Process for the purification of terephthalic acid
US4380662A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1981 |
| Grant date | Apr 19, 1983 |
| Priority date | — |
| Expiry date | Mar 16, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/48
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Disclosed is a process for the purification of a crude terephthalic acid product contaminated with up to 10% by weight of partially oxidized impurities including p-toluic acid and 4-carboxybenzaldehyde, comprising the steps of dissolving the crude product in water by heating up to a temperature at least about 5.degree. C. higher than necessary for having the resulting solution saturated with terephthalic acid; cooling the resulting solution down to a temperature not lower than about 185.degree. C. to precipitate purified crystals; recovering the purified crystals by solid-liquid separation at a temperature not lower than that used for the precipitation of the purified crystals; and washing the recovered crystals by contacting with water at a temperature which is at least as high as the temperature of the recovery step.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.