The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 05, 1996
Filed:
Jan. 18, 1995
Josef Ritz, Ludwigshafen, DE;
Rolf Fischer, Heidelberg, DE;
Werner Schnurr, Herxheim, DE;
Gu/ nther Achhammer, Mannheim, DE;
Hermann Luyken, Ludwigshafen, DE;
Eberhard Fuchs, Frankenthal, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
Crude capronitrile is purified by hydrogenation, subsequent treatment in an acidic medium and subsequent distillation in an alkaline medium, by a process in which (a) 6-aminocapronitrile is converted into crude caprolactam by reaction with water, (b) high boilers and low boilers are separated off from the crude caprolactam from step (a), (c) the crude caprolactam from step (b) is treated with hydrogen at from 50.degree. to 150.degree. C. and from 1.5 to 250 bar in the presence of a hydrogenation catalyst and, if desired, of a solvent to give a mixture A, (d1) mixture A in a solvent is passed, at from 30.degree. to 80.degree. C. and from 1 to 5 bar, over an ion exchanger containing terminal acid groups to give a mixture B1, or (d2) mixture A is distilled in the presence of sulfuric acid, any solvent present being removed before the addition of the sulfuric acid, to give a mixture B2, and (e) mixture B1 or mixture B2 is distilled in the presence of a base to give pure caprolactam.