purification, etc., and achieve the effects of high product yield, excellent product quality, and reduced production cost

Active Publication Date: 2012-07-25
JIANGSU KUAIDA AGROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, the product yield is low, the content is low, and it is difficult to separate and purify

Method used

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  • Method for synthesizing tebuthiuron technical material

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Experimental program
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Embodiment 1

[0025] (1) Put 500 ml of toluene and 51.3 g (0.3 mol) of 5-tert-butyl-2-methylamino-1,3,4-thiadiazole (I) into a 1000 ml four-necked flask. While stirring, 46 g of 31% industrial hydrochloric acid was added dropwise. After the drop, the temperature was raised to reflux to azeotropically remove the water in the system to obtain 5-tert-butyl-2-methylamino-1,3,4-thiadiazole hydrochloride (II).

[0026] (2) Cool the toluene suspension of 5-tert-butyl-2-methylamino-1,3,4-thiadiazole hydrochloride (II) prepared above to 85° C. Pass through phosgene at a speed of min, and after passing light for 2 hours, the material becomes clear and transparent, and stop passing through phosgene. Introduce nitrogen to drive away residual phosgene and hydrogen chloride gas to obtain N-methyl-N-(5-tert-butyl-1,3,4-thiadiazole) carbamoyl chloride (III) toluene solution.

[0027] (3) Cool down the toluene solution of N-methyl-N-(5-tert-butyl-1,3,4-thiadiazole) carbamoyl chloride (III) prepared above ...

Embodiment 2

[0030] (1) drop into 1000L of toluene in the enamel kettle of 2000 liters, 5-tert-butyl-2-methylamino-1,3,150kg of 4-thiadiazole (I), under stirring state, drop 31% industrial Hydrochloric acid 124kg. After the drop, the temperature was raised to reflux, and the water in the system was azeotropically removed to obtain 5-tert-butyl-2-methylamino-1,3,4-thiadiazole hydrochloride (II).

[0031] (2) Cool the toluene suspension of 5-tert-butyl-2-methylamino-1,3,4-thiadiazole hydrochloride (II) prepared above to 85° C. 3 The flow rate of / h was passed through phosgene, and after 4 hours of light reaction, the material became clear and transparent, and the passage of phosgene was stopped. Introduce nitrogen to drive away residual phosgene and hydrogen chloride gas. N-methyl-N-(5-tert-butyl-1,3,4-thiadiazole) carbamoyl chloride (III) toluene solution was obtained.

[0032] (3) Cool the toluene solution of N-methyl-N-(5-tert-butyl-1,3,4-thiadiazole) carbamoyl chloride (III) prepared ...

Embodiment 3

[0035] (1) Put 500 ml of toluene and 51.3 g (0.3 mol) of 5-tert-butyl-2-methylamino-1,3,4-thiadiazole (I) into a 1000 ml four-necked flask. Under stirring, hydrogen chloride gas was introduced to saturation to obtain 5-tert-butyl-2-methylamino-1,3,4-thiadiazole hydrochloride (II).

[0036] Light transmission, amination, and water washing are the same as steps (2), (3) and (4) of Example 1. The obtained terbuthiauron technical product was 68.0 g, the content was 98.2%, and the yield was 97.6% (calculated as 5-tert-butyl-2-methylamino-1,3,4-thiadiazole).

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Abstract

The invention discloses a method for synthesizing a tebuthiuron technical material. The method comprises the following steps: taking 5-tert-butyl-2-methylamino-1,3,4-thiadiazole as a starting material; carrying out salt forming reaction and photochemical reaction in an organic solvent to prepare N-methyl-N-(5-tert-butyl-1,3,4-thiadiazole) carbamyl chloride; and introducing monomethylamine gas into the N-methyl-N-(5-tert-butyl-1,3,4-thiadiazole) carbamyl chloride to generate the tebuthiuron. The method has the advantages of simplicity in process, low production cost, high product purity, high yield, high production safety and the like.

Description

technical field [0001] The invention relates to a method for synthesizing the original drug of tebuthiauron. Background technique [0002] Tebuthiuron, common name tebuthiuron, chemical name is 1-(5-tert-butyl-1,3,4-thiadiazol-2-yl)-1,3-dimethylurea. It is a broad-spectrum herbicide for the control of herbs and grasses, mainly used to control weeds in non-arable land, shrubs in pasture areas, grasses and broad-leaved weeds in sugarcane fields. [0003] According to literature reports at home and abroad, there are three main methods for synthesizing terbuthiauron at present. (1) As disclosed in U.S. Patent us4283543, 5-tert-butyl-2-methylamino-1,3,4-thiadiazole is used as a starting material, and toluene is used as a solvent, and methyl isocyanate is added dropwise to react to obtain special Buthiuron original drug. The method uses methyl isocyanate, which is inflammable and explosive, has great toxicity, low boiling point, and extremely unsafe production. (2) As disclose...

Claims

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Application Information

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IPC IPC(8): C07D285/135
Inventor 施永平李梅芳李强韩邦友李云
Owner JIANGSU KUAIDA AGROCHEM
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