Dsm N.v.

Other

Dsm IP Assets B.v.

Yvonne H Frentzen

Martin Booij

Jan Agnes Hendrix

Rudolf P M Guit

Nicolaas F Haasen

Stanislaus M P Mutsers

Rudolf L Zwart

Albert Arnold Van Geenen

Henricus F W Wolters

Jan Aj Hendrix

Marcellinus P Thijert

Cornelia E M Bronsaer

Eric Jozef Goethals

Bart Kurt Hommez

Antoon H Halderit

Nicolaas J M L Janssen

Nicolaas Mh Beckers

The invention relates to a process for preparing a melt-processable polylactam by contacting caprolactam monomer with an anionic polymerization catalyst, polymerizing said monomer and contacting the resulting polylactam with a protic compound. The anionic polymerization catalyst is chosen from the group consisting of alkali-earth-metal-lactamates and alkali-earth-metal-lactamate forming compounds and the protic compound has a pKa larger than 14. The resulting polylactam has a good melt-stability and very low cyclic dimer content.

Process for preparing a melt-processable polyamide composition

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 separate &egr;-caprolactam from an aqueous mixture containing &egr;-caprolactam and at least 0.5 wt % oligomers, wherein the separation is performed by extraction using an organic extraction agent. The aqueous mixture may be obtained in a process to prepare &egr;-caprolactam starting from 6-aminocapronitrile or in a process to prepare &egr;-caprolactam starting from 6-aminocaproic acid.

Recovery of &egr;-caprolactam

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

The invention relates to a process for depolymerising one or more polyamides in the presence of at least an aliphatic alcohol, the depolymerisation taking place with at most 40 mol. % catalyst. This process provides good selectivity towards the monomeric components of polyamides. This process moreover causes as few waste streams as possible.

Depolymerization of polyamides

The present invention relates to a process for treating polyamide-containing carpet waste by extracting the polyamide from the carpet waste with an extraction agent containing an aliphatic alcohol. The separated polyamide can then be recovered from the extract and recycled for further use. In addition, carpet waste containing two polyamides can be treated in accordance with the present invention so as to separately recover each polyamide. The process according to the present invention provides a high yield of the polyamide. The presence of other constituents normally present in carpets does not interfere with the separating and recycling of the polyamide.

Process for recovering and recycling polyamide from carpet waste

One or more polyamides can be depolymerized in the presence of at least one nitrogen-containing compound. The depolymerization takes place at a pressure between about 0.5 and about 5 atm. The polyamide may be in the form of carpet waste or other heterogeneous form. Advantages include better selectivity towards the polyamide monomeric components and use of low pressure equipment to effect depolymerization.

The present invention is for a method of preparing purified .epsilon.-caprolactam from carpet waste containing nylon-6. Contaminated .epsilon.-caprolactam is obtained by depolymerizing nylon-6 from carpet waste. A mixture of the contaminated .epsilon.-caprolactam and water is then hydrogenated in the presence of hydrogen and a hydrogenation catalyst in order to produce purified .epsilon.-caprolactam. The amount of contaminated .epsilon.-caprolactam in the mixture can be between 10 and 95% by weight.

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Venlo, Netherlands

Yvonne H Frentzen