Selective recovery of a nitrophenolic by-product from nitration waste water by precipitation
US4986920A · kind A · utility
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6Claims
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Key dates
| Filing date | Jul 10, 1989 |
| Grant date | Jan 22, 1991 |
| Priority date | — |
| Expiry date | Jul 10, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S210/909
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process of selectively recovering a nitrophenolic by-product, namely 2,4-dinitrophenol and picric acid, from nitration waste water in substantially pure form through the control of the solution pH of the nitration waste water and subsequent precipitation is provided. By adjusting the solution pH of the nitration waste water with an acid to a pH in the range of from about 4.0 to 0.5, the solubility of the selected nitrophenolic by-products is affected and the crystal formation of the individual by-products controlled.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.