Method for preparing bentazone

A technology of bentazone and reaction, applied in the field of herbicide preparation, can solve the problems of difficult purification of isopropylaminosulfonyl chloride, unpleasant odor of 2-methylpyridine, increased production cost, etc., and achieves low production cost and high reaction efficiency. The effect of few steps and high recovery rate

Active Publication Date: 2010-09-15
江苏省农用激素工程技术研究中心有限公司
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Problems solved by technology

But above-mentioned two kinds of methods are difficult to realize industrialization, mainly because the isopropylaminosulfonyl chloride purification difficulty of one of raw material
[0004] German patent document DE2710382 and Chinese patent document CN1063688 disclose the method for preparing bentazone with isatoic anhydride as raw material, although the product quality obtained by this method is better than the previous two patents, but this method does not have intermediates in the production process N-isopropyl-2-aminobenzamide is further refined, so there are impurities such as anthranilic acid, and these impurities cannot be removed in the subsequent acid-base refining process, so that it is made into concentrated water After a long time of storage, it will precipitate and affect the use
The catalyst 2-picoline that adopts in this method smells bad in addition, and consumption is big, and recovery is difficult, has strengthened production cost

Method used

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  • Method for preparing bentazone

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Experimental program
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Effect test

Embodiment 1

[0019] The preparation method of the bentazone of present embodiment 1 has the following steps:

[0020] ①Add 40g of sulfonating agent sulfur trioxide and 250mL of organic solvent dichloroethane into the reaction flask, cool in an ice bath to -10°C ~ 0°C, slowly add 92.5g of organic base triethylamine dropwise under stirring and Start the reaction of generating sulfur trioxide / triethylamine double salt, stir and keep warm for 0.5h after dropping. Then the temperature was raised to 20°C, and 22.25 g of isopropylamine was added dropwise with stirring, and stirred for 0.3 h after the drop was completed. Then lower the temperature to 10°C, add 54.5g of methyl anthranilate under stirring to start the reaction to generate the corresponding sulfonate, continue to stir for 0.2h after the addition, then raise the temperature to 50°C to 55°C and then stir the reaction 0.3h.

[0021] ②Reduce the temperature of the system obtained in step ① to 15°C to 30°C, add 63g of phosphorus oxychlo...

Embodiment 2

[0025] The rest of this embodiment are basically the same as Example 1, except that the preparation of the intermediate N-methoxycarbonylphenyl-N'-isopropylaminobenzenesulfonamide.

[0026] ①Add 50mL of organic solvent dichloroethane and 18.5g of organic base triethylamine into the reaction bottle, cool in ice bath to -10℃~0℃, add 8g of sulfonating agent sulfur trioxide dropwise under stirring to start For the reaction of generating sulfur trioxide / triethylamine double salt, stir and keep warm for 0.5h after dripping. Then the temperature was raised to 20°C, and 4.43 g of isopropylamine was added dropwise with stirring, and stirred for 0.3 h after the drop was completed. Then lower the temperature to 10°C, add 10.9g of methyl anthranilate under stirring to start the reaction to generate the corresponding sulfonate, continue to stir for 0.2h after the addition, then raise the temperature to 80°C to 85°C and then stir the reaction 0.3h.

[0027] ②Reduce the temperature of the ...

Embodiment 3

[0030] The rest of this embodiment are basically the same as Example 1, except that the preparation of the intermediate N-methoxycarbonylphenyl-N'-isopropylaminobenzenesulfonamide.

[0031]①Add 220g of organic solvent chlorobenzene, 50.5g of organic base triethylamine and 19.3g of isopropylamine into the reaction bottle, then stir at 10℃~0℃ and slowly add 23.3g of sulfonating agent dropwise Chlorosulfonic acid to start the reaction of generating sulfur trioxide / triethylamine double salt, after the drop, the temperature was raised to 10°C, and then 15.1g of methyl anthranilate was added dropwise to start the reaction of generating the corresponding sulfonate , After dropping, stir and react at 50°C to 55°C for 0.5h.

[0032] ②Reduce the temperature of the system obtained in step ① to 15°C to 30°C, add 23.6g of phosphorus oxychloride dropwise, and after the dripping, raise the temperature to 60°C to 65°C and stir to generate N-methoxycarbonylphenyl-N' - Reaction of cumene sulfo...

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Abstract

The invention discloses a method for preparing bentazone, which comprises the following steps: 1), reacting a sulfonating agent, methyl anthranilate and isopropyl amine in an organic base and organic solution to generate a sulfonate; 2), adding phosphorus oxychloride into a system obtained by step 1) at the temperature of 15 to 30 DEG C, then raising the temperature to 50 to 85 DEG C, and stirring and reacting the reactants for 0.5 to 5 hours; 3), performing post treatment to obtain an intermediate, namely N-methoxycarbonylphenyl-N'-isopropylaminobenzsulfamide; and 4), adding an alcohol solvent and the N-methoxycarbonylphenyl-N'-isopropylaminobenzsulfamide into a reaction bottle, adding an alkali into the bottle to perform a reaction for 0.5 to 5 hours at the temperature of 30 to 65 DEG C, reclaiming the alcohol solvent, adding water and an acid into the solution until the pH value of the solution is less than or equal to 1 to crystallize and precipitate the bentazone, cooling the reaction solution, filtering the reaction solution, washing the filter cake, and drying the filter cake to obtain the finished product of the bentazone. The method of the invention is low in cost and pollution, high in yield and suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of a herbicide, in particular to a preparation method of bentazone. Background technique [0002] Benazone (also known as bentazone) has a scientific name of 3-isopropyl-1H-benzo-2,1,3-thiadiazin-4(3H)-one 2,2-dioxide, Grass pine is an important post-emergence herbicide, which was first developed by German BASF company and widely used in the world. [0003] German patent document DE2357063 discloses a kind of preparation method of bentazone, and it is to react with methyl anthranilate and isopropyl aminosulfonyl chloride, then use sodium methoxide ring closure to obtain bentazone. In addition, the German patent document DE2105687 also discloses a similar method, but finally obtains bentazone by closing the ring with phosgene. But above-mentioned two kinds of methods are difficult to realize industrialization, mainly because one of raw material isopropyl aminosulfonyl chloride purification difficulty. [...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D285/16
Inventor 孔繁蕾王广宇周月根
Owner 江苏省农用激素工程技术研究中心有限公司
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