Basf Aktiengesellschaft

Basf Corporation

Josef Ritz

Hugo Fuchs

Franz-Josef Weiss

Gerald Neubauer

Erwin Thomas

Elmar Frommer

Otto-Alfred Grosskinsky

Rolf Hartmuth Fischer

Claus-Ulrich Priester

Wolfgang Hoelderich

Eberhard Fuchs

Michael Kopietz

Werner Steigleiter

Luc Guns

Hermann Luyken

Guido Voit

Werner Schnurr

Wolfgang Habermann

Juergen Hartig

Heinz Auer

Uwe Vagt

Peter Hammes

Rolf Schnabel

David Agar

Erwin Brunner

Peter Thoma

Gunther Achhammer

Ulrich Kalck

Hans J Wilfinger

Simon A Jones

Emile De Decker

Bernhard Holzknecht

Thomas P Losier

Paul Pijl

Alan Handerman

Gu/ Nther Achhammer

David Agab

Donald R Johnson

David Weatherford

Caprolactam is recovered from oligomers and/or polymers of caprolactam by cleavage of oligomers and/or polymers of caprolactam and subsequent working up by distillation of the caprolactam obtained in the cleavage, by a process including

Recovery of caprolactam from oligomers and/or polymers of caprolactam

A process for preparing caprolactam by cyclization of 6-aminocapronitrile in the presence of water at elevated temperature and in the presence or absence of a catalyst and a solvent, comprises

Preparation of caprolactam from 6-aminocapronitrile

Caprolactam is obtained from caprolactam-containing polymers in the presence of a base under reduced pressure by depolymerizing polymers which contain the repeating unit --[--N(H)--(CH.sub.2).sub.5 --C(O)--] or mixtures consisting essentially of

Obtaining caprolactam by cleavage of molten polycaprolactam

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.

Process for continuous purification of crude caprolactam prepared from

A process for the purification of caprolactam from crude caprolactam by distilling the crude caprolactam in the presence of an anorganic or organic acid.

Process for the purification of crude caprolactam

Recovery of caprolactam and of an alkali metal carbonate from distillation residues which are obtained in the purification of caprolactam and contain caprolactam and/or oligomers and/or polymers of caprolactam and also alkali metal hydroxides by

Recovery of caprolactam from distillation residues obtained in the

A process for recovering caprolactam from oligomers and/or polymers of caprolactam comprises the following steps:

Caprolactam is recovered from polycaprolactam by hydrolyric cleavage of polycaprolactam with from 5 to 50 parts by weight of water per part by weight of polycaprolactam at from 200.degree. to 350.degree. C. under superatmospheric pressure to give an aqueous solution or suspension which contains monomeric caprolactam and oligomers thereof and may contain polycaprolactam and subsequent isolation of monomeric caprolactam from the aqueous solution or suspension by distillation or extraction, by a process in which the hydrolyric cleavage is carried out in the presence of an alkali metal hydroxide at a pH of from 5 to 10.

Recovery of caprolactam from polycaprolactam

A process for preparing caprolactam by Beckmann rearrangement of cyclohexanone oxime with oleum at from 85.degree. to 125.degree. C. in a plurality of rearrangement stages arranged in series entails returning a portion of the reaction mixture leaving the last rearrangement stage to at least one of the preceding rearrangement stages.

Preparation of caprolactam by Beckmann rearrangement of cyclohexanone

A process for the preparation of hydroxylammonium salts by the reduction of nitrogen oxide (NO) with hydrogen in dilute aqueous mineral acid in the presence of a suspended platinum catalyst which is partially poisoned with arsenic, at elevated temperature, wherein the catalyst used is one which has been produced by precipitation of metallic platinum from an aqueous solution on to a suspended support in the presence of an oxidic arsenic compound, by means of a reducing agent.

Preparation of hydroxylammonium salts

A platinum-on-graphite catalyst having a platinum content of from 0.01 to 5% w/w, wherein the graphite support has an apparent density of from 1.7 to 2.2 g/ml and the use thereof as a hydrogenation catalyst.

Platinum-on-graphite catalysts

A process for working up aqueous mother liquors containing hydrochloric acid, sulfuric acid and their hydroxylammonium and ammonium salts, entails the mother liquors being intimately mixed with an excess of cyclohexanone based on the content of hydroxylammonium salts, while maintaining a pH of from 3 to 5.5 by adding alkali metal hydroxide solutions, and the cyclohexanone phase which contains cyclohexanone oxime being removed and washed with water until essentially free of chloride.

Work-up of aqueous mother liquors containing hydrochloric acid, sulfuric

A platinum-on-graphite catalyst having a platinum content of from 0.01 to 5% w/w, wherein the graphite support has a particle size of from 1 to 600 .mu.m and the following particle size distribution:

Platinum-on-graphite catalysts and the use thereof

Caprolactam is purified continuously by passing a 75-95% strength by weight aqueous caprolactam solution together with hydrogen at 50.degree.-95.degree. C. and 1.5-100 bar upward through a fixed-bed supported palladium or nickel catalyst in a tubular zone while maintaining a residence time of from 10 to 100 min.

Continuous purification of caprolactam

Crystalline hydroxylammonium sulfate is prepared by a process which comprises the following steps:

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Ludwigshafen, Germany

Josef Ritz