Continuous direct preparation of nitrophenols
US5030769A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1989 |
| Grant date | Jul 9, 1991 |
| Priority date | — |
| Expiry date | Nov 7, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C201/08
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Nitrophenols, in an isomer ratio para-nitrophenol/ortho-nitrophenol of at least 55/45, are continuously and directly prepared in steady state, by (a) establishing, in a confined reaction zone, an aqueous reaction solution including from 5% to 40% by weight of nitric acid, from 5% to 40% by weight of nitrous acid relative thereto, and an amount of nitrophenols within the limits of the solubility thereof in such reaction solution, (b) continuously introducing and reacting phenol and nitric acid into and with such reaction solution, at a rate of about 0.5 to 2.0 moles of nitric acid per mole of phenol, (c) maintaining the temperature in such confined reaction zone at a value ranging from about 10.degree. to about 40.degree. C. during such reaction, and (d) continuously withdrawing from such confined reaction zone admixture of para-nitrophenol and ortho-nitrophenol, in an isomer ratio para-nitrophenol/ortho-nitrophenol of at least 55/45.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.