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Method for preparing pendimethalin by aminating dimethyl dinitroanisole

A technology of dimethyl dinitroanisole and dinitroanisole, which is applied in the field of prepared pendimethalin, can solve problems such as a large amount of waste water, shorten operation time, increase reaction temperature, and reduce production The effect of wastewater

Inactive Publication Date: 2010-05-05
乐斯化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since 3-pentylamine is highly alkaline, calcium chloride is insoluble in alkaline water and appears turbid and paste-like. Therefore, neutralization and washing with water are required after the reaction is completed, resulting in a large amount of waste water.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] In a 250ml three-necked flask equipped with electric stirring, reflux condenser, and thermometer, put 23 grams of 98.1% 3,4-dimethyl-2,6-dinitroanisole, 0.3 grams of anhydrous chlorinated Calcium and 100ml of 98% 3-pentylamine. Heat to reflux (temperature 90-92° C.) with an electric heating mantle, and stir to react for 6 hours. The temperature was lowered to take samples, and thin-layer chromatography (TLC) was used to spot the plate. It was detected that there were no spots of 3,4-dimethyl-2,6-dinitroanisole, and the reaction was completed. Recover 3-pentylamine by distillation. When the distillate is very little and the temperature rises to 100°C, stop heating and slowly evacuate, and change to vacuum distillation. Control at a vacuum degree of 0.095-0.098MPa, a temperature of 98-100°C, and stop when there is no distillate. Then lower the temperature to about 50°C, add 80ml of absolute ethanol, stir for 10min, and then filter. . The content of pendimethalin detec...

Embodiment 2

[0014] In a 250ml three-necked flask, put 23.5 grams of 3,4-dimethyl-2,6-dinitroanisole with a content of 96.32%, 0.1 grams of cuprous chloride, 0.3 grams of anhydrous sodium sulfite, 3-pentylamine 50ml. Heat to reflux and stir the reaction for 5.5 hours. The temperature was lowered to take a sample, and there was no ether spot detected by TLC, so the reaction was stopped. Atmospheric distillation first recovers 3-pentylamine, and then vacuum distillation, controlled at a vacuum degree of 0.095-0.098MPa, at a temperature of 98-100°C, and stops when there is no distillate. Cool down to room temperature, add 80 ml of absolute ethanol, stir to dissolve and filter, and the filtrate is rotary evaporated under reduced pressure to 80°C without distillate, and cooled to obtain 27.2 g of solid. The content detected by HLPC was 98.58%, and the yield was 95.42%.

Embodiment 3

[0016] In a 10L stainless steel electric heating reactor, 2.3kg of 3,4-dimethyl-2,6-dinitroanisole, 7.5 grams of potassium chloride, 12 grams of anhydrous calcium chloride, 3.5 kg of 3-pentylamine; start stirring, heat and reflux for 6.5 hours, cool down to 80°C, take a sample and spot the plate, and detect that there is no ether spot. Atmospheric distillation to recover 3-pentylamine; stop heating when the material temperature reaches 100°C and there is no distillate. Cool down to 60°C with water flowing through the inner coil, add 5.5 kg of absolute ethanol, and stir for 10 minutes. Stop stirring, open the bottom valve of the kettle and let the material filter. Wash the reactor with a small amount of absolute ethanol, and filter the washing solution. Combine the filtrates and put them into the reaction kettle, remove absolute ethanol under normal pressure until there is no distillate at 100°C, and cool to obtain 2.8 kg of solid matter. Content 97.25%, yield 96.90%.

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Abstract

The invention relates to a method for preparing pendimethalin by aminating dimethyl-dinitro anisole. The method comprises the following concrete steps of: firstly, mixing, heating and refluxing 3,4-dimethyl-2,6-dinitroanisole, catalyst and excessive 3-pentyl amine for carrying out aminating reaction to generate N-(1-ethyl propyl)-3,4-dimethyl-2,6-dinitraniline; and secondly, distilling and reclaiming the unreacted 3-pentyl amine, cooling residues, and dissolving the cooled residuces with absolute ethanol, filtering to remove the catalyst and other insoluble substances, then removing ethanol to obtain 98 percent pendimethalin raw drug with the yield over 92 percent. Compared with the traditional synthetic production process of the pendimethalin raw drug, the preparation method not only has high yield, favorable quality and less wastewater, but also more importantly puts an end to the generation of N-nitrosamine substances in the pendimethalin raw drug.

Description

technical field [0001] The invention discloses a method for preparing pendimethalin, specifically a method for preparing pendimethalin by amination of dimethyl dinitroanisole. Background technique [0002] Pendimethalin (pendimethalin) chemical name N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitroaniline is a selective paddy field herbicide and Tobacco growth regulator, used for pre-emergence or post-emergence control of annual grass weeds and certain broad-leaved weeds, has the characteristics of good effect, low toxicity, less residue, and high environmental safety; Strong, not easy to be leached by rainwater, and environmentally friendly, it has been widely used and is one of the most widely used chemical pesticides in the world. Our country developed and produced around 2002, and the production capacity increased rapidly. Due to its low price, it has attracted many international merchants to purchase, and it has been exported in large quantities. [0003] At present, the pe...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/18
Inventor 张捷龙陈呈新雷进海
Owner 乐斯化学有限公司
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