A kind of refining method of chlorothalonil raw material isophthalonitrile

A technology of isophthalonitrile and a purification method, which is applied in the field of purification of chlorothalonil raw material isophthalonitrile, can solve the problem that clean production and cost saving are not optimal, cannot be recycled, high temperature and vacuum degree, etc. problems, to achieve the effect of avoiding solid hazardous waste, less energy consumption, and mild process conditions

Active Publication Date: 2021-07-16
JIANGYIN SULI CHEM
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  • Abstract
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Problems solved by technology

But there are obvious disadvantages in this method: 1) Since the boiling point of isophthalonitrile is as high as 288°C, higher temperature and vacuum are required for distillation, and the highest distillation temperature is above 250°C. Since the melting point of isophthalonitrile is 163- 165°C, during the distillation process, it is very easy for the material to solidify and block the pipeline. The equipment needs to be dredged and cleaned frequently, resulting in low production efficiency
2) The solid residue produced after the distillation is a mixture of amide impurities, residual isophthalonitrile, and impurities generated by the decomposition of isophthalonitrile during high-temperature distillation, which cannot be recycled and can only be used as hazardous waste processing, which pollutes the environment and increases material consumption
[0005] In addition to distillation, isophthalonitrile can also be refined by recrystallization, but recrystallization is also a physical method like distillation, and the main impurities in isophthalonitrile, m-cyanobenzamide and m-cyanobenzamide, are not purified. Phthalamide is converted into isophthalonitrile by chemical reaction, and the solid residue produced after the solvent is recovered after refining is cyanobenzamide, isophthalamide, residual isophthalonitrile and other trace impurities as Hazardous waste treatment is not optimal in terms of clean production and cost savings

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  • A kind of refining method of chlorothalonil raw material isophthalonitrile

Examples

Experimental program
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Effect test

Embodiment 1

[0032] Put 2000g of crude isophthalonitrile and 4000g of toluene into a 20L glass reaction kettle equipped with a reflux condenser and a tail gas absorption tower, heat to 80°C, add 107g of thionyl chloride dropwise, react for 5 hours, and use water and liquid caustic soda for the tail gas Two-stage absorption tower absorbs, cools to 10°C, slowly adds 500g of water to quench the reaction, stirs for 0.5 hours, and separates the liquid. extinction reaction. 6000 g of water was added to the organic phase, and the temperature was azeotropically distilled to 100°C. The distillate is layered, the organic phase is dried with anhydrous sodium sulfate, and the water phase is used for azeotropic distillation. After distillation, it is cooled to room temperature, filtered, centrifuged, the filtrate is used for azeotropic distillation, and the filter cake is dried under vacuum and reduced pressure. Obtained 1955g refined product of isophthalonitrile. GC detection of isophthalonitrile: 9...

Embodiment 2

[0034] Put 2000g of crude isophthalonitrile and 4000g of toluene into a 20L glass reaction kettle equipped with a reflux condenser and a tail gas absorption tower, heat to 80°C, add 121g of sulfuryl chloride dropwise, and react for 5 hours. Absorb in the absorption tower, cool to 10°C, slowly add 500g of water to quench the reaction, stir for 0.5 hours, separate the liquid, remove the three wastes from the lower layer of water, add 500g of water to the upper organic phase to wash and separate the liquid, and use the water phase to quench the reaction . 6000 g of water was added to the organic phase, and the temperature was azeotropically distilled to 100°C. The distillate is layered, the organic phase is dried with anhydrous sodium sulfate and used mechanically, the aqueous phase is used for azeotropic distillation, cooled to room temperature after distillation, filtered, centrifuged, the filtrate is used for azeotropic distillation, and the filter cake is dried under vacuum a...

Embodiment 3

[0036] Put 2000g of crude isophthalonitrile and 4000g of chlorobenzene into a 20L glass reactor equipped with a reflux condenser and a tail gas absorption tower, heat to 80°C, add 114g of oxalyl chloride dropwise, and react for 5 hours. Absorb in the absorption tower, cool to 10°C, slowly add 500g of water to quench the reaction, stir for 0.5 hours, separate the liquid, remove the three wastes from the lower layer of water, add 500g of water to the upper organic phase to wash and separate the liquid, and use the water phase for quenching reaction. 6000 g of water was added to the organic phase, and the temperature was azeotropically distilled to 100°C. The distillate is layered, the organic phase is dried with anhydrous sodium sulfate and used mechanically, the aqueous phase is used for azeotropic distillation, cooled to room temperature after distillation, filtered, centrifuged, the filtrate is used for azeotropic distillation, and the filter cake is dried under vacuum and re...

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Abstract

The present invention relates to a kind of refining method of chlorothalonil raw material isophthalonitrile, described refining method is carried out according to the following steps: add isophthalonitrile and solvent in the refining kettle with reflux condenser and tail gas absorption tower; add Dehydration reaction of dehydrating agent; cool down, add water dropwise to quench the reaction, add washing water to the organic phase to stir and separate liquid, add water to the organic phase, heat up azeotropic distillation, separate the suspension of isophthalonitrile and water through solid-liquid separation, Phthalonitrile drying. The refining method proposed by the present invention has the following advantages: 1) Mild process conditions, no need for high temperature and high vacuum, no blockage of equipment, and less energy consumption 2) Directly transform impurities into products, which not only avoids solid hazardous waste after refining, but also The quantity of products is increased, and the economic benefit is high.

Description

technical field [0001] The invention relates to the field of pesticides, in particular to a method for refining chlorothalonil raw material isophthalonitrile. Background technique [0002] Chlorothalonil, i.e. tetrachloroisophthalonitrile, is a broad-spectrum, low-toxicity, low-residue, protective fungicide for agriculture and forestry. It has dual functions of prevention and treatment, long-lasting and stable, and can be used for wheat , rice, vegetables, fruit trees, peanuts, tea and other crops; in industry, it can be used as an antifungal agent for coatings, electrical appliances, leather, paper, cloth, etc. In industry, isophthalonitrile is used as raw material, chlorine gas is used as chlorinating agent, catalyzed by supported catalyst, high-temperature gas phase reaction is carried out in fixed-bed and fluid-bed reactors, and after the reaction is completed, it enters the trap for desublimation to obtain chlorothalonil product. [0003] Isophthalonitrile is industri...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C255/51C07C253/20C07C253/34
CPCC07C253/20C07C253/34C07C255/51
Inventor 缪金凤李新良黄岳兴汪静莉王成宇
Owner JIANGYIN SULI CHEM
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