Recycling of acid-superbase conjugate ionic liquids by water removal in the lyocell spinning process

A process for the production of cellulose fibers, filaments, or a film, the process comprising:

• preparing an ionic liquid by combining acetic acid as a source of acetate anion and 7-methyl-1,5,7-triazabicyclo [4.4.0]dec-5-enium ([mTBDH]+) as a superbase cation in a 10 to 20 mole % stoichiometric excess of the acetic acid to the [mTBDH]+ in the ionic liquid, wherein the prepared ionic liquid consists of [mTBDH]+ and acetate;
• dissolving a cellulose substrate in the ionic liquid to produce a spinning dope;
• extruding the spinning dope through a spinneret in a coagulation bath containing water to form the cellulose fibers, filaments or a film from the spinning dope;
• withdrawing the ionic liquid in an aqueous mixture with water from the coagulation bath;
• recovering the ionic liquid from the aqueous mixture by removing the water;
• and
• optionally recycling the recovered ionic liquid to the dissolving step.