Method for isolation of a dianhydride and dianhydrides prepared by the method
US10407397B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 2017 |
| Grant date | Sep 10, 2019 |
| Priority date | — |
| Expiry date | Apr 19, 2037 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D307/89
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.