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Method for preparing herbicide fenoxaprop-p-ethyl

A technology of fenoxaprop-p-ethyl and herbicides, which is applied in the field of chemical synthesis of fenoxaprop-p-ethyl, can solve problems affecting product quality, increasing raw material costs, and low reaction yield, and achieve high product quality and economical The effect of high raw material and yield

Inactive Publication Date: 2008-05-14
JIANGSU TIANRONG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] The shortcoming of method (1) (2) is that S (one) p-toluenesulfonyl ethyl propionate needs to be synthesized under the effect of triethylamine with L-ethyl lactate and p-toluenesulfonyl chloride, and Wherein p-toluenesulfonic acid is produced as a side reaction, which cannot be recovered, pollutes the environment, and increases the cost of raw materials
[0015] Method (3) The reaction yield of 2,6-dichlorobenzoxazole and hydroquinone is on the low side, and there are many secondary reactions with L (one) halopropionate ethyl ester, which affects product quality

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0025] (1), the preparation of (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionic acid (III)

[0026] Add 150 g of tap water into the reaction flask, cool to 5°C, add 63 g (1.5 mol) of solid sodium hydroxide, add 91 g (0.5 mol) of 2-(4-hydroxyphenoxy)propionic acid (II), stir to form a salt, Then add 1g of phase transfer catalyst, raise the temperature to 50°C, add 197g (0.525mol) of 50% 2,6-dichlorobenzoxazole (I) dropwise, then keep the temperature for 4 hours, then heat up to 80-90°C, keep the temperature After 1 hour, the toluene layer was separated and the pH of the aqueous layer was adjusted to 3-4 with hydrochloric acid. A gray powdery solid was precipitated and dried to obtain 172 g of crude product, with a yield of 95%.

[0027] (2), preparation of (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionate ethyl ester (IV)

[0028] Add (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionic acid (III) 172.5g (0.5mol) in the reaction flask, without 415...

Embodiment 2

[0030] (1), the preparation of (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionic acid (III)

[0031] Add 150 g of tap water in the reaction flask, cool to 5° C., add 84 g (2 mol) of solid sodium hydroxide, add 91 g (0.5 mol) of 2-(4-hydroxyphenoxy) propionic acid (II), stir to form a salt, and then Add 1 g of phase transfer catalyst, raise the temperature to 50° C., add 206 g (0.55 mol) of 50% 2,6-dichlorobenzoxazole (I) dropwise, then keep the temperature for 4 hours, then raise the temperature to 70-80° C., and keep the temperature for 1 After 1 hour, the toluene layer was separated, and the pH of the water layer was adjusted to 3-4 with hydrochloric acid. A gray powdery solid was precipitated, and the crude product was dried to obtain 173.4 g, with a yield of 96%.

[0032] (2), preparation of (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionate ethyl ester (IV)

[0033] Add (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionic acid (III) 172.5g (0.5...

Embodiment 3

[0035] Take by weighing 8.76 grams of fenoxaprop-methyl, 2.9 grams of oxapropen, and 12 grams of 20 grams of nonylphenol polyoxyethylene ether as a solvent, 4 grams of ethylene glycol, 0.2 grams of xanthan gum, and 0.15 grams of benzoic acid, and hydrolyze to 100 g to obtain the product. The obtained product is measured with a particle size distribution tester to have an average particle diameter of 1.05 microns.

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Abstract

The invention discloses a method for preparing fenoxaprop-p-ethyl of herbicide, which is characterized in that firstly, a compound (I) 2, 6-dichloro benzoxazoles and a compound (II) 2-(4-hydroxyphenoxy) propionic acid are reacted under alkaline condition, thereby getting (III) compound (R) -2-[4-(6-chlorine-1, 3-benzoxazoles-2-based oxygen) phenoxyl] propionic acid, and then reacted with ethanol to get a compound (IV)(R)-2-[4-(6-chlorine-1, 3-benzoxazoles-2-based oxygen) phenoxyl] ethyl propionate. The invention has the advantages of short reaction line, high yield, raw material saving, cost saving, less environmental pollution and high product quality.

Description

technical field [0001] The invention belongs to the field of organic chemistry, and in particular relates to a chemical synthesis method of fenoxaprop-p-ethyl. Background technique [0002] Fenoxaprop-p-ethyl (Fenoxaprop-p-ethyl) is a selective phenoxyacid herbicide of systemic conduction type. It is currently a herbicide with excellent performance in controlling gramineous weeds in wheat fields. It is mainly used for weeding in wheat fields, especially for wheat , durum wheat, rye, and triticale have special effects on vicious weeds that are difficult to control, and at the same time it is a post-emergent selective herbicide that can be directly used in soybeans, cotton, peanuts, sugar beets, flax, rapeseed, potatoes and vegetables, etc. The control of gramineous weeds in dicotyledonous crops is safe for dicotyledonous crops. The chemical name of oxaprop-ethyl-ethyl: ethyl (R)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy)phenoxy]propionate, the structural formula is: [0003] ...

Claims

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Application Information

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