Method for producing purified phenylenedioxydiacetic acids
US6316666A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 2, 2000 |
| Grant date | Nov 13, 2001 |
| Priority date | — |
| Expiry date | Feb 2, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/43
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for producing phenylenedioxydiacetic acids of high purity at high yield from crude phenylenedioxydiacetic acids which mainly contains phenylenedioxydiacetic acids represented by the following general formula (I): ##STR1## PA1 wherein, R represents a hologen, carboxyl group or hydrocarbon group having 1-4 carbon atoms, and n represents an integer from 0 to 3, PA1 wherein an alkaline aqueous solution of the crude phenylenedioxydiacetic acids is mixed with a mineral acid to precipitate the phenylenedioxydiacetic acids, PA1 wherein at least 10% by weight of the alkaline aqueous solution is mixed with a mineral acid at 0 to 50.degree. C.; and, after completion of the mixing, the temperature of the mixture is kept at 80 to 110.degree. C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.