Method for preparing oxydiphthalic anhydrides using bicarbonate as catalyst
US6727370B1 · kind B1 · utility
9Cited by
6References
16Claims
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Key dates
| Filing date | Feb 24, 2003 |
| Grant date | Apr 27, 2004 |
| Priority date | — |
| Expiry date | Feb 24, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D307/89
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Oxydiphthalic anhydrides such as 4-oxydiphthalic anhydride are prepared by the reaction of a halophthalic anhydride with an alkali metal carbonate such as potassium carbonate in the presence of a catalyst system comprising an alkali metal bicarbonate such as potassium bicarbonate and a phase transfer catalyst, preferably a tetraarylphosphonium halide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.