Preparation method of clomazone

A clomazone and solvent technology, applied in the direction of organic chemistry, etc., can solve the problems of not being able to obtain high-quality clomazone, increasing the processing difficulty and cost, and increasing the preparation cost.

Pending Publication Date: 2021-04-16
HUNAN HAILI CHEM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] 1. Adopt hydrogen chloride refining process: anhydrous HCl is passed into the crude clomazone, and while the yield is increased, the content is increased, but high-quality clomazone cannot be obtained;
[0007] 2. Distillation purification process: clomazone is easy to decompose under high temperature, and the yield is low, so high-quality clomazone cannot be obtained;
[0008] 3. Adopt continuous crystallization process: multiple crystallizers in series are required, relatively large equipment investment, long crystallization time, high energy consumption, and high cost; at the same time, clomazone products still contain more impurities
However, there are still following defects in this method: (1) the purification steps are complicated, and it is necessary to use hydrogen chloride gas, sodium hydroxide and sodium carbonate to process the crude product of clomazone before the recrystallization of isopropanol / petroleum ether can improve the clomazone (2) the use of hydrogen chloride gas, sodium hydroxide and sodium carbonate will increase the preparation cost, and waste water and waste gas will be easily produced in the preparation and use of hydrogen chloride gas, sodium hydroxide and sodium carbonate, while the new The waste water and waste gas produced will inevitably increase the difficulty and cost of treatment, making it difficult to achieve green purification; (3) clomiral products still contain more impurities

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A preparation method of clomazone, which uses the crude clomazone produced by the chlorpivaloyl chloride method as a raw material, dissolves it in a nitrile-containing solvent, cools down, crystallizes, and obtains high-quality clomazone, comprising the following steps:

[0027] In a 500mL three-necked flask equipped with a mechanical stirrer and a thermometer, 100g of clomazone crude product with a mass percentage of 88%, 5g of acetonitrile and 95g of n-hexane were successively added under stirring, and stirred at 30-40°C for 0.5h to make The crude clomazone was dissolved in a mixed solvent of acetonitrile and n-hexane, and the resulting solution was cooled and crystallized. When the temperature was above 0°C, the temperature was lowered at a rate of 20°C / h. When the temperature was below 0°C, Cool down at a rate of 5°C / h until the temperature is -10°C, keep it at -10°C for 1 hour, filter with a pre-cooled filter device, put the solid into a three-necked bottle, raise t...

Embodiment 2

[0029] A preparation method of clomazone, which uses the crude clomazone produced by the chlorpivaloyl chloride method as a raw material, dissolves it in a nitrile-containing solvent, cools down, crystallizes, and obtains high-quality clomazone, comprising the following steps:

[0030] In a 500mL three-necked flask equipped with a mechanical stirrer and a thermometer, add 100g of clomazone crude product with a mass percentage of 88%, 7.5g of acetonitrile and 142.5g of n-hexane successively under stirring, and stir at 30-40°C for 0.5h , dissolving the crude clomazone in a mixed solvent of acetonitrile and n-hexane, cooling and crystallizing the resulting solution, wherein when the temperature is above 0°C, the temperature is lowered at a rate of 20°C / h, and when the temperature is below 0°C Cool down at a rate of 5°C / h until the temperature is -10°C, keep warm at -10°C for 1 hour, filter with a pre-cooled filter device, put the solid into a three-necked bottle, and heat up to 35...

Embodiment 3

[0032] A preparation method of clomazone, which uses the crude clomazone produced by the chlorpivaloyl chloride method as a raw material, dissolves it in a nitrile-containing solvent, cools down, crystallizes, and obtains high-quality clomazone, comprising the following steps:

[0033] In a 500mL three-neck flask equipped with a mechanical stirrer and a thermometer, 100g of clomazone crude product with a mass percentage of 88%, 10g of propionitrile and 90g of cyclohexane were successively added under stirring, and stirred at 30-40°C for 0.5h to make The crude clomazone was dissolved in a mixed solvent of propionitrile and cyclohexane, and the resulting solution was cooled and crystallized. When the temperature was above 0°C, the temperature was lowered at a rate of 20°C / h, and when the temperature was below 0°C When the temperature is lowered at a rate of 5°C / h until the temperature is -10°C, and kept at -10°C for 1 hour, filtered with a pre-cooled filter device, the solid is t...

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PUM

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Abstract

The invention discloses a preparation method of clomazone, which comprises the following steps: dissolving a clomazone crude product used as a raw material in a nitrile-alkane mixed solvent, cooling the mixture, and crystallizing the mixture to obtain the clomazone. According to the preparation method, a mixed solvent of a nitrile solvent and alkanes is selected as a re-dissolving solvent of a crude clomazone product, wherein the crude clomazone product is directly dissolved in a nitrile-containing solvent, and the clomazone is separated from impurities by utilizing the characteristic that the clomazone and the impurities have different solubility in nitrile, so that the clomazone is separated from the impurities. The clomazone is separated out from the mixed solvent through cooling, and all or most of impurities are still left in the solution, so that the purification purpose is finally achieved. The purity of the prepared clomazone reaches 99% or above. The process omits the pretreatment step of hydrogen chloride gas and other substances on the clomazone crude product, and is lower in preparation cost, less in secondary pollution, and more environment-friendly. The method has the advantages of simple process, simple operation, low cost, good crystallization effect, environmental protection and the like, and is suitable for industrial popularization.

Description

technical field [0001] The invention relates to a preparation method of high-quality clomazone. Background technique [0002] Command is an organic heterocyclic selective pre-emergence herbicide developed and produced by FMC Corporation in 1984. The Chinese common name is clomazone and clomazone, and its chemical name is 2- (2-Chlorobenzyl)-4,4-dimethylisoxazolin-3-one. [0003] Clomazone is absorbed by the roots and young shoots of plants, transported upwards, diffuses to leaves through xylem, inhibits the synthesis of chlorophyll and carotene in sensitive plants, forms white seedlings, and dies in a short time. It is suitable for controlling annual grass weeds and broad-leaved weeds in crop fields such as soybeans and peanuts. It has the advantages of wide herbicidal spectrum, good weeding effect, long application period, and environmental safety. [0004] The existing methods for preparing clomazone mainly include the o-chlorobenzaldehyde method and the chloropivaloyl ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D261/04
Inventor 熊莉莉杜升华兰世林孔晓红程超刘源陈郭芹
Owner HUNAN HAILI CHEM IND
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