Method for removing nitrotoluene in high-concentration waste acid

A nitrotoluene, high-concentration technology, applied in chemical instruments and methods, water/sludge/sewage treatment, extraction water/sewage treatment, etc., can solve the problem of restricting the comprehensive utilization of waste sulfuric acid, causing secondary pollution, difficult biological Degradation and other problems, to achieve significant treatment effect, less equipment, simple treatment steps

Inactive Publication Date: 2012-07-11
NANJING UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The production of dinitrotoluene is usually produced by nitrotoluene mixed acid as a nitrating agent, and toluene for nitration reaction. During this process, a large amount of waste acid containing nitrotoluene will be generated, and the content of sulfuric acid in the waste acid is about 70%. The appearance is reddish-brown viscous liquid. Since nitrotoluene is a kind of highly toxic organic pollution source and is difficult to biodegrade, thus limiting the comprehensive utilization of waste sulfuric acid, it is an old problem that plagues production enterprise

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Measure 10mL of waste acid and 20mL of perfluorodecalin (the ratio of waste acid to extractant is 1:2), stir in a single-necked flask at 80°C for 0.5 hours, pour it out and let it stand for 1 hour, and separate the lower layer of perfluoronaphthalene Alkanes were recovered after being washed with 40ml of chloroform (the ratio of stripping agent to extractant was 2:1) at room temperature. Separating the upper layer of acid liquid, it was detected by gas chromatography, the content of nitrotoluene compounds in the waste acid was 580ppm, and the removal rate reached 80.4%.

Embodiment 2

[0026] Measure 10mL of waste acid and 5mL of perfluorodecalin (the ratio of waste acid to extractant is 1:0.5), stir in a single-necked flask at 50°C for 1.5 hours, pour it out and let it stand for 1 hour, and separate the lower layer of perfluoronaphthalene Alkanes were recovered after washing with 2.5 mL of dichloromethane (0.5:1 ratio of stripping agent to extracting agent) at room temperature. Separating the upper layer of acid liquid, it was detected by gas chromatography, the content of nitrotoluene compounds in the waste acid was 709ppm, and the removal rate reached 76.0%.

Embodiment 3

[0028] Measure 10mL of waste acid and 10mL of perfluorodecalin (the ratio of waste acid to extractant is 1:1), stir in a single-necked flask at 60°C for 1 hour, pour it out and let it stand for 1 hour, and separate the lower layer of perfluoronaphthalene Alkanes were recovered after being washed with 50 mL of dichloromethane (the ratio of stripping agent to extractant was 5:1) at room temperature. Separating the upper layer of acid liquid, it was detected by gas chromatography, the content of nitrotoluene compound in the waste acid was 650ppm, and the removal rate reached 78.0%

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Abstract

The invention relates to a method for removing nitrotoluene in high-concentration waste acid. The method comprises adding an extractant into the high-concentration waste acid at a certain temperature, extracting, and separating the extractant from the waste acid; and recovering the extractant. Compared with the prior art, the invention has significant advantages that the invention has simple treatment steps, significant treatment effect and mononitrotoluene (MNT) and dinitrotoluene (DNT) removal rate up to above 99%, the treated high-concentration waste acid has high purity and can be directly used for other chemical processes, and the invention is suitable for industrialization; a perfluoro solvent serving as the extractant has good fluidity, chemical inertness and good phase separation performance, and has solubility for nitrotoluene compounds at a temperature higher than a critical temperature, thus it can be reutilized and maintains high removal rate; the invention directly treats the high-concentration waste acid without diluting with water, avoids subsequent wastewater treatment, and lowers the cost; and the inventive method has few apparatus, low manufacture cost, low investment and low running cost.

Description

technical field [0001] The invention relates to a treatment method for high-concentration waste acid, in particular to a method for removing nitrotoluene from high-concentration waste acid. Background technique [0002] Dinitrotoluene is an important chemical production raw material and intermediate in my country, and is often used in the manufacture of explosives, dyes, coatings, etc. The production of dinitrotoluene is usually produced by nitrating mixed acid with nitric acid and toluene. During this process, a large amount of waste acid containing nitrotoluene will be generated, and the content of sulfuric acid in the waste acid is about 70%. The appearance is a reddish-brown viscous liquid. Since nitrotoluene is a kind of highly toxic organic pollution source and is difficult to biodegrade, the comprehensive utilization of waste sulfuric acid is limited, which is an old problem that plagues production enterprises. [0003] Document 1 (Dong Yun, Yin Shiying. Discussion o...

Claims

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Application Information

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IPC IPC(8): C02F1/26C02F101/38
Inventor 赵禹光蔡春缪承蛟吕文方
Owner NANJING UNIV OF SCI & TECH
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