Direct continuous flow integration of production and purification of high purity iso- or terephthalic acid
US4675438A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1982 |
| Grant date | Jun 23, 1987 |
| Priority date | — |
| Expiry date | Apr 16, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/487
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
This invention pertains to the production of high purity iso- or terephthalic acid by the catalytic liquid phase oxidation of m- or p-xylene with molecular oxygen gas in the presence of a solvent system consisting essentially of 85 to 97 weight percent liquid benzoic acid and 15 to 3 weight percent water to provide a fluid feed for the purification of such phthalic acid by hydrogenation of the fluid effluent of such oxidation in the presence of a heterogeneous catalyst containing a Group VIII noble metal at an elevated temperature at which all the aromatic oxygen-containing products are in solution under the requisite elevated pressure to maintain a liquid phase of said solution followed by the precipitation of such phthalic acid from solution and the separation washing and drying of the precipitate. Such integration of process steps eliminates expensive and time consuming intermediate steps of precipitating impure iso- or terephthalic acid from oxidation effluent, separation, washing and drying said impure precipitate as well as purification of solvent for recycle to oxidation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.