Method for isolation of an aromatic dianhydride and aromatic dianhydrides prepared by the method
US11459314B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 6, 2019 |
| Grant date | Oct 4, 2022 |
| Priority date | — |
| Expiry date | Sep 27, 2039 |
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 using a sieve tray extraction column. 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.