Methods of extracting catalyst from a reaction mixture in the oxidation of cyclohexane to adipic acid
US6433220B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1999 |
| Grant date | Aug 13, 2002 |
| Priority date | — |
| Expiry date | Jun 30, 2019 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/584
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
This invention relates to methods of controlling the oxidation of cyclohexane to adipic acid in the presence of a monobasic acid solvent, by extracting the catalyst from the reaction mixture, outside the reaction zone. Substantially all the unreacted cyclohexane, the majority of adipic acid, and preferably substantially all the monobasic acid solvent are removed from the reaction product. In the case that substantially all the monobasic acid solvent is removed, protic solvent, is added intermittently or continuously in the reaction mixture during the removal of the monobasic acid solvent, preferably by distillation, thus preventing solids precipitation. Dipolar aprotic solvent is then added in the presence of an adequate amount of the protic solvent (the total of dipolar aprotic solvent and the protic solvent constituting a novel combination solvent) to maintain a single liquid phase, followed by a step of extracting substantially all the catalyst in protic solvent. The catalyst extract is preferably recycled to the reaction zone, where the cyclohexane is oxidized to adipic acid. Thus, the novel combination solvent, which is preferably a combination of cyclohexanone with water, all…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.