Method for removing nitrotoluene in high-concentration waste acid

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...

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 enterprises.

Document 2 (Xie Hongyang, Zhou Chengfen. A treatment method for waste acid containing nitro compounds in TNT production [P]. CN: 101020586A, 2007-08-22) also uses toluene to extract trinitrotoluene (TNT) waste acid Nitro compounds, toluene also has a certain solubility in waste acid, which will cause secondary pollution

At present, there is no green, simple, recyclable, good extraction effect, and easy industrialization treatment method for high-concentration waste acid, and there is no report on the waste acid treatment in the production of dinitrotoluene (DNT).