Treatment/removal of byproduct aqueous effluents comprising hydroxynitro-aromatic compounds
US5820764A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1997 |
| Grant date | Oct 13, 1998 |
| Priority date | — |
| Expiry date | Oct 28, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/909
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
Objectionable byproduct aqueous effluents containing contaminating amounts of hydroxynitroaromatic compounds, in particular those aqueous effluents produced during the synthesis of nitroaromatic compounds, e.g., dinitrotoluenes, via reaction of an aromatic compound with nitric acid in the presence of sulfuric acid, are efficiently, facilely and economically treated/removed by (a) intimately contacting a mixture of at least one nitroaromatic compound and at least one hydroxynitroaromatic compound with an aqueous wash medium containing a neutralizing agent, (b) separating the resulting admixture into an organic phase and an aqueous phase, (c) recycling a fraction of the separated aqueous phase to the aqueous wash medium to thus constitute a portion thereof, and (d) periodically draining a fraction of the wash medium, whether to destruction thereof or to waste.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.