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US 5,178,764 AGranted
Process for cleaning or purifying aqueous N-methylmorpholine-N-oxide solutions
AssigneeLenzing Aktiengesellschaft
InventorsStefan Astegger, Heinrich Firgo, Bernd Wolschner, Johann Manner, Karin Weinzierl, Stefan Zikeli, Dieter Eichinger
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Abstract
An aqueous N-methylmorpholine-N-oxide solution which was used as a spinning bath in the production of cellulosic products is regenerated by contacting it with active coal, silicon dioxide or alumina adsorbent and filtering, thereby reducing turbidity, eliminating nitrosoamine, decolorizing the solution and removing transition metals like iron therefrom.
Claims12
A process for cleaning an aqueous N-methylmorpholine-N-oxide solution containing transition metal impurities, comprising the steps of:
- (a) contacting the aqueous N-methylmorpholine-N-oxide solution containing transition metal impurities with a particulate adsorbent selected from the group consisting of aluminum oxide, silicon dioxide, and an adsorbing carbon, capable of adsorbing transition metals from said solution;
- and
- (b) thereafter filtering said solution to remove said adsorbent therefrom.
Dependencies are inferred from the claim text.