Dsm N.v.

Henricus F W Wolters

Wim Buijs

Nicolaas F Haasen

Rudolf P M Guit

Yvonne H Frentzen

Frank P W Agterberg

The invention relates to a process for the separation of a ketoxime or aldoxime from a ketoxime- or aldoxime-containing amide mixture in which the ketoxime or aldoxime is separated from the amide mixture by distillation. This has proved to be a very simple and direct method for separating the ketoxime and/or aldoxime from the desired amide.

Process for the separation of a ketoxime or aldoxime from an amide

Process to prepare &egr;-caprolactam by treating 6-aminocaproic acid, 6-aminocaproate ester or 6-aminocaproamide or mixtures comprising at least two of these compounds in the presence of superheated steam in which a gaseous mixture comprising &egr;-caprolactam and steam is obtained, wherein the process is carried out in the absence of a catalyst at a temperature between 250 and 400&deg; C. and at a pressure of between 0.5 and 2 MPa. The invention also encompasses a process to prepare &egr;-caprolactam starting from 6-aminocapronitrile by performing a hydrolysis and a subsequent step as described above.

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Echt, Netherlands

Henricus F W Wolters