Precipitative removal of nitrocresols from dinitrotoluene waste streams
US4597875A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 7, 1985 |
| Grant date | Jul 1, 1986 |
| Priority date | — |
| Expiry date | May 7, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/909
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
This invention relates to a process for removing nitrocresols and picric acid contaminants from a wastewater stream generated in the production of nitroaromatics, particularly dinitrotoluene, by the mixed acid technique. The process involves contacting the crude dinitrotoluene generated by the mixed acid technique with an alkaline medium to generate an alkaline wash water containing water soluble nitrocresols and picric acid therein. This wastewater is separated from the organic component and recycled for contact with further quantities of crude dinitrotoluene product from the reactor. When the concentration of the water soluble salts of nitrocresols and picric acid is of sufficient concentration the wash water is treated with aqueous acid in sufficient proportion to convert the water soluble salts to water insoluble organics. After treatment with acid, the organic material is separated from the wastewater and the organics incinerated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.