Process for separation of crude naphthalene dicarboxylic acid using reverse osmosis
US6562999B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 9, 2002 |
| Grant date | May 13, 2003 |
| Priority date | — |
| Expiry date | Jan 9, 2022 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01J23/83
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Disclosed is a process for purifying 2,6-naphthalene dicarboxylic acid produced by disproportionation and more efficiently recycling byproduct dipotassium salts which includes the steps of:a) Contacting an aqueous solution containing the disalt of 2,6-NDA(2,6-K2NDA) with carbon dioxide to form as a precipitate the monopotassium salt of 2,6-NDA (KHNDA) and an aqueous solution containing 2,3-KHNDA, K2NDA, and potassium bicarbonate;b) Disproportionating said monopotassium salt (KHNDA) to form 2,6-NDA and an aqueous solution containing K2NDA, and potassium bicarbonate;c) Separating said 2,6-NDA and concentrating said aqueous solution containing K2NDA and potassium bicarbonate by reverse osmosis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.