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US 6,191,274 B1Granted
Recovery of ε-caprolactam
AssigneesDsm N.V., E.I. du Pont Nemous and Company
InventorsRudolf P. M. Guit, Yvonne H. Frentzen
Life of this patent
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Abstract
Process to separate ε-caprolactam from an aqueous mixture containing ε-caprolactam and at least 0.5 wt % oligomers, wherein the separation is performed by extraction using an organic extraction agent. The aqueous mixture may be obtained in a process to prepare ε-caprolactam starting from 6-aminocapronitrile or in a process to prepare ε-caprolactam starting from 6-aminocaproic acid.
Claims6
A process for separating ε-caprolactam from an aqueous mixture containing ε-caprolactam comprising:
- reacting at least one member selected from the group consisting of 6-aminocapronitrile, 6-aminocaproic acid and 6-aminocaproamide in water to obtain an aqueous mixture comprising ε-caprolactam and at least 0.5 wt % oligomers of amides;
- separating ε-caprolactam from the aqueous mixture by extraction using an organic compound with one or more hydroxy groups as an extraction agent.
Dependencies are inferred from the claim text.