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Clean halogenated aromatic nitroaniline diazotization technology

A technology for nitroaniline and halogenated aromatic hydrocarbons, which is applied in the field of cleaning halogenated aromatic hydrocarbon nitroaniline diazotization process and achieves the effect of convenient separation

Active Publication Date: 2015-04-01
JIANGSU LONGCHANG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Alkanols are reused after being dehydrated by molecular sieves

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] In a 250mL three-neck flask equipped with a thermometer and a reflux condenser, add 80mL of methanol containing 5.28g of HCl (0.15mol), 8.5g of p-chloro-o-nitroaniline and stir for 20min at room temperature; cool the reaction system to 0-5 ℃; slowly add 5g of sodium nitrite into the reaction solution, at this time control the reaction temperature not to exceed 5 ℃, and use starch potassium iodide test paper to test for 3 seconds and it will not turn blue, otherwise add urea until the sodium nitrite is not excessive. Filtered p-chloro-o-nitroaniline diazonium salt.

Embodiment 2

[0014] In a 250mL three-neck flask equipped with a thermometer and a reflux condenser, add 80mL of ethanol containing 5.28g of HCl (0.15mol), 8.5g of o-chloro-p-nitroaniline and stir at room temperature for 20min; cool the reaction system to 0-5 ℃; slowly add 5g of sodium nitrite into the reaction solution, at this time control the reaction temperature not to exceed 5 ℃, and use starch potassium iodide test paper to test for 3 seconds and it will not turn blue, otherwise add urea until the sodium nitrite is not excessive. Filter to obtain o-chloro-p-nitroaniline diazonium salt.

Embodiment 3

[0016] In a 250mL three-neck flask equipped with a thermometer and a reflux condenser, add 80mL of methanol containing 5.28g of HCl (0.15mol) and 8.5g of p-chloro-o-nitroaniline, which have been dried with molecular sieves, and stir for 20 minutes at room temperature; cool in an ice bath When the reaction system reaches 0-5°C; slowly add 5g of sodium nitrite into the reaction liquid, at this time control the reaction temperature not to exceed 5°C, and use starch potassium iodide test paper to test for 3 seconds and it will not turn blue, otherwise add urea until sub- Sodium nitrate is not in excess. Filtered p-chloro-o-nitroaniline diazonium salt.

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PUM

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Abstract

The invention relates to a clean halogenated aromatic nitroaniline diazotization technology. The clean halogenated aromatic nitroaniline diazotization technology is characterized in that in the whole acidification salt-forming process and the diazotization salt-forming process, alkyl alcohol replaces water so that waste water is not produced and separation is convenient and thus environmental protection and clean production are realized. Alkyl alcohol having the hydrogen chloride content of 5-35% replaces hydrochloric acid so that a halogenated aromatic nitroaniline hydrochloride alkyl alcohol suspension is obtained. While hydrogen chloride and sodium nitrite undergo a displacement reaction to produce nitrous acid, the reaction system undergoes a diazotization reaction to produce a diazo salt, and the diazo salt cannot be dissolved in an organic solvent and thus the diazo salt can be fast separated and then be used for the next reaction. The alkyl alcohol is dehydrated by a molecular sieve and then is recycled.

Description

technical field [0001] The invention relates to a clean diazotization process of halogenated aromatic hydrocarbon nitroaniline, which belongs to medicine and dye diazonium salt intermediates. Background technique [0002] Halogenated aromatic hydrocarbon nitroaniline diazonium salt is an important intermediate in the pharmaceutical and dye industries. There are many conventional synthesis methods for it. 1. Halogenated aromatic hydrocarbon nitroaniline, add hydrochloric acid, water, normal temperature or after cooling down after heating, add nitrous acid Sodium aqueous solution, heat preservation reaction at 0~5°C for 30 minutes to obtain diazonium salt solution. 2. Dissolve the halogenated aromatic hydrocarbon nitroaniline in lower alkanol and cool the reaction system to 0~5°C with an ice bath, add concentrated hydrochloric acid and stir well, then slowly add sodium nitrite to the reaction solution, and control the reaction temperature at this time Not exceeding 5°C, a dia...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C245/20
Inventor 赵雪松吴春江佘卫民王兆昌
Owner JIANGSU LONGCHANG CHEM