Bayer Aktiengesellschaft

Harry Danziger

Bernd-Ulrich Kaiser

Otto Immel

Hans-Helmut Schwarz

Guido Rampart

Ludwig Deibele

Eberhard Bandtel

Klaus Starke

Jurgen Schroter

A process for the purification of acid-containing crude caprolactam obtained by the rearrangement of cyclohexanone oxime, wherein the crude caprolactam is mixed with from 0.8 to 2.0 equivalents of a base, from 3 to 6 parts by weight of toluene, based on caprolactam and from 2 to 10 parts by weight of water, based on inorganic constituents, separating the mixture into a toluene phase and two aqueous phases the upper of which containing all contaminants and discarding this phase.

Purification of caprolactam

A process for the purification of a solution of .epsilon.-caprolactam in benzene, toluene or xylene by washing with a liquid, wherein the washing liquid is a solution of .epsilon.-caprolactam in water in a weight ratio of from 15 : 1 to 1 : 3, which is used in a quantity of from 5 to 20% by weight, based on the solution of caprolactam in benzene, toluene or xylene, and wherein there are several washing stages so that the equilibrium between the two solutions can be readjusted.

Purification of .epsilon.-caprolactam

A process for the preparation of catalyst granulates from carbon black, boric acid, water and optionally nitrogenous additives, characterized in that from 3 to 50% by weight of a finely divided catalyst, which has already been used for the preparation of caprolactam and which has optionally been regenerated, are added.

Abrasion resistant catalyst

A process for the regeneration of a granular, supported catalyst of boric acid on carbon, wherein a part of the catalyst is removed from a fluidized bed reactor, in which cyclohexanone oxime is rearranged into caprolactam on this catalyst, when the 'differential content in the catalyst of organic nitrogen' is between 0.3 and 2.0% by weight and is replaced by an equal amount of regenerated catalyst so that the differential organic nitrogen content remains in the above-mentioned range, the quantity of catalyst removed is regenerated with air in a fluidized bed at a temperature of from 400.degree. to 700.degree. C. and is returned to the fluidized bed reactor used for rearrangement when a further part of the catalyst is removed therefrom for regeneration.

Catalyst regeneration of boric acid on carbon catalysts

Process for the removal of residues of solvent from crystallized .epsilon.-caprolactam, wherein the major quantity of solvent is removed in a first stage by distillation in the presence of water in an amount so that the water content of the residue of the first stage is from 0.5 to 6% by weight, and in a second stage by distilling water and any residues of solvent still present.

Process for the purification of epsilon-caprolactam

A process for the purification of .epsilon.-caprolactam, wherein .epsilon.-caprolactam is treated with potassium permanganate in the presence of from 0.01 to 5% by weight of water, based on caprolactam, and subsequently crystallized from toluene, benzene, ethylbenzene or xylene.

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Krefeld, Germany

Harry Danziger