Purification of terephthalic acid to relatively low levels of 4-carboxybenzaldehyde and catalyst therefor
US4629715A · kind A · utility
21Cited by
6References
17Claims
0Family size
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Key dates
| Filing date | Oct 7, 1985 |
| Grant date | Dec 16, 1986 |
| Priority date | — |
| Expiry date | Oct 7, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C67/60
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Aqueous solutions of crude terephthalic acid are purified to relatively low 4-carboxybenzaldehyde levels under hydrogenation conditions by using a layered catalyst bed. The aqueous terephthalic acid solution to be purified is first passed through a particulate primary catalyst layer constituted by palladium on active carbon and thereafter through a particulate secondary catalyst bed constituted by rhodium on active carbon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.