Process for the recovery of adipic acid
US5264624A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 1992 |
| Grant date | Nov 23, 1993 |
| Priority date | — |
| Expiry date | Feb 26, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/43
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
This invention relates to a process for the recovery of adipic acid from mother liquors collected during commercial production of adipic acid, wherein said mother liquors contain from 52 to 60% by weight of nitric acid calculated as HNO.sub.3, not taking into account the organic constituents, from 2 to 6% by weight of succinic acid, from 4 to 9% by weight of glutaric acid, and from 5 to 10% by weight of adipic acid, by selective crystallization of the adipic acid dissolved in said mother liquors by PA0 (a) adding an aqueous adipic acid solution having an adipic acid content of from 0.5 to 6% by weight to said mother liquor in the temperature range of from 30.degree. to 60.degree. C. in such a quantity that the concentration of nitric acid in the mixture is reduced to 35 to 50% by weight; PA0 (b) cooling the mixture by at least 5 degrees Celsius within a period of from 0.5 to 5 hours to induce crystallization of the adipic acid; PA0 (c) isolating the crystallized adipic acid by filtration; and PA0 (d) transferring the filtrate obtained in step (c) to a distillation apparatus for distillative workup of the glutaric acid contained therein.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.