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Synthesizing method for preparing high-purity 2,6-dichloro benzoxazole

A technology of dichlorobenzoxazole and chlorobenzoxazole, which is applied in the field of pesticide synthesis, can solve the problems of generating a large amount of phosgene, easily generating flushing materials, and dangerous operation, achieves mild reaction conditions and process, and simplifies the difficulty of operation. , the effect of high purity

Active Publication Date: 2012-07-11
JIANGSU TIANRONG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0015] In addition, this patent uses DMF as a catalyst. During the reaction process, the decomposition rate of trichloromethyl chloroformate is fast, and the speed of dripping trichloromethyl chloroformate is difficult to control, and it is easy to produce punching materials and a large amount of phosgene at the same time, which is dangerous to operate.

Method used

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  • Synthesizing method for preparing high-purity 2,6-dichloro benzoxazole
  • Synthesizing method for preparing high-purity 2,6-dichloro benzoxazole
  • Synthesizing method for preparing high-purity 2,6-dichloro benzoxazole

Examples

Experimental program
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Effect test

Embodiment 1

[0033] Drop into 50 grams (percent) 2-mercapto-6-chlorobenzoxazole and 250ml toluene and 30 grams (percentage) of bis(trichloromethyl) carbonate in 500ml four-necked reaction bottle, stir and heat up to 50 ℃, start to heat up at a rate of 0.5 ℃ / min, and keep warm for 10 minutes every time the temperature rises by 10 ℃. Hours, after the heat preservation is over, remove the solvent by distillation under reduced pressure, keep a vacuum of -0.07MPa during distillation, steam 200ml of toluene, cool to 0°C, stir for 0.5 hours, and centrifuge at a high speed to obtain 2,6-dichlorobenzoxazole, weight 43.5 grams, with a mass content of 99.2%, the recovery of the mother liquor is applied to the synthesis of the next batch of materials, and the molar yield is 98.1%. mp: 48~49℃.

[0034] Data:IR(KBr):v3271.4,3105.9,3036.1,1880.2,1781.5,1731.7,1613.8,1602.2,1528.8,1479.5,1455.8,1422.9,1392.4,1340.3,1322.4,1303.4,1259.7,1242.5,1218.3,1170.4,1143.7 , 1114.3, 1110.5, 1050.8, 1026.9, 941.2,...

Embodiment 2

[0036] In the 500ml four-necked reaction flask, drop into 50 grams (percentage) 2-mercapto-6-chlorobenzoxazole and 250ml xylene and 30 grams (percentage) of bis(trichloromethyl) carbonate, stir and heat up to 50°C, start to heat up at a rate of 0.5°C / min, and keep warm for 10 minutes every time the temperature rises by 10°C. When the temperature rises to 110°C, keep warm for 1 hour, then add 1.19 grams of trichloromethyl chloroformate dropwise, and keep warm for 0.5~ 1 hour, after the heat preservation is over, remove the solvent by distillation under reduced pressure, keep a vacuum of -0.07MPa during distillation, distill 200ml of xylene, cool to 0°C, stir for 0.5 hours, and centrifuge at high speed to obtain 2,6-dichlorobenzoxazole , a weight of 42.1 grams, a mass content of 99.0%, the recovery of the mother liquor is applied to the synthesis of the next batch of materials, and the molar yield is 98.1%.

Embodiment 3

[0038]Drop into 50 grams (percent) 2-mercapto-6-chlorobenzoxazole and 250ml toluene and 35 grams (percentage) of bis(trichloromethyl) carbonate in 500ml four-necked reaction flask, stir and heat up to 50 ℃, start to heat up at a rate of 0.5°C / min, and keep warm for 10 minutes every time the temperature rises by 10°C. Hours, after the heat preservation is over, remove the solvent by distillation under reduced pressure, keep a vacuum of -0.07MPa during distillation, steam 200ml of toluene, cool to 0°C, stir for 0.5 hours, and centrifuge at a high speed to obtain 2,6-dichlorobenzoxazole, weight 47.5 grams, with a mass content of 99.5%, the recovery of the mother liquor is applied to the synthesis of the next batch of materials, and the molar yield is 98.6%.

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Abstract

The invention discloses a synthesizing method for preparing high-purity 2,6-dichloro benzoxazole. The method comprises the following steps of: mixing 2-sulfydryl-6-dichloro benzoxazole and di(trichloromethyl) carbonic ester in a medium solvent; heating to 45-55 DEG C; slowly heating to 80-110 DEG C stage by stage; perserving heat for reacting at the temperature of 80-110 DEG C for 0.5-2 hours; slowly adding trichloromethyl chloroformate; then preserving heat for 0.5-1 hours; removing a part of the solvent after reacting; cooling and devitrifying; and separating a solid out. According to the synthesizing method, a catalyst is not used, only a stage heating method and light solidification are adopted, and a small amount of trichloromethyl chloroformate is added at a last stage, so that a reaction can be undergone completely approximately, and a high-purity finished product is directly obtained. The reaction condition and process of the synthesizing method are mild, over 99 percent by mass of 2,6-dichloro benzoxazole can be obtained directly under the condition that complicated treatment is not required, and the yield of the high-purity 2,6-dichloro benzoxazole reaches above 98 percent.

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: [0003] Route 1: [0004] [0005] 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%. [0006] Route 2: [0007] [0008] Route 2 uses chlorine gas as the chlorination agent, and chlorine gas will add to other positions of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D263/58
Inventor 许网保魏明阳臧伟新虞国新
Owner JIANGSU TIANRONG GROUP
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