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Bentazone decolouring and purifying method

A purification method, bentazon technology, applied in the field of fine chemical production technology, can solve problems such as the instability of water preparations, and achieve good effect, convenient operation, and good quality of the original medicine and water preparations

Active Publication Date: 2017-03-29
NANJING UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The product obtained by this method contains more impurities, the product is yellow or brown, and the content is less than 95%, and the prepared liquid is unstable

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Using isatoic anhydride as the raw material, first undergo reactions such as amide synthesis, sulfonation synthesis, and ring-closure synthesis in the dichloroethane solvent system, and then perform the following steps:

[0030] The first step is to finish the washing of the organic phase after the ring-closing synthesis, put the organic phase into the extraction kettle and slowly add alkali to adjust the pH=7~8, stop adding alkali, stir for half an hour and retest the pH=7~8, stop stirring and let stand ;

[0031] Second step, the solution of the first step is left to stand for stratification: the upper layer of alkali liquor is transferred to the decolorization kettle, and the bentazone content is measured in the alkali liquor by sampling, and activated carbon is added according to the bentazone weight wherein, and its amount is bentaxone. 15% of the loose weight, then heat up to 80-90°C and keep warm for 2 hours;

[0032] The third step, the material is transferred ...

Embodiment 2

[0036] Using isatoic anhydride as the raw material, first undergo reactions such as amide synthesis, sulfonation synthesis, and ring-closure synthesis in the dichloroethane solvent system, and then perform the following steps:

[0037] The first step is to finish washing the organic phase after the ring-closing synthesis, put the organic phase into the extraction kettle and slowly add alkali to adjust the pH=8~9, stop adding alkali, stir for half an hour and retest the pH=8~9, stop stirring and let stand ;

[0038] Second step, the solution of the first step is left to stand for stratification: the upper layer of alkali liquor is transferred to the decolorization kettle, and the bentazone content is measured in the alkali liquor by sampling, and activated carbon is added according to the bentazone weight wherein, and its amount is bentaxone. 10% of the loose weight, then heat up to 70-80°C and keep warm for 2 hours;

[0039] The third step is to transfer the material to the c...

Embodiment 3

[0043] Using isatoic anhydride as the raw material, first undergo reactions such as amide synthesis, sulfonation synthesis, and ring-closure synthesis in the dichloroethane solvent system, and then perform the following steps:

[0044] The first step is to finish washing the organic phase after the ring-closing synthesis, put the organic phase into the extraction kettle and slowly add alkali to adjust the pH=9~10, stop adding alkali, stir for half an hour and retest the pH=9~10, stop stirring and let stand ;

[0045] Second step, the solution of the first step is left to stand for stratification: the upper layer of alkali liquor is transferred to the decolorization kettle, and the bentazone content is measured in the alkali liquor by sampling, and activated carbon is added according to the bentazone weight wherein, and its amount is bentaxone. 15% of the loose weight, then heat up to 80-90°C and keep warm for 2 hours;

[0046] The third step, the material is transferred to th...

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PUM

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Abstract

The invention relates to a bentazone decolouring and purifying method. The method comprises the following steps: alkali extraction, including taking isatoic anhydride as a raw material, performing synthetic reactions, such as amidation, sulfonation and loop closure, in a dichloroethane solvent system, and carrying out washing and alkali addition for extraction to obtain an alkali-extracted liquid; decolouring, including, transferring the alkali-extracted liquid to a decolouring kettle, adding a certain amount of activated carbon according to the bentazone content, raising the temperature to 40-95 DEG C, and performing heat preservation for 1-5 h; filtration, including after the heat preservation is over, transferring the obtained material to a cooling kettle, performing fast stirring, leading brine in for cooling, performing plate filtration, allowing the obtained filtered liquid to pass an acidification kettle, and then blowing the plate to dry; acidification, including raising the temperature of the filtered liquid in the acidification kettle to 30-70 DEG C, slowly dropwise adding inorganic acid to the filtered liquid till the pH is less than 4, and allowing a great amount of bentazone to precipitate; and drying, including putting the precipitated material in a centrifugal machine for direct spin-drying, and then drying bentazone in a vacuum condition with the temperature in a range of 60-100 DEG C to obtain the final product. Through the method, a white bentazone primary drug is obtained.

Description

technical field [0001] The invention relates to the technical field of fine chemical production technology, in particular to a method for decolorizing and purifying bendazone. Background technique [0002] Bentazon is a widely used low-toxicity herbicide. Its mode of action and mechanism are mainly achieved by sodium salt of bentazone: contact-type selective post-emergence weeding, used for stem and leaf treatment at the seedling stage, and through leaf contact. kick in. When used in dry fields, it first penetrates into the chloroplast through the leaf surface to inhibit photosynthesis. When used in paddy fields, it can not only penetrate through the leaves but also absorb through the roots, and transmit to the stems and leaves, which strongly hinders the photosynthesis and water metabolism of weeds, causes nutrient starvation, and causes physiological dysfunction and death. The active ingredients are detoxified by metabolism to weakly active sugar conjugates in the tolera...

Claims

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Application Information

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IPC IPC(8): C07D285/16
CPCC07D285/16
Inventor 张海飞陆红健
Owner NANJING UNIV
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