Process for the production of terephthalic acid
USRE36008E · kind E · reissue
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1996 |
| Grant date | Dec 22, 1998 |
| Priority date | — |
| Expiry date | Apr 19, 2016 |
Classification
- Technology area (CPC —)General
Abstract
Terephthalic acid is produced by oxidation of para xylene, purified in an aqueous phase and recovered by precipitating a purified product from the aqueous phase, the aqueous phase mother liquor is then cooled or evaporated to produce a further less pure precipitate and a second mother liquor and the less pure precipitate is returned to the reaction medium and/or the water of the second mother liquor is used to dissolve the crude solid and/or the second mother liquor is treated to recover water which is used to wash the precipitate recovered from the aqueous solution. The process produces better yields of terephthalic acid, reduces the use of water and reduces problems in the disposal of polluted waste water.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.