Preparation method for 3,5,-dichloro-2,4,-difluoroaniline

A technology of difluoroaniline and trichloroaniline, which is applied in the field of preparation of 3,5-dichloro-2,4-difluoroaniline, can solve the problems of insufficient output and low quality, and achieve the goal of less side reactions and higher yield. Good efficiency and quality, energy-saving effect

Active Publication Date: 2016-07-27
安徽新北卡化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0015] To sum up the various reasons, there are currently only 1-2 domestic producers of

Method used

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  • Preparation method for 3,5,-dichloro-2,4,-difluoroaniline
  • Preparation method for 3,5,-dichloro-2,4,-difluoroaniline

Examples

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Embodiment 1

[0099] Preparation of intermediate 2,3,4-trichloronitrobenzene (II)

[0100] Preparation of mixed acid: Put 80g of nitric acid into a 500ml three-necked bottle, cool down to about 0°C, add 240g of concentrated sulfuric acid dropwise, and control the temperature not to exceed 10°C.

[0101]Add 200g of 1,2,3-trichlorobenzene (1.10mol) and 200g of dichloroethane into a 1000ml four-necked bottle, and add the mixed acid dropwise at a temperature of 50-60°C for 2 hours, and keep it warm for 30 minutes. Sampling GC analysis: 1,2,3-trichlorobenzene is less than 1%. Separate the layers: the organic layer was separated and the acid layer was extracted twice with dichloroethane. Combine the organic layers, wash with saturated sodium bicarbonate to pH = 7-8, dry over anhydrous sodium sulfate, filter, evaporate to dryness to recover dichloroethane, add 700g of n-hexane, heat up to dissolve, then cool down to about 15°C, pump After filtration and drying, 216g of finished product was obtai...

Embodiment 2

[0103] The preparation of intermediate 2,3,4-trichloroaniline (III):

[0104] Put 8g of iron powder (0.14mol), 80g of dichloroethane, 100g of water and 2g of ammonium chloride into a 500ml four-necked bottle. Under reflux, 11.5 g (0.051 mol) of 2,3,4-trichloronitrobenzene and 20 g of dichloroethane solution were added dropwise. After the dropwise addition, the solution was kept for 2 hours, and analyzed by GC, the reaction was basically completed. Filtrate, extract and wash the filtrate with water, separate the layers and combine the organic phases, and evaporate the solvent to obtain 8.2 g of the finished product, with a yield of 83%. 1H-NMR (400MHz, MeOD) δppm: 7.28 (d, 1H, J = 8Hz), 7.55 (d, 1H, J = 8Hz).

Embodiment 3

[0106] The preparation of intermediate 1,2,3,4-tetrachlorobenzene (IV):

[0107] Put 10 g (0.051 mol) of 2,3,4-trichloroaniline and 21 g of concentrated hydrochloric acid into a 500 ml four-necked bottle. Control the temperature in the range of -5-5°C and add dropwise an aqueous solution of 4g of sodium nitrite. After the addition is complete, keep the temperature for 1 hour for later use.

[0108] Put 50g of concentrated hydrochloric acid and 6g of cuprous chloride into another 1000ml four-neck bottle, add the previous nitrosation solution dropwise at about 50°C, raise the temperature to 80°C after adding, keep it warm for 1 hour, and then cool to 30 °C, extract the layers with dichloroethane, and evaporate to dryness to obtain 9 g of 1,2,3,4-tetrachlorobenzene. The GC analysis is over 98%, and the yield is 82%. 1H-NMR (400MHz, MeOD) δppm: 7.90 (s, 2H).

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Abstract

The invention relates to the field of organic synthesis, specifically to a preparation method for 3,5,-dichloro-2,4,-difluoroaniline and application thereof. The preparation method for 3,5,-dichloro-2,4,-difluoroaniline provided by the invention comprises the following steps: 1) nitration reaction; 2) reduction reaction; 3) diazotization reaction; 4) nitration reaction; 5) fluorination reaction; and 6) reduction reaction. The preparation method for 3,5,-dichloro-2,4,-difluoroaniline provided by the invention has the following beneficial effects: 1) the method has mild reaction conditions, is stable and controllable, has less active sites, is insusceptible to side reaction, and has good yield and quality in the whole line; and 2) raw materials are cheap and easily available, so cost can be effectively reduced, and energy is saved; meanwhile, the use of chlorine gas is avoided, so the method is environment-friendly.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method and application of 3,5-dichloro-2,4-difluoroaniline. Background technique [0002] Teflubenzuron was first developed and marketed by Celamerck GmbH & Co. in 1984. It is an important high-efficiency and low-toxicity insecticide among benzoylurea insecticides. It mainly kills pests by inhibiting the synthesis of chitin the goal of. Its mechanism of action is different from other insecticides, and it has the characteristics of high insecticidal activity, wide insecticidal spectrum, low residue, strong selectivity, and environmental friendliness. Because it is friendly to humans and animals and has extremely high biological activity, it is of positive significance to further develop the preparation method of furbron. The chemical structural formula of furbron is as follows: [0003] [0004] 3,5-dichloro-2,4-difluoroaniline is an important intermediate for ...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/36
Inventor 王永刘利刚张五军孙婧李倩黄俊杰谢剑飞康立涛
Owner 安徽新北卡化学有限公司
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