Process for the purification of para-nitrophenol
US3954892A · kind A · utility
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3References
8Claims
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Key dates
| Filing date | Mar 13, 1973 |
| Grant date | May 4, 1976 |
| Priority date | — |
| Expiry date | Mar 13, 1993 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C205/22
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
In the nitration of phenol with nitric acid, decantation of the residual acid, and steam distillation of ortho-nitrophenol to leave an aqueous distillation residue of para-nitrophenol, a cleaner purer crystalline para-nitrophenol product is obtained by cooling the hot distillation residue when it contains at least 0.5% of sodium bisulphite and is at pH 5.4 to 6.4.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.