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Process for producing high-purity pentachloro nitrobenzene

A pentachloronitrobenzene, high-purity technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of good stability, high melting point and boiling point, difficult separation, etc., and achieve easy operation and control, The effect of simple preparation process and readily available raw materials

Inactive Publication Date: 2004-12-29
TAIYUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hexachlorobenzene is highly toxic and stable, causing serious pollution to the product, and it is extremely difficult to degrade in nature, causing great pollution to the natural environment
[0008] Pentachloronitrobenzene and hexachlorobenzene have similar structures, high melting points (146°C and 231°C, respectively) and high boiling points (323°C and 328°C), and it is difficult to separate them by conventional crystallization methods
However, in the vacuum distillation process, pentachloronitrobenzene will undergo complex thermal decomposition reactions, resulting in a serious decline in product quality
[0009] At present, the industrial product pentachloronitrobenzene contains 1-5% hexachlorobenzene and 0.5-6% trichloro and tetrachloro products, which seriously limit the application range of pentachloronitrobenzene

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0023] Add 1000ml of toluene to the three-necked flask, and then add 1300g of solid PCNB. Stir and heat, until there is no more solid, add 200ml of 10% NaOH solution that has been prepared. Stir and heat, boil and reflux for 20 minutes. Then carry out thermal liquid separation. Take the toluene solution of PCNB in ​​the lower layer, add 200ml of distilled water, stir and heat, and boil and reflux for 20 minutes. Separate the liquid again, take the lower layer solution, pH=7.3, cool and crystallize. Suction filtration obtained wet PCNB solid 1000g. After drying, 950 g of dry PCNB solids were obtained. Then dry PCNB is carried out underpressure distillation (2mmHg), the result makes high-purity pentachloronitrobenzene, adopts gas chromatograph to analyze content, see Table 1.

Embodiment approach 2

[0025] Add the used toluene of 1000ml example 1 in the there-necked flask, then add 1300g solid PCNB. Stir and heat, until there is no more solid, add 200ml of 10% NaOH solution that has been prepared. Stir and heat, boil and reflux for 20 minutes. Then carry out thermal liquid separation. Take the toluene solution of PCNB in ​​the lower layer, add 200ml of distilled water, stir and heat, and boil and reflux for 20 minutes. Separate the liquid again, take the lower layer solution, pH=7.0, cool and crystallize. Suction filtration obtained wet PCNB solid 1250g. Dry to obtain dry PCNB solid 1200g. Then dry PCNB is carried out underpressure distillation (10mmHg), the result makes high-purity pentachloronitrobenzene, adopts gas chromatography to analyze content, see Table 1.

Embodiment approach 3

[0027] Add the used toluene of 1000ml example 2 in the there-necked flask, then add 1300g solid PCNB. Stir and heat, until there is no more solid, add 300ml of 5% NaOH solution that has been prepared. Stir and heat, boil and reflux for 20 minutes. Then carry out thermal liquid separation. Take the toluene solution of PCNB in ​​the lower layer, add 200ml of distilled water, stir and heat, and boil and reflux for 20 minutes. Separate the liquid again, take the lower layer solution pH=7.1, cool and crystallize. Suction filtration obtained wet PCNB solid 1330g. Dry to obtain dry PCNB solid 1300g. Then dry PCNB is carried out underpressure distillation (8mmHg), the result makes high-purity pentachloronitrobenzene, adopts gas chromatograph to analyze content, see Table 1.

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Abstract

The high purity nitrobenzene pentachloride preparing process belongs to the field of organic chemical technology, and industrial nitrobenzene pentachloride product is purified through crystallization, alkaline cleaning and decompression distillation process, especially with its benzene hexachloride content reduced. The main process includes dissolving nitrobenzene pentachloride product in non-polar solvent or weak polar solvent to compound solution of concentration 10-80 wt%, preferably 40-65 wt%; adding alkali matter to neutralize, water washing to neutrality or slight alkali; crystallization to eliminate low chloride of nitrobenzene and acid matter; drying the crystal to eliminate organic solvent, decompression distillation to obtain high purity nitrobenzene pentachloride product. The high purity nitrobenzene pentachloride product has nitrobenzene pentachloride content up to 99.99 % and benzene hexachloride content lower than 0.1 %.

Description

Technical field: [0001] The method for preparing high-purity pentachloronitrobenzene belongs to the field of organic chemical industry, and specifically provides a method for preparing high-purity pentachloronitrobenzene by reducing the content of hexachlorobenzene. technical background: [0002] Pentachloronitrobenzene is an important broad-spectrum fungicide, which is widely used in the prevention and control of various plant diseases, especially for the prevention and treatment of wheat smut, cotton blight, fruit tree round spot root disease, forest, pasture, Blight, root rot, solanum solanum, damping-off, etc. of plants such as flowers, vegetables and medicinal materials. This product is stable in nature, low in toxicity, relatively safe to humans and animals, and widely used in agriculture in our country. [0003] There are many preparation methods of pentachloronitrobenzene, such as using chlorinated nitrobenzene or nitrochlorobenzene, and nitrated pentachlorobenzene....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C201/16C07C205/11
Inventor 李忠李安民阴丽华谢克昌
Owner TAIYUAN UNIV OF TECH
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