Purification of acetic acid
US4061546A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 29, 1976 |
| Grant date | Dec 6, 1977 |
| Priority date | — |
| Expiry date | Mar 29, 1996 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/487
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Formic acid is removed from acetic acid substantially free of halide impurities but containing small amounts of formic acid by contacting the acid with a compound of hexavalent chromium and recovering the purified acid from the resulting mixture by distillation, ion-exchange, or the like. In a preferred embodiment, the acid to be purified is distilled in the presence of a solution of the hexavalent chromium compound, the purified acid being obtained as the overhead product while the bottoms stream contains the reduced chromium compound. With the preferred chromium trioxide as treating agent, this compound can be recovered for re-use by adding a strong mineral acid to the bottoms stream from the distillation, electrolytically oxidizing the chromium compound contained therein, and separating chromium trioxide from the strong mineral acid solution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.