Method for purifying lactams
US6100396A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1999 |
| Grant date | Aug 8, 2000 |
| Priority date | — |
| Expiry date | Apr 23, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D201/08
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for purifying lactams by liquid-liquid extraction and/or processing with an ion exchange resin is disclosed. The method is useful for purifying lactams produced by the cyclising vapour-phase hydrolysis of an aliphatic aminonitrile, and comprises removing the major part of the ammonia before subjecting the lactam to liquid-liquid extraction by means of a solvent including an acidic solvent and/or contacting said lactam with a cation exchange resin. In most applications of the lactam, it is preferable to carry out a hydrogenation step on the compounds of the lactam solution comprising unsaturations, prior to or in addition to the liquid-liquid extraction step and/or the acidic resin contact step. The purification method may also include an oxidation step in addition to or instead of the hydrogenation step. Said method is preferably combined with a distillation step in the presence of a base.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.