Process for making precipitated cellulose

In a process which comprises dissolving cellulose in a tertiary amine oxide solvent for the cellulose and thereafter shaping the solution and separating the cellulose from the tertiary amine oxide, the improvement wherein the solution is prepared with a solvent for the cellulose comprising a tertiary amine oxide selected from the group consisting of:

• (a) triethylamine oxide and
• (b) tertiary amine oxides having one or two of the valence bonds of the N substituted by a methyl residue and, where one methyl residue is present, the remaining valences are satisfied by a divalent radical forming a 5- to 7-membered ring structure having the N-atom in the ring;
• where two methyl residues are present, the remaining valence is satisfied by
• (1) a monovalent cyclic 5-, 6- or 7-membered residue which may be substituted only by methyl residues at the .beta.- or .epsilon.-positions, or
• (2) by a radical which can form a pseudo-cyclic structure through interaction with the N-oxide functionality, and
• from about 1.4% to about 29% by weight of water.

In a process which comprises dissolving cellulose in a tertiary amine oxide solvent for the cellulose and thereafter shaping the solution and separating the cellulose from the tertiary amine oxide, the improvement wherein the solution is prepared with a solvent for the cellulose comprising (1) a tertiary amine oxide having one of the following structures:

• ##STR8## where X is a radical chain completing a ring comprising 2 to 4 carbon atoms,
• R.sub.1 and R.sub.2 are H or methyl (Me);
• ##STR9## wherein Z is (i) a saturated or aromatic, unsaturated 5-, 6- or 7-membered ring which may be substituted only by methyl at the .beta.- or .epsilon.-positions or (ii) CH.sub.2 CH.sub.2 W where W can be OH, SH or NH.sub.2, or
• (2) triethylamine oxide
• and from about 1.4% to about 29% by weight of water.