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Method for removing nitrite ions

A technology of nitrite ion and nitric acid, applied in chemical instruments and methods, preparation of organic compounds, water/sludge/sewage treatment, etc., can solve the problem of high nitrite ion content, failure to meet product requirements, and waste water volume Large and other problems, to achieve the effect of less material dissolution loss, convenient operation, and less waste water

Inactive Publication Date: 2013-11-13
ZHEJIANG KANGFENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention is mainly aimed at the original neutralization-urea washing-water washing process. The content of nitrite ion in the existing nitrate is high, which cannot meet the product requirements. To solve technical problems such as pollution, a method for removing nitrite ions is provided, which is to use sulfonamide compounds to destroy nitrite ions produced by nitration neutralization and washing

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Use nitric acid and 2-chlorotrifluoromethylbenzene as raw materials to synthesize 2-chloro-5-nitrotrifluoromethylbenzene, add nitric acid to the nitration kettle, and add 2-chlorotrifluoromethylbenzene dropwise under stirring and cooling, After the reaction was completed, the layers were left to stand, and the lower layer obtained a crude product of 2-chloro-5-nitrotrifluoromethylbenzene (nitrated crude product) dissolved with a small amount of nitric acid.

[0017] Add 300g of the above-mentioned nitrated crude product into 300g of water, and after stirring completely, measure the total content of nitrous acid and nitric acid in the aqueous phase layer by neutralization titration method. It contains 4.54g (0.072moL) of nitric acid in terms of nitric acid, and add 30% amino acid prepared with water dropwise. 27g of sulfonic acid solution (0.083moL in sulfamic acid), control the washing temperature at 40-50°C, and stir for 45 minutes. The content of nitrite ions in the ni...

Embodiment 2

[0019] Use sulfuric acid, nitric acid and 4-chloro-3-nitrotrifluoromethylbenzene as raw materials to synthesize 4-chloro-3,5-dinitrotrifluoromethylbenzene, and add mixed acid prepared with sulfuric acid and nitric acid into the nitration kettle , add 4-chloro-3-nitrotrifluoromethylbenzene dropwise under stirring and cooling, after the reaction is over, let it stand for stratification, and the lower layer obtains 4-chloro-3,5-dinitro Crude trifluoromethylbenzene (crude nitration).

[0020] Add 200g of the above nitrated crude product into 100g of water, and after stirring completely, the sulfuric acid in the aqueous phase layer is measured by titration method to be 5.2g (0.053moL), and the total content of nitrous acid and nitric acid (calculated as nitric acid) is 1.4g (0.022moL). First add 56.3g of 10% sodium carbonate solution prepared with water (0.053moL of sodium carbonate) to neutralize equimolar sulfuric acid, then add dropwise 10.1g of 30% sulfamic acid solution prepar...

Embodiment 3

[0022] Synthesize 2,4-dichloro-5-nitrotrifluoromethylbenzene with sulfuric acid, nitric acid and 2,4-dichlorotrifluoromethylbenzene as raw materials, add mixed acid prepared with sulfuric acid and nitric acid into the nitration kettle, and 2,4-dichlorotrifluoromethylbenzene was added dropwise under stirring and cooling, and after the reaction was completed, the layers were left to stand, and the lower layer obtained 2,4-dichloro-5-nitrotrifluoromethyl dissolved with a small amount of sulfuric acid and nitric acid. Crude benzene (crude nitration).

[0023] Add 200g of the above nitrated crude product into 100g of water, and after stirring completely, the sulfuric acid in the aqueous phase layer is measured by titration method to be 3.6g (0.037moL), and the total content of nitrous acid and nitric acid (according to nitric acid) is 0.9g (0.014moL). First add 39.2g of 10% sodium carbonate solution prepared with water (0.037moL of sodium carbonate) to neutralize an equimolar amoun...

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Abstract

The invention belongs to the technical field of environment protection, particularly relating to a method for removing nitrite ions. The method comprises the following steps: adding nitrified crude containing the nitrite ions into water to be fully stirred, or adding waste water containing the nitrite ions into water to be fully stirred; measuring the content of nitrous acid and nitric acid in an aqueous phase layer or waste water; and adding sulfamic acid into the aqueous phase layer or the waste water to cause the molar ratio of total amount of nitrous acid and nitric acid to sulfamic acid to be 1:1-1.5, wherein stirring time is at least 0.5 hour. The method breaks the nitrite ions generated by nitrification, neutralization and washing with sulfonamides so as to solve the technical problems that the original neutralization-urea washing-rinsing technology has high nitrite ion content in nitrate and can not reach the requirements of products, and waste water amount generated by multiple washing is large, is easy to pollute environment and the like.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, and in particular relates to a method for removing nitrite ions. Background technique [0002] As we all know, the products after the nitration reaction need to be neutralized and washed, because nitric acid is dissolved in the nitrates, so that during neutralization and washing, the wastewater and nitrates contain nitrite ions, which can be combined with secondary amines in food or stomach role into nitrosamines. Nitrosamines have a strong carcinogenic effect, mainly causing esophageal cancer, gastric cancer, liver cancer and colorectal cancer. In addition, nitrosamines can also enter the fetus through the placenta, and pregnant women are particularly sensitive to it. Therefore, it is necessary to eliminate the nitrite ions in the waste water from nitrification and washing, and nitrates. There are many products synthesized from nitrates that require the content of nitrite ions...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C201/16C07C205/12C02F1/58
Inventor 张位德吴永良吴向峰吴康吴金桥
Owner ZHEJIANG KANGFENG CHEM
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