Lenzing Aktiengesellschaft

Lenzinc Aktiengesellschaft

Johann Manner

Heinrich Firgo

Wolfram Kalt

Dieter Eichinger

Bruno Mangeng

Franz Schwenninger

Eduard Mulleder

Karin Weinzierl

Stefan Zikeli

Christoph Schrempf

Stephan Astegger

Bernd Wolschner

Arnold Nigsch

Peter Hinterholzer

Christian Hager

Werner Richardt

Dietmar Korger

Wolfgang Helmut Schkorwaga

Stefan Astegger

The invention is concerned with a process for the selective separation of morpholine from an aqueous solution containing morpholine, N-methylmorpholine and N-methylmorpholine-N-oxide, characterized by the following steps:

Process for selective separation of morpholine

The invention is concerned with a process for the production of an aqueous amine-oxide solution used in the amine-oxide process for the production of a mouldable cellulose solution, wherein aqueous, amine-oxide containing solutions produced in said amine-oxide process particularly as precipitation baths are purified and concentrated, characterized in that a microbiocide agent is added to said aqueous, amine-oxide containing solutions before, during or after purification.

Process for the production of an aqueous solution of a tertiary

The invention is concerned with a process for transporting a solution of cellulose in an aqueous tertiary amine-oxide through a component wherein said cellulose solution has different flow rates in said component, characterized in that an outlet wherethrough part of said cellulose solution is discharged from said component is provided at a point within said component whereat said flow rate is relatively low. (FIG. 2)

Process for transporting a solution of cellulose in an aqueous tertiary

Process for the purification of an aqueous solution of a tertiary

The invention is concerned with a process for the production of cellulose moulded bodies wherein a suspension of cellulose in an aqueous solution of a tertiary amine-oxide is transformed into a mouldable solution, said solution being extruded by means of a forming tool and conducted into a precipitation bath. The process is characterized in that at least part of the materials in devices and pipes for the transportation and processing of the solution, which material is in contact with the mouldable solution contains at a minimum of 90% up to a depth of at least 0,5 .mu.m, preferably more than 1 .mu.m, at least one element of the group consisting of titanium, zirconium, chromium and nickel in elementary form and/or in the form of compounds provided that the remaining of the material does not contain any of the elements of the group consisting of copper, molybdenum, tungsten or cobalt. By means of the use of certain elements and compounds according to the invention, it is possible to control the occurrence and the extent of exothermal degradation reactions in the cellulose solution.

Process for the production of cellulose moulded bodies

Moulding material and spinning material respectively containing cellulose, an aqueous tertiary amine-oxide, a non-solvent and a stabiliser, characterised in that, one or more stabilisers are provided which altogether have a basic and antioxidant action with the proviso that the basic stabiliser is not phosphate. The moulding material and spinning material respectively according to the invention are thermally stabilised against a runaway of the decomposition reaction. The degradation of the cellulose and of the amine-oxide is also largely prevented.

Moulding materials and spinning materials containing cellulose

Process for the purification of aqueous solutions of amine-oxides

Stable moulding material and spinning material containing cellulose

A solution of cellulose in water and N-methylmorpholine-N-oxide (NMMO) containing 2 to 44% by weight cellulose is stabilized at 0.01 to 1%, preferably 0.1% H.sub.2 O.sub.2 and 0.01 to 2%, preferably 0.1% of an H.sub.2 O.sub.2 stabilizer, preferably oxalic acid or a salt thereof during formation of the solution and during heating to prevent discoloration of the cellulose and reduce the composition of NMMO.

Cellulose solution in water and NMMO

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.

Process for cleaning or purifying aqueous N-methylmorpholine-N-oxide

There is disclosed a process for purifying aqueous solutions of N-methyl-morpholine N-oxide (NMMO), such as spinning bath solutions incurred in the production of cellulose products, in which process the solutions to be purified are contacted with an anion exchanger and the purified solutions are separated from the anion exchanger. The process is carried out in one step and the anion exchanger, as functional groups, exclusively contains quaternary tetraalkylammonium groups of the formulae

Process for purifying an aqueous solution of N-methyl-morpholine N-oxide

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Weyregg, Austria

Johann Manner