Stamicarbon B.v.

Dsm N.v.

Rudolf L Zwart

Johan Thomas Tinge

Yvonne H Frentzen

Willem J Wassen

Reijer Goettsch

Marcellinus P Thijert

A process for depolymerizing nylon 6 and recovering caprolactam from the depolymerized products by extraction with alkyl phenolic compounds. Process steps include (a) treating a first mixture comprising nylon 6 with water at a temperature between about 200.degree. C. and about 400.degree. C. to yield a second mixture comprising depolymerized nylon 6 components, wherein the second mixture contains caprolactam at a concentration between about 5 wt. % and about 35 wt. %; (b) optionally, separating insoluble material from the second mixture; (c) extracting the second mixture with an extraction agent to yield an aqueous raffinate third mixture and an organic phase fourth mixture comprising caprolactam and the extraction agent, wherein the extraction agent is an alkyl phenol having a boiling point higher than that of the caprolactam; (d) recovering caprolactam from the organic phase fourth mixture by distillation; (e) recycling the aqueous raffinate third mixture to step (a).

Process for the recovery of caprolactam from waste containing nylon

A continuous process for separating hydrogen in high purity from a gaseous hydrogen-containing mixture by absorbing in an absorber unit the hydrogen by metal hydride forming particles suspended in an inert liqid and desorbing in a desorber unit the hydrogen from the hydrided particles includes the step of treating the suspension of the hydrided particles before entering the desorber unit to remove dissolved gaseous non-hydrogen components by stripping with hydrogen, preferably with a part of desorbed hydrogen. By this way it is possible to obtain hydrogen having a purity of more than 99.9%.

Continuous process for separating hydrogen in high purity from a gaseous

The process is directed to recovering .epsilon.-caprolactam from a reaction mixture containing .epsilon.-caprolactum and sulfuric acid by separating the caprolactam from the sulfuric acid by an extraction. Extraction includes the steps of neutralizing a part of said sulfuric acid with ammonia, ammonium sulfate, ammonium hydrogen sulfate or mixture thereof, to form an ammonium salt of at least part of said sulfuric acid as a neutralization product, thermally decomposing a part of the ammonium salt formed to produce a gaseous mixture of ammonia and sulfur dioxide and contacting another portion of the neutralization product with said gaseous mixture to produce ammonium hydrogen sulfate, ammonium sulfate or both, and neutralizing at least a part of the sulfuric acid in the reaction mixture with said ammonium hydrogen sulfate, ammonium sulfate or both.

Process for recovering .epsilon.-caprolactam from an

An improvement of processes for the recovery of .epsilon.-caprolactam wherein a neutralized sulfuric acid is subjected to thermal decomposition, forming a gaseous mixture of ammonia and sulfur dioxide which is thereafter converted to an aqueous solution of ammonium sulfite and/or ammonium hydrogen sulfite which is then used for neutralization of the reaction mixture of lactam and sulfuric acid.

Growing community of inventors

Sittard, Netherlands

Rudolf L Zwart