Process for the preparation of &egr;-caprolactam
US6353100B1 · kind B1 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 1, 1999 |
| Grant date | Mar 5, 2002 |
| Priority date | — |
| Expiry date | Mar 1, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D201/08
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Process for the preparation of &egr;-caprolactam, in which in a step (a) a compound with the general formula:O=CH—(CH2)4—C(O)—R  (1) in which R is —OH, —NH2 or O—R′, in which R′ is an organic group with 1 to 10 carbon atoms, is contacted with ammonia and hydrogen in a suitable solvent at elevated pressure in the presence of a hydrogenation catalyst to a mixture of primary amino compounds and &egr;-caprolactam, followed by a separate second step (b) in which the primary amino compounds are reacted to &egr;-caprolactam, wherein the solvent in step (a) is an aqueous medium, including water, the yield to &egr;-caprolactam in step (a) is more than 10%, calculated on the initial molar amount of the compound according to formula (1), that &egr;-caprolactam is separated from the aqueous mixture obtained in step (a) by extraction and that the aqueous mixture resulting from the extraction, containing the primary amino compounds, is used in step (b).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.