Purification process for aromatic dicarboxylic acids
US5481033A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1994 |
| Grant date | Jan 2, 1996 |
| Priority date | — |
| Expiry date | Dec 22, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/487
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Disclosed is a process for the purification of aromatic dicarboxylic acids in which the salt of an aliphatic diamine and an aromatic dicarboxylic acid is formed in an aqueous solvent, recrystallized, and contacted with an aliphatic dicarboxylic acid in an aqueous solvent such that the aromatic dicarboxylic acid is recoverable in the form of a purified precipitate. The remaining aqueous solute is a salt of the aliphatic diamine and aliphatic dicarboxylic acid and can be used as a starting material in the manufacture of certain polyamides (nylons). The invention is particularly applicable for purifying 2,6-naphthalene dicarboxylic acid, which is difficult otherwise to purify.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.