Process for the production and the recovery of terephthalic acid
US4357475A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 1980 |
| Grant date | Nov 2, 1982 |
| Priority date | — |
| Expiry date | Sep 11, 2000 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/47
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The reaction mixture obtained by oxidizing p-xylene in the presence of water as diluent, at a temperature comprised between 140.degree. and 220.degree. C., and consisting of terephthalic acid crystals in suspension in an aqueous solution comprising unreacted p-xylene, intermediate oxidation products thereof, the heavy-metal catalyst and water is introduced in the upper part of a sedimentation column wherein the acid is separated by gravity and is washed with a counter current of water introduced near the bottom of said column, the temperature of the washing zone being higher than the minimum value T.sub.w given by the equation T.sub.w =144+0.225 T.sub.R, wherein T.sub.R is the oxidation temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.