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Method for synthesizing 2,6-dichlorobenzoxazole

A technology of dichlorobenzoxazole and chlorobenzoxazole, which is applied in the field of pesticide synthesis, can solve the problem that phosgene is not allowed to be stored, and achieve the effects of production cost advantage, good quality and high yield

Inactive Publication Date: 2009-02-25
JIANGSU TIANRONG GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, phosgene is a highly toxic chemical. The state strictly controls the production of production equipment, and expressly stipulates that phosgene is not allowed to be stored, packaged and transported. This is a judgment for manufacturers without phosgene resources to produce 2.6-dichlorobenzoxazole. death penalty

Method used

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  • Method for synthesizing 2,6-dichlorobenzoxazole
  • Method for synthesizing 2,6-dichlorobenzoxazole
  • Method for synthesizing 2,6-dichlorobenzoxazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Put 50 grams (100 percent) of 2-mercapto-6-chlorobenzoxazole, 250 ml toluene and 5 g DMF into a 500 ml four-necked reaction flask, stir and raise the temperature to 70-80 ° C, and start adding the weighed trichlorochloroformate dropwise. 30 grams of methyl ester (100 percent), the dropwise addition time is 7-8 hours, and the reflux reaction is 1.5 hours after the dropwise addition.

[0024] Carry out vacuum decompression precipitation, first remove toluene, then carry out high vacuum decompression distillation, and collect 85-95°C / -0.098~-0.095mpa distillate. The weight is 49 grams, the content is 98.5%, and the molar yield is 95.4%.

[0025] mp: 47~49℃.

[0026] Data:IR(KBr):v 3271.4,3105.9,3036.1,1880.2,1781.5,1731.7,1613.8,1602.2,1528.8,1479.5,1455.8,1422.9,1392.4,1340.3,1322.4,1303.4,1259.7,1242.5,1218.3,1170.4,1143.7, 1114.3, 1110.5, 1050.8, 1026.9, 941.2, 913.7, 867.1, 827.9, 815.0, 805.1, 756.3, 743.1, 730.8, 712.5, 701.8, 667.9, 626.5, 593.5, 554.0, 497.2, 47 ...

Embodiment 2

[0028] Put 50 grams (100 percent) of 2-mercapto-6-chlorobenzoxazole, 250 ml of toluene and 5 grams of DMF into a 500 ml four-necked reaction flask, stir and raise the temperature to 70-80 ° C, and start adding the weighed chloroformic acid dropwise Trichloromethyl ester 55 grams (100 percent), dropwise addition time 6-7h, add flow reaction 1.5 hours after the end of dropwise addition.

[0029] Carry out vacuum decompression precipitation, first remove toluene, then carry out high vacuum decompression distillation, and collect 85-95°C / -0.098~-0.095mpa distillate. The weight is 49.2 grams, the content is 98.49%, and the molar yield is 95.8%.

Embodiment 3

[0031] Put 50 grams (100 percent) of 2-mercapto-6-chlorobenzoxazole, 250 ml of toluene and 5 grams of DMF into a 500 ml four-necked reaction flask, stir and raise the temperature to 70-80 ° C, and start adding the weighed chloroformic acid dropwise Trichloromethyl ester 80 grams (100 percent), dropwise time 5-6h, reflux reaction for 2 hours after the dropwise addition.

[0032] Carry out vacuum decompression precipitation, first remove toluene, then carry out high vacuum decompression distillation, and collect 85-95°C / -0.095~-0.098mpa distillate. The weight is 49 grams, the content is 98.38%, and the molar yield is 95.32%.

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Abstract

The invention discloses a method for synthesizing 2, 6-dichlorobenzoxazole, which takes 2-hydrosulphonyl-6-dichlorobenzoxazole as raw material and trichloromethyl chloroformate or dicarbamate (trichloromethyl) as a chlorinating agent, and the raw material and the chlorinating agent react at the temperature of 65-120 DEG C to prepare the 2, 6-dichlorobenzoxazole; wherein, the mol ratio between the raw material and the chlorinating agent ranges from 1:0.2 to 2. The method has simple technique, safe use and high yield.

Description

technical field [0001] The invention belongs to the field of pesticide synthesis, in particular to a method for synthesizing a pesticide intermediate 2,6-dichlorobenzoxazole. Background technique [0002] 2,6-Dichlorobenzoxazole is a phenoxycarboxylic acid herbicide, fenoxaprop-methyl (chemical name: 2-[4-(6-chloro-2-benzoxazolyloxy)phenoxy Base] the important intermediate of ethyl propionate), its synthetic method has: route 1: [0003] [0004] Route 1 due to the use of PCl 5 It is a chlorinating agent, which seriously corrodes the equipment, especially the corrosion degree of the reactor is difficult to find. Once the reactor is broken and water enters the system, immediately contact with PCL 5 Violent reaction, causing an explosion accident. Bring serious hidden danger to safe production. The molar yield is 85-88%. [0005] Route 2: [0006] [0007] Route 2 uses chlorine gas as the chlorination agent, and chlorine gas will add to other positions of the benze...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D263/58
Inventor 许网保魏明阳金克明周国平虞国新唐良才徐卫清
Owner JIANGSU TIANRONG GROUP
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