Process for the recovery of naphthalenedicarboxylic acid from poly (alkylene naphthalenedicarboxylate)
US6087531A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 19, 1998 |
| Grant date | Jul 11, 2000 |
| Priority date | — |
| Expiry date | Jun 19, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/09
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Disclosed is a process for the recovery of naphthalenedicarboxylic acid (NDA) from polyester materials prepared from and/or containing residues of NDA such as a poly(alkylene naphthalenedicarboxylate). In one embodiment, the process comprises contacting a polyester material prepared from and/or containing residues of NDA with water at a temperature of about 125 to 400.degree. C. in a pressured vessel to obtain an aqueous slurry of NDA and recovering the NDA. A second embodiment of the process comprises contacting such a polyester with an aqueous, alkali metal base solution to obtain an aqueous solution of a di-alkali metal naphthalenedicarboxylate salt, then neutralizing the aqueous solution with an acid to obtain an aqueous slurry or dispersion of NDA and recovering the NDA. The process is particularly useful for recovering 2,6-naphthalenedicarboxylic acid (2,6-NDA) from poly(ethylene naphthalenedicarboxylate) polyesters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.