Removal of bromine from phthalic anhydride
US4197247A · kind A · utility
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1References
5Claims
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Inventors
Key dates
| Filing date | Mar 19, 1979 |
| Grant date | Apr 8, 1980 |
| Priority date | — |
| Expiry date | Mar 19, 1999 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/487
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Bromine-substituted oxygen-containing impurities in phthalic anhydride which cannot be removed therefrom by distillation or a combination of heat treatment in the presence of a metal or a combination of catalytic hydrogenation and fractional distillation are removed by treating a mixture of vapors of such impure phthalic anhydride and water with a palladium catalyst prior to taking phthalic anhydride as a product fraction of fractional distillation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.